Julian D Widder

Publications of Julian D Widder

• Conditional overexpression of neuronal nitric oxide synthase is cardioprotective in ischemia/reperfusion.

  Authors: Natalie Burkard, Tatjana Williams, Martin Czolbe, Nadja Blömer, Franziska Panther, Martin Link, Daniela Fraccarollo, Julian D Widder, Kai Hu, Hong Han, Ulrich Hofmann, Stefan Frantz, Peter Nordbeck, Jan Bulla, Kai Schuh, Oliver Ritter

  Circulation. 10/2010; 122(16):1588-603.

  We previously demonstrated that conditional overexpression of neuronal nitric oxide synthase (nNOS) inhibited L-type Ca2+ channels and decreased myocardial contractility. However, nNOS has multipleWe previously demonstrated that conditional overexpression of neuronal nitric oxide synthase (nNOS) inhibited L-type Ca2+ channels and decreased myocardial contractility. However, nNOS has multiple targets within the cardiac myocyte. We now hypothesize that nNOS overexpression is cardioprotective after ischemia/reperfusion because of inhibition of mitochondrial function and a reduction in reactive oxygen species generation. Ischemia/reperfusion injury in wild-type mice resulted in nNOS accumulation in the mitochondria. Similarly, transgenic nNOS overexpression caused nNOS abundance in mitochondria. nNOS translocation into the mitochondria was dependent on heat shock protein 90. Ischemia/reperfusion experiments in isolated hearts showed a cardioprotective effect of nNOS overexpression. Infarct size in vivo was also significantly reduced. nNOS overexpression also caused a significant increase in mitochondrial nitrite levels accompanied by a decrease of cytochrome c oxidase activity. Accordingly, O(2) consumption in isolated heart muscle strips was decreased in nNOS-overexpressing nNOS(+)/αMHC-tTA(+) mice already under resting conditions. Additionally, we found that the reactive oxygen species concentration was significantly decreased in hearts of nNOS-overexpressing nNOS(+)/αMHC-tTA(+) mice compared with noninduced nNOS(+)/αMHC-tTA(+) animals. We demonstrated that conditional transgenic overexpression of nNOS resulted in myocardial protection after ischemia/reperfusion injury. Besides a reduction in reactive oxygen species generation, this might be caused by nitrite-mediated inhibition of mitochondrial function, which reduced myocardial oxygen consumption already under baseline conditions.

• Impairment of endothelial progenitor cell function and vascularization capacity by aldosterone in mice and humans.

  Authors: Thomas Thum, Kerstin Schmitter, Felix Fleissner, Volker Wiebking, Bernd Dietrich, Julian D Widder, Virginija Jazbutyte, Stefanie Hahner, Georg Ertl, Johann Bauersachs

  European heart journal. 10/2010; 32(10):1275-86.

  Hyperaldosteronism is associated with vascular injury and increased cardiovascular events. Bone marrow-derived endothelial progenitor cells (EPCs) play an important role in endothelial repair andHyperaldosteronism is associated with vascular injury and increased cardiovascular events. Bone marrow-derived endothelial progenitor cells (EPCs) play an important role in endothelial repair and vascular homeostasis. We hypothesized that hyperaldosteronism impairs EPC function and vascularization capacity in mice and humans. We characterized the effects of aldosterone and mineralocorticoid receptor (MR) blockade on EPC number and function as well as vascularization capacity and endothelial function. Treatment of human EPC with aldosterone induced translocation of the MR and impaired multiple cellular functions of EPC, such as differentiation, migration, and proliferation in vitro. Impaired EPC function was rescued by pharmacological blockade or genetic ablation of the MR. Aldosterone protein kinase A (PKA) dependently increased reactive oxygen species formation in EPC. Aldosterone infusion in mice impaired EPC function, EPC homing to vascular structures and vascularization capacity in a MR-dependent but blood pressure-independent manner. Endothelial progenitor cells from patients with primary hyperaldosteronism compared with controls of similar age displayed reduced migratory potential. Impaired EPC function was associated with endothelial dysfunction. MR blockade in patients with hyperaldosteronism improved EPC function and arterial stiffness. Endothelial progenitor cells express a MR that mediates functional impairment by PKA-dependent increase of reactive oxygen species. Normalization of EPC function may represent a novel mechanism contributing to the beneficial effects of MR blockade in cardiovascular disease prevention and treatment.

