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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