Serum levels of carboxy-terminal propeptide of human type I procollagen are an indicator for the progression of diabetic nephropathy in patients withType 2 diabetes mellitus

The finding that glomerular mesangial cells produce human type I collagen s uggests that the serum levels of carboxy-terminal propeptide of human type I procollagen (P1CP) may reflect the severity of diabetic nephropathy. We t herefore investigated the relationship between serum P1CP levels and the ex tent of diabetic complications in 100 patients (46 males and 54 females) wi th Type 2 diabetes and in 64 healthy subjects. Serum P1CP was determined by radioimmunoassay-In diabetes, we defined P1CP levels less than 142 ng/ml a s a normal P1CP group (group A), whereas we defined them as equal to or gre ater than 142 ng/ml as a high P1CP group (group B). The diabetic patients h ad significantly elevated serum P1CP levels compared with the controls. The prevalence of hypertension, proliferative diabetic retinopathy or macroalb uminuria was significantly higher in group B than in group A. Serum P1CP le vels showed a significant positive correlation with urinary albumin excreti on, but not with fasting blood glucose, glycosylated hemoglobin A(1c) or se rum osteocalcin. Macroalbuminuric patients showed significantly higher P1CP levels than the normoalbuminuric patients. In patients in the absence of d iabetic nephropathy, no significant differences of P1CP levels were found a mong the severity of diabetic retinopathy. The present results suggest that serum P1CP levels reflect the progression of diabetic nephropathy in patie nts with Type 2 diabetes. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.