FO023
CLINICAL SIGNIFICANCE OF URINARY PODOCYTE-DERIVED MICROPARTICLE DETECTION FOR MEMBRANOUS NEPHROPATHY THERAPY

INTRODUCTION AND AIMS: Elevated levels of podocyte-derived microparticles might reflect podocyte injury in renal diseases. Immunological stress and other insulting factors may injure podocytes. This study aimed to observe the change in urinary podocyte-derived microparticle levels in idiopathic membranous nephropathy (IMN) and to figure out its potential clinical significance as biomarkers in IMN therapy.

METHODS: Before initial immunosuppressive therapy, we prospectively enrolled IMN patients (n= 30) diagnosed by renal tissue pathology using periodic acid-schiff staining and periodic acid-silver methenamine staining by light microscopy and ultra-microstructural observation by electron microscopy. After isolation from urine samples, total microparticles(Annexin V positive)and podocyte microparticles (podocalyxin positive) were characterized by flow cytometry. Ten IMN patients were studied again after the six-month treatment of glucocorticoids combined with tacrolimus intervention. Healthy volunteers (HVs) (n= 18) served as controls. The correlation of urinary microparticles with clinical and pathological factors in IMN patients was analysed.

RESULTS: The fraction of podocyte microparticles among total urinary microparticles was elevated in IMN patients compared with HVs (P<0.01). After six months of treatment, the levels of urinary podocyte-derived microparticles were significantly decreased with the recovery of abnormal clinical parameters. Baseline levels of podocyte-derived microparticles were positively correlated with age, serum cholesterol, triglyceride and blood urea nitrogen.

CONCLUSIONS: The excretion of urinary podocyte-derived microparticles may reflect podocyte injury, and the variation of their levels might be useful for monitoring disease activity and therapy response in patients with IMN.