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Mitochondrial superoxide production contributes to vancomycin-induced renal tubular cell apoptosis
Abstract
Vancomycin chloride (VCM), a glycopeptide antibiotic, is widely used for the therapy of infections caused by methicillin-resistant Staphylococcus aureus. However, nephrotoxicity is a major adverse effect in VCM therapy. In this study, we investigated the cellular mechanisms underlying VCM-induced renal tubular cell injury in cultured LLC-PK1 cells. VCM induced a concentration- and time-dependent cell injury in LLC-PK1 cells. VCM caused increases in the numbers of annexin V-positive/PI-negative cells and TUNEL-positive cells, indicating the involvement of apoptotic cell death in VCM-induced renal cell injury. The VCM-induced apoptosis was accompanied by the activation of caspase-9 and caspase-3/7 and reversed by inhibitors of these caspases. Moreover, VCM caused an increase in intracellular reactive oxygen species production and mitochondrial membrane depolarization, which were reversed by vitamin E. In addition, mitochondrial complex I activity was inhibited by VCM as well as by the complex I inhibitor rotenone, and rotenone mimicked the VCM-induced LLC-PK1 cell injury. These findings suggest that VCM causes apoptotic cell death in LLC-PK1 cells by enhancing mitochondrial superoxide production leading to mitochondrial membrane depolarization followed by the caspase activities. Moreover, mitochondrial complex I may play an important role in superoxide production and renal tubular cell apoptosis induced by VCM.
... The few notable exceptions that did not appear to adequately fluoresce under DUV are calcein AM (live cell stain), certain Alexa Fluors, and certain fluorescent proteins. Among countless possibilities, we chose to demonstrate several applications of one of the most important assays used in biologythe investigation and quantification of cell and tissue viability [22,23]. As an alternative to the popular calcein AM and ethidium homodimer assay [24], we used SYTO 9 and propidium iodide for live and dead cell staining respectively. ...
... The use of vancomycin remains as a standard for treatment of methicillin-resistant Staphylococcus aureus (MRSA) [31] despite being linked to nephrotoxicity and acute kidney injury (AKI) for decades [32][33][34]. Previous studies had investigated the effects of vancomycin on kidney structure and function, invitro cell-level changes in viability, as well as mechanistic studies [22,[35][36][37][38], but there has yet to be a visual representation of kidney tissue viability, apart from area-specific images from Crawford et al. [35]. We demonstrate a simple method for large kidney tissue viability imaging, with exposure to vancomycin as an insult. ...
... ; were higher than that of the renal corpuscles. The increased vancomycin exposure decreased the viability of the tissue, displaying similar trends shown in [22,36,37,42]. An advantage of whole-tissue viability imaging is the ability to compare intra-tissue and inter-tissue variance in regions of interest. ...
Cellular imaging of thick samples requires physical sectioning or laser scanning microscopy, generally incompatible with high-throughput requirements. We developed fibre optic microscopy with ultraviolet (UV) surface excitation (FUSE), a portable, quantitative fluorescence imaging platform for thick tissue that substantially advances prior UV excitation approaches with illumination engineering and computational methods. Optic fibres delivered <300nm light with directional control, enabling unprecedented 50X widefield imaging on thick tissue with sub-nuclear clarity, and 3D topography of surface microstructure. Generative modelling of high-magnification images using our normalising flow architecture FUSE-Flow (open-source) enhanced low-magnification imaging by variational inference. Comprehensive validation comprised multi-scale fluorescence histology compared with standard H&E, and quantitative analyses of senescence, antibiotic toxicity, and nuclear DNA content in tissue models via efficient sampling of entire murine organs by thick slices up to 0.4×8×12mm and 1.3 million cells per surface. This technology addresses long-standing laboratory gaps for high-throughput studies for rapid cellular insights.
Teaser
Large-field functional cellular insights into thick tissue with generative AI enables accelerated decision-making
... VCM is a drug commonly used in severe infections, but the period and dose of its administration are restricted owing to VCM-induced notable nephrotoxic side effects ( € Oktem et al. 2005). VCM-induced nephrotoxicity happen in the range from 5% to 25% of patients (Nishino et al. 2003, Cetin et al. 2007) and the increase in this rate especially in patients who administer VCM at high dose or combination of VCM with other antibiotics (e.g., an increase 20-35% when administered concomitantly with aminoglycosides) (Arimura et al. 2012, Humanes et al. 2015. ...
... Caspase activities reflect caspase-dependent apoptosis. In cell culture models, Arimura et al. (2012) has reported that caspases-9 and -3/7 played a role in renal tubular cell injury caused by VCM in the porcine renal tubular epithelial cell lines (LLC-PK1 cells), and Im et al. (2017) has also revealed similar observations and showed that VCM increased caspase-3/7 activity in the immortalized proximal tubule epithelial cell line from a normal adult human kidney (HK-2 cells). However, activities of caspase induced by VCM has yet to be reported in experimental animal models. ...
... Initiator caspases in both pathways activate caspase-3 which is the major executioner caspase in renal apoptosis (Canacankatan et al. 2012). To date, there is no study showing the effects of VCM on extrinsic pathway of apoptosis; whereas, the effect of VCM on intrinsic pathway of apoptosis has already been investigated by Arimura et al. (2012). The study by Arimura et al. (2012) reported that ROS production was associated with VCMinduced renal cell injury and apoptosis in cultured renal tubular LLC-PK1 cells, and first-time, caspases-9 and -3/7 played a role in renal tubular cell injury induced by VCM. ...
Vancomycin (VCM), a glycopeptide antibiotic, is a drug widely used in severe infections. However, VCM induce notable nephrotoxic side effects. Naringenin (NAR) is a natural of flavonoid and are known as strongly antioxidant, nefroprotective, antiapoptotic, and anti-inflammatory. The purpose of this study was to determine the potential protective effects of NAR against VCM-induced nephrotoxicity by measuring apoptotic and oxidative stress markers and evaluating histopathological alterations in rats. For this purpose, we used male Wistar albino rats that divided into seven groups: (i) Control [saline, intraperitoneally (i.p.)], (ii) carboxymethyl cellulose (0.5% CMC, orally), (iii) VCM (400 mg/kg, i.p.), (iv) NAR100 (100 mg/kg, orally), (v) VCM + NAR25 (25 mg/kg, orally), (vi) VCM + NAR50 (50 mg/kg, orally), and (vii) VCM + NAR100 (100 mg/kg, orally) groups. VCM administration was started one day after the first treatment of NAR and continued across 7-day. Caspase-3, -8, and-9 activities and malondialdehyde (MDA) and nitric oxide (NO) levels were measured by colorimetric methods in the kidney tissues, creatinine, and blood urea nitrogen (BUN) levels were analyzed based on ELISA in serum. Caspase-3 and -8 activities, NO levels, serum creatinine and BUN levels were significantly higher in VCM group in comparison with VCM + NAR (25, 50, and 100) groups (p < 0.05). Caspase-9 activity and MDA were significantly higher in VCM group compared to VCM + NAR (25 and 50) groups (p < 0.05). Histopathological alterations in VCM group were significantly diminished by administration of NAR, especially NAR 25. In conclusion, NAR 25 and 50 mg have more potent protective effects on VCM-induced nephrotoxicity compared to NAR 100 mg.
... VCM accumulates in renal tissues via receptor-mediated endocytosis from urine and transporter-mediated uptake into tubular cells from blood, which elevates oxidative stress and apoptosis in tubular cells due to activation of their downstream caspases (Arimura et al., 2012;Qu et al., 2019). In addition, infiltration of immune cells such as dendritic cells, mast cells, neutrophils, eosinophils, and macrophages, which induce inflammation, has also been reported in VCM-induced renal injury (Perazella, 2019). ...
... VCM-induced renal injury increases tubular oxidative stress (Arimura et al., 2012;Qu et al., 2019), resulting in increased secretion of NGAL, a marker of tubular damage (Kim et al., 2016), in both mouse and human (Sampaio de Souza Garms et al., 2021;Kan et al., 2022). These suggested that the administration of 125 mg/kg VCM to uninephrectomized mice caused VCM-induced renal injury; therefore, the VCM dose for uninephrectomized mice was determined to be 125 mg/kg. ...
Although vancomycin (VCM)-frequently used to treat drug-resistant bacterial infections-often induces acute kidney injury (AKI), discontinuation of the drug is the only effective treatment; therefore, analysis of effective avoidance methods is urgently needed. Here, we report the differences in the induction of AKI by VCM in 1/2-nephrectomized mice depending on the time of administration. Despite the lack of difference in the accumulation of VCM in the kidney between the light (ZT2) and dark phases (ZT14), the expression of AKI markers due to VCM was observed only in the ZT2 treatment. Genomic analysis of the kidney suggested that the time of administration was involved in VCM-induced changes in monocyte and macrophage activity, and VCM had time-dependent effects on renal macrophage abundance, ATP activity, and IL-1β expression. Furthermore, the depletion of macrophages with clodronate abolished the induction of IL-1β and AKI marker expression by VCM administration at ZT2. This study provides evidence of the need for time-dependent pharmacodynamic considerations in the prevention of VCM-induced AKI as well as the potential for macrophage-targeted AKI therapy. Significance Statement There is a time of administration at which VCM-induced renal injury is more and less likely to occur and macrophages are involved in this difference. Therefore, there is a need for time-dependent pharmacodynamic considerations in the prevention of VCM-induced acute kidney injury as well as the potential for macrophage-targeted acute kidney injury therapy.
... In porcine proximal tubular epithelial cell lines, vancomycin (at 2 mM concentration) increased mitochondrial ROS production, reduced mitochondrial membrane potential, impaired activity of complex I of the electron transport chain, and increased apoptosis via activation of caspase-3, -7 and -9. [121][122][123] These effects may be mediated by peroxidation of the mitochondrial membrane protein cardiolipin 122 and could be partially or wholly mitigated by antioxidants such as vitamin E and MitoTEMPO. [121][122][123] Another in vitro study, however, found that vancomycin (at 1, 2.5 and 5 mM concentrations) increased oxygen consumption and ATP concentrations in proximal tubular epithelial cell lines. ...
... [121][122][123] These effects may be mediated by peroxidation of the mitochondrial membrane protein cardiolipin 122 and could be partially or wholly mitigated by antioxidants such as vitamin E and MitoTEMPO. [121][122][123] Another in vitro study, however, found that vancomycin (at 1, 2.5 and 5 mM concentrations) increased oxygen consumption and ATP concentrations in proximal tubular epithelial cell lines. 124 ...
While antibiotics are clearly important treatments for infection, antibiotic-induced modulation of the immune system can have detrimental effects on pathogen clearance and immune functionality, increasing the risk of secondary infection. These injurious consequences may be mediated, at least in part, through effects on the mitochondria, the functioning of which is already compromised by the underlying septic process. Here, we review the complex interactions between antibiotic administration, immune cell and mitochondrial dysfunction.
... Free radicals are induced by vancomycin through oxidative phosphorylation and activities of these radical are inhibited by defensive antioxidant system such as superoxide dismutase and catalase. These radicals produced by vancomycin cause mitochondrial depolarization of membrane potential with a release of cytochrome C and a subsequent activation of both caspases 9 and 3 (Arimura et al. 2012;Humanes et al. 2015). Cell death by apoptosis is involved in the process. ...
... Progressive and dose-dependent effects of this were tentatively recorded throughout the experiment as confirmed by the indices of kidney markers investigated. The superoxide (O − 2 ) radical produced by vancomycin causes depolarization of mitochondrial membrane potential with a release of cytochrome C and a subsequent activation of both caspases 9 and 3 (Arimura et al. 2012;Humanes et al. 2015). The latter is involved in apoptotic cell death. ...
The study targeted investigation of renoprotective ability of the Adansonia digitata on renal function and histopathological changes in vancomycin-induced nephrotoxicity in Wistar rats. Thirty (30) male Wistar rats (125 ± 0.3 g) were grouped into six of five each: (1) normal control, (2) received 200 mg/kg of VCM only, (3) 200 mg/kg VCM + 200 mg/kg of A. digitata extract, (4) 200 mg/kg VCM + 400 mg/kg of A. digitata extract, (5) 200 mg/kg VCM + vitamin E 1000 IU/kg, and (6) 200 mg/ kg + 25 mg/kg of hydrochlorothiazide (HCT). VCM was intraperitoneally administered twice a day for 14 days. Vitamin E was injected 5 min prior to every vancomycin injection. Blood and kidneys obtained were prepared for the determination of the parameters and histopathological studies, respectively. Creatinine and urea concentrations were significantly (p > 0.01) decreased across the test groups as against group 2 (VCM only). Variations of serum electrolytes were recorded against group 2 (VCM only). Total protein significantly (p < 0.05) reduced across the test groups against normal control. PCV, Hb, and WBC increased with little variation of RBC in group 5 (VCM + Vit. E) compared with group 6 (VCM + HTC). Similar observation was made in other groups fed with extract as against group 2 (VCM only). Results revealed severe necrosis of proximal tubule of VCM induced only while treated groups showed different degree of repair of the damage. A. digitata has demonstrated proactive inhibition against nephrotoxicity induced by extension of administration of vancomycin.
... Despite intense research in the past few decades, the exact mechanism of VAN-induced nephrotoxicity is unclear. Oxidative stress, inflammatory events, and apoptotic cell death are considered to be involved in the pathogenesis of nephrotoxicity (Arimura et al., 2012;Dieterich et al., 2009;Oktem et al., 2005;Sakamoto et al., 2017). Accordingly, the development of potential strategies to prevent VAN-induced toxicity without altering the efficacy of the antibiotic is of utmost importance in combating MRSA infections. ...
... Here it was shown that the treatment of cells with VAN consequences in the higher expression of Cas 4 and 5 indicating that the antibiotic caused the cellular damage. Similarly, the published reports have also indicated that the depolarization of the mitochondrial membranes and generation of reactive oxygen species followed by the activation of caspase 9 and 3/7 are involved in the VAN-induced nephrotoxicity (Arimura et al., 2012;Sakamoto et al., 2017). It has also been shown that VAN triggered cell apoptosis by releasing the cytochrome C from the mitochondria to the cytoplasm (Sakamoto et al., 2017). ...
Introduction
Vancomycin is used to treat bacterial infections but there is a risk of nephrotoxicity associated with it. Oxidative stress is the possible cause of this nephrotoxicity. Plant extracts have long been used in fighting oxidative stress and have proved quite useful. The present study investigated the treatment potential of Berberis aristata root extract against nephrotoxicity induced by vancomycin.
Methods
B. aristata was collected from Chikar Valley, Azad Kashmir, identified, and later analyzed by High-pressure liquid chromatography (HPLC). Vero cells were used to determine the effects of B. aristata extract. For the determination of apoptotic and anti-inflammatory effects cells were divided into three major groups; Control, Vancomycin, and Treated. The control groups were either left untreated or treated with 0.1% DMSO. Vancomycin group was treated with 0.6 mg/ml, 3 mg/ml, and 6 mg/ml of vancomycin, while treated groups were treated with (100 µg/ml, 200 µg/ml, 400 µg/ml) along with various vancomycin (0.6 mg/ml, 3 mg/ml, and 6 mg/ml) concentrations. The mRNA expression of antioxidant and proliferative markers (p53, p21, Cas 4, Cas 5, Cas 9, and Cyt-c) was assessed by qPCR.
Results
HPLC chromatogram indicated the presence of berberine component by comparing the peaks at retention time. The mRNA expression of all selected markers was found to be upregulated in the vancomycin group with a decrease of expression in treated groups, indicating the recovery from vancomycin-induced damage to kidney cells.
Conclusion
B. aristata extract can be used along with vancomycin treatment to minimize its toxicity.
... Caspase-3 is a key mediator of apoptosis in mammalian cells as it initiates the apoptotic process by activating other caspase enzymes [43,44]. Apoptotic cell death is involved in VCM-induced renal cell injury [45]. VCM directly triggers depolarization of mitochondrial membrane potential, releasing cytochrome c and activating caspase-9, which in turn activates caspase-3, a key component in the execution stage of apoptosis [15]. ...
... In the current study, VCM administration decreased the activities of the mitochondrial enzyme complexes and ATP levels in renal tissue. VCM was reported to inhibit the activity of mitochondrial complex I and this was postulated to play an important role in superoxide production and renal tubular cell apoptosis induced by VCM [45,51]. ...
Aim
Nephrotoxicity is the major limiting factor for the clinical use of vancomycin (VCM) for treatment against multi-resistant Gram-positive bacteria. The present research aimed to investigate the ability of selenium nanoparticles (SeNPs) to protect against VCM-induced nephrotoxicity in rats.
Main methods
Experimental rats were divided into five groups; the first was the normal control, the second was treated with VCM (200 mg/kg twice/day, i.p.) for 7 days. The third, fourth, and fifth groups were treated orally with SeNPs (0.5, 1, and 2 mg/kg/day); respectively. SeNPs were administered for 12 days before VCM, 1 week simultaneously with VCM, and for another 1 week after its administration.
Key findings
Levels of malondialdehyde (MDA), inducible nitric oxide synthase (iNOS), nitric oxide (NO), tumor necrosis factor-alpha (TNF-α), and kidney injury molecule-1 (KIM-1) were significantly increased in kidney tissue after VCM administration. Expression of adenosine 5′-monophosphate-activated protein kinase (AMPK), Bcl-2 associated X protein (Bax), caspase 3 and caspase 9 in kidney tissue was significantly increased, while the antioxidant enzymes, mitochondrial complexes, the ATP levels and B-cell lymphoma protein 2 (Bcl-2) were decreased in kidney in the VCM-treated rats compared to the normal control group. Treatment with SeNPs significantly decreased levels of MDA, iNOS, NO, TNF-α, and KIM-1 in the kidney tissue. Administration of SeNPs also downregulated the expression of the proapoptotic agents and enhanced the activities of the antioxidant enzymes and the mitochondrial enzyme complexes in the kidney.
Significance
SeNPs alleviated VCM-induced nephrotoxicity through their anti-oxidant, anti-inflammatory, anti-apoptotic and mitochondrial protective effects.
