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Role of reactive oxygen species in cocaine-induced cardiac dysfunction
Abstract
Contractility alterations and LV hypertrophy after chronic cocaine administration have been shown to be accompanied by an increase in oxidative stress. This study was carried out to investigate whether the production of reactive oxygen species is an early event of primary importance in cocaine-induced myocardial injury or simply occurs as a consequence of the ventricular dysfunction itself.
After 2 days of cocaine administration to rats, no differences were observed in echocardiographic parameters between the cocaine-treated group and the control group. However, an increase in oxidative stress in the myocardium was indicated by an increase in lipid peroxidation (+35%, cocaine vs. control), an increase in antioxidant enzymes (catalase +110%, glutathione peroxidase +40% and superoxide dismutase +38%) and of NADPH-driven superoxide production (assessed by chemiluminescence). Furthermore, higher gp91phox and p22phox mRNA expression, measured by quantitative real-time RT-PCR, was found in the cocaine group. On day 8, cocaine administration induced a cardiac dysfunction, characterized by a decrease in cardiac index (-30%, cocaine vs. controls) and left ventricular (LV) fractional shortening (-23%, cocaine vs. controls). This LV dysfunction was prevented by antioxidant treatment (100 mg/kg/day vitamin C and 100 U/kg/day vitamin E). Moreover, in these animals, antioxidant treatment decreased lipid peroxides and decreased the activity of NADPH oxidase, associated with the downregulation of gp91phox.
These data indicate that cocaine administration induces early NADPH-driven O2-. release which may play an important role in the development and progression of the LV dysfunction observed after chronic cocaine abuse.
... Notably, TBARS are an aspecific biomarker of peripheral oxidative stress, consisting of a quantification method for malondialdehyde (MDA) and stabile product of lipid peroxidation [118,119]. Accordingly with clinical data, experimental studies in rats showed an increase in MDA levels in the heart, both after COC selfadministration and extinction training [120] and after COC injection [121,122]. ...
... The results showed no differences in the activities of glutathione peroxidase and catalase between COC user and control subjects, whereas a significant reduction in the SOD activity was observed in erythrocytes. Accordingly, in a rat model of COC-induced heart injury, Moritz and coworkers [122] had shown that COC long-term administration caused a significant decrease in SOD activity; a biphasic trend in SOD concentration in rat spleen was observed after chronic COC administration in vivo [131] since that, after an early peak, SOD was significantly depleted 24 hours after COC treatment. ...
... Notably most of the glutathionylated proteins are intracellular [110]; to date, in human, the extent of glutathionylation in some pathologies (i.e., diabetes mellitus, hyperlipidemia, and uremia) can be measured only in blood [140], since in red blood cells Hb accounts for 97% of protein composition [141]. Importantly, increased levels of glutathionylated Hb were observed in [120][121][122]131] BDNF: malodialdehyde; TBARS: thiobarbituric acid reactive substances; BDNF: brain-derived neurotrophic factor; Hb: hemoglobin; RBC: red blood cells; SOD: superoxide dismutase. 8 Oxidative Medicine and Cellular Longevity cigarette smokers [142,143] suggesting that its quantification can be used as a low-invasive clinical biomarker of oxidative stress-associated diseases. ...
Cocaine abuse has long been known to cause morbidity and mortality due to its cardiovascular toxic effects. The pathogenesis of the cardiovascular toxicity of cocaine use has been largely reviewed, and the most recent data indicate a fundamental role of oxidative stress in cocaine-induced cardiovascular toxicity, indicating that mitochondrial dysfunction is involved in the mechanisms of oxidative stress. The comprehension of the mechanisms involving mitochondrial dysfunction could help in selecting the most appropriate mitochondria injury biological marker, such as superoxide dismutase-2 activity and glutathionylated hemoglobin. The potential use of modulators of oxidative stress (mitoubiquinone, the short-chain quinone idebenone, and allopurinol) in the treatment of cocaine cardiotoxic effects is also suggested to promote further investigations on these potential mitochondria-targeted antioxidant strategies.
... Recent observations support a key role of myocardial oxidative stress and mitochondrial dysfunction in the pathogenesis of cocaine-induced cardiomyopathy [65][66][67]. Indeed, substantial evidence of cardiac oxidative damage, including depletion of antioxidants and lipid peroxidation, has been obtained both in laboratory animals [65,66,68] and humans [69,70] exposed to cocaine. ...
... Recent observations support a key role of myocardial oxidative stress and mitochondrial dysfunction in the pathogenesis of cocaine-induced cardiomyopathy [65][66][67]. Indeed, substantial evidence of cardiac oxidative damage, including depletion of antioxidants and lipid peroxidation, has been obtained both in laboratory animals [65,66,68] and humans [69,70] exposed to cocaine. Underlying mechanisms include (1) indirect, catecholamine-induced, oxidative stress, due to formation of aminochromes and redox cycling compounds (see above), (2) the activation of the O 2 Á--generating enzymes NADPH oxidase [65,66,71,72] and xanthine oxidase [73], (3) the induced formation of ROS by dysfunctional mitochondria [67,73,74] and (4) the generation of pro-oxidant derivatives of cocaine metabolites [74,75]. ...
... Indeed, substantial evidence of cardiac oxidative damage, including depletion of antioxidants and lipid peroxidation, has been obtained both in laboratory animals [65,66,68] and humans [69,70] exposed to cocaine. Underlying mechanisms include (1) indirect, catecholamine-induced, oxidative stress, due to formation of aminochromes and redox cycling compounds (see above), (2) the activation of the O 2 Á--generating enzymes NADPH oxidase [65,66,71,72] and xanthine oxidase [73], (3) the induced formation of ROS by dysfunctional mitochondria [67,73,74] and (4) the generation of pro-oxidant derivatives of cocaine metabolites [74,75]. ...
Overactivation of the sympatho-adrenergic system is an essential mechanism providing short-term adaptation to the stressful conditions of critical illnesses. In the same way, the administration of exogenous catecholamines is mandatory to support the failing circulation in acutely ill patients. In contrast to these short-term benefits, prolonged adrenergic stress is detrimental to the cardiovascular system by initiating a series of adverse effects triggering significant cardiotoxicity, whose pathophysiological mechanisms are complex and only partially elucidated. In addition to the development of myocardial oxygen supply/demand imbalance induced by the sustained activation of adrenergic receptors, catecholamines can damage cardiomyocytes by fostering mitochondrial dysfunction, via two main mechanisms. The first one is calcium overload, consecutive to β-adrenergic receptor-mediated activation of protein kinase A and subsequent phosphorylation of multiple Ca(2+)-cycling proteins. The second one is oxidative stress, primarily related to the transformation of catecholamines into "aminochromes," which undergo redox cycling in mitochondria to generate copious amounts of oxygen-derived free radicals. In turn, calcium overload and oxidative stress promote mitochondrial permeability transition and cardiomyocyte cell death, both via the apoptotic and necrotic pathways. Comparable mechanisms of myocardial toxicity, including marked oxidative stress and mitochondrial dysfunction, have been reported with the use of cocaine, a common recreational drug with potent sympathomimetic activity. The aim of the current review is to present in detail the pathophysiological processes underlying the development of catecholamine and cocaine-induced cardiomyopathy, as such conditions may be frequently encountered in the clinical practice of cardiologists and ICU specialists.
... 147 In another study, after 2 days of cocaine administration to rats (total of 3 administrations of 7.5 mg/kg/day, i.p.) no differences were observed in echocardiographic parameters between the cocaine-treated and the control groups. 148 However, an increase in oxidative stress in the myocardium was demonstrated through increases in lipid peroxidation, a huge increase in antioxidant enzymes and in NADPH-driven O 2 ...
... In another protocol of the same study, cocaine hydrochloride (2 × 7.5 mg/kg/day, i.p.) was administered for 7 days; 24 h after the last administration, the evaluations were made. 148 Cocaine administration induced a cardiac dysfunction, characterized by a decrease in cardiac index and left ventricular fractional shortening. This left ventricular dysfunction was prevented by antioxidant treatment (100 mg/kg/day of vitamin C and 100 U/kg/day of vitamin E). ...
... •− release, which may play an important role in the development and progression of left ventricular dysfunction observed in chronic cocaine abuse. 148 Some of these data were confirmed in a mouse model of chronic escalating binge cocaine administration: days 1 to 4 at 3 × 15 mg/kg, days 5 to 8 at 3 × 20 mg/kg, days 9 to 12 at 3 × 25 mg/kg, and days 13 to 14 at 3 × 30 mg/kg. 149 Compared to controls, chronic binge cocaine administration significantly increased the cardiac NADPH-dependent O 2 ...
The heart is a target organ for oxidative stress-related injuries. Due to its very high energetic metabolic rate, the heart has the highest rate of production of reactive oxygen species, namely hydrogen peroxide (H2O2), per gram of tissue. Additionally, the heart has lower levels of antioxidants and of total activity of antioxidant enzymes when compared to other organs. Furthermore, drugs that have relevant antioxidant activity and that are used in the treatment of oxidative stress related cardiac diseases demonstrate better clinical cardiac outcomes than other drugs with similar receptor affinity but with no antioxidant activity. Several xenobiotics particularly target the heart and promote toxicity. Anticancer drugs, like anthracyclines, cyclophosphamide, mitoxantrone, and more recently tyrosine kinase targeting drugs are well known cardiac toxicants whose therapeutic application has been associated to a high prevalence of heart failure. High levels of catecholamines or drugs of abuse, namely amphetamines, cocaine, and even the consumption of alcohol for long periods of time are linked to cardiovascular abnormalities. Oxidative stress may be one common link for the cardiac toxicity elicited by these compounds. We aim to revise the mechanisms involved in cardiac lesions caused by the above mentioned substances specially focusing in oxidative stress related pathways. Oxidative stress biomarkers can be useful in the early recognition of cardiotoxicity in patients treated with these drugs and aid to minimize the setting of cardiac irreversible events.
... The mechanisms for cocaine-induced cardiotoxicity are multifactorial but many reports have suggested an important role for myocardial oxidative stress [7][8][9][10]. It has been well documented that cocaine induces catecholamine accumulation due to both the stimulation of the sympathetic system and the blockade of norepinephrine reuptake [11]. ...
... Cocaine hydrochloride (2 · 7.5 mg/kg/day, i.p.) was administered for 7 days. The cocaine dose used in this study was similar to those used in previous studies from our laboratory [9,10]. The animals in the control group and Se group were injected with saline. ...
... We observed that 7 days of cocaine administration induces a significant LV dysfunction characterized by a decrease in FS and cardiac index, and an increase in LV diameters. These observations are similar to those observed in previous animal studies after repeated cocaine administration [10,27] and in humans after long-term cocaine abuse [3]. In contrast, conventional parameter of LV contractility, dP/dt max , remains normal in this experimental model when evaluated 3 h after the last cocaine administration. ...
Chronic cocaine abuse causes cardiac dysfunction and induces oxidative stress. The goal of this study was to evaluate whether an enhanced antioxidant pool, induced by the administration of selenium, may prevent the myocardial dysfunction induced by cocaine. Cocaine was administered for 7 days (15 mg/kg/day, i.p.) to rats pretreated for 4 weeks with selenium (1.16 mg/L/day, p.o.). Cardiac function was evaluated by cardiac index and left ventricular (LV) fractional shortening (FS) measured by echocardiography. The redox ratio and enzymatic activities of glutathione peroxidase (GPX) and superoxide dismutase (SOD) were measured in the LV myocardium. Cocaine administration induced a cardiac dysfunction, as evidenced by a decrease in cardiac index and LV FS as well as by an increase in LV diameters. Moreover, antioxidant markers and redox ratio were altered in rats after cocaine exposure. Selenite supplementation induced a significant limitation of cardiac index and FS alterations observed after cocaine administration. This improvement in cardiac function was associated with a redox ratio recovery while SOD and GPX activities remained unchanged. Thus, selenite reversed both the oxidative stress and the contractile dysfunction induced by cocaine administration. These results suggest a major role of oxidative stress in the cocaine-induced cardiotoxicity.
... In recent years, an important area of study has addressed the sources and effect of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in heart diseases, both of which are considered major biologically relevant redox active molecules 14 . Accumulating evidence suggests that cocaine administration is associated with severe nitrosative/oxidative stress and mitochondrial dysfunction of the heart, and experimental studies have reported altered oxidative balance in the myocardium of chronic cocaine-treated animals [15][16][17][18][19][20][21][22][23] . ...
... Our results are in line with previous basic and clinical studies that have highlighted the central role of oxidative/nitrosative stress in cocaine toxicity [15][16][17][18][19][20][21][22][23] . ...
The aim of this study is to analyse cardiac specimens from human cocaine-related overdose, to verify the hypothesis that cardiac toxicity by acute exposure to high dosage of cocaine could be mediated by unbalanced myocardial oxidative stress, and to evaluate the apoptotic response. To address these issues, biochemical and immunohistological markers of oxidative/nitrosative stress were evaluated. We found that i-NOS, NOX2 and nitrotyrosine expression were significantly higher in the hearts of subjects who had died from high doses of cocaine, compared to the control group. Increase of these markers was associated with a dramatic increase in 8-OHdG, another marker of oxidative stress. A high number of TUNEL-positive apoptotic myocells was observed in the study group compared to the control group. The immunoexpression of TNF-α was significantly higher in the cocaine group compared to the control group. Furthermore, we detected a significantly stronger immunoresponse to anti-SMAC/DIABLO in our study group compared to control cases. Both cardiac Fas-dependent and mitochondria-dependent apoptotic pathways appeared to be activated to a greater extent in the cocaine group than in the control group. Our results highlight the central role of oxidative stress in cocaine toxicity. High levels of NOS can promote the oxidation process and lead to apoptosis.
... DOI: 10.3109/15376516.2015.1045658 Cocaine, cocaethylene & alveolar epithelial cells 611 generation (Moritz et al., 2003;Poon et al., 2007). Both COC and CE have been shown to induce NADPH-dependent enzymes (Fan et al., 2009;Moritz et al., 2003) which are responsible for the generation of ROS. ...
... Cocaine, cocaethylene & alveolar epithelial cells 611 generation (Moritz et al., 2003;Poon et al., 2007). Both COC and CE have been shown to induce NADPH-dependent enzymes (Fan et al., 2009;Moritz et al., 2003) which are responsible for the generation of ROS. Interestingly, these are the enzymes that also catalyze the reduction reactions of MTS and other tetrazolium compounds employed in cell viability assays. ...
Abuse of cocaine (COC) and alcohol have been among the leading causes of non-prescription drug-related deaths in the USA and are known to cause acute and chronic lung diseases. The co-abuse of COC and alcohol results in the production of an active metabolite, cocaethylene (CE). The effects of COC and its metabolites on the respiratory system have been scarcely studied. This study was aimed at comparing the toxic effects of eqimolar concentration (1 mM) of COC and CE on alveolar epithelial type II cells. This was performed by measuring cell growth, viability, clonogenic activity, cell cycle and reactive oxygen species (ROS) generation. The treatment of CE and COC resulted in a significant inhibition of cell proliferation with the formation of an average of three colonies which measured about 1.74 × 10(-15) m each and 25 colonies each of about 5.73 × 10(-15) m, respectively, while untreated cells yielded 31 colonies of 8.75 × 10(-15) m (p < 0.05). The treatments of CE and COC resulted in the reduction of the growth fraction of alveolar epithelial type II cells without significant decrease in viability. In addition, there was an approximately twofold increase in ROS generation as compared to the controls (p < 0.05). Therefore, CE-induced inhibition of cellular proliferation may contribute to the pathogenesis of diffuse alveolar damage in co-abusers of COC and alcohol.
