RESEARCH PAPER BASED ON PATHOLOGY LECTURES AT MEDLINK 2014

THE DEVELOPMENT OF STEM CELL RESEARCH AND TREATMENTS WITHIN MEDICINE BY JENNA BUXTON Grade awarded: Pass with Merit RESEARCH PAPER BASED ON PATHOLOGY LECTURES AT MEDLINK 2014

ABSTRACT This paper discusses the current research reviewing the use of stem cells in medicine. It explores the potential use of stem cells to offer a cure for many debilitating and often fatal diseases, in contrast to the current methods of managing and dealing with the symptoms. Examples include Parkinson's, Alzheimer's, Macular degeneration, cancer, heart disease, organ failure and spinal cord injury. Additionally, this paper will evaluate how stem cells are used in drug development and understanding disease, and consider the many ethical issues surrounding their use. Different types of stem cells are discussed, including the exciting developments with Induced Pluripotent stem cells (IPSCs), and their relevance to the treatment of disease. Stem cells are already being used in medical treatments and have great potential for further cures and therapies. INTRODUCTION A stem cell is an undifferentiated cell, with the capability to proliferate and renew itself even after long periods of inactivity, as well as to differentiate into any other type of specialised cell to create tissue and organs. The body uses them to regenerate and repair damaged tissue and therefore if we can find a way to isolate, collect and control the division of these stem cells, there is the possibility to cure a wide array of disease. Not only diseases, but under certain conditions, stem cells could be used to grow organs or limbs. These could be transplanted without the use of any immunosuppressive drugs, as the genetic information of the newly grown tissue would be an exact match to that of the patient. Until recently, there have been three main types of stem cells that are available for use in research and therapy: embryonic, cord blood and somatic stem cells. Embryonic stem cells Embryonic stem cells are derived from a blastocyst - the inner mass of an embryo which is created only a few days after fertilisation. The blastocyst has to be removed in order to obtain the stem cells, which are normally acquired from spare embryos from IVF treatment, consequently causing many ethical issues that will be discussed later. The most prominent property of embryonic stem cells is their potency. They are pluripotent, allowing them to maintain the ability to differentiate into any cell in the entire body, or replicate themselves indefinitely. (Murnaghan I. 2014) These properties make embryonic cells much easier to cultivate and have a lot more potential in medicine than any other type of cell, despite some remaining tissue rejection issues. Cord blood stem cells At birth the placenta is covered in cord blood which contains cord blood stem cells. This is relatively easy to collect and generates fewer ethical issues than the collection of embryonic stem cells. However, cells collected from the cord blood have less ability to differentiate than those from an embryo. They are multipotent and haematopoietic, meaning that they have the capability to produce only blood cells. There have been claims that cord blood may contain other types of stem cells, however theses claims are very controversial and many scientists do not believe them to be true. The main use of cord blood stem cells is the treatment of cancerous blood disorders such as leukaemia or Fanconi anaemia. The 2

