Transplantable organs and tissues
Encyclopedia
Transplantable organs and tissues may both refer to organs and tissues that are relatively often or routinely transplanted (here "main organs and tissues"), as well as relatively seldom transplanted organs and tissues and ones on the experimental stage.
Heart transplantation is performed on patients with end-stage heart failure or severe coronary artery disease. The most common procedure is to take a working heart
from a recently deceased organ donor (allograft) and implant it into the patient. The patient's own heart may either be removed (orthotopic procedure) or, less commonly, left in to support the donor heart (heterotopic procedure). It is also possible to take a heart from another species (xenograft), or implant a man-made artificial one
, although the outcome of these two procedures has been less successful in comparison to the far more commonly performed allografts.
patients.
While the precise details of surgery will depend on the exact type of transplant, there are many steps which are common to all of these procedures. Prior to operating on the recipient, the transplant surgeon inspects the donor lung(s) for signs of damage or disease. If the lung or lungs are approved, then the recipient is connected to an IV
line and various monitoring equipment, including pulse oximetry
. The patient will be given general anesthesia
, and a machine will breathe for him or her.
It takes about one hour for the pre-operative preparation of the patient. A single lung transplant takes about four to eight hours, while a double lung transplant takes about six to twelve hours to complete. A history of prior chest surgery may complicate the procedure and require additional time.
and lungs in a single operation. Due to a shortage of suitable donors, it is a rare procedure; only about a hundred such transplants are performed each year in the USA.
The patient is anesthetised
. When the donor organs arrive, they are checked for fitness; if any organs show signs of damage, they are discarded and the operation cancelled. Some patients are concerned that their organs will be removed and the donor organs won't be suitable. Since this is a possibility, it is standard procedure that the patient is not operated on until the donor organs arrive and are judged suitable, despite the time delay this involves.
Once suitable donor organs are present, the surgeon
makes an incision starting above and finishing below the sternum, cutting all the way to the bone. The skin edges are retracted to expose the sternum. Using a bone saw, the sternum is cut down the middle. Rib spreaders are inserted in the cut, and spread the ribs to give access to the heart and lungs of the patient.
The patient is connected to a heart-lung machine, which circulates and oxygenates blood. The surgeon removes the failing heart and lungs. Most surgeons endeavour to cut blood vessels as close as possible to the heart to leave room for trimming, especially if the donor heart is of a different size than the original organ.
The donor heart and lungs are positioned and sewn into place. As the donor organs warm up to body temperature, the lungs begin to inflate. The heart may fibrillate
at first - this occurs because the cardiac muscle
fibres are not contracting synchronously. Internal paddles can be used to apply a small electric shock to the heart to restore proper rhythm.
Once the donor organs are functioning normally, the heart-lung machine is withdrawn, and the chest is closed.
Kidney transplantation is the organ transplant of a kidney
in a patient with end-stage renal disease. Kidney transplantation is typically classified as deceased-donor (formerly known as cadaveric) or living-donor transplantation depending on the source of the recipient organ. Living-donor renal transplants are further characterized as genetically related (living-related) or non-related (living-unrelated) transplants, depending on whether a biological relationship exists between the donor and recipient.
with a healthy liver allograft. The most commonly used technique is orthotopic transplantation, in which the native liver is removed and the donor organ is placed in the same anatomic location as the original liver. Liver transplantation nowadays is a well accepted treatment option for end-stage liver disease and acute liver failure.
(one that can produce insulin) into a person who has diabetes. Because the pancreas performs functions necessary in the digestion process, the recipient's native pancreas is left in place, and the donated pancreas attached in a different location. In the event of rejection of the new pancreas, the recipient could not survive without the native pancreas still in place. The healthy pancreas comes from a donor who has just died or it may be a partial pancreas from a living donor. Whole pancreas transplants from living donors are not possible, again because the pancreas is a necessary organ for digestion. At present, pancreas transplants are usually performed in persons with insulin-dependent diabetes who have severe complications.
In addition to skin, the transplant optimally includes bones, along with muscle, skin, blood vessels and nerves.
Corneal transplantation is a surgical procedure where a damaged or diseased cornea
is replaced by donated corneal tissue which has been removed from a recently deceased individual having no known diseases which might affect the viability of the donated tissue. The cornea is the clear part of eye
in front of the iris
and pupil
. The surgical procedure is performed by ophthalmologists
, medical doctors who specialize in eyes, and are often done on an outpatient basis (the patient goes home following surgery).
