Interaction of hypertension and diabetes on impairment of endothelial function

To investigate whether the interaction of hypertension and diabetes aggravates endothelial dysfunction and leads to smooth muscle dysfunction.

Noninvasive methods were used to the investigated patients with type 2 diabetes mellitus (2-DM) (Group 1), patients with hypertension (Group 2) and patients with both 2-DM and hypertension (Group 3), as well as a normal control group (Group 4) by studying a brachial artery without evidence of atherosclerotic plaque formation.

Results showed that endothelium-dependent vasodilation decreased significantly in Group 1 (5.74% +/- 3.32%, P < 0.05), Group 2 (4.14% +/- 2.93%, P < 0.01), and Group 3 (2.78% +/- 2.08%, P < 0.001) as compared to the control (9.45% +/- 3.88%). The nitroglycerin-induced vasodilation (smooth muscle function) in Group 3 was significantly decreased as compared to the control group (14.11% +/- 4.63% vs 23.53% +/- 6.77%, P < 0.001), but there were no differences in nitroglycerin-induced vasodilation between Group 1, Group 2 and Group 4. On univariate analysis, a reduced vasodilator response to nitroglycerin was associated with endothelium-dependent vasodilation (r = 0.54, P < 0.001).

Our results indicate that the interaction of 2-DM and hypertension aggravates endothelial dysfunction and further impairs the smooth muscle function.