Glomerular growth under cyclosporine treatment in childhood nephrotic syndrome

BACKGROUND: Glomerular hypertrophy is important in children with idiopathic nephrotic syndrome in regard to diagnosis and pathogenesis. Moreover, glomerular growth may be altered by cyclosporine (CsA) treatment in these patients. METHODS: Bowman's area (BA) and the glomerular tuft area (GA) of pre- and post-treatment biopsies was measured by morphometry in 47 children with idiopathic nephrotic syndrome (39 MCD and 8 FSGS) treated with CsA and low-dose prednisolone for up to 2 years. RESULTS: BA and GA increased with age. The mean BA and GA were 1.2 times larger in FSGS than in MCD and the proportional increase was similar in both diseases after treatment. BA and GA decreased in 48.9% and 40.4% of cases after treatment, respectively, whereas tubulointerstitial lesion (TIL) developed in 27.7%. BA and GA decreased to 10.4% and 8.3%, respectively in children who developed TIL after treatment and the values were largely unchanged in those treated for more than 16 months. CONCLUSIONS: Glomerular growth is hampered by CsA nephrotoxicity, which is a more common complication than TIL. The impairment of glomerular growth is related to the duration of treatment and the development of TIL, but not to age or diagnosis.