• Increased cytochrome P4502E1 expression and altered hydroxyeicosatetraenoic acid formation mediate diabetic vascular dysfunction: rescue by guanylyl-cyclase activation.

  Authors: Andreas Schäfer, Paolo Galuppo, Daniela Fraccarollo, Christian Vogt, Julian D Widder, Julia Pfrang, Piet Tas, Eduardo Barbosa-Sicard, Hartmut Ruetten, Georg Ertl, Ingrid Fleming, Johann Bauersachs

  Diabetes. 08/2010; 59(8):2001-9.

  We investigated the mechanisms underlying vascular endothelial and contractile dysfunction in diabetes as well as the effect of HMR1766, a novel nitric oxide (NO)-independent activator of solubleWe investigated the mechanisms underlying vascular endothelial and contractile dysfunction in diabetes as well as the effect of HMR1766, a novel nitric oxide (NO)-independent activator of soluble guanylyl cyclase (sGC). Two weeks after induction of diabetes by streptozotocin, Wistar rats received either placebo or HMR1766 (10 mg/kg twice daily) for another 2 weeks; thereafter, vascular function was assessed. Endothelial function and contractile responses were significantly impaired, while vascular superoxide formation was increased in the aortae from diabetic versus healthy control rats. Using RNA microarrays, cytochrome P4502E1 (CYP2E1) was identified as the highest upregulated gene in diabetic aorta. CYP2E1 protein was significantly increased (16-fold) by diabetes, leading to a reduction in levels of the potent vasoconstrictor 20-hydroxy-eicosatetraenoic acid (20-HETE). Induction of CYP2E1 expression in healthy rats using isoniazide mimicked the diabetic noncontractile vascular response while preincubation of aortae from STZ-diabetic rats in vitro with 20-HETE rescued contractile function. Chronic treatment with the sGC activator HMR1766 improved NO sensitivity and endothelial function, reduced CYP2E1 expression and superoxide formation, enhanced 20-HETE levels, and reversed the contractile deficit observed in the diabetic rats that received placebo. Upregulation of CYP2E1 is essentially involved in diabetic vascular dysfunction. Chronic treatment with the sGC activator HMR1766 reduced oxidative stress, decreased CYP2E1 levels, and normalized vasomotor function in diabetic rats.

• Reductive stress: linking heat shock protein 27, glutathione, and cardiomyopathy?

  Authors: Johann Bauersachs, Julian D Widder

  Hypertension. 06/2010; 55(6):1299-300.

• Exercise, eNOS and the heart after myocardial infarction.

  Authors: Julian D Widder, Georg Ertl

  Journal of molecular and cellular cardiology. 02/2010; 48(6):1029-30.

• Loss of creatine in heart failure: A loss-win situation?

  Authors: Julian D Widder, Georg Ertl

  Journal of molecular and cellular cardiology. 12/2009;

• Attenuation of Angiotensin II-Induced Vascular Dysfunction and Hypertension by Overexpression of Thioredoxin 2.

  Authors: Julian D Widder, Daniela Fraccarollo, Paolo Galuppo, Jason M Hansen, Dean P Jones, Georg Ertl, Johann Bauersachs

  Hypertension. 06/2009;

  Reactive oxygen species increase in the cardiovascular system during hypertension and in response to angiotensin II. Because mitochondria contribute to reactive oxygen species generation, we soughtReactive oxygen species increase in the cardiovascular system during hypertension and in response to angiotensin II. Because mitochondria contribute to reactive oxygen species generation, we sought to investigate the role of thioredoxin 2, a mitochondria-specific antioxidant enzyme. Mice were created with overexpression of human thioredoxin 2 (Tg(hTrx2) mice) and backcrossed to C57BL/6J mice for >/=6 generations. Twelve-week-old male Tg(hTrx2) or littermate wild-type mice were made hypertensive by infusion of angiotensin II (400 ng/kg per minute) for 14 days using osmotic minipumps. Systolic arterial blood pressure was not different between Tg(hTrx2) and wild-type animals under baseline conditions (101+/-1 respective 102+/-1 mm Hg). The angiotensin II-induced hypertension in wild-type mice (145+/-2 mm Hg) was significantly attenuated in Tg(hTrx2) mice (124+/-1 mm Hg; P<0.001). Aortic endothelium-dependent relaxation was significantly reduced in wild-type mice after angiotensin II infusion but nearly unchanged in transgenic mice. Elevated vascular superoxide and hydrogen peroxide levels, as well as expression of NADPH oxidase subunits in response to angiotensin II infusion, were significantly attenuated in Tg(hTrx2) mice. Mitochondrial superoxide anion levels were augmented after angiotensin II infusion in wild-type mice, and this was blunted in Tg(hTrx2) mice. Angiotensin II infusion significantly increased myocardial superoxide formation, heart weight, and cardiomyocyte size in wild-type but not in Tg(hTrx2) mice. These data indicate a major role for mitochondrial thioredoxin 2 in the development of cardiovascular alterations and hypertension during chronic angiotensin II infusion. Thioredoxin 2 may represent an important therapeutic target for the prevention and treatment of hypertension and oxidative stress.