stem cells are transplanted into the blood to produce healthy blood cells to replace those that are damaged. Somatic stem cells Somatic stem cells are undifferentiated cells found in the midst of differentiated cells in an adult or fully developed child. For example the most commonly known somatic stem cells are located in the bone marrow, and these too are hematopoietic, only producing other cells in the blood. Other types include glial stem cells and mesenchymal stem cells. Somatic stem cells are the easiest to harvest and do not provoke as much ethical debate. However, like the cord blood stem cells, the fact they are multipotent means they are much harder to cultivate and are less versatile for use in medicine. Induced Pluripotent stem cells (IPSCs) IPSCs are stem cells created from fully differentiated body cells. In 2006 Shinya Yamanaka published his discovery that body cells from an adult can be taken and genetically reprogrammed back to a pluripotent state. By forcing them to express certain genes they can maintain the essential properties of an embryonic stem cell - to be unspecialized, to be capable of renewing themselves and to be able to differentiate into any type of specialized cell. This groundbreaking discovery led him to be awarded a Noble prize and opened the doors to the future of stem cell research and regenerative medicine. IPSCs share many similarities with embryonic stem cells, for example both can be processed in a laboratory to derive any type of specialized cell. Both can also be used to demonstrate how pluripotent cells differentiate and can be used to grow tissue within a laboratory to model diseases and test new drugs. IPSCs allow us to learn much more about the complexities of a stem cell and, most importantly, avoid the ethical issues of removing pluripotent stem cells from an embryo. This is because IPSCs are obtained in an entirely different way. Yamanaka discovered that by introducing certain genes under specific conditions to skin cells from a mouse, the skin cells began to reprogram themselves and within 2-3 weeks they had transformed into induced pluripotent stem cells. This method was then applied to humans allowing scientists to take cells from a patient in need of regenerative treatment, and with these cells which contain perfectly matching genetic information, produce cells in a pluripotent state. These can then be used to grow an unlimited supply of replacement tissue in order to transplant it back into the patient, with the hope of curing currently untreatable diseases or to replace artificial limbs/organs. DISCUSSION Uses of stem cells: Treatments Stem cells are involved in the treatment of many diseases, ranging from chronic neurodegenerative diseases to organ failure. I will discuss some of the examples in this section. Parkinson's disease One person in every 500 suffers from Parkinson's disease. It is a progressive chronic neurodegenerative disease affecting the way the movements of the muscle are controlled by the brain. Neurotransmitter substances are chemicals that are transmitted between the synapses of the neuron cells within the body. They communicate messages between cells in a multi-cellular organism and in the case of controlling muscle movement, the neurotransmitter substance dopamine is used. Dopamine is made by the brain cells in the substantia nigra and the effect of Parkinson's disease causes this part of the brain to begin to degenerate, reducing the number of nerve cells; consequently less dopamine is produced. Over time more and more nerve cells in the substantia nigra become damaged and die, producing less dopamine to 3

transmit messages between the brain and the muscles. This causes the loss of response of the muscles and the main symptoms of Parkinson's: shaking, stiffness, muscle rigidity and slow movement. At present, although there are no cures for Parkinson's, there are many medicines that manage the symptoms. They make life easier for the person suffering by compensating for the depleted dopamineproducing nerve cells. However, they cannot replace them. A study was carried out by research scientists in Lund University in Sweden (2014), to attempt to transplant stem cells into the brains of rats which had previously been injected with a toxin to prevent the production of dopamine, modelling the effects of Parkinson's. The dopamine-producing nerve cells were created from embryonic stem cells in a laboratory and then grafted into the rat's brain. About 4 months later Magnetic Resonance Imaging (MRI) scans, Positron Emission Tomography (PET) scans and behavioural tests were used to test the rats movement function. These indicated that the transplanted cells had multiplied and matured and were actively generating the Dopamine hormone, resulting in improved motor recovery in the rats. (Grealish S. et al 2014) This study suggests that is possible to create Dopamine producing nerve cells in a laboratory that will adjust to their new surrounding and successfully carry out the function that should occur normally. Furthermore, by combining this method with the use of IPSCs, the resistance to foreign tissue would be less, and the possibility of success would again be improved. Diabetes Diabetes is another worldwide problem with the number of cases increasing. In England alone there are around 3.1 million people living with diabetes which is expected to rise to around 4.6 million in the next 15 years. Diabetes is a condition that prevents the body from regulating blood sugar levels and can occur for a variety of reasons. Blood sugar level is controlled by a hormone, insulin, which is produced in the pancreas. Insulin causes proteins in the plasma membrane to remove glucose from the blood following food consumption. Diabetes occurs when this insulin does not function properly or when not enough is produced. Type 1 diabetes results from the body's failure to produce enough insulin due to the loss of insulin-producing beta cells in islets of Langerhans in the pancreas. Type 2 diabetes results when either the body fails to respond to the insulin properly due to a resistance, or damage to the beta cells consequently produces less insulin. Stem cells have enormous potential to cure this disease, which in the case of type 1 diabetes is currently 'incurable'. Although it is possible to transplant the islet cells, is very difficult due to a great lack of donors and tissue rejection. IPSCs or embryonic stem cells could be used to grow the beta cells in a laboratory, and then transplant them into the pancreas. Hopefully they then respond to the glucose levels in the blood and secrete insulin like any other beta cell would. Presently, scientists have been successful at transplanting insulin-producing cells into diabetic mice and using them to control the blood sugar levels of these mice. Beta cells made of IPSCs have been slightly less successful than those created from embryonic stem cells, although IPSCs combat the issue of tissue rejection. More research is still needed to apply this method to humans and unlock the full potential of the IPSCs in curing diabetes. Age-related Macular Degeneration Age-related macular degeneration (ARMD) is the most frequent cause of vision loss and blindness worldwide in people over the age of 50. According to recent predictions from the United Nations, the number of people affected by macular degeneration, will triple from present numbers to be around 70 million in 2050. (Chopdar A. et al 2003) 4