Skin grafting is often used to treat:
Skin grafts are often employed after serious injuries when some of the body's skin is damaged. Surgical removal (excision or debridement) of the damaged skin is followed by skin grafting. The grafting serves two purposes: it can reduce the course of treatment needed (and time in the hospital), and it can improve the function and appearance of the area of the body which receives the skin graft.
derived from the bone marrow
(that is, bone marrow transplantation) or blood
. Stem cell transplantation is a medical procedure in the fields of hematology
and oncology
, most often performed for people with diseases of the blood
, bone marrow
, or certain types of cancer
.
Stem cell transplantation was pioneered using bone-marrow-derived stem cells by a team at the Fred Hutchinson Cancer Research Center
from the 1950s through the 1970s led by E. Donnall Thomas
, whose work was later recognized with a Nobel Prize
in Physiology and Medicine. Thomas' work showed that bone marrow cells infused intravenously could repopulate the bone marrow and produce new blood cell
s. His work also reduced the likelihood of developing a life-threatening complication called graft-versus-host disease
.
The first physician to perform a successful human bone marrow transplant was Robert A. Good
.
With the availability of the stem cell growth factors GM-CSF and G-CSF, most hematopoietic stem cell transplantation procedures are now performed using stem cells collected from the peripheral blood, rather than from the bone marrow. Collecting peripheral blood stem cells provides a bigger graft, does not require that the donor be subjected to general anesthesia to collect the graft, results in a shorter time to engraftment, and may provide for a lower long-term relapse rate.
Hematopoietic stem cell transplantation remains a risky procedure with many possible complications; it has traditionally been reserved for patients with life-threatening diseases. While occasionally used experimentally in nonmalignant and nonhematologic indications such as severe disabling auto-immune disease and cardiovascular disease
, the risk of fatal complications appears too high to gain wider acceptance.
or blood-based products from one person into the circulatory system
of another. Blood transfusions can be life-saving in some situations, such as massive blood loss due to trauma
, or can be used to replace blood lost during surgery
. Blood transfusions may also be used to treat a severe anaemia or thrombocytopenia
caused by a blood disease. People suffering from hemophilia or sickle-cell disease
may require frequent blood transfusions. Early transfusions used Whole Blood
, but modern medical practice is to use only components of the blood.
it is available in Kenya
repair, nerve
repair, then vein repair. The operation typically lasts 8 to 12 hours. By comparison, a typical heart transplant operation lasts 6 to 8 hours.
The recipient of a hand transplant needs to take immunosuppressive drug
s, as the body's natural immune system
will try to reject
, or destroy, the hand. These drugs cause the recipient to have a weak immune system and suffer severely even from minor infections.
In 2008, surgeons in Munich transplanted two whole arms. The long term results remain to be seen.
, a healthy leg was transplanted from a dying conjoined twin to her sister. There is no need for immunosuppresion because of the identical genetic make-up of the donor and recipient.
The first allograft of a leg is scheduled for Summer 2010.
, face
, or penis transplant surgery are controversial because they are not necessary to ensure the life of the patient.
which has undergone necrosis
. Though the procedure has significant potential, it has been performed only a few times.
, which results in an absent or hypoplastic thymus, in turn causing problems with the immune system
's T-cell mediated response. It is exclusively used in people with complete DiGeorge anomaly, which are entirely athymic. This subgroup represents less than 1% of DiGeorge syndrome patients.
The Chicago Project headed at University of Illinois at Chicago Medical Center is investigating ways to regenerate beta cells in vivo. With that being said, beta cells experience apoptosis
early and thus are destroyed within a normal-functioning pancreas. The source of this seems to come from the transfer of Pander
, a gene that works by attaching to RNA
. Pander, when active, causes the beta cells to be blocked at S phase
, which induces apoptosis. This loss of beta cell mass eventually leads to a loss of most of the transplanted beta cells.
, or Xenograft, which means a transplant from one species (in this case a pig) to another. There are some risks associated with a Xenograft such as the human body's tendency to reject foreign material. Medication can be used to retard this effect, but is not always successful.