• Tetrahydrobiopterin, Endothelial Nitric Oxide Synthase, and Mitochondrial Function in the Heart.

  Authors: Johann Bauersachs, Julian D Widder

  Hypertension. 05/2009;

• Improvement in left ventricular remodeling by the endothelial nitric oxide synthase enhancer AVE9488 after experimental myocardial infarction.

  Authors: Daniela Fraccarollo, Julian D Widder, Paolo Galuppo, Thomas Thum, Dimitrios Tsikas, Michael Hoffmann, Hartmut Ruetten, Georg Ertl, Johann Bauersachs

  Circulation. 09/2008; 118(8):818-27.

  BACKGROUND: Reduced endothelial nitric oxide (NO) bioavailability contributes to the progression of heart failure. In this study, we investigated whether the transcription enhancer of endothelial NOBACKGROUND: Reduced endothelial nitric oxide (NO) bioavailability contributes to the progression of heart failure. In this study, we investigated whether the transcription enhancer of endothelial NO synthase (eNOS) AVE9488 improves cardiac remodeling and heart failure after experimental myocardial infarction (MI). METHODS AND RESULTS: Starting 7 days after coronary artery ligation, rats with MI were treated with placebo or AVE9488 (25 ppm) as a dietary supplement for 9 weeks. AVE9488 therapy versus placebo substantially improved left ventricular (LV) function, reduced LV filling pressure, and prevented the rightward shift of the pressure-volume curve. AVE9488 also attenuated the extent of pulmonary edema, reduced LV fibrosis and myocyte cross-sectional area, and prevented the increases in LV gene expression of atrial natriuretic factor, brain natriuretic peptide, and endothelin-1. eNOS protein levels and calcium-dependent NOS activity were decreased in the surviving LV myocardium from placebo MI rats and normalized by AVE9488. The beneficial effects of AVE9488 on LV dysfunction and remodeling after MI were abrogated in eNOS-deficient mice. Aortic eNOS protein expression and endothelium-dependent NO-mediated vasorelaxation were significantly enhanced by AVE9488 treatment after infarction, whereas increased vascular superoxide anion formation was reduced. Moreover, AVE9488 prevented the marked depression of circulating endothelial progenitor cell levels in rats with heart failure after MI. CONCLUSIONS: Long-term treatment with the eNOS enhancer AVE9488 improved LV remodeling and contractile dysfunction after MI. Molecular alterations, circulating endothelial progenitor cell levels, and endothelial vasomotor dysfunction were improved by AVE9488. Pharmacological interventions designed to increase eNOS-derived NO constitute a promising therapeutic approach for the amelioration of postinfarction ventricular remodeling and heart failure.

• Multidrug resistance protein-1 affects oxidative stress, endothelial dysfunction, and atherogenesis via leukotriene C4 export.

  Authors: Cornelius F H Mueller, Kerstin Wassmann, Julian D Widder, Sven Wassmann, Chia Hui Chen, Barbara Keuler, Alexey Kudin, Wolfram S Kunz, Georg Nickenig

  Circulation. 07/2008; 117(22):2912-8.

