[Show abstract][Hide abstract] ABSTRACT: IntroductionDengue Shock Syndrome (DSS) fluid resuscitation following the World Health Organization (WHO) guideline usually required large volumes of Ringer Lactate (RL) that may induce secondary fluid-overload. Our objective was to compare the effectiveness of the recommended volume of RL versus a smaller volume of a Hypertonic Sodium Lactate solution (HSL) in children suffering DSS. The primary endpoint was to evaluate the effect of HSL on endothelial cell inflammation, assessed by Soluble Vascular Cell Adhesion Molecule-1 (sVCAM-1) measurements. Secondarily, we considered the effectiveness of HSL in restoring hemodynamic fluid balance, acid¿base status, sodium and chloride balances as well as in-hospital survival.MethodsA prospective randomized single blind clinical trial including 50 DSS children conducted in the Pediatrics Department of Hasan Sadikin Hospital, Bandung, Indonesia. Only pediatric patients (2 to 14 year old) fulfilling the WHO criteria for DSS and new to resuscitation treatments were eligible. Patients were resuscitated with either HSL (5 ml.Kg BW¿1 in 15 minutes followed by 1 ml.Kg BW¿1.h¿1 for 12 hours), or RL (20 ml.Kg BW¿1 in 15 minutes followed by decreasing doses of 10, 7, 5, 3 ml.Kg BW¿1.h¿1 for 12 hours).ResultsIn total, 50 patients were randomized and included in outcome and adverse event analysis; 46 patients (8.2¿±¿0.5 years; 24.9¿±¿1.9 Kg; mean¿±¿sem) completed the protocol and were fully analyzed (24 and 22 subjects in the HSL and RL group respectively). Baseline (pre-bolus) data were similar in both groups. Hemodynamic recovery, plasma expansion, clinical outcome and survival rate were not significantly different in the two groups, whereas fluid accumulation was one third lower in the HSL than in the RL group. Moreover, HSL was responsible for a partial recovery from endothelial dysfunction, as indicated by the significant decrease in sVCAM-1.Conclusion
Similar hemodynamic shock recovery and plasma expansion were achieved in both groups despite much lower fluid intake and fluid accumulation in the HSL group.Trial RegistrationClinicalTrials.gov NCT00966628. Registered 26 August 2009.
[Show abstract][Hide abstract] ABSTRACT: This study aims to test the hypothesis whether lowering glycemia improves mitochondrial function and thereby attenuates apoptotic cell death during resuscitated murine septic shock.
Immediately and 6 h after cecal ligation and puncture (CLP), mice randomly received either vehicle or the anti-diabetic drug EMD008 (100 μg · g(-1)). At 15 h post CLP, mice were anesthetized, mechanically ventilated, instrumented and rendered normo- or hyperglycemic (target glycemia 100 ± 20 and 180 ± 50 mg · dL(-1), respectively) by infusing stable, non-radioactive isotope-labeled (13)C6-glucose. Target hemodynamics was achieved by colloid fluid resuscitation and continuous i.v. noradrenaline, and mechanical ventilation was titrated according to blood gases and pulmonary compliance measurements. Gluconeogenesis and glucose oxidation were derived from blood and expiratory glucose and (13)CO2 isotope enrichments, respectively; mathematical modeling allowed analyzing isotope data for glucose uptake as a function of glycemia. Postmortem liver tissue was analyzed for HO-1, AMPK, caspase-3, and Bax (western blotting) expression as well as for mitochondrial respiratory activity (high-resolution respirometry).
Hyperglycemia lowered mitochondrial respiratory capacity; EMD008 treatment was associated with increased mitochondrial respiration. Hyperglycemia decreased AMPK phosphorylation, and EMD008 attenuated both this effect as well as the expression of activated caspase-3 and Bax. During hyperglycemia EMD008 increased HO-1 expression. During hyperglycemia, maximal mitochondrial oxidative phosphorylation rate was directly related to HO-1 expression, while it was unrelated to AMPK activation. According to the mathematical modeling, EMD008 increased the slope of glucose uptake plotted as a function of glycemia.
During resuscitated, polymicrobial, murine septic shock, glycemic control either by reducing glucose infusion rates or EMD008 improved glucose uptake and thereby liver tissue mitochondrial respiratory activity. EMD008 effects were more pronounced during hyperglycemia and coincided with attenuated markers of apoptosis. The effects of glucose control were at least in part due to the up-regulation of HO-1 and activation of AMPK.
