Urinary Podocyte Can Be an Indicator for the Pathogenetic Condition of Patients with IgA Nephropathy

Background: To evaluate the clinical significance of the urinary podocytes in patients with IgA nephropathy. Methods: Urine samples from 102 biopsy-confirmed IgA nephropathy patients were collected to detect urinary podocytes using an indirect immunofluorescence staining method with anti-human Podocalyxin (PCX) antibody. Then, correlation analysis was performed between the urinary podocyte counts and the clinicopathological changes. Results: Upon comparison with IgA nephropathy patients with negative urinary podocytes, IgA nephropathy patients with positive urinary podocytes presented a significant reduction in plasma albumin and glomerular filtration rate and remarkable rise in urinary protein excretion, blood cholesterol, and mean arterial pressure. Pathologically, the renal tissues of IgA nephropathy patients with positive urinary podocytes presented less podocytes in the glomerulus (6.03 +/- 3.61 cells/glomerulus vs. 12.58 +/- 7.23 cells/glomerulus, p < 0.001), more mesangial matrix, and more aggravated interstitial fibrosis and foot process fusion than in IgA nephropathy patients with negative urinary podocytes. In addition, the urinary podocyte counts were positively correlated with serum creatinine and 24-hour urinary protein excretion (r = 0.332, p < 0.05 and r = 0.387, p < 0.05, respectively) and negatively correlated with the number of podocytes in the renal tissues (r = -0.416, p 0 < 0.05). Conclusions: Detection of urinary podocytes can be a noninvasive indicator for reflecting the severity of IgA nephropathy.