  BACKGROUND: We recently showed that the multidrug resistance related protein-1 (MRP1) is important for the management of oxidative stress in vascular cells. However, the underlying mechanism and theBACKGROUND: We recently showed that the multidrug resistance related protein-1 (MRP1) is important for the management of oxidative stress in vascular cells. However, the underlying mechanism and the in vivo relevance of these findings remain elusive. We hypothesize that inside-outside transport of leukotriene C(4) (LTC(4)) via MRP1 is a substantial proatherogenic mechanism in the vasculature. To test this hypothesis, we investigated the effects of MRP1 inhibition and LTC(4) receptor blockade (Cys-LT1 receptor) in vitro and in vivo. METHODS AND RESULTS: MRP1 is expressed abundantly in vascular smooth muscle cells (VSMCs). Pharmacological inhibition of MRP1 via MK571 reduces angiotensin II-induced reactive oxygen species release by 59% (L012 fluorescence) in VSMCs. The release of reactive oxygen species after angiotensin II stimulation also is inhibited by blockade of the Cys-LT1 receptor with montelukast. Incubation of VSMCs with recombined LTC(4) causes enhanced rates of reactive oxygen species and proliferation in wild-type and MRP1(-/-) VSMCs. Accordingly, the LTC(4) release in the cell culture supernatant of MRP1(-/-) VSMCs is significantly decreased compared with wild-type cells. To extend our observations to the in vivo situation, atherosclerosis-prone apolipoprotein E-deficient mice on a high-cholesterol diet were treated with placebo, the MRP1 inhibitor MK571, or the Cys-LT1 receptor inhibitor montelukast for 6 weeks. Treatment with MK571 or montelukast reduced vascular reactive oxygen species production, significantly improved endothelial function, and ameliorated atherosclerotic plaque generation by 52% and 61%, respectively. CONCLUSIONS: These findings indicate that MRP1 and LTC(4) exert proatherosclerotic effects and that both MRP1 and LTC(4) are potentially promising targets for atheroprotective therapy.

• Regulation of tetrahydrobiopterin biosynthesis by shear stress.

  Authors: Julian D Widder, Wei Chen, Li Li, Sergey Dikalov, Beat Thöny, Kazuyuki Hatakeyama, David G Harrison

  Circulation research. 11/2007; 101(8):830-8.

  An essential cofactor for the endothelial NO synthase is tetrahydrobiopterin (H4B). In the present study, we show that in human endothelial cells, laminar shear stress dramatically increases H4BAn essential cofactor for the endothelial NO synthase is tetrahydrobiopterin (H4B). In the present study, we show that in human endothelial cells, laminar shear stress dramatically increases H4B levels and enzymatic activity of GTP cyclohydrolase (GTPCH)-1, the first step of H4B biosynthesis. In contrast, protein levels of GTPCH-1 were not affected by shear. Shear did not change protein expression or activity of the downstream enzymes 6-pyruvoyl-tetrahydropterin synthase and sepiapterin reductase and decreased protein levels of the salvage enzyme dihydrofolate reductase. Oscillatory shear only modestly affected H4B levels and GPTCH-1 activity. We also demonstrate that laminar, but not oscillatory shear stress, stimulates phosphorylation of GTPCH-1 on serine 81 and that this is mediated by the alpha prime (alpha') subunit of casein kinase 2. The increase in H4B caused by shear is essential in allowing proper function of endothelial NO synthase because GPTCH-1 blockade with 2,4-diamino-6-hydroxypyrimidine during shear inhibited dimer formation of endothelial NO synthase, increased endothelial cell superoxide production, and prevented the increase in NO production caused by shear. Thus, shear stress not only increases endothelial NO synthase levels but also stimulates production of H4B by markedly enhancing GTPCH-1 activity via casein kinase 2-dependent phosphorylation on serine 81. These findings illustrate a new function of casein kinase 2 in the endothelium and provide insight into regulation of GTPCH-1 activity.

• Role of the multidrug resistance protein-1 in hypertension and vascular dysfunction caused by angiotensin II.

  Authors: Julian D Widder, Tomasz J Guzik, Cornelius F H Mueller, Roza E Clempus, Harald H H W Schmidt, Sergey I Dikalov, Kathy K Griendling, Dean P Jones, David G Harrison

  Arteriosclerosis, thrombosis, and vascular biology. 05/2007; 27(4):762-8.

