[Expression and clinical implication of platelet-derived growth factor-D and platelet-derived growth factor-beta in childhood IgA nephropathy].

OBJECTIVE: To investigate the clinical implication of platelet-derived growth factor (PDGF)-D and PDGF-beta in IgA nephropathy in childhood. METHODS: Forty-seven children with IgA nephropathy and 26 controls were enrolled for study, and their serum, urine and renal biopsy specimens were examined. The patients were divided into control group [including serum, urine specimens of 13 healthy children and 13 renal biopsy samples of non-IgA nephropathy in children], mild proliferation (MP) group (13 patients), focal proliferation (FP) group (19 patients), and proliferation sclerosis (PS) group (15 patients). Enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry were used to determine contents of PDGF-D, PDGF-beta and PDGF-B in blood, urine and renal tissues. The levels of 24-hour urinary protein excretion, serum albumin (Alb), serum blood urea nitrogen (BUN) and creatinine (Cr) were also determined. RESULTS: Compared with control group, levels of PDGF-D and PDGF-B were progressively elevated in blood and urine of IgA nephropathy children with increase in severity of glomerular damage (all P<0.01). Serum as well as urinary PDGF-D and PDGF-B levels were positively correlated with 24-hour urinary protein excretion (PDGF-D blood: r=0.546, urine: r=0.760; PDGF-B blood: r=0.634, urine: r=0.577, respectively, P<0.01), while negatively correlated with serum Alb levels in IgA nephropathy patients (PDGF-D blood: r=-0.649, urine: r=-0.528; PDGF-B blood: r=-0.613, urine: r=-0.531, respectively, P<0.01). Contents of PDGF-D and PDGF-beta in renal tissue were much higher than those of control group (P<0.01). Along with the increase in severity of glomerular pathology, their contents increased gradually. PDGF-B was only significantly expressed in renal tissue in FP group and PS group. CONCLUSION: PDGF-D might significantly enhance the development of mesangial proliferation and tubulointerstitial fibrosis. In comparison with PDGF-B, PDGF-D appears to reflect more sensitive to the severity and prognosis of IgA nephropathy.