Rho kinase inhibition improves endothelial function in human subjects with coronary artery disease

Abstract

Investigations from basic biology suggest that activation of the Rho/Rho kinase pathway reduces the bioavailability of nitric oxide (NO) and thereby promotes atherosclerosis and its clinical complications. Yet, little information is available about the relationship of the Rho/Rho kinase pathway to NO bioavailability in humans with atherosclerosis. Accordingly, we determined whether inhibition of Rho kinase augments NO bioavailability and improves endothelial function in human subjects with coronary artery disease (CAD). Thirteen CAD subjects and 16 age- and sex-matched healthy controls were randomly assigned to receive the Rho kinase inhibitor, fasudil, or placebo for 1 month each in a double-blind crossover trial. Flow-mediated, endothelium-dependent and nitroglycerin-induced, endothelium-independent vasodilation were assessed by brachial artery ultrasonography. Rho kinase activity was measured in peripheral leukocytes. Fasudil increased endothelium-dependent vasodilation in CAD subjects from 9.4+/-1.9% to 13.4+/-1.9% (P=0.001) but not in healthy controls (from 11.3+/-1.4% to 7.7+/-1.1%; P=0.07). Endothelium-independent vasodilation was not affected by fasudil in either CAD or healthy subjects. Fasudil reduced Rho kinase activity by 59+/-18% in CAD subjects (P=0.001) but not in healthy subjects (by 3+/-6%; P=0.60). The change in endothelium-dependent vasodilation achieved with fasudil relative to placebo was inversely proportional to Rho kinase inhibition (ie, greater Rho kinase inhibition was associated with larger improvement in endothelium-dependent vasodilation) (r=-0.48; P=0.01). These findings suggest that Rho/Rho kinase activation promotes endothelial dysfunction in humans with atherosclerosis. Inhibition of the Rho/Rho kinase pathway should provide a useful strategy to restore NO bioavailability in humans with atherosclerosis.

Figures

Figure 1

Study protocol.

Figure 2

Effect of fasudil on flow-mediated vasodilation. Results are expressed as mean±SE. The percentage increase in brachial artery diameter 1 minute after cuff release compared with the baseline is illustrated. Fasudil increased flow-mediated, endothelium-dependent vasodilation significantly in the CAD subjects (P=0.001) but not in healthy controls (P=0.07).

Figure 3

Effect of fasudil on nitroglycerin-mediated vasodilation. Results are expressed as mean±SE. The percentage increase in brachial artery diameter 3 minutes after sublingual nitroglycerin administration compared with baseline is illustrated. Fasudil did not significantly alter nitroglycerin-mediated, endothelium-independent vasodilation in either CAD or healthy subjects

Figure 4

Correlation of Rho kinase inhibition with fasudil and change in endothelium-dependent vasodilation. For the entire cohort of 28 patients, the change in flow-mediated, endothelium-dependent vasodilation after fasudil relative to placebo was inversely proportional to the extent of Rho kinase inhibition with fasudil (r=−0.48, P=0.01). Squares represent CAD and triangles represent healthy subjects, respectively.