Genetic engineering of endothelial cells to ameliorate xenograft rejection.

The prospect of clinical xenotransplantation using pigs as donors (a discordant combination) holds out a potential solution to the shortage of human organs, as well as potentially widening the spectrum of patients who might benefit from a transplant procedure. While generalized clinical trials of pig to human organ transplantation (of immediately vascularized organs, such as the heart or kidney) will probably not occur in the very near future, there are reasons for optimism that this approach, deemed impossible a few decades ago, may find its way to the bedside. This optimism is based on two factors: First, a great increase in our understanding of the probable underlying causes of rejection and, second, the development of a number of important therapeutic approaches, including genetic manipulation of the donor animal, to tackle the manifold problems inherent in rejection of such a transplanted organ.