Investigation about origin and spreading of neoendothelium in autologous arterial vessel replacement

INTRODUCTION: In many fields of surgery an autologous arterial vessel replacement is used. Because of trauma and insufficient nutrition, a loss of complete endothelium in the replaced vessel segment and at the anastomoses can be observed within a few hours. The origin and the spread of the neoendothelium are unknown. Our study uses Von-Willebrand-protein, a product of endothelium cells, as a marker to obtain new information about the origin and spread of the new endothelial cells.

MATERIALS AND METHODS: Seventy Wistar rats, seven groups of 10 animals each, were operated. A four-millimetre-long segment of the common carotid artery was isolated and reinserted. After a varying length of time (between directly after the operation and six months after), the common carotid artery including bifurcation was isolated after cardioperfusion. Carotid arteries were embedded and cross-sections were stained with hematoxylineosin, Verhoeff's tissue elastin stain and immunohistochemical anti-Von-Willebrand-factor-antibody. The complete vessel was divided into nine points of measurement on each side, three points at each anastomosis and three points in transplanted segment. There the number of positive endothelial cells was rated.

RESULTS: Twenty-four hours after the operation no further endothelium was detectable in autologous transplant. Stainings eight days after operation contained Von-Willebrand-factor-positive cells in luminal cell layers. Near to the anastomosis excessive myointimal hyperplasia was detectable. Also, eight days after operation, some positive endothelial cells in adventitia were seen near to the anastomosis in small vessel lumina. Four weeks after operation, the luminal endothelium was completely regenerated and the luminal endothelial layer was confluent. Eight days after the operation regeneration in lateral regions was faster than in the region of the transplant.

CONCLUSION: In our experiment regeneration in lateral regions was faster than in the region of the transplant. Early staining in adventitia and proof of newly formed vasa vasora in adventitia may be a sign of a possible migration from adventitia to luminal area.