Tan Yan, Yang Yongnian, Zhang Zhigang, Zhang Xiurong, Zhang Zuchuan, Liu Yinkun
Department of Endocrinology and Metabolism, Zhongshan Hospital, Medical College of Fudan University, Shanghai 200032, China.
Chin Med J (Engl). 2002 Mar;115(3):389-94.
To determine whether urinary type IV collagen can serve as an indicator specific for diabetic nephropathy.
Using a novel sandwich ABC-ELISA to measure type IV collagen directly, the 24-hour urinary type IV collagen excretion rate was determined in 120 diabetic patients and some groups of controls. Urinary albumin determinations were made with a RIA kit at the same time. A total of 13 diabetic patients with microalbuminuria underwent percutaneous renal biopsy for definitive diagnosis of diabetic nephropathy. Type IV collagen and TGF-beta 1 immunoreactivities were detected with ABC methods in renal biopsies.
Urinary type IV collagen excretion was significantly increased in diabetic patients with microalbuminuria, especially those with albumin excretion above 200 mg/24 h. By comparison, collagen excretion was equivalent to that in healthy controls when measured in diabetics with normalbuminuria and in patients with primary glomerular disease, primary hypertension, or coronary heart disease. Urinary type IV collagen excretion in diabetics was negatively correlated with creatinine clearance. In renal biopsies from subjects with elevated collagen excretion, the glomeruli showed pathological changes typical of diabetic nephropathy. Also, excessive type IV collagen and TGF-beta 1 immunoreactivity were detected in the glomeruli, Bowman's capsule and interstitium.
Excretion of type IV collagen, possibly reflecting increased production or decreased degradation of this protein, may be a clinically useful indicator of incipient diabetic nephropathy.
确定尿Ⅳ型胶原是否可作为糖尿病肾病的特异性指标。
采用新型夹心ABC-ELISA法直接测定Ⅳ型胶原，对120例糖尿病患者及部分对照组测定24小时尿Ⅳ型胶原排泄率。同时用放射免疫分析试剂盒测定尿白蛋白。对13例微量白蛋白尿的糖尿病患者进行经皮肾活检以明确诊断糖尿病肾病。用ABC法检测肾活检组织中的Ⅳ型胶原和转化生长因子β1免疫反应性。
微量白蛋白尿的糖尿病患者尿Ⅳ型胶原排泄显著增加，尤其是白蛋白排泄量高于200mg/24h的患者。相比之下，在白蛋白尿正常的糖尿病患者以及原发性肾小球疾病、原发性高血压或冠心病患者中，胶原排泄量与健康对照组相当。糖尿病患者尿Ⅳ型胶原排泄与肌酐清除率呈负相关。在胶原排泄增加的受试者的肾活检中，肾小球呈现出糖尿病肾病的典型病理变化。此外，在肾小球、鲍曼囊和间质中检测到过量的Ⅳ型胶原和转化生长因子β1免疫反应性。
Ⅳ型胶原的排泄可能反映该蛋白产生增加或降解减少，可能是早期糖尿病肾病的一项临床有用指标。