... Table 1. Nephrotoxicity of commonly used medications in critically ill patients [30][31][32][33][34][35][36]. ...
... Sakamoto et al. (2017) uncovered the possible nephrotoxic effect based on peroxidation of the mitochondrial membrane cardiolipin by vancomycin-induced production of intracellular ROS and activation of apoptosis in proximal tubular cells [42]. Apoptotic cell death induced by vancomycin may be associated with activation of specific caspases: caspase 9 and caspase 3/7 and extensive ROS production [34]. In the prospective multicenter Sapphire study (NCT01209169 ClinicalTrials.gov) ...
Acute kidney injury is a common complication in critically ill patients with sepsis and/or septic shock. Further, some essential antimicrobial treatment drugs are themselves nephrotoxic. For this reason, timely diagnosis and adequate therapeutic management are paramount. Of potential acute kidney injury (AKI) biomarkers, non-protein-coding RNAs are a subject of ongoing research. This review covers the pathophysiology of vancomycin and gentamicin nephrotoxicity in particular, septic AKI and the microRNAs involved in the pathophysiology of both syndromes. PubMED, UptoDate, MEDLINE and Cochrane databases were searched, using the terms: biomarkers, acute kidney injury, antibiotic nephrotoxicity, sepsis, miRNA and nephrotoxicity. A comprehensive review describing pathophysiology and potential biomarkers of septic and toxic acute kidney injury in septic patients was conducted. In addition, five miRNAs: miR-15a-5p, miR-192-5p, miR-155-5p, miR-486-5p and miR-423-5p specific to septic and toxic acute kidney injury in septic patients, treated by nephrotoxic antibiotic agents (vancomycin and gentamicin) were identified. However, while these are at the stage of clinical testing, preclinical and clinical trials are needed before they can be considered useful biomarkers or therapeutic targets of AKI in the context of antibiotic nephrotoxicity or septic injury.
... Mitochondrial DNA is double stranded like the nuclear DNA, but circular instead of linear. The mitochondrial genome encodes exclusively for two ribosomal RNAs (rRNAs), 22 transfer RNAs (tRNAs), and the messenger RNA (mRNA) of 13 protein subunits that are assembled with nuclear-encoded proteins to form the four enzymatic complexes constituting the mitochondrial (Teuber and Bader, 1976;Suzuki et al., 2013;Deris et al., 2014;Lu et al., 2016;Visentin et al., 2017) Doxycycline OATs Mitochondrial ribosome (Clark-Walker and Linnane, 1966;Babu et al., 2002;Houtkooper et al. 2013;Moullan et al., 2015) Gentamicin Megalin and OCT2 Mitochondrial ribosome Complex II (Prezant et al., 1993;Moestrup et al., 1995;Qian and Guan, 2009;Gai et al., 2016;O'reilly et al., 2019) Vancomycin OCTs Complex I (Sokol, 1991;Arimura et al., 2012;Fujiwara et al., 2012;Sakamoto et al., 2017) Anticancer Cisplatin OCTs Mitochondrial DNA VDAC (Yang et al., 2006;Garrido et al., 2008;Filipski et al., 2009;Ciarimboli et al., 2010) Gemcitabine CNTs and ENTs DNA polimerase γ (Mackey et al., 1998;Fowler et al., 2008) Ifosfamide OCT2 Complex I (Nissim et al., 2006;Knouzy et al., 2010;Ciarimboli et al., 2011) Methotrexate FRα, RFC, PCFT, OATs, and OATPs Mitochondrial TS (Hoar and Dimnik, 1985;Badagnani et al., 2006;Zhao et al., 2011;Visentin et al., 2012) Nitrosourea derivatives OCTs Mitochondrial DNA (Wunderlich et al., 1970;Pettepher et al., 1991;Chen et al., 2001 Frontiers in Physiology | www.frontiersin.org electron transport chain. ...
... Experiments with LLC-PK1 cells showed that vancomycin binds to and inhibit complex I activity, stimulating the production of superoxide, leading to peroxidation of the mitochondrial phospholipid cardiolipin and mitochondrial membrane depolarization followed by activation of the intrinsic apoptotic pathway. Carbonyl cyanide-4-(trifluoromethoxy) phenylhydrazone (FCCP), a protonophore that dissipates the proton gradient of the mitochondrial membrane, thereby inhibiting superoxide production and reducing cardiolipin peroxidation, and ameliorates vancomycin mitochondrial toxicity, suggesting that the ROS generated upon complex I inhibition promotes cardiolipin peroxidation followed by mitochondrial membrane depolarization and apoptosis (Orrenius, 2007;Arimura et al., 2012;Hanske et al., 2012;Sakamoto et al., 2017). ...
The kidneys utilize roughly 10% of the body’s oxygen supply to produce the energy required for accomplishing their primary function: the regulation of body fluid composition through secreting, filtering, and reabsorbing metabolites and nutrients. To ensure an adequate ATP supply, the kidneys are particularly enriched in mitochondria, having the second highest mitochondrial content and thus oxygen consumption of our body. The bulk of the ATP generated in the kidneys is consumed to move solutes toward (reabsorption) or from (secretion) the peritubular capillaries through the concerted action of an array of ATP-binding cassette (ABC) pumps and transporters. ABC pumps function upon direct ATP hydrolysis. Transporters are driven by the ion electrochemical gradients and the membrane potential generated by the asymmetric transport of ions across the plasma membrane mediated by the ATPase pumps. Some of these transporters, namely the polyspecific organic anion transporters (OATs), the organic anion transporting polypeptides (OATPs), and the organic cation transporters (OCTs) are highly expressed on the proximal tubular cell membranes and happen to also transport drugs whose levels in the proximal tubular cells can rapidly rise, thereby damaging the mitochondria and resulting in cell death and kidney injury. Drug-induced kidney injury (DIKI) is a growing public health concern and a major cause of drug attrition in drug development and post-marketing approval. As part of the article collection “Mitochondria in Renal Health and Disease,” here, we provide a critical overview of the main molecular mechanisms underlying the mitochondrial damage caused by drugs inducing nephrotoxicity.
... Although previous studies had revealed that proinflammatory oxidation, mitochondrial dysfunction and cellular apoptosis of renal tubular cells are involved in VAN-induced AKI, the real underlying mechanisms are still largely unknown (Arimura et al., 2012;Chen et al., 2016;Nishino et al., 2003;Oktem et al., 2005;Wang et al., 2017). In addition, there are few sensitive and reliable biomarkers for the nephrotoxicity of VAN during clinical practice. ...
... By comparing the outcomes of the two types of dose regimen, we can easily find that the concentration ranges of VAN in the plasma, kidney and renal tubule are narrower during treatment at 500 mg every 6 hours than in 1000 mg every 12 hours, but there was no clear difference in the plasma trough concentrations. VAN-associated nephrotoxicity has been investigated in cell lines including porcine renal proximal tubular epithelial cells, porcine kidney epithelial (LLC-PK1) and human proximal tubular (HK-2) cells, all of which demonstrated toxicity (Arimura et al., 2012;Chen et al., 2016;Humanes et al., 2015;Wang et al., 2017). In the present study, we were particularly interested in the effect of VAN on HKCs under the clinically relevant concentrations. ...
Vancomycin is a first-line treatment for invasive infections caused by multidrug-resistant gram-positive bacteria. However, vancomycin-induced nephrotoxicity is an increasing burden, particularly in patients with complex life-threatening conditions. Vancomycin-induced nephrotoxicity associated with clinically relevant exposure on the target site has not been well defined. This study aimed to acquire the concentration of vancomycin in the renal tubules and kidneys in humans using physiologically based pharmacokinetic (PBPK) modeling and simulation. Based upon the exposure of vancomycin in the renal tubule, the toxicity of vancomycin in human renal proximal tubular epithelial cells was examined with the XTT assay and in vitro metabolomics analysis. A rat PBPK model predicting plasma and kidney concentration-time profiles of vancomycin matched the observed behavior after a single administration of 10 mg/kg. The concentration of vancomycin in renal tubules was about 40-50 times higher than that in plasma. The human PBPK model transferred from the rat model predicted renal tubule concentrations of vancomycin as 316.1-2136.6 μg/mL at 500 mg every 6 hours, and 199.0-3932.5 μg/mL at 1000 mg every 12 hours. Vancomycin showed significant nephrotoxicity at 4 mg/mL in XTT assessment. In total, 11 lysophosphatidylcholines and one lysophosphatidylethanolamine were identified by metabolomics analysis. The concentration-dependent increase was evident in the release of lysophospholipids after vancomycin treatment (0.125-4 mg/mL) for 24 hours. Our study revealed the relationship between the exposure of vancomycin in the kidney and toxicity of vancomycin at clinically relevant concentrations achieved from a mechanical PBPK model. A series of lysophospholipids as potential metabolic markers of renal toxicity were identified.
... [41][42][43][44][45][46] AIN is mediated by an immunological reaction to vancomycin, 47 while two mechanisms have been suggested for ATN: vancomycin-induced direct oxidative stress and obstructive cast formation in proximal tubule cells. 48,49 Oxidative stress is an imbalance between free radicals and antioxidants within cells that leads to mitochondrial dysfunction and cellular apoptosis. Vancomycin has been shown to stimulate oxidative phosphorylation in cultured cells and produce oxygen free radicals. ...
... 50,51 The free radicals induce lipid peroxidation and the superoxides produced cause depolarization of mitochondrial membrane potential with the release of cytochrome c and activation of downstream caspases involved in apoptotic cell death. 49,52 Cast formation is another important mechanism for vancomycin-induced kidney injury. Uromodulin may interact with nanospheric vancomycin aggregates leading to tubular cast formation and subsequent ATN. ...
Drug-induced nephrotoxicity is responsible for 20% to 60% of cases of acute kidney injury in hospitalized patients and is associated with increased morbidity and mortality in both children and adults. Antimicrobials are one of the most common classes of medications prescribed globally and also among the most common causes of nephrotoxicity. A broad range of antimicrobial agents have been associated with nephrotoxicity, but the features of kidney injury vary based on the agent, its mechanism of injury and the site of toxicity within the kidney. Distinguishing nephrotoxicity caused by an antimicrobial agent from other potential inciting factors is important to facilitate both early recognition of drug toxicity and prompt cessation of an offending drug, as well as to avoid unnecessary discontinuation of an innocuous therapy. This review will detail the different types of antimicrobial-induced nephrotoxicity: acute tubular necrosis, acute interstitial nephritis and obstructive nephropathy. It will also describe the mechanism of injury caused by specific antimicrobial agents and classes (vancomycin, aminoglycosides, polymyxins, antivirals, amphotericin B), highlight the toxicodynamics of these drugs and provide guidance on administration or monitoring practices that can mitigate toxicity, when known. Particular attention will be paid to paediatric patients, when applicable, in whom nephrotoxin exposure is an often-underappreciated cause of kidney injury.
... No study investigated the extrinsic pathway of apoptosis. However, the effect of VA on the intrinsic pathway was studied and the results indicated that the production of ROS was related to VA-induced renal cell damage (Arimura et al. 2012, Kandemir et al. 2018). VA has a stimulating role in free radical production and oxidative phosphorylation by elevating oxygen consumption and cellular adenosine triphosphate concentrations. ...
... Reactive oxygen species generation stimulated by VA causes apoptosis in renal tubular cells via the depolarization of mitochondrial membrane potential. This activates caspase-9, which in turn, induces caspase-3 activation (Arimura et al. 2012). Previous studies demonstrated the antioxidant, anti-inflammatory, anti-apoptotic, and immunomodulatory effects of SLY. ...
Silymarin (SLY), a flavonoid complex isolated from the seeds of Silybum marianum (Asteraceae), has antioxidant, anti-apoptotic, anti-inflammatory, and anti-lipid peroxidative effects. Vancomycin (VA), used for treating serious infections, has been associated with nephrotoxicity, which limits its use. Therefore, this study aimed to investigate the potential renoprotective effects of SLY on VA-induced nephrotoxicity using renal, apoptotic (caspase-3, caspase-8, and caspase-9 enzyme activities), and oxidative stress [nitric oxide (NO) and malondialdehyde (MDA)] markers; serum blood urea nitrogen (BUN) and creatinine levels; and histopathological examination. A total of 49 male Wistar albino rats were used (n = 7): control [saline, intraperitoneally (i.p.)], dimethyl sulfoxide (i.p.), VA [400 mg/(kg-day), i.p.], SLY100 [100 mg/(kg-day), i.p.], VA + SLY50 [50 mg/(kg-day), i.p.], VA + SLY100 [100 mg/(kg-day), i.p.], and VA + SLY200 [200 mg/(kg-day), i.p.]. SLY was administered once daily for 8 days. One day after the first treatment of SLY, VA administration was started and continued for 7 days. The levels of serum creatinine and BUN were evaluated using ELISA, caspase enzyme activities and levels of MDA and NO in the kidney tissues were evaluated by the colorimetric methods. The serum BUN, creatinine, NO, MDA levels, and caspase activities were significantly higher in VA group than in control (p < 0.05). However, caspase activities were significantly lower in VA + SLY200 than in VA (p < 0.05). The MDA, serum BUN, and creatinine levels were significantly lower in VA + SLY (50, 100, and 200) groups than in VA group (p < 0.05). VA + SLY200 was found to be the most effective group based on the caspase activities; MDA, NO, serum BUN, creatinine levels; and histopathological findings.
... Studies have shown various mechanisms for VCM-induced renal injury, suggesting that it could be multifactorial, involving several signaling pathways (Qu et al. 2019). VCM-induced apoptosis in LLC-PK1 cells by increasing intracellular ROS generation and by causing mitochondrial membrane depolarization, followed by caspase-9 activation and 3/7 (Arimura et al. 2012). ...
Context
Vancomycin (VCM), an important antibiotic against refractory infections, has been used to treat secondary infections in severe COVID-19 patients. Regrettably, VCM treatment has been associated with nephrotoxicity. Vitamin D3 can prevent nephrotoxicity through its antioxidant effect.
Objective
This study tests the antioxidant effect of vitamin D3 in the prevention of VCM-induced nephrotoxicity.
Materials and methods
Wistar Albino rats (21) were randomly divided into 3 groups: (A) control; (B) VCM 300 mg/kg daily for 1 week; and (C) VCM plus vitamin D3 500 IU/kg daily for 2 weeks. All the rats were sacrificed and serum was separated to determine kidney function parameters. Their kidneys were also dissected for histological examination and for oxidative stress markers.
Results
Lipid peroxidation, creatinine, and urea levels decreased significantly (p < 0.0001) in the vitamin D3-treated group (14.46, 84.11, 36.17%, respectively) compared to the VCM group that was given VCM (MIC<2 μg/mL) only. A significant increase was observed in superoxide dismutase levels in the vitamin D3-treated group (p < 0.05) compared to rats without treatment. Furthermore, kidney histopathology of the rats treated with vitamin D3 showed that dilatation, vacuolization and necrosis tubules decreased significantly (p < 0.05) compared with those in the VCM group. Glomerular injury, hyaline dystrophy, and inflammation improved significantly in the vitamin D3 group (p < 0.001, p < 0.05, p < 0.05, respectively) compared with the VCM group.
Discussion and conclusions
Vitamin D3 can prevent VCM nephrotoxicity. Therefore, the appropriate dose of this vitamin must be determined, especially for those infected with COVID-19 and receiving VCM, to manage their secondary infections.
... Thus, it is a serious problem if patients develop resistance to the drug. Moreover, owing to the narrow treatment index of vancomycin, there is a risk of toxicity, and patients may develop adverse effects such as nephrotoxicity and ototoxicity [4], allergic reactions, renal impairment, or even cardiac arrest [5]. ...
Background
Antibiotic resistance has become a global concern. Vancomycin is known as the last line of antibiotics, but its treatment index is narrow. Therefore, clinical dosing decisions must be made with the utmost care; such decisions are said to be “suitable” only when both “efficacy” and “safety” are considered. This study presents a model, namely the “ensemble strategy model,” to predict the suitability of vancomycin regimens. The experimental data consisted of 2141 “suitable” and “unsuitable” patients tagged with a vancomycin regimen, including six diagnostic input attributes (sex, age, weight, serum creatinine, dosing interval, and total daily dose), and the dataset was normalized into a training dataset, a validation dataset, and a test dataset. AdaBoost.M1, Bagging, fastAdaboost, Neyman–Pearson, and Stacking were used for model training. The “ensemble strategy concept” was then used to arrive at the final decision by voting to build a model for predicting the suitability of vancomycin treatment regimens.
Results
The results of the tenfold cross-validation showed that the average accuracy of the proposed “ensemble strategy model” was 86.51% with a standard deviation of 0.006, and it was robust. In addition, the experimental results of the test dataset revealed that the accuracy, sensitivity, and specificity of the proposed method were 87.54%, 89.25%, and 85.19%, respectively. The accuracy of the five algorithms ranged from 81 to 86%, the sensitivity from 81 to 92%, and the specificity from 77 to 88%. Thus, the experimental results suggest that the model proposed in this study has high accuracy, high sensitivity, and high specificity.
Conclusions
The “ensemble strategy model” can be used as a reference for the determination of vancomycin doses in clinical treatment.
... 81,82 Moreover, it was reported that antibiotic vancomycin inhibited complex I activity and depolarized the mitochondrial membrane of the Lilly Laboratories Culture-Porcine Kidney 1 cells. 83 Mitochondrial damage can be related to the direct interaction of taxane or platinum with the permeability transition pore. The platinum-containing drug cisplatin can generate crosslinks with the voltage-dependent anion channel and ease membrane permeabilization. ...
