Organ transplantation is a medical procedure in which an organ is removed from one body and placed in the body of a recipient, to replace a damaged or missing organ. The donor and recipient may be at the same location, or organs may be transported from a donor site to another location. Organs and/or tissues that are transplanted within the same person's body are called autografts. Transplants that are recently performed between two subjects of the same species are called allografts. Allografts can either be from a living or cadaveric source.
Hematopoietic stem-cell transplantation (HSCT) is the transplantation of multipotent hematopoietic stem cells, usually derived from bone marrow, peripheral blood, or umbilical cord blood, in order to replicate inside a patient and produce additional normal blood cells. HSCT may be autologous, syngeneic, or allogeneic.
Graft-versus-host disease (GvHD) is a syndrome, characterized by inflammation in different organs. GvHD is commonly associated with bone marrow transplants and stem cell transplants.
Skin grafting, a type of graft surgery, involves the transplantation of skin. The transplanted tissue is called a skin graft.
Grafting refers to a surgical procedure to move tissue from one site to another on the body, or from another creature, without bringing its own blood supply with it. Instead, a new blood supply grows in after it is placed. A similar technique where tissue is transferred with the blood supply intact is called a flap. In some instances, a graft can be an artificially manufactured device. Examples of this are a tube to carry blood flow across a defect or from an artery to a vein for use in hemodialysis.
Xenotransplantation, or heterologous transplant, is the transplantation of living cells, tissues or organs from one species to another. Such cells, tissues or organs are called xenografts or xenotransplants. It is contrasted with allotransplantation, syngeneic transplantation or isotransplantation and autotransplantation. Xenotransplantation is an artificial method of creating an animal-human chimera, that is, a human with a subset of animal cells. In contrast, an individual where each cell contains genetic material from a human and an animal is called a human–animal hybrid.
Cell therapy is a therapy in which viable cells are injected, grafted or implanted into a patient in order to effectuate a medicinal effect, for example, by transplanting T-cells capable of fighting cancer cells via cell-mediated immunity in the course of immunotherapy, or grafting stem cells to regenerate diseased tissues.
Bone grafting is a surgical procedure that replaces missing bone in order to repair bone fractures that are extremely complex, pose a significant health risk to the patient, or fail to heal properly. Some small or acute fractures can be cured without bone grafting, but the risk is greater for large fractures like compound fractures.
Arthrodesis, also known as artificial ankylosis or syndesis, is the artificial induction of joint ossification between two bones by surgery. This is done to relieve intractable pain in a joint which cannot be managed by pain medication, splints, or other normally indicated treatments. The typical causes of such pain are fractures which disrupt the joint, severe sprains, and arthritis. It is most commonly performed on joints in the spine, hand, ankle, and foot. Historically, knee and hip arthrodeses were also performed as pain-relieving procedures, but with the great successes achieved in hip and knee arthroplasty, arthrodesis of these large joints has fallen out of favour as a primary procedure, and now is only used as a procedure of last resort in some failed arthroplasties.
Autotransplantation is the transplantation of organs, tissues, or even particular proteins from one part of the body to another in the same person.
The word "syngenic" or "syngeneic" means genetically identical, or sufficiently identical and immunologically compatible as to allow for transplantation. For example, it may be used for something transplanted from an identical twin. When the cells are collected from the same patient on whom they will be used, a graft is called autologous. Syngeneic refers to a graft transferred between genetically identical animals or people. A syngeneic graft is known as an isograft.
Minor histocompatibility antigen are peptides presented on the cellular surface of donated organs that are known to give an immunological response in some organ transplants. They cause problems of rejection less frequently than those of the major histocompatibility complex (MHC). Minor histocompatibility antigens (MiHAs) are diverse, short segments of proteins and are referred to as peptides. These peptides are normally around 9-12 amino acids in length and are bound to both the major histocompatibility complex (MHC) class I and class II proteins. Peptide sequences can differ among individuals and these differences arise from SNPs in the coding region of genes, gene deletions, frameshift mutations, or insertions. About a third of the characterized MiHAs come from the Y chromosome. Prior to becoming a short peptide sequence, the proteins expressed by these polymorphic or diverse genes need to be digested in the proteasome into shorter peptides. These endogenous or self peptides are then transported into the endoplasmic reticulum with a peptide transporter pump called TAP where they encounter and bind to the MHC class I molecule. This contrasts with MHC class II molecules's antigens which are peptides derived from phagocytosis/endocytosis and molecular degradation of non-self entities' proteins, usually by antigen-presenting cells. MiHA antigens are either ubiquitously expressed in most tissue like skin and intestines or restrictively expressed in the immune cells.
An Isograft is a graft of tissue between two individuals who are genetically identical. Transplant rejection between two such individuals virtually never occurs, making isografts particularly relevant to organ transplantations; patients with organs from their identical twins are incredibly likely to receive the organs favorably and survive. Monozygotic twins have the same major histocompatibility complex, leading to the low instances of tissue rejection by the adaptive immune system. Furthermore, there is virtually no incidence of graft-versus-host disease.
Articular cartilage repair treatment involves the repair of the surface of the articular joint's hyaline cartilage, though these solutions do not perfectly restore the articular cartilage. These treatments have been shown to have positive results for patients who have articular cartilage damage. They can provide some measure of pain relief, while slowing down the accumulation of damage, or delaying the need for joint replacement surgery.
Transplantable organs and tissues may refer to both organs and tissues that are relatively often transplanted, as well as organs and tissues which are relatively seldom transplanted. In addition to this it may also refer to possible-transplants which are still in the experimental stage.
Demineralized bone matrix (DBM) is allograft bone that has had the inorganic mineral removed, leaving behind the organic "collagen" matrix. It was first discovered by Marshall Urist in 1965 that the removal of the bone mineral exposes more biologically active bone morphogenetic proteins. These growth factors modulate the differentiation of progenitor cells into osteoprogenitor cells, which are responsible for bone and cartilage formation. As a result of the demineralization process, DBM is more biologically active than undemineralized bone grafts; conversely the mechanical properties are significantly diminished.
TK is an experimental cell therapy which may be used to treat high-risk leukemia. It is currently undergoing a Phase III clinical trial to determine efficacy and clinical usefulness.
Nerve allotransplantation is the transplantation of a nerve to a receiver from a donor of the same species. For example, nerve tissue is transplanted from one person to another. Allotransplantation is a commonly used type of transplantation of which nerve repair is one specific aspect.
Shimon Slavin is an Israeli professor of medicine. He pioneered immunotherapy mediated by allogeneic donor lymphocytes and innovative methods for stem cell transplantation to cure hematological malignancies and solid tumors. He also used hematopoietic stem cells to induce transplantation tolerance to bone marrow and organ allografts.
Tissue transplantation is a surgical procedure involving the removal of tissue from a donor site or the creation of new tissue, followed by tissue transfer to the recipient site. The aim of tissue transplantation is to repair or replace tissues that are missing, damaged, or diseased, thereby improving patients' survival, functionality and quality of life.
