DECREASED GLOMERULOSCLEROSIS IN AGING BY ANGIOTENSIN-CONVERTING ENZYME-INHIBITORS

To evaluate the effects of angiotensin-converting enzyme inhibition on renal aging, enalapril was administered in the drinking water to thre e groups of CF1 mice at doses of 20 mg/L (Group A), 10 mg/L (Group B), and 5 mg/L (Group C). These experimental groups were compared with 20 CF1 mice not receiving enalapril (Group D). At 2 yr, total body weigh t was 48.1 +/- 7.5 g in Group A, 47.7 +/- 7.1 g in Group B, 47.6 +/- 4 .6 g in Group C, and 35.1 +/- 5.4 g in Group D. The ratio of kidney to total body weight, in percentages, was 1.8 +/- 0.3, 1.6 +/- 0.3, 1.9 +/- 0.2, and 1.5 +/- 0.1 in Groups A, B, C, and D, respectively. Morph ometric studies of the kidneys revealed the glomerular diameter to be 86.7 +/- 18.0 mu m, 96.9 +/- 6.3 mu m, 91.1 +/- 11.4 mu m, and 106.8 /- 9.3 mu m in Groups A, B, C, and D, respectively. The number of glom eruli per square millimeter of renal cortex was 9.6 +/- 3.7, 12.3 +/- 2.7, 12.4 +/- 8.6, and 3.2 +/- 1.5 in Groups A, B, C, and D, respectiv ely. The mesangial area per glomerulus, in percentages, was 11.6 +/- 4 .8, 13.9 +/- 2.9, 14.2 +/- 3.1, and 20.6 +/- 1.9 in Groups A, B, C, an d D, respectively. The percentage of glomeruli with sclerosis was 0.1 +/- 0.1, 0.3 +/- 0.1, 0.6 +/- 0.2, and 11.6 +/- 1.9 in Groups A, B, C, and D, respectively. For all of the measurements described, the P val ue was less than 0.01 comparing groups A, B, or C with D. There were n o significant differences in blood pressure between treated and contro l groups. These data suggest that angiotensin-converting enzyme inhibi tion decreases the renal and glomerular changes that normally accompan y the aging in CF1 mice.