There is progressive need in small diameter (≤ 6mm) vascular prostheses caused by increased number of peripheral arteries' pathology worldwide and coronary arteries diseases as well. Commonly used autological vessels are considerably limited and have some serious short-comings including traumaticity of their deriving, increased infections and inflammatory complications. One of the most perspective alternatives of autovessels is using biological prostheses based on xenogeneic arteries. However the technologies of their treatment to reduce immunogenicity and prevent early occlusion have been uneffective till now.
The research aim. The goal of our study was to devitalize the xenogeneic arteries by using two physical factors: low temperatures and electron beam irradiation to create non-immunogenic biological vascular prostheses.Methods
The research objects were porcine intrathoracic arteries, derived from mature animals with meeting all the bioethical rules. Isolated vessels were deeply frozen and after thawing on water bath they were subjected to ionizing irradiation in the experimental doses. Morphological structure of devitalized arteries was estimated by optical and electron microscopies. Biomechanical properties of treated arteries were also estimated. Immunogenicity and biocompatibility of devitalized arteries were studied in vivo at subcutaneous xenoimplantation. Experimental vascular surgeries of xenoprosthetic repair have been also done with using devitalized arteries as vascular grafts.Results
Freezing led to initial damages of cells which were mainly noted in endothelial layer as desquamation areas. The following ionizing irradiation resulted in a complete deendothelization and significant destruction of smooth muscle cells. However the connective tissue structure of devitalized arteries was mainly preserved and internal elastic membrane has no considerable structural disorders. Combined influence of freezing and ionizing irradiation increased strength parameters of arteries. Xenoimplantation demonstrated the absence of any rejections on the devitalized arteries for all the observation terms. Performed experimental vascular surgeries have shown adequate functioning and high-grade patency of the treated arteries for 10 months at least, there were no signs of occlusion and inflammation reactions.Conclusion
The proposed treatment allows to design integrally functioning biological vascular grafts basing on xenogeneic arteries. Positive results of experimental transplantation testify that devitalized arteries are promising to be studied in clinic as biological vascular grafts.