Serum and Urinary Concentrations of Type IV Collagen and Laminin as a Marker of Microangiopathy in Diabetes

Serum and urinary concentrations of type IV collagen and laminin were measured by enzyme‐linked immunosorbent assay (ELISA) in diabetic patients and compared with normal control subjects. In diabetic patients with proteinuria or with renal insufficiency, serum and urinary concentrations of type IV collagen were higher than those of control subjects (p < 0.005). Furthermore urinary concentrations of type IV collagen and laminin were significantly higher in diabetes, even in the absence of nephropathy, than in normal controls (p < 0.05). Urinary concentrations of type IV collagen in patients with diabetes and microalbuminuria (0.73 ± 0.11 mg mmol⁻¹) were significantly higher than in diabetic patients without nephropathy (0.40 ± 0.060 mg mmol⁻¹) (p < 0.025). Urinary concentrations of type IV collagen may have a role as an indicator of early diabetic nephropathy. Serum concentrations of type IV collagen in diabetic patients with retinopathy were significantly higher than in normal controls (p < 0.025). However, urinary concentrations of type IV collagen (p < 0.05) and serum concentrations of laminin (p < 0.025) were significantly higher in diabetic patients than normal controls and the difference between patients with and without retinopathy was not significant. 1992 Diabetes UK