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Last month marked one of the most important Nobel Prizes awarded in the field of medicine and physiology. Sir John B. Gurdon and Shinya Yamanaka were awarded the prize for “….the discovery that mature cells can be reprogrammed to become pluripotent". The importance of this work cannot be understated. This discovery has implications which go beyond any experimental work in the lab. Instead it lays the groundwork for treating patients on a personal level.
As we age the cells that make up our body divide at a slower pace. In addition to slower proliferation, aged stem cells have a more difficult time maturing. To further complicate matters individuals in need of organ transplantation and therapies are more than likely adults or elderly. The discovery made by Dr. Gurdon and Yamanaka demonstrates that adult cells can undergo back differentiation and become more stem cell like. In other words, they behave more like cells in embryonic development. As a result a mature cell such as a muscle cell or an adipocyte can undergo transformation. Proliferation and cell viability increases as a result. At this point the cells can be differentiated into another cell type such as cardiac cells, hepatocytes, or neural cells.
This has enormous implications for medicine and future doctors will be faced with challenges and procedures that pertain to (directly or indirectly) this discovery. For example in the field of tissue engineering researchers are slaving away at developing artificial organs. This would eliminate the need for rejection medications and the need for an organ donor. Published very recently (June 14th 2012) in The Lancet there was a bioengineered vein which was implanted into a 10 year old girl. This was another major breakthrough paving the way for off the shelf vascular grafts. The construct was made using the patient’s own stem cells eliminating the need for high dosages of rejection medications. However, if this same surgery were to be done on a 70 year old individual; cell isolation and expansion can become problematic. This is why understanding how to make aged cells behave more plastic is vital to future research and medical practice because these procedures will no longer be limited to young children and infants; they will become the gold standard for coronary artery transplantation and reconstruction surgery for adults as well.
Another case in point is complete organ transplantation. Take for example the work done by Dr. Doris A Taylor. In Feb 2008 Dr. Taylor published an article in Nature Medicine demonstrating that a rat heart can be completely decellularized, and then recellularized with cardiac or endothelial cells. After conditioning in a bioreactor the constructs were able to generate pump function (approx. 2%). While this is admittedly small, this is proof of concept that entire organs do not have to be from an organ donor. Instead the patient’s own cells can be used to repopulate and grow within a tissue engineered scaffold and function. These breakthroughs coupled with Dr. Sir John B. Gurdon and Shinya Yamanaka’s work mean that medical doctors will face a completely new way of how they treat patients. Instead, their patients will be treated independently and the development of future artificial organs may begin with the patients themselves.