Widening of foot processes in normoalbuminuric adolescents with type 1 diabetes.

We compared renal morphology in normoalbuminuric adolescents with type 1 diabetes with age-and sex-matched controls. Renal morphological measurements in 46 unselected adolescents with diabetes for approx. 10 years were compared with those in 20 healthy kidney donors. Renal volume estimated by ultra-sound, renal function determined by clearances of inulin and para-aminohippurate, and long-term mean HbA(1c) were measured in the patient group. Basement membrane thickness (BMT), mesangial matrix and capillary volume fractions per glomerulus [V(V)(matrix/glom), V(V)(cap/glom)] were significantly greater in patients than in controls (505 nm, 10.5%, 46.7% vs. 320 nm, 7.9% and 39.3%). The foot processes were wider in patients than in living donors (414 nm vs. 372 nm). There was no difference in mean kidney volume of patients with diabetes and healthy subjects. Glomerular filtration rate, body weight, and slit pore length density explained 60% of the variance in renal volume. After about 10 years' duration of type 1 diabetes, BMT, V(V)(matrix/glom), V(V)(cap/glom), and foot process width were greater in normoalbuminuric adolescents than in healthy controls. This increase in foot processes of normoalbuminuric patients has not been reported before.