  OBJECTIVE: Human endothelial cells use the multidrug resistance protein-1 (MRP1) to export glutathione disulfide (GSSG). This can promotes thiol loss during states of increased glutathione oxidation.OBJECTIVE: Human endothelial cells use the multidrug resistance protein-1 (MRP1) to export glutathione disulfide (GSSG). This can promotes thiol loss during states of increased glutathione oxidation. We investigated how MRP1 modulates blood pressure and vascular function during angiotensin II-induced hypertension. METHODS AND RESULTS: Angiotensin II-induced hypertension altered vascular glutathione flux by increasing GSSG export and decreasing vascular levels of glutathione in wild-type (FVB) but not in MRP1-/- mice. Aortic endothelium-dependent vasodilatation was reduced in FVB after angiotensin II infusion, but unchanged in MRP1-/- mice. Aortic superoxide (O2*-) production and expression of several NADPH oxidase subunits were increased by angiotensin II in FVB. These effects were markedly blunted in MRP1-/- vessels. The increase in O2*- production in FVB vessels caused by angiotensin II was largely inhibited by L-NAME, suggesting eNOS uncoupling. Accordingly, aortic tetrahydrobiopterin and levels of NO were decreased by angiotensin II in FVB but were unchanged in MRP1-/-. Finally, the hypertension caused by angiotensin II was markedly blunted in MRP1-/- mice (137+/-4 versus 158+/-6 mm Hg). CONCLUSION: MRP1 plays a crucial role in the genesis of multiple vascular abnormalities that accompany hypertension and its presence is essential for the hypertensive response to angiotensin II.

• Endothelial nitric oxide synthase uncoupling impairs endothelial progenitor cell mobilization and function in diabetes.

  Authors: Thomas Thum, Daniela Fraccarollo, Maximilian Schultheiss, Sabrina Froese, Paolo Galuppo, Julian D Widder, Dimitrios Tsikas, Georg Ertl, Johann Bauersachs

  Diabetes. 04/2007; 56(3):666-74.

  Uncoupling of the endothelial nitric oxide synthase (eNOS) resulting in superoxide anion (O(2)(-)) formation instead of nitric oxide (NO) causes diabetic endothelial dysfunction. eNOS regulatesUncoupling of the endothelial nitric oxide synthase (eNOS) resulting in superoxide anion (O(2)(-)) formation instead of nitric oxide (NO) causes diabetic endothelial dysfunction. eNOS regulates mobilization and function of endothelial progenitor cells (EPCs), key regulators of vascular repair. We postulate a role of eNOS uncoupling for reduced number and function of EPC in diabetes. EPC levels in diabetic patients were significantly reduced compared with those of control subjects. EPCs from diabetic patients produced excessive O(2)(-) and showed impaired migratory capacity compared with nondiabetic control subjects. NOS inhibition with N(G)-nitro-l-arginine attenuated O(2)(-) production and normalized functional capacity of EPCs from diabetic patients. Glucose-mediated EPC dysfunction was protein kinase C dependent, associated with reduced intracellular BH(4) (tetrahydrobiopterin) concentrations, and reversible after exogenous BH(4) treatment. Activation of NADPH oxidases played an additional but minor role in glucose-mediated EPC dysfunction. In rats with streptozotocin-induced diabetes, circulating EPCs were reduced to 39 +/- 5% of controls and associated with uncoupled eNOS in bone marrow. Our results identify uncoupling of eNOS in diabetic bone marrow, glucose-treated EPCs, and EPCs from diabetic patients resulting in eNOS-mediated O(2)(-) production. Subsequent reduction of EPC levels and impairment of EPC function likely contributes to the pathogenesis of vascular disease in diabetes.

• Early determinants of H2O2-induced endothelial dysfunction.

  Authors: Beth M Boulden, Julian D Widder, Jon C Allen, Debra A Smith, Ruaa N Al-Baldawi, David G Harrison, Sergey I Dikalov, Hanjoong Jo, Samuel C Dudley

  Free radical biology & medicine. 09/2006; 41(5):810-7.

  Reactive oxygen species (ROS) can stimulate nitric oxide (NO(*)) production from the endothelium by transient activation of endothelial nitric oxide synthase (eNOS). With continued or repeatedReactive oxygen species (ROS) can stimulate nitric oxide (NO(*)) production from the endothelium by transient activation of endothelial nitric oxide synthase (eNOS). With continued or repeated exposure, NO(*) production is reduced, however. We investigated the early determinants of this decrease in NO(*) production. Following an initial H(2)O(2) exposure, endothelial cells responded by increasing NO(*) production measured electrochemically. NO(*) concentrations peaked by 10 min with a slow reduction over 30 min. The decrease in NO(*) at 30 min was associated with a 2.7-fold increase in O(2)(*-) production (p < 0.05) and a 14-fold reduction of the eNOS cofactor, tetrahydrobiopterin (BH(4), p < 0.05). Used as a probe for endothelial dysfunction, the integrated NO(*) production over 30 min upon repeated H(2)O(2) exposure was attenuated by 2.1-fold (p = 0.03). Endothelial dysfunction could be prevented by BH(4) cofactor supplementation, by scavenging O(2)(*-) or peroxynitrite (ONOO(-)), or by inhibiting the NADPH oxidase. Hydroxyl radical (()OH) scavenging did not have an effect. In summary, early H(2)O(2)-induced endothelial dysfunction was associated with a decreased BH(4) level and increased O(2)(*-) production. Dysfunction required O(2)(*-), ONOO(-), or a functional NADPH oxidase. Repeated activation of the NADPH oxidase by ROS may act as a feed forward system to promote endothelial dysfunction.

