High Blood Pressure May Be Cause Of Endothelial Dysfunction

Transient increases in intravascular pressure significantly depress endothelium-dependent vasodilation in human resistance arteries, a study has found.

This suggests elevated blood pressure may cause endothelial dysfunction in humans and, in turn, has implications for the pathophysiology of endothelial dysfunction in hypertension, the authors point out.

Although hypertension is linked with decreased endothelium-dependent vasodilation, until now it has been unknown whether endothelial dysfunction is a cause or a consequence of elevated blood pressure.

To determine whether hypertension can directly induce endothelial dysfunction, this study investigated the effect of intra-arterial pressure increases on endothelium-dependent vasodilation of the human microvasculature.

Participants were eight men and four women, with an average of 46 years of age, who were healthy and normotensive. Their small arteries were isolated from gluteal fat biopsies and cannulated and perfused in chambers oxygenated at 37 degrees C.

Endothelium-dependent and -independent responses to acetylcholine (Ach; 10-9 to 10-4 mol/L) and sodium nitroprusside (SNP; 10-9 to 10-4 mol/L), respectively, were obtained after incubating the vessel with incremental intravascular pressures of 50, 80 and 120 mm Hg for 60 minutes each.

Response to Ach was also obtained in different arteries after three consecutive incubation periods at 50 mm Hg.
A significant reduction in the vasodilator response to Ach was seen with increases in intravascular pressure. In contrast, response to SNP showed a non-significant trend to greater vasodilation with increases in pressure.

There was no difference in consecutive dose-response curves to Ach obtained at the same intravascular pressure.

Hypertension. 2000;36:941.