[Show abstract][Hide abstract] ABSTRACT: Acute heart failure (AHF) is characterized by inadequate cardiac output (CO), congestive symptoms, poor peripheral perfusion and end organ dysfunction. Treatment often includes a combination of diuretics, oxygen, positive pressure ventilation, inotropes and vasodilators or vasopressors. Lactate is a marker of illness severity but is also an important metabolic substrate for the myocardium at rest and during stress. We tested the effects of half-molar sodium lactate infusion on cardiac performance in AHF.
A prospective, randomized, controlled, open label, pilot clinical trial in 40 patients fulfilling two out of three criteria for AHF: 1) left ventricular ejection fraction (LVEF) < 40%, 2) acute pulmonary oedema or respiratory failure of predominantly cardiac origin requiring mechanical ventilation, 3) receiving vasopressor/inotropic support. Patients in the intervention group received 3 ml/kg bolus over 15 min of half-molar sodium lactate followed by 1 ml/kg/h continuous infusion for 24 h. The control group received only 3 ml/kg bolus of Hartman's solution without continuous infusion. The primary outcome was CO assessed by transthoracic echocardiography 24 hours post randomization. Secondary outcomes included a measure of right ventricular systolic function (tricuspid annular plane systolic excursion-TAPSE), acid base, electrolyte and organ function parameters along with length of stay and mortality.
The infusion of half-molar sodium lactate increased CO from 4.05 +/- 1.37 L/min to 5.49 +/- 1.9 L/min, (P < 0.01) and TAPSE from 14.7 +/- 5.5 mm to 18.3 +/- 7 mm, (P = 0.02). Plasma sodium and pH increased (136 +/- 4 to 146 +/- 6 and 7.40 +/- 0.06 to 7.53 +/- 0.03, respectively, both P < 0.01) while potassium, chloride and phosphate levels decreased. There were no significant differences in the need of vasoactive therapy, respiratory support, renal or liver function tests, duration of ICU and hospital stay or 28 and 90 day mortality.
Infusion of half-molar sodium lactate improved cardiac performance and led to metabolic alkalosis in AHF patients without any detrimental effect on organ function.Trial registration: Clinicaltrials.gov NCT01981655.
Full-text · Article · Mar 2014 · Critical care (London, England)
[Show abstract][Hide abstract] ABSTRACT: Purpose:
Preventive treatments of traumatic intracranial hypertension are not yet established. We aimed to compare the efficiency of half-molar sodium lactate (SL) versus saline serum solutions in preventing episodes of raised intracranial pressure (ICP) in patients with severe traumatic brain injury (TBI).
This was a double-blind, randomized controlled trial including 60 patients with severe TBI requiring ICP monitoring. Patients were randomly allocated to receive a 48-h continuous infusion at 0.5 ml/kg/h of either SL (SL group) or isotonic saline solution (control group) within the first 12 h post-trauma. Serial measurements of ICP, as well as fluid, sodium, and chloride balance were performed over the 48-h study period. The primary outcome was the number of raised ICP (≥20 mmHg) requiring a specific treatment.
Raised ICP episodes were reduced in the SL group as compared to the control group within the 48-h study period: 23 versus 53 episodes, respectively (p < 0.05). The proportion of patients presenting raised ICP episodes was smaller in the SL group than in the saline group: 11 (36 %) versus 20 patients (66 %) (p < 0.05). Cumulative 48-h fluid and chloride balances were reduced in the SL group compared to the control group (both p < 0.01).
A 48-h infusion of SL decreased the occurrence of raised ICP episodes in patients with severe TBI, while reducing fluid and chloride balances. These findings suggest that SL solution could be considered as an alternative treatment to prevent raised ICP following severe TBI.
No preview · Article · Jun 2013 · Intensive Care Medicine
[Show abstract][Hide abstract] ABSTRACT: Ethanol induces brain injury by a mechanism that remains partly unknown. Mitochondria play a key role in cell death processes, notably through the opening of the permeability transition pore (PTP). Here, we tested the effect of ethanol and PTP inhibitors on mitochondrial physiology and cell viability both in vitro and in vivo. Direct addition of ethanol up to 100 mM on isolated mouse brain mitochondria slightly decreased oxygen consumption but did not affect PTP regulation. In comparison, when isolated from ethanol-treated (two doses of 2 g/kg, 2 hours apart) 7-day-old mouse pups, brain mitochondria displayed a transient decrease in oxygen consumption but no change in PTP regulation or H2O2 production. Conversely, exposure of primary cultured astrocytes and neurons to 20 mM ethanol for 3 days led to a transient PTP opening in astrocytes without affecting cell viability, and to a permanent PTP opening in 10 to 20% neurons with the same percentage of cell death. Ethanol-treated mouse pups displayed a widespread caspase-3 activation in neurons but not in astrocytes, and dramatic behavioral alterations. Interestingly, two different PTP inhibitors (namely cyclosporin A and nortriptyline) prevented both ethanol-induced neuronal death in vivo and ethanol-induced behavioral modifications. We conclude that PTP opening is involved in ethanol-induced neurotoxicity in the mouse.