Mitochondria, which are one of the main organelles of the cell, have vital importance for the body. Mitochondrial mechanisms, which have critical roles in many physiological processes, are active in drug-induced toxic tissue damage as well as in diseases related to mitochondrial dysfunction. Mitochondrial dysfunction is a major mechanism by which various drugs can cause adverse effects in various tissues such as the liver, kidney and heart. Inhibiting respiratory complexes of the electron chain; disrupting cell bioenergetic mechanisms; inducing mitochondrial oxidative stress; inhibiting DNA replication, transcription, or translation; and reduction of protein synthesis are the most common ways drugs harm mitochondria. Mitochondrial transplan-tation has emerged as a promising area that has been studied more frequently in recent years. The importance of mitochondrial transplantation in a variety of mitochondrial dysfunction-related diseases such as cardiovascular diseases, neurodegenerative diseases, and ischemia has been emphasized. The purpose of this review article is to present current information on the role of mitochondria in toxic drug damage and the possible effects of mitochondrial transplantation on toxic damage.
... Although it has potential side effects such as nephrotoxicity, a high dose of vancomycin (every 8-12 h, 15-20 mg/kg body weight) is recommended in the literature [3][4][5] . The molecular mechanism of nephrotoxicity induced by vancomycin is not fully understood, but it is thought to play a role in the pathogenesis of kidney injury by triggering apoptosis, oxidative stress, and inflammation 6,7 . As a result, research into the mechanism of vancomycin-induced nephrotoxicity is required in order to determine how to effectively overcome this antibiotic adverse effect. ...
Purpose: The aim of the study explores probable toxic effects of vancomycin on kidney and analysis of the probable protective effects of melatonin.
Materials and Methods: In this study, rats were randomly divided into 4 groups: the control group; the melatonin (10 mg/kg/day) group; the vancomycin-treated (200 mg/kg) group; and the vancomycin (200 mg/kg) + melatonin (10 mg/kg/day) group. Rats in the treatment group were given two doses of vancomycin a day with an interval of seven consecutive days and melatonin (10 mg/kg/day) once daily for seven consecutive days. The experiment was continued for 15 days. In each group, seven rats were grouped together. 15 days after the experiment, the rats were sacrificed under anesthesia and among all groups. Kidney tissues were collected and processed for further TNF- expression analysis, as well as histological analyses such as hematoxylin and eosin (H&E), Masson's tricrom, and Periodic acid schiff (PAS) staining to assess pathological severity. In addition, a terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay was performed to evaluate apoptosis.
Results: While vancomycin upregulated TNF-α expression, melatonin reduced levels of TNF-α immunoreactivity intensity and clearly improved pathological severity in rat kidneys. Further, melatonin significantly inhibited vancomycin-induced TUNEL-positive cell numbers.
Conclusion: Melatonin has protective activity against vancomycin-induced pro-inflammatory and proapoptotic effects in kidneys during organ preservation time and improves kidney function.
... The recently described amino acid construct, purpurolic acid [15], uniquely combining proline and alanine moieties, is also water soluble, as shown by its original discovery [16] via ion-exchange liquid chromatography for free amino acid quantitation [17]. Proline peptides are becoming of increased pharmaceutical interest on account of their potential for novel structural formulation [18,19], and apoptosis has even been recognised as a side effect of vancomycin in human medicine when used as a therapy to overcome MRSA [20,21]. ...
Complex renal histopathological changes in rats, in silent response to dietary contamination with wheat moulded by a common Penicillium from the Balkans, have long eluded attribution of a causal toxin. So far, water-soluble amphoteric glyco-peptides seem responsible, at least for the nuclear pyknoses in nephron epithelia after several days of dietary exposure. Recently, refined histology analysis has diagnosed pyknosis as apoptosis, and followed the finding through application of medium-pressure liquid chromatography, anion exchange and silica layer chromatography to fractionate a water/alcohol-soluble extract of a fungal fermentation on wheat. Proline was revealed, with other amino acids, in acid hydrolysate of the fermentation extract. Application of mass spectrometry has recognized prominent ions (m/z 550 and 564) correlated with fragmentations consistent with a terminal proline moiety for the putative toxins, coupled with other structural fragments and correlated with apoptosis. Use of 14C-proline in probing Penicillium polonicum fermentation to aid isolation of the new potential toxins, along with application of gel electrophoresis, may further aid characterization of the apoptosis toxin(s). The present focus on proline peptides in mycotoxicosis fits easily with their increasingly recognised pharmacological activity associated with proline’s rigid secondary amine structure, which causes conformational contortion in peptides. Nevertheless, there remains the striking rat renal karyocytomegaly by P. polonicum, for which there is yet no causative mycotoxin.
... Le mécanisme le plus fréquent correspond à l'induction indirecte de lésions spécifiques, notamment via la production de ROS après accumulation lysosomale. Ces ROS vont induire diverses réactions cellulaires, par exemple une dédifférenciation avec dysfonction 59 , l'activation de la production de médiateurs inflammatoires exerçant des effets toxiques 59,84,85 , l'induction d'altérations mitochondriales et du métabolisme 55 ou encore l'induction de phénomènes de mort cellulaire programmée ou non 82,[84][85][86][87] . La lésion peut aussi être secondaire à une action directe de la substance induisant des modifications délétères sur les composants des cellules cibles telle des peroxydations membranaires pour la myoglobine 84 . ...
L’insuffisance rénale aigue (IRA), définie comme une altération brutale de la fonction de filtration rénale, est un véritable problème de santé publique par sa fréquence et son importante morbi-mortalité. La physiopathologie de ce syndrome est encore incomplètement comprise mais elle implique une adaptation métabolique insuffisante de l’épithélium tubulaire rénal dont les mécanismes régulateurs ne sont pas complètement connus. Ce déficit d’adaptation est à l’origine d’une souffrance cellulaire expliquant en partie les lésions tissulaires. De plus, ce syndrome est souvent ignoré ou identifié trop tardivement, en raison de critères diagnostiques imparfaits. Ces lacunes expliquent qu’il n’existe à l’heure actuelle aucun traitement spécifique efficace. Mon travail de thèse s’est organisé autour de ces trois problématiques : physiopathologique, thérapeutique et diagnostique.Le premier axe de mon travail, physiopathologique, a évalué le rôle du facteur de transcription Hepatocyte Nuclear Factor 1 β (HNF-1β) dans la régulation du métabolisme, notamment énergétique, au sein de l’épithélium tubulaire rénal. Nous avons démontré que l’invalidation de ce facteur de transcription dans une lignée tubulaire proximale murine, induit une réorientation du métabolisme énergétique en conditions basales, avec réduction du métabolisme oxydatif mitochondrial et augmentation de la glycolyse, sans d’autre explication que la modulation de PGC-1α. Ces anomalies, proches de celles induites par l’hypoxie dans les cellules sauvages, ne permettent pas d’adaptation supplémentaire des cellules invalidées à un stress. L’invalidation d’Hnf1b induit également des modifications métaboliques au-delà de la production énergétique à l’image de la synthèse des phospholipides, potentiellement en lien avec un régulation directe de la choline kinase-α. Ce travail confirme un rôle d’Hnf1b dans le métabolisme cellulaire énergétique, pouvant expliquer une partie du phénotype des patients souffrant d’une mutation de ce facteur mais le plaçant aussi comme un régulateur de la réponse à l’agression en situation générale Le deuxième axe, thérapeutique, s’est intéressé aux anomalies de la voie de biosynthèse de novo du Nicotinamide Adénine Dinucléotide (NAD) à partir du tryptophane en contexte d’IRA. En comparant, par approche métabolomique ciblée, la composition des urines de patients développant ou non une IRA, après chirurgie cardiaque, nous avons pu confirmer dans un nombre plus important de patients, certaines anomalies observés dans des études antérieures. Néanmoins, à l’inverse d’observations publiées, une supplémentation en nicotinamide, précurseur alternatif de la biosynthèse du NAD, ne permet pas de restaurer le stock intra-rénal de NAD ni d’améliorer les conséquences rénales d’une ischémie-reperfusion chez la souris. Ces résultats incitent à la prudence quant à l’efficacité attendue de ce traitement, en cours d’essai thérapeutique. Le troisième axe, diagnostique, s’est intéressé à l’identification de biomarqueurs urinaires permettant le diagnostic d’une IRA. Nous avons identifié, par approche peptidomique sur des urines prélevées précocement après chirurgie cardiaque, de nombreux peptides différentiellement présents en cas d’IRA. Leur combinaison en une signature permet un diagnostic précoce de l’AKI avec de bonnes performances (AUC = 0.79) dans divers contextes. La poursuite de ces analyses, avec utilisation de nouvelles approches (métabolomique) ou de combinaisons d’approches (multiomics, scores clinico-biologiques), donnent déjà de bons résultats accroissant encore ce bénéfice diagnostique avec même un potentiel prédictif. Bien que préliminaire et difficilement transposable en l’état à la pratique, ce type d’approche offre des perspectives intéressantes dans le diagnostic et la prédiction de cette affection. Ce travail de thèse, a permis de mettre en évidence de nouveaux éléments utiles concernant la physiopathologie, le traitement et le diagnostic de l’IRA.
... Although the exact mechanism of vancomycin-related AKI is not clearly defined, reported preclinical data suggest that vancomycin may cause renal damage by inducing oxidative stress in proximal tubules (12)(13)(14)(15)(16)(17). There are some preclinical studies conducted in mice that have indicated that vancomycin is associated with the downregulation of antioxidant genes and, subsequently, a negative impact on mitochondrial bioenergetics (18)(19)(20). ...
Background: Vancomycin is associated with nephrotoxicity and the mechanism may in part be related to oxidative stress. In vitro and preclinical studies suggest melatonin supplementation decreases oxidative stress. The objective of this study was to evaluate concomitant use of melatonin and vancomycin and the incidence of acute kidney injury (AKI).
Methods: We performed a retrospective cohort study at a large community medical center. All consecutive patients admitted to the medical center between January 2016 and September 2020 who received vancomycin therapy alone or concomitantly with melatonin as part of ordinary care were considered for inclusion. The primary endpoint was the development of AKI defined as an absolute increase in serum creatinine of ≥ 0.3 mg/dL or a ≥ 50% increase in serum creatinine. All data were analyzed using descriptive statistics. A multivariable logistic regression was constructed to account for potential confounding variables.
Results: A total of 303 adult patients meeting inclusion and exclusion criteria treated with vancomycin were identified, 101 of which received melatonin concomitantly. Overall baseline characteristics were similar between the two groups except for the incidence of bactremia/sepsis. After controlling for vancomycin area under the curve, baseline creatinine clearance, and intensive care unit admission in multivariable logistic regression, melatonin use was associated with a 63% decrease in AKI (odds ratio [OR], 0.37; 95% confidence interval [CI], 0.14 – 0.96; p =0.041).
Conclusions: Melatonin use was associated with a significant reduction in vancomycin-related AKI. Although this was a retrospective study with a small sample size, given the magnitude of the difference seen, further large prospective studies are warranted.
... The kidneys of rats on vancomycin have been shown to contain increased levels of malonylodialdehyde, a compound produced by lipid oxidation, and reduced concentrations of anti-oxidative enzymes such as glutathione peroxidase and superoxide dismutase [87]. ROS cause mitochondrial membrane depolarization with the release of cytochrome C, which stimulates the caspaes chain leading to the apoptosis of the cell [88,89]. ROS damage the DNA chain, which stimulates the repair enzyme PARP-1 [90]. ...
Acute kidney injury (AKI) is a global health challenge of vast proportions, as approx. 13.3% of people worldwide are affected annually. The pathophysiology of AKI is very complex, but its main causes are sepsis, ischemia, and nephrotoxicity. Nephrotoxicity is mainly associated with the use of drugs. Drug-induced AKI accounts for 19–26% of all hospitalized cases. Drug-induced nephrotoxicity develops according to one of the three mechanisms: (1) proximal tubular injury and acute tubular necrosis (ATN) (a dose-dependent mechanism), where the cause is related to apical contact with drugs or their metabolites, the transport of drugs and their metabolites from the apical surface, and the secretion of drugs from the basolateral surface into the tubular lumen; (2) tubular obstruction by crystals or casts containing drugs and their metabolites (a dose-dependent mechanism); (3) interstitial nephritis induced by drugs and their metabolites (a dose-independent mechanism). In this article, the mechanisms of the individual types of injury will be described. Specific groups of drugs will be linked to specific injuries. Additionally, the risk factors for the development of AKI and the methods for preventing and/or treating the condition will be discussed.
... 56 Vancomycin has been shown to depolarize the mitochondrial membrane, inhibit the mitochondrial complex I activity, and induce the production of mitochondrial reactive oxygen species in renal and kidney epithelial cells. [98][99][100] In addition, we found a reduction in the glycolytic rate in distal SI organoids after AB treatment and reduced glycolytic capacity in AB-treated proximal and distal SI organoids. The decreased oxygen concentration along the proximal-to-distal small intestine 101 and the changed expression of glucose transporters in the distal SI of ABtreated pups (Supplementary Table 2) might partly be responsible for the observed stronger effect of ABs on distal epithelial cells. ...
Background & Aims
The use of antibiotics (AB) is a common practice during the first months of life. AB can perturb the intestinal microbiota, indirectly influencing the intestinal epithelial cells (IECs), but also directly affect IECs, independent of the microbiota. Previous studies have mostly focused on the impact of AB treatment during adulthood. However, the difference between the adult and neonatal intestine warrants careful investigation of the AB effects in early life.
Methods
Neonatal mice were treated with a combination of amoxicillin, vancomycin, and metronidazole, from postnatal day 10 to 20. Intestinal permeability and whole intestine gene and protein expression were analyzed. IECs were FACS-sorted and their genome-wide gene expression analyzed. Mouse fetal intestinal organoids were treated with the same AB combination and their gene and protein expression, and metabolic capacity determined.
Results
We found that in vivo treatment of neonatal mice led to decreased intestinal permeability and reduced number of specialized vacuolated cells, characteristic of the neonatal period and necessary for absorption of milk macromolecules. Additionally, the expression of genes typically present in the neonatal intestinal epithelium was lower, whereas the adult gene expression signature was higher. Moreover, we found altered epithelial defense and transepithelial sensing capacity. In vitro treatment of intestinal fetal organoids with AB showed that part of the consequences observed in vivo is a result of a direct action of the AB on IECs. Lastly, AB reduced the metabolic capacity of intestinal fetal organoids.
Conclusion
Our results demonstrate that early life AB treatment induces direct and indirect effects on IECs, influencing their maturation and functioning.
... Mitochondrial stress is also induced by these superoxides, leading to the release of cytochrome-C. The latter can lead to apoptosis by caspase activation [47,66]. Alterations in DNA repair has also been described in rats exposed to vancomycin [67]. ...
Background:
Recent studies have identified the combination of vancomycin with piperacillin-tazobactam (VPT) to be associated with increased nephrotoxicity. Multiple, large cohort studies have found this widely used combination to have a higher risk of nephrotoxicity than other regimens in a variety of populations.
Summary:
This review summarizes the epidemiology and clinical features of VPT-associated acute kidney injury (AKI). Potential mechanisms involved in the pathogenesis of this phenomenon are also discussed. Key Message: VPT-associated nephrotoxicity is a recently recognized clinical entity. Clinical strategies to minimize the risk of toxicity in this setting include antimicrobial stewardship, monitoring of kidney function, and emerging data supporting the potential role for novel biomarkers in predicting and managing AKI.
... Clinically relevant doses of bactericidal Abx were shown to cause mitochondrial dysfunction characterized by reduced mitochondrial membrane potential and ATP production, lowered respiration, and increased fission in human epithelial cell lines. This was accompanied by enhanced ROS production, resulting in oxidative tissue damage (Kalghatgi et al., 2013;Kohanski et al., 2016) and apoptosis induction (Arimura et al., 2012). In line, Abx treatment of colon and breast cancer cells resulted in mitochondrial dysfunction and mitophagy induction (Esner et al., 2017;Boyle et al., 2018). ...
Mitochondrial metabolism, dynamics, and stress responses in the intestinal stem cell niche play a pivotal role in regulating intestinal epithelial cell homeostasis, including self-renewal and differentiation. In addition, mitochondria are increasingly recognized for their involvement in sensing the metabolic environment and their capability of integrating host and microbial-derived signals. Gastrointestinal diseases such as inflammatory bowel diseases and colorectal cancer are characterized by alterations of intestinal stemness, the microbial milieu, and mitochondrial metabolism. Thus, mitochondrial function emerges at the interface of determining health and disease, and failure to adapt mitochondrial function to environmental cues potentially results in aberrant tissue responses. A mechanistic understanding of the underlying role of mitochondrial fitness in intestinal pathologies is still in its infancy, and therapies targeting mitochondrial (dys)function are currently lacking. This review discusses mitochondrial signaling and metabolism in intestinal stem cells and Paneth cells as critical junction translating host-and microbe-derived signals into epithelial responses. Consequently, we propose mitochondrial fitness as a hallmark for intestinal epithelial cell plasticity, determining the regenerative capacity of the epithelium.
... reactive oxygen species (ROS) generates in the epithelial cells and activates the oxidative stress response, which leads to DNA damage, cell apoptosis, mitochondrial disorder and cell necrosis (5,6). Use of antioxidants significantly inhibited VCM induced oxidative stress and reduced the incidence of renal toxicity (7,8). ...
Background:
Oxidative stress is one of the possible mechanisms in vancomycin (VCM) induced nephrotoxicity. Some studies suggested that high dose Vitamin C (VC) has protective effect against the nephrotoxicity in mice, but the underlying molecular mechanism is not mentioned. We investigated the potential targets of high dose VC against oxidative stress and inflammation induced by VCM in renal tubular epithelial cells.
Methods:
We conducted an in vitro study using an immortalized proximal tubule epithelial cell line from a normal adult human kidney (HK-2).
Results:
VCM added to HK-2 cells caused an increase of cell death, oxidative stress and expression of inflammatory cytokines. Co-treatment with 0.5 and 1 mM VC attenuated 4-8 mM VCM induced cell death and increased the cell viability to 58-90%. VC significantly decreased lipid peroxidation and increased superoxide dismutase activity. The upregulations of NF-κB, TNF-α and IL-6 in HK-2 cells under 4 mM VCM were also reversed by 0.5 mM VC through the inhibition of oxidative stress.
