Karine Laude

Publications of Karine Laude

• Targeted detoxification of selected reactive oxygen species in the vascular endothelium.

  Authors: Vladimir V Shuvaev, Melpo Christofidou-Solomidou, Faiz Bhora, Karine Laude, Hua Cai, Sergey Dikalov, Evguenia Arguiri, Charalambos C Solomides, Steven M Albelda, David G Harrison, Vladimir R Muzykantov

  The Journal of pharmacology and experimental therapeutics. 09/2009;

  Oxidative stress underlies diverse vascular diseases, but its management remains elusive, in part due to our inability to selectively detoxify reactive oxygen species (ROS) in pathological sites andOxidative stress underlies diverse vascular diseases, but its management remains elusive, in part due to our inability to selectively detoxify reactive oxygen species (ROS) in pathological sites and limited understanding which species need to be eliminated. The antioxidant enzymes (AOE) superoxide dismutase (SOD) and catalase (which decompose O2(.-) and H2O2, respectively) conjugated with an antibody to Platelet-Endothelial Cell Adhesion Molecule-1 (PECAM-1) bind to endothelial cells and alleviate oxidative stress in cell culture models. Here, we studied the effects of these antioxidant conjugates in mouse models of vascular oxidative stress. Anti-PECAM/catalase and anti-PECAM/SOD conjugates, in contrast to control IgG/AOE conjugates, accumulated in the lungs and vascularized organs after intravenous injection in wild type, but not PECAM KO mice. Anti-PECAM/catalase, but not anti-PECAM/SOD, protected mice from lung injury induced by H2O2 produced by glucose oxidase deposited in the pulmonary vasculature. Anti-PECAM/catalase also reduced alveolar edema and attenuated decline in arterial oxygen in mice that underwent unilateral lung ischemia/reperfusion, while anti-PECAM/SOD was not effective, implying key role of H2O2 in tissue damage in this pathology. In contrast, anti-PECAM/SOD, but not anti-PECAM/catalase prevented oxidation of tetrahydrobiopterin (BH4) and normalized vasoreactivity in the vessels of mice rendered hypertensive by pre-treatment with angiotensin-II. This outcome agrees with reports implicating superoxide and peroxynitrite in altered endothelium-dependent vasodilatation in hypertension. Therefore, the use of endothelial cell-targeted antioxidants identifies the key specific species of ROS involved in various forms of vascular disease and holds promise for the mechanistically-tailored treatment of these pathologies.

• Myocardial Dysfunction in Early State of Endotoxemia Role of Heme-Oxygenase-1.

  Authors: Fabienne Tamion, Fabrice Bauer, Vincent Richard, Karine Laude, Sylvanie Renet, Michel Slama, Christian Thuillez

  The Journal of surgical research. 10/2008;

  BACKGROUND: The triggers and cellular mechanisms of cardiac dysfunction have not been clearly established during the early period following challenge with lipopolysaccharides (LPS) (<1 h post-LPS).BACKGROUND: The triggers and cellular mechanisms of cardiac dysfunction have not been clearly established during the early period following challenge with lipopolysaccharides (LPS) (<1 h post-LPS). The aim of the study was to evaluate the myocardial depression during early stage of endotoxemia, the relationship between oxidative stress production and cardiac dysfunction in a rat model of endotoxic shock, and its inhibition by heme-oxygenase-1 (HO-1) overexpression. MATERIALS AND METHODS: LPS-induced myocardial deformation was assessed by tissue Doppler imaging and invasive hemodynamic measurements in rats 2 h after LPS challenge. Myocardial samples were processed for the measurements of tumor necrosis factor alpha (TNFalpha), nitric oxidase synthase II (NOSII), HO-1 gene expression, reactive oxygen species (ROS) production, and reduced glutathione/oxidized glutathione (GSH/GSSH) ratio. RESULTS: Myocardial systolic and diastolic deformation was evident as determined by tissue Doppler imaging but left ventricular conventional echocardiographic parameters did not show significant alterations. Myocardial deformation was significantly associated with reactive oxygen species and TNFalpha overproduction. Pretreatment with hemin to induce HO-1 resulted in decreased oxidative stress and TNFalpha production, and prevented LPS-induced alterations in myocardium. CONCLUSIONS: These preliminary results suggest myocardial alteration at a very early stage after LPS challenge associated with oxidative stress response. Manipulation of the HO-1 pathway may represent a future therapeutic strategy to counteract oxidative stress of endotoxemia and perhaps may limit future myocardial deformation.

