Vascular insulin abnormalities, hypertension, and accelerated atherosclerosis

Area of Science:

• Endocrinology
• Cardiovascular Medicine
• Metabolic Disorders

Background:

• Insulin resistance, glucose intolerance, and hyperinsulinemia are linked to hypertension.
• Hyperinsulinemia has been implicated in the development and progression of high blood pressure.
• Recent studies suggest cellular insulin resistance, rather than hyperinsulinemia, may be a primary driver of hypertension.

Purpose of the Study:

• To propose that cellular insulin deficiency is a common mechanism in hypertension development for both type I and type II diabetes mellitus.
• To investigate the role of insulin in modulating cellular calcium metabolism and its link to hypertension and atherosclerosis.
• To explore how impaired insulin response in vascular smooth muscle cells contributes to increased vascular tone.

Main Methods:

• Review of accumulating evidence linking insulin resistance and hypertension.
• Analysis of recent laboratory data on insulin's effect on vascular smooth muscle cells.
• Examination of insulin's role in cellular calcium metabolism.

Main Results:

• Persons with hyperinsulinemia but normal glucose tolerance exhibited higher blood pressure than normoinsulinemic individuals.
• Our laboratory data suggest cellular insulin resistance, not hyperinsulinemia, may lead to hypertension.
• Insulin normally attenuates vascular contractile responses to vasoactive factors, indicating insulin resistance is associated with enhanced vascular reactivity.

Conclusions:

• Cellular insulin deficiency is a proposed common mechanism in hypertension development across diabetic types.
• Decreased insulin action on vascular smooth muscle cells may contribute to hypertension and atherosclerosis.
• Impaired cellular insulin response leads to increased vascular smooth muscle tone, a hallmark of diabetic hypertension.