No preview · Article · Dec 2012 · Chemical Research in Toxicology
[Show abstract][Hide abstract] ABSTRACT: This study aimed at determining whether glucose-insulin-potassium (GIK) solutions modify the NADH/NAD(+) ratio during postischemic reperfusion and whether their cardioprotective effect can be attributed to this change in part through reduction of the mitochondrial reactive oxygen species (ROS) production. The hearts of 72 rats were perfused with a buffer containing glucose (5.5 mM) and hexanoate (0.5 mM). They were maintained in normoxia for 30 min and then subjected to low-flow ischemia (0.5% of the preischemic coronary flow for 20 min) followed by reperfusion (45 min). From the beginning of ischemia, the perfusate was subjected to various changes: enrichment with GIK solution, enrichment with lactate (2 mM), enrichment with pyruvate (2 mM), enrichment with pyruvate (2 mM) plus ethanol (2 mM), or no change for the control group. Left ventricular developed pressure, heart rate, coronary flow, and oxygen consumption were monitored throughout. The lactate/pyruvate ratio of the coronary effluent, known to reflect the cytosolic NADH/NAD(+) ratio and the fructose-6-phosphate/dihydroxyacetone-phosphate (F6P/DHAP) ratio of the reperfused myocardium, were evaluated. Mitochondrial ROS production was also estimated. The GIK solution improved the recovery of mechanical function during reperfusion. This was associated with an enhanced cytosolic NADH/NAD(+) ratio and reduced mitochondrial ROS production. The cardioprotection was also observed when the hearts were perfused with fluids known to increase the cytosolic NADH/NAD(+) ratio (lactate, pyruvate plus ethanol) compared with the other fluids (control and pyruvate groups). The hearts with a high mechanical recovery also displayed a low F6P/DHAP ratio, suggesting that an accelerated glycolysis rate may be responsible for increased cytosolic NADH production. In conclusion, the cardioprotection induced by GIK solutions could occur through an increase in the cytosolic NADH/NAD(+) ratio, leading to a decrease in mitochondrial ROS production.
[Show abstract][Hide abstract] ABSTRACT: Inhibition of the mitochondrial permeability transition pore (PTP) has proved to be an effective strategy for preventing oxidative stress-induced cell death, and the pore represents a viable cellular target for drugs. Here, we report that inhibition of complex I by rotenone is more effective at PTP inhibition than cyclosporin A in tissues that express low levels of the cyclosporin A mitochondrial target, cyclophilin D; and, conversely, that tissues in which rotenone does not affect the PTP are characterized by high levels of expression of cyclophilin D and sensitivity to cyclosporin A. Consistent with a regulatory role of complex I in the PTP-inhibiting effects of rotenone, the concentrations of the latter required for PTP inhibition precisely match those required to inhibit respiration; and a similar effect is seen with the antidiabetic drug metformin, which partially inhibits complex I. Remarkably (i) genetic ablation of cyclophilin D or its displacement with cyclosporin A restored PTP inhibition by rotenone in tissues that are otherwise resistant to its effects; and (ii) rotenone did not inhibit the PTP unless phosphate was present, in striking analogy with the phosphate requirement for the inhibitory effects of cyclosporin A [Basso et al. (2008) J. Biol. Chem. 283, 26307-26311]. These results indicate that inhibition of complex I by rotenone or metformin and displacement of cyclophilin D by cyclosporin A affect the PTP through a common mechanism; and that cells can modulate their PTP response to complex I inhibition by modifying the expression of cyclophilin D, a finding that has major implications for pore modulation in vivo.
