Peritubular capillaries and renal function in pediatric idiopathic nephrotic syndrome

Nephrotic syndrome (NS) is a common renal disorder with significant tubulo-interstitial damage due to the combined effects of proteinuria and obstruction of efferent blood flow. Peritubular capillary (PTC) loss has also been correlated with interstitial fibrosis. This study included 30 pediatric cases of idiopathic NS. Clinical details, including biochemical parameters, were recorded and renal biopsy slides were reviewed for histological features. PTCs were highlighted using anti-CD34 antibody and quantified with the help of image analysis software. Postmortem kidney biopsies from seven children were taken as controls for quantification of PTCs and interstitial fibrosis. Wherever possible, as ultrastructural examination of the renal biopsy was performed. Appropriate statistical methods were applied. Patients with minimal change disease (MCD) had lower serum creatinine as compared with those with focal and segmental glomerulosclerosis (FSGS). Similarly, tubular atrophy and interstitial fibrosis were significantly lower in MCD than in FSGS. PTC density was lower in all groups of NS as compared with the controls. Biopsies with FSGS had a lower PTC density compared with both MCD and mesangioproliferative glomerulonephritis. PTC density showed a negative correlation with serum creatinine and degree of proteinuria. PTC loss appears to play an important role in the development of renal biopsy changes in pediatric NS. This aspect of the renal vasculature requires further study in idiopathic NS.