• Mitochondrial pathophysiology, reactive oxygen species, and cardiovascular diseases.

  Authors: Ling Gao, Karine Laude, Hua Cai

  The Veterinary clinics of North America. Small animal practice. 02/2008; 38(1):137-55, vi.

  This article discusses mitochondrial pathophysiology, reactive oxygen species, and cardiovascular diseases. Mitochondrial respiratory chains are responsible for energy metabolism/ATP productionThis article discusses mitochondrial pathophysiology, reactive oxygen species, and cardiovascular diseases. Mitochondrial respiratory chains are responsible for energy metabolism/ATP production through the tricyclic antidepressant cycle, coupling of oxidative phosphorylation, and electron transfer. The mitochondrion produces reactive oxygen species as "side products" of respiration. The mitochondrial derived reactive oxygen species is involved in the pathogenesis of various clinical disorders including heart failure, hypoxia, ischemia/reperfusion injury, diabetes, neurodegenerative diseases, and the physiologic process of aging. Observational and mechanistical studies of these pathologic roles of mitochondria are discussed in depth in this article.

• Toll-like receptors 2-deficient mice are protected against postischemic coronary endothelial dysfunction.

  Authors: Julie Favre, Philippe Musette, Victorine Douin-Echinard, Karine Laude, Jean-Paul Henry, Jean-François Arnal, Christian Thuillez, Vincent Richard

  Arteriosclerosis, thrombosis, and vascular biology. 06/2007; 27(5):1064-71.

  OBJECTIVES: Toll-like receptors (TLR) 2 are expressed in cardiac and inflammatory cells, and regulate leukocyte function. Because leukocyte adhesion is a critical event in endothelial injury inducedOBJECTIVES: Toll-like receptors (TLR) 2 are expressed in cardiac and inflammatory cells, and regulate leukocyte function. Because leukocyte adhesion is a critical event in endothelial injury induced by ischemia/reperfusion (I/R), we assessed whether TLR2 were involved in I/R-induced coronary endothelial injury. METHODS AND RESULTS: Ischemia-reperfusion markedly decreased NO-mediated coronary relaxations to acetylcholine assessed ex vivo. In contrast, in TLR2 deficient mice, I/R paradoxically improved the NO-mediated responses to acetylcholine. To precise the cellular compartment expressing TLR2 which is involved in endothelial injury, we developed bone-marrow chimeric mice by transplanting TLR2-/- bone marrow to WT mice or WT bone marrow to TLR2-/- mice and submitted them to I/R 5 weeks after transplant. Both chimeric mice displayed similar protection as TLR2-/- mice against I/R-induced endothelial dysfunction, suggesting a role of TLR2 expressed on both non-bone marrow cells (in our case presumably endothelial cells and/or cardiomyocytes) and cells of bone marrow origin (presumably neutrophils). TLR2 deficiency was also associated with a smaller infarct size, and reduced reperfusion-induced production of reactive oxygen species and leukocyte infiltration. CONCLUSIONS: TLR2 contribute to coronary endothelial dysfunction after I/R, possibly through stimulation of neutrophil- (and free radical-) mediated endothelial injury.

• Role of extracellular superoxide dismutase in hypertension.

  Authors: Maria Carolina Gongora, Zhenyu Qin, Karine Laude, Ha Won Kim, Louise McCann, J Rodney Folz, Sergey Dikalov, Tohru Fukai, David G Harrison

  Hypertension. 09/2006; 48(3):473-81.

