SERUM CONCENTRATIONS OF BASEMENT-MEMBRANE PROTEINS IN NIDDM AS A PROGNOSTIC MARKER FOR NEPHROPATHY

Metabolic changes of basement membrane proteins, collagenous and non-c ollagenous, will be followed by morphological changes and develop into diabetic microangiopathy, In this study, serum concentrations of lami nin and type IV collagen were measured in 87 cases of non-insulin-depe ndent diabetes mellitus (NIDDM) and examined with the development of d iabetic nephropathy and retinopathy. Serum type IV collagen was measur ed by two methods, assays of the 7S portion (7S-RIA) and of both the 7 S and central triple helical domain (IV-EIA). IV-EIA showed more signi ficant elevation with development of diabetic microangiopathy than 7S- RIA and laminin. After measurement of basement membrane proteins, 66 c ases were followed clinically for 3 or 4 years. In 45 cases without wo rsening of diabetic nephropathy, IV-EIA and laminin concentrations in serum were significantly lower than those in 21 cases who showed worse ning of diabetic nephropathy in the same period. Multivariate analysis revealed a good model including three dependent variables of serum va lues of laminin, IV-EIA and mean blood pressure for discriminating bet ween the worsened group and the non-worsened group, High values of IV- EIA and laminin in serum may be useful in predicting the worsening of diabetic nephropathy.