Conclusions:
This study showed for the first time that VC can attenuate the VCM induced nephrotoxicity by decreasing lipid peroxidation and expression of inflammatory cytokines, and increasing superoxide dismutase 2 (SOD2) activity, this effect may relate to the regulation of ROS/NF-κB pathway.
... Moreover, our findings suggested that VM is an oxidative stress agent in rat tissue, which was confirmed by the enhanced MDA formation associated with a significant depletion of all endogenous antioxidants upon VM injection. Hence, VM induced effects may be triggered by the induction of oxidative stress, The superoxide ion production by VM leads to the depolarization of the mitochondrial membrane potential with a release of cytochrome C and the subsequent activation of both caspases 9 and 3 downstream, and triggered (Arimura et al. 2012). Cytochrome c release catalyzes cardiolipin oxidation in the presence of ROS, which contributes to the permeabilization of mitochondrial membrane. ...
This study evaluated the potential of Punica granatum peel ethanol extract (PPEE) in attenuating the liver and kidney tissue injury induced by vancomycin (VM) treatment in rats. Fifty rats were distributed equally into five groups: control group, PPEE-administered group (100 mg/kg BW/day for 2 weeks; orally), VM-treated group (443.6 mg/kg BW, every alternate day for 2 weeks; intraperitoneally), pre-treated group, and concomitant-treated group. The biochemical response and the histopathology of the hepatic and renal tissue of the treated animals were assessed. The results showed that VM treatment induced substantial hepatotoxicity and nephrotoxicity, evidenced by a significant elevation in tissue injury and lipid oxidative (malondialdehyde) and inflammatory response (C-reactive protein) biomarkers, with lowered antioxidants and protein levels. Additionally, VM treatment induced various morphological, cytotoxic, vascular, and inflammatory perturbations as well as upregulation in the immune-expression of Caspase-3 and downregulation of BCL-2. Moreover, PPEE co-treatment was found to reduce the VM-induced toxicity by protecting the tissue against reactive oxygen species (ROS)–mediated oxidative damage, and inflammation as well as hinder the apoptotic cell death by modulating the expression of apoptosis-related proteins. Thus, we conclude that the PPEE administration showed more restoring efficacy when administered prior to VM medication.
... Therefore, vancomycin induced nephrotoxicity is associated with 5-25% of the patients and this number increases to 25-35% when the antibiotic is taken in combination with aminoglycosides [7][8][9]. Though the molecular mechanism of vancomycin induced nephrotoxicity is not fully understood, oxidative stress, apoptosis, and inflammation are considered to play a role in the pathogenesis of the kidney injury [8,10,11]. Hence, there is a need to investigate the underlying mechanism of vancomycin induced nephrotoxicity to explore the effective management of this side-effect of the antibiotic. Furthermore, the protection of the kidney from vancomycin induced injury is also important to utilize its positive effects. ...
Increased use of vancomycin for treating infections, and the associated risk of causing nephrotoxicity lead to the present study. The antioxidant and anti-apoptotic potential of Silybum marianum is used along with vancomycin to reduce adverse effects on the kidney. Vero cells (monkey kidney cells) and mice were used to test S. marianum extract on vancomycin induced nephrotoxicity. Vero cells were treated with different concentrations of vancomycin and S. marianum for 24 h for determination of cytotoxic potential and mRNA levels of apoptotic genes p53 , p21, and cyt-c were measured. For in-vivo studies mice were divided into five groups; G1 control (untreated), G2 vehicle (olive oil), G3 vancomycin treated (300 mg/kg body weight), G4 (S. marianum; 400 mg/kg bodyweight and vancomycin 300 mg/kg bodyweight simultaneously) and G5 (S. marianum 400 mg/kg bodyweight and vancomycin 300 mg/kg bodyweight treatment started after day 4 of S. marianum treatment). After 10 days histopathological analysis of mice kidneys was performed, serum urea and creatinine were analysed and mRNA expression of p53 , p21, and cyt-c was evaluated. Expression of p53, p21, and cyt-c in Vero cells was elevated in response to vancomycin treatment, whereas after S. marianum administration expression of these genes reduced. Vancomycin showed apoptosis in cells at the concentration of 6 mg/ml (LC50). Urea and creatinine levels in mice were increased in response to vancomycin administration and kidney histology showed an abnormality in functional units. The apoptotic cells were very visible in kidney structure in vancomycin treated group. These symptoms were however relieved in groups where treatment of S. marianum extract was given. mRNA expression of p53 , p21, and cyt-c also reduced in S. marianum treated groups of mice. S. marianum extract has protective effects against renal damage from vancomycin induced oxidative stress and relieves symptoms may be by downregulating apoptotic genes.
... Vancomycin is a tricyclic glycopeptide that is widely administered to patients with Gram-positive infections due to its activity against MDR species, especially MRSA. 1 Nephrotoxicity is considered as a common adverse effect, since it is estimated to complicate 5%-35% of vancomycin courses, depending on the indication, dosing and patients' comorbidities. 2 The pathophysiology of vancomycininduced acute kidney injury (AKI) is multifactorial, as it based on the interplay of increased oxidative stress 3 and mitochondrial dysfunction, 4 leading to ischaemia-reperfusion injury and tubulointerstitial damage. 5 Moreover, a novel cast nephropathy pathogenetic mechanism has been recently proposed, since vancomycin nanospheric aggregates combined with uromodulin were suggested to promote the formation of intratubular obstructive casts. ...
Objectives
Nephrotoxicity represents a major complication of vancomycin administration, leading to high rates of morbidity and treatment failure. The aim of this meta-analysis was to evaluate the association between trough levels and risk of renal impairment, by defining an exposure–toxicity relationship and assessing its accuracy in predicting the development of acute kidney injury (AKI).
Methods
Medline, Scopus, CENTRAL, Clinicaltrials.gov and Google Scholar databases were systematically searched from inception. Studies examining the effects of trough levels on nephrotoxicity risk in adult patients were deemed eligible.
Results
The meta-analysis was based on 60 studies, including 13 304 patients. The development of AKI was significantly linked to both higher initial [standardized mean difference (SMD): 0.82; 95% CI: 0.65–0.98] and maximum (SMD: 1.06; 95% CI: 0.82–1.29) trough levels. Dose–response analysis indicated a curvilinear relationship between trough levels and nephrotoxicity risk (χ2 = 127.1; P value < 0.0001). A cut-off of 15 mg/L detected AKI with a sensitivity of 62.6% (95% CI: 55.6–69.2) and a specificity of 65.5% (95% CI: 58.9–71.6), while applying a 20 mg/L threshold resulted in a sensitivity of 42.9% (95% CI: 34–52.2) and a specificity of 82.5% (95% CI: 73.9–88.8).
Conclusions
The present findings suggest that the development of vancomycin-induced AKI is significantly associated with higher initial and maximum trough levels. An exposure–response relationship was defined, indicating that increasing trough levels correlate with a significant rise of nephrotoxicity risk. Future studies should verify the effectiveness of individualized pharmacokinetic tools that would enable the attainment of trough level targets and minimize the risk of renal toxicity.
... (21) It was recently reported that VCM-induced nephrotoxicity and renal dysfunction are based on free radical injury (23) and that VCM-induced apoptosis occurs in renal tubular cells through the production of mitochondrial ROS and peroxidation of mitochondrial membrane phospholipid. (24,25) Exercise is also known to activate enzymatic reactions in the mitochondria and generate superoxide anion. ...
In the present study, we investigated the beneficial and risky effects of exercise intended to prevent or treat lifestyle-related diseases on insulin sensitivity, lactic acid utilization, lipid metabolism, hepatic and renal oxidative stress, hepatic selenoprotein P and renal function in obese and glucose-intolerant rats with renal failure. We fed normal rats a 20% casein diet while the glucose-intolerant, obese rats received a high-fructose diet, and after then rats received single injection of vancomycin at a dose of 400 mg/kg for constructing the duplicative state of renal failure and diabetes mellitus. They were forced to run for 1 h/day, 6 days/week, for 10 weeks. Exercise reduced visceral fat and ameliorated insulin sensitivity in the high-fructose group, improved lactic acid usage efficiency, however, increased hepatic oxidative stress and complicated renal dysfunction in the normal and high-fructose fed groups with renal failure. Additionally, exercise upregulated hepatic selenoprotein P expression and enhanced renal antioxidative system in both groups. It is concluded that strictly controlled exercise conditions must be adapted to patient health states especially in view of kidney protection, and supplemental therapy is also recommended in parallel with exercise, using nutrients and vitamins for kidney protection.
... Arimura et al. (23) reported that vancomycin caused the increased production of intracellular ROS by the inactivation of mitochondrial complex I in cultured LLC-PK1 cells. Additionally, Sakamoto et al. (24) reported that cardiolipin peroxidation mediates vancomycin-associated intracellular ROS production and the initiation of apoptosis in proximal tubular epithelial cells. ...
Vancomycin is recommended for treating severe infections caused by Gram-positive cocci, including methicillin-resistant Staphylococcus aureus. However, renal damage often occurs as a side effect because vancomycin is mainly excreted via the kidneys. The mechanism of vancomycin-associated nephrotoxicity is thought to involve the elevation of oxidative stress in the kidneys. Vitamin C (VC) has strong antioxidant properties; therefore, we evaluated the effect of high-dose VC preadministration on vancomycin-associated nephrotoxicity. Vancomycin was intraperitoneally injected into mice once daily for 7 d. Additionally, high-dose VC was intraperitoneally injected into mice at 30 min before vancomycin administration for 7 d. The plasma creatinine and urea nitrogen levels were increased by vancomycin treatment; however, high-dose VC preadministration suppressed the increase in these levels. Histological examination also revealed that high-dose VC preadministration reduced the characteristics of vancomycin-associated nephrotoxicity, such as dilated renal tubules with casts, the dilation of renal proximal tubules, and tubular epithelial desquamation. Furthermore, high-dose VC preadministration reduced the appearance of apoptotic cells presumably derived from the epithelial cells in the dilated proximal tubules. Thus, intraperitoneally injected high-dose VC preadministration reduced vancomycin-associated nephrotoxicity in mice. These novel findings may indicate that vancomycin-associated nephrotoxicity in humans may be reduced by high-dose VC preadministration.
... Experimental in vitro studies have shown the underlying pathophysiological principles of vancomycin nephrotoxicity of proximal tubular cells is based on induction of depolarization of the mitochondrial membrane with production of mitochondrial reactive oxygen species (ROS) and peroxidation of mitochondrial phospholipid cardiolipin. The activation of caspase-9 and caspase-3/7 is accompanied by vancomycin-induced apoptotic cell death [27,28]. ...
Substances toxic to the kidney are legion in the modern world. The sheer number and variety, their mutual interactions and, metabolism within the body are a challenge to research. Moreover, the kidney is especially prone to injury owing to its physiology. Acute kidney injury (AKI) induced by poisonous or primarily nephrotoxic substances, may be community acquired with ingestion or inhalation or nosocomial. Many nephrotoxic plants, animal poisons, medications, chemicals and illicit drugs can induce AKI by varying pathophysiological pathways. Moreover, the epidemiology of toxic AKI varies depending on country, regions within countries, socioeconomic status and health care facilities. In this review, we have selected nephrotoxic insults due to medication, plants, animal including snake venom toxicity, environmental, (agri)chemicals and also illicit drugs. We conclude with a section on diagnosis, clinical presentation and management of poisoning accompanied by various organ dysfunction and AKI.
... E. faecalis has evolved numerous virulence factors that ensure its survivability under harsh conditions of including reactive oxygen species (ROS) such as hydrogen peroxide (H 2 O 2 ) inside macrophages [2,3]. The ability of E. faecalis to survive the intolerant ROS condition of the macrophage implies the presence of robust antioxidant systems [4] to which the Alkyl hydroperoxide reductase complex (AhpR) does belong too, which may serve as therapeutic targets for the prevention of early stages of infections [5,6]. ...
The vancomycin-resistant Enterococcus faecalis alkyl hydroperoxide reductase complex (AhpR)with its subunits AhpC (EfAhpC)and AhpF (EfAhpF)is of paramount importance to restore redox homeostasis. Therefore, knowledge about this defense system is essential to understand its antibiotic-resistance and survival in hosts. Recently, we described the crystallographic structures of EfAhpC, the two-fold thioredoxin-like domain of EfAhpF, the novel phenomenon of swapping of the catalytic domains of EfAhpF as well as the unique linker length, connecting the catalytically active N-and C-terminal domains of EfAhpF. Here, using mutagenesis and enzymatic studies, we reveal the effect of an additional third cysteine (C503)in EfAhpF, which might optimize the functional adaptation of the E. faecalis enzyme under various physiological conditions. The crystal structure and solution NMR data of the engineered C503A mutant of the thioredoxin-like domain of EfAhpF were used to describe alterations in the environment of the additional cysteine residue during modulation of the redox-state. To glean insight into the epitope and mechanism of EfAhpF and -AhpC interaction as well as the electron transfer from the thioredoxin-like domain of EfAhpF to AhpC, NMR-titration experiments were performed, showing a coordinated disappearance of peaks in the thioredoxin-like domain of EfAhpF in the presence of full length EfAhpC, and indicating a stable EfAhpF-AhpC-complex. Combined with docking studies, the interacting residues of EfAhpF were identified and a mechanism of electron transfer of the EfAhpF donor to the electron acceptor EfAhpC is described.
... Mitochondrial toxicity has been proposed also for other recognized nephrotoxic antibiotics as aminoglycosides (Davey et al., 1970) and vancomycin (Arimura et al., 2012). We assessed the impact of gentamycin (a member of the aminoglycoside family) and vancomycin on mitochondrial membrane potential in comparison with colistin. ...
... These compounds, as well as VCM, perturb proximal renal tubule epithelial cells that are the sites of reabsorption (6). The affects attributed to VCM involve renal tubular cell apoptosis through an increase in mitochondrial superoxide production, leading to a loss of mitochondrial membrane potential and elevated caspase activity (13). The filtration and energy transport mechanisms in the proximal tubule epithelia render the kidney highly susceptible to toxicant-induced renal injury (14). ...
Nephrotoxicity is the major limiting factor for the clinical use of vancomycin (VCM) for treatment of serious infections caused by multiresistant Gram-positive bacteria. This study investigated the renal protective activity of rutin in a rat model of VCM-induced kidney injury in male Wistar rats. VCM administered intraperitoneally at 200 mg/kg twice daily for 7 successive days resulted in significant elevation of blood urea nitrogen and creatinine, as well as urinary N -acetyl-β-D-glucosaminidase. Coadministration of VCM with oral rutin at 150 mg/kg significantly reduced these markers of kidney damage. Rutin also significantly attenuated VCM-induced oxidative stress, inflammatory cell infiltration, apoptosis, and decreased interleukin-1β and tumor necrosis factor alpha levels (all P < 0.05 or 0.01) in kidneys. Renal recovery from VCM injury was achieved by rutin through increases in Nrf2 and HO-1 and a decrease in NF-κB expression. Our results demonstrated a protective effect of rutin on VCM-induced kidney injury through suppression of oxidative stress, apoptosis, and downregulation of the inflammatory response. This study highlights a role for oral rutin as an effective intervention to ameliorate nephrotoxicity in patients undergoing VCM therapy.
Ethnopharmacological relevance:
Panacis Quinquefolii Radix (PQR) is often illegally sulfur fumigated to extend shelf life and improve appearance, but existing regulations of detecting SO2 residues do not accurately identify desulfurized sulfur-fumigated PQR (SF-PQR). Although sulfur-containing derivatives (SCDs) have been reported in some sulfur-fumigated herbs, there is a lack of research on the generation mechanisms and toxicity of SCDs. Our previous study reported the nephrotoxicity of SF-PQR, and there is an urgent necessity to illuminate the mechanism of toxicity as well as its association with SCDs.
Aim of the study:
To investigate the transformation pattern of chemical components and SCDs in SF-PQR, and to disclose the linkage between SCDs and SF-PQR nephrotoxicity.
Materials and methods:
The extracts of PQR (before and after SF) were detected by the UPLC-LTQ-Orbitrap-MS method, and SCDs were screened as quality markers (Q-markers). The composition of sulfur combustion products was examined by ion chromatography to exploit the conversion mechanism of SCDs. After administration of PQR extracts to mice for two weeks, serum was collected for GC-MS-based untargeted metabolomics study to mine for differential metabolites. The upstream genes were traced by network analysis to probe toxicity targets. Molecular docking was used to uncover the interactions between SCDs and the targets.
Results:
Thirty-three compounds were identified and 11 SCDs of saponins were screened, including four SO3 sulfonation products and five H2SO3 sulfonation products. Metabolomics study showed significant alterations in serum biochemistry of SF-PQR group, with substantial increases in fumarate and 2-heptanone content, and induced disturbances in glycerolipid metabolism and phenylalanine, tyrosine, and tryptophan biosynthesis in mice. Network analysis revealed that the key toxicity targets were DECR1, PLA2G1B, and CAT. Molecular docking indicated that SCDs had stable interaction forces with the above three toxicity targets.
Conclusion:
SF-PQR caused kidney damage by affecting glycerolipid metabolism and phenylalanine, tyrosine, and tryptophan biosynthesis. Eleven SCDs were potential nephrotoxic substances and Q-markers for identifying SF-PQR. This study is the first to systematically elucidate the mechanism of SF-PQR-related nephrotoxicity, providing a robust basis for the construction of new quality control standards and a global prohibition of sulfur fumigation.
Purpose:
The combination of vancomycin and piperacillin/tazobactam (VAN + PTZ) provides a broad spectrum of activity against multiple pathogens. However, a major issue in previous research concerned significant nephrotoxicity associated with this drug combination, and most studies have been conducted in American and European countries, with no similar data available from China. Therefore, this study evaluated the nephrotoxic effects of VAN + PTZ in a large-scale Chinese cohort to determine the prevalence of acute kidney injury (AKI) in this population by comparing PTZ and vancomycin monotherapies and the combined use of vancomycin and β-lactam antibiotics.
