Insulin Therapy does not Interfere with Venous Endothelial Function Evaluation in Patients with Type 2 Diabetes Mellitus

Abstract

INTRODUCTION:Endothelium-dependent dilation is improved in insulin-treated diabetic patients, but this effect is probably due to improved glycemic control. The objective of the present study was to compare endothelium-dependent dilation in patients with well-controlled type 2 diabetes who are or are not using insulin as part of their therapy.METHODS:We studied 27 patients with type 2 diabetes (11 women, 60.3 years ± 6 years, with HbA1c < 7% and no nephropathy), including 16 patients treated with anti-diabetic agents (No-Ins, 8 women) and 11 patients treated with insulin alone or in combination with anti-diabetic agents (Ins, 3 women). Endothelial function was evaluated by the dorsal hand vein technique, which measures changes in vein diameter in response to phenylephrine, acetylcholine (endothelium-dependent vasodilation) and sodium nitroprusside (endothelium-independent vasodilation).RESULTS:Age, systolic blood pressure (No-Ins: 129.4 mmHg ± 11.8 mmHg, Ins: 134.8 mmHg ± 12.0 mmHg; P = 0.257), HbA1c, lipids and urinary albumin excretion rate [No-Ins: 9 mg/24 h (0-14.1 mg/24 h) vs. Ins: 10.6 mg/24 h (7.5-14.4 mg/24 h), P = 0.398] were similar between groups. There was no difference between endothelium-dependent vasodilation of the No-Ins group (59.3% ± 26.5%) vs. the Ins group (54.0% ± 16.3%; P = 0.526). Endothelium-independent vasodilation was also similar between the No-Ins (113.7% ± 35.3%) and Ins groups (111.9% ± 28.5%; P = 0.888).CONCLUSIONS:Subcutaneous insulin therapy does not interfere with venous endothelial function in type 2 diabetes when glycemic and blood pressure control are stable.

Effect of Acute Inspiratory Muscle Exercise on Blood Flow of Resting and Exercising Limbs and Glucose Levels in Type 2 Diabetes

“…In healthy subjects metaboreflex activation results in greater increases of sympathetic outflow during heavy exercise, resulting in attenuated reactive hyperemia, an indicator of endothelial function. In type 2 diabetes it is possible that the increased sympathetically-mediated vasoconstriction (metaboreflex activation) resulted in augmented vasoconstriction to a point that the already dysfunctional endothelium [ 30 ] was unable to allow for increased vasodilation. This is in accordance with previous data showing that subjects with diabetes had attenuated sensitivity to vasodilatory agents when leg blood flow was evaluated during the infusion of ATP; impaired peripheral vasodilatation may affect their ability to tolerate higher intensities of exercise due to low leg blood flow [ 31 ].…”

Reduced endothelial function in the skin in Southeast Asians compared to Caucasians

“…The test has been used in numerous studies to assess vascular endothelial function to show cardiovascular disease[30], vascular damage elicited by diabetes [6,31,32], and to assess the effect of ageing on vascular endothelial function [33]. The implication of this test is that reduced vascular endothelial function affects the blood flow to organs and impairs organ function.…”

Effects of diabetes on myocardial capillary density and serum angiogenesis biomarkers in male rats

“… 20 In the present study, the serum NO concentration in diabetic rats was lower than the concentration in the control group, which supports the results of previous studies. 21 - 24 Some possible mechanisms responsible for decreased NO production under high glucose conditions include the suppression of endothelial NO synthase expression and activity, 25 overproduction of superoxides, 26 and activation of protein kinase C. 23 …”