Food restriction prevents advanced glycation end product accumulation and retards kidney aging in lean rats

Abstract

Tissue content of advanced glycation end products (AGE) increases with age and contributes to the changes in structure and function of the renal and cardiovascular systems. The effect of chronic food restriction on this AGE accumulation was investigated in lean WAG/Rij rats. A 30% food restriction performed from 10 to 30 mo in female rats reduced their mean body weight from 240 ± 7 to 160 ± 12 g, but did not modify their survival. AGE collagen content increased from 14.3 ± 5.5 to 104.7 ± 13.0 arbitrary units per microgram (AU/μg) of hydroxyproline (OHPro) in kidney between 10 and 30 mo, and from 9.7 ± 1.2 to 310.6 ± 34.6 AU/μg OHPro in the abdominal aorta. Food restriction reduced AGE accumulation to 21.4 ± 3.3 and 74.6 ± 16.5 AU/μg OHPro in kidney and aorta of 30-mo-old animals. Similar results were found for collagen prepared from isolated glomeruli (7.8 ± 1.2, 81.2 ± 16.1, and 10.3 ± 4.3 AU/μg OHPro in 10-mo, 30-mo, and restricted 30-mo-old rats). Reduction of intrarenal and arterial AGE accumulation by food restriction was confirmed by immunostaining in optical microscopy. Age- related changes in arterial and kidney structures as polyuria and proteinuria were mainly prevented by food restriction. These data indicate that chronic food restriction reduces the accumulation of AGE and preserves the structure and function of the renal and cardiovascular systems in lean rats, although it did not affect survival of the animals between 10 and 30 mo.