Methods:
This retrospective cohort study identified adult patients who received vancomycin either as monotherapy or in combination with PTZ or carbapenem (VAN + CAR) for at least 48 hours at Jiangsu Province Hospital from January 1, 2017, to December 31, 2018. Patients were also evaluated for the development of AKI, defined according to the Kidney Disease Improving Global Outcome criteria. Duration of vancomycin exposure, steady-state trough vancomycin concentrations, and other risk factors for AKI were assessed. A Bayesian network meta-analysis was conducted to validate our results and comparatively evaluate the nephrotoxicity of β-lactam antibiotics in combination with vancomycin.
Findings:
In all, 752 patients were included in the present study. The prevalence of AKI was higher in the VAN + PTZ group than in the VAN and VAN + CAR groups (15.2% vs 4.0% and 6.0%, respectively). After adjustment for confounding factors, VAN + PTZ was still related to AKI (odds ratio [OR] = 4.37; 95% CI, 1.65-11.59; P = 0.003). The network meta-analysis indicated that VAN + PTZ was associated with a significantly higher risk for AKI than was VAN (OR = 3.23; 95% CI, 2.50-4.35), PTZ (OR = 2.86; 95% CI, 1.92-4.12), VAN + cefepime (FEP) (OR = 2.37; 95% CI, 1.80-3.19), or VAN + CAR (OR = 2.28; 95% CI, 1.64-3.21). However, there was no significant difference with respect to AKI prevalence among the VAN, PTZ, VAN + FEP, and VAN + CAR groups.
Implications:
The prevalence of AKI was higher with VAN + PTZ therapy than with VAN or PTZ monotherapy or with the concurrent use of VAN and FEP or CAR in our study. Clinicians should adequately assess renal function and consider this differential risk for nephrotoxicity when choosing empiric antibiotics in hospitalized patients to minimize the rates of AKI.
Vancomycin is a glycopeptide antibiotic used against multi-drug resistant gram-positive bacteria such as Staphylococcus aureus (MRSA). Although invaluable against resistant bacteria, vancomycin harbors adverse drug reactions including cytopenia, ototoxicity, as well as nephrotoxicity. Since nephrotoxicity is a rarely occurring side effect, its mechanism is incompletely understood. Only recently, the actual clinically relevant concentration the in kidneys of patients receiving vancomycin was investigated and were found to exceed plasma concentrations by far. We applied these clinically relevant vancomycin concentrations to murine and canine renal epithelial cell lines and assessed metabolic and lipidomic alterations by untargeted and targeted gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry analyses. Despite marked differences in the lipidome, both cell lines increased anabolic glucose reactions, resulting in higher sorbitol and lactate levels. To the best of our knowledge, this is the first endometabolic profiling of kidney cells exposed to clinically relevant vancomycin concentrations. The presented study will provide a valuable dataset to nephrotoxicity researchers and might add to unveiling the nephrotoxic mechanism of vancomycin.
Cardiolipin (CL) is a key phospholipid responsible for mitochondrial function and cristae integrity. The CL level is associated with various diseases characterized by mitochondrial dysfunction, including ischemic heart diseases and cancer. CL is an attractive target for mitochondria-specific drugs, but unnecessary interaction with CL might lead to detrimental side effects such as heart failure and kidney dysfunction. Thus, a simple and robust method for CL quantification and a reliable assay for the determination of drug affinity for CL are desired. We report a new fluorescent CL-specific probe with impressive photophysical properties that allows CL quantification in mitochondrial fractions isolated from cell and tissue homogenates and enables estimates of drug affinity for CL in the first fluorescence-based competitive binding assay. It was found that CL concentration is elevated in mitochondrial fractions isolated from cancer cells and cells with high proliferation rate (up to 108.5 ± 16.0 nmol/mg prot in mouse colon carcinoma cells, CT-26). CL concentration in mitochondria from brain tissue (66.11 ± 5.78 nmol/mg prot) is circa twice higher than in heart and kidney mitochondria (37.49 ± 8.69 and 33.95 ± 5.32 nmol/mg prot, respectively.) Generally, positively charged substances bind with CL, but their affinity is highly variable with EC50 values ranging from sub-micromolar to millimolar concentration.
Vancomycin (VCM) is an effective chemotherapeutic agent commonly used against gram‐positive microorganisms but has serious nephrotoxic side effects that limit its effectiveness. New therapeutics and strategies are urgently needed to combat VCM associated nephrotoxicity. In this study, we determined the protective effect of chlorogenic acid (CA) in a rat model of VCM‐induced nephrotoxicity. VCM administration led to markedly elevated blood urea nitrogen and serum creatinine levels that could be prevented with CA co‐administration. VCM‐mediated oxidative stress was also significantly attenuated by CA as reflected by decreased malondialdehyde and nitric oxide in VCM‐treated kidneys. CA administration also prevented the VCM‐mediated decrease in the renal antioxidative enzyme activities of glutathione reductase, glutathione peroxidase, and catalase and led to increased levels of reduced glutathione that had been depleted by VCM. Moreover, CA administration clearly inhibited VCM‐induced expression of nuclear factor‐kappa B, inducible nitric oxide synthase and the downstream pro‐inflammatory mediators tumor necrosis factor‐α and interleukins 1β and 6. Apoptotic markers were also markedly down‐regulated with CA. Overall, CA treatment mitigated VCM‐induced oxidative and nitrosative stresses and countered the apoptotic and inflammatory effects of VCM. Notably, CA did not affect the antibacterial activity of VCM in vitro.
Vancomycin is a recommended therapy in multiple national guidelines. Despite the common use, there is a poor understanding of the mechanistic drivers and potential modifiers of vancomycin‐mediated kidney injury. In this review, historic and contemporary rates of vancomycin‐induced kidney injury (VIKI) are described, and toxicodynamic models and mechanisms of toxicity from preclinical studies are reviewed. Aside from known clinical covariates that worsen VIKI, preclinical models have demonstrated that various factors impact VIKI, including dose, route of administration, and thresholds for pharmacokinetic parameters. The degree of acute kidney injury (AKI) is greatest with the intravenous route and higher doses that produce larger maximal concentrations and areas under the concentration curve. Troughs (i.e., minimum concentrations) have less of an impact. Mechanistically, preclinical studies have identified that VIKI is a result of drug accumulation in proximal tubule cells, which triggers cellular oxidative stress and apoptosis. Yet, there are several gaps in the knowledge which may represent viable targets to make vancomycin therapy less toxic. Potential strategies include prolonging infusions and lowering maximal concentrations, administration of antioxidants, administering agents that decrease cellular accumulation, and reformulating vancomycin to alter the renal clearance mechanism. Based on preclinical models and mechanisms of toxicity, we propose potential strategies to lessen VIKI.
Aim:Use of combination antibiotics piperacillin-tazobactam (PTZ) and vancomycin (VAN) is so often used as “top guns” for severe infections in hospitalized patients. VAN’s nephrotoxicity is well-known. PTZ has been seen to prolong increased creatinine levels. Reports have surfaced higher rates of acute kidney injury (AKI) among patients treated with combination of PTZ + VAN in the literature. The purpose of this study was to compare the prevalence of AKI with the use of VAN alone and combination of PTZ + VAN treatment at our institution. Our hypothesis was that the combination of PTZ + VAN would be associated with higher prevalence of AKI compared with VAN only.Materials and Methods:We performed this study to compare the combination of PTZ + VAN and VAN alone in critically ill patients in our hospital from 2016 to 2018. Included patients were stratified by treatment with PTZ + VAN and VAN alone.Results:A total of 113 patients were included who were treated with PTZ + VAN and VAN alone. Patient demographics, comorbidities, sites of infection, and duration for 48 hours were compared. We found that PTZ + VAN was better than VAN alone in terms of AKI.Conclusion:The combination of VAN plus PTZ is better use to prevent AKI over VAN monotherapy. Further research in the critically ill population is needed. Recent literature has suggested that the concomitant use of PTZ and VAN is associated with a higher risk of AKI compared with the use of VAN alone. Our study suggested that patients getting combination therapy were sicker hence receiving it as an empiric therapy and it is required to look at the possibility of residual confounding in previous studies.
Background and objectives
Acute kidney injury represents a major complication of vancomycin treatment, especially when it is co-administered with other nephrotoxins. This meta-analysis aims to comparatively assess the nephrotoxicity of antipseudomonal beta-lactams when combined with vancomycin.
Data Sources
Medline, Scopus, CENTRAL and Clinicaltrials.gov databases were systematically searched from inception through 20 August 2019.
Study eligibility criteria
Studies evaluating acute kidney injury risk following the concurrent use of antipseudomonal beta-lactams and vancomycin were selected.
Participants
Adult and pediatric patients treated in hospital or intensive care unit.
Intervention
Administration of vancomycin combined with any antipseudomonal beta-lactam.
Methods
Acute kidney injury incidence was defined as the primary outcome. Secondary outcomes included severity, onset, duration, need of renal replacement therapy, length of hospitalization and mortality. Quality of evidence was assessed using the ROBINS-I tool and the Confidence In Network Meta-Analysis approach.
Results
Forty-seven cohort studies were included, with a total of 56,984 patients. In the adult population, the combination of piperacillin-tazobactam and vancomycin resulted in significantly higher nephrotoxicity rates compared to vancomycin monotherapy (Odds ratio-OR: 2.05, 95% confidence intervals-CI [1.17-3.46]) and its concurrent use with meropenem (OR: 1.84, 95% CI [1.02-3.10]) or cefepime (OR: 1.80, 95% CI [1.13-2.77]). In pediatric patients, acute kidney injury was significantly higher with vancomycin plus piperacillin-tazobactam than vancomycin alone (OR: 4.18, 95% CI [1.01-17.29]) or vancomycin plus cefepime OR: 3.71, 95% CI [1.08-11.24]). No significant differences were estimated for the secondary outcomes. Credibility of outcomes was judged as moderate, mainly due to imprecision and inter-study heterogeneity.
Conclusions
The combination of vancomycin and piperacillin-tazobactam is associated with higher acute kidney injury rates compared to its parallel use with meropenem or cefepime. Current evidence is exclusively observational and is limited by inter-study heterogeneity. Randomized controlled trials are needed to verify these results and define preventive strategies to minimize nephrotoxicity risk.
Background:
Vancomycin and piperacillin/tazobactam are reported in clinical studies to increase acute kidney injury (AKI). However, no clinical study has demonstrated synergistic toxicity, only that serum creatinine increases.
Objectives:
To clarify the potential for synergistic toxicity between vancomycin, piperacillin/tazobactam and vancomycin + piperacillin/tazobactam treatments by quantifying kidney injury in a translational rat model of AKI and using cell studies.
Methods:
(i) Male Sprague-Dawley rats (n = 32) received saline, vancomycin 150 mg/kg/day intravenously, piperacillin/tazobactam 1400 mg/kg/day intraperitoneally or vancomycin + piperacillin/tazobactam for 3 days. Urinary biomarkers and histopathology were analysed. (ii) Cellular injury was assessed in NRK-52E cells using alamarBlue®.
Results:
Urinary output increased from Day -1 to Day 1 with vancomycin but only after Day 2 for vancomycin + piperacillin/tazobactam-treated rats. Plasma creatinine was elevated from baseline with vancomycin by Day 2 and only by Day 4 for vancomycin + piperacillin/tazobactam. Urinary KIM-1 and clusterin were increased with vancomycin from Day 1 versus controls (P < 0.001) and only on Day 3 with vancomycin + piperacillin/tazobactam (P < 0.001, KIM-1; P < 0.05, clusterin). The histopathology injury score was elevated only in the vancomycin group when compared with piperacillin/tazobactam as a control (P = 0.04) and generally not so with vancomycin + piperacillin/tazobactam. In NRK-52E cells, vancomycin induced cell death with high doses (IC50 48.76 mg/mL) but piperacillin/tazobactam did not, and vancomycin + piperacillin/tazobactam was similar to vancomycin.
Conclusions:
All groups treated with vancomycin demonstrated AKI; however, vancomycin + piperacillin/tazobactam was not worse than vancomycin. Histopathology suggested that piperacillin/tazobactam did not worsen vancomycin-induced AKI and may even be protective.
Vancomycin is a glycopeptide antibiotic widely used to treat infections caused by methicillin‐resistant Staphylococcus aureus. However, nephrotoxicity is a major adverse side effect, and the development of effective nephroprotective agents remains a priority in antimicrobial chemotherapy. In this study, we investigated the cell protective effects of the flavonol glycoside rutin against vancomycin‐induced toxicity. Vancomycin added to porcine renal tubular LLC‐PK1 cells caused an increase of production of intracellular reactive oxygen species and subsequent apoptotic cell death. Pretreatment of LLC‐PK1 cells with rutin at 5, 10, and 20 μM for 2 hr prior to 2‐mM vancomycin exposure for 24 hr significantly decreased intracellular reactive oxygen species and increased superoxide dismutase and catalase activities. Rutin pretreatment also protected cells from vancomycin‐induced caspase activation, mitochondrial membrane depolarization, and subsequent apoptosis. This study demonstrates a protective effect of rutin and suggests that rutin coadministration is an alternative therapy for treatment of vancomycin‐induced nephrotoxicity.
Introduction
Vancomycin and piperacillin tazobactam (VAN+TZP) are two of the most commonly utilized antibiotics in the hospital setting and are reported in clinical studies to increase acute kidney injury (AKI). However, no clinical study has demonstrated that synergistic toxicity occurs, only that serum creatinine (SCr) increases with VAN+TZP. The purpose of this study was to assess biologic plausibility by quantifying kidney injury between VAN, TZP, and VAN+TZP treatments using a translational rat model of AKI and rat kidney epithelial cell studies.
Methods
(i) Male Sprague-Dawley rats (n=32) received either saline, VAN 150 mg/kg/day intravenously, TZP 1400 mg/kg/day via intraperitoneal injection, or VAN+TZP. Animals were placed in metabolic cages pre-study and on drug dosing days 1-3. Urinary biomarkers and histopathology were analyzed. (ii) Cellular injury of VAN+TZP was assessed in serum-deprived rat kidney cells (NRK-52E) using an alamarBlue® viability assay. Cells were incubated with antibiotics VAN, TZP, cefepime, and gentamicin alone or combined with the same drugs plus VAN 1 mg/mL.
Results
In the VAN-treated rats, urinary KIM-1 and clusterin were increased on days 1, 2, and 3 compared to controls (P<0.001). Elevations were seen only after 3 days of treatment with VAN+TZP (P<0.001 KIM-1, P<0.05 clusterin). Histopathology was only elevated in the VAN group when compared to TZP as a control (P=0.04). Results were consistent across biomarkers and histopathology suggesting that adding TZP did not worsen VAN induced AKI and may even be protective. In NRK-52E cells, VAN alone caused moderate cell death with high doses (IC 50 48.76 mg/mL). TZP alone did not cause cellular death under the same conditions. VAN+TZP was not different from VAN alone in NRK-52E cells (P>0.2).
Conclusions
VAN+TZP does not cause more kidney injury than VAN alone in a rat model of VIKI or in rat kidney epithelial cells.
Many agents, which are crucial for diagnostic and therapeutic purposes, are associated with nephrotoxicity and acute kidney injury. The nephrotoxicity often becomes the limiting factor for use of these agents, and, in some cases, there are no alternative agents. This chapter reviews the common classes of agents that are associated with nephrotoxicity (contrast, intravenous immunoglobulin, aminoglycosides, vancomycin, amphotericin, and nonsteroidal anti-inflammatory drugs). The mechanisms of nephrotoxicity from these agents as well various patient risk factors associated with nephrotoxicity are examined, and potential strategies to try to prevent acute kidney injury are reviewed. There are many therapeutic agents that cause renal toxicity that often become the limiting factor in the agent’s use. Often, there are no alternative agents available, so recognition of the risk factors for nephrotoxicity and incorporation of preventative measures are critical.
Vancomycin hydrochloride (VCM) is a glycopeptide antibiotic that is commonly used to eradicate methicillin-resistant gram-positive cocci, despite its nephrotoxic side effects. Elderly people are particularly susceptible to developing VCM-induced nephrotoxicity. However, the precise mechanism by which VCM induces nephrotoxicity in elderly people is not completely understood. Therefore, we investigated VCM-induced nephrotoxicity in mice of different ages. VCM was injected intraperitoneally into mice at 1, 3, 6, 12, and 24 months of age at a dosage of 400 mg/kg body weight for 3 and 14 days. Twenty-four hours after the last injection, we examined plasma creatinine levels and histopathological alterations in the kidneys. VCM administration increased plasma creatinine levels, and these values gradually increased to higher levels with aging. The histological examination revealed renal tubular degeneration, such as brush-border atrophy, apoptosis/necrosis of the tubular epithelium, and epithelial desquamation, that gradually became more severe with aging. Furthermore, immunohistochemical staining with anti-CD10 and anti-single-stranded DNA antibodies revealed damaged renal proximal tubules with marked dilatation, as well as numerous apoptotic cells, and these features increased in severity in 12- and 24-month-old mice receiving VCM. Based on these results, aged mice were highly susceptible to kidney damage induced by VCM administration. In addition, proximal tubular epithelial cells likely underwent apoptosis after the administration of VCM. This report is the first to document VCM-induced nephrotoxicity in mice of different ages. Thus, this mouse model could be useful for understanding the mechanisms of VCM-induced nephrotoxicity in the elderly.
The aims of this study were to examine vancomycin (VCM)-induced oxidative stress that promotes production of reactive oxygen species (ROS) and to investigate the role of erdosteine, an expectorant agent, which has also antioxidant properties, on kidney tissue against the possible VCM-induced renal impairment in rats. Rats were divided into three groups: sham, VCM and VCM plus erdosteine. VCM was administrated intraperitoneally (i.p.) with 200 mg kg−1 twice daily for 7 days. Erdosteine was administered orally. VCM administration to control rats significantly increased renal malondialdehyde (MDA) and urinary N-acetyl-β-d-glucosaminidase (NAG, a marker of renal tubular injury) excretion but decreased superoxide dismutase (SOD) and catalase (CAT) activities. Erdosteine administration with VCM injections caused significantly decreased renal MDA and urinary NAG excretion, and increased SOD activity, but not CAT activity in renal tissue when compared with VCM alone. Erdosteine showed histopathological protection against VCM-induced nephrotoxicity. There were a significant dilatation of tubular lumens, extensive epithelial cell vacuolization, atrophy, desquamation, and necrosis in VCM-treated rats more than those of the control and the erdosteine groups. Erdosteine caused a marked reduction in the extent of tubular damage. It is concluded that oxidative tubular damage plays an important role in the VCM-induced nephrotoxicity and the modulation of oxidative stress with erdosteine reduces the VCM-induced kidney damage both at the biochemical and histological levels.