  We previously found that angiotensin II-induced hypertension increases vascular extracellular superoxide dismutase (ecSOD), and proposed that this is a compensatory mechanism that blunts theWe previously found that angiotensin II-induced hypertension increases vascular extracellular superoxide dismutase (ecSOD), and proposed that this is a compensatory mechanism that blunts the hypertensive response and preserves endothelium-dependent vasodilatation. To test this hypothesis, we studied ecSOD-deficient mice. ecSOD(-/-) and C57Blk/6 mice had similar blood pressure at baseline; however, the hypertension caused by angiotensin II was greater in ecSOD(-/-) compared with wild-type mice (168 versus 147 mm Hg, respectively; P<0.01). In keeping with this, angiotensin II increased superoxide and reduced endothelium-dependent vasodilatation in small mesenteric arterioles to a greater extent in ecSOD(-/-) than in wild-type mice. In contrast to these findings in resistance vessels, angiotensin II paradoxically improved endothelium-dependent vasodilatation, reduced intracellular and extracellular superoxide, and increased NO production in aortas of ecSOD(-/-) mice. Whereas aortic expression of endothelial NO synthase, Cu/ZnSOD, and MnSOD were not altered in ecSOD(-/-) mice, the activity of Cu/ZnSOD was increased by 80% after angiotensin II infusion. This was associated with a concomitant increase in expression of the copper chaperone for Cu/ZnSOD in the aorta but not in the mesenteric arteries. Moreover, the angiotensin II-induced increase in aortic reduced nicotinamide-adenine dinucleotide phosphate oxidase activity was diminished in ecSOD(-/-) mice as compared with controls. Thus, during angiotensin II infusion, ecSOD reduces hypertension, minimizes vascular superoxide production, and preserves endothelial function in resistance arterioles. We also identified novel compensatory mechanisms involving upregulation of copper chaperone for Cu/ZnSOD, increased Cu/ZnSOD activity, and decreased reduced nicotinamide-adenine dinucleotide phosphate oxidase activity in larger vessels. These compensatory mechanisms preserve large vessel function when ecSOD is absent in hypertension.

• Hemodynamic and biochemical adaptations to vascular smooth muscle overexpression of p22phox in mice.

  Authors: Karine Laude, Hua Cai, Bruno Fink, Nyssa Hoch, David S Weber, Louise McCann, Georg Kojda, Tohru Fukai, Harald H H W Schmidt, Sergey Dikalov, Santhini Ramasamy, Graciela Gamez, Kathy K Griendling, David G Harrison

  American journal of physiology. Heart and circulatory physiology. 02/2005; 288(1):H7-12.

  Protein levels and polymorphisms of p22(phox) have been suggested to modulate vascular NAD(P)H oxidase activity and vascular production of reactive oxygen species (ROS). We sought to determineProtein levels and polymorphisms of p22(phox) have been suggested to modulate vascular NAD(P)H oxidase activity and vascular production of reactive oxygen species (ROS). We sought to determine whether increasing p22(phox) expression would alter vascular ROS production and hemodynamics by targeting p22(phox) expression to smooth muscle in transgenic (Tg) mice. Aortas of Tg(p22smc) mice had increased p22(phox) and Nox1 protein levels and produced more superoxide and H(2)O(2). Surprisingly, endothelium-dependent relaxation and blood pressure in Tg(p22smc) mice were normal. Aortas of Tg(p22smc) mice produced twofold more nitric oxide (NO) at baseline and sevenfold more NO in response to calcium ionophore as detected by electron spin resonance. Western blot analysis revealed a twofold increase in endothelial NO synthase (eNOS) protein expression in Tg(p22smc) mice. Both eNOS expression and NO production were normalized by infusion of the glutathione peroxidase mimetic ebselen or by crossing Tg(p22smc) mice with mice overexpressing catalase. We have previously found that NO stimulates extracellular superoxide dismutase (ecSOD) expression in vascular smooth muscle. In keeping with this, aortic segments from Tg(p22smc) mice expressed twofold more ecSOD, and chronic treatment with the NOS inhibitor N(G)-nitro-L-arginine methyl ester normalized this, suggesting that NO regulates ecSOD protein expression in vivo. These data indicate that chronic oxidative stress caused by excessive H(2)O(2) production evokes a compensatory response involving increased eNOS expression and NO production. NO in turn increases ecSOD protein expression and counterbalances increased ROS production leading to the maintenance of normal vascular function and hemodynamics.