It is a progressive condition, caused by the gradual loss of central vision due to the partial breakdown of the retinal pigment epithelium and degeneration of the macula, as shown in Figure 1. Figure 1 Dry ARMD is the most common form and occurs when the macula slowly thins and deteriorates. Over time the number of cells affected increases, although generally it takes many years until sight is seriously affected. Wet ARMD occurs much more rapidly and causes more serious vision loss. This is because in addition to retinal pigment cells degenerating, tiny blood vessels grow and can leak blood and fluid, initiating scarring to the macula. Stem cells can be used in a similar way to treating Parkinson's, which shows the versatility of this treatment in the way that similar methods can be used to treat two entirely different conditions. Embryonic stem cells or IPSCs could be used to create a section of retinal tissue that could then be grafted into the retinal pigment epithelium. This replaces the damaged tissue to carry out the function of nourishing the rods and cones that make up the retina, potentially curing vision loss entirely. Uses of stem cells: Drug development and disease models Not only can stem cells be used extensively in therapy and treatment, but they can also be used in an entirely different area of medicine: drug development and understanding of disease. One of the most important steps in treating a disease is understanding the way it works, and pinpointing exactly what is going wrong in the body. With this knowledge it is easier to overcome and resolve the disease, whether that is by tissue regeneration, transplantation or the use of a certain drug. However, without the use of stem cells, it is very challenging to study the development of a disease among humans. Firstly, it is very difficult to observe the very first stages of the disease, when symptoms are not visible, as it is not possible to know exactly when it might occur and to whom. Secondly, it is difficult to isolate and study the individual cells that are responsible or affected by the disease within a living human body. With the use of IPSCs, scientists can access large numbers of a particular type of cell, for example the neurones that are affected by Parkinson's or Alzheimer's disease. First they must create IPSCs from body cells, from a patient suffering with Alzheimer's for example, and then use these to produce neurons. These will have exactly the same genetic background as the patient's own neurons, meaning it is possible to create a model of the disease that scientists can examine and study in detail. It would then be possible to test potential treatments without worrying about causing harm to the patient. Additionally, the ethical issues related to embryonic stem cells are not involved. These 'disease models' can be used to generate many genetically complicated disorders and even more importantly, create the large quantities of cells that are needed to test and develop new drugs. Potentially this could make human trials of new drugs much safer and avoid some side effects that might not necessarily show on animal and cultured tissue tests. Furthermore, it could solve a variety of ethical issues by decreasing the number of animals involved in testing by providing alternative forms of test tissue. (Hadenfeld M. 2012) One example of identifying underlying disease mechanisms is with Ciliopathies. This is a group of disorders related to genetic mutation in DNA that code for proteins and specifically the development 5