... A similar suggestion arises for the potent lipid peroxidation due to active cocaine injections observed in the rat heart. Cocaine use is a risk factor for myocardial infarction, coronary artery spasm, arrhythmia and ischemia (Devi and Chan 1999;Vongpatanasin et al. 1999), and the mechanisms linked to drug toxicity come from disturbances in OS biomarkers (higher MDA levels and SOD activity, lower glutathione level, impairment of catalase, and glutathione peroxidase activity in the myocardium (Devi and Chan 1999;Moritz et al. 2003a). The latter effects were seen following passive cocaine injections in rats (Devi and Chan 1999;Moritz et al. 2003a); however, the cocaine doserange and the drug treatment time frame were much higher or longer, respectively, than in our study. ...
... Cocaine use is a risk factor for myocardial infarction, coronary artery spasm, arrhythmia and ischemia (Devi and Chan 1999;Vongpatanasin et al. 1999), and the mechanisms linked to drug toxicity come from disturbances in OS biomarkers (higher MDA levels and SOD activity, lower glutathione level, impairment of catalase, and glutathione peroxidase activity in the myocardium (Devi and Chan 1999;Moritz et al. 2003a). The latter effects were seen following passive cocaine injections in rats (Devi and Chan 1999;Moritz et al. 2003a); however, the cocaine doserange and the drug treatment time frame were much higher or longer, respectively, than in our study. ...
Oxidative stress (OS) generates or intensifies cocaine-evoked toxicity in the brain and peripheral organs. The aim of this study was to examine superoxide dismutase (SOD) activity and lipid peroxidation [measured by mal-ondialdehyde (MDA) levels] in rats during maintenance of cocaine self-administration and after withdrawal by a yoked-triad procedure. Our results indicate that repeated cocaine self-administration provoked an elevation of SOD activity in the hippocampus, frontal cortex, dorsal striatum, and liver. MDA levels were reduced in the brain, increased in the liver, kidney, and heart during maintenance of self-administration, and increased in the kidney in cocaine-yoked rats. In addition, following extinction training, we found enhanced MDA levels and SOD activity in the rat hippocampus, while changes in the activity of OS bio-markers in other brain structures and peripheral tissues were reminiscent of the changes seen during cocaine self-administration. These findings highlight the association between OS biomarkers in motivational processes related to voluntary cocaine intake in rats. OS participates in memory and learning impairments that could be involved in drug toxicity and addiction mechanisms. Therefore, further studies are necessary to address protective mechanisms against cocaine-induced brain and peripheral tissue damage.
... Total RNA was extracted from heart tissue by Tri-Reagent. A singlestrand cDNA as a PCR template was synthesized with oligo(dT) [12][13][14][15][16][17][18] primer and Moloney murine leukemia virus reverse transcriptase (Invitrogen, Carlsbad, CA). cDNA fragments of ICAM-1, VCAM-1, and E-and L-selectins were amplified with Taq DNA polymerase (Invitrogen). ...
... Oxidative stress may also play an important role in CAM expression following cocaine administration. Moritz et al. (17) reported an increase in oxidative stress in rat myocardium after 2 days of cocaine administration; stress was indicated by an increase in lipid peroxidation and antioxidant enzymes. In a transgenic rat model, characterized by hypertension and cardiac injury, stimulation of oxidative stress was followed by activation of the transcription factor NF-B, resulting in expression of adhesion molecules (ICAM-1 and VCAM-1), leukocyte infiltration in the vascular wall, and inflammation (15). ...
Cocaine treatment of mice with viral myocarditis significantly increases neutrophil infiltration into the myocardium and exacerbates the inflammatory response. The mechanisms of these effects are unknown; however, it may be that cocaine increases circulating catecholamines and consequently increases inflammatory cell adhesion to the coronary endothelium. Here, we examined the hypothesis that cocaine enhances inflammatory cell infiltration via catecholamine-induced upregulation of cell adhesion molecule (CAM) expression in adult BALB/c mouse hearts. Intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), endothelial leukocyte adhesion molecule-1 (E-selectin), and leukocyte adhesion molecule-1 (L-selectin) were detected by gene array analysis, RT-PCR, Western blotting, and immunohistochemical staining. CAMs were significantly upregulated in cocaine-treated mouse hearts. beta-Adrenergic stimulation with epinephrine also upregulated CAM expression, confirming the effects obtained with cocaine. Beta-adrenergic blockade with propranolol inhibited epinephrine-induced CAM expression. In hearts infused with polymorphonuclear neutrophils (PMN), an increased adhesion of PMN to the coronary endothelium was observed in cocaine-treated and epinephrine-treated mouse hearts compared with control hearts. Blocking antibodies against ICAM-1, E-selectin, and L-selectin significantly inhibited epinephrine-enhanced PMN adhesion, whereas anti-VCAM-1 had lesser effects. Our findings suggest that cocaine-induced neutrophil infiltration is mediated by beta-adrenergic stimulation through upregulation of CAM expression, which enhances PMN adhesion. Conversely, beta-adrenergic blockade with propranolol inhibits the effects of cocaine and epinephrine on CAM expression and decreases PMN adhesion to the coronary endothelium. These observations may be of significance for the development of preventative and therapeutic approaches to patients with cocaine- or catecholamine-induced myocarditis.
... In recent years, there have been increasing scientific reports of cocaine-induced cardiac dysfunction as a result of nitrosative/oxidative stress after cocaine use and mitochondrial dysfunction as a result of oxidative damage to cellular structures [17,18,117,118]. Cocaine directly inhibits the mitochondrial electron transport chain by increasing intramitochondrial Ca 2+ overload and depleting adenosine triphosphate (ATP) production. ...
... Collectively, the presented data identifies individuals with history of cocaine abuse and cardiac pathophysiology as being at an increased risk of death following cocaine use, even at doses routinely considered nontoxic. While it is not possible to attribute the morphological alterations of the cardiac architecture solely to cocaine use, or to distinguish them from underlying cardiac deficiencies, in the context of cardiac tissue remodelling the cases in this investigation are supportive of previously proposed links between cocaine use and long-term pathological cardiac injury (31)(32)(33)(34)(35)(36)(37)(38). It should be noted that many of the morphological and structural changes of the heart identified in this study are irreversible, therefore even after cessation of cocaine abuse, previously chronic or long-term users should still be considered a high-risk category for cardiac failure and myocardial ischaemia. ...
Background
The UK, as the ‘cocaine capital of Europe’, currently accounts for ~75% of all cocaine-related hospital admissions in Europe. This study aims to analyse trends in cocaine-related deaths in England, Wales, and Northern Ireland over 20 years (2000-2019).
Methods
Cases reported to the National Programme on Substance Abuse Deaths (NPSAD) occurring between 2000-2019 where cocaine was detected at post-mortem were extracted for analysis.
Results
5,339 cases were retrieved, with an increase in the rate of reporting over time. Cocaine was deemed a cause of death and quantified in post-mortem blood samples along with its major metabolite benzoylecgonine in 685 cases. Of these 685 cases, 25% (n=170/685) occurred following acute use, 22% (n=154/685) following chronic/binge use, 40% (n=271/685) in combination with morphine, 4% (n=29/685) in drug packer/swallower circumstances, and 9% (n=61/685) in a suicide context. Cardiac complications were evident in 22% of cases (n=154/685). The average concentration of cocaine detected in cardiac cases (900ng/ml) was considerably lower than that detected in cases where acute (19,100ng/ml) or chronic/binge (6,200ng/ml) dosing was evident.
Conclusions
This is the first cocaine-related mortality study in this geographical area. Deaths following cocaine use continue to rise despite its Class A drug listing in the UK. Whilst underlying and external risk factors including polydrug use, cardiac complications and mental health can all contribute to incidences of fatal drug toxicity following cocaine use, this study demonstrates that the risk of a cocaine overdose cannot be attributed to a specific blood concentration range.
... Sufficient evidence from in vivo animal models has shown a relationship between cardiovascular disorders and cocaine exposure via intraperitoneal administration [31,32]. Thus, Hematoxylin-eosin (H&E) and Elastica Masson-Goldner (EMG) staining were performed in order to assess the condition of the myocardium in our cocaine abuse model, applying tail vein administration ( Figure 1B-G). ...
Contraction band necrosis (CBN) is a common abnormality found in the myocardium of cocaine abusers, but is rarely reported in experimental models of cocaine abuse. Connexin 43 (Cx43) is essential for cardiac intercellular communication and the propagation of CBN. Under stress or injury, cardiac Cx43 is dephosphorylated, which is related to cardiomyocyte dysfunction and pathogenesis, whereas adiponectin exerts beneficial effects in the myocardium. In this study, we explore the effects of cocaine on cardiac Cx43 in vivo. Rats were administered cocaine via the tail vein at 20 mg/kg/day for 14 days, and showed widespread CBN, microfocal myocarditis and myocardial fibrosis, corresponding to a dysfunction of cardiac mitochondria under increased oxidative stress. The increase in dephosphorylated cardiac Cx43 and its negative correlation with the myocardial distribution of CBN after cocaine administration were determined. In addition, apoptosis and necroptosis, as well as increased adiponectin levels, were observed in the myocardium after cocaine exposure. Accordingly, we found altered profiles of cardiac Cx43, CBN and its negative correlation with dephosphorylated cardiac Cx43, and the possible involvement of adiponectin in the myocardium after 14 days of cocaine administration. The latter might play a protective role in the cardiotoxicity of cocaine. The current findings would be beneficial for establishing novel therapeutic strategies in cocaine-induced cardiac consequences.
... In recent years, there have been increasing scientific reports of cocaine-induced cardiac dysfunction as a result of nitrosative/oxidative stress after cocaine use and mitochondrial dysfunction as a result of oxidative damage to cellular structures [17,18,117,118]. Cocaine directly inhibits the mitochondrial electron transport chain by increasing intramitochondrial Ca 2+ overload and depleting adenosine triphosphate (ATP) production. ...
Psychomotor stimulants are the most commonly used prohibited substances after cannabis. Globally, their use reaches epidemiological proportions and is one of the most common causes of death in many countries. The use of illicit drugs has negative effects on the cardiovascular system and is one of the causes of serious cardiovascular pathologies, ranging from abnormal heart rhythms to heart attacks and sudden cardiac death. The reactive oxygen species generation, toxic metabolites formation, and oxidative stress play a significant role in cocaine-induced cardiotoxicity. The aim of the present review is to assess acute and chronic cocaine toxicity by focusing on the published literature regarding oxidative stress levels. Hypothetically, this study can serve as a basis for developing a rapid and effective method for determining oxidative stress levels by monitoring changes in the redox status of patients with cocaine intoxication.
... The main emphasis is given to experimentally tested alkaloids. Registered drugs, illicit drugs and those alkaloids that are a common part of human diet such as the well-described tropane (cocaine, interested readers can find information about cocaine and ROS in Ref. [2]) and purine alkaloids (caffeine, theophylline) were either intentionally omitted in this review or discussed only in the relevant cases (less known, unknown or novel mechanisms of action/toxicity). Due to the immense number of articles on the topic, the article concentrates 1) on the most common assay of in vitro scavenging activity, and 2) at the cell or in vivo level on the effect on NADPH-oxidase, the crucial player in reactive oxygen species (ROS) generation in cells. ...
Alkaloids have always attracted scientific interest due to either their positive or negative effects on human beings. This review aims to summarize their antioxidant effects by both classical in vitro scavenging assay and at the cellular level. Since most in vitro studies used the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging assay, the results from those studies are summed up in the first part of the article. In the second part, available data on the effect of alkaloids on NADPH-oxidase, the key enzyme for reactive oxygen species production, at the cellular level, are summarized. More than 130 alkaloids were tested by DPPH assay. However, due to methodological differences, a direct comparison is hardly possible. It can be at least concluded that some of them were either similar to or even more active than standard antioxidants and the number of aromatic hydroxyl groups seems to be the major determinant for the activity. The data on inhibition of NADPH-oxidase activity by alkaloids demonstrated that there is little relationship to the DPPH assay. The mechanism seems to be based on inhibition of synthesis, activation or translocation of NADPH-oxidase subunits. In some alkaloids, activation of the nuclear factor Nrf2 pathway was documented to be the grounds for inhibition of NADPH-oxidase. Interestingly, many alkaloids can behave both as anti-oxidants and pro-oxidants depending on conditions and pro-oxidation might be the reason for activation of Nrf2. Available data on other “antioxidant” transcription factors FOXOs and PPARs are also mentioned.
... It is reported that ROS takes part in the progress of cardiomyopathy after cocaine abuse (48,49). A significant reduction was observed in SOD in opium-treated Syrian hamsters as compared to the control group. ...
Context: This study was a systematic review that aimed to extract published articles regarding oxidant and antioxidants status in opium addiction by searching in PubMed, Google Scholar engine, SID, and Magiran databases. Evidence Acquisition: Sixty-six published articles were investigated in this review, which were selected from studies among the Iranian society and other societies from 1976 to 2015. All articles published in different fields of descriptive-analytical, experimental, and interventional studies were considered. Results: Several studies have shown that with increased production of free radicals and reactive oxygen species (ROS), the enzymatic and non-enzymatic antioxidants such as glutathione (GSH) and glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase activities, and also the concentration of vitamins A, E, C and total antioxidant capacity (TAC) decrease in opium addiction. Increased atherogenic indexes such as Low density lipoprotein/high density lipoprotein (LDL/HDL) ratio and malondialdehyde (MDA)maycontribute to the increased risk of cardiovascular disease. However, it has also increased other markers of oxidative stress including: isoprostanes, 8-oxoguanine and protein carbonyl. Conclusions: Oxidative stress increases in opium-addicted people. It seems that opium is capable of provoking oxidative stress and also, has harmful effects on lipid profile and antioxidant enzyme. Drug addicts were found to have antioxidant vitamin deficiency.
... Although it has been shown that the cocaine depresses mitochondrial respiration, decreased mitochondrial membrane potential and enhances mitochondrial production of ROS (Cunha-Oliveira et al. (2013)). In the body the toxicity of cocaine, due to its oxidative metabolism, is reported in liver with generation of ROS and lipid peroxidase (Oztezcan et al. (2000), Vitcheva (2012 ), in central nervous system (Sharan et al. (2003) ), in cardiovascular system with the release of superoxide (Moritz et al. (2003), Vergeade et al. (2012), in various form of renal disease where nitroxide and N-hydroxy derivative of norcocaine are believed to play a key role (Kovacic et al. (2002), Valente et al. (2012). Several studies reporting the deleterious effects of cocaine and its oxidized metabolites un numerous cutaneous manifestations (Cohen et al. (2010), Molgo et al. (2014), Menick & Salibian (2014)) and also skin ulcers (Shawwa et al. (2013)). ...
Cocaine abuse continues to be a major public health problem in the world. An upper numbers of individuals are initiating cocaine use with a stable rate of growth each year with an increasing number of people with cocaine related problems. Following cocaine oxidative pathways a ROS formation are generated. Oxidative stress has been demonstrated to play an important role in cocaine addiction and toxicity due to its oxidized metabolites produced by cytochrome P450 during cocaine biotransformation. The ROS induced genotoxicities include DNA damage, gene mutation, chromosome aberrations and micronuclei formation. 8-Hydroxy-2’-deoxyguanosine (8-OHdG) an oxidative modified DNA product, is the most representative product that may reflect oxidative damage induced by ROS. The present study was designed to investigate whether a systemic cocaine administration and its metabolism increase 8-OHdG production. Our findings clearly showed that cocaine promoted the ROS formation with significant increased of urinary 8-OHdG and MDA with a decreased of total scavenging capacity (TSC).
... Measurement of antioxidant enzyme activities. The activities of antioxidant enzymes, including GPx, CAT and SOD in the heart tissues of mice were assayed 67,68 . ...
