In man prosthetic vascular grafts fail to develop an endothelial lining, no matter how long they have been implanted for. As a result, these grafts remain permanently thrombogenic and have poorer patency rates than grafts constructed using autologous vessels. Attempts have been made to artificially place endothelial cells on prosthetic grafts and this is termed “endothelial seeding”. The aim has been to produce an antithrombogenic surface similar to that possessed by normal vessels. In addition there have been attempts to produce artificial biological grafts or grafts lined with genetically modified cells. This approach of combining prosthetic materials and biologically active cells is usually referred to as “tissue-engineering”. Graft seeding and tissue-engineered grafts have shown definite advantages in animal studies as well as in some of the clinical trials, and are worthy of further study. Unfortunately they cannot, currently be recommended for routine clinical use. However, if the techniques could be successfully transferred to the clinical situation, they would represent a real advance in vascular surgery. Present research is directed to developing methods of accelerating endothelialization by pharmacological means, to enhance fallout of endothelial cell progenitors and the use of endothelial cells genetically engineered in order to make them produce more of desirable substances such as tissue plasminogen activator or growth factors to stimulate angiogenesis.
Keywords: seeding, endothelial cells, antithrombogenic, grafts postimplantation
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