Source: Diabetologia  |  Posted 9 years ago

Insulin enhances coronary artery vasodilation to similar degrees in both healthy subjects and patients with type I diabetes mellitus.

Short-term hyperglycemia does not abolish insulin-induced vasodilation or alter myocardial blood flow in diabetic patients receiving insulin, report investigators from the University of Turku in Turku, Finland.

The investigators used positron emission tomography to measure myocardial blood flow at baseline and after adenosine infusion in nine type I diabetic males and in10 healthy controls, with or without insulin infusion. Diabetic patients were non-smokers and had no diabetic complications. They were studied during normoglycemia and during hyperglycemia that was induced by lowering their insulin dose for two days.

Results showed similar resting myocardial blood flow in the two groups. Adenosine infusion caused a 23 percent lower stimulation of flow in diabetic compared with non-diabetic subjects.

Insulin administration increased adenosine stimulated flow by 23 percent in diabetic subjects and 17 percent in non-diabetic subjects.

Short-term hyperglycemia did not alter flow values from those during normoglycemia.

Insulin-induced coronary vasodilation might contribute to the beneficial effects of insulin therapy on myocardial ischemia previously observed in diabetic patients, the investigators suggest.