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Allotransplantation

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Not to be confused with Allogenic succession.
Allotransplants
MeSHD014184

Allotransplant (allo- from the Greek meaning "other") is the transplantation of cells, tissues, or organs, to a recipient from a genetically non-identical donor of the same species.[1] The transplant is called an allograft, allogeneic transplant, or homograft. Most human tissue and organ transplants are allografts. A xenograft is a graft from a different species, such as when animal tissue is grafted into human tissue, or when human cancer cells are implanted in mice for experimental tumor studies. Allografts can be referred to as "homostatic" if they are biologically inert when transplanted, such as bone and cartilage.[2]

An immune response against an allograft or xenograft is termed rejection. An allogenic bone marrow transplant can result in an immune attack, called Graft-versus-host disease.

Procedure

Informed consent is required before tissue is harvested from a donor, alive or dead. Proper screening for pathology and risk factors for communicable diseases such as HIV and Hepatitis B and C is then conducted.

In the US, donor tissue must be harvested and processed adhering to the Current Good Tissue Practices rule. In most cases it is sent to tissue banks for processing and distribution. Each year, Food and Drug Administration regulated and American Association of Tissue Banks-accredited tissue banks distribute 1.5 million bone and tissue allografts.

Transplantable organs and tissues

Main article: Transplantable organs and tissues

A variety of organs and tissues can be used for allografts, including:

Laws and regulations

In the US, the Federal government Food and Drug Administration (FDA) has regulated human tissue intended for transplants since 1993. In order to ensure the quality of donor tissue and reduce contamination and disease transmission risks, three regulations addressing manufacturing activities associated with human cells, tissues, and cellular and tissue-based products (HCT/Ps) were promulgated in May 2005: The first requires companies producing and distributing HCT/Ps to register with the FDA. The second, called the “Donor Eligibility” rule, proscribes criteria for donor eligibility. The third, the “Current Good Tissue Practices” rule, oversees overall processing and distribution practices of each company.

Other transplant options

  • Autograft, tissue transplanted from one site to another on the same patient. An autograft reduces the risk of rejection but requires a second surgery site, adding pain, risk and possible longer aftercare.
  • Xenograft, a transplant from another species
  • Isograft, a transplant from a genetically identical donor, such as an identical twin.
  • Synthetic and metal implants. Unlike allografts, such grafts do not corporate into the body.

Risks

Tissue transplantation is the basis of most if not all modern plastic and reconstructive surgery. Composite tissue allotransplantation has recently emerged as a new way to reconstruct the tissue in our bodies where we lack them. As with many operations, allotransplantation also has some side effects. A limiting factor in tissue allotransplantation for reconstructive surgery deals with the side effects of immunosuppression (metabolic disorders, malignancies, opportunistic infections) which is a predominant issue. The matching a donor and recipient under the cosmetic criteria (gender, age, ethnic background) is limited and complicated by the lack of organ and tissue donors across the world. Also it can not be forgotten that the the risk of transmitting infection is very high. Currently research is still being done and the risks and side effects are still being studied. Allotransplantation is still fairly new so much research has not been found and so it is changing and being updated (4). .[3]

Future of Allotransplantation

Future of Allotransplantation The future of allotransplantation is changing and evolving. Operations have shown that transplantation is technically feasible, with the survival of a graft depending highly on a high level of indefinite immunosuppression. The nature of transplantation is constantly changing and improving how tissue reconstruction works.

Experimental research in transplantation is rapidly evolving. Soon, new molecules will expand the range of immunosuppressive agents, reduce the toxic level of current drugs, and might even prevent the cut of chronic rejection. While in the long term, tolerance induction through a preconditioning procedure of the recipient offers great promise by dodging indefinite immunosuppression (5).

Overall allotransplantion offers a great way for reconstruction surgery. Allotransplantation may not be the the solution for all defects there is but can greatly enhance reconstructive options for patients. It is currently restricted to people major disability conditions and must be performed with strict medical and ethical standards (6).

See also

References

Template:Research help

  1. ^ Surgery For ACL Tears
  2. ^ (W. P. Longmire, J. National Cancer Institute 14, 669: The term homostatic graft might be applied to inert tissues such as bone and cartilage when transferred from one individual to another of the same species; and the term homovital graft might be used in reference to grafts whose cells must continue to grow and reproduce for the graft to be effective after similar transplantation; H. Conway, The Bulletin of the Hong Kong Chinese Medical Association 13, 43: These grafts persist however as homostatic grafts and are completely replaced by host tissues in time.)
  3. ^ "Composite Tissue Allotransplantation and Reconstructive Surgery". US National Library of Medincine.
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