BackgroundAging exponentially increases the incidence of morbidity and mortality of quintessential cardiovascular disease mainly due to arterial proinflammatory shifts at the molecular, cellular, and tissue levels within the arterial wall. Calorie restriction (CR) in rats improves arterial function and extends both health span and life span. How CR affects the proinflammatory landscape of molecular, cellular, and tissue phenotypic shifts within the arterial wall in rats, however, remains to be elucidated.Methods and ResultsAortae were harvested from young (6âmonthâold) and old (24âmonthâold) Fischer 344 rats, fed ad libitum and a second group maintained on a 40% CR beginning at 1 month of age. Histopathologic and morphometric analysis of the arterial wall demonstrated that CR markedly reduced ageâassociated intimal medial thickening, collagen deposition, and elastin fractionation/degradation within the arterial walls. Immunostaining/blotting showed that CR effectively prevented an ageâassociated increase in the density of plateletâderived growth factor, matrix metalloproteinase type II activity, and transforming growth factor beta 1 and its downstream signaling molecules, phosphoâmothers against decapentaplegic homologâ2/3 (pâSMADâ2/3) in the arterial wall. In early passage cultured vascular smooth muscle cells isolated from AL and CR rat aortae, CR alleviated the ageâassociated vascular smooth muscle cell phenotypic shifts, profibrogenic signaling, and migration/proliferation in response to plateletâderived growth factor.Conclusions
CR reduces matrix and cellular proinflammation associated with aging that occurs within the aortic wall and that are attributable to plateletâderived growth factor signaling. Thus, CR reduces the plateletâderived growth factorâassociated signaling cascade, contributing to the postponement of biological aging and preservation of a more youthful aortic wall phenotype.