It is estimated that about 100,000 patients annually need xenografts. The potential market for this new industry is projected to be in the billions of dollars.
Xenotransplantation has many potential advantages over allogenic transplantation.
Organs from animals are readily available and often show resistance to viruses and other infectious agents to which humans are susceptible. For instance, pig livers have been used as ex-vivo supports for liver failure patients, through the expression of human genes in transgenic pig cells and tissues to prevent hyperacute rejection. Other examples include the transplantation of pig fetal tissue into patients with Parkinson's disease, and pig pancreatic islet cells into patients with diabetes. The market for porcine tissues in liver failure, diabetes mellitus, and degenerative neurologic diseases is increasing substantially. Accordingly, it is well recognized that all xenotransplanted tissue needs to be thoroughly evaluated prior to use for the presence of any potentially infectious agents.