Cytokeratin-positive and cytokeratin-negative cultured endothelial cells from bovine aorta and vena cava.

The heterogeneous morphology of microvascular endothelial cells obtained from the bovine corpus luteum was recently attributed to the occurrence of cytokeratin (CK) positive and CK negative endothelial cells. The aim of the present study was to establish comparable differences for bovine macrovascular endothelial cells. For this reason, endothelial cells were scraped from the abdominal aorta as well as the inferior vena cava of cows. At the level of phase contrast microscopy, primary cultures originating from both large vessels could be classified as CK positive or CK negative endothelial cells. After seeding CK positive endothelial cells on Matrigel matrix, a two-dimensional meshwork of so called pseudotubules formed within 2 h. By using immunofluorescence localization CK positive cells were identified by a complex meshwork. It consisted of CK 8, 18 and 19 as displayed by Western blots. The CK negative group showed spindle-shaped or polygonal endothelial cells according to light microscopy. In postconfluent cultures, spindle-shaped cells developed a three-dimensional meshwork of tubules. After seeding spindle-shaped cells on Vitrogen 100 matrix, pseudotubules formed within 1 day. In considering the frequency of occurrence, primary harvests from the vena cava contained less than 1% CK positive cells. With respect to growth, the cell number was two to three times higher for the CK negative group than the CK positive group as judged on day 13 after cell seeding. It is concluded that subpopulations of endothelial cells are derived from large blood vessels.