Morphological Changes Underlying High Fat Diet‐Associated Arterial Stiffening Differ with Advancing Age

Abstract

Although it is not known how these risk factors interact, aging and obesity independently increase arterial stiffness and contribute to cardiovascular morbidity/mortality. We studied normal chow (NC) or high (40%) fat (HF) fed young (5–7mo) and old (28–31mo) male B6D2F1 mice to determine the effect of aging on obesity‐associated increases in arterial stiffness and morphology. Aortic stiffness, measured by pulse wave velocity (PWV), was greater in old compared to young (369±8 v 245±14 cm/s, P=0.04) NC fed mice and was concurrent with a ~3‐fold increase (P=0.015) in aortic collagen content (Picrosirius Red) and a ~50% reduction (P<0.05) in medial elastin (Van Gieson). In young mice, HF increased stiffness (359±18 cm/s, P<0.05) and was associated with increased collagen (59±9 v 19±8%, P=0.04) and reduced elastin (54±7 v 88±3%, P<0.05), similar to aging alone. Although aortic stiffness was higher in old mice after HF (385±47 cm/s, P=0.02) there was no effect on collagen content or medial elastin in old mice. In conclusion, age‐related arterial stiffening is associated with altered collagen and elastin content and, although HF feeding increases arterial stiffness across age, the associated morphological changes differ between young and old mice. Thus, the underlying mechanisms and effective therapeutic strategies used to combat obesity –associated arterial stiffness may differ with advancing age.AG040297, AG033755, AG033196