Glomerular Basement Membrane in Diabetics

Abstract

In 30 needle renal biopsies and 2 autopsies of diabetic patients, light and electron microscopy studies revealed that: the mean width of peripheral basement membrane ranged from 1791 to 7723 A per case, and the standard deviation ranged from 504 to 2080; the mean width of peripheral basement membrane of all glomeruli, ranged from 1791 to 8780 A, based on 7140 measurements, and the standard deviation ranged from 504 to 2990; a separation of cases with nodules from those without nodules showed a mean width of basement membrane of 5373 A in glomeruli with nodules, and a standard deviation of 2280; the mean width in glomeruli without nodules was 3293 A, the standard deviation 1260. It was concluded that the mean width of the basement membranes of glomeruli in diabetics was within the range of normal but was abnormally thick in 5 of 7 cases with nodules. In 2 cases with nodules, the peripheral basement membrane was within the range of normal. These data do not confirm the statements that all diabetics have thickened glomerular peripheral basement membranes or that thickening occurred prior to the development of intercapillary nodules. The generally accepted concept of invariable and early thickening of peripheral basement membrane is based upon observations of irregular focal increase of width which can not be quantitated and compared with the normal variation of thickness. Comparable values can be obtained only if the measurements exclude portions of basement membrane covering the mesangium and if a statistically significant number of measurements is taken. As in the normal glomeruli, mesangial periodic acid-Schiff-positive deposits roughly parallel peripheral basement membrane thickness in glomeruli of diabetics. Arterio- and arteriolosclerosis can not be related to either mesangial deposits or basement membrane thickness.