PS-C33-3: THE EFFECT OF AGE AND HYPERTENSION ON PODOMETRICS IN DIFFERENT CORTICAL ZONES OF THE HUMAN KIDNEY

Abstract

Objective: Podocyte loss and resultant nephron loss are common processes in the progression of glomerulosclerosis and CKD. Aging and hypertension are the main causes of benign nephrosclerosis, which is histologically characterized by concomitant appearances of glomerular collapse and enlargement. Glomerular hypertrophy and glomerulosclerosis often preferentially occur in specific cortical zones of the kidney, possibly due to the difference in kidney artery perfusion. However, it is unknown if podometrics, such as podocyte number per glomerulus, podocyte density and podocyte volume, differ among different cortical zones in the human kidneys. The aim of the present study is to determine the effect of aging and hypertension on podometrics in different cortical zones of the human kidneys. Design and method: Autopsy kidneys from 50 Japanese adults without apparent glomerular disease were cross-sectionally analyzed. Podometrics in different cortical zones (superficial/middle/juxtamedullary) were estimated on a single section using a model-based stereology. Results: Median age was 68 years and median eGFR was 73.5 mL/min/1.73m2. Hypertension was identified in 21 (42%) subjects. While podocyte number per glomerulus was similar in the three zones, superficial glomeruli were the smallest and had the highest podocyte density and smallest podocytes. Increasing age and hypertension were associated with lower podocyte number, with age mostly affecting superficial glomeruli, and hypertension mostly affecting juxtamedullary glomeruli. There was no significant interaction between age and hypertension (Figure). Neither podocyte density, podocyte volume nor volume density of podocytes in glomeruli was associated with age or hypertension. Conclusions: Podometric changes, especially decreased podocyte number per glomerulus, may also contribute to the development and different distribution of glomerular morphological phenotypes in aging and hypertension-related benign nephrosclerosis.