Heart
Heart
The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...
from a recently deceased organ donor (allograft) and implant it into the patient. The patient's own heart may either be removed (orthotopic procedure) or, less commonly, left in to support the donor heart (heterotopic procedure). It is also possible to take a heart from another species (xenograft), or implant a man-made artificial one
Artificial heart
An artificial heart is a mechanical device that replaces the heart. Artificial hearts are typically used in order to bridge the time to heart transplantation, or to permanently replace the heart in case transplantation is impossible...
, although the outcome of these two procedures has been less successful in comparison to the far more commonly performed allografts.
Lung
While lung transplants carry certain associated risks, they can also extend life expectancy and enhance the quality of life for end-stage pulmonaryRespiratory failure
The term respiratory failure, in medicine, is used to describe inadequate gas exchange by the respiratory system, with the result that arterial oxygen and/or carbon dioxide levels cannot be maintained within their normal ranges. A drop in blood oxygenation is known as hypoxemia; a rise in arterial...
patients.
While the precise details of surgery will depend on the exact type of transplant, there are many steps which are common to all of these procedures. Prior to operating on the recipient, the transplant surgeon inspects the donor lung(s) for signs of damage or disease. If the lung or lungs are approved, then the recipient is connected to an IV
Intravenous therapy
Intravenous therapy or IV therapy is the infusion of liquid substances directly into a vein. The word intravenous simply means "within a vein". Therapies administered intravenously are often called specialty pharmaceuticals...
line and various monitoring equipment, including pulse oximetry
Pulse oximetry
Pulse oximetry is a non-invasive method allowing the monitoring of the oxygenation of a patient's hemoglobin.A sensor is placed on a thin part of the patient's body, usually a fingertip or earlobe, or in the case of an infant, across a foot....
. The patient will be given general anesthesia
Anesthesia
Anesthesia, or anaesthesia , traditionally meant the condition of having sensation blocked or temporarily taken away...
, and a machine will breathe for him or her.
It takes about one hour for the pre-operative preparation of the patient. A single lung transplant takes about four to eight hours, while a double lung transplant takes about six to twelve hours to complete. A history of prior chest surgery may complicate the procedure and require additional time.
Heart-lung
A heart-lung transplant is a procedure carried out to replace both heartHeart
The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...
and lungs in a single operation. Due to a shortage of suitable donors, it is a rare procedure; only about a hundred such transplants are performed each year in the USA.
The patient is anesthetised
Anesthesia
Anesthesia, or anaesthesia , traditionally meant the condition of having sensation blocked or temporarily taken away...
. When the donor organs arrive, they are checked for fitness; if any organs show signs of damage, they are discarded and the operation cancelled. Some patients are concerned that their organs will be removed and the donor organs won't be suitable. Since this is a possibility, it is standard procedure that the patient is not operated on until the donor organs arrive and are judged suitable, despite the time delay this involves.
Once suitable donor organs are present, the surgeon
Surgery
Surgery is an ancient medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, or to help improve bodily function or appearance.An act of performing surgery may be called a surgical...
makes an incision starting above and finishing below the sternum, cutting all the way to the bone. The skin edges are retracted to expose the sternum. Using a bone saw, the sternum is cut down the middle. Rib spreaders are inserted in the cut, and spread the ribs to give access to the heart and lungs of the patient.
The patient is connected to a heart-lung machine, which circulates and oxygenates blood. The surgeon removes the failing heart and lungs. Most surgeons endeavour to cut blood vessels as close as possible to the heart to leave room for trimming, especially if the donor heart is of a different size than the original organ.
The donor heart and lungs are positioned and sewn into place. As the donor organs warm up to body temperature, the lungs begin to inflate. The heart may fibrillate
Fibrillation
Fibrillation is the rapid, irregular, and unsynchronized contraction of muscle fibers. An important occurrence is with regards to the heart.-Cardiology:There are two major classes of cardiac fibrillation: atrial fibrillation and ventricular fibrillation....
at first - this occurs because the cardiac muscle
Cardiac muscle
Cardiac muscle is a type of involuntary striated muscle found in the walls and histologic foundation of the heart, specifically the myocardium. Cardiac muscle is one of three major types of muscle, the others being skeletal and smooth muscle...
fibres are not contracting synchronously. Internal paddles can be used to apply a small electric shock to the heart to restore proper rhythm.
