Urinary Concentrations of Alpha-1-Microglobulin and Albumin in Patients with Reflux Nephropathy before and after Puberty

Abstract

We determined urinary concentrations of α₁-microglobulin and albumin in 155 patients with reflux nephropathy including 72 prepubertal (48 males and 24 females) and 83 postpubertal patients (43 males and 40 females) to elucidate the effect of age and gender in the progression of renal damage. Vesicoureteral reflux was resolved in all patients at least two years before enrollment into this study. Renal scarring was diagnosed with ^99mtechnetium dimercaptosuccinic acid renal scan. More severe renal scarring was found predominantly in male compared to female patients. Urinary α₁-microglobulin levels were significantly lower in postpubertal female patients (mean ± SD: 1.59 ± 1.02 mg/g creatinine) than in prepubertal males and females (3.32 ± 3.53 and 4.06 ± 4, respectively; p < 0.007 and p < 0.002, respectively), and in postpubertal males (3.69 ± 2.6; p < 0.002) regardless of severity of renal scarring. In the patients with severe unilateral renal scarring, urinary albumin levels were significantly higher in postpubertal males (81.9 ± 239.5) than in prepubertal males and postpubertal females (25.8 ± 63.1 and 13.8 ± 7.7, respectively; p < 0.05 and p < 0.05, respectively). Our results suggest that glomerular injury may develop during adolescence predominantly in male patients with severe renal scarring. In contrast, renal damage indicated by urinary α₁-microglobulon level appears to be ameliorated in female postpubertal patients. This gender difference may be attributed to sex hormones.