Pietravalle P, Morano S, Cristina G, De Rossi M G, Mariani G, Cotroneo P, Ghirlanda G, Clementi A, Andreani D, Di Mario U
Department of Endocrinology, University La Sapienza, Rome, Italy.
Diabetes. 1991 Dec;40(12):1685-90. doi: 10.2337/diab.40.12.1685.
To investigate the role of protein charge in early diabetic proteinuria, the clearance of proteins differing in charge and/or size (anionic and cationic Igs, albumin) was evaluated in 98 insulin-dependent (type I) diabetic patients selected as a representative sample of the 418 patients attending our clinics. Of the patients, 12.9% were microalbuminuric and 4.8% were macroalbuminuric. Anionic and total IgG clearances were significantly increased in 30.6 and 12.2% of patients and were correlated with duration of disease. Anionic IgG4 clearances were increased in patients (9.2%) with normal IgG excretion, suggesting that charge-selectivity impairment is responsible for protein loss. Anionic Ig clearances were also higher in some patients (14.3%) with normal albumin clearance, probably as a result of different glomerular filtration and/or tubular reabsorption. The anionic-cationic IgG clearance ratio tended to increase in parallel with albumin clearance, but once above macroalbuminuric levels, it tended to fall again, indicating the concomitant presence of size-selectivity loss. The anionic IgG clearance and the anionic-cationic IgG ratio, in addition to albumin excretion, may be valuable in assessing early kidney protein charge-selectivity impairment and better characterizing normoalbuminuric patients and those in the preclinical stage of diabetic nephropathy.
为研究蛋白质电荷在早期糖尿病蛋白尿中的作用，我们在98例胰岛素依赖型（I型）糖尿病患者中评估了电荷和/或大小不同的蛋白质（阴离子和阳离子免疫球蛋白、白蛋白）的清除率，这些患者是从在我们诊所就诊的418例患者中选取的具有代表性的样本。患者中，12.9%为微量白蛋白尿，4.8%为大量白蛋白尿。30.6%和12.2%的患者阴离子和总免疫球蛋白清除率显著升高，且与病程相关。在免疫球蛋白排泄正常的患者中（9.2%）阴离子IgG4清除率升高，提示电荷选择性受损是蛋白质丢失的原因。在一些白蛋白清除率正常的患者中（14.3%）阴离子免疫球蛋白清除率也较高，这可能是不同的肾小球滤过和/或肾小管重吸收的结果。阴离子-阳离子免疫球蛋白清除率比值倾向于与白蛋白清除率平行升高，但一旦超过大量白蛋白尿水平，又倾向于再次下降，表明同时存在大小选择性丧失。除白蛋白排泄外，阴离子免疫球蛋白清除率和阴离子-阳离子免疫球蛋白比值可能有助于评估早期肾脏蛋白质电荷选择性受损情况，并更好地对正常白蛋白尿患者以及处于糖尿病肾病临床前期的患者进行特征描述。
