• Another Glossary is provided at the end of the document entitled Scientific Issues Raised by Xenotransplantation.

Allotransplant: An organ or tissue transplanted between two members of the same species, such as two humans.

Biological incompatibility: The differences in tissues between species that makes xenotransplantation extremely difficult. This incompatibility is least severe between humans and other primates, and increases as species become more different.

Biotechnology: The use of biological techniques to develop new products used in medicine and industry. These techniques often involve altering genes or transferring genes from one species to another.

Clinical trials: Tests on informed and consulting volunteers. Health Canada will permit clinical trials only if they are deemed safe and will prove something medically worthwhile. Proposed trials also require approval from independent ethics boards at the hospital or research facility where the work is to proceed.

Clone: An exact genetic copy of an existing animal or plant.

Diabetes: Caused primarily by the destruction of islet cells that produce insulin in human bodies. Pre-clinical research is now exploring the possibility of pig islets transplanted into a patient to control blood sugar levels.

Genetic engineering: A way of directly manipulating genetic material in a cell or organism to produce desired traits. Animals can be bred to contain human genes so that the animal cells will be more readily accepted by a patient’s immune system. Genetically- engineered animals are called transgenic animals.

Immunosuppression: The prevention of or interference with an immune response, either by disease or drugs. After receiving an organ transplant, a patient must be immunosuppressed by drugs to prevent the body from rejecting the organ.

Parkinson’s disease: A common crippling disease characterized by muscle spasms and rigidity, tremors, slow movements and loss of control over many parts of the body. It is caused by a dopamine deficiency that prevents certain brain cells from performing their normal duties.

Pathogen: An organism that causes disease, such as a virus or bacteria.

PERV: A pig virus known as porcine endogenous retrovirus that is found in the genetic material of every pig. PERVs cannot be eliminated or screened out and laboratory experiments have shown that they can infect human cells. It is not known if PERVs can be transmitted through a xenotransplant.

Protocol: A precise and detailed plan for the study of a biomedical problem or for the treatment of a medical condition.

Rejection: An immune reaction a patient may have against an organ or tissue that has been transplanted.

Retrovirus: A particular type of virus that contains only RNA, which allows its genetic material to become part of its hosts’ DNA (an extremely long molecule that carries a cell’s genetic information). This enables the virus to be carried into the host’s future generations. AIDS is a retrovirus.

Standards-based regulation: Means that every practice associated with xenotransplantation would have to meet or exceed clearly defined standards under federal law. For example, standards could define how animals should be raised, how tissues must be handled, how surgeons are to be accredited and what information must be registered in a databank.

Tissue engineering: A way of building new tissue by replicating cells.

Transgenic animal: An animal deliberately produced to carry a gene from another animal.

Xenotransplantation: The term usually meant to describe the transfer of living cells, tissues and organs from non-human animals into humans for medical purposes.

Zoonoses: Animal diseases that can be transmitted to humans under natural conditions. Both animals and humans are affected by zoonoses, which include rabies, brucellosis and mad cow disease (Creutzfeldt-Jakob disease in humans). Xenozoonoses are zoonoses specifically transmitted by xenotransplantation.