Cholesterol secoaldehyde (ChSeco), a putative product of the reaction of ozone with cholesterol in aqueous environments, has been shown to induce apoptosis in H9c2 cardiomyoblasts. This study further investigated the involvement of apoptotic-related proteins and gene expression using RT-PCR, Western blot, and appropriate biochemical assays. The RT-PCR analysis revealed that ChSeco activates the expression of genes involved in the death receptor (extrinsic) pathway. The significance of this pathway was also evident from the increased activity of caspase-8. The overexpression of Apaf-1, loss of mitochondrial transmembrane potential, release of cytochrome c, and increased activity of caspase-9 provide further evidence for the involvement of a mitochondrial (intrinsic) pathway. Time-course analysis of ChSeco-exposed H9c2 cells showed an upstream increase in the generation of reactive oxygen species (ROS) and an associated decrease in the intracellular glutathione. N-acetyl-L-cysteine and Trolox significantly attenuated the ChSeco-induced ROS formation and cytotoxicity and also down-regulated the expression of the genes of all the players in either pathway. This study clearly shows that ChSeco induces apoptosis in H9c2 cells through ROS generation and the activation of both the intrinsic and the extrinsic pathway.
Production of reactive oxygen species (ROS) by the mitochondrial respiratory chain is considered to be one of the major causes
of degenerative processes associated with oxidative stress. Mitochondrial ROS has also been shown to be involved in cellular
signaling. It is generally assumed that ubisemiquinone formed at the ubiquinol oxidation center of the cytochrome bc1 complex is one of two sources of electrons for superoxide formation in mitochondria. Here we show that superoxide formation
at the ubiquinol oxidation center of the membrane-bound or purified cytochrome bc1 complex is stimulated by the presence of oxidized ubiquinone indicating that in a reverse reaction the electron is transferred
onto oxygen from reduced cytochrome bL via ubiquinone rather than during the forward ubiquinone cycle reaction. In fact, from mechanistic studies it seems unlikely
that during normal catalysis the ubisemiquinone intermediate reaches significant occupancies at the ubiquinol oxidation site.
We conclude that cytochrome bc1 complex-linked ROS production is primarily promoted by a partially oxidized rather than by a fully reduced ubiquinone pool.
The resulting mechanism of ROS production offers a straightforward explanation of how the redox state of the ubiquinone pool
could play a central role in mitochondrial redox signaling.
Generation of reactive oxygen species (ROS) causes cellular oxidative damage and has been implicated in the etiology of Alzheimer's disease (AD). In contrast, multiple lines of evidence indicate that ROS can normally modulate long-term potentiation (LTP), a cellular model for memory formation. We recently showed that decreasing the level of superoxide through the overexpression of mitochondrial superoxide dismutase (SOD-2) prevents memory deficits in the Tg2576 mouse model of AD. In the current study, we explored whether AD-related LTP impairments could be prevented when ROS generation from mitochondria was diminished either pharmacologically or via genetic manipulation. In wild-type hippocampal slices treated with exogenous amyloid β peptide (Aβ1-42) and in slices from APP/PS1 mutant mice that model AD, LTP was impaired. The LTP impairments were prevented by MitoQ, a mitochondria-targeted antioxidant, and EUK134, an SOD and catalase mimetic. In contrast, inhibition of NADPH oxidase either by diphenyliodonium (DPI) or by genetically deleting gp91(phox), the key enzymatic component of NADPH oxidase, had no effect on Aβ-induced LTP blockade. Moreover, live staining with MitoSOX Red, a mitochondrial superoxide indicator, combined with confocal microscopy, revealed that Aβ-induced superoxide production could be blunted by MitoQ, but not DPI, in agreement with our electrophysiological findings. Finally, in transgenic mice overexpressing SOD-2, Aβ-induced LTP impairments and superoxide generation were prevented. Our data suggest a causal relationship between mitochondrial ROS imbalance and Aβ-induced impairments in hippocampal synaptic plasticity.
The signal transducer and activator of transcription 3 (STAT3) is a transcription factor and downstream product of cytokine
and growth factor pathways. Among members of the STAT family, STAT3 has garnered particular interest due to its role in cancer
and development. Recently, it was proposed that STAT3 regulates cardiac ATP generation in vivo through protein interaction with the mitochondrial complexes of oxidative phosphorylation, specifically Complexes I/II. For
this mechanism to work effectively, the cellular ratio of Complexes I/II and STAT3 must approach one. However, using three
different proteomic approaches in cardiac tissue, we determined the ratio of Complexes I/II and STAT3 to be ∼105. This finding suggests that direct protein interaction between Complexes I/II and STAT3 cannot be required for optimal ATP
production, nor can it dramatically modulate oxidative phosphorylation in vivo. Thus, STAT3 is likely altering mitochondrial function via transcriptional regulation or indirect signaling pathways that
warrant further investigation.
Oxidative stress and increased release of reactive oxygen species (ROS) are associated with apoptosis induction. Here we report ROS-mediated induction of apoptosis by xanthohumol (XN) from hops. XN at concentrations of 1.6-25 microM induced an immediate and transient increase in superoxide anion radical (O(2)(-*)) formation in 3 human cancer cell lines (average+/-SD EC(50) of maximum O(2)(-*) induction=3.1+/-0.8 microM), murine macrophages (EC(50)=4.0+/-0.3 microM), and BPH-1 benign prostate hyperplasia cells (EC(50)=4.3+/-0.1 microM), as evidenced by the O(2)(-*)-specific indicator dihydroethidium. MitoSOX Red costaining and experiments using isolated mouse liver mitochondria (EC(50)=11.4+/-1.8 microM) confirmed mitochondria as the site of intracellular O(2)(-*) formation. Antimycin A served as positive control (EC(50)=12.4+/-0.9 microM). XN-mediated O(2)(-*) release was significantly reduced in BPH-1 rho(0) cells harboring nonfunctional mitochondria (EC(50)>25 microM) and by treatment of BPH-1 cells with vitamin C, N-acetylcysteine (NAC), or the superoxide dismutase mimetic MnTMPyP. In addition, we demonstrated a rapid 15% increase in oxidized glutathione and a dose-dependent overall thiol depletion within 6 h (IC(50)=24.3+/-11 microM). Respiratory chain complexes I-III were weakly inhibited by XN in bovine heart submitochondrial particles, but electron flux from complex I and II to complex III was significantly inhibited in BPH-1 cells, with IC(50) values of 28.1 +/- 2.4 and 24.4 +/- 5.2 microM, respectively. Within 15 min, intracellular ATP levels were significantly reduced by XN at 12.5 to 50 microM concentrations (IC(50)=26.7+/-3.7 microM). Concomitantly, XN treatment caused a rapid breakdown of the mitochondrial membrane potential and the release of cytochrome c, leading to apoptosis induction. Pre- or coincubation with 2 mM NAC and 50 microM MnTMPyP at various steps increased XN-mediated IC(50) values for cytotoxicity in BPH-1 cells from 6.7 +/- 0.2 to 12.2 +/- 0.1 and 41.4 +/- 7.6 microM, and it confirmed XN-induced O(2)(-*) as an essential trigger for apoptosis induction. In summary, we have identified mitochondria as a novel cellular target of XN action, resulting in increased O(2)(-*) production, disruption of cellular redox balance and mitochondrial integrity, and subsequent apoptosis.
Bcl-2 has been shown to promote survival of cancer cells by maintaining a slight pro-oxidant state through elevated mitochondrial respiration during basal conditions. On oxidative stress, Bcl-2 moderates mitochondrial respiration through cytochrome c oxidase (COX) activity to prevent an excessive buildup of reactive oxygen species (ROS) by-production from electron transport activities. However, the underlying molecular mechanism(s) of Bcl-2-mediated ROS regulation and its impact on carcinogenesis remain unclear. In this study, we show that Bcl-2 expression positively influences the targeting of nuclear-encoded COX Va and Vb to the mitochondria of cancer cells. In addition, evidence is presented in support of a protein-protein interaction between COX Va and Bcl-2, involving the BH2 domain of Bcl-2. Interestingly, episodes of serum withdrawal, glucose deprivation or hypoxia aimed at inducing early oxidative stress triggered Bcl-2-overexpressing cells to preserve mitochondrial levels of COX Va while depressing COX Vb, whereas the reverse was observed in mock-transfected cells. The unique manner in which Bcl-2 adjusted COX subunits during these physiological stress triggers had a profound impact on the resultant decrease in COX activity and maintenance of mitochondrial ROS levels, thus delineating a novel mechanism for the homeostatic role of Bcl-2 in the redox biology and metabolism of cancer cells.
Data suggest that higher doses of vancomycin can increase the risk of nephrotoxicity. No study has been undertaken to determine the pharmacodynamic index (ie, the area under the curve [AUC] or the trough value) that best describes the relationship between vancomycin exposure and onset of nephrotoxicity.
A retrospective study was conducted among patients who received vancomycin for a suspected or proven gram-positive infection during the period from 1 January 2005 through 31 December 2006 at Albany Medical Center Hospital. Patients were included in our study if they (1) were > or =18 years old, (2) had an absolute neutrophil count of > or =1000 cells/mm(3), (3) received vancomycin for >48 h, (4) had 1 vancomycin trough level collected within 96 h of vancomycin therapy, and (5) had a baseline serum creatinine level of <2.0 mg/dL. Patients were excluded if they (1) had a diagnosis of cystic fibrosis, (2) received intravenous contrast dye within 7 days of starting vancomycin or during therapy, or (3) required vasopressor support during therapy. Demographics, comorbid conditions, and treatment data were collected. The highest observed vancomycin trough value within 96 h of initiation of vancomycin therapy and the estimated vancomycin AUC were analyzed as measures of vancomycin exposure. The vancomycin AUC value from 0 to 24 h at steady state (in units of mg x h/L) for each patient was estimated by use of the maximum a posteriori probability Bayesian procedure in ADAPT II. Nephrotoxicity was defined as an increase in serum creatinine level of 0.5 mg/dL or 50%, whichever was greater, following initiation of vancomycin therapy. Logistic and Cox proportional hazards regression models identified the vancomycin pharmacodynamic index that best describes the relationship between vancomycin exposure and toxicity.
During the study period, 166 patients met the inclusion criteria. Both initial vancomycin trough values and 0-24-h at steady state AUC values were associated with nephrotoxicity in the bivariate analyses. However, the vancomycin trough value, modeled as a continuous variable, was the only vancomycin exposure variable associated with nephrotoxicity in the multivariate analyses.
The results indicate that a vancomycin exposure-toxicity response relationship exists. The vancomycin trough value is the pharmacodynamic index that best describes this association.
Vancomycin is a glycopeptide antibiotic that has been in clinical use for nearly 50 years as a penicillin alternative to treat penicillinaseproducing strains of Staphylococcus aureus. It is one of the most widely used antibiotics in the United States for the treatment of serious gram-positive infections involving methicillin-resistant S. aureus (MRSA). 1 Early use of vancomycin was associated with a number of adverse effects, including infusionrelated toxicities, nephrotoxicity, and possible ototoxicity. Upon further
A simple and reproducible microtiter plate assay for measuring superoxide dismutase (SOD) activity is described. Water-soluble tetrazolium, the sodium salt of 4-[3-(4iodophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1,3-be nzene disulfonate, was used as a detector of superoxide radical generated by xanthine oxidase and hypoxanthine, in the presence of a range of concentrations of superoxide dismutase. A major advantage of the assay is that one reaction mixture is prepared and aliquotted into wells, avoiding pipetting errors and variable xanthine oxidase activity between samples. Inclusion of standardized SOD solution in each run enables inter-assay comparability without requiring a constant superoxide generation rate under all occasions. The assay is applicable for chloroform-ethanol red cell extracts as well as tissue homogenates without high-speed centrifugation. Fifty percent inhibition of formazan formation was achieved at 2.4+/-0.1 ng of Cu, ZnSOD per well with the coefficient of variation 4.2%.
An increased production of superoxide has been shown to mediate glutamate-induced neuron death. We monitored intracellular superoxide production of hippocampal neurons during and after exposure to the glutamate receptor agonist NMDA (300 microm). During a 30 min NMDA exposure, intracellular superoxide production increased significantly and remained elevated for several hours after wash-out of NMDA. After a 5 min exposure, superoxide production remained elevated for 10 min, but then rapidly returned to baseline. Mitochondrial membrane potential also recovered after wash-out of NMDA. However, recovery of mitochondria was transient and followed by delayed mitochondrial depolarization, loss of cytochrome c, and a secondary rise in superoxide production 4-8 hr after NMDA exposure. Treatment with a superoxide dismutase mimetic before the secondary rise conferred the same protection against cell death as a treatment before the first. The secondary rise could be inhibited by the complex I inhibitor rotenone (in combination with oligomycin) and mimicked by the complex III inhibitor antimycin A. To investigate the relationship between cytochrome c release and superoxide production, human D283 medulloblastoma cells deficient in mitochondrial respiration (rho(-) cells) were exposed to the apoptosis-inducing agent staurosporine. Treatment with staurosporine induced mitochondrial release of cytochrome c, caspase activation, and cell death in control and rho(-) cells. However, a delayed increase in superoxide production was only observed in control cells. Our data suggest that the delayed superoxide production in excitotoxicity and apoptosis occurs secondary to a defect in mitochondrial electron transport and that mitochondrial cytochrome c release occurs upstream of this defect.
Mitochondrial OXPHOS defects are responsible for a large group of human diseases and have been associated with degenerative disorders and aging. The accurate in vivo and in organello biochemical assessment of the OXPHOS system is necessary for the diagnosis and investigation of such conditions. Here I describe a set of accurate polarographic and spectrophotometric assays that use relatively small amounts of biological material (cells or isolated mitochondria) and discuss the biochemical parameters appropriate for discriminating partial OXPHOS defects.
Inhibition of mitochondrial respiratory chain complex I by rotenone had been found to induce cell death in a variety of cells.
However, the mechanism is still elusive. Because reactive oxygen species (ROS) play an important role in apoptosis and inhibition
of mitochondrial respiratory chain complex I by rotenone was thought to be able to elevate mitochondrial ROS production, we
investigated the relationship between rotenone-induced apoptosis and mitochondrial reactive oxygen species. Rotenone was able
to induce mitochondrial complex I substrate-supported mitochondrial ROS production both in isolated mitochondria from HL-60
cells as well as in cultured cells. Rotenone-induced apoptosis was confirmed by DNA fragmentation, cytochrome c release, and caspase 3 activity. A quantitative correlation between rotenone-induced apoptosis and rotenone-induced mitochondrial
ROS production was identified. Rotenone-induced apoptosis was inhibited by treatment with antioxidants (glutathione, N-acetylcysteine, and vitamin C). The role of rotenone-induced mitochondrial ROS in apoptosis was also confirmed by the finding
that HT1080 cells overexpressing magnesium superoxide dismutase were more resistant to rotenone-induced apoptosis than control
cells. These results suggest that rotenone is able to induce apoptosis via enhancing the amount of mitochondrial reactive
oxygen species production.
At least two mechanisms of early cytosolic acidification during apoptotic signaling have been described, one that involves caspase 8 activation downstream of receptor ligation and another dependent on mitochondria-derived hydrogen peroxide during merocil-induced apoptosis. Here, we show that Bcl-2 inhibits both mechanisms of acidification. Moreover, Bcl-2 overexpression resulted in a slightly elevated constitutive level of superoxide anion and pH in CEM leukemia cells. Interestingly, decreasing intracellular superoxide concentration with an inhibitor of the beta-nicotinamide adenine dinucleotide phosphate oxidase or by transient transfection with a dominant-negative form of the guanosine triphosphate-binding protein Rac1 resulted in a significant increase in the sensitivity of CEM/Bcl-2 cells to CD95- or merocil-induced apoptosis. This increase in sensitivity was a direct result of a significant increase in caspase 8 activation and caspase 8-dependent acidification in the absence of caspase 9 activity or cytochrome c release. These findings suggest a mechanism of switching from mitochondria-dependent to mitochondria-independent death signaling in the same cell, provided the intracellular milieu is permissive for upstream caspase 8 activation, and could have implications for favorably tailoring tumor cells for drug treatment even when the mitochondrial pathway is compromised by Bcl-2.
NADH:ubiquinone oxidoreductase (complex I) is a major source of reactive oxygen species in mitochondria and a significant contributor to cellular oxidative stress. Here, we describe the kinetic and molecular mechanism of superoxide production by complex I isolated from bovine heart mitochondria and confirm that it produces predominantly superoxide, not hydrogen peroxide. Redox titrations and electron paramagnetic resonance spectroscopy exclude the iron-sulfur clusters and flavin radical as the source of superoxide, and, in the absence of a proton motive force, superoxide formation is not enhanced during turnover. Therefore, superoxide is formed by the transfer of one electron from fully reduced flavin to O2. The resulting flavin radical is unstable, so the remaining electron is probably redistributed to the iron-sulfur centers. The rate of superoxide production is determined by a bimolecular reaction between O2 and reduced flavin in an empty active site. The proportion of the flavin that is thus competent for reaction is set by a preequilibrium, determined by the dissociation constants of NADH and NAD+, and the reduction potentials of the flavin and NAD+. Consequently, the ratio and concentrations of NADH and NAD+ determine the rate of superoxide formation. This result clearly links our mechanism for the isolated enzyme to studies on intact mitochondria, in which superoxide production is enhanced when the NAD+ pool is reduced. Therefore, our mechanism forms a foundation for formulating causative connections between complex I defects and pathological effects.