Tumour necrosis factor receptor-associated factor 6 (TRAF6) is a ubiquitin E3 ligase that regulates important biological processes. However, the role of TRAF6 in cardiac hypertrophy remains unknown. Here, we show that TRAF6 levels are increased in human and murine hypertrophied hearts, which is regulated by reactive oxygen species (ROS) production. Cardiac-specific Traf6 overexpression exacerbates cardiac hypertrophy in response to pressure overload or angiotensin II (Ang II) challenge, whereas Traf6 deficiency causes an alleviated hypertrophic phenotype in mice. Mechanistically, we show that ROS, generated during hypertrophic progression, triggers TRAF6 auto-ubiquitination that facilitates recruitment of TAB2 and its binding to transforming growth factor beta-activated kinase 1 (TAK1), which, in turn, enables the direct TRAF6-TAK1 interaction and promotes TAK1 ubiquitination. The binding of TRAF6 to TAK1 and the induction of TAK1 ubiquitination and activation are indispensable for TRAF6-regulated cardiac remodelling. Taken together, we define TRAF6 as an essential molecular switch leading to cardiac hypertrophy in a TAK1-dependent manner.
... •− formation [56,58]. The role of NADPH-driven superoxide production in cocaine induced cardiac dysfunction is well recognized [59]. Indeed, the family of Nox enzymes is considered the major sources of ROS in the cardiovascular system [58,60]: the proteins of the Nox family produce O 2 •− by transferring an electron from NADPH (or NADH) to O 2 . ...
Oxidative stress (OS) is thought to play an important role in the pharmacological and toxic effects of various drugs of abuse. Herein we review the literature on the mechanisms responsible for the cardiovascular and hepatic toxicity of cocaine with special focus on OS-related mechanisms. We also review the preclinical and clinical literature concerning the putative therapeutic effects of OS modulators (such as N-acetylcysteine, superoxide dismutase mimetics, nitroxides and nitrones, NADPH oxidase inhibitors, xanthine oxidase inhibitors, and mitochondriotropic antioxidants) for the treatment of cocaine toxicity. We conclude that available OS modulators do not appear to have clinical efficacy.
... Crack cocaine has been reported to alter systemic biochemical markers, such as brain-derived neurotrophic factor (BDNF), IL-1β, IL-10, pro-inflammatory TNF-α and the thiobarbituric acid reactive substances (TBARS), a marker of oxidative stress that indicates the levels of lipid peroxidation [5,6]. Some studies showed that cocaine causes oxidative stress in different organs [7,8]. ...
Recent research suggests that crack cocaine use alters systemic biochemical markers, like oxidative damage and inflammation markers, but very few studies have assessed the potential effects of crack cocaine at the cellular level. We assessed genome instability by means of the comet assay and the cytokinesis-block micronucleus technique in crack cocaine users at the time of admission to a rehabilitation clinic and at two times after the beginning of withdrawal. Thirty one active users of crack cocaine and forty control subjects were evaluated. Comparison between controls and crack cocaine users at the first analysis showed significant differences in the rates of DNA damage (p = 0.037). The frequency of micronuclei (MN) (p < 0.001) and nuclear buds (NBUDs) (p < 0.001) was increased, but not the frequency of nucleoplasmic bridges (NPBs) (p = 0.089). DNA damage decreased only after the end of treatment (p < 0.001). Micronuclei frequency did not decrease after treatment, and nuclear buds increased substantially. The results of this study reveal the genotoxic and mutagenic effects of crack cocaine use in human lymphocytes and pave the way for further research on cellular responses and the possible consequences of DNA damage, such as induction of irreversible neurological disease and cancer.
... 35 In addition, there is evidence of direct cocaineinduced toxicity to the myocardium caused by increased oxidative stress. Interestingly, in laboratory conditions the induced myocardial dysfunction may be prevented by the use of antioxidants (vitamin C). 36 over a prolonged period, the insults of increased myocardial wall tension and increased oxidative stress will damage the myocardium in a similar manner to chronic hypertension, leading to the development of significant LVh and its well recognised deleterious effects. 37 Cocaine-induced cardiomyopathy has received little attention in the published literature to date. ...
Physicians involved in acute medical take or emergency department work will be well aware of the various acute presentations associated with cocaine and amphetamine use. As the population ages and the heavy users from previous decades accumulate ‘crack years’, the longer term consequences of these drugs on the cardiovascular system are becoming more evident. This article will review the pharmacology of stimulant drugs and discuss acute and chronic problems associated with their use. Management strategies of acute presentations, including the role of vasodilators in cocaine-induced myocardial infarction, the avoidance of beta-blockers in acute toxicity and the potential role of alpha-2 agonists are discussed. The management of chronic cardiac damage associated with cocaine or amphetamine abuse has an insufficient evidence base to suggest anything other than complete abstinence in combination with well established therapies.
... Furthermore, in vivo cocaine exposure also decreased GSH content in hepatic mitochondria [63], increased the activity of Mn-SOD, the mitochondrial isoform of SOD, and decreased the activities of GPx and catalase [64]. Treatment with antioxidants could prevent cocaineinduced cardiac dysfunction [65,66], suggesting that ROS play a central role in the development and progression of cardiomyopathy after cocaine abuse [67]. ...
Drug addiction is a public health and social burden. Presently, the most abused illicit substance is cannabis, followed by amphetamines, cocaine and opioids, with different prevalence in different countries. Several evidences support a role for oxidative stress in the toxicity induced by many drugs of abuse in different organs, such as the brain, heart, liver or kidneys. This leads to oxidation of important cellular macromolecules, and may culminate in cell dysfunction and death. In this review we describe the evidences for oxidative damage and depletion of antioxidants upon exposure to drugs of abuse, especially amphetamines, cocaine and opiates. We also discuss the sources of oxidative stress induced by drugs of abuse, including oxidative metabolism of drugs, oxidative metabolism of monoamines by monoamine oxidases or by auto-oxidation, mitochondrial dysfunction, excitotoxicity, microglial activation, inflammation, hyperthermia and the effects of drug interactions. These consolidate oxidative stress as a relevant mechanism contributing for the cytotoxicity of drugs of abuse and for behavioral changes associated with drug addiction.
... Recent studies have also demonstrated that cocaine induces oxidative stress in organs such as liver, heart and brain [1,34,36]. The extant evidence suggests that the administration of cocaine increases levels of dopamine and its metabolites, resulting in an exacerbated production of reactive oxygen species (ROS) [16,44]. ...
BACKGROUND: A growing body of evidence suggests that crack cocaine misuse has widespread systemic and cognitive consequences, but little attention has been given to its systemic pathophysiology. We report here changes in inflammation markers, oxidative damage and brain derived neurotrophic factor in a sample of outpatients with crack cocaine use disorders. METHODS: Fifty-three outpatients were recruited for this cross-sectional study and matched with fifty control subjects. The focus of this report is in between group differences in cytokines, oxidative damage and brain-derived neurotrophic factor (BDNF). RESULTS: Crack cocaine use was associated with higher BDNF levels when compared to controls, present only in those who used crack cocaine in the last month. Patients also had higher circulating levels of IL-1β, TNF-α and IL-10 when compared to controls. There were no significant differences in oxidative damage between patients and controls. CONCLUSIONS: These results represent a first demonstration that crack cocaine use disorders entail an activation of the reward, immune and inflammatory systems.
... 45 Indeed, it has been proposed that cocaine induces erythrocytosis and increases the production of reactive oxygen species in the cardiovascular system. 46,47 Unlike cocaine, chronic single administration of testosterone enhanced hypotensive response to SNP. Previous studies have reported an increase or a decrease, and no changes, in the vascular action of nitrovasodilators after chronic administration of testosterone. ...
Abuse of cocaine and androgenic-anabolic steroids has become a serious public health problem. Despite reports of an increase in the incidence of simultaneous illicit use of these substances, potential toxic interactions between cocaine and androgenic-anabolic steroids in the cardiovascular system are unknown. In the present study, we investigated the effect of single or combined administration of testosterone and cocaine for 1 or 10 consecutive days on basal cardiovascular parameters, baroreflex activity, and hemodynamic responses to vasoactive agents in unanesthetized rats. Ten-day combined administration of testosterone and cocaine increased baseline arterial pressure. Changes in arterial pressure were associated with altered baroreflex activity and impairment of both hypotensive response to intravenous sodium nitroprusside and pressor effect of intravenous phenylephrine. Chronic single administration of either testosterone or cocaine did not affect baseline arterial pressure. However, testosterone-treated animals presented rest bradycardia, cardiac hypertrophy, alterations in baroreflex activity, and enhanced response to sodium nitroprusside. Repeated administration of cocaine affected baroreflex activity and impaired vascular responsiveness to both sodium nitroprusside and phenylephrine. One-day single or combined administration of the drugs did not affect any parameter investigated. In conclusion, the present results suggest a potential interaction between toxic effects of cocaine and testosterone on the cardiovascular activity. Changes in baseline arterial pressure after combined administration of these 2 drugs may result from alterations in baroreflex activity and impairment of vascular responsiveness to vasoactive agents.
... However, clinical therapies with adrenoceptor antagonists are problematic and not always effective (Vasica and Tennant, 2002; Afonso et al., 2007). It has been discovered recently that cocaine administration is associated with severe oxidative stress in the heart (Moritz et al., 2003; Pacifici et al., 2003; Kovacic, 2005; Ren et al., 2006; Isabelle et al., 2007). Although there are several potential enzymatic sources of ROS existing in the heart, in an animal model of chronic cocaine administration, treatment with apocynin (an NADPH oxidase inhibitor) has been reported to be effective in reducing ROS generation and to restore the cardiac output, stroke volume, and fractional shortening, suggestive of the involvement of an NADPH oxidase (Isabelle et al., 2007). ...
Chronic cocaine exposure is associated with severe cardiac complications, but the mechanisms of cocaine cardiotoxicity remain unclear, and current therapies are unsatisfactory. We investigated the hypothesis of oxidative stress-mediated cardiotoxicity and the role of NADPH oxidase in this process in a mouse model of chronic escalating "binge" cocaine administration (milligrams per kilogram): days 1 to 4 at 3 x 15 mg, days 5 to 8 at 3 x 20 mg, days 9 to 12 at 3 x 25 mg, and days 13 to 14 at 3 x 30 mg. Compared with vehicle controls, chronic binge cocaine administration significantly increased the cardiac NADPH-dependent O(2)(.) production (1.96- +/- 0.4-fold) as detected by tiron (an O(2)(.) scavenger)-inhibitable lucigenin chemiluminescence and dihydroethidium fluorescence. Cocaine-induced reactive oxygen species (ROS) production was associated with significant increases ( approximately 2-fold) in the protein expressions of Nox2 (an isoform of NADPH oxidase) and its regulatory subunits: p22(phox), p67(phox), p47(phox), p40(phox), and Rac1, and in p47(phox) phosphorylation as detected by immunoblotting (all p < 0.03). Increased Nox2 activity was accompanied by the activation of extracellular signal-regulated kinase 1/2, p38 mitogen-activated protein kinase (MAPK), and c-Jun NH(2)-terminal kinase, notably in the cardiomyocytes. Cell culture experiments revealed that cocaine-induced ROS production was primarily a direct action of cocaine on cardiac myocytes, which caused severe oxidative damage to myocytes and cell death as detected by terminal deoxynucleotidyl transferase dUTP nick-end labeling assay. These could be inhibited by inhibitors to protein kinase C (bisindolymaleimide) or by depletion of Nox2 using small interfering RNA. In conclusion, chronic cocaine administration directly causes severe myocardial oxidative stress through the activation of Nox2 oxidase. Increased ROS production contributes to MAPK activation and the subsequent myocyte damage. Inhibitors to NADPH oxidase or antioxidants may have therapeutic potential in the treatment of cocaine cardiotoxicity.
... Although these studies suggest a likelihood role of the mitochondria/cytochrome c pathway in cocaine-induced apoptosis in myocardial cells, it remains unknown whether cocaine-induced cytochrome c release trails or precedes the activation of caspases and apoptosis. It has been shown that cocaine induces oxidative stress in the heart and liver ( Chan, 1996, 1999; Moritz et al., 2003a ,b). Stress-responsive mitogen-activated protein kinases (MAPKs; c-Jun N-terminal kinase and p38 MAPKs) have been implicated in cell death/apoptosis in the myocardium (Sugden and Clerk, 1998). ...
Cocaine induces apoptosis in fetal rat myocardial cells (FRMCs). However, the mechanisms are not clear. The present study examined the role of p38 mitogen-activated protein kinase (MAPK) and cytochrome c release in the cocaine-induced apoptosis in primary culture of FRMCs prepared from the fetal heart of gestational age of 21 days. Cocaine induced time-dependent, concurrent increases in cytochrome c release and activities of caspase-9 and caspase-3, which preceded apoptosis. Caspase-8 was not activated. In accordance, cyclosporin A and the inhibitors of caspase-9 and caspase-3 inhibited cocaine-induced caspase activation and apoptosis. Cocaine stimulated a transient increase in the p38 MAPK activity at a time point of 15 min but reduced the extracellular signal-regulated kinase (ERK) activity at 5 and 15 min in FRMCs. The p38alpha MAPK inhibitor SB203580 [4-(4-fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)1H-imidazole] inhibited cocaine-induced activation of caspases and apoptosis. In contrast, the p38beta MAPK and mitogen-activated protein kinase kinase/ERK inhibitors SB 202190 [4-(4-fluorophenyl)-2-(4-hydroxyphenyl)-5-(4-pyridyl)-1H-imidazole] and PD98059 (2'-amino-3'-methoxyflavone), respectively, increased apoptosis in the absence of cocaine and potentiated cocaine-induced apoptosis. Consistent with its inhibition of apoptosis, SB203580 inhibited cocaine-induced cytochrome c release and activation of caspase-9 and caspase-3. In addition, cocaine induced a decrease in Bcl-2 protein levels, with no effect on Bax levels. The cocaine-mediated reduction of Bcl-2 levels was not affected with SB203580 and the caspase inhibitors. The results suggest that in FRMCs, p38alpha MAPK plays an important role in the cocaine-induced apoptosis by promoting cytochrome c release, downstream or independent of Bcl-2 protein-mediated regulation. In contrast, p38beta MAPK and ERK protect fetal myocardial cells against apoptosis.
Abuse of the potent psychostimulant cocaine is widely established to have cardiovascular consequences. The cardiotoxicity of cocaine is mainly associated with oxidative stress and mitochondrial dysfunction. Mitochondrial dynamics and biogenesis, as well as the mitochondrial unfolded protein response (UPR mt ), guarantee cardiac mitochondrial homeostasis. Collectively, these mechanisms act to protect against stress, injury, and the detrimental effects of chemicals on mitochondria. In this study, we examined the effects of cocaine on cardiac mitochondrial dynamics, biogenesis, and UPR mt in vivo. Rats administered cocaine via the tail vein at a dose of 20 mg/kg/day for 7 days showed no structural changes in the myocardium, but electron microscopy revealed a significant increase in the number of cardiac mitochondria. Correspondingly, the expressions of the mitochondrial fission gene and mitochondrial biogenesis were increased after cocaine administration. Significant increase in the expression and nuclear translocation of activating transcription factor 5, the major active regulator of UPR mt , were observed after cocaine administration. Accordingly, our findings show that before any structural changes are observable in the myocardium, cocaine alters mitochondrial dynamics, elevates mitochondrial biogenesis, and induces the activation of UPR mt . These alterations might reflect cardiac mitochondrial compensation to protect against the cardiotoxicity of cocaine.
