Determinants of Glomerular Volume in Different Cortical Zones of the Human Kidney

Enlarged glomerular size is a feature of focal segmental glomerulosclerosis, obesity-related glomerulopathy, diabetic nephropathy, and hypertension. The distribution of glomerular volumes within different cortical zones and glomerular volume alterations with age and obesity may contribute to understanding the evolution of these diseases. We analyzed the distributions of volumes of individual glomeruli in the superficial, middle, and juxtamedullary cortex of normal human kidneys using the disector/Cavalieri method. Volumes (V_glom) of 720 nonsclerotic glomeruli (30 per kidney, 10 per zone) were estimated in autopsy kidneys of 24 American men, 12 aged 20 to 30 yr and 12 aged 51 to 69 yr. Black and white individuals were represented equally. The range of individual V_glom within subjects varied from two- to eight-fold. There were no significant zonal differences in V_glom in the young or those with body surface area (BSA) ≤ 2.11 m². In contrast, superficial glomeruli in the older age group, in those with BSA > 2.11 m², and in white subjects were significantly larger than juxtamedullary glomeruli. Black subjects tended toward larger V_glom than white subjects, and this difference was significant and most marked in the juxtamedullary zone and independent of age, BSA, and glomerular number. There is a wide range in individual V_glom in adults. BSA, race, and age independently influence V_glom in different zones of the renal cortex. These findings might reflect processes of aging and susceptibility factors to renal disease.