Essay On Xenotransplantation

Beneficence and risk-to-benefit analysis

Ethical issues also play a role in the selection of the solutions. Most patients perceive xenotransplantation as an acceptable alternative to transplantation of human organs in life-threatening situations provided the potential benefits outweigh any likely adverse effects on the animals. Xenotransplantation of organs from chimpanzees and baboons has been avoided, because of ethical concerns as chimpanzees are listed as endangered species and the fear of transmission of deadly viruses. Pigs are plentiful, quick to mature, breed well in captivity, have large litters, and have vital organs roughly comparable in size to those of humans. Further there are physiologic similarities between their antibodies to human antibodies, and also since they are already being used in the consumer market, organs have been mainly harvested from pigs. Humans have had prolonged and close contact with pigs, their use for the purpose of xenotransplantation is believed to be less likely to introduce any new infectious agents. Porcine islet cells of Langerhans have been injected into patients with type 1 diabetes mellitus. Porcine skin has been grafted onto burn patients, and pig neuronal cells have been transplanted into patients with Parkinson’s disease and Huntington’s disease.

However, use of pig xenografts is associated with major immunologic barriers, resulting in Hyper Acute Rejection (HAR) or Acute Vascular Rejection (AVR) when transplanted into a human recipient as humans have naturally occurring antibodies against pig cells. To resolve this issue genetically engineered pigs have been designed to reduce the expression of various immunogenic substances. Further the graft is given a break from attack when ci...

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... date. By contrast, the transplantation of baboon livers and chimpanzee kidneys into humans had resulted in deaths due to illnesses not related to organ failure.

But at the same time it is not possible to apply this result / estimation to all procedures as the precise risk will vary from one procedure to another, depending on a range of factors which need to be observed over a long term. The US Public Health Service agencies (i.e., FDA, Centers for Disease Control and Prevention, National Institutes of Health, and Healthcare Resource Services Administration) and the Office of the Associate Secretary for Planning and Evaluation of the Department of Health and Human Services are collaborating to develop an integrated approach to be applied at societal, institutional, and individual (patient-physician) levels to address infectious disease issues in Xenotransplantation.