La sélénoprotéine T (SelT) est une protéine thiorédoxine-like abondamment exprimée au cours du développement embryonnaire chez le rat, mais son expression tend à disparaître après la naissance, notamment dans le coeur, suggérant un rôle limité de la SelT à l’âge adulte. Néanmoins, nous avons pu montrer que la SelT est réexprimée au niveau cardiaque suite à une ligature de l’artère coronaire (LC), suggérant le rôle potentiellement protecteur de cette protéine au cours des pathologies cardiovasculaires. Le but de notre projet fut donc d’évaluer les effets cardiaques d’une thérapie par la SelT au cours de l’insuffisance cardiaque, moyennant soit une thérapie protéique, soit une thérapie génique visant à surexprimer la SelT au niveau cardiaque ou au niveau systémique. La supplémentation en SelT (15μg/kg/jour, minipompes ip) a permis d’améliorer significativement le débit cardiaque et la fraction de raccourcissement du VG, mais également d’améliorer les pressions télé-systoliques et télé-diastoliques du ventricule gauche ainsi que la perfusion coronaire. Ces changements sont associés à une diminution du stress oxydant cardiaque ainsi qu’à une répression des mécanismes inflammatoires cardiaques. L’ensemble de ces améliorations a été observé sans modification de la taille d’infarctus. En parallèle, nous avons pu montrer qu’une injection intraveineuse d’un rAAV9-SelT (1.1011vg) une semaine après la LC permettait de diminuer significativement la dilatation ventriculaire gauche 3 mois après la LC. De manière concomitante, la thérapie génique par la SelT améliore le débit cardiaque ainsi que la perfusion cardiaque. Ces changements sont associés à une amélioration de la compliance et de l’élastance cardiaque. Par ailleurs, l’injection intramusculaire d’un rAAV8-SelT suivant le même protocole que précédemment. Nous avons pu montrer que le traitement par cet AAV permettait de diminuer significativement la dilatation du VG et d’améliorer la fraction de raccourcissement. De plus, la thérapie génique a permis d’améliorer la perfusion cardiaque ainsi que la relaxation coronaire endothélium-dépendante. Nous avons également pu montrer que l’ensemble des effets de la SelT sont médiés par le résidu Sec, dès lors que la modification de ce résidu par une alanine, annihile totalement l’ensemble des effets positifs observés au cours de notre étude. Ainsi, nos résultats ont permis de montrer clairement que le rôle bénéfique d’un traitement par la SelT au cours de l’ICC, et ce, grâce à un mécanisme sélénocystéine-dépendant. La SelT semble donc être une cible thérapeutique prometteuse pour le traitement de cette pathologie.
Studies have now conclusively linked impaired sperm function with reactive oxygen species attack on sperm-a process more commonly referred to as "oxidative stress". While research studies suggest that up to 80% of infertile men have evidence of oxidative stress, the majority of fertility specialists do not test their patients for oxidative stress, nor offer empirical antioxidant treatment. This is primarily due to a lack of availability of oxidative stress testing in the majority of clinical andrology laboratories, and a general ignorance of the importance of oxidative stress as a cause of male infertility amongst treating physicians. The first aim of this chapter is to outline the causes of oxidative stress so that they may be identified by simple history and examination. Sentinel signs of oxidative stress seen on routine semen analysis are then reviewed, together with a discussion of the benefits and pitfalls of direct testing for sperm oxidative stress. Finally, the management of sperm oxidative stress is outlined, including improvements in lifestyle, better management of underlying chronic illness, antioxidant medical therapy and surgical approaches to oxidative stress. © Springer Science+Business Media, LLC 2012. All rights reserved.
Cocaine is one of the principal drugs of abuse, it is an illegal psychostimulant, and the chronic consumption of cocaine causes damage in a range of body organs. Cocaine is known to undergo metabolism through multiple enzymatic pathways leading to the formation of several highly reactive species, which have been proposed to exert a direct toxic effect in the organs. All its metabolites may be involved in the activation of redox cycles, the depletion or decrease of antioxidant enzymes and the consequent generation of reactive oxygen species (ROS) leading to oxidative stress (OS) events, the lipid peroxidation and disruption of cellular activity, and consequently cocaine-induced organs damage. However, the exact mechanisms of cocaine-mediated toxicity in all the organs are not fully understood. This review provides extensive evidence in support of the hypothesis that oxidative metabolites play important roles comprising oxidative stress, defined as a disturbance of redox signaling and control that can cause malfunction in organs such as the brain, heart, liver, kidney and skin.
Oxidative stress is an imbalance between free radicals and antioxidants, and is an important etiological factor in the development of hypertension. Recent experimental evidence suggests that subpressor doses of angiotensin II elevates oxidative stress and blood pressure. We aimed to investigate the oxidative stress related mechanism by which a subpressor dose of angiotensin II induces hypertension in a normotensive rat model. Normotensive male Wistar rats were infused with a subpressor dose of angiotensin II for 28 days. The control group was sham operated and infused with saline only. Plasma angiotensin II and H(2)O(2) levels, whole-blood glutathione peroxidase, and AT-1a, Cu/Zn SOD, and p22phox mRNA expression in the aorta was assessed. Systolic and diastolic blood pressures were elevated in the experimental group. There was no change in angiotensin II levels, but a significant increase in AT-1a mRNA expression was found in the experimental group. mRNA expression of p22phox was increased significantly and Cu/Zn SOD decreased significantly in the experimental group. There was no significant change to the H(2)O(2)and GPx levels. Angiotensin II manipulates the free radical-antioxidant balance in the vasculature by selectively increasing O(2)(-) production and decreasing SOD activity and causes an oxidative stress induced elevation in blood pressure in the Wistar rat.
Cocaine is a powerful stimulant that gives users a temporary sense of euphoria, mental alertness, talkativeness, and a decreased need for food and sleep. Cocaine intoxication is the most frequent cause of drug-related death reported by medical examiners in the US, and these events are most often related to the cardiovascular manifestations of the drug. Once playing a vital role in medicine as a local anesthetic, decades of research have established that cocaine has the ability to cause irreversible structural damage to the heart, greatly accelerate cardiovascular disease, and initiate sudden cardiac death. Although pathologic findings are often reported in the literature, few images are available to support these findings, and reviews of cocaine cardiopathology are rare. We describe the major pathologic findings linked to cocaine abuse in earlier research, their underlying mechanisms, and the treatment approaches currently being used in this patient population.
A MEDLINE search was conducted to identify all English language articles from January 2000 to June 2008 with the subject headings and key words ‘cocaine’, ‘heart’, ‘toxicity’, and ‘cardiotoxicity’. Epidemiologic, laboratory, and clinical studies on the pathology, pathophysiology, and pharmacology of the effects of cocaine on the heart were reviewed, along with relevant treatment options. Reference lists were used to identify earlier studies on these topics, and related articles from Google Scholar were also included.
There is an established connection between cocaine use and myocardial infarction (MI), arrhythmia, heart failure, and sudden cardiac death. Numerous mechanisms have been postulated to explain how cocaine contributes to these conditions. Among these, cocaine may lead to MI by causing coronary artery vasoconstriction and accelerated atherosclerosis, and by initiating thrombus formation. Cocaine has also been shown to block K+ channels, increase L-type Ca2+ channel current, and inhibit Na+ influx during depolarization, all possible causes for arrhythmia. Additionally, cocaine use has been associated with left ventricular hypertrophy, myocarditis, and dilated cardiomyopathy, which can lead to heart failure if drug use is continued.
Certain diagnostic tools, including ECG and serial cardiac markers, are not as accurate in identifying MI in cocaine users experiencing chest pain. As a result, clinicians should be suspicious of cocaine use in their differential diagnosis of chest pain, especially in the younger male population, and proceed more cautiously when use is suspected.
Treatment for cocaine-related cardiovascular disease is in many ways similar to treatment for traditional cardiovascular disease. However use of β-receptor antagonists and class Ia and III anti-arrhythmics is strongly discouraged if the patient is likely to continue cocaine use, because of documented adverse effects.
The medical community is in urgent need of a pharmacologic adjunct to cocaine-dependence treatment that can deter relapse and reduce the risks associated with cardiovascular disease in these patients.
The purpose of this study was to investigate whether or not gender differences may be present in the expression of a number of urinary proteins which may serve as markers of inflammation and oxidative stress. Males and females have different patterns of illness and different life spans, suggesting basic biological traits exert significant control on the incidence of rhabdomyolysis, renal failure, atherosclerosis, myocardial ischemia, myocardial contraction band formation, autoimmune disorders and general inflammatory diseases. Men are at greater risk for cardiovascular disease; however women, particularly elderly women, have higher fatality rates due to heart failure. Renal diseases progress far more quickly in men, possibly due to testosterone. Men also have higher kidney bulk related to androgen expression. Gender disparity may be most obvious in autoimmune disorders; of the estimated 8.5 million people diagnosed with autoimmune disorders, approximately 80% are women. Hashimoto’s thyroiditis, the most common form of hypothyroidism, is up to 10 times more common in women. Systemic Lupus Erythematosus (SLE), an autoimmune disease characterized by acute and chronic inflammation, is 9 times more common in women. Rheumatoid arthritis (RA), an autoimmune disease affecting approximately 1.3 million people in the United States, is four times more common in women. Diabetes mellitus (DM), affecting more than 17 million people – the majority of which are women, is linked to microvascular and macrovascular diseases such as kidney failure, strokes and atherosclerosis. These conditions are linked to physiological changes that may alter the expression of certain biomarkers of inflammation and oxidative stress.
Over the past several decades, it has become increasingly clear that the role of diet, smoking, and other lifestyle choices clearly influence the etiology and pathophysiology of these diseases. The use of drugs, both licit and illicit, has been clearly linked to many of these diseases. Illicit substances, particularly cocaine, have been demonstrated to produce pathophysiological changes to many systems in the body which can greatly influence the progression of existing and drug-induced disease states leading to systemic damage. A relationship between the expression of markers of inflammation, oxidative stress, cardiac damage, or other systemic injury, gender and cocaine use has not been clearly established.
Urine is an important medium for assessment of general health status. It has classically been used to monitor disease states; glucosuria as an indicator of diabetes and renal dysfunction, microorganisms signifying urinary tract or bladder infection, and biomarkers such as human chorionic gonadotropin to confirm pregnancy. Recently urine has been used to assess biomarker expression and disease states. Urine is an ideal clinical tool for toxicological screens; it is readily accessible, non invasive and typically supplied in sufficient quantity to accommodate multiple tests. In this study, urine specimens were collected and analyzed for creatinine, cocaine, total protein, aldosterone, c-reactive protein (hsCRP), myeloperoxidase (MPO), microalbumin (MAB), neutrophil gelatinase-associated lipocalin (NGAL), heat shock protein 90α (hsp90α), vascular endothelial growth factor (VEGF), myoglobin, pro atrial natriuretic peptide (proANP) and interleukins 1α, 1 β , and 6 using ELISA and colorimetric assays.
Urine specimens that tested negative for all illicit substances in the standard National Institute on Drug Abuse (NIDA) 10 panel showed differences in a number of these biomarkers which strongly suggested significant differences between males and females for aldosterone, IL1α and IL1β. In addition, significance is suggested for MPO and CRP. Although sex specific differences in serum expression have been noted for some of the markers in both animal and human models, this has not been previously demonstrated in human urine. This may have implications for what is typically referred to as ‘normal’ values. Gender specific differences were not apparent in urine specimens that tested positive for cocaine. Also, in males only, the levels of myoglobin and aldosterone significantly increased.
Background and objectiveInflammation and oxidative stress take part in the development of the pathogenesis of acute coronary syndromes (ACS). The aim of this study was to analyze serum concentrations of high sensitivity C-reactive protein (PCR-as) and malondialdehyde (MDA) in cocaine consumer patients and ACS.
Cocaine is a powerful stimulant of the sympathetic nervous system by inhibiting catecholamine reuptake, stimulating central sympathetic outflow, and increasing the sensitivity of adrenergic nerve endings to norepinephrine (NE). It is known, from numerous studies, that cocaine causes
irreversible structural changes on the brain, heart, lung and other organs such as liver and kidney and there are many mechanisms involved in the genesis of these damages. Some effects are determined by the overstimulation of the adrenergic system. Most of the direct toxic effects are mediated
by oxidative stress and by mitochondrial dysfunction produced during the metabolism of noradrenaline or during the metabolism of norcocaina, as in cocaine-induced hepathotoxicity. Cocaine is responsible for the coronary arteries vasoconstriction, atherosclerotic phenomena and thrombus formation.
In this way, cocaine favors the myocardial infarction. While the arrhythmogenic effect of cocaine is mediated by the action on potassium channel (blocking), calcium channels (enhances the function) and inhibiting the flow of sodium during depolarization. Moreover chronic cocaine use is associated
with myocarditis, ventricular hypertrophy, dilated cardiomyopathy and heart failure. A variety of respiratory problems temporally associated with crack inhalation have been reported. Cocaine may cause changes in the respiratory tract as a result of its pharmacologic effects exerted either
locally or systemically, its method of administration (smoking, sniffing, injecting), or its alteration of central nervous system neuroregulation of pulmonary function. Renal failure resulting from cocaine abuse has been also well documented. A lot of studies demonstrated a high incidence
of congenital cardiovascular and brain malformations in offspring born to mothers with a history of cocaine abuse.
Recent studies have shown that long-term cocaine use induces diastolic impairment and a myocardial oxidative stress. Recently, we have reported that cocaine-induced cardiac dysfunction may be due to a mitochondrial reactive oxygen species (ROS) overproduction which occurs at the same time as xanthine oxidase (XO) activation. In this work, we hypothesized that XO activation contributes to mitochondrial ROS overproduction, which in turn contributes to diastolic dysfunction. To test this, we used a well-established in vivo model of cocaine-induced diastolic dysfunction. In this experimental model treated with or without allopurinol, an inhibitor of XO, we measured mitochondrial ROS production and function. Mitochondrial alterations were characterized by an increase in oxygen consumption through complexes I and III, a reduction in ATP production, and an increased ROS production specifically in isolated interfibrillar mitochondria. Allopurinol treatment prevented the rise in mitochondrial ROS levels and the decrease in ATP production. In the same way, allopurinol treatment improved ventricular relaxation with a decrease in Tau, an index of LV relaxation and of end-diastolic pressure volume relation. These results confirmed the critical role of xanthine oxidase in the sequence of events leading to cocaine-induced cardiac dysfunction.
Medicinal agents, beside occupational and environmental agents, remain one of the most common causes for interstitial lung diseases (ILD). A major problem with ILD is the recognition of the causative agent. In some cases more or less characteristic features of presentation are described. Often, the connection between drug-use and the development of related inflammatory damage or idiosyncratic toxicities is hard to recognize and objectify. Cocaine, a xenobiotic and the most commonly used illicit drug, causes serious medical and social problems. An increasing incidence of lung toxicity related to cocaine or crack-use is being reported worldwide. However, the mechanism of the resulting lung injury is not fully understood. This review summarizes possible molecular mechanisms explaining intra-individual variability in cocaine response and lung toxicity. The importance of including pharmacogenomics in the work-up of patients with suspected drug-induced lung toxicity is highlighted.
Cocaine-induced cardiovascular disorders such as hypertension, thrombosis, myocardial dysfunction, cardiac dysrhythmias and endocarditis have received widespread attention in the context of cocaine abuse. The number of sudden deaths from cardiac causes, including myocardial infarction, ventricular tachyarrhythmia or aortic dissection, is also increasing. This manuscript will highlight the recent employment of study about cocaine cardiotoxicity and oxidative stress. Evidence has revealed that cardiac oxidative stress is a prominent early event of cocaine administration, which severely compromises the cardiac antioxidant cellular system and causes cardiac antioxidant cellular system injuries. Oxidative damage such as peroxidation of membrane phospholipids and depletion of nonenzymatic antioxidants such as glutathione have been found in the myocardium of chronic cocaine-treated animals and in patients. The data indicate that cocaine administration compromised the heart's antioxidant defense system. About the mechanisms involved in the cellular damage, the evidence that cocaine causes apoptosis in the heart comes from in vivo study. In animals model after short-term and long term-cocaine administration, the investigators demonstrates the role of Reactive Oxygen Species as a trigger of cardiac injury induced by cocaine. Cocaine also increased infiltration of inflammatory cells in the heart, and apoptotic cells were predominantly found near inflammatory cells. The role of oxidative stress in cocaine-induced apoptosis in the heart is wide studied and documented.
