Stem Cells In The Treatment Of Cardiovascular Disease Biology Essay

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Stem Cell Research is believed by many to be the future of medical treatments, as stem cells have the unique ability to regenerate and differentiate into a variety of different cell types. Bone marrow and umbilical cord blood stem cells are already being used to treat leukaemia and cardiovascular disease. This is just the start of the potential benefits that could arise from stem cell research. In the future the use of embryonic stem cells, induced pluripotent stem cells (iPSCs), and genetically modified adult stem cells could offer a range of different treatments; including treatments for brain disease, spinal cord injury, heart disease and diabetes.

Background information on stem cells, and the ethical issues involved

2.1 Embryonic and adult stem cells

Embryonic stem cells come from the inner cell mass of a blastocyst - resulting in its destruction. Embryonic Stem Cells differ from adult Stem Cells in that they are pluripotent, meaning that they have the ability to differentiate into almost all cell types; essentially they can become any tissue in the body, excluding the placenta. Adult Stem Cells, on the other hand, are generally classified as multipotent, meaning that they are only able to become the cell types of their original tissue e.g. hematopoietic stem cells, or blood-forming stem cells, found in the bone-marrow can become all the types of blood cells in the body, but cannot form cells such as nerve cells. There are also usually only a small number of stem cells in any given tissue, with a limited ability to divide once taken out of the body. Given this, the use of embryonic stem cells, as opposed to adult stem cells, offers a far greater number of potential treatments.

2.2 Ethical Debate

Even though Stem Cell Research offers much potential, it does raise certain moral and ethical questions. The main ethical debate, in terms of the use of embryonic stem cells, is one of where life begins. Some would argue that life begins from the moment of conception, thereby rendering the destruction of a human blastocyst murder. Others would argue that life begins after a certain time period. It should also be noted that the embryos used in stem cell research/ treatments are usually the 'extras' from in vitro fertilisation (IVF), and are not derived from eggs fertilised inside a woman's body. As such, one can question the argument that the procurement of stem cells results in the destruction of a potential life, as the 'potential life' in question would be destroyed whether or not it was used in stem cell research.

Another ethical issue, which many individuals and religious bodies object to, is the creation of an organism with both human and animal tissue (called a chimera) in stem cell research. During the experimental stage of stem cell research, human stem cells are often inserted into the tissue of animals such as mice or rats. The 'part human' organism that is resultantly created is viewed by many as being an offense to the natural order of life and creation.

2.3 Possible solutions for ethical issues

In 2006, researchers discovered a way to stimulate some adult stem cells, through the production of embryonic genes to become like embryonic stem cells. These stem cells are called induced pluripotent stem cells (iPSCs). The methods by which iPSCs are created are still in the investigative stage. The creation of iPSCs can potentially eliminate ethical issues associated with embryonic stem cells, as well as some practical issues associated with the limited nature of adult stem cells. iPSCs could also create a greater possibility of autologous donations (where the donor and recipient are the same person), thereby creating stem cells lines that are completely specific to an individual person (this would obviously not be possible with embryonic stem cell lines) and also eliminating potential rejection/ compatibility issues associated with both embryonic and adult stem cells.

Stem Cells in the treatment of leukemia

Hematopoietic stem cells have been used in the treatment of conditions such as leukemia for some time. Leukemia is a cancer of the white blood cells, also known as leukocytes, responsible for fighting off infections in the body. Treating leukemia most commonly involves destroying all cancerous leukocytes through chemotherapy. The problem with this is that the drugs used destroy both cancerous cells and the hematopoietic stem cells within the bone marrow. Stem Cell transplantation (SCT) can be used to counter-act this effect. In SCT healthy stem cells are introduced into the patient's body to manufacture new blood cells in the bone marrow. These stem cells are most commonly gathered from bone marrow, but can also be gathered from umbilical cord blood.

Even though leukemia would be an ideal situation for autologous stem cells to be used, this would only be possible if the patients stem cells where harvested from bone marrow before the onset of leukemia, or alternatively from reserves of the patients umbilical cord blood. If the patient's stem cells are removed from bone marrow after the spread of leukemia has begun, it is difficult to separate healthy stem cells from leukemic stem cells. As such many leukemia patients who could benefit from stem cell treatment never find a compatible bone marrow donor. Even if they do, there is still the possibility of rejection or other complications such as chronic graft - versus - host disease where donor stem cells attack the patient's organs. The other option for leukemia sufferers is stem cells derived from umbilical cord blood. As umbilical cord blood contains a fraction of the stem cells found in bone marrow, leukemia patients who receive these transplants are left vulnerable to life-threatening diseases for a longer period of time. This year (2010) promising discoveries where made by the 'Fred Hutchinson Cancer Center' in Seattle, in terms of manipulating umbilical cord blood to expand the number of stem cells in a single unit of blood. In a human study researchers found the time it took for transplanted cells to start making white blood cells on their own was halved when manipulated blood cells, as opposed to conventional blood cells, where used. These advancements could possibly eliminate recipient-donor compatibility issues in the future, as umbilical cord stem cells do not need to be as perfectly matched to the recipient (umbilical cord stem cells, being less developed, do not have the same antigenic potential as bone marrow stem cells)

