Aquaporin-2 and NKCC2 expression pattern in patients with hepatosplenic schistosomiasis

Objective Schistosoma mansoniinfection is considered a public health problem. Glomerular involvement in schistosomiasis is a well-documented complication, especially in hepatosplenic schistosomiasis (HSS). However, renal tubular function is poorly understood. The aim of this study was to investigate, through urinary exosomes, tubular transporters functionally in HSS patients. Methods Cross-sectional study of 20 HSS patients who had isolated exosomes from urine samples. Protease inhibitor was added in the urine samples who were immediately frozen at -80 degrees C for further exosomes isolation. After urine had thawed, urinary exosomes were obtained using extensive vortexing, centrifugation and ultracentrifugation steps of urine. Urinary transporters expression from exosomes was evaluated by western blot, including NHE3, AQP2 and NKCC2. Charge amounts for gel electrophoresis were adjusted by urinary creatinine concentration of each patient to avoid urinary concentration bias. All protein expression of HSS patients was relative to healthy controls. Results The expression of aquaporin-2 (AQP2) was lower in HSS patients than in controls (46.8 +/- 40.7 vs. 100 +/- 70.2%,P = 0.03) and the expression of the NKCC2 co-transporter was higher (191.7 +/- 248.6 vs. 100 +/- 43.6%,P = 0.02). Conclusions The decrease of AQP2 and the increase of NKCC2 expression in HSS patients seem to be involved with the inability of urinary concentration in these patients. These data show renal tubular abnormalities in HSS patients without manifest clinical disease.