Decreased glomerulosclerosis in aging by angiotensin-converting enzyme inhibitors

Abstract

To evaluate the effects of angiotensin-converting enzyme inhibition on renal aging, enalapril was administered in the drinking water to three 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 weight 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. Morphometric studies of the kidneys revealed the glomerular diameter to be 86.7 ± 18.0 μm, 96.9 ± 6.3 μm, 91.1 ± 11.4 μm, and 106.8 ± 9.3 μm in Groups A, B, C, and D, respectively. The number of glomeruli 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, respectively. 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, and 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 value was less than 0.01 comparing groups A, B, or C with D. There were no significant differences in blood pressure between treated and control groups. These data suggest that angiotensin-converting enzyme inhibition decreases the renal and glomerular changes that normally accompany the aging in CF1 mice.