Cocaine is a widely abused drug responsible for the majority of deaths ascribed to drug overdose. Many mechanisms have been proposed in order to explain the various cocaine associated cardiovascular complications. Conventionally, cocaine cardiotoxicity has been thought to be mediated indirectly through its sympathomimetic effect, i.e., by inhibiting the reuptake and thus increasing the levels of neuronal catecholamines at work on adrenoceptors. Increased oxidative stress, reactive oxygen species, and cocaine-induced apoptosis in the heart muscle have suggested a new way to understand the cardiotoxic effects of cocaine. More recent studies have led the attention to the interaction of cocaine and some metabolites with cardiac sodium, calcium and potassium channels. The current paper is aimed to investigate the molecular mechanisms of cocaine cardiotoxicity which have a specific clinical and forensic interest. From a clinical point of view the full knowledge of the exact mechanisms by which cocaine exerts cardio - vascular damage is essential to identify potential therapeutic targets and improve novel strategies for cocaine related cardiovascular diseases. From a forensic point of view, it is to be underlined that cocaine use is often associated to sudden death in young, otherwise healthy individuals. While such events are widely reported, the relationship between cardiac morphological alterations and molecular/cellular mechanisms is still controversial. In conclusion, the study of cocaine cardiovascular toxicity needs a strict collaboration between clinicians and pathologists which may be very effective in further dissecting the mechanisms underlying cocaine cardiotoxicity and understanding the cardiac cocaine connection.
Oxidative stress (OS) generates or intensifies cocaine-evoked toxicity in the brain and peripheral organs. The aim of this study was to examine superoxide dismutase (SOD) activity and lipid peroxidation [measured by malondialdehyde (MDA) levels] in rats during maintenance of cocaine self-administration and after withdrawal by a yoked-triad procedure. Our results indicate that repeated cocaine self-administration provoked an elevation of SOD activity in the hippocampus, frontal cortex, dorsal striatum, and liver. MDA levels were reduced in the brain, increased in the liver, kidney, and heart during maintenance of self-administration, and increased in the kidney in cocaine-yoked rats. In addition, following extinction training, we found enhanced MDA levels and SOD activity in the rat hippocampus, while changes in the activity of OS biomarkers in other brain structures and peripheral tissues were reminiscent of the changes seen during cocaine self-administration. These findings highlight the association between OS biomarkers in motivational processes related to voluntary cocaine intake in rats. OS participates in memory and learning impairments that could be involved in drug toxicity and addiction mechanisms. Therefore, further studies are necessary to address protective mechanisms against cocaine-induced brain and peripheral tissue damage.
Chronic cocaine abusers experience brain and peripheral vascular dysfunction, the severity of which tends to be greater in men than women. The mechanisms underlying these effects of cocaine are unknown. Because nitric oxide (NO) abnormalities play key roles in development of vascular dysfunction in several disorders, we determined whether vascular nitric oxide end product (NOx) levels, which can serve as markers of systemic vascular NO production, are reduced in cocaine-dependent (CD) subjects. Plasma samples from 24 CD men, 12 CD women, and matched comparison subjects (19 men, 14 women) were analyzed with a Sievers 280i nitric oxide chemiluminescence detection analysis system. NOx levels in comparison in women and men were 24.9 ± 6.6 and 23.3 ± 5.7 μmol/L, and in CD women and men were 22.5 ± 8.4 and 13.0 ± 9.6 μmol/L, respectively. ANCOVA analysis, adjusted for lifetime smoking, indicated group (P < 0.0005) and sex (P = 0.04) effects, both of which survived posthoc Scheffe tests. Reduced NOx levels in CD men drove the group difference. These data suggest that chronic cocaine abuse is associated with reduced NOx levels in men, although the finding also may be attributable to factors indirectly related to cocaine abuse, including cohort differences in other drug use or lifestyle factors. These findings warrant additional studies to more directly characterize vascular NO turnover in cocaine abusers and to establish whether NO abnormalities contribute to cocaine-associated vascular dysfunction and to sex differences in cocaine's effects.
Thirty-six million Americans older than 12 years of age have used cocaine in their lifetime. Cocaine abuse is on the rise and it brings the challenges to treat the complication associated with it, particularly cardiovascular complications. As the understanding of pathophysiology of cocaine-associated cardiovascular complications is advancing, the treatment modalities are also modifying. In this article, common cardiovascular complications associated with acute or chronic cocaine use and their treatment are reviewed.
The goal of this study was to assess mitochondrial function and ROS production in an experimental model of cocaine-induced cardiac dysfunction. We hypothesized that cocaine abuse may lead to altered mitochondrial function that in turn may cause left ventricular dysfunction. Seven days of cocaine administration to rats led to an increased oxygen consumption detected in cardiac fibers, specifically through complex I and complex III. ROS levels were increased, specifically in interfibrillar mitochondria. In parallel there was a decrease in ATP synthesis, whereas no difference was observed in subsarcolemmal mitochondria. This uncoupling effect on oxidative phosphorylation was not detectable after short-term exposure to cocaine, suggesting that these mitochondrial abnormalities were a late rather than a primary event in the pathological response to cocaine. MitoQ, a mitochondrial-targeted antioxidant, was shown to completely prevent these mitochondrial abnormalities as well as cardiac dysfunction characterized here by a diastolic dysfunction studied with a conductance catheter to obtain pressure-volume data. Taken together, these results extend previous studies and demonstrate that cocaine-induced cardiac dysfunction may be due to a mitochondrial defect.
Cocaine abuse is a significant problem among pregnant women. The present study tested the hypothesis that prenatal cocaine exposure impairs myogenic reactivity of coronary arteries in adult offspring. Pregnant rats received cocaine (30 mg kg(-1) day(-1)) or saline from days 15 to 21 of gestational age, and experiments were conducted in 3-month-old offspring. In pressurized coronary septal arteries, the diameter and vessel wall intracellular Ca2+ concentrations were measured simultaneously in the same tissue as a function of intraluminal pressure. Cocaine did not affect KCl-induced contractions of coronary arteries in either males or females but decreased the distensibility in male vessels. In male offspring, cocaine treatment resulted in a significant decrease in pressure-dependent myogenic contractions. Inhibition of eNOS with NG-nitro-L-arginine did not alter the myogenic response in either saline control or cocaine-treated animals. In females, cocaine caused a significant increase in pressure-dependent myogenic contractions. NG-nitro-L-arginine did not affect the myogenic response in the control animals but blocked the cocaine-mediated effect. In both males and females, the pressure-induced increases in vessel wall Ca2+ concentrations were not significantly different between cocaine and saline groups. The ratio of changes in the diameter to Ca2+ concentrations in the pressurized arteries was significantly less in male but greater in female offspring after cocaine treatment. The results suggest that prenatal cocaine exposure causes reprogramming of coronary myogenic tone via changes in the Ca2+ sensitivity in a sex-dependent manner, leading to an increased risk of dysfunction of coronary autoregulation in adult offspring.
Cocaine is a powerful stimulant that gives users a temporary sense of euphoria, mental alertness, talkativeness, and a decreased need for food and sleep. Cocaine intoxication is the most frequent cause of drug-related death reported by medical examiners in the US, and these events are most often related to the cardiovascular manifestations of the drug. Once playing a vital role in medicine as a local anesthetic, decades of research have established that cocaine has the ability to cause irreversible structural damage to the heart, greatly accelerate cardiovascular disease, and initiate sudden cardiac death. Although pathologic findings are often reported in the literature, few images are available to support these findings, and reviews of cocaine cardiopathology are rare. We describe the major pathologic findings linked to cocaine abuse in earlier research, their underlying mechanisms, and the treatment approaches currently being used in this patient population. A MEDLINE search was conducted to identify all English language articles from January 2000 to June 2008 with the subject headings and key words 'cocaine', 'heart', 'toxicity', and 'cardiotoxicity'. Epidemiologic, laboratory, and clinical studies on the pathology, pathophysiology, and pharmacology of the effects of cocaine on the heart were reviewed, along with relevant treatment options. Reference lists were used to identify earlier studies on these topics, and related articles from Google Scholar were also included. There is an established connection between cocaine use and myocardial infarction (MI), arrhythmia, heart failure, and sudden cardiac death. Numerous mechanisms have been postulated to explain how cocaine contributes to these conditions. Among these, cocaine may lead to MI by causing coronary artery vasoconstriction and accelerated atherosclerosis, and by initiating thrombus formation. Cocaine has also been shown to block K+ channels, increase L-type Ca2+ channel current, and inhibit Na+ influx during depolarization, all possible causes for arrhythmia. Additionally, cocaine use has been associated with left ventricular hypertrophy, myocarditis, and dilated cardiomyopathy, which can lead to heart failure if drug use is continued. Certain diagnostic tools, including ECG and serial cardiac markers, are not as accurate in identifying MI in cocaine users experiencing chest pain. As a result, clinicians should be suspicious of cocaine use in their differential diagnosis of chest pain, especially in the younger male population, and proceed more cautiously when use is suspected. Treatment for cocaine-related cardiovascular disease is in many ways similar to treatment for traditional cardiovascular disease. However use of beta-receptor antagonists and class Ia and III anti-arrhythmics is strongly discouraged if the patient is likely to continue cocaine use, because of documented adverse effects. The medical community is in urgent need of a pharmacologic adjunct to cocaine-dependence treatment that can deter relapse and reduce the risks associated with cardiovascular disease in these patients.
See article by Moritz et al. \[9\] (pages 834–843) in this issue.
Cocaine (benzoylmethylecgonine) is increasingly used as an illegal stimulatory and hallucinogenic drug. This abuse is associated with a large array of clinically relevant cardiovascular side effects that after long-term use may lead from myocardial hypertrophy and necrosis to progressive left ventricular dysfunction [1]. To further dissect the underlying mechanisms, two pathophysiological entities have to be taken into account and deserve further attention: the acute effects and the biochemical and cellular changes in the myocardium after chronic abuse.
Cocaine was introduced as the first local anaesthetic agent at the end of the 19th century. Its local anaesthetic effect originates in from a blockade of voltage-gated Na+ channels. This is accompanied by a sympathomimetic influence of the drug due to central stimulation of sympathetic outflow and inhibition of norepinephrine reuptake into sympathetic nerve terminals. The sympathomimetic property supports the local anaesthetic influence by inducing local vasoconstriction and thus preventing fast dilution of the drug.
In the cardiovascular system, acute cocaine application prolongs QRS duration, increases heart rate and myocardial contractility, and elicits intense vasoconstriction in coronary and peripheral vascular beds [1]. Inhibition of cardiac Na+ current by cocaine is voltage- and frequency-dependent. Reduced Na+ current leads to a depression of V max in the action potential (AP) that reduces AP propagation in the heart, consistent with the finding of a prolonged QRS complex. The reduction …
c.grohe{at}uni-bonn.de
Cocaine is one of the principal drugs of abuse. Although impressive advances have been made, unanswered questions remain concerning mechanism of toxicity and addiction. Discussion of action mode usually centers on receptor binding and enzyme inhibition, with limited attention to events at the molecular level. This review provides extensive evidence in support of the hypothesis that oxidative metabolites play important roles comprising oxidative stress (OS), reactive oxygen species (ROS), and electron transfer (ET). The metabolites include norcocaine and norcocaine derivatives: nitroxide radical, N-hydroxy, nitrosonium, plus cocaine iminium and formaldehyde. Observed formation of ROS is rationalized by redox cycling involving several possible ET agents. Three potential ones are present in the form of oxidative metabolites, namely, nitroxide, nitrosonium, and iminium. Most attention has been devoted to the nitroxide-hydroxylamine couple which has been designated by various investigators as the principal source of ROS. The proximate ester substituent is deemed important for intramolecular stabilization of reactive intermediates. Reduction potential of nitroxide is in accord with plausibility of ET in the biological milieu. Toxicity by cocaine, with evidence for participation of OS, is demonstrated for many body components, including liver, central nervous system, cardiovascular system, reproductive system, kidney, mitochondria, urine, and immune system. Other adverse effects associated with ROS comprise teratogenesis and apoptosis. Examples of ROS generated are lipid peroxides and hydroxyl radical. Often observed were depletion of antioxidant defenses, and protection by added antioxidants, such as, thiol, salicylate, and deferoxamine. Considerable evidence supports the contention that oxidative ET metabolites of cocaine are responsible for much of the observed OS. Quite significantly, the pro-oxidant, toxic effects, including generation of superoxide and lipid peroxyl radicals, plus depletion of glutathione, elicited by nitroxide or the hydroxylamine derivative, were greater than for the parent drug. The formaldehyde metabolite also appears to play a role. Mechanistic similarity to the action of neurotoxin 3,3'-iminodipropionitrile is pointed out. A number of literature strategies for treatment of addiction are addressed. However, no effective interventions are currently available. An hypothesis for addiction is offered based on ET and ROS at low concentrations. Radicals may aid in cell signaling entailing redox processes which influence ion transport, neuromodulation, and transcription. Ideas are suggested for future work dealing with health promotion. These include use of AOs, both dietary and supplemental, trapping of the norcocaine metabolite by non-toxic complexing agents, and use of nitrones for capturing harmful radical species.
As pyrroloquinoline quinone (PQQ) is a redox cofactor in mammals, we asked if it is cardioprotective. Rats were subjected to 2 h of left anterior descending (LAD) coronary artery ligation without reperfusion (model 1, ischemia). In model 2 (ischemia/reperfusion), rats were subjected to 17 or 30 min of LAD occlusion and 2 h of reperfusion. PQQ (15-20 mg/kg) was given i.p., either 30 min before LAD occlusion (Pretreatment) or i.v. at the onset of reperfusion (Treatment). In model 1, PQQ reduced infarct size (10.0 +/- 1.5 vs 19.1 +/- 2.1%, P < 0.01). In model 2, either PQQ Pretreatment or Treatment also reduced infarct size (18.4 +/- 2.3 and 25.6 +/- 3.5% vs 38.1 +/- 2.6%, P < 0.01). PQQ resulted in higher LV developed pressure and LV (+)dP/dt after 1-2 h of reperfusion (P < 0.05), and fewer ventricular fibrillation episodes. PQQ dose (5-20 mg/kg) was inversely related to infarct size. PQQ reduced myocardial tissue levels of malondialdehyde (MDA), an indicator of lipid peroxidation (316 +/- 88 vs 99 +/- 14 nmol/g, P < 0.01). PQQ given either as Pretreatment or as Treatment at the onset of reperfusion is highly effective in reducing infarct size and improving cardiac function in a dose-related manner in rat models of ischemia and ischemia/reperfusion. The optimal dose in this study, which exhibited neither renal nor hepatic toxicity, was 15 mg/kg, but lower doses may also be efficacious. We conclude that PQQ, which appears to act as a free radical scavenger in ischemic myocardium, is a highly effective cardioprotective agent.
Oxidative stress, i.e. imbalance between reactive oxygen species (ROS) and antioxidant defences, contributes to the progression of chronic heart failure (CHF). Acute inhibition of xanthine oxidase (XO), which produces ROS, improves mechanical efficiency of the failing heart, but whether long-term XO inhibition exerts beneficial effects in CHF is unknown.
