Morphometrical and functional correlations in benign nephrosclerosis

To ascertain whether or not vascular lesions lead to renoparenchymal damage through ischemia and to a deterioration of renal function in patients with essential hypertension, correlations among morphometrical findings and renal function were examined in 36 renal biopsies from Japanese patients with a benign nephrosclerosis. The following histological parameters were investigated; glomerular sclerotic index (GS), interstitial volume (IV), measured by the point-counting method, index of arteriolar hyaline change (HC) and intimal thickening (IT), determined by morphometry. Arteries were divided into two groups; those with less than 3 layers of medial smooth muscle cells (SMC less than 3) and those with more than 3 cell layers (SMC greater than or equal to 3). The mean of IT in each size was calculated. IT (SMC less than 3) showed a significant correlation with GS and IV. IT (SMC less than 3), GS and IV significantly correlated with Ccr. On the other hand, IT (SMC greater than or equal to 3) and HC showed no correlation with GS nor Ccr. IT (SMC less than 3) and HC correlated with both blood pressure and the duration of hypertension, and here, IT (SMC greater than or equal to 3) showed no correlation. These data suggest that hyaline change and intimal thickening of small arteries and arterioles (SMC less than 3) are closely related to high blood pressure and that intimal thickening of small arteries rather than hyaline change causes renoparenchymal damage through ischemia and leads to a deterioration of renal function, in those with a benign nephrosclerosis.