Greek
Greek may refer to:
Anything of, from, or related to Greece, a country in Southern Europe:
*Greeks, an ethnic group
*Greek language, a branch of the Indo-European language family
**Proto-Greek language, the assumed last common ancestor of all kno ...
cells
Cell most often refers to:
* Cell (biology), the functional basic unit of life
* Cellphone, a phone connected to a cellular network
* Clandestine cell, a penetration-resistant form of a secret or outlawed organization
* Electrochemical cell, a d ...
organs
In a multicellular organism, an organ is a collection of tissues joined in a structural unit to serve a common function. In the hierarchy of life, an organ lies between tissue and an organ system. Tissues are formed from same type cells to a ...
to a recipient from a genetically non-identical donor of the same species. The transplant is called an allograft, allogeneic transplant, or homograft. Most human tissue and
organ transplant
Organ transplantation is a medical procedure in which an organ (anatomy), 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 org ...
s are allografts.
It is contrasted with
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).
The autologous tissue (also called autogenous, autogenei ...
(from one part of the body to another in the same person),
syngenic
The word "syngenic" or "syngeneic" (from the Greek word for a relative) means genetically identical, or sufficiently identical and immunologically compatible as to allow for transplantation. For example, it may be used for something transplanted fr ...
transplantation of isografts (grafts transplanted between two genetically identical individuals) and
xenotransplantation
Xenotransplantation (''xenos-'' from the Greek meaning "foreign" or strange), or heterologous transplant, is the transplantation of living cells, tissues or organs from one species to another.cartilage
Cartilage is a resilient and smooth type of connective tissue. Semi-transparent and non-porous, it is usually covered by a tough and fibrous membrane called perichondrium. In tetrapods, it covers and protects the ends of long bones at the joints ...
.(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.)''
An immune response against an allograft or
xenograft
Xenotransplantation (''xenos-'' from the Greek meaning "foreign" or strange), or heterologous transplant, is the transplantation of living cells, tissues or organs from one species to another.rejection. An allogenic bone marrow transplant can result in an immune attack on the recipient, called
graft-versus-host disease
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.
White blood cells of the donor's immune system which rema ...
.
Procedure
Material is obtained from a donor who is a living person, or a deceased person's body receiving mechanical support or ventilation, or a deceased person's body whose heart stopped beating. Screening for pathology and risk factors for communicable diseases such as
HIV
The human immunodeficiency viruses (HIV) are two species of '' Lentivirus'' (a subgroup of retrovirus) that infect humans. Over time, they cause acquired immunodeficiency syndrome (AIDS), a condition in which progressive failure of the im ...
and Hepatitis B and C is then conducted.
In the US, donor tissue must be recovered and processed adhering to the
Current Good Tissue Practices Good tissue practice (GTP) is one of the " GxP" requirements derived from good manufacturing practice. The rule was written and is enforced by the U.S. Food and Drug Administration (FDA), specifically the Center for Biologics Evaluation and Research ...
rule. In most cases, it is sent to tissue banks for processing and distribution. Each year,
Food and Drug Administration
The United States Food and Drug Administration (FDA or US FDA) is a List of United States federal agencies, federal agency of the United States Department of Health and Human Services, Department of Health and Human Services. The FDA is respo ...
regulated and
American Association of Tissue Banks The American Association of Tissue Banks (AATB) is a nonprofit transplant trade organization that is dedicated to ensuring that human tissues intended for transplantation are safe and free of infectious disease, of uniform high quality, and availa ...
-accredited tissue banks distribute 1.5 million bone and tissue allografts.
Transplantable organs and tissues
A variety of organs and tissues can be used for allografts, including:
*
Anterior cruciate ligament
The anterior cruciate ligament (ACL) is one of a pair of cruciate ligaments (the other being the posterior cruciate ligament) in the human knee. The two ligaments are called "cruciform" ligaments, as they are arranged in a crossed formation. In ...