In rats with established CHF induced by left coronary ligation, we assessed the effects of a 5-day and a 10-week treatment with the XO inhibitor allopurinol (50 mg kg(-1) day(-1)) on haemodynamics and left ventricular (LV) function and structure. Both acute and chronic allopurinol treatment increase cardiac output without modification of arterial pressure, but only chronic allopurinol treatment reduces LV end-diastolic pressure and LV relaxation constant. Chronic allopurinol treatment decreases both LV systolic and diastolic diameters, but acute allopurinol treatment only decreases LV systolic diameter. Moreover, chronic allopurinol decreases LV weight and collagen density. Despite XO inhibition after acute and chronic allopurinol treatment, as both treatments reduce uric acid plasma levels, only acute allopurinol treatment reduces LV ROS determined using electron spin resonance spectroscopy. However, the CHF-enhanced myocardial thiobarbituric acid reactive substances levels were never modified.
In experimental CHF, long-term allopurinol treatment, initiated in a pathological state of overt CHF, improves LV haemodynamics and function and prevents LV remodelling. These long-term effects are, at least partially, caused by a transient reduction of myocardial ROS shortly after initiation of allopurinol treatment, but whether other mechanism(s), independent of myocardial redox 'status', such as reduced inflammation, are implicated remains to be confirmed.
A new method of total RNA isolation by a single extraction with an acid guanidinium thiocyanate-phenol-chloroform mixture is described. The method provides a pure preparation of undegraded RNA in high yield and can be completed within 4 h. It is particularly useful for processing large numbers of samples and for isolation of RNA from minute quantities of cells or tissue samples.
Reactive oxygen species have emerged as important molecules in cardiovascular function. Recent work has shown that NAD(P)H oxidases are major sources of superoxide in vascular cells and myocytes. The biochemical characterization, activation paradigms, structure, and function of this enzyme are now partly understood. Vascular NAD(P)H oxidases share some, but not all, characteristics of the neutrophil enzyme. In response to growth factors and cytokines, they produce superoxide, which is metabolized to hydrogen peroxide, and both of these reactive oxygen species serve as second messengers to activate multiple intracellular signaling pathways. The vascular NAD(P)H oxidases have been found to be essential in the physiological response of vascular cells, including growth, migration, and modification of the extracellular matrix. They have also been linked to hypertension and to pathological states associated with uncontrolled growth and inflammation, such as atherosclerosis.
This study was designed to assess the parameters of myocardial oxidative stress and related cardiac morphological changes following intraperitoneal cocaine exposure in rats. The cardiac levels of reduced glutathione(GSH), oxidised glutathione(GSSG), ascorbic acid (AA), and the production of malondialdehyde (MDA) were measured, as well as the variations of activity in the enzyme systems involved in cell antioxidant defence, glutathione peroxidase (GSH-Px), glutathione reductase (GR) and superoxide dismutase (SOD). After chronic cocaine administration for 30 days GSH was significantly depleted in the heart from 30 min (P < 0.001) to 24 h (P < 0.001) after exposure, and GSSG was increased for a similar time (P < 0.05 at 30 min and P < 0.01 at 24 h). SOD increased during the first hour (P < 0.001), GR and GSH-Px both increased from 30 min to 24 h, and these increases were statistically significant (P < 0.01 and P < 0.001 at 30 min and P < 0.01 and P < 0.001 at 24 h, respectively). The AA levels increased after 1 h (P < 0.01), remaining significantly so for 24 h (P < 0.001) and MDA increased from 30 min to 24 h, all values being highly significant (P < 0.001). The body weight was significantly (P < 0.001) reduced in both cocaine groups (40 mg/kg x 30 days and 40 mg/kg x 10 days + 60 mg/kg x 20 days). The heart weight (P < 0.01) and its percentage of the body weight (P < 0.001) were significantly higher in these two groups than in the controls. Similarly, in the noradrenaline 4 mg/ kg x 30 days group, the body weight was significantly (P < 0.001) reduced and the heart weight (P < 0.01) and its percentage of body weight (P < 0.001) were significantly higher than in the controls. In comparing the cocaine and noradrenaline experiments, the frequency and extent of cardiac lesions obtained with 40 mg/kg x 10 days + 60 mg/kg x 20 days of cocaine were similar to those with 8 mg/kg of noradrenaline at 24 h. In this experimental model, cocaine administration compromised the antioxidant defence system of the heart associated with a significant increase of heart weight and the percentage of body weight.
Background:
Angiotensin II induces both cardiac and vascular smooth muscle (VSM) hypertrophy. Recent studies suggest a central role for a phagocyte-type NADPH oxidase in angiotensin II-induced VSM hypertrophy. The possible involvement of an NADPH oxidase in the development of cardiac hypertrophy has not been studied. Methods and Results- Mice with targeted disruption of the NADPH oxidase subunit gp91(phox) (gp91(phox-/-)) and matched wild-type mice were subjected to subcutaneous angiotensin II infusion at a subpressor dose (0.3 mg/kg/day) for 2 weeks. Systolic blood pressure was unaltered by angiotensin II in either group. Angiotensin II significantly increased heart/body weight ratio, atrial natriuretic factor and beta-myosin heavy chain mRNA expression, myocyte area, and cardiac collagen content in wild-type but not gp91(phox-/-) mice. Angiotensin II treatment increased myocardial NADPH oxidase activity in wild-type but not gp91(phox-/-) mice.
Conclusions:
A gp91(phox)-containing NADPH oxidase plays an important role in the development of angiotensin II-induced cardiac hypertrophy, independent of changes in blood pressure.
The past two decades have witnessed an explosive growth of knowledge regarding postischemic myocardial dysfunction or myocardial “stunning.” The purpose of this review is to summarize current information regarding the pathophysiology and pathogenesis of this phenomenon. Myocardial stunning should not be regarded as a single entity but rather as a “syndrome” that has been observed in a wide variety of experimental settings, which include the following: 1) stunning after a single, completely reversible episode of regional ischemia in vivo; 2) stunning after multiple, completely reversible episodes of regional ischemia in vivo; 3) stunning after a partly reversible episode of regional ischemia in vivo (subendocardial infarction); 4) stunning after global ischemia in vitro; 5) stunning after global ischemia in vivo; and 6) stunning after exercise-induced ischemia (high-flow ischemia). Whether these settings share a common mechanism is unknown. Although the pathogenesis of myocardial stunning has not been definitively established, the two major hypotheses are that it is caused by the generation of oxygen-derived free radicals (oxyradical hypothesis) and by a transient calcium overload (calcium hypothesis) on reperfusion. The final lesion responsible for the contractile depression appears to be a decreased responsiveness of contractile filaments to calcium. Recent evidence suggests that calcium overload may activate calpains, resulting in selective proteolysis of myofibrils; the time required for resynthesis of damaged proteins would explain in part the delayed recovery of function in stunned myocardium. The oxyradical and calcium hypotheses are not mutually exclusive and are likely to represent different facets of the same pathophysiological cascade. For example, increased free radical formation could cause cellular calcium overload, which would damage the contractile apparatus of the myocytes. Free radical generation could also directly alter contractile filaments in a manner that renders them less responsive to calcium (e.g., oxidation of critical thiol groups). However, it remains unknown whether oxyradicals play a role in all forms of stunning and whether the calcium hypothesis is applicable to stunning in vivo. Nevertheless, it is clear that the lesion responsible for myocardial stunning occurs, at least in part, after reperfusion so that this contractile dysfunction can be viewed, in part, as a form of “reperfusion injury.” An important implication of the phenomenon of myocardial stunning is that so-called chronic hibernation may in fact be the result of repetitive episodes of stunning, which have a cumulative effect and cause protracted postischemic dysfunction. A better understanding of myocardial stunning will expand our knowledge of the pathophysiology of myocardial ischemia and provide a rationale for developing new therapeutic strategies designed to prevent postischemic dysfunction in patients.
Background— The myocardial velocity gradient (MVG) is a recent index of regional myocardial function derived from endocardial and epicardial velocities obtained by tissue Doppler imaging (TDI). This index might be useful for discriminating between physiological and pathological left ventricular hypertrophy (LVH) and for documenting the early transition from compensated LVH to heart failure. We sought to compare MVG measured across the left ventricular posterior wall between normal rats and rats with physiological (exercise) and pathological (pressure-overload) LVH.
Methods and Results— Wistar rats were assigned to one of the following groups: sedentary, exercise (swimming), and 2-month or 9-month abdominal aortic banding. Compared with sedentary rats, exercise and 2-month banding led to similar and significant LVH. After 2-month banding, conventional parameters of systolic function (left ventricular fractional shortening and dP/dtmax) were not affected. However, systolic and diastolic MVG were similar in exercise and sedentary rats but were significantly lower in rats with aortic banding. Aortic debanding after 2 months led to a full recovery of MVG, whereas MVG remained decreased when debanding was performed after 9 months.
Conclusions— Myocardial contraction and relaxation assessed by TDI were impaired in pressure-overload LVH but not in exercise LVH. Therefore, TDI is more sensitive than conventional echocardiography for assessing myocardial dysfunction in pressure-overload LVH and for predicting early recovery in myocardial function after loading conditions normalization.
Background — Angiotensin II induces both cardiac and vascular smooth muscle (VSM) hypertrophy. Recent studies suggest a central role for a phagocyte-type NADPH oxidase in angiotensin II-induced VSM hypertrophy. The possible involvement of an NADPH oxidase in the development of cardiac hypertrophy has not been studied.
Methods and Results — Mice with targeted disruption of the NADPH oxidase subunit gp91 phox (gp91 phox−/− ) and matched wild-type mice were subjected to subcutaneous angiotensin II infusion at a subpressor dose (0.3 mg/kg/day) for 2 weeks. Systolic blood pressure was unaltered by angiotensin II in either group. Angiotensin II significantly increased heart/body weight ratio, atrial natriuretic factor and β-myosin heavy chain mRNA expression, myocyte area, and cardiac collagen content in wild-type but not gp91 phox−/− mice. Angiotensin II treatment increased myocardial NADPH oxidase activity in wild-type but not gp91 phox−/− mice.
Conclusions — A gp91 phox -containing NADPH oxidase plays an important role in the development of angiotensin II-induced cardiac hypertrophy, independent of changes in blood pressure.
Although researchers in radiation and cancer biology have known about the existence of free radicals and their potential role
in pathobiology for several decades, cardiac biologists only began to take notice of these noxious species in the 1970s. Exponential
growth of free radical research occurred after the discovery of superoxide dismutase in 1969. This antioxidant enzyme is responsible
for the dismutation of superoxide radical — a free radical chain initiator. A fine balance between free radicals and a variety
of endogenous antioxidants is believed to exist. Any disturbance in this equilibrium in favour of free radicals causes an
increase in oxidative stress and initiates subcellular changes leading to cardiomyopathy and heart failure. Our knowledge
about the role of free radicals in the pathogenesis of cardiac dysfunction is fast approaching the point where newer therapies
employing antioxidants are in sight.
OBJECTIVES
We administered antioxidant vitamins to rabbits with pacing-induced cardiomyopathy to assess whether antioxidant therapy retards the progression of congestive heart failure (CHF).BACKGROUND
Although oxidative stress is increased in CHF, whether progression of heart failure could be prevented or reduced by antioxidants is not known.METHODS
Rabbits with chronic cardiac pacing and sham operation were randomized to receive a combination of beta-carotene, ascorbic acid and alpha-tocopherol, alpha-tocopherol alone or placebo over eight weeks. Echocardiography was used to measure cardiac function weekly. Resting hemodynamics and in vivo myocardial beta-adrenergic responsiveness were studied at week 8. Animals were then sacrificed for measuring myocardial beta-receptor density, norepinephrine (NE) uptake-1 site density, sympathetic neuronal marker profiles, tissue-reduced glutathione/oxidized glutathione (GSH/GSSG) ratio and oxidative damage of mitochondrial DNA (mtDNA).RESULTSRapid cardiac pacing increased myocardial oxidative stress as evidenced by reduced myocardial GSH/GSSG ratio and increased oxidized mtDNA and produced cardiac dysfunction, beta-adrenergic subsensitivity, beta-receptor downregulation, diminished sympathetic neurotransmitter profiles and reduced NE uptake-1 carrier density. A combination of antioxidant vitamins reduced the myocardial oxidative stress, attenuated cardiac dysfunction and prevented myocardial beta-receptor downregulation and sympathetic nerve terminal dysfunction. Administration of alpha-tocopherol alone produced similar effects, but the effects were less marked than those produced by the three vitamins together. Vitamins produced no effects in sham-operated animals.CONCLUSIONS
Antioxidant vitamins reduced tissue oxidative stress in CHF and attenuated the associated cardiac dysfunction, beta-receptor downregulation and sympathetic nerve terminal abnormalities. The findings suggest that antioxidant therapy may be efficacious in human CHF.
Recent studies have shown that oxidative stress plays an important role in cardiovascular diseases. NADPH oxidase is one of the major sources of superoxide anions and a candidate for the initiation and development of atherosclerosis, which involves the remodeling of vasculature. However, the relevance of NADPH oxidase in ventricular remodeling has not been well-characterized. This is the first report showing that the expression of p22-phox and gp91-phox, essential components of NADPH oxidase, are increased in the infarcted sites after myocardial infarction. The levels of thiobarbituric acid reactive substance, which indicates the lipid peroxidation level, and nuclear factor-κB (NF-κB) DNA binding activity are also increased in infarcted sites. Our results suggest that the increased expression of NADPH oxidase may have an effect on left ventricular remodeling by increasing the redox-sensitive NF-κB DNA binding activity as well as the lipid peroxidation level.
This chapter discusses the preparation and assay of superoxide dismutase (SOD). SODs are found in all oxygen-utilizing organisms and constitute a defense against oxygen toxicity. SODs were first isolated from erythrocytes as a copper protein of unknown function. Thus, some SODs contain copper and zinc, others contain manganese, and still others contain iron. Assay techniques for each of these enzymes are similar, but distinct isolation procedures are used in their purification. Most mammalian tissues contain both a cuprozinc and a mangano superoxide dismutase. SODs are unique among enzymes in that their substrate is an unstable free radical. This complicates the measurement of their catalytic activity. Convenient assays of SODs have necessarily been of the indirect type. Such assays consist of two components: a superoxide generator and a superoxide detector. The control reaction rate can be completely inhibited by large amounts of SOD if a xanthine oxidase of high quality is being used. Partially degraded xanthine oxidase can, to a small extent, reduce cytochrome c by a nonsuperoxide mediated mechanism.
It is clear that cocaine has cardiotoxic effects. Acute doses of cocaine suppress myocardial contractility, reduce coronary caliber and coronary blood flow, induce electrical abnormalities in the heart, and in conscious preparations increase heart rate and blood pressure. These effects will decrease myocardial oxygen supply and may increase demand (if heart rate and blood pressure rise). Thus, myocardial ischemia and/or infarction may occur, the latter leading to large areas of confluent necrosis. Increased platelet aggregability may contribute to ischemia and/or infarction. Young patients who present with acute myocardial infarction, especially without other risk factors, should be questioned regarding use of cocaine. As recently pointed out by Cregler, cocaine is a new and sometimes unrecognized risk factor for heart disease. Acute depression of LV function by cocaine may lead to the presence of a transient cardiomyopathic presentation. Chronic cocaine use can lead to the above problems as well as to acceleration of atherosclerosis. Direct toxic effects on the myocardium have been suggested, including scattered foci of myocyte necrosis (and in some but not all studies, contraction band necrosis), myocarditis, and foci of myocyte fibrosis. These abnormalities may lead to cases of cardiomyopathy. Left ventricular hypertrophy associated with chronic cocaine recently has been described. Arrhythmias and sudden death may be observed in acute or chronic use of cocaine. Miscellaneous cardiovascular abnormalities include ruptured aorta and endocarditis. Most of the cardiac toxicity with cocaine can be traced to two basic mechanisms: one is its ability to block sodium channels, leading to a local anesthetic or membrane-stabilizing effect; the second is its ability to block reuptake of catecholamines in the presynaptic neurons in the central and peripheral nervous system, resulting in increased sympathetic output and increased catecholamines. Other potential mechanisms of cocaine cardiotoxicity include a possible direct calcium effect leading to contraction of vessels and contraction bands in myocytes, hypersensitivity, and increased platelet aggregation (which may be related to increased catecholamine). The correct therapy for cocaine cardiotoxicity is not known. Calcium blockers, alpha-blockers, nitrates, and thrombolytic therapy show some promise for acute toxicity. Beta-Blockade is controversial and may worsen coronary blood flow. In patients who develop cardiomyopathy, the usual therapy for this entity is appropriate.
