| Autotransplantation |
Autotransplantation is the transplantation of organs, tissues, or even particular proteins from one part of the body to another in the same person (auto- meaning "self" in Greek[1]).
The autologous tissue (also called autogenous, autogeneic, or autogenic tissue) transplanted by such a procedure is called an autograft or autotransplant.[2]
It is contrasted with allotransplantation (from other individual of the same species), syngeneic transplantation (grafts transplanted between two genetically identical individuals of the same species) and xenotransplantation (from other species).
A common example is the removal of a piece of bone (usually from the hip) and its being ground into a paste for the reconstruction of another portion of bone.
Autotransplantation, although most common with blood, bone, hematopoietic stem cells, or skin, can be used for a wide variety of organs. One of the rare examples is autotransplantation of a kidney from one side of the body to the other. Kidney autotransplantation is used as a treatment for nutcracker syndrome.[3]
See also: Intraoperative blood salvage. In blood banking terminology, autologous blood donation refers to a blood donation marked for use by the donor, typically for a scheduled surgery. (Generally, the notion of "donation" does not refer to giving to oneself, though in this context it has become somewhat acceptably idiomatic.) They are commonly called "autos" by blood bank personnel, and it is one major form of the more general concept of autotransfusion (the other being intraoperative blood salvage).
Some advantages of autologous blood donation are:
The disadvantages are:
Autologous blood is not routinely tested for infectious diseases markers such as HIV antibodies. In the United States, autologous blood is tested only if it is collected in one place and shipped to another.
There is also a risk that, in an emergency or if more blood is required than has been set aside in advance, the patient could still be exposed to donor blood instead of autologous blood. Autologous donation is also not suitable for patients who are medically unable to or advised not to give blood, such as cardiac patients or small children and infants.[5]
In orthopaedic medicine, a bone graft can be sourced from a patient's own bone in order to fill space and produce an osteogenic response in a bone defect. However, due to the donor-site morbidity associated with autograft, other methods such as bone allograft and bone morphogenetic proteins and synthetic graft materials are often used as alternatives. Autografts have long been considered the "Gold Standard" in oral surgery and implant dentistry because it offered the best regeneration results. Lately, the introduction of morphogen-enhanced bone graft substitutes have shown similar success rates and quality of regeneration; however, their price is still very high.
Autotransplantation of selected organs is often preceded by ex vivo (also bench, back-table, or extracorporeal) surgery.[6] For example, ex vivo liver resection and autotransplantation is used in the treatment of selected cases of conventionally unresectable hepatic tumors.[7] It can also be implemented in rare scenarios of a blunt abdominal trauma.[8] Kidney autotransplantation is a method of a nephron-sparing renal tumor excision or complex renal artery aneurysm management.[9] [10] The uses of ex vivo surgery followed by autotransplantation were reported also for heart, lungs and intestines, including multivisceral approaches.[6]
Induced pluripotent stem cells (iPSCs), capable of differentiating into any cell type, have potential for solving the problem of donor organ shortage. Reprogramming technology would be used to obtain a personalized, patient-specific, cell product without problems related to histocompatibility of the transplanted tissues and organs. However, the ability to generate such tissues and organs will depend on successful strategies to overcome immunogenicity of the manipulated product.[11]
Autologous stem-cell transplantation involves harvesting peripheral blood mononuclear cells (PBMCs) by apheresis collection following mobilization of stem cells from the bone marrow into the peripheral blood. This is typically used for treatment of multiple myeloma or aggressive lymphoma. Stem cells are cryopreserved after collection for infusion after the patient undergoes high-dose chemotherapy. Stem cell rescue permits the use of higher doses of chemotherapy than would be tolerated otherwise.[12]