Université de Fribourg

Regulation of vascular endothelial function by RhoA/Rho-kinase pathway : implications for cardiovascular diseases

Viswambharan, Hema ; Yang, Zhihong (Dir.) ; Hayoz, Daniel (Codir.)

Thèse de doctorat : Université de Fribourg, 2005 ; Nr. 1475.

The vascular endothelium plays an important role in the maintenance of normal cardiovascular functions. It prevents smooth muscle contraction, inhibits smooth muscle cell proliferation and/or migration and exerts anti-thrombotic effects. One of the most important factors derived from endothelial cells is nitric oxide (NO) which is produced via activation of endothelial NO synthase (eNOS). eNOS...

Université de Fribourg

Endothelial-specific deletion of Connexin40 promotes atherosclerosis by increasing CD73-dependent leukocyte adhesion

Chadjichristos, C.E. ; Scheckenbach, K.E.L. ; Veen, T.A.B. van ; Richani Sarieddine, M.Z. ; Wit, C. de ; Yang, Zhihong ; Roth, I. ; Bacchetta, M. ; Viswambharan, Hema ; Foglia, B. ; Dudez, T. ; Kempen, M.J.A. van ; Coenjaerts, F.E.J. ; Miquerol, L. ; Deutsch, U. ; Jongsma, H.J. ; Chanson, M. ; Kwak, B.R.

In: Circulation, 2010, vol. 121, p. 123-131

Background— Endothelial dysfunction is the initiating event of atherosclerosis. The expression of connexin40 (Cx40), an endothelial gap junction protein, is decreased during atherogenesis. In the present report, we sought to determine whether Cx40 contributes to the development of the disease.Methods and Results— Mice with ubiquitous deletion of Cx40 are hypertensive, a risk factor for...

Université de Fribourg

Endothelial nitric oxide synthase gene transfer inhibits human smooth muscle cell migration via inhibition of Rho A

Largiadèr, Thomas ; Eto, Masato ; Payeli, Sravan K. ; Greutert, Helen ; Viswambharan, Hema ; Lachat, Mario ; Zünd, Gregor ; Yang, Zhihong ; Tanner, Felix C. ; Lüscher, Thomas F.

In: Journal of Cardiovascular Pharmacology, 2008, vol. 52, no. 4, p. 369-374

Smooth muscle cell (SMC) migration contributes to vascular remodeling. Nitric oxide (NO) produced via endothelial NO synthase (eNOS) inhibits SMC migration. This study analyzes signal transduction mechanisms of SMC migration targeted by NO. SMCs were cultured from human saphenous veins, and cell migration was studied using Boyden chambers. PDGF-BB (0.1 to 10 ng/ml) stimulated SMC migration in a...

Université de Fribourg

Sirolimus increases tissue factor expression but not activity in cultured human vascular smooth muscle cells

Zhu, Shengsi ; Viswambharan, Hema ; Gajanayake, Thusitha ; Ming, Xiu-Fen ; Yang, Zhihong

In: BMC Cardiovascular Disorders, 2007, vol. 5, p. 22

Background Sirolimus-eluting stents (CYPHER stents) demonstrated remarkable efficacy in reducing restenosis rates in patients with coronary artery disease. There is a concern of sub-acute and late stent thrombosis. Tissue factor (TF) is critical in thrombosis. This study investigated the effect of sirolimus on TF expression and activity in cultured human vascular smooth muscle cells...

Université de Fribourg

Mutation of the circadian clock gene Per2 alters vascular endothelial function

Viswambharan, Hema ; Carvas, João Miguel ; Antic, Vladan ; Marecic, Ana ; Jud, Corinne ; Zaugg, Christian E. ; Ming, Xiu-Fen ; Montani, Jean-Pierre ; Albrecht, Urs ; Yang, Zhihong

In: Circulation, 2007, vol. 115, p. 2188-2195

Background— The circadian clock regulates biological processes including cardiovascular function and metabolism. In the present study, we investigated the role of the circadian clock gene Period2 (Per2) in endothelial function in a mouse model. Methods and Results— Compared with the wild-type littermates, mice with Per2 mutation exhibited impaired...

Université de Fribourg

Endothelial nitric oxide synthase gene transfer restores endothelium–dependent relaxations and attenuates lesion formation in carotid arteries in apolipoprotein E–deficient mice

Mujynya-Ludunge, Kathi ; Viswambharan, Hema ; Driscoll, Robert ; Ming, Xiu-Fen ; Segesser, Ludwig K. von ; Kappenberger, Lukas ; Yang, Zhihong ; Vassalli, Giuseppe

In: Basic Research in Cardiology, 2005, vol. 100(2), p. 102

Nitric oxide (NO) and monocyte chemoattractant protein–1 (MCP-1) exert partly opposing effects in vascular biology. NO plays pleiotropic vasoprotective roles including vasodilation and inhibition of platelet aggregation, smooth muscle cell proliferation, and endothelial monocyte adhesion, the last effect being mediated by MCP–1 downregulation. Early stages of arteriosclerosis are associated...

Université de Fribourg

Thrombin Stimulates Human Endothelial Arginase Enzymatic Activity via RhoA/ROCK Pathway

Ming, Xiu-Fen ; Barandier, Christine ; Viswambharan, Hema ; Kwak, Brenda R. ; Mach, François ; Mazzolai, Lucia ; Hayoz, Daniel ; Ruffieux, Jean ; Rusconi, Sandro ; Montani, Jean-Pierre ; Yang, Zhihong

In: Circulation, 2004, vol. 110, p. 3708-3714

Background— Arginase competes with endothelial nitric oxide synthase (eNOS) for the substrate L-arginine and decreases NO production. This study investigated regulatory mechanisms of arginase activity in endothelial cells and its role in atherosclerosis. Methods and Results— In human endothelial cells isolated from umbilical veins, thrombin concentration- and time-dependently stimulated...