• Angiotensin II-induced hypertrophy is potentiated in mice overexpressing p22phox in vascular smooth muscle.

  Authors: David S Weber, Petra Rocic, Adamantios M Mellis, Karine Laude, Alicia N Lyle, David G Harrison, Kathy K Griendling

  American journal of physiology. Heart and circulatory physiology. 02/2005; 288(1):H37-42.

  Increased reactive oxygen species (ROS) are implicated in several vascular pathologies associated with vascular smooth muscle hypertrophy. In the current studies, we utilized transgenic (Tg) miceIncreased reactive oxygen species (ROS) are implicated in several vascular pathologies associated with vascular smooth muscle hypertrophy. In the current studies, we utilized transgenic (Tg) mice (Tg(p22smc)) that overexpress the p22(phox) subunit of NAD(P)H oxidase selectively in smooth muscle. These mice have a twofold increase in aortic p22(phox) expression and H(2)O(2) production and thus provide an excellent in vivo model in which to assess the effects of increased ROS generation on vascular smooth muscle cell (VSMC) function. We tested the hypothesis that overexpression of VSMC p22(phox) potentiates angiotensin II (ANG II)-induced vascular hypertrophy. Male Tg(p22smc) mice and negative littermate controls were infused with either ANG II or saline for 13 days. Baseline blood pressure was not different between control and Tg(p22smc) mice. ANG II significantly increased blood pressure in both groups, with this increase being slightly exacerbated in the Tg(p22smc) mice. Baseline aortic wall thickness and cross-sectional wall area were not different between control and Tg(p22smc) mice. Importantly, the ANG II-induced increase in both parameters was significantly greater in the Tg(p22smc) mice compared with control mice. To confirm that this potentiation of vascular hypertrophy was due to increased ROS levels, additional groups of mice were coinfused with ebselen. This treatment prevented the exacerbation of hypertrophy in Tg(p22smc) mice receiving ANG II. These data suggest that although increased availability of NAD(P)H oxidase-derived ROS is not a sufficient stimulus for hypertrophy, it does potentiate ANG II-induced vascular hypertrophy, making ROS an excellent target for intervention aimed at reducing medial thickening in vivo.

• ATVB in focus: redox mechanisms in blood vessels.

  Authors: Cornelius F H Mueller, Karine Laude, J Scott McNally, David G Harrison

  Arteriosclerosis, thrombosis, and vascular biology. 02/2005; 25(2):274-8.

  Reactive oxygen species have been implicated in the pathogenesis of virtually every stage of vascular lesion formation, hypertension, and other vascular diseases. We are currently gaining insightReactive oxygen species have been implicated in the pathogenesis of virtually every stage of vascular lesion formation, hypertension, and other vascular diseases. We are currently gaining insight into important sources of reactive oxygen species in the vessel wall, including the NADPH oxidases, xanthine oxidase, uncoupled nitric oxide synthase, and mitochondrial sources. Although various reactive oxygen species have pathological roles, some serve as important signaling molecules that modulate vascular tone, growth, and remodeling. In the next several months, a series of articles in Arteriosclerosis, Thrombosis, and Vascular Biology attempt to further elucidate how reactive oxygen species are produced by vascular cells and the roles of these in vascular homeostasis. This series promises to provide a valuable update on a wide variety of issues related to the biochemistry, molecular biology, and physiology of these important and fascinating molecules. Reactive oxygen species have been implicated in the pathogenesis of virtually every stage of vascular lesion formation, hypertension, and other vascular diseases. Upcoming series of articles in Arteriosclerosis, Thrombosis, and Vascular Biology help elucidate how reactive oxygen species are produced by vascular cells and their role in vascular homeostasis.

• Detection of intracellular superoxide formation in endothelial cells and intact tissues using dihydroethidium and an HPLC-based assay.

  Authors: Bruno Fink, Karine Laude, Louise McCann, Abdul Doughan, David G Harrison, Sergey Dikalov

  American journal of physiology. Cell physiology. 11/2004; 287(4):C895-902.