Staphylococcus aureus is one of the most commonly isolated organisms in nosocomial infections. While the prevalence of methicillin-resistant S. aureus (MRSA) continues to increase worldwide, there is concern about an increase in vancomycin MICs among S. aureus strains. The prevalence of MRSA and vancomycin MIC trends in S. aureus from patients in a university hospital were analyzed. Clinical Laboratory Standards Institute (CLSI, formerly NCCLS) reference
broth microdilution MIC testing was performed on all clinically relevant S. aureus isolates from January 2000 through December 2004. A total of 6,003 S. aureus isolates were analyzed. No vancomycin-resistant S. aureus isolates were detected. One MRSA isolate had a vancomycin MIC of 8 μg/ml and was confirmed as vancomycin-intermediate S. aureus. Among the 6,002 remaining isolates, a shift in vancomycin MICs from ≤0.5 to 1.0 μg/ml was observed during the 5-year period.
The percentage of S. aureus isolates with a vancomycin MIC of 1 μg/ml in 2004 was significantly higher than the percentage of isolates in 2000 (70.4%
versus 19.9%; P < 0.01). This vancomycin MIC shift was more notable in methicillin-susceptible S. aureus. Our 5 years of routine testing of clinical isolates using the CLSI reference broth microdilution MIC method demonstrated
a tendency toward decreasing susceptibility to vancomycin in S. aureus.
Recent guidelines recommend vancomycin trough concentrations between 15 and 20 mg/liter. In response, some clinicians increased vancomycin dosing to >or=4 g/day. Scant data are available regarding toxicities associated with higher vancomycin doses. The purpose of this study was to examine vancomycin-associated nephrotoxicity at >or=4 g/day. To accomplish the study objective, a cohort study among a random selection of patients receiving vancomycin or linezolid between 2005 and 2006 was performed. Patients were included if they (i) were >or=18 years of age, (ii) were nonneutropenic, (iii) were on therapy for >48 h, (iv) had baseline serum creatinine levels of <2.0 mg/dl, (v) did not suffer from cystic fibrosis, and (vi) had no intravenous contrast dye within the previous 7 days. For drug exposure, three treatment strata were created: standard vancomycin dose (<4 g/day), high vancomycin dose (>or=4 g/day), and linezolid. Nephrotoxicity was defined as a serum creatinine increase of 0.5 mg/dl or 50%, whichever was greater, after therapy initiation. Stratified Kaplan-Meier analysis and Cox modeling were used to compare times to nephrotoxicity across groups. During the study, 246 patients on vancomycin (26 patients taking >or=4 g/day and 220 patients taking <4 g/day) and 45 patients on linezolid met the criteria. A significant difference in nephrotoxicity between patients receiving >or=4 g vancomycin/day, those receiving <4 g vancomycin/day, and those receiving linezolid was noted (34.6%, 10.9%, and 6.7%, respectively; P = 0.001), and Kaplan-Meier analysis identified significant differences in time to nephrotoxicity for the high-vancomycin-dose cohort compared to those for groups taking the standard dose and linezolid. In the Cox model, patients taking >or=4 g vancomycin/day, a total body weight of >or=101.4 kg, estimated creatinine clearance of </=86.6 ml/min, and intensive care unit residence were independently associated with time to nephrotoxicity. The data suggest that higher-dose vancomycin regimens are associated with a higher likelihood of vancomycin-related nephrotoxicity.
The aim of this study was to investigate the effect of reactive oxygen species (ROS), produced by the mitochondrial respiratory chain, on the activity of complex III and on the cardiolipin content in bovine-heart submitochondrial particles (SMP). ROS were produced by treatment of nicotinamide adenine dinucleotide (NADH) respiring SMP with rotenone. This treatment resulted in a production of superoxide anion, detected by the epinephrine method, which was blocked by superoxide dismutase (SOD). Exposure of SMP to mitochondrial-mediated ROS generation resulted in a marked loss of complex III activity and in a parallel loss of mitochondrial cardiolipin content. Both these effects were completely abolished by SOD+catalase. Exogenous added cardiolipin was able to almost completely prevent the ROS-mediated loss of complex III activity. No effect was obtained with other major phospholipid components of the mitochondrial membrane such as phosphatidylcholine and phosphatidylethanolamine, or with peroxidized cardiolipin. The results demonstrate that mitochondrial-mediated ROS generation affects the activity of complex III via peroxidation of cardiolipin, which is required for the functioning of this multisubunit enzyme complex. These results may prove useful in probing molecular mechanisms of ROS-induced peroxidative damage to mitochondria, which have been proposed to contribute to those physiopathological conditions characterized by an increase in the basal production of ROS such as aging, ischemia/reperfusion and chronic degenerative diseases.
Panaxydol, a polyacetylenic compound derived from Panax ginseng roots, has been shown to inhibit the growth of cancer cells. In this study, we demonstrated that panaxydol induced apoptosis preferentially in transformed cells with a minimal effect on non-transformed cells. Furthermore, panaxydol was shown to induce apoptosis through an increase in intracellular Ca(2+) concentration ([Ca(2+)](i)), activation of JNK and p38 MAPK, and generation of reactive oxygen species (ROS) initially by NADPH oxidase and then by mitochondria. Panaxydol-induced apoptosis was caspase-dependent and occurred through a mitochondrial pathway. ROS generation by NADPH oxidase was critical for panaxydol-induced apoptosis. Mitochondrial ROS production was also required, however, it appeared to be secondary to the ROS generation by NADPH oxidase. Activation of NADPH oxidase was demonstrated by the membrane translocation of regulatory p47(phox) and p67(phox) subunits and shown to be necessary for ROS generation by panaxydol treatment. Panaxydol triggered a rapid and sustained increase of [Ca(2+)](i), which resulted in activation of JNK and p38 MAPK. JNK and p38 MAPK play a key role in activation of NADPH oxidase, since inhibition of their expression or activity abrogated membrane translocation of p47(phox) and p67(phox) subunits and ROS generation. In summary, these data indicate that panaxydol induces apoptosis preferentially in cancer cells, and the signaling mechanisms involve a [Ca(2+)](i) increase, JNK and p38 MAPK activation, and ROS generation through NADPH oxidase and mitochondria.
conflicting evidence regarding the association of vancomycin serum concentrations with efficacy and toxicity has resulted in controversy regarding optimal target concentrations. Recent publications recommend attaining higher vancomycin trough concentrations of 15 to 20 mg/L for target infections, yet limited research is available assessing the correlation of vancomycin serum concentrations with toxicity. The aim of this study was to evaluate the association between vancomycin serum trough concentrations and nephrotoxicity.
a 2-phase retrospective analysis was completed. Phase 1 evaluated 2493 courses of vancomycin completed between January 2003 and December 2007. The analysis describes a 5-year trend in vancomycin prescribing practices and assesses the association of nephrotoxicity with baseline serum creatinine, vancomycin serum trough concentrations, and duration of vancomycin therapy. Phase 2 examined patients receiving vancomycin therapy during 2007 to evaluate specific risk factors for development of nephrotoxicity.
the proportion of vancomycin serum trough concentrations ≥ 15 mg/L and ≥ 20 mg/L increased significantly over time. Statistical analysis identified vancomycin serum trough concentrations ≥ 14 mg/L, duration of vancomycin therapy ≥ 7 days, and baseline serum creatinine levels ≥ 1.7 mg/dL as independent predictors of nephrotoxicity. Phase 2 analysis again implicated mean vancomycin serum trough concentration as a significant predictor of nephrotoxicity. Nephrotoxicity resolved in 81% (17/21) of cases evaluated.
a higher vancomycin serum trough concentration and prolonged vancomycin therapy are associated with an increased risk of nephrotoxicity. The decision to target increased vancomycin trough concentrations should be based on an assessment of the severity of the infection and must consider the nephrotoxicity risk associated with increased vancomycin levels.
The recent emergence of meticillin-resistant Staphylococcus aureus (MRSA) strains with reduced susceptibility to vancomycin has prompted clinicians to prescribe vancomycin therapy targeting high trough concentrations (15-20 mg/L). Relevant studies (n=12) analysing the occurrence of nephrotoxicity with high-dose therapy were reviewed. Most studies were retrospective and the temporal relationship between elevated trough levels and development of nephrotoxicity was unclear, precluding a definitive cause-effect analysis. Available data suggest an association between vancomycin trough level and risk of nephrotoxicity as a function of intensity and duration of therapy (>7 days), compounded by concomitant receipt of nephrotoxins, vasopressor therapy and underlying physiological impairment. In separate studies in which a high trough concentration was measured prior to the onset of nephrotoxicity, the frequency of occurrence was 21-28% in patients with concomitant risks compared with 7% in patients without risks. A similar comparison between risk and no-risk groups who attained a standard trough concentration (10-15 mg/L) indicates the rates of occurrence as 9-21% vs. 2%. Onset of nephrotoxicity ranged from 4 days to 8 days from the start of therapy. The degree of renal dysfunction was modest, with a reported decrease of 35-45% in creatinine clearance from baseline. Resolution occurred in >70% of patients by the time of discharge. Future studies should detail clearly the temporal relationship between drug exposure and onset of nephrotoxicity, confounding risk factors, extent of injury and time course of recovery, and should also determine the relative risk versus benefit of high-dose vancomycin versus alternative agents.
Diabetic mellitus, a chronic metabolic disorder, is one of the most important health problems in the world, especially in developing countries. Our earlier investigations reported the beneficial action of arjunolic acid (AA) against streptozotocin-mediated type 1 hyperglycemia. We have demonstrated that AA possesses protective roles against drug- and chemical- (environmental toxins) induced hepatotoxicity. Liver is the main organ of detoxification. The purpose of this study was to explore whether AA plays any protective role against hyperglycemic hepatic dysfunctions and, if so, what molecular pathways it utilizes for the mechanism of its protective action. In experimental rats, type 1 hyperglycemia was induced by streptozotocin. AA was administered orally at a dose of 20mg/kg body wt both before and after diabetic induction. An insulin-treated group was included in the study as a positive control for type 1 diabetes. Hyperglycemia caused a loss in body weight, reduction in serum insulin level, and increased formation of HbA(1C) as well as advanced glycation end products (AGEs). Elevated levels of serum ALT and ALP, increased production of ROS and RNS, increased lipid peroxidation, increased 8-OHdG/2-dG ratio, and decreased GSH content and cellular antioxidant defense established the hyperglycemic liver dysfunction. Activation of iNOS, IkappaBalpha/NF-kappaB, and MAPK pathways as well as signals from mitochondria were found to be involved in initiating apoptotic cell death. Hyperglycemia caused overexpression of PARP, reduction in intracellular NAD as well as ATP level, and increased DNA fragmentation in the liver tissue of the diabetic animals. Results of immunofluorescence (using anti-caspase-3 and anti-Apaf-1 antibodies), DAPI/PI staining, and DNA ladder formation and information obtained from FACS analysis confirmed the apoptotic cell death in diabetic liver tissue. Histological studies also support the experimental findings. AA treatment prevented or ameliorated the diabetic liver complications and apoptotic cell death. The effectiveness of AA in preventing the formation of ROS, RNS, HbA(1C), AGEs, and oxidative stress signaling cascades and protecting against PARP-mediated DNA fragmentation can speak about its potential uses for diabetic patients.
Hydroethidine (HE; or dihydroethidium) is the most popular fluorogenic probe used for detecting intracellular superoxide radical anion. The reaction between superoxide and HE generates a highly specific red fluorescent product, 2-hydroxyethidium (2-OH-E(+)). In biological systems, another red fluorescent product, ethidium, is also formed, usually at a much higher concentration than 2-OH-E(+). In this article, we review the methods to selectively detect the superoxide-specific product (2-OH-E(+)) and the factors affecting its levels in cellular and biological systems. The most important conclusion of this review is that it is nearly impossible to assess the intracellular levels of the superoxide-specific product, 2-OH-E(+), using confocal microscopy or other fluorescence-based microscopic assays and that it is essential to measure by HPLC the intracellular HE and other oxidation products of HE, in addition to 2-OH-E(+), to fully understand the origin of red fluorescence. The chemical reactivity of mitochondria-targeted hydroethidine (Mito-HE, MitoSOX red) with superoxide is similar to the reactivity of HE with superoxide, and therefore, all of the limitations attributed to the HE assay are applicable to Mito-HE (or MitoSOX) as well.
Vancomycin-associated nephrotoxicity was reported in 0% to 5% of patients in the 1980s. This has been confirmed by numerous clinical trials comparing novel anti-methicillin-resistant Staphylococcus aureus agents with vancomycin at the Food and Drug Administration-approved dosage of 1 g every 12 hours. Treatment failures of vancomycin in patients with methicillin-resistant S. aureus infections have been reported despite in vitro susceptibility. These failures have led to the use of vancomycin doses higher than those approved by the Food and Drug Administration. Higher doses are being administered to achieve goal vancomycin trough concentrations of 10 to 20 microg/mL recommended by several clinical practice guidelines endorsed by the Infectious Diseases Society of America. Recent studies suggest that increased rates of nephrotoxicity are associated with aggressive vancomycin dosing. These increased rates are confounded by concomitant nephrotoxins, renal insufficiency, or changing hemodynamics. These studies also have demonstrated that vancomycin's nephrotoxicity risk is minimal in patients without risk factors for nephrotoxicity. Clinicians unwilling to dose vancomycin in accordance with clinical practice guidelines should use an alternative agent because inadequate dosing increases the likelihood of selecting heteroresistant methicillin-resistant S. aureus isolates.
Vinorelbine (VNR), a vinca alkaloid anticancer drug, often causes vascular injury such as venous irritation, vascular pain, phlebitis, and necrotizing vasculitis. The purpose of this study was to identify the mechanisms that mediate the cell injury induced by VNR in porcine aorta endothelial cells (PAECs). PAECs were exposed to VNR for 10 min followed by further incubation in serum-free medium without VNR. The exposure to VNR (0.3-30 microM) decreased the cell viability concentration and time dependently. The incidence of apoptotic cells significantly increased at 12 h after transient exposure to VNR. At the same time, VNR increased the activity of caspases. Interestingly, VNR rapidly depleted intracellular glutathione (GSH) and increased intracellular reactive oxygen species (ROS) production. Moreover, VNR depolarized the mitochondrial membrane potential and decreased cellular ATP levels. These VNR-induced cell abnormalities were almost completely inhibited by GSH and N-acetylcysteine. On the other hand, L-buthionine-(S,R)-sulfoximine, a specific inhibitor of GSH synthesis, aggravated the VNR-induced loss of cell viability. These results clearly demonstrate that VNR induces oxidative stress by depleting intracellular GSH and increasing ROS production in PAECs, and oxidative stress plays an important role in the VNR-induced cell injury.
A protein determination method which involves the binding of Coomassie Brilliant Blue G-250 to protein is described. The binding of the dye to protein causes a shift in the absorption maximum of the dye from 465 to 595 nm, and it is the increase in absorption at 595 nm which is monitored. This assay is very reproducible and rapid with the dye binding process virtually complete in approximately 2 min with good color stability for 1 hr. There is little or no interference from cations such as sodium or potassium nor from carbohydrates such as sucrose. A small amount of color is developed in the presence of strongly alkaline buffering agents, but the assay may be run accurately by the use of proper buffer controls. The only components found to give excessive interfering color in the assay are relatively large amounts of detergents such as sodium dodecyl sulfate, Triton X-100, and commercial glassware detergents. Interference by small amounts of detergent may be eliminated by the use of proper controls.
Transcellular transport and the accumulation of [14C]tetraethylammonium, a typical organic cation, by LLC-PK1 cell monolayers grown on microporous membrane filters were studied. Tetraethylammonium was accumulated progressively in the monolayers from the basolateral side and was transported unidirectionally to the apical side. The transcellular transport of tetraethylammonium was saturable, temperature dependent, and sensitive to the pH of the apical side of the monolayers. The apparent Michaelis constant and maximum velocity values for the transport were 67 microM and 222 pmol.mg protein-1.min-1, respectively. Unlabeled tetraethylammonium, amiloride, procainamide, cimetidine, and choline inhibited the basolateral uptake and transcellular transport of [14C]tetraethylammonium. The development of tetraethylammonium transport activity was observed in the differentiating cells. A sulfhydryl reagent inhibited the tetraethylammonium transport at both the basolateral and apical membranes of the LLC-PK1 cells. These findings suggest that these monolayers possess unidirectional transport systems for organic cations, corresponding to the secretion in the renal proximal tubules.
The subcellular localization of tobramycin and vancomycin in the renal cortices of rats was determined with ultrathin sections by immunogold labeling. Four groups of four rats each were treated for 10 days with saline (NaCl, 0.9%), tobramycin at dosages of 20 mg/kg of body weight per 12 h intraperitoneally, vancomycin at dosages of 25 mg/kg/12 h subcutaneously, or the combination tobramycin-vancomycin. On day 11, the animals were killed, and cubes of renal cortex were fixed overnight in phosphate-buffered glutaraldehyde (0.5%), dehydrated in ethanol, and embedded in Araldite 502 resin. Ultrathin sections were made and incubated with sheep antitobramycin antibody followed by protein A-gold (15-nm diameter) complex or rabbit antivancomycin antibody followed by gold (30-nm diameter)-labeled goat anti-rabbit antibody. For the double labeling, incubations were made on opposite sides of the grid. Tobramycin was detected over the lysosomes of proximal tubular cells, but the labeling was concentrated into small areas in the matrix of the lysosomes. Vancomycin was seen over the lysosomes of proximal tubular cells and was distributed uniformly throughout the matrix of the lysosomes. In rats treated with tobramycin-vancomycin, both drugs were still detected in lysosomes of proximal tubular cells. It is concluded that tobramycin and vancomycin accumulate in lysosomes of proximal tubular cells throughout 10 days of treatment and that vancomycin has no effect on the subcellular distribution of tobramycin.
