Embryonic stem cells
Dilen Patel
ParkinsonÊs, AlzheimerÊs, diabetes, heart disease and cancer are a few of the many diseases that are currently untreatable and only their symptoms can be managed. Stem cells have the potential to treat many of these diseases, and also be used to regenerate organs reducing the need for transplants. Stem cells are cells located all around the body, and are undifferentiated. This means that they can divide and multiply into many different cells types in the body 1 . Furthermore, as is the case in many tissues, they act like an internal repair system, indefinitely multiplying to replace other cells. This is because when each stem cell divides, it either becomes another stem cell or has the potential to become another type of cell which is more specialised, such as liver cells and red blood cells. At present, three types of stem cells have