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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.
Main organs
Heart
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.
Lung
While lung transplants carry certain associated risks, they can also extend life expectancy and enhance the quality of life for end-stage pulmonary 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.[1]
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.[1]
Heart-lung
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
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.
Liver
Pancreas
Face
In addition to skin, the transplant optimally includes bones, along with muscle, skin, blood vessels and nerves.
Main tissues and cells
Cornea
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
Skin grafting is often used to treat:
- Extensive wounding or trauma
- Burns
- 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)
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 cells. His work also reduced the likelihood of developing a life-threatening complication called graft-versus-host disease.[3]
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[4] 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.[5][6]
Blood
Other organs
Hands
The recipient of a hand transplant needs to take immunosuppressive drugs, 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.[7] The long term results remain to be seen.
Leg
In ischiopagic conjoined twins, a healthy leg was transplanted from a dying conjoined twin to her sister.[8] There is no need for immunosuppresion because of the identical genetic make-up of the donor and recipient.
Penis
Bone
Uterus
Small bowel
Small bowel transplantation (SBT) is carried out 100 times per year in the US.[9] Between 60 and 70 of the recipients are age 18 and under. Main underlying cause is intestinal failure by disease or by trauma, affecting nutrient absorption, movement of food through the intestinal tract or blood supply. [9]
It has a three-year survival rate of 70 percent and greater. [9]
Other cells and tissues
Islets of Langerhans
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[10]. 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.
Heart valve
Ovary
Ovary transplantation, giving rise to successful pregnancies, has so far only been carried out on identical twins, and will result in children who will have the genetic inheritance of the organ donor and the recipient. More importantly, use of an ovarian transplant from a genetically identical donor prevents rejection of the donated organ. This bypasses the need for immune suppressants to maintain the function of the donated ovary, which is not vital for survival.