Full-text · Article · May 2012 · Biochimica et Biophysica Acta
[Show abstract][Hide abstract] ABSTRACT: The permeability transition pore (PTP) is a mitochondrial inner membrane channel involved in cell death. The inhibition of PTP opening has been proved to be an effective strategy to prevent cell death induced by oxidative stress. Several ubiquinone analogs are known to powerfully inhibit PTP opening with an effect depending on the studied cell line. Here, we have studied the effects of ubiquinone 0 (Ub(0)), ubiquinone 5 (Ub(5)) and ubiquinone 10 (Ub(10)) on PTP regulation, H(2)O(2) production and cell viability in U937 cells. We found that Ub(0) induced both PTP opening and H(2)O(2) production. Ub(5) did not regulate PTP opening yet induced H(2)O(2) production. Ub(10) potently inhibited PTP opening yet induced H(2)O(2) production. Both Ub(0) and Ub(5) induced cell death, whereas Ub(10) was not toxic. Moreover, Ub(10) prevented tert-butyl hydroperoxide-induced PTP opening and subsequent cell death. We conclude that PTP-inhibitor ubiquinone analogs are able to prevent PTP opening-induced cell death only if they are not toxic per se, which is the case when they have no or low pro-oxidant activity.
Full-text · Article · Jan 2012 · Journal of Bioenergetics
[Show abstract][Hide abstract] ABSTRACT: Excess reactive oxygen species (ROS) production is thought to play a key role in the loss of pancreatic β-cell number and/or function, in response to high glucose and/or fatty acids. However, contradictory findings have been reported showing that in pancreatic β cells or insulin-secreting cell lines, ROS are produced under conditions of either high or low glucose. Superoxide production was measured in attached INS1E cells as a function of glucose concentration, by following in real time the oxidation of dihydroethidine. Minimal values of superoxide production were measured at glucose concentrations of 5-20 mM, whereas superoxide generation was maximal at 0-1 mM glucose. Superoxide generation started rapidly (15-30 min) after exposure to low glucose and was suppressed by its addition within minutes. Superoxide was totally suppressed by rotenone, but not myxothiazol, suggesting a role for complex I in this process. Indirect evidence for mitochondrial ROS generation was also provided by a decrease in aconitase activity. Activation of AMPK, a cellular metabolic sensor, and its downstream target ACC by low glucose concentration was largely inhibited by addition of MnTBAP, a MnSOD and catalase mimetic that also totally suppressed superoxide production. Taken together, the data show that low glucose activates AMPK in a superoxide-dependent, AMP-independent way.
Full-text · Article · Oct 2011 · Free Radical Biology and Medicine
[Show abstract][Hide abstract] ABSTRACT: Mitochondria are most important organelles in the survival of eukaryotic aerobic cells because they are the primary producers of ATP, regulators of ion homeostasis or redox state, and producers of free radicals. The key role of mitochondria in the generation of primordial ATP for the survival and proliferation of eukaryotic cells has been proven by extensive biochemical studies. In this context, it is crucial to understand the complexity of the mitochondrial compartment and its functionality and to develop experimental tools allowing the assessment of its nature and its function and metabolism. This review covers the role of the mitochondria in the cell, focusing on its structure, the mechanism of the mitochondrial respiratory chain, the maintenance of the transmembrane potential and the production of reactive oxygen species. The main probes used for mitochondrial compartment monitoring are described. In addition, various applications using mitochondrial-specific probes are detailed to illustrate the potential of flow and image cytometry in the study of the mitochondrial compartment. This review contains a panel of tools to explore mitochondria and to help researchers design experiments, determine the approach to be employed, and interpret their results.
[Show abstract][Hide abstract] ABSTRACT: The objective of this study was to determine the effects of cinnamon on glycogen synthesis, related gene expression, and protein levels in the muscle and liver using an animal model of insulin resistance, the high-fat/high-fructose (HF/HFr) diet-fed rat. Four groups of 22 male Wistar rats were fed for 12 weeks with (1) HF/HFr diet to induce insulin resistance, (2) HF/HFr diet containing 20 g cinnamon per kilogram of diet, (3) control diet, and (4) control diet containing 20 g cinnamon per kilogram of diet. In the liver, cinnamon added to the HF/HFr diet led to highly significant increases of liver glycogen. There were no significant changes in animals consuming the control diet plus cinnamon. In the liver, cinnamon also counteracted the decreases of the gene expressions due to the consumption of the HF/HFr diet for the insulin receptor, insulin receptor substrates 1 and 2, glucose transporters 1 and 2, and glycogen synthase 1. In muscle, the decreased expressions of these genes by the HF/HFr diet and glucose transporter 4 were also reversed by cinnamon. In addition, the overexpression of glycogen synthase 3β messenger RNA levels and protein observed in the muscle of HF/HFr fed rats was decreased in animals consuming cinnamon. These data demonstrate that, in insulin-resistant rats, cinnamon improves insulin sensitivity and enhances liver glycogen via regulating insulin signaling and glycogen synthesis. Changes due to cinnamon in control animals with normal insulin sensitivity were not significant.
