Tuesday, 24 February 2015

On the Hunt for Organs

by Charlotte Randall


On the 1 December 2015, Wales will become the first country in the UK to start an opt-out organ system, meaning that every person, over the age of 18, who has lived in Wales for over 12 months will have to donate their organs, including the kidneys, heart, liver, lungs, pancreas and small bowel, for transplantation on the event of their death if they have not registered their decision not to. Why? Simply because there are not enough organs for those who need them.

Organ transplantation has become one of the most tremendous achievements in modern medicine and has dramatically improved life expectancy and quality of life after organ failure, especially with the kidneys. Due to its increasing success rate, organ transplantation has become a more popular and longer-lasting treatment for many patients suffering forms of organ failure and organ problems. However, there are a lack of donations. Indeed, there are increasingly high demands for organs, not only in Wales but also across the UK. Since April 2014, 2,901 people received organ transplantations; however, a further 6,842 people were still waiting for a donation. Moreover, the NHS website for organ donation claims that three people die daily in the UK in need of transplant. Due to this ever-growing problem, scientists are now beginning to look to combat this issue with alternatives to organic human organs by using the advances in scientific technology, especially in the form of genetic and organ engineering. 

An area, which has been widely researched, is Xenotransplantation, the process of transplanting organs or tissues between members of different species, in particular pigs and humans. Pigs have a compatible anatomy to human and for decades, humans have used tissues from pigs to construct replacement heart valves. Coupled with this, is the rapid breeding cycle of pigs meaning that could potentially be a large supply of organs. However, there is a problem. The human immune system tends not to like the presence of a pig organ, in particular the alpha-1,3-galactose enzyme (which is not present in humans) which coats the blood vessels, and sends white blood cells to attack and destroy it. However, Dr David Copper came up with a solution by genetically modifying the pigs to remove the gene that makes the enzyme, along with other genes that disturb the immune system, as well as adding several human genes to the pigs genome, making it less likely that the body will reject the organ. This also gives another advantage, as the patient may not have to use so many immunosuppressant drugs, which have disagreeable side effects such as nausea and vomiting. There have been positive results for transplanting genetically modified pig’s organs into other species, such as baboons. In August 2014, investigators from the National Heart, Lung, and Blood Institute (NHLMI), USA, transplanted a genetically modified piglet heart into a baboon, which was not rejected and has now lasted for over a year, making many scientists hopeful that this research will progress to humans. Indeed, there are high hopes for Xenotransplantation with predictions that some tissues could be used for corneal transplants or neuronal transplants for Parkinson’s disease. While we are a way off from total transplantation, as there are still fears that the pig organs could transmit disease to humans, it is being considered for short term transplantations, giving the patient more time to wait for a human donor.

A potential alternative to Xenotransplantation is Organ Decellularization, building up a new organ from the basic shape and frame structure of the old, essentially growing a organ from the patient’s own cells. There are immediate advantages with this as it avoids the issues with the body’s immune system rejecting the organ and there is no chance of Zoonosis, diseases that can cross the species barrier from animal to human. In 2008, Dr Ott and Dr Taylor created a beating rat heart from a framework of the old. They used detergents to strip the cells from the heart, leaving behind an extracellular framework of connective proteins such as collagen and laminin. They then inserted cells from new born rats and incubated it in a bioreactor-a vessel, which provides the cells with the correct conditions for chemical reactions to occur and thus stimulate blood flow. After four days muscle started to grow and contract and after eight the heart began to beat. This ground-breaking discovery has been used by Paolo Macchiarini from the Karolinska Institute, Sweden, to construct new tracheas for nine people by using their own cells, grown on their decellularized tracheas, showing the real potential for this mechanism. However, this system depends on an already existing organ and if the patient’s organ’s framework is too badly damaged or unusable, we are back to the problem of donation. This problem was solved by a different approach by Macchiarini, who built up a trachea on an artificial, synthetic polymer scaffold. This is most likely to be the future of organ engineering, as organs could be quickly mass-produced. This idea is also apt for the current height of technological advancement in the form of 3D printers, which have the capability to produce the complex architecture of organs. Due to the popular interest in this field of engineering, lots of attention is being paid towards it and the advances are coming thick and fast making the reality of organ printing a real possibility in the next few years.


It would not be a story about medical advancement without discussing stem cells. Stem cells are undifferentiated cells of a multicellular organism, which form any type of cell in that organism, which make them perfect for using and constructing new organs. In 2013, a group of scientists in Japan managed to create small, mouse livers solely from stem cells in petri dishes. Once transplanted into the body of a mouse, the livers began to perform the functions of a human liver such as metabolizing drugs and producing proteins. Despite the basicity of these organs, they don’t have all the features of a human organ; it is a huge advancement in progression of creating 3D organs by cells only. Production of other organs such as kidneys, intestines and tissues through the use of stem cells is also being researched. However, the advancement may be slow. A full understanding of stem cells is not yet reached. Coupled with this is the huge ethical issues which surround this area of research which cause controversy. This may result in problems with the future of stem cell research. 

While these medical scientific advancements have the potential to solve the organ problem, all solutions are a long way off. Up until that day, there will still be many who will suffer without the organ transplants that they need. This does thus bring up the question: should the rest of the UK bring in an opt-out organ donation system? While there are religious and social objections to such a proposition, it will be the most simplistic way to supply our national organ demand. It has been seven years since the UK government has reviewed this idea in England. I believe England should follow Wales’ example and open up the question again and invite public consultation and debate. While we worry about creating a democratic system where people have the choice whether to participate or not, we allow people to die. Even if it is for a short period, I believe that it is immensely important to introduce this scheme and quickly.

Bibliography:
http://www.webmd.com/news/20130703/first-organ-grown-from-stem-cells-alone-report



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