The effect of vancomycin, a putatively nephrotoxic amine glycopeptide antibiotic, on the transport of organic cations was examined in rabbit renal basolateral and brush border membrane vesicles. The studies were conducted using a rapid filtration technique and the prototypic organic cation tetraethylammonium. In basolateral membrane vesicles, vancomycin cis-inhibited the electrogenic transport of tetraethylammonium with an IC50 value of 260 microM. In contrast, gentamicin, an aminoglycoside, was without effect. Inhibition by mepiperphenidol, a classical organic cation transport inhibitor, was observed with an IC50 value of 24 microM. Countertransport, that is, trans-stimulation experiments, were initiated in order to determine whether or not vancomycin was capable of traversing the plasma membrane. Vancomycin caused trans-stimulation of tetraethylammonium uptake. The specificity of inhibition was assessed by determining the effect of vancomycin on the transport of p-aminohippurate, an organic anion. Vancomycin did not inhibit transport, whereas probenecid, a classical organic anion inhibitor, did. In the brush border membrane, vancomycin had no effect on the transport of tetraethylammonium. These data are consistent with mediated transport for vancomycin across the basolateral membrane, but not across the brush border membrane. This implies that the nephrotoxicity of vancomycin may be due to entry through the basolateral membrane and the absence of mediated egress at the brush border membrane.
The characteristics of gentamicin transport have been studied by using cultured kidney epithelial cell line LLC-PK1. The uptake of gentamicin by the LLC-PK1 cells appeared to be linear for 30 min and reached the equilibrium at day 1. Marked stimulation of gentamicin uptake was observed on the development of a confluent cell density, accompanied by the increases of marker enzyme activities and Na+-dependent D-glucose transport in the apical membranes. Gentamicin uptake was inhibited by metabolic inhibitors such as rotenone and 2,4-dinitrophenol, and was inhibited competitively in the presence of other aminoglycosides. Depending on the external calcium concentration, calcium ionophore A23187 stimulated gentamicin uptake, whereas ethylene glycol bis(beta-aminoethyl ether)N,N1-tetraacetic acid, a calcium chelator, inhibited gentamicin uptake. These results suggest that gentamicin uptake by the LLC-PK1 cells may be mediated via specialized transport system, and calcium ion movement may play an important role as a regulatory factor for this transport system.
A retrospective chart review of 98 patients treated with 100 courses of intravenous vancomycin was undertaken to better define
its toxicity. Most of the patients carried diagnoses of Staphylococcus aureus or Staphylococcus epidermidis infection. Auditory
toxicity was not seen, and fever and rash occurred in only 1 to 3% of the subjects. Phlebitis was noted in 13% of the cases
and required discontinuation of therapy in 2%. Therapy was complicated by neutropenia (polymorphonuclear leukocyte count,
less than or equal to 1,000 cells per cm3) in 2% of the patients but was rapidly reversible. Nephrotoxicity was uncommon (5%)
and reversible in subjects receiving vancomycin alone, even when the therapy was continued. However, 35% of the patients receiving
vancomycin with an aminoglycoside developed significant elevations in serum creatinine. Although this high incidence may have
been due to the patient population selected or to the aminoglycoside therapy alone, the possibility of additive toxicity between
vancomycin and the aminoglycosides should be considered.
Renewed interest in vancomycin over the past decade has led to an abundance of data concerning the pharmacokinetics of vancomycin, and its dosage selection and concentration-response relationships.
No definitive data exist that correlate vancomycin serum concentrations with clinical outcomes. However, inconsistencies in sampling times for peak serum concentrations and differences in infusion times make interpreting vancomycin serum concentrations difficult. Furthermore, the evidence implicating vancomycin as a cause of oto- or nephrotoxicity is circumstantial, and these adverse effects may occur only in high-risk populations.
Owing to the variability in its dose-serum concentration relationship and multicompartmental pharmacokinetics, several methodologies have been developed for instituting and adjusting vancomycin dosages. Nomograms rely on a fixed volume of distribution and the relationship between vancomycin clearance and creatinine clearance. Since both of these factors may be altered in certain populations, dosage methodologies (both traditional and Bayesian) that use population- or patient-specific pharmacokinetic data perform better than standard nomograms for initiating vancomycin therapy. Controversy still exists as to whether a 1- or a 2-compartment model is more appropriate for making dosage adjustments; however, steady-state rather than non-steady-state vancomycin serum concentrations should be used for dosage adjustments. Certain pathophysiological states such as age, bodyweight and renal function contribute to altered pharmacokinetics and may alter the design of the dosage regimen.
Since no definitive relationship exists between vancomycin serum concentrations and either clinical outcome or adverse effects, considerable controversy surrounds the utility of monitoring serum vancomycin concentrations. Therefore, routine vancomycin serum concentration monitoring may be warranted only in specific populations, such as patients receiving concurrent aminoglycoside therapy or those receiving higher than usual dosages of vancomycin, patients undergoing haemodialysis and patients with rapidly changing renal function.
The nephrotoxic effects of vancomycin hydrochloride (VCM) and the potential drug-drug interaction with cilastatin sodium (CS) were examined in rabbits. The aim of the study was to measure the possible dose-related suppressive effects or elimination by cilastatin of the adverse reactions generated by vancomycin in the kidneys of rabbits. To clarify the interactions of these two drugs, we examined the nephrotoxicity and pharmacokinetics of VCM in the rabbit when administered alone and when coadministered with CS. VCM administered alone (300 mg/kg of body weight as an intravenous bolus; n = 5) caused typical symptoms of nephrotoxicity, such as increases in serum creatinine and blood urea nitrogen (BUN) levels, as well as morphological changes in the kidneys. A lack of such signs of nephrotoxicity was observed in the groups administered VCM plus CS (i.e., CS at 150 mg/kg plus VCM at 300 mg/kg or CS at 300 mg/kg plus VCM at 300 mg/kg, intravenous bolus; n = 5/group). At a reduced combination ratio of VCM plus CS (4:1 ratio, VCM at 300 mg/kg plus CS at 75 mg/kg, intravenous bolus; n = 5) some symptoms of nephrotoxicity induced by VCM were present, but the degree of this effect was much reduced and was significantly different from preadministration values by only modest increases of the BUN and N-acetyl-beta-D-glucosaminidase levels (P < 0.05). Overall clearance of VCM was accelerated by coadministration of CS and was found to be dose dependent upon CS. No changes in renal function values from the preadministration values were observed for animals receiving CS alone (300 mg/kg, intravenous bolus; n = 3). These results suggest that CS has the ability to reduce or eliminate in a dose-dependent manner the nephrotoxic effects caused by VCM administration in rabbits.
To provide insights into the possibility of reducing the nephrotoxicity of vancomycin (VCM) by cilastatin, the effect of cilastatin on the renal handling of VCM, as well as on glomerular filtration rate (GFR) and plasma protein binding of VCM, were studied using rats. After a bolus intravenous (iv) dose of VCM (100 mg/kg), concomitant cilastatin administration (100 mg/kg, iv) resulted in a significant increase in the total VCM clearance and significant decrease in the kidney uptake clearance of VCM, defined as kidney VCM concentration vs AUC ratio. Moreover, after a 3-h continuous iv infusion of VCM (18 or 90 mg/h/kg), significant decrease in the kidney uptake clearance of VCM was observed with concomitant cilastatin iv infusion (300 mg/h/kg). On the other hand, GFR and VCM plasma protein binding did not show any significant change with cilastatin. From the observation that cilastatin decreased the kidney uptake clearance of VCM and enhanced its urinary excretion, it was suggested that cilastatin inhibited the reabsorption of VCM in the renal proximal tubular cells. Thus, it may be possible that cilastatin alleviates the nephrotoxicity of VCM due to reduced accumulation and accelerated renal excretion of VCM.
The effect of amyloid beta-protein (Abeta) on the cellular reducing activity has been a controversial issue. We determined the cellular reducing activity in cultured astrocytes using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and 2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl )-2H-tetrazolium (WST-8) reduction assays following Abeta treatment. MTT reduction was inhibited whereas WST-8 reduction was unaffected by the Abeta treatment. Furthermore, the early extracellular appearance of MTT formazan, a reduced product of MTT, was observed in association with the rapid disappearance of intracellular formazan granules. Notably, similar results were obtained in cultures treated with chloroquine, a perturbant of membrane trafficking. Our results suggest that MTT formazan exocytosis is enhanced in a similar manner by Abeta and chloroquine and that this biological activity of Abeta may underlie the pathogenesis of Alzheimer's disease.
Vancomycin hydrochloride (VCM), a glycopeptide antibiotic, has a broad spectrum against methicillin-resistant Staphylococcus aureus (MRSA). As it is known to induce renal dysfunction, the dose and the duration of its administration are limited. Moreover, the mechanism of VCM-induced renal dysfunction remains to be unclear. To evaluate the involvement of free radical on VCM-induced renal dysfunction, we carried out analysis with a hexamethylenediamine-conjugated superoxide dismutase (AH-SOD) which rapidly accumulates in renal proximal tubule cells and inhibits oxidative injury of the kidney. Male Wistar rats (weighing 200-210 g) were intraperitonealy administered with 200 mg/kg of VCM twice a day for 7 days. AH-SOD 5 mg/kg/day was subcutaneously injected 5 min before every VCM injection. VCM induced renal injury dose-dependently. Biochemical analyses revealed that plasma levels of blood urea nitrogen and creatinine significantly increased in the VCM-treated group by an AH-SOD-inhibitable mechanism. VCM simultaneously elicited an increase of 8-OHdG levels and chemiluminescence intensity of free radical generation in the kidney. Histological examination revealed that VCM also elicited a marked destruction of glomeruli and necrosis of proximal tubules. AH-SOD inhibited these phenomena in the kidney. These results suggested that oxidative stress might underlie the pathogenesis of VCM-induced nephrotoxicity and targeting SOD and/or related antioxidants to renal proximal tubules might permit the administration of higher doses of VCM sufficient for eradication of MRSA without causing renal injury.
We reported previously that radiocontrast medium induces caspase-dependent apoptosis and that cAMP analogs inhibit cell injury in cultured renal tubular cells. In the present study, cellular mechanisms underlying the protective effects of cAMP were determined. Ioversol, a radiocontrast medium, caused cell injury accompanied by decreases in Bcl-2, increases in Bax, and caspase activation in LLC-PK1 cells. Both cell injury and cellular events induced by ioversol were inhibited by dibutyryl cAMP and the prostacyclin analog beraprost. Dibutyryl cAMP increased phosphorylation of Akt and CREB, both of which were reversed by H89, wortmannin and the Akt inhibitor SH-6. The protective effect of dibutyryl cAMP was also reversed by these kinase inhibitors. In dominant-negative CREB-transfected cells, dibutyryl cAMP no longer prevented cell injury or inhibited changes in mRNA expression of Bcl-2 and Bax. In mice with unilateral renal occlusion, ioversol increased urinary excretion of N-acetyl-beta-d-glucosaminidase with concomitant decreases in Bcl-2 mRNA, increases in Bax mRNA, activation of caspase-3, and induction of apoptosis in tubular and interstitial cells. Beraprost completely reversed these in vivo effects of ioversol. These findings suggest that elevation of endogenous cAMP effectively prevents radiocontrast nephropathy through activation of A kinase/PI 3-kinase/Akt followed by CREB phosphorylation and enhanced expression of Bcl-2.
Vancomycin became available for clinical use >50 years ago but was soon discarded in favor of other antibiotics that were
deemed to be more efficacious and less toxic. The advent of pseudomembranous enterocolitis, coupled with the spread of methicillin-resistant
Staphylococcus aureus, led to a resurgence in the use of vancomycin. Almost immediately, concerns arose with regard to its therapeutic utility.
In addition, resistance to vancomycin developed, first in enterococci and later in staphylococci. Several types of resistance
have now been identified, each with a unique effect on infections treated with vancomycin. Recent studies have rekindled interest
in the best way to administer the antibiotic. The findings of future studies may result in a return to measuring levels of
vancomycin in serum, to assure a successful therapeutic outcome.
Although the definite etiology of Parkinson's disease is still unclear, increasing evidence has suggested an important role for environmental factors such as exposure to pesticides in increasing the risk of developing Parkinson's disease. In the present study, primary cultures prepared from embryonic mouse mesencephala were applied to investigate the toxic effects and underlying mechanisms of rotenone-induced neuronal cell death relevant to Parkinson's disease. Results revealed that rotenone destroyed dopaminergic neurons in a dose- and time-dependent manner. Consistent with the cytotoxic effect of rotenone as evidenced by dopaminergic cell loss, it significantly increased the release of lactate dehydrogenase into the culture medium, the number of necrotic cells in the culture and the number of nuclei showing apoptotic features. Rotenone exerted toxicity by decreasing the mitochondrial membrane potential, increasing reactive oxygen species production and shifting respiration to a more anaerobic state.
The objective of this study was to compare the beneficial effects of caffeic acid phenethyl ester (CAPE), vitamin C, vitamin E and N-acetylcysteine on vancomycin-induced nephrotoxicity. Thirty rats were randomly devided into six groups: (i) control; (ii) vancomycin, 200 mg/kg administrated via intraperitoneal route; (iii) vancomycin plus CAPE-vancomycin with 10 micromol/kg CAPE; (iv) vancomycin plus vitamin C-vancomycin (intraperitoneally) with 200 mg/dl vitamin C in drinking water; (v) vancomycin plus vitamin E-vancomycin with 1000 mg/kg body weight vitamin E (intramuscularly); and (vi) vancomycin plus N-acetylcysteine-vancomycin with 10 mg/kg body weight (intraperitoneally) of N-acetylcysteine. Vancomycin treatments were started 1 day after the first administrations of these agents and continued for 7 days. At the end of the experiments, catalase activity was significantly decreased by vancomycin in kidney homogenates (P < 0.05). Vitamin E, vitamin C, N-acetylcysteine and CAPE administrations decreased the blood urea nitrogen levels increased by vancomycin, although significant differences were detected only in the vitamins E and C groups (P < 0.05). Increased renal malondialdehyde and nitric oxide levels by vancomycin were significantly suppressed by agents used in the study (P < 0.05). Histopathological examination demonstrated prominent damages in the vancomycin-treated group. Vitamin E was the most beneficial agent on vancomycin-induced tubular damage, followed by vitamin C, N-acetylcysteine and CAPE treatments, respectively. The data suggest that vitamin E, as well as vitamin C, N-acetylcysteine and CAPE, could be useful for reducing the detrimental effects on vancomycin-induced toxicity in kidneys.
Experiments with isolated mitochondria have established that these organelles are pivotal intracellular sources of superoxide in a variety of pathophysiological conditions. Recently, a novel fluoroprobe MitoSOX Red was introduced for selective detection of superoxide in the mitochondria of live cells and was validated with confocal microscopy. Here we show approximately 3-7 fold dose- and time-dependent increase in mitochondrial superoxide production (measured by MitoSOX using flow cytometry and confocal microscopy) in rat cardiac derived H9c2 myocytes and/or in human coronary artery endothelial cells triggered by Antimycin A, Paraquat, Doxorubicin or high glucose. These results establish a novel, quantitative method for simple detection of mitochondrial superoxide generation simultaneously in a large population of live cells by flow cytometry. This method can also be adapted for immune cell studies with mixed population of T or B cells or their subsets to analyze mitochondrial superoxide levels using multiple labeled surface markers in individual populations.
The aim of the present study was to investigate the role of oxidative stress in renal injury and to determine whether erythropoietin (EPO) acts as an anti‐oxidant in vancomycin (VCM)‐induced renal impairment.
Twenty‐four rats were divided into three groups as follows: (i) control (Group 1); (ii) VCM treated (Group 2); and (iii) VCM + EPO treated (Group 3). Vancomycin (200 mg/kg, i.p.) was administered to Groups 2 and 3 for 7 days. Erythropoietin (150 IU/kg, i.p.) treatment was started 24 h before VCM and lasted for 7 days. On Day 8, renal tissues were excised and blood samples were collected. Serum creatinine and blood urea nitrogen were measured, along with renal malondialdehyde (MDA) levels, superoxide dismutase (SOD) and catalase (CAT) activity and tissue VCM levels. The kidneys were examined for any histopathological changes.
Renal MDA levels were found to be increased, whereas SOD and CAT activity was decreased, in the VCM‐treated group compared with the control group. There was a marked decrease in MDA levels and an increase in SOD activity, but not CAT activity, after VCM + EPO treatment. Marked histopathological alterations, including interstitial oedema, tubular dilatation, tubular epithelial cell desquamation and vacuolization, were observed in VCM‐treated rats. Histopathological changes were significantly improved after EPO administration.
In conclusion, the present data suggest that oxidative stress plays an important role in VCM‐induced nephrotoxicity. Erythropoietin seems to act as an anti‐oxidant, diminishing the toxic oxidative effects of VCM on renal tissues.
Rotenone, an inhibitor of NADH dehydrogenase complex, is a naturally occurring insecticide, which is capable of inducing apoptosis. Rotenone-induced apoptosis is considered to contribute to its anticancer effect and the etiology of Parkinson's disease (PD). We demonstrated that rotenone induced internucleosomal DNA fragmentation, DNA ladder formation, in human cultured cells, HL-60 (promyelocytic leukemia) and BJAB cells (B-cell lymphoma). Flow cytometry showed that rotenone induced H2O2 generation, followed by significant changes in the mitochondrial membrane potential (DeltaPsim). Caspase-3 activity increased in HL-60 cells in a time-dependent manner. These apoptotic events were delayed in HP100 cells, an H2O2-resistant clone of HL-60, confirming the involvement of H2O2 in apoptosis. Expression of anti-apoptotic protein, Bcl-2, in BJAB cells drastically inhibited DeltaPsim change and DNA ladder formation but not H2O2 generation, confirming the participation of mitochondrial dysfunction in apoptosis. NAD(P)H oxidase inhibitors prevented H2O2 generation and DNA ladder formation. These results suggest that rotenone induces O2(-)-derived H2O2 generation through inhibition of NADH dehydrogenase complex and/or activation of NAD(P)H oxidase, and H2O2 generation causes the disruption of mitochondrial membrane in rotenone-induced apoptosis.
Mechanisms of gentamicin transport in kidney epithelial cell line (LLC-PK1)
- Saito