Once the donor organs are functioning normally, the heart-lung machine is withdrawn, and the chest is closed.
Kidney
Kidney
The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...
in a patient with end-stage renal disease. Kidney transplantation is typically classified as deceased-donor (formerly known as cadaveric) or living-donor transplantation depending on the source of the recipient organ. Living-donor renal transplants are further characterized as genetically related (living-related) or non-related (living-unrelated) transplants, depending on whether a biological relationship exists between the donor and recipient.
Liver
Liver transplantation is the replacement of a diseased liverLiver
The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...
with a healthy liver allograft. The most commonly used technique is orthotopic transplantation, in which the native liver is removed and the donor organ is placed in the same anatomic location as the original liver. Liver transplantation nowadays is a well accepted treatment option for end-stage liver disease and acute liver failure.
Pancreas
A pancreas transplant involves implanting a healthy pancreasPancreas
The pancreas is a gland organ in the digestive and endocrine system of vertebrates. It is both an endocrine gland producing several important hormones, including insulin, glucagon, and somatostatin, as well as a digestive organ, secreting pancreatic juice containing digestive enzymes that assist...
(one that can produce insulin) into a person who has diabetes. Because the pancreas performs functions necessary in the digestion process, the recipient's native pancreas is left in place, and the donated pancreas attached in a different location. In the event of rejection of the new pancreas, the recipient could not survive without the native pancreas still in place. The healthy pancreas comes from a donor who has just died or it may be a partial pancreas from a living donor. Whole pancreas transplants from living donors are not possible, again because the pancreas is a necessary organ for digestion. At present, pancreas transplants are usually performed in persons with insulin-dependent diabetes who have severe complications.
Face
A face transplant is a still-experimental procedure.In addition to skin, the transplant optimally includes bones, along with muscle, skin, blood vessels and nerves.
Cornea
Cornea
The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber. Together with the lens, the cornea refracts light, with the cornea accounting for approximately two-thirds of the eye's total optical power. In humans, the refractive power of the cornea is...
is replaced by donated corneal tissue which has been removed from a recently deceased individual having no known diseases which might affect the viability of the donated tissue. The cornea is the clear part of eye
Human eye
The human eye is an organ which reacts to light for several purposes. As a conscious sense organ, the eye allows vision. Rod and cone cells in the retina allow conscious light perception and vision including color differentiation and the perception of depth...
in front of the iris
Iris (anatomy)
The iris is a thin, circular structure in the eye, responsible for controlling the diameter and size of the pupils and thus the amount of light reaching the retina. "Eye color" is the color of the iris, which can be green, blue, or brown. In some cases it can be hazel , grey, violet, or even pink...
and pupil
Pupil
The pupil is a hole located in the center of the iris of the eye that allows light to enter the retina. It appears black because most of the light entering the pupil is absorbed by the tissues inside the eye. In humans the pupil is round, but other species, such as some cats, have slit pupils. In...
. The surgical procedure is performed by ophthalmologists
Ophthalmology
Ophthalmology is the branch of medicine that deals with the anatomy, physiology and diseases of the eye. An ophthalmologist is a specialist in medical and surgical eye problems...
, medical doctors who specialize in eyes, and are often done on an outpatient basis (the patient goes home following surgery).
Skin
- Extensive woundWoundA wound is a type of injury in which skin is torn, cut or punctured , or where blunt force trauma causes a contusion . In pathology, it specifically refers to a sharp injury which damages the dermis of the skin.-Open:...
ing or traumaPhysical traumaTrauma refers to "a body wound or shock produced by sudden physical injury, as from violence or accident." It can also be described as "a physical wound or injury, such as a fracture or blow." Major trauma can result in secondary complications such as circulatory shock, respiratory failure and death... - BurnsBurn (injury)A burn is a type of injury to flesh caused by heat, electricity, chemicals, light, radiation or friction. Most burns affect only the skin . Rarely, deeper tissues, such as muscle, bone, and blood vessels can also be injured...
- Areas of prior infection with extensive skin loss
- Specific surgeries that may require skin grafts for healing to occur
Skin grafts are often employed after serious injuries when some of the body's skin is damaged. Surgical removal (excision or debridement) of the damaged skin is followed by skin grafting. The grafting serves two purposes: it can reduce the course of treatment needed (and time in the hospital), and it can improve the function and appearance of the area of the body which receives the skin graft.
