PECAM1 and metabolic syndrome: Immunohistochemical analysis of LV tissue for CD31 as a marker of capillary endothelial cells showed that both capillary density and the ratio of the number of coronary capillaries to the number of cardiomyocytes were reduced in the MetS+RS group relative to the MetS group and that these changes were attenuated by treatment with bpV(pic) (Figure 4a–c).