Stem cells in the treatment of cardiovascular disease

Stem Cell Treatments can also be used to treat cardiovascular disease, which is one of the leading natural causes of deaths in the world (particularly in America). In the case of a mycordial infarction (heart attack), a coronary artery becomes blocked, depriving the muscle tissue which it feeds of oxygen, and consequently that tissue dies, rendering the heart damaged and incapable of optimal performance. If stem cells are introduced into the blood stream, or directly into the heart tissue, after a heart attack, new blood vessels can be built and damaged heart tissue can be regenerated. Even though the ideal stem cell population to completely repair a damaged heart has not been discovered, preliminary experiments are underway to discover this ideal. In the future stem cell research could also be used to generate entirely new heart tissue, and other such vital tissues. Currently both embryonic stem cells and a variety of different adult stem cell types are being used to treat cardiovascular disease. The development of cardiac cells from stem cells also allows researchers to test drugs on actual human tissue.

Diagram to show potential stem cell treatment areas (taken from:

Risks of Stem Cell treatment

Even though Stem Cell Research offers the potential to combat a wide range of diseases, there are risks involved. Stem cell treatments that are not autologous can lead to cancer, particularly in the case of embryonic stem cells which rapidly differentiate. There is also the risk of immune rejection, particularly with adult stem cells, like bone marrow stem cells. Possible side effects from stem cell treatment in leukemia patients (apart from graft-versus-host disease) include: sterility, clot formation in the small blood vessels and endocrine system malfunction. Stem cell treatments in general can lead to tumour formation and inappropriate stem cell migration. There are also potential health risks to women who undergo hormonal treatments to stimulate the ovaries to produce multiple eggs (usually associated with in vitro fertilisation).

Stem Cell Research in South Africa

South Africa has fairly recently become involved in stem cell research, and the country has much potential in this field. Mark Shuttelworth has conducted various experiments with stem cells under zero gravity conditions. This unprecedented research is being used to discover the optimal conditions for stem cell development. The University of Stellenbosch is actively involved in this research, and has been involved in the establishment of South Africa's first stem cell bank, which is now operational. The collection, transportation and storage cost of stem cells collected from umbilical cord blood is R12 000 for the first 20 years. Thereafter storage will become an annual cost, which is unlikely to be very significant.

Legislation in S.A. governing stem cell research

7.1 Current Legislation

Currently the only laws in South Africa concerning stem cell research and stem cell treatments are found in the National Health Act No 61 of 2003. Chapter 8 deals with the control of the use of blood, blood products, tissue and gametes in humans. Section 55, prohibits the removal of tissue, blood, blood products or gametes from the body of a living person without their consent and if consent is given it must be for a prescribed medical purpose. The collection of foetal blood from the umbilical cord for stem cell preservation is permitted and now takes place fairly regulary. Potentially stem cell research has, as a goal, the in vitro production of body organs, and thus the notion of human cloning is not fictional. Section 57 prohibits reproductive cloning of human beings, but does allow therapeutic cloning using adult or umbilical cord stem cells. Any and all research relating to stem cells must be undertaken with ministerial consent. The applicant is required to document research for record purposes, and must have the consent of the donor of the stem cells or zygotes. Contraventions of this section, do not however, carry a harsh sanction.

7.2 Recommendations for regulating stem cell research in S.A.

As stem cell research becomes more prominent in S.A., more specific regulations may need to be put into place. These legislations should endeavour to be expansive as opposed to restrictive. However, stem cell research should be limited to research aimed at improving the quality of human life as opposed to genetically engineering human life. Stem Cell regulations should allow the use of embryonic stem cells procured under clinical conditions. All research should be conducted at confirmed research facilities and should be made publically available.


Stem cell research is full of potential. It has given, and continues to offer new hope to people suffering with diseases such as leukemia and vascular heart disease. In the future deaths associated with these diseases, amongst other such diseases, could be reduced to a minimum. As such it is important that legislation be in place that allows stem cell research to be conducted reasonably freely and safely. South Africa should also devote its efforts/ continue devoting its efforts to stem cell research.

There is much room in terms of the development of iPSCs that could bring stem cell research onto new levels entirely. This research could allow for the treatment of any number of diseases with adult autologous stem cells, essentially changing the nature of medicine.

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