(ACL) repair
* Joint reconstruction in the
knee
In humans and other primates, the knee joins the thigh with the leg and consists of two joints: one between the femur and tibia (tibiofemoral joint), and one between the femur and patella (patellofemoral joint). It is the largest joint in the hu ...
and
ankle
The ankle, the talocrural region or the jumping bone (informal) is the area where the foot and the leg meet. The ankle includes three joints: the ankle joint proper or talocrural joint, the subtalar joint, and the inferior tibiofibular joint. The ...
* Meniscal replacement
* Reconstruction due to cancer or trauma
* Ridge augmentation in dental procedures
* Shoulder repair
*
Spinal fusion
Spinal fusion, also called spondylodesis or spondylosyndesis, is a surgery performed by Orthopedic surgery#Practice, orthopaedic surgeons or neurosurgeons that joins two or more vertebrae. This procedure can be performed at any level in the spine ...
Skin
Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation.
Other animal coverings, such as the arthropod exoskeleton, have different ...
transplants
*
Cornea
The cornea is the transparency (optics), transparent front part of the eyeball which covers the Iris (anatomy), iris, pupil, and Anterior chamber of eyeball, anterior chamber. Along with the anterior chamber and Lens (anatomy), lens, the cornea ...
Heart valve
A heart valve is a biological one-way valve that allows blood to flow in one direction through the chambers of the heart. A mammalian heart usually has four valves. Together, the valves determine the direction of blood flow through the heart. Hea ...
s
* Lung transplantation
* Intestinal transplantation (isolated small bowel, intestine & liver, multivisceral)
* Liver transplants
*
Kidney transplants
Kidney transplant or renal transplant is the organ transplant of a kidney into a patient with end-stage kidney disease (ESRD). Kidney transplant is typically classified as deceased-donor (formerly known as cadaveric) or living-donor transplantati ...
*
Pancreas transplantation
A pancreas transplant is an organ transplant that involves implanting a healthy pancreas (one that can produce insulin) into a person who usually has diabetes.
Overview
Because the pancreas is a vital organ, performing functions necessary in the ...
*
Islet cell transplantation
Islet transplantation is the transplantation of isolated islets from a donor pancreas into another person. It is a treatment for type 1 diabetes. Once transplanted, the islets begin to produce insulin, actively regulating the level of glucose in ...
*
Bone marrow transplant
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 a ...
s
*
Bone
A bone is a rigid organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, ...
allograft
*
Ligament
A ligament is a type of fibrous connective tissue in the body that connects bones to other bones. It also connects flight feathers to bones, in dinosaurs and birds. All 30,000 species of amniotes (land animals with internal bones) have liga ...
or
tendon
A tendon or sinew is a tough band of fibrous connective tissue, dense fibrous connective tissue that connects skeletal muscle, muscle to bone. It sends the mechanical forces of muscle contraction to the skeletal system, while withstanding tensi ...
allograft
Laws and regulations
United States
In the US, the
Food and Drug Administration
The United States Food and Drug Administration (FDA or US FDA) is a List of United States federal agencies, federal agency of the United States Department of Health and Human Services, Department of Health and Human Services. The FDA is respo ...
(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:
* companies producing and distributing HCT/Ps must register with the FDA.
* "Donor Eligibility" rule: prescribes criteria for donor eligibility.
* "Current Good Tissue Practices" rule: oversees overall processing and distribution practices of each company.
Other transplant options
*
Autograft
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).
The autologous tissue (also called autogenous, autogen ...
, 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
Xenotransplantation (''xenos-'' from the Greek meaning "foreign" or strange), or heterologous transplant, is the transplantation of living cells, tissues or organs from one species to another.Isograft
An Isograft is a graft of tissue between two individuals who are genetically identical (i.e. monozygotic twins). Transplant rejection between two such individuals virtually never occurs, making isografts particularly relevant to organ transplan ...
, 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
As with many operations, allotransplantation risks some side effects. A limiting factor in tissue allotransplantation for reconstructive surgery deals with the side effects of
immunosuppression
Immunosuppression is a reduction of the activation or efficacy of the immune system. Some portions of the immune system itself have immunosuppressive effects on other parts of the immune system, and immunosuppression may occur as an adverse react ...
(metabolic disorders, malignancies, opportunistic infections) which is a predominant issue. The risk of transmitting infection is high.
Medical grafting
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 techniqu ...