The effect of aging on microvascular density and angiogenesis (665.4)

Abstract

Age related pathologies are commonly associated with vessel loss or excess vessel growth. An important question is whether or not angiogenesis, defined as the growth of new vessels from existing ones, is altered during aging. Angiogenesis in aged populations is commonly thought to be impaired. However, much of this supporting evidence is based on local changes in angio‐regulator molecules. The objective of this study was to quantitatively compare microvascular network remodeling metrics during angiogenesis in adult versus aged rat strains. Mesenteric tissues from adult (9 months) and aged (24 months) male Fischer 344 rats were harvested according to 4 experimental groups: 1) Adult Unstimulated (n=4 rats, 16 tissues), 2) Aged Unstimulated (n=4 rats, 16 tissues), 3) Adult Stimulated (n=4 rats, 16 tissues), 4) Aged Stimulated (n=4 rats, 16 tissues). For stimulated groups, tissues were harvested 3 days post compound 48/80‐induced mast cell degranulation stimulation. Unstimulated aged microvascular networks displayed larger mean vascular area per tissue area compared to the unstimulated adult networks. Following angiogenic stimulation, both adult and aged networks displayed similar increases in vascularized area and vessel length density compared to their respective unstimulated control groups, indicating that both adult and aged networks are capable of undergoing angiogenesis. However, capillary sprouting was significantly lower in stimulated aged networks compared with stimulated adult networks, supporting the hypothesis of impaired angiogenesis during aging. Interestingly, our results provide metric specific evidence for both comparable and impaired angiogenesis during aging and offer a possible explanation for conflicting results from the literature.Grant Funding Source: Supported by Tulane Center for Aging and NIH 5‐P20GM103629‐02