Hematopoietic stem cells (bone marrow)
Hematopoietic stem cell transplantation (HSCT) is the transplantation of blood stem cellsPluripotential hemopoietic stem cell
Hematopoietic stem cells , also spelled Hæmatopoietic stem cells, are multipotent stem cells that give rise to all the blood cell types from the myeloid , and lymphoid lineages...
derived from the bone marrow
Bone marrow
Bone marrow is the flexible tissue found in the interior of bones. In humans, bone marrow in large bones produces new blood cells. On average, bone marrow constitutes 4% of the total body mass of humans; in adults weighing 65 kg , bone marrow accounts for approximately 2.6 kg...
(that is, bone marrow transplantation) or blood
Blood
Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....
. Stem cell transplantation is a medical procedure in the fields of hematology
Hematology
Hematology, also spelled haematology , is the branch of biology physiology, internal medicine, pathology, clinical laboratory work, and pediatrics that is concerned with the study of blood, the blood-forming organs, and blood diseases...
and oncology
Oncology
Oncology is a branch of medicine that deals with cancer...
, most often performed for people with diseases of the blood
Blood
Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....
, bone marrow
Bone marrow
Bone marrow is the flexible tissue found in the interior of bones. In humans, bone marrow in large bones produces new blood cells. On average, bone marrow constitutes 4% of the total body mass of humans; in adults weighing 65 kg , bone marrow accounts for approximately 2.6 kg...
, or certain types of cancer
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
.
Stem cell transplantation was pioneered using bone-marrow-derived stem cells by a team at the Fred Hutchinson Cancer Research Center
Fred Hutchinson Cancer Research Center
The Fred Hutchinson Cancer Research Center, is one of the world’s leading cancer research institutes...
from the 1950s through the 1970s led by E. Donnall Thomas
E. Donnall Thomas
Dr. Edward Donnall Thomas is an American physician, professor emeritus at the University of Washington, and director emeritus of the clinical research division at the Fred Hutchinson Cancer Research Center. In 1990 he shared the Nobel Prize in Physiology or Medicine with Joseph E. Murray for the...
, whose work was later recognized with a Nobel Prize
Nobel Prize
The Nobel Prizes are annual international awards bestowed by Scandinavian committees in recognition of cultural and scientific advances. The will of the Swedish chemist Alfred Nobel, the inventor of dynamite, established the prizes in 1895...
in Physiology and Medicine. Thomas' work showed that bone marrow cells infused intravenously could repopulate the bone marrow and produce new blood cell
Blood cell
A blood cell, also called a hematocyte, is a cell normally found in blood. In mammals, these fall into three general categories:* red blood cells — Erythrocytes* white blood cells — Leukocytes* platelets — Thrombocytes...
s. His work also reduced the likelihood of developing a life-threatening complication called graft-versus-host disease
Graft-versus-host disease
Graft-versus-host disease is a common complication after a stem cell transplant or bone marrow transplant from another person . Immune cells in the donated marrow or stem cells recognize the recipient as "foreign". The transplanted immune cells then attack the host's body cells...
.
The first physician to perform a successful human bone marrow transplant was Robert A. Good
Robert A. Good
-External links:** can be found at The Center for the History of Medicine at the Countway Library, Harvard Medical School....
.
With the availability of the stem cell growth factors GM-CSF and G-CSF, most hematopoietic stem cell transplantation procedures are now performed using stem cells collected from the peripheral blood, rather than from the bone marrow. Collecting peripheral blood stem cells provides a bigger graft, does not require that the donor be subjected to general anesthesia to collect the graft, results in a shorter time to engraftment, and may provide for a lower long-term relapse rate.
Hematopoietic stem cell transplantation remains a risky procedure with many possible complications; it has traditionally been reserved for patients with life-threatening diseases. While occasionally used experimentally in nonmalignant and nonhematologic indications such as severe disabling auto-immune disease and cardiovascular disease
Cardiovascular disease
Heart disease or cardiovascular disease are the class of diseases that involve the heart or blood vessels . While the term technically refers to any disease that affects the cardiovascular system , it is usually used to refer to those related to atherosclerosis...
, the risk of fatal complications appears too high to gain wider acceptance.
