Abstract
Capillary basement membrane thickening is a characteristic of diabetic microangiopathy. Type IV collagen is the major component of basement membrane. To elucidate the pathogenesis of diabetic nephropathy, we investigated serum type IV collagen and serum ascorbic acid in non-insulin-dependent diabetes mellitus (NIDDM) (n=37) and in normal subject s (n=14). Serum ascorbic acid level was lower in NIDDM than in normal subjects. Serum type IV collagen level was higher in NIDDM than in normal subjects. There was a significant positive correlation between serum type IV collagen and HbA_<IC> in poorly controlled diabetes (HbA_<IC>>8%) (p<0.05). A significant negative correlation was found between serum type IV collagen and serum ascorbic acid (p<0.05). A significant positive correlation was found between serum type IV collagen and urinary albumin excretion in patients with microalbuminuria (U-alb>30 mg/g・Cr) in NIDDM. In conclusion, serum type IV collagen is helpful as a early indicator of nephropathy.
