AORTIC COLLAGEN ALTERATIONS IN HUMAN DIABETES-MELLITUS - CHANGES IN BASEMENT-MEMBRANE COLLAGEN CONTENT AND IN THE SUSCEPTIBILITY OF TOTAL COLLAGEN TO CYANOGEN-BROMIDE SOLUBILIZATION

Structural alterations in arterial extracellular matrix components have been suggested to play a role in the development of arterial disease among patients with diabetes mellitus. This study examines the quantity and quality of collagenous components in aortas from diabetic patients. In order to obtain data about the arterial tissue concentration of type IV and V collagen in diabetic and non-diabetic patients, aortas from 21 patients with diabetes (9 with Type 1 (insulin-dependent) diabetes and 12 with Type 2 (non-insulin-dependent) diabetes), were collected at autopsy together with aortas from groups of sex- and age-matched patients. Intima and media samples from normal and fibrous plaque areas from the individual vessels were evaluated. Pulverized, dried and defatted tissue samples were subjected to chemical solubilization with cyanogen bromide and subsequent immunochemical quantitation of the dissolved type IV and V collagen in an ELISA. It was found that the concentration of type IV collagen was increased in the tunica media both in plaque and non-plaque areas in the samples from the diabetic patient groups as compared to the non-diabetic groups. No consistent differences in type IV collagen concentrations were found between diabetic and non-diabetic patients in tunica intima. The type V collagen concentrations and the total collagen content were not altered in the diabetic samples. The fraction of the total collagen that was solubilized during cyanogen bromide treatment was determined, and it was found that this fraction was decreased in most tissue areas in the diabetic patient groups. These findings suggest that patients with diabetes develop alterations in arterial collagenous components that may play a role in the development of arterial disease in diabetes.