• Can vitamin E prevent cardiovascular events and cancer?

  Authors: Julian D Widder, David G Harrison

  Nature clinical practice. Cardiovascular medicine. 11/2005; 2(10):510-1.

• The role of the multidrug resistance protein-1 in modulation of endothelial cell oxidative stress.

  Authors: Cornelius F H Mueller, Julian D Widder, Joseph S McNally, Louise McCann, Dean P Jones, David G Harrison

  Circulation research. 10/2005; 97(7):637-44.

  Glutathione (GSH) is the major source of intracellular sulfhydryl groups. Oxidized GSH (GSSG) can be recycled to GSH by the GSH reductase or exported from the cell. The mechanism by which GSSG isGlutathione (GSH) is the major source of intracellular sulfhydryl groups. Oxidized GSH (GSSG) can be recycled to GSH by the GSH reductase or exported from the cell. The mechanism by which GSSG is exported and the consequence of its export from endothelial cells has not been defined previously. We found that human endothelial cells express the multidrug resistance protein-1 (MRP1) and use this as their major exporter of GSSG. Oscillatory shear stress, which is known to stimulate endothelial cell production of reactive oxygen species, decreased intracellular GSH. In contrast, laminar shear significantly increased intracellular GSH. Oscillatory shear also caused a robust export of GSSG that was prevented by the MRP1 inhibitor MK571 and by MRP1 small interfering RNA. MRP1 inhibition prevented the decline in intracellular GSH, preserved the intracellular GSH Nernst potential, and reduced apoptosis caused by oscillatory shear. In aortas of hypertensive mice, endothelial disulfide export was doubled, and this was prevented by MK571 and was not observed in aortas of hypertensive MRP1-/- mice. Further, the altered endothelium-dependent vasodilatation caused by hypertension was ameliorated in MRP1-/- mice. GSSG export by MRP1 leads to a perturbation of endothelial redox state and ultimately endothelial cell apoptosis. Endothelial MRP1 may provide a novel therapeutic target for prevention of vascular disease.

• Endothelial dysfunction in heart failure.

  Authors: Johann Bauersachs, Julian D Widder

  Pharmacological reports : PR. 60(1):119-26.

  Endothelial dysfunction crucially contributes to the development of impaired coronary and systemic perfusion as well as reduced exercise capacity in patients with congestive heart failure, withEndothelial dysfunction crucially contributes to the development of impaired coronary and systemic perfusion as well as reduced exercise capacity in patients with congestive heart failure, with fundamental impact on morbidity and mortality. Reduced bioavailability of nitric oxide (NO) and abundant formation of reactive oxygen species (ROS) within the vascular wall are the key determinants in endothelial dysfunction. The disbalance between NO and ROS mainly results from neurohumoral activation associated with heart failure. As endothelial derived NO is a major endogenous modulator of platelet function, reduced intravascular bioactivity of NO contributes to platelet activation, adhesion and thromboembolic events in heart failure. Treatment with angiotensin converting enzyme (ACE) inhibitors, angiotensin and aldosterone antagonists, and statins beneficially modulates endothelial dysfunction in heart failure. All these therapies increase NO bioactivity by either modulation of ROS generation, thereby preventing the interaction of superoxide anions with NO, and/or increasing endothelial NO synthase (eNOS) expression/activity. AVE9488, a novel eNOS transcription enhancer, attenuates cardiac remodeling and endothelial dysfunction in rats after large myocardial infarction. Endothelial progenitor cell (EPC) levels and their mobilization are regulated by eNOS. After myocardial infarction in rats, EPC levels and formation of endothelial colony forming units are markedly reduced. AVE 9488, ACE or HMG-CoA reductase inhibition result in significant increases in EPC levels, and beneficial effects on bone marrow molecular alterations after myocardial infarction.