Monocytogenic endothelialization in dacron grafts. Experimental studies on rats

The cytogenetic relationship between cells of the hematopoetic system and prosthesis lining cells is still not known. The purpose of this experimental study was to determine to what degree blood monocytes may be transformed into those cells which line the inner surface of vascular grafts. Immunological identical rats (donors = 25) were pretreated with a total dose of 150 micrograms C 3H-thymidine. In 25 recipient rats of the same strain the infrarenal aorta had been replaced by a vascular graft of dacron (1.8 mm theta) by using microsurgical techniques. Arteriovenous cross-transfusion was installed in pairs of the donor and recipient animals allowing for mixing the total blood volumes of both many times. Following sacrifice of the recipients the grafts and the area of anastomosis were studied autoradiographically. In all animals labelled monocytes were found in the graft wall with a marking index (MI) running between 1.5% to 5.5%. The marking index of the prosthesis lining cells was 1.9% to 3.4%. In 6 animals the anastomotic area was labelled and the MI run from 1% to 7.5%. With this new experimental model we ascertained that blood monocytes have capability of transformation: our results would indicate the hematogenic origin of new endothelial cells on prosthetic vascular surface by transformation of blood monocytes. This appears to apply to the prosthetic wall as well as the inner surface lining cells and the neighbourhood of the anastomotic area.