Granular juxtaglomerular cell hyperplasia caused by cyclosporine.

Histologic study of kidneys from rabbits given cyclosporine (CsA) revealed a marked hyperplasia of granular cells in the juxtaglomerular (JG) apparatus, but without a significant increase in the total cell number of JG cells. The increase in granular JG cells as compared with the control group was 204% and 406% for 30 mg/kg alternate days and 30 mg/kg daily groups, respectively. The increases for the lower-dosage groups were much smaller, although the increases were statistically significant for all but the 10 mg/kg alternate-days group. Other studies suggest that sympathomimetic activity of CsA may be the mechanism involved in granular JG cell hyperplasia.