Regional differences in the replication rate of cultured rat microvascular endothelium from retroperitoneal and epididymal fat pads.

Study of the vascular endothelium has been greatly facilitated by the development of specific cell culture systems isolated from various tissues. We report herein a simple method for establishing a propagating cell culture system of microvascular endothelial cells derived from rat adipose tissue. In addition to the characteristic cobblestone appearance on light microscopy, the microvascular endothelial cells in culture also demonstrated the presence of other markers for large vessel endothelia. Electron microscopy revealed endothelium-specific Weibel-Palade bodies and abundant pinocytotic vesicles. Both retroperitoneal and epididymal endothelia demonstrated the presence of factor VIII antigen by immunofluorescent staining and prostacyclin production. Although there was no appreciable morphological difference between cultured retroperitoneal and epididymal microvascular endothelia, the replication rate of the former was significantly higher than that of the latter (P less than .05). Excessive replication of endothelial cells may play a role in the regional differences of adipose tissue mass in an organism.