Microvascular function in type 2 (non-insulin-dependent) diabetes: improved vasodilation after one year of good glycaemic control.

Abnormalities of microvascular function may be important in the development of diabetic microangiopathy. The major functional abnormality identified in patients with Type 2 diabetes has been a marked limitation of microvascular vasodilation, which is present from the time of diagnosis. The effects of sustained improvements in glycaemic control on vasodilator capacity in Type 2 diabetes are unknown. Twelve Type 2 diabetic patients were studied prospectively for 1 year after diagnosis. The reduced maximum hyperaemic response to local heating of the foot skin present at the time of diagnosis remained unchanged after 3 months of improved glycaemic control (1.12 +/- 0.56 V at diagnosis vs 1.21 +/- 0.69 V at 3 months, mean +/- SD; p = 0.25), but was improved after 1 year (1.42 +/- 0.91 V; p = 0.04 vs 3 months). The percentage increase in maximum hyperaemia correlated with the percentage decrease in HbA1c (rs = 0.53, p = 0.04). These results suggest that the early microvascular abnormalities demonstrated in Type 2 diabetes are potentially reversible and provide a further reason for striving for optimal glycaemic control in this patient group.