Resistance Vessel Endothelium: Isolation, Cloning and Characterization Studies
Vascular endothelial cells are not homogeneous throughout the body but have unique functional properties depending upon organ and species. Considerable evidence also suggests functional differences between endothelial cells derived from micro and macrovascular origin. In this report, we have successfully isolated and characterized endothelial cells derived from enriched preparations of rat cerebral resistance vessels. Previous work from our laboratory demonstrated that cerebromicrovascular smooth muscle cells derived from resistance vessels grew at a slower rate when compared to large vessel (aorta) derived smooth muscle cells and failed to tolerate standard freezing procedures at low passage levels (J. Cell Physiol.129:131,1986). Using collagenase dissociation, we were able to significantly enhance the presence of resistance vessel endothelial cells. Once established and cloned, these cultures express Factor VIII antigen and exhibit phenotypic characteristics of cultured endothelial cells. In addition, these cells, under normal culture conditions, spontaneously form “tube-like” arrays. The presence of the mas oncogene (putative All receptor) mRNA was found in subconfluent and confluent resistance vessel endothelial cell cultures using a probe (pRM I) that contains the gene for the rat mas oncogene. These results demonstrate that resistance vessel derived endothelial cells can easily be isolated and subcultured to provide an in vitro cell system to study cerebral angiogenesis. In addition, the availability of both smooth muscle and endothelial cell population from the same microvascular source will provide a unique system to study their cell-cell interactions in vitro.