  Recently, it was demonstrated that superoxide oxidizes dihydroethidium to a specific fluorescent product (oxyethidium) that differs from ethidium by the presence of an additional oxygen atom in itsRecently, it was demonstrated that superoxide oxidizes dihydroethidium to a specific fluorescent product (oxyethidium) that differs from ethidium by the presence of an additional oxygen atom in its molecular structure. We have adapted this new HPLC-based assay to quantify this product as a tool to estimate intracellular superoxide in intact tissues. Ethidium and oxyethidium were separated using a C-18 column and quantified using fluorescence detection. Initial cell-free experiments with potassium superoxide and xanthine oxidase confirmed the formation of oxyethidium from dihydroethidium. The formation of oxyethidium was inhibited by superoxide dismutase but not catalase and did not occur upon the addition of H(2)O(2), peroxynitrite, or hypochlorous acid. In bovine aortic endothelial cells (BAEC) and murine aortas, the redox cycling drug menadione increased the formation of oxyethidium from dihydroethidium ninefold (0.4 nmol/mg in control vs. 3.6 nmol/mg with 20 microM menadione), and polyethylene glycol-conjugated superoxide dismutase (PEG-SOD) significantly inhibited this effect. Treatment of BAEC with angiotensin II caused a twofold increase in oxyethidium formation, and this effect also was reduced by PEG-SOD (0.5 nmol/mg). In addition, in the aortas of mice with angiotensin II-induced hypertension and DOCA-salt hypertension, the formation of oxyethidium was increased in a manner corresponding to superoxide production estimated on the basis of cytochrome c reduction. Detection of oxyethidium using HPLC represents a new, convenient, quantitative method for the detection of superoxide in intact cells and tissues.

• NO produced by endothelial NO synthase is a mediator of delayed preconditioning-induced endothelial protection.

  Authors: Karine Laude, Julie Favre, Christian Thuillez, Vincent Richard

  American journal of physiology. Heart and circulatory physiology. 07/2003; 284(6):H2053-60.

  Preconditioning with brief periods of ischemia-reperfusion (I/R) induces a delayed protection of coronary endothelial cells against reperfusion injury. We assessed the possible role of nitric oxidePreconditioning with brief periods of ischemia-reperfusion (I/R) induces a delayed protection of coronary endothelial cells against reperfusion injury. We assessed the possible role of nitric oxide (NO) produced during prolonged I/R as a mediator of this endothelial protection. Anesthetized rats were subjected to 20-min cardiac ischemia/60-min reperfusion, 24 h after sham surgery or cardiac preconditioning (1 x 2-min ischemia/5-min reperfusion and 2 x 5-min ischemia/5-min reperfusion). The nonselective NO synthase (NOS) inhibitor l-NAME, the selective inhibitors of neuronal (7-nitroindazole) or inducible (1400W) NOS, or the peroxynitrite scavenger seleno-l-methionine were administered 10 min before prolonged ischemia. Preconditioning prevented the reperfusion-induced impairment of coronary endothelium-dependent relaxations to acetylcholine (maximal relaxation: sham 77 +/- 3; I/R 44 +/- 6; PC 74 +/- 5%). This protective effect was abolished by l-NAME (41 +/- 7%), whereas 7-NI, 1400W or seleno-l-methionine had no effect. The abolition of preconditioning by l-NAME, but not by selective nNOS or iNOS inhibition, suggests that NO produced by eNOS is a mediator of delayed endothelial preconditioning.

• Heat stress increases endothelium-dependent relaxations and prevents reperfusion-induced endothelial dysfunction.

  Authors: Vincent Richard, Karine Laude, Cecile Artigues, Nathalie Kaeffer, Jean-Paul Henry, Christian Thuillez

  Clinical and experimental pharmacology & physiology. 12/2002; 29(11):956-62.

