The association between plasma beta-hexosaminidase and its isoenzyme patterns and retinopathy in type 1 diabetes mellitus.

beta-Hexosaminidase and its isoenzyme patterns were investigated in plasma from patients with Type 1 diabetes mellitus. The patients were divided into three main groups matched for duration of diabetes: (a) proliferative retinopathy (b), progress of retinopathy within a two-year period (c) and with no background retinopathy. When all patients were compared to a reference group, a significant increase of plasma beta-hexosaminidase activity was found. Patients with proliferative retinopathy had significantly increased activity of plasma beta-hexosaminidase compared to the reference group but not compared to the other diabetic patients. The isoenzyme distribution was not different in any of the diabetic subgroups compared to the reference group. It was also shown that various degrees of diabetic nephropathy did not influence total plasma Hex or the isoenzyme pattern.