and function of cilia. The gene responsible for these abnormalities in the cilia has in fact already been identified. However, each individual person reacts very differently to the gene and it is hard to understand how one gene can have so many different effects and why particular mutations of that gene result in these particular effects. Here, IPSCs can be used to create several models of these Ciliopathy disorders and closely study the different mutations, effects that they cause, and possible treatments. (Watt F. 2014) Ethical issues In spite of the many revolutionary advances and possibilities that the use of stem cells could generate, there are significant issues, both ethical and scientific that surround stem cell research. Some of these restrict the rate at which research can take place, and include moral objections to stem cell therapies and treatments. One of the biggest issues with stem cell research is the method of obtaining pluripotent stem cells from the embryo. This is a much preferred source of stem cells, rather than somatic cells from an adult, as they have a much higher potency, potential, and are easier to cultivate. By taking the stem cells from the inner mass of a blastocyst in an embryo, the potential life of the embryo is destroyed, which many religious or pro-life supporters disagree with. From this arises the debate of when life actually begins. Some people, such as those from the Catholic Church, believe that life begins at conception and therefore to destroy an embryo is to destroy a life. However, on the other hand, an embryo does not have any thoughts or feelings, nor a heartbeat, or even tissue, and therefore is it classed as a life? Other religions such as Judaism suggest that life begins when a baby takes its first breath and so this may mean it is acceptable to use an embryo that is not actually alive? No matter what rules or regulations are developed to try to decipher exactly which moment it is that we start living, they will always produce contradictory views. Therefore the opinion that an embryo can be destroyed as it is not yet living, preventing it from developing into the individual it has potential to become, remains controversial. The answer to this problem could be using ISPCs in place of embryonic cells. Without involving an embryo and essentially another life, research suggests that IPSCs offer the same number of possibilities as embryonic stem cells, due to their pluripotency and embryonic-like traits. Other ethical issues include possible side effects related to stem cell therapy. For example, stem cells and cancerous tumour cells share very similar properties, in the way they both renew and regenerate themselves. For this reason transplanting or injecting stem cells into a patient as a treatment could potentially lead to the growth of a malignant tumour. Undoubtedly, this side effect could be fatal, raising the question, Is it worth putting the lives of patients at such a great risk? Whilst stem cells are at such an early stage of development, it is important to find the correct balance of potential benefit against risk. For example, it would be necessary assess the quality of the patient's life before treatment, and the expected change after treatment, as well as gaining informed consent from the patient before commencing stem cell therapy. In contrast, there have been over 8,000 cases where diseases have been successfully treated by the use of hematopoietic stem cells alone. A patient (on the National Cord Blood Programme website) described her experience as a fifteen year old. She was diagnosed with Acute Myeloid Leukaemia and after months of unsuccessful chemotherapy and radiation treatment, she received cord blood stem cell therapy which dramatically improved her quality of life. This is just one of the many examples that prove the years of research into stem cell therapy are worthwhile. However, where embryonic stem cells are involved, the ethical question remains, 'Is the benefit worth sacrificing the potential life of an embryo?' In order for many stem cell transplants to take place, stem cells from a donor are required, preferably matching the patient s own genetic makeup. Cord blood banks, such as Virgin Health Bank, store the cord blood taken from the placenta at birth in case it is needed for treatment later on in life, 6

overcoming this issue. However, this method could seem controversial for some. Despite the unequivocal benefits of cord blood stem cell therapies, this could be seen as unacceptably interfering with the course of nature. Some might think we should just accept death and illness as part of life. Moreover, where does the use of these stem cells stop? Stem cells stored in blood banks could be misused, inappropriately developed, or the data obtained from them unintentionally leaked by people who have access to them. Furthermore, when does an illness become bad enough to require regenerative tissue or stem cell therapy? What are the boundaries? For example, people may begin to alter the genes of stem cells, specifically programming them to achieve specific characteristics in babies, leading to the creation of designer babies. Although there are a lot of controversies related to genomics, on the other hand the benefits, such as cure of genetic disorders, could be incredible. CONCLUSION In conclusion, it is clear there are many advantages and disadvantages with the use of stem cells for treatment although it can be difficult to obtain the right balance, order to advance stem cell research in a way that is safe, and ethical. Despite the remarkable discoveries and opportunities that stem cell research has created, it is clear more research and development is needed before stem cells can be completely integrated within treatments, diagnosis and advances in medicine. I feel that time and resources should be focused on research of IPSCs specifically, which, in my opinion have the most potential in medical treatment. One example is the treatment of Parkinson s disease. Although tests have been carried out on mice, and have achieved successful results on transplanting functioning Dopamine-producing cells, tests have not yet been effectively carried out on humans. This applies with many potential treatments, proving more research is required. The next leap forward will be in the first human trials on actual patients, integrating the use of IPSCs, to help to provide evidence to find consistent and trustworthy treatments and cures. I also feel that within the excitement of stem cell research, it would be easy to be swept up in the potential advantages they might offer and in the future, it would be very important to maintain the correct goals. Tight ethical boundaries will be necessary to ensure progress continues in the right direction. Focus must remain on the well-being of, and benefits to the patient. This is especially important considering stem cell research is funded privately, and not by the NHS or government. Private investors may be funding the research only with the aim to make money, and this could detract away from the original purpose of stem cell therapy. Furthermore, the developments of such treatments and cures offer the possibility to continually extend life expectancy. However, a longer life expectancy may not in itself be beneficial and it is important to consider the quality of life, not just the quantity of life gained, again finding a balance between the two. As stem cell therapy is constantly evolving, with enormous potential to change thousands of lives across the globe, science has the responsibility to ensure this revolutionary process is developed with sufficient consideration of the moral and ethical issues surrounding treatment. With such potential, who knows what the future will bring. Although I expect the outcomes of stem cell research will be both positive and negative, I am certain that in years to come people will look back at these discoveries as one of the most significant of all time. REFERENCES Information on embryonic stem cells 7

