Organ donation is the process of surgically removing an organ or tissue from one person (the organ donor) and placing it into another person (the recipient). Transplantation is necessary because the recipient’s organ has failed or has been damaged by disease or injury. Organ transplantation is one of the great advances in modern medicine. Unfortunately, the need for organ donors is much greater than the number of people who actually donate.
Progress in solid organ transplantation began in the 1950s. Dr. Joseph E. Murray (who received the Nobel Prize for Medicine in 1990) achieved the first successful kidney transplant between identical twins in Boston in 1954. In 1967, a young South African heart surgeon named Christian Bernard became an international hero when he performed the first human heart transplant at Groote Schur Hospital in Cape Town.
Organs and tissues that can be transplanted include Liver, Kidney, Pancreas, Heart, Lung, Intestine, Cornea, Middle ear, Skin, Bone, Bone marrow, Heart valves, Connective tissue and Vascularized composite allografts (transplant of several structures that may include skin, bone, muscles, blood vessels, nerves, and connective tissue)
Here are some recent developments that could completely change the organ donation and transplantation system as we know it.
CREATING ORGANS FROM STEM CELLS
In April 2016, a 2-year-old girl became the sixth patient in the world to receive a windpipe transplant made from her own stem cells. The surgery was pioneered by Dr. Paolo Macchiarini, the director of the Advanced Center for Translational Regenerative Medicine. His procedure was approved by the FDA as an experimental operation for patients with very little hope of surviving. Stem cells are capable of becoming all different types of body cells, it’s believed they react to the environment in which they are transplanted and start reproducing the appropriate tissue.
A MACHINE THAT KEEP ORGANS ALIVE OUTSIDE THE BODY
Transplant teams have less than eight hours to transport the organ to the operating room, prepare it for surgery and implant it into the recipient’s body. “Beyond that time, there is a significant injury to the (organ), which makes it unusable,” said Dr. Abbas Ardehali, director of UCLA’s heart and lung transplant program. TransMedics developed a device called the Organ Care System (OCS). The machine is designed to replicate our human functions as closely as possible, by keeping the organs alive outside the body. These relatively new machines allow organs to remain outside the human body for extended periods without causing damage that the usual cold storage method often does. While these new technologies are not yet general practice and most are still in the developmental phase, the research and results show a promising future for creating and sustaining organs. Ultimately technology could eliminate the shortage of organs and even possibly the need for organ donors.
PRINTING 3D ORGANS
Scientists have developed a way to 3D print models of various anatomical structures, including hearts, brains, arteries, and bones. In the future, this process could be used to create 3D-printed soft implants in which living tissue can grow to form organs. Although the concept is still experimental, researchers have shown that it may one day be possible to use 3D printing to create replacement tissues and organs. We’re still many years away from doing this on a routine basis, but there’s hope that printing organs could one day supplement the shortage of live organs. – says Dr. Anthony Atala, a practicing surgeon and director of the Wake Forest Institute for Regenerative Medicine Printing more structural outer-tissue body parts may happen sooner. In 2013, researchers at Cornell University showed they were able to print a 3D replacement ear.
For instance, if surgeons could implant material into the heart, it could form a temporary scaffold to support cells and boost cellular reorganization. This so-called cardiac tissue engineering has a number of problems; primarily, scientists need to find a type of material that the body would not reject. Researchers have already tried a range of materials and methods, but the perfect candidates are cells from the body of the patient.
During recent years, researchers have made some progress toward artificially replicating human tissue. A group of scientists from Tel Aviv University in Israel has taken this work one step further and moved cardiac tissue engineering to the next stage. “This is the first time anyone anywhere has successfully engineered and printed an entire heart replete with cells, blood vessels, ventricles, and chambers.” Lead researcher Prof. Tal Dvir. The scientists have designed a groundbreaking approach that allows them to create the closest thing to an artificial heart to date. Their first step was to take a biopsy of fatty tissue from the patient; then, they separated cellular material from noncellular material.
The researchers reprogrammed the cells of the fatty tissue to become pluripotent stem cells, which can develop into the range of cell types necessary to grow a heart. The noncellular material consists of structural components, such as glycoproteins and collagen; the scientists modified these to turn them into a “Bio-Ink.” Then, they mixed this bio-ink with the stem cells. The cells differentiated into cardiac or endothelial cells (which line blood vessels), which the scientists could use to create cardiac patches, including blood vessels. They describe their methods in detail in a recent paper published in the journal Advanced Science.
‘THE SIZE OF RABBIT’S HEART’
“This heart is made from human cells and patient-specific biological materials. In our process these materials serve as the bio-inks, substances made of sugars and proteins that can be used for 3D printing of complex tissue models,” says Prof. Dvir. He goes on to say: “People have managed to 3D-print the structure of a heart in the past, but not with cells or with blood vessels. Our results demonstrate the potential of our approach for engineering personalized tissue and organ replacement in the future.”
To demonstrate the potential of their technique, the scientists created a small but anatomically precise heart, complete with blood vessels and cells. “At this stage, our 3D heart is small, the size of a rabbit’s heart,” says Prof. Dvir. “But larger human hearts require the same technology.” It is worth noting that this technology is still very far from being able to replace heart transplants. This is just another step along the path — albeit a rather large step. The crucial next task, as Prof. Dvir says, is to teach them to behave like hearts; he explains that they “need to develop the printed heart further. The cells need to form a pumping ability; they can currently contract, but we need them to work together.”
“Our hope,” he goes on, “is that we will succeed and prove our method’s efficacy and usefulness.”There is still a long road ahead, but the researchers are excited about how far they have come.