Loss of renal tissue in the elderly

Eighty-eight kidneys obtained at necropsy from normotensive subjects aged over 50 years were examined histologically and by post-mortem pyelography and angiography. Moderate or severe scarring was present in 50%. Its distribution and the absence of calyceal deformity make pyelonephritic scarrig unlikely. Its extent was related to the severity of change in the renal vessels, but not to age. On pyelograms, scarring was difficult to distinguish from fetal lobation. Kidneys with the most severe histological changes in the vessels tended to show the most marked angiographic distortion, though in general the two techniques examine different parts of the renal vascular bed. Total renal area and "cortical" area, measured from the angiograms, were not significantly correlated with age, thouth both tended to be smaller in older subjects. These dimensions, particularly cortical area, were significantly correlated with vascular changes, being smallest when vessels were most markedly affected. Results suggest that the loss of renal tissue which occurs in the elderly, particularly selective loss of cortex, is more closely related to events in the renal vasculature than to age itself.