Full-text · Article · May 2011 · Metabolism: clinical and experimental
[Show abstract][Hide abstract] ABSTRACT: Hyperglycemia is detrimental to β-cell viability, playing a major role in the progression of β-cell loss in diabetes mellitus. The permeability transition pore (PTP) is a mitochondrial channel involved in cell death. Recent evidence suggests that PTP inhibitors prevent hyperglycemia-induced cell death in human endothelial cells. In this work, we have examined the involvement of PTP opening in INS-1 cell death induced by high levels of glucose or fructose. PTP regulation was studied by measuring the calcium retention capacity in permeabilized INS-1 cells and by confocal microscopy in intact INS-1 cells. Cell death was analyzed by flow cytometry. We first reported that metformin and cyclosporin A (CsA) prevented Ca²+-induced PTP opening in permeabilized and intact INS-1 cells. We then showed that incubation of INS-1 cells in the presence of 30 mM glucose or 2.5 mM fructose induced PTP opening and led to cell death. As both metformin and CsA prevented glucose- and fructose- induced PTP opening, and hampered glucose- and fructose- induced cell death, we conclude that PTP opening is involved in high glucose- and high fructose- induced INS-1 cell death. We therefore suggest that preventing PTP opening might be a new approach to preserve β-cell viability.
Full-text · Article · Mar 2011 · Cell Death & Disease
[Show abstract][Hide abstract] ABSTRACT: A high-fat diet affects liver metabolism, leading to steatosis, a complex disorder related to insulin resistance and mitochondrial alterations. Steatosis is still poorly understood since diverse effects have been reported, depending on the different experimental models used.
We hereby report the effects of an 8 week high-fat diet on liver energy metabolism in a rat model, investigated in both isolated mitochondria and hepatocytes.
Liver mass was unchanged but lipid content and composition were markedly affected. State-3 mitochondrial oxidative phosphorylation was inhibited, contrasting with unaffected cytochrome content. Oxidative phosphorylation stoichiometry was unaffected, as were ATPase and adenine nucleotide translocator proteins and mRNAs. Mitochondrial acylcarnitine-related H(2)O(2) production was substantially higher and the mitochondrial quinone pool was smaller and more reduced. Cellular consequences of these mitochondrial alterations were investigated in perifused, freshly isolated hepatocytes. Ketogenesis and fatty acid-dependent respiration were lower, indicating a lower β-oxidation rate contrasting with higher RNA contents of CD36, FABP, CPT-1, and AcylCoA dehydrogenases. Concomitantly, the cellular redox state was more reduced in the mitochondrial matrix but more oxidized in the cytosol: these opposing changes are in agreement with a significantly higher in situ mitochondrial proton motive force.
A high-fat diet results in both a decrease in mitochondrial quinone pool and a profound modification in mitochondrial lipid composition. These changes appear to play a key role in the resulting inhibition of fatty acid oxidation and of mitochondrial oxidative-phosphorylation associated with an increased mitochondrial ROS production. Mitochondrial quinone pool could have prospects as a crucial event, potentially leading to interesting therapeutic perspectives.
No preview · Article · Feb 2011 · Journal of Hepatology
[Show abstract][Hide abstract] ABSTRACT: Comprendre la physiopathologie d’une hyperlactatémie passe par une connaissance étroite de son métabolisme. Le métabolisme du lactate est complexe, dépendant des différents organes et de leur condition énergétique. L’hyperlactatémie est depuis longtemps liée à la notion de déchet métabolique toxique, d’acidose lactique et d’hypoxie tissulaire. Toutes ces associations profondément ancrées dans nos esprits sont le plus souvent erronées. L’hyperlactatémie reste un bon signal d’alarme de crise énergétique, mais elle est aussi le témoin d’une adaptation métabolique. Dans certaines situations physiologiques et pathologiques, le lactate est un réel substrat énergétique.
[Show abstract][Hide abstract] ABSTRACT: La survie de notre organisme repose sur un ensemble de réactions nécessitant une consommation continue d’énergie. Pour couvrir ces besoins, nous devons puiser dans notre environnement des nutriments que nous allons transformer en source d’énergie. L’objet de ce chapitre est de décrire l’ensemble des réactions qui conduisent á la transformation et á l’utilisation de cette énergie.