Studies On The Clinical Significance Of The Detection Of Urinary Type Ⅳ Collagen In The Diagnosis Of Patients With Early Diabetic Nephropathy

Objectives: To explore the relation between the concentration of urinary type IVcollagen and diabetic nephropathy and value its clinical significance in the diagnosis of early diabetic nephropathy.Methods: Using radioimmunoassay to measure urinary and seminal type IVcollagen simultaneously in 20 healthy persons(group A),20 primary glomerular disease (group B) and 69 diabetic patients(group C).With immunohistochemical examination of expression of type IV collagen in kidney ,4 diabetic nephropathy patients,6 primary glomerular disease cases and 2 healthy persons were studied. Results: Urinary type IV collagen excretion was significantly increased in patients with type2 diabetic mellitus. By comparison, urinary IV collagen in diabetic patients with normalalbuminuria(groupClX24.67?2.49ug/L)began to go up, and that of in microalbuminuria(groupC2X39.41?2.61ug/L) and macroalbuminuria (groupC3) (67.45 ?1.74ug/L) patients were significantly higher than that of group A(6.06?6.03ug/L) and group B (13.23 ?8.3lug/L) (p<0.01),But group Cl was not different from group B. With the 24-hour urinary albumin excretion increased ,the discrepancy of urinary type IV collagen between all groups of diabetic mellitus was remarkable. The concentration of urinary type IV collagen was significantly positively correlated with HbAlC, urinary albumin and PBG, it increased with the severity of diabetic nephropathy. the positive incidence of urinary type IV collagen in diabetic patients with normal UAER was 47.5%, it was. similar with report related. The concentration of serumal type IV collagen was not different between all groups. Immunohistochemistry results implied immunoactive type IV collagen detected in glomerular basement membrane (GBM),tubular basement membrane and extra cellular matrix(ECM) in patients with primary glomerular disease was more than that of in the normal persons, but the expression of type IV collagen in patients with type2 diabetic mellitus was much more than that of primary glomerular disease(p<0.01). Conclusions: The concentration of serumal type IV collagen was not different in all groups, it had no correlation with urinary type IV collagen increased, so it could not be used to predict DN; Urinary type IV collagen was positively related with PBG and HbAlC,it implied that strict control PBG and HbAlC were beneficial to prevent and treat DN, Urinary type IV collagen was positively related with UAER and A1MG, it could reflect the severity of injury in glomerulus and renal tubules in DN, measurement of Urinary type IV collagen may be a better ,earlier, specific indicator to predict DN, We advice the concentration of Urinary type IV collagen over 15.95ug/L a indictor in the diagnosis of early DN.