Blood
Blood transfusion is the process of transferring bloodBlood
Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....
or blood-based products from one person into the circulatory system
Circulatory system
The circulatory system is an organ system that passes nutrients , gases, hormones, blood cells, etc...
of another. Blood transfusions can be life-saving in some situations, such as massive blood loss due to trauma
Physical trauma
Trauma refers to "a body wound or shock produced by sudden physical injury, as from violence or accident." It can also be described as "a physical wound or injury, such as a fracture or blow." Major trauma can result in secondary complications such as circulatory shock, respiratory failure and death...
, or can be used to replace blood lost during surgery
Surgery
Surgery is an ancient medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, or to help improve bodily function or appearance.An act of performing surgery may be called a surgical...
. Blood transfusions may also be used to treat a severe anaemia or thrombocytopenia
Thrombocytopenia
Thrombocytopenia is a relative decrease of platelets in blood.A normal human platelet count ranges from 150,000 to 450,000 platelets per microliter of blood. These limits are determined by the 2.5th lower and upper percentile, so values outside this range do not necessarily indicate disease...
caused by a blood disease. People suffering from hemophilia or sickle-cell disease
Sickle-cell disease
Sickle-cell disease , or sickle-cell anaemia or drepanocytosis, is an autosomal recessive genetic blood disorder with overdominance, characterized by red blood cells that assume an abnormal, rigid, sickle shape. Sickling decreases the cells' flexibility and results in a risk of various...
may require frequent blood transfusions. Early transfusions used Whole Blood
Whole blood
Whole blood is a term used in transfusion medicine for human blood from a standard blood donation. The blood is typically combined with an anticoagulant during the collection process, but is generally otherwise unprocessed...
, but modern medical practice is to use only components of the blood.
it is available in Kenya
Hands
The operation is carried out in the following order: bone fixation, tendon repair, arteryArtery
Arteries are blood vessels that carry blood away from the heart. This blood is normally oxygenated, exceptions made for the pulmonary and umbilical arteries....
repair, nerve
Nerve
A peripheral nerve, or simply nerve, is an enclosed, cable-like bundle of peripheral axons . A nerve provides a common pathway for the electrochemical nerve impulses that are transmitted along each of the axons. Nerves are found only in the peripheral nervous system...
repair, then vein repair. The operation typically lasts 8 to 12 hours. By comparison, a typical heart transplant operation lasts 6 to 8 hours.
The recipient of a hand transplant needs to take immunosuppressive drug
Immunosuppressive drug
Immunosuppressive drugs or immunosuppressive agents are drugs that inhibit or prevent activity of the immune system. They are used in immunosuppressive therapy to:...
s, as the body's natural immune system
Immune system
An immune system is a system of biological structures and processes within an organism that protects against disease by identifying and killing pathogens and tumor cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own...
will try to reject
Transplant rejection
Transplant rejection occurs when transplanted tissue is rejected by the recipient's immune system, which destroys the transplanted tissue. Transplant rejection can be lessened by determining the molecular similitude between donor and recipient and by use of immunosuppressant drugs after...
, or destroy, the hand. These drugs cause the recipient to have a weak immune system and suffer severely even from minor infections.
In 2008, surgeons in Munich transplanted two whole arms. The long term results remain to be seen.
Leg
In ischiopagic conjoined twinsConjoined twins
Conjoined twins are identical twins whose bodies are joined in utero. A rare phenomenon, the occurrence is estimated to range from 1 in 50,000 births to 1 in 100,000 births, with a somewhat higher incidence in Southwest Asia and Africa. Approximately half are stillborn, and a smaller fraction of...
, a healthy leg was transplanted from a dying conjoined twin to her sister. There is no need for immunosuppresion because of the identical genetic make-up of the donor and recipient.
The first allograft of a leg is scheduled for Summer 2010.
Penis
The penis may be an allograft from a human donor, or it may be grown artificially, though the latter is untested in humans. Peripheral transplant procedures such as handHand transplant
Hand transplantation is a surgical procedure to transplant a hand from one human to another.The operation is carried out in the following order: bone fixation, tendon repair, artery repair, nerve repair, then vein repair. The operation typically lasts 8 to 12 hours...
, face
Face transplant
A face transplant is a still-experimental procedure to replace all or part of a person's face. The world's first full face transplant was completed in Spain in 2010.-Beneficiaries of face transplant:...