National Institutes of Health (NIH) - modified March 2015 http://stemcells.nih.gov/info/basics/pages/basics3.aspx Report by Murnaghan I. (2014) http://www.explorestemcells.co.uk/embryonicstemcells.html Information on cord blood stem cells EuroStemCell and contributing authors (2008-2015) http://www.eurostemcell.org/factsheet/cord- blood- stem- cells- current- uses- and- future- challenges Advantages for preserving cord blood cells, Cryo cell international (2015) www.cryo- cell.com/healthcare- providers/therapeutic- advantages Information on adult stem cells Bedford Stem Cell Research Foundation http://www.bedfordresearch.org/stemcell/stemcell.php?item=what- is- a- stem- cell Noble prizes and laureates data The Nobel Prize in Physiology or Medicine 2012 Sir John B. Gurdon, Shinya Yamanaka, Nobel prize.org http://www.nobelprize.org/nobel_prizes/medicine/laureates/2012/press.html Information on Induced Pluripotent stem cells Deriving and using IPSCs, report by Takahashi K. et al (2007) http://www.bedfordresearch.org/articles/takahishihuipscell07.pdf report by UCLA, Eli and Edythe broad centre of regenerative medicine and stem cell research https://www.stemcell.ucla.edu/induced- pluripotent- stem- cells Using IPSC as disease models, information by Hadenfeld M. (2012) Euro Stem Cell http://www.eurostemcell.org/factsheet/ips- cells- and- reprogramming- turn- any- cell- body- stem- cell 8

Information on Parkinson's disease Patient UK http://www.patient.co.uk/doctor/parkinsonism- and- parkinsons- disease Statistics on Parkinson's disease, Parkinson's UK http://www.parkinsons.org.uk/content/what- parkinsons Study carried out by Lund University for the transplantation of stem cell to treat Parkinson's http://www.nhs.uk/news/2014/11november/pages?stemm- cells- could- repair- Parkinsons- damage.aspx http://www.lunduniversity.lu.se/article/stem- cell- transplants- for- parkinsons- disease- edging- closer Information on Ciliopathy disorders Ciliopathy disorders and using IPSCs to create disease model, public lecture by Professor Watt F. FRS (2014) The Royal Society https://royalsociety.org/events/2014/stem- cells/ Information on Diabetes Using stem cells to cure diabetes, Diabetes Institute Research Foundation (2014) http://www.diabetesresearch.org/stem- cells Information on Macular Degeneration Figure 1 http://www.crowsnesteye.com/patient- information/macular/ Statistics on Age related Macular degeneration, National Centre for Biotechnology Information, information by Chopdar A. et al (2003) BMJ Publishing Group Ltd http://www.ncbi.nlm.nih.gov/pmc/articles/pmc1125371/ 9

Information on the uses of stem cells within treatment Case of treating Myeloid Leukaemia with stem cells, National cord blood program Jaclyn Albanese www.nationalcordbloodprogram.com/patients/patient_albanese.html Stem cell research news http://www.stemcellresearchnews.net/real_life_examples.aspx Virgin Health Bank https://www.virgin.com/company/virgin- health- bank Successful transplant of dopamine producing neurones report by Grealish S. et al (2014), Cell Press www.cell.com/cell- stem- cell/abstract/s1934-5909(14)00408-1 Similarities between stem cells and cancer cells Nature www.nature.com/nature/journal/v414/n6859/abs/414105x0.html Cancer stem cells, Oxford stem cell institute report by O'Neil E. et al (2008) www.stemcells.ox.ac.uk/cancer- stem- cells 10