This study was performed to determine whether chronic cocaine abuse is associated with left ventricular hypertrophy in humans.
A consecutive series of 40 chronic cocaine abusers 23-44 years old who were enrolled in an inpatient drug rehabilitation program were considered for the study. Subjects with elevated resting blood pressure (n = 4) or a history of hypertension (n = 3) were excluded. Technically adequate two-dimensional echocardiograms were obtained in 30 cocaine abusers and 30 age- and race-matched normal control subjects. All subjects were men, and the groups were similar with regard to resting blood pressure, height, weight, and body surface area. All echocardiograms were read in blinded fashion, and left ventricular mass was calculated by the area-length method. Left ventricular cavity dimensions and wall motion were normal in all subjects. Left ventricular mass index was higher in the cocaine group (103 +/- 24 versus 77 +/- 14 g/m2, p = 0.0001). Posterior wall thickness was increased (1.2 cm or more) in 13 cocaine abusers (43%) compared with four controls (p = 0.0099).
Chronic cocaine abuse is associated with increased left ventricular mass index and wall thickness. Left ventricular hypertrophy may provide a substrate facilitating the development of myocardial ischemia and/or arrhythmias in cocaine abusers.
Publisher Summary This chapter presents a procedure for the preparation of glutathione peroxidase, which is regarded as a major protective system against endogenously and exogenously induced lipid peroxidation. Two types of methods are used for determining the activity of glutathione peroxidase. One involves a direct measurement of unconsumed glutathione (GSH) at fixed time periods by polarographic GSH analysis' (Method 1), or by the dithionitrobenzoic acid method (Method 2). The second approach takes advantage of the capability of glutathione reductase, with nicotinamide adenine dinucleotide phosphate (NADPH), to regenerate GSH from oxidized GSH. The decrease in NADPH is continuously measured spectrophotometrically, while the GSH concentration in the enzymatic cycle remains essentially constant (Method 3). A convenient source for the preparation of glutathione peroxidase is bovine blood including the following steps: hemolysate; organic solvent precipitation; phosphate precipitation; absorption to phenyl-sepharose; and washing on diethylaminoethyl (DEAE)–sephadex, S-300 sephacryl, and hydroxylapatite column.
Sources of superoxide anion (O2-.) production in calf pulmonary artery smooth muscle homogenate and subcellular fractions were examined in this study by measurement of the chemiluminescence produced by the reaction of O2-. with 50 microM lucigenin, because recent evidence suggests that endogenously produced reactive O2 species appear to mediate certain vascular responses. In the homogenate fraction, an NADH (0.1 mM)-dependent oxidoreductase activity was the major detected source of chemiluminescence. NADPH (0.1 mM) produced only 3% of the O2-. observed with NADH. Quantitation of certain other potential sources of O2-. (under optimized conditions), including xanthine oxidase (0.1 mM hypoxanthine), mitochondria (5 mM succinate + 30 microM antimycin), cyclooxygenase/lipoxygenase (1 microM arachidonic acid + 0.1 mM NADPH), or autooxidation (0.1 mg/ml superoxide dismutase), resulted in the detection of minimal amounts (< 3% of NADH) of chemiluminescence. Estimation of mitochondrial O2-. production from tissue respiration rates suggests that lucigenin is a poor detector of intramitochondrial O2-.. These observations were confirmed by examination of chemiluminescence produced by subcellular fractions, where the major activity detected was an NADH oxidoreductase, which fractionated in a manner closely matching the activity of the microsomal marker enzyme rotenone-insensitive NADH-cytochrome c reductase. Because this NADH oxidoreductase appears to be a major vascular smooth muscle-derived source of O2-. production, this system has the potential to be an important endogenous source for the generation of vasoactive reactive O2 species.
Hypertrophy and heart failure were induced by placing a mildly constrictive band around the ascending aorta in young guinea pigs. Based on heart weight, left ventricular wall thickness, hemodynamic data, and other clinical signs, these animals were found to have physiological hypertrophy at 10 wk and congestive heart failure (CHF) at 20 wk. Hearts from these two groups of animals were examined for superoxide dismutase (SOD), glutathione peroxidase (GSHPx), and catalase activities as well as lipid peroxidation and glutathione [reduced glutathione (GSH)/oxidized glutathione (GSSG)] levels. There was an age-dependent increase in SOD activity and GSH content in sham controls. SOD activity was 28% higher in the 10-wk-hypertrophy group and 46% lower in the CHF group than in respective sham controls. GSHPx activity increased significantly in the hypertrophied hearts, whereas in the failing hearts, the activity was not different from the 20-wk controls but was significantly lower than in the hypertrophied hearts. Catalase activity did not change at either stage. GSH content in the hypertrophied hearts was significantly higher compared with sham controls. In the CHF group, GSH content was significantly lower and GSSG content was significantly higher than in sham controls. Lipid peroxidation, as indicated by malondialdehyde content, was significantly decreased in the hypertrophy group but increased toward control levels in the failure group. It is proposed that a relative deficit in myocardial antioxidant capacity as well as in the redox state may play a role in the pathogenesis of cardiac failure.
The effects of repeated cocaine administration on contractile responses were studied in adult rabbits. Repeated cocaine exposure caused a significant increase in the maximal response of the aorta to the agonists norepinephrine and serotonin as well as the receptor- independent stimulus KCl when compared to the saline controls. Cocaine exposure caused a significant increase in the wet weights of both heart and aorta. When the contraction was normalized to the wet weight of the aorta there was no difference between rabbits administered cocaine and saline. Acute cocaine administration caused a time-dependent increase in immunoreactivity of the proto-oncogene c-Fos in the aorta. These results show that repeated cocaine administration leads to the development of cardiovascular hypertrophy.
Lactate increases lucigenin chemiluminescence (CL)-detectable superoxide anion (O2.-) generation in bovine vascular smooth muscle and endothelium, and a microsomal flavoprotein-containing NADH oxidase whose activity is regulated by PO2 and cytosolic NAD(H) redox appears to be the detected source of O2.- production. Little is known about the importance of this O2.(-)-producing system in cardiac myocytes.
In isolated bovine cardiac myocytes, lactate (10 mmol/L) increased lucigenin-detectable O2.- levels to approximately 1.8 times baseline, whereas pyruvate (10 mmol/L) and mitochondrial probes did not increase the detection of O2.-. A nonmitochondrial NADH oxidase activity, found in microsomes containing a cytochrome b558, was a major source of O2.- production in the homogenate of myocytes, because NADH (0.1 mmol/L) increased basal lucigenin CL >100-fold. NADPH oxidases, mitochondria, and xanthine oxidase were minor sources of detectable O2.- production. However, mitochondria released H2O2 in the presence of 5 mmol/L succinate and 30 micromol/L antimycin, based on its detection as catalase-inhibitable luminol (+horseradish peroxidase)-elicited CL. Diphenyliodonium (DPI), an inhibitor of flavoprotein-containing oxidases, significantly attenuated basal, lactate, and NADH-elicited lucigenin CL. Hypoxia eliminated myocyte lucigenin CL, and posthypoxic reoxygenation caused an 8.6-fold increase in the detection of O2.- that was potentiated by lactate and inhibited by DPI.
NADH oxidase activity linked to cytosolic NAD(H) redox appears to be a key source of O2.- production in cardiac myocytes that could contribute to oxidant signaling mechanisms and injury upon exposure to changes in PO2 and metabolites produced under hypoxia, such as lactate. These processes could contribute to the previously observed potentiation of injury caused by lactate in cardiac ischemia/reperfusion.
As cocaine abuse has become widespread, it has been associated with various cardiovascular complications, including angina pectoris, myocardial infarction, and sudden cardiac death. Cocaine's principal effects on the cardiovascular system are mediated via alpha-adrenergic stimulation and include (1) an increase in the determinants of myocardial oxygen demand (heart rate and systemic arterial pressure), and (2) a concomitant decrease in myocardial oxygen supply (caused by vasoconstriction of the epicardial coronary arteries). beta-adrenergic blocking agents may exacerbate cocaine-induced coronary arterial vasoconstriction, thereby increasing the magnitude of myocardial ischemia. In contrast, nitroglycerin and verapamil reverse cocaine-induced hypertension and coronary arterial vasoconstriction; therefore, they are the agents of choice in treating patients with cocaine-associated chest pain.
Plasma levels of the vasoconstrictor peptide endothelin (ET) are increased in chronic heart failure (CHF), and ET levels are a major predictor of mortality in this disease. Thus, ET may play a deleterious role in CHF. The purpose of this study was to assess the effects of chronic treatment with the ET receptor antagonist bosentan in a rat model of CHF.
Rats were subjected to coronary artery ligation and were treated for 2 or 9 months with placebo or bosentan (30 or 100 mg x kg(-1) x d(-1)). Bosentan 100 mg x kg(-1) markedly increased survival (after 9 months: untreated, 47%; bosentan, 65%; P<.01). Throughout the 9-month treatment period, bosentan significantly reduced arterial pressure and heart rate. After 2 or 9 months of treatment, the ET antagonist reduced central venous pressure and left ventricular (LV) end-diastolic pressure as well as plasma catecholamines, urinary cGMP, and LV ventricular collagen density. Bosentan also reduced LV dilatation (evidenced at 2 months by a shift in the pressure/volume relationship ex vivo). Echocardiographic studies performed after 2 months showed that the ET antagonist reduced hypertrophy and increased contractility of the noninfarcted LV wall. The lower dose of bosentan (30 mg x kg(-1)), which had no major hemodynamic or structural effects, also had no effect on survival.
Long-term treatment with an ET antagonist markedly increases survival in this rat model of CHF. This increase in survival is associated with decreases in both preload and afterload and an increase in cardiac output as well as decreased LV hypertrophy, LV dilatation, and cardiac fibrosis. Thus, chronic treatment with ET antagonists such as bosentan might be beneficial in human CHF and might increase long-term survival in this disease.
Cocaine abuse induces severe cardiomyopathy. To investigate the molecular effects of acute and prolonged administration of cocaine, mRNAs encoding markers of either mechanical overload, as atrial natriuretic factor (ANF) and alpha- and beta-myosin heavy chains, or fibrosis as type I and III procollagens, were quantitated in the left ventricle of rats 4 h after one injection of cocaine (40 mg/kg, n = 7), or 14 (n = 15) and 28 days (n = 10) after chronic infusion of cocaine (40 mg/kg per day). Plasma cocaine and benzylecgonine concentrations were both significantly augmented during the infusion while plasma levels of triiodothyronine and thyroxine were lowered. Acute injection of cocaine induced ANF gene expression. Cocaine treatment during 28 days resulted in left ventricular hypertrophy (+ 20% after 24 days, P < 0.05) with normal blood pressure, associated with an accumulation of mRNAs encoding ANF and type I and III collagens (+66% and +55%, P < 0.05). Such a chronic treatment also induced a shift from the alpha- to the beta-myosin heavy chain gene expression (-40% and +50%, P < 0.05). In conclusion, cocaine activates markers of both hemodynamic overload and fibrosis. Such an activation may result from direct and/or indirect effects of the drug such as myocardial ischemia, mechanical overload and/or hypothyroidism.
The role of cocaine in cardiac ischemia and subsequent reversible and irreversible pathologic changes is well established. Nevertheless, the mechanisms leading to cardiac injury and irreversible cellular changes remain elusive. Reactive oxygen species (ROSs) are the critical mediators of cellular damage during ischemia-reperfusion. To explore the response of cardiac oxidative stress parameters to intravenous (i.v.) And intraperitoneal (i.p.) cocaine exposure, cardiac total glutathione (GSH, GSSG), malonaldialdehyde (MDA), Mn-superoxide dismutase (Mn-SOD), catalase (CAT), GSH-peroxidase (GSH-px), and GSH s-transferase (GST) were measured, along with biochemical and histologic markers indicative of cardiac injury. Repeated i.p. cocaine exposure produced significant impairment in cardiac integrity, demonstrated by increased circulating lactate (2.4-fold; p < 0.0001), creatine kinase (2.2-fold; p < 0.0001), and creatinine levels (1.7-fold; p < 0.0001). Infiltration of neutrophils into myocardial cavities also was evident. These changes paralleled increases in cardiac MDA (25%; p < 0.04), GSSG (55%; p < 0.001), protein carbonyls (23%; p < 0.05), and Mn-SOD (23%; p < 0.05) levels, indicative of oxidative stress, decreases in GSH (35%; p < 0.01), adenosine triphosphate (ATP; 26%; p < 0.04), GSH-px (28%; p < 0.03), CAT (32%; p < 0.01), and GST (50%; p < 0.001) levels. Intravenous cocaine administration also had similar effects on cardiac oxidative stress measures. In conclusion, our data indicate that cocaine administration compromised the heart's antioxidant defense system.
Angiotensin II activates NAD(P)H-dependent oxidases via AT1-receptor stimulation, the most important vascular source of superoxide (O2*-). The AT1 receptor is upregulated in vitro by low-density lipoprotein. The present study was designed to test whether hypercholesterolemia is associated with increased NAD(P)H-dependent vascular O2*- production and whether AT1-receptor blockade may inhibit this oxidase and in parallel improve endothelial dysfunction.
Vascular responses were determined by isometric tension studies, and relative rates of vascular O2*- production were determined by use of chemiluminescence with lucigenin, a cypridina luciferin analogue, and electron spin resonance studies. AT1-receptor mRNA was quantified by Northern analysis, and AT1-receptor density was measured by radioligand binding assays. Hypercholesterolemia was associated with impaired endothelium-dependent vasodilation and increased O2*- production in intact vessels. In vessel homogenates, we found a significant activation of NADH-driven O2*- production in both models of hyperlipidemia. Treatment of cholesterol-fed animals with the AT1-receptor antagonist Bay 10-6734 improved endothelial dysfunction, normalized vascular O2*- and NADH-oxidase activity, decreased macrophage infiltration, and reduced early plaque formation. In the setting of hypercholesterolemia, the aortic AT1 receptor mRNA was upregulated to 166+/-11%, accompanied by a comparable increase in AT1-receptor density.
Hypercholesterolemia is associated with AT1-receptor upregulation, endothelial dysfunction, and increased NADH-dependent vascular O2*- production. The improvement of endothelial dysfunction, inhibition of the oxidase, and reduction of early plaque formation by an AT1-receptor antagonist suggests a crucial role of angiotensin II-mediated O2*- production in the early stage of atherosclerosis.
Cocaine is thought to stimulate the cardiovascular system by blocking peripheral norepinephrine reuptake. This study was designed to test the novel hypotheses that cocaine also stimulates the human cardiovascular system by (1) increasing central sympathetic outflow, or (2) decreasing parasympathetic control of heart rate.