, or penis transplant surgery are controversial because they are not necessary to ensure the life of the patient.
Bone
Bone grafting is a surgical procedure that replaces missing bone with material from the patient's own body, an artificial, synthetic, or natural substitute. Bone grafting is used to repair bone fractures that are extremely complex, pose a significant health risk to the patient, or fail to heal properly.Uterus
A uterine transplant is the replace an uterusUterus
The uterus or womb is a major female hormone-responsive reproductive sex organ of most mammals including humans. One end, the cervix, opens into the vagina, while the other is connected to one or both fallopian tubes, depending on the species...
which has undergone necrosis
Necrosis
Necrosis is the premature death of cells in living tissue. Necrosis is caused by factors external to the cell or tissue, such as infection, toxins, or trauma. This is in contrast to apoptosis, which is a naturally occurring cause of cellular death...
. Though the procedure has significant potential, it has been performed only a few times.
Small bowel
Small bowel transplantation (SBT) was carried out 180 times in 2009 in the United States. Currently, approximately half are pediatric recipients. The most common indications in adults are ischemia (22%), Crohn's disease (13%), trauma (12%), and desmoid tumor (10%); and in pediatrics, gastroschisis (21%), volvulus (18%), and necrotizing enterocolitis (12%). Higher graft and patient survival rates are seen at the more experienced transplant programs. Within the last few years, 1-year graft and patient survival at more experienced centers have reached 60% to 70% and 65% to 80%, respectively.Thymus
Thymus transplantation can be used to treat infants with DiGeorge syndromeDiGeorge syndrome
22q11.2 deletion syndrome, which has several presentations including DiGeorge syndrome , DiGeorge anomaly, velo-cardio-facial syndrome, Shprintzen syndrome, conotruncal anomaly face syndrome, Strong syndrome, congenital thymic aplasia, and thymic hypoplasia is a syndrome caused by the deletion of a...
, which results in an absent or hypoplastic thymus, in turn causing problems with the immune system
Immune system
An immune system is a system of biological structures and processes within an organism that protects against disease by identifying and killing pathogens and tumor cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own...
's T-cell mediated response. It is exclusively used in people with complete DiGeorge anomaly, which are entirely athymic. This subgroup represents less than 1% of DiGeorge syndrome patients.
Islets of Langerhans
Islet cell transplantation has the possibility of restoring beta cells and curing diabetes.The Chicago Project headed at University of Illinois at Chicago Medical Center is investigating ways to regenerate beta cells in vivo. With that being said, beta cells experience apoptosis
Apoptosis
Apoptosis is the process of programmed cell death that may occur in multicellular organisms. Biochemical events lead to characteristic cell changes and death. These changes include blebbing, cell shrinkage, nuclear fragmentation, chromatin condensation, and chromosomal DNA fragmentation...
early and thus are destroyed within a normal-functioning pancreas. The source of this seems to come from the transfer of Pander
Pander
Pander may refer to:* Derek Pander, a fictional comedy character* Pander , the facilitation or provision of a prostitute in the arrangement of a sex act with a customer...
, a gene that works by attaching to RNA
RNA
Ribonucleic acid , or RNA, is one of the three major macromolecules that are essential for all known forms of life....
. Pander, when active, causes the beta cells to be blocked at S phase
S phase
S-phase is the part of the cell cycle in which DNA is replicated, occurring between G1 phase and G2 phase. Precise and accurate DNA replication is necessary to prevent genetic abnormalities which often lead to cell death or disease. Due to the importance, the regulatory pathways that govern this...
, which induces apoptosis. This loss of beta cell mass eventually leads to a loss of most of the transplanted beta cells.
Heart valve
Biological valves are valves of animals, like pigs, which undergo several chemical procedures in order to make them suitable for implantation in the human heart. The porcine (or pig) heart is most similar to the human heart, and therefore represents the best anatomical fit for replacement. Implantation of a porcine valve is a type of XenotransplantationXenotransplantation
Xenotransplantation , is the transplantation of living cells, tissues or organs from one species to another. Such cells, tissues or organs are called xenografts or xenotransplants...
, or Xenograft, which means a transplant from one species (in this case a pig) to another. There are some risks associated with a Xenograft such as the human body's tendency to reject foreign material. Medication can be used to retard this effect, but is not always successful.