Association between podocytes and proteinuria in Alport syndrome / 中华肾脏病杂志

ABSTRACT

Objective To investigate the association between podocytes and proteinuria in children with Alport syndrome. Methods Twenty-one children including 13 boys and 8 girls with Alport syndrome were divided into 3 groups according to 24-hour urinary protein, ＜30 mg/kgas the mild proteinuria group (10 patients), 30 to 50 mg/kg as the moderate proteinuria group (4 patients) and ＞50 wg/kg as the heavy proteinuria group (7 patients). The correlation between foot process width and the degree of proteinuria was analyzed. By immunoperoxidase staining on renal tissue, the key slit diaphragm molecules nephrin, podocin and podocyte cytoskeleton-associated molecule synaptopodin were studied. Results The foot process width (420-2270 nm) in patients with Alport syndrome was positively correlated with proteinuria significantly (r=0.765, P＜0.01).Foot process width was significantly lower in patients with mild proteinuria [475 (420-900) nm)compared with that in patients with heavy proteinuria [1520 (480-2270) nm] (P＜0.05). In Alport syndrome children with heavy proteinuria, the distribution of nephrin and podocin changed dramatically. In two children with shorter proteinuria period (1 year), dramatic distribution change of nephrin and podocin occurred, however, the foot process along with synaptopodin preserved.Conclusions Podocyte foot process effacement and injury of slit diaphragm participate in the mechanism of proteinuria in Alport syndrome. The injury of slit diaphragm seems to be an early event in the development of foot process effacement in Alport syndrome, which may guarantee early treatment.