In 14 healthy cocaine-naive humans, we measured blood pressure, heart rate, and skin sympathetic nerve activity (SNA) with intraneural microelectrodes before, during, and for 90 minutes after intranasal cocaine (2 mg/kg, n=7) or lidocaine (2 mg/kg, n=7). Intranasal cocaine caused an initial but transient 3. 3-fold increase in skin SNA during the period of intranasal administration followed by a sustained 2.4-fold increase lasting for up to 90 minutes after cocaine. Unlike cocaine, intranasal lidocaine caused only a small transient increase in skin SNA due to local nasal irritation. The cocaine-induced increase in SNA was accompanied by decreased skin blood flow, increased skin vascular resistance, and increased heart rate. In 11 additional subjects, we showed that the cocaine-induced increase in heart rate was eliminated by beta-adrenergic receptor blockade (propranolol) but unaffected by muscarinic receptor blockade (atropine), indicating sympathetic mediation.
These studies provide direct microneurographic evidence in humans that intranasal cocaine stimulates central sympathetic outflow. This central sympathetic activation appears to be targeted not only to the cutaneous circulation promoting peripheral vasoconstriction but also to the heart promoting tachycardia.
Chronic excessive norepinephrine (NE) causes cardiac sympathetic nerve terminal abnormalities, myocardial beta-adrenergic receptor downregulation, and beta-adrenergic subsensitivity. The present study was carried out to determine whether these changes could be prevented by antioxidants.
Ferrets were administered either NE (1.33 mg/d) or vehicle by use of subcutaneous pellets for 4 weeks. Animals were simultaneously assigned to receive either antioxidant vitamins (beta-carotene, ascorbic acid, and alpha-tocopherol) or placebo pellets. NE increased plasma NE 4- to 5-fold but had no effect on heart rate, heart weight, arterial pressure, or left ventricular systolic function. However, myocardial NE uptake activity and NE uptake-1 site density were reduced, as well as cardiac neuronal NE, tyrosine hydroxylase, and neuropeptide Y. In addition, there was a decrease in myocardial beta-adrenergic receptor density with a selective decrease of the beta(1)-receptor subtype, reduction of the high-affinity site for isoproterenol, decreased basal adenylyl cyclase activity, and the adenylyl cyclase responses to isoproterenol, Gpp(NH)p, and forskolin. All of these changes were prevented by antioxidant vitamins. The effects of NE on myocardial beta-adrenergic receptor density, NE uptake-1 carrier site density, and neuronal NE were also prevented by superoxide dismutase or Trolox C.
The toxic effects of NE on the sympathetic nerve terminals are mediated via the formation of NE-derived oxygen free radicals. Preservation of the neuronal NE reuptake mechanism is functionally important, because the antioxidants also prevented myocardial beta-adrenergic receptor downregulation and postreceptor abnormalities. Thus, antioxidant therapy may be beneficial in heart failure, in which cardiac NE release is increased.
Emerging evidence indicates that reactive oxygen species, especially superoxide and hydrogen peroxide, are important signaling molecules in cardiovascular cells. Their production is regulated by hormone-sensitive enzymes such as the vascular NAD(P)H oxidases, and their metabolism is coordinated by antioxidant enzymes such as superoxide dismutase, catalase, and glutathione peroxidase. Both of these reactive oxygen species serve as second messengers to activate multiple intracellular proteins and enzymes, including the epidermal growth factor receptor, c-Src, p38 mitogen-activated protein kinase, Ras, and Akt/protein kinase B. Activation of these signaling cascades and redox-sensitive transcription factors leads to induction of many genes with important functional roles in the physiology and pathophysiology of vascular cells. Thus, reactive oxygen species participate in vascular smooth muscle cell growth and migration; modulation of endothelial function, including endothelium-dependent relaxation and expression of a proinflammatory phenotype; and modification of the extracellular matrix. All of these events play important roles in vascular diseases such as hypertension and atherosclerosis, suggesting that the sources of reactive oxygen species and the signaling pathways that they modify may represent important therapeutic targets.
Cocaine has been shown to activate the sympathoadrenal system in both animal and human studies. Controlled human studies have found inconclusive results regarding whether acute cocaine treatment elevates plasma epinephrine and norepinephrine concentrations. The purpose of this study was to investigate whether commonly abused doses of cocaine increase plasma epinephrine and norepinephrine concentrations in humans, in a double-blind, placebo-controlled study. Five male cocaine users were given an intravenous injection of 0.46 mg/kg dose of cocaine or placebo, on two consecutive days. Plasma epinephrine and norepinephrine concentrations were significantly increased in response to cocaine injection compared to placebo. Peak plasma epinephrine and norepinephrine concentrations were reached 3 and 12 min after cocaine injection, respectively. While changes in epinephrine levels following cocaine were correlated with systolic blood pressure and heart rate changes, changes in plasma norepinephrine were correlated with diastolic blood pressure and heart rate changes following cocaine administration. These results suggest that plasma epinephrine and norepinephrine can be used as a measure for cocaine induced sympathoadrenal system activation.
Lead exposure related oxidative stress has been incriminated, at least in part, to its toxic effects in different organs. The present investigation was carried out to study the ameliorative effects of antioxidant (ascorbic acid, alpha tocopherol or L-methionine) alone and antioxidant (alpha tocopherol) plus a conventional chelator (CaNa2 EDTA) on some of the parameters indicative of oxidative stress in the liver, kidney and brain in lead-exposed rats. Rats were given 0 (n=6, healthy controls) or 1 mg of Pb(2+)/kg b.w (n=30) as lead acetate solution in sterile normal saline ip for a period of 4 weeks. The ip injections were then withdrawn and lead exposed rats were randomly divided into five equal groups. Six lead-exposed rats were given no treatment during the 5th week (Pb group) to serve as positive controls. The rest four groups received either ascorbic acid, alpha tocopherol or L-methionine in the 5th week at the daily dose of 100 mg/kg b.w orally or alpha tocopherol as above plus CaNa2 EDTA at the rate of 110 mg/kg b.w twice a day ip for a period of 4 days. All the animals were sacrificed 1 day after the end of the experiment, and the liver, kidney and brain were quickly excised for the estimation of lead burden and alteration in the oxidative indices. Lead exposure for a period of 4 weeks followed by a period of 1 week to recover, resulted in significantly (P<0.05) higher accumulation of lead, associated with significant (P<0.05) increases in lipid peroxide level in the liver and brain, and non-protein bound thiol contents in the brain. Changes in the superoxide dismutase and catalase activities in lead-exposed rats did not reach statistical (P<0.05) significance. Treatment with antioxidants alone resulted in reversal of oxidative stress without significant decline in tissue lead burden. Tissue specific changes, following lead exposure and responses to the treatment with different antioxidants were recorded in the parameters of oxidative damage viz. lipid peroxide level, antioxidant enzymes and thiol contents.
Although an excessive amount of circulating catecholamines is known to induce cardiomyopathy, the mechanisms are poorly understood. This study was undertaken to investigate the role of oxidative stress in catecholamine-induced heart dysfunction. Treatment of rats for 24 h with a high dose (40 mg/kg) of a synthetic catecholamine, isoproterenol, resulted in increased left ventricular end diastolic pressure, depressed rates of pressure development, and pressure decay as well as increased myocardial Ca2+ content. The increased malondialdehyde content, as well as increased formation of conjugated dienes and low glutathione redox ratio were also observed in hearts from animals injected with isoproterenol. Furthermore, depressed cardiac sarcolemmal (SL) ATP-dependent Ca2+ uptake, Ca2+-stimulated ATPase activity, and Na+-dependent Ca2+ accumulation were detected in experimental hearts. All these catecholamine-induced changes in the heart were attenuated by pretreatment of animals with vitamin E, a well-known antioxidant (25 mg/kg/day for 2 days). Depressed cardiac performance, increased myocardial Ca2+ content, and decreased SL ATP-dependent, and Na+-dependent Ca2+ uptake activities were also seen in the isolated rat hearts perfused with adrenochrome, a catecholamine oxidation product (10 to 25 microg/ml). Incubation of SL membrane with different concentrations of adrenochrome also decreased the ATP-dependent and Na+-dependent Ca2+ uptake activities. These findings suggest the occurrence of oxidative stress, which may depress the SL Ca2+ transport and result in the development intracellular Ca2+ overload and heart dysfunction in catecholamine-induced cardiomyopathy.
Enhanced vascular superoxide anion generation contributes to endothelial dysfunction in heart failure. However, the effect of long-term treatment with the antioxidant vitamin E is unknown.
Relaxant responses were determined in aortic rings from Wistar rats with heart failure 12 weeks after myocardial infarction (MI) and compared with responses in tissues from sham-operated animals. From the seventh post-operative day, rats were given either a standard chow or a chow enriched in vitamin E (approximate intake 100 mg/day). In rings from rats with heart failure, acetylcholine-induced relaxation was attenuated (maximum relaxation, R(max) 54 +/- 3%) when compared with rings from sham-operated animals (79 +/- 3%, n=12, P < 0.01), while endothelium-independent relaxation elicited by sodium-nitroprusside was unchanged. Aortic superoxide generation was significantly enhanced in rats with heart failure. Vitamin E supplementation significantly improved acetylcholine-induced relaxation in rats with heart failure (R(max) 75 +/- 4%, P < 0.01) and led to a leftward shift in sodium-nitroprusside-induced relaxation curve. Aortic expression of the beta(1)-subunit of soluble guanylyl cyclase was significantly enhanced by vitamin E supplementation. In addition, the elevated vascular superoxide formation was normalised by vitamin E.
These results demonstrate that dietary supplementation with the antioxidant vitamin E restores normal endothelial function, reduces vascular superoxide anion formation and increases the expression of the soluble guanylyl cyclase in rats with heart failure.
The deaths of several celebrities in recent years in association with the nontherapeutic use of cocaine have focused widespread attention on the problem of cocaine abuse. In 1999, an estimated 25 million Americans admitted that they had used cocaine at least once; 3.7 million had used it within the previous year; and 1.5 million were current users. During the same year, cocaine was mentioned in 30 percent of all drug-related visits to emergency departments.1 Cocaine is the most commonly used illicit drug among subjects seeking care in hospital emergency departments or drug-treatment centers. In addition, it is the most frequent . . .
Ascorbic acid (vitamin C) and alpha-tocopherol (vitamin E) have antioxidant properties that could improve redox-sensitive vascular changes associated with hypertension. We determined whether vitamins C and E influence vascular function and structure in hypertension by modulating activity of NADPH oxidase and superoxide dismutase (SOD). Adult stroke-prone spontaneously hypertensive rats (SHRSP) were divided into 3 groups: control (C; n=6), vitamin C-treated (vit C, 1000 mg/day; n=7), and vitamin E-treated (vit E, 1000 IU/day; n=8). All rats were fed 4% NaCl. Blood pressure was measured weekly. After 6 weeks of treatment, the rats were killed, and mesenteric arteries were mounted as pressurized preparations. Vascular O(2)(-) generation and NADPH oxidase activity were measured by chemiluminescence. Vascular SOD activity and plasma total antioxidant status (TAS) were determined spectrophotometrically. Blood pressure increased from 212+/-7 to 265+/-6 mm Hg in controls. Treatment prevented progression of hypertension (vit C, 222+/-6 to 234+/-14 mm Hg; vit E, 220+/-9 to 227+/-10 mm Hg). Acetylcholine-induced vasodilation was improved (P<0.05), and media-to-lumen ratio was reduced (P<0.05) in the treated rats. O(2)(-) was lower in vitamin-treated groups compared with controls (vit C, 10+/-4 nmol. min(-1). g(-1) dry tissue weight; vit E, 9.6+/-3.5 nmol. min(-1). g(-1) dry tissue weight; C, 21+/-9 nmol. min(-1). g(-1) dry tissue weight; P<0.05). Both vitamin-treated groups showed significant improvement (P<0.01) in TAS. These effects were associated with decreased activation of vascular NADPH oxidase (vit C, 46+/-10; vit E, 50+/-9; C, 70+/-16 nmol. min(-1). g(-1) dry tissue weight, P<0.05) and increased activation of SOD (vit C, 12+/-2; vit E, 8+/-1; C, 4.6+/-1 U/mg; P<0.05). Our results demonstrate that vitamins C and E reduce oxidative stress, improve vascular function and structure, and prevent progression of hypertension in SHRSP. These effects may be mediated via modulation of enzyme systems that generate free radicals.
Endothelium-derived nitric oxide (NO) selectively enhances myocardial relaxation. In experimental left ventricular hypertrophy (LVH), this endothelium-dependent LV relaxant response is impaired despite a preserved response to exogenous NO. We investigated the potential role of reactive oxygen species (ROS) in this defect.
Short-term treatment with the antioxidants vitamin C (10 micromol/L) or deferoxamine (500 micromol/L) restored LV relaxant responses to the NO agonists bradykinin (10 nmol/L) and substance P (100 nmol/L) in isolated ejecting hearts of aortic-banded guinea pigs. Substance P decreased the time to onset of LV relaxation (tdP/dt(min)) by -6.8+/-1.7 ms in the presence of vitamin C and by -8.9+/-2.2 ms in the presence of deferoxamine compared with -0.8+/-2.2 ms in the absence of antioxidants (P<0.05 either antioxidant versus control). A similar restoration of relaxant response to substance P was observed in the presence of the superoxide dismutase mimetic, Mn(III)tetrakis(1-methyl-4-pyridyl)porphyrin pentachloride (10 micromol/L), but not with tetrahydrobiopterin or L-arginine. Protein expression of the NADPH oxidase subunits gp91-phox and p67-phox and myocardial NADPH oxidase activity were significantly increased (P<0.05) in the banded group compared with shams.
An increase in ROS, most likely derived at least in part from NADPH oxidase, is responsible for the impaired endothelial regulation of LV relaxation in LVH. These are the first data to potentially link increased NADPH oxidase-derived ROS with a defect in cardiac contractile function in a pathological setting.
alpha-Tocopherol (the major vitamin E component) regulates key cellular events by mechanisms unrelated with its antioxidant function. Inhibition of protein kinase C (PKC) activity and vascular smooth muscle cell growth by alpha-tocopherol was first described by our group. Later, alpha-tocopherol was shown to inhibit PKC in various cell types with consequent inhibition of aggregation in platelets, of nitric oxide production in endothelial cells and of superoxide production in neutrophils and macrophages. alpha-Tocopherol diminishes adhesion molecule, collagenase and scavenger receptor (SR-A and CD36) expression and increases connective tissue growth factor expression.
Increased reactive oxygen species (ROS) production is implicated in the pathophysiology of left ventricular (LV) hypertrophy and heart failure. However, the enzymatic sources of myocardial ROS production are unclear. We examined the expression and activity of phagocyte-type NADPH oxidase in LV myocardium in an experimental guinea pig model of progressive pressure-overload LV hypertrophy. Concomitant with the development of LV hypertrophy, NADPH-dependent O2- production in LV homogenates, measured by lucigenin (5 micro mol/L) chemiluminescence or cytochrome c reduction assays, significantly and progressively increased (by approximately 40% at the stage of LV decompensation; P<0.05). O2- production was fully inhibited by diphenyleneiodonium (100 micromol/L). Immunoblotting revealed a progressive increase in expression of the NADPH oxidase subunits p22(phox), gp91(phox), p67(phox), and p47(phox) in the LV hypertrophy group, whereas immunolabeling studies indicated the presence of oxidase subunits in cardiomyocytes and endothelial cells. In parallel with the increase in O2- production, there was a significant increase in activation of extracellular signal-regulated kinase 1/2, extracellular signal-regulated kinase 5, c-Jun NH2-terminal kinase 1/2, and p38 mitogen-activated protein kinase. These data indicate that an NADPH oxidase expressed in cardiomyocytes is a major source of ROS generation in pressure overload LV hypertrophy and may contribute to pathophysiological changes such as the activation of redox-sensitive kinases and progression to heart failure.
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