  1. Heat stress has been widely used to stimulate the expression of stress proteins and is associated with various cardiovascular changes, including anti-ischaemic effects. However, the effect of heat1. Heat stress has been widely used to stimulate the expression of stress proteins and is associated with various cardiovascular changes, including anti-ischaemic effects. However, the effect of heat stress on endothelial function is less clear. 2. Heat stress was induced in anaesthetized rats by increasing body temperature to 42 degrees C for 15 min. Twenty-four hours later, segments of rat aorta and mesenteric and coronary arteries were mounted in organ chambers. 3. Heat stress markedly increased relaxation to acetylcholine (ACh) in all three blood vessels studied, without affecting the response to the nitric oxide (NO) donor sydnonimine-1. 4. Heat stress also increased aortic relaxation to histamine and the calcium ionophore A23187. 5. In the aorta, an inhibitor of NO synthesis abolished the response to ACh in both control and heat stressed-rings, whereas a cyclo-oxygenase inhibitor had no effect. 6. Heat stress also prevented completely the impaired response to ACh in coronary arteries isolated from rats subjected to myocardial ischaemia and reperfusion. 7. Thus, heat stress increases the stimulated release of NO the rat aorta and mesenteric and coronary arteries and prevents reperfusion-induced injury at the level of the coronary endothelium.

• Peroxynitrite triggers a delayed resistance of coronary endothelial cells against ischemia-reperfusion injury.

  Authors: Karine Laude, Christian Thuillez, Vincent Richard

  American journal of physiology. Heart and circulatory physiology. 11/2002; 283(4):H1418-23.

  Experiments were designed to test whether nitric oxide (NO) and peroxynitrite trigger delayed coronary endothelial protection induced by preconditioning (PC) in rats. Prolonged ischemia reperfusionExperiments were designed to test whether nitric oxide (NO) and peroxynitrite trigger delayed coronary endothelial protection induced by preconditioning (PC) in rats. Prolonged ischemia reperfusion markedly reduced the response of isolated coronary arteries to acetylcholine, and this was prevented by PC performed 24 h earlier. The NO synthase (NOS) inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME) administered during PC abolished its delayed endothelial protective effect, whereas the inducible NOS inhibitor N-(3(aminomethyl)benzyl)acetaminide had no effect. Delayed endothelial PC was also abolished by the peroxynitrite scavengers selenomethionine or uric acid given during PC. In parallel, the NO/peroxynitrite donor S-morpholinosydnonimine and authentic peroxynitrite, administered 24 h before prolonged ischemia-reperfusion mimicked endothelial PC, whereas the NO donor S-nitroso-N-acetylpencillamine had no effect. This suggests that peroxynitrite is an essential trigger of the delayed coronary endothelial protection induced by PC in rat hearts.

• Endothelial protective effects of preconditioning.

  Authors: Karine Laude, Philippe Beauchamp, Christian Thuillez, Vincent Richard

  Cardiovascular research. 09/2002; 55(3):466-73.

  The consequences of cardiac ischemia-reperfusion are not limited to myocytes but also extend to the coronary endothelium, where they are characterized by decreased nitric oxide (NO)-dependentThe consequences of cardiac ischemia-reperfusion are not limited to myocytes but also extend to the coronary endothelium, where they are characterized by decreased nitric oxide (NO)-dependent relaxations. Given the essential role of the endothelium and NO in the regulation of vascular tone as well as platelet and leukocyte function, protection of coronary endothelial cells is an important therapeutic target. In this context, several studies have shown that both early and delayed preconditioning may prevent endothelial dysfunction after index ischemia-reperfusion. This endothelial protection most likely results from the inhibitory effects of preconditioning on expression of endothelial adhesion molecules, resulting in reduced neutrophil-endothelial interactions. The mechanisms of early endothelial preconditioning resemble those described at the level of the myocytes, and may involve mediators such as adenosine, bradykinin, NO and free radicals, together with activation of protein kinase C and opening of ATP-sensitive potassium channels. With regard to delayed preconditioning, recent studies have shown that both NO and free radicals are involved as triggers of this second window of endothelial protection. The complex interactions between these two radical species ultimately lead to a delayed increase in NO production, most likely responsible for the decreased adhesion of neutrophils to endothelial cells. Further identification of the triggers and mediators of this endothelial protection will allow the development of new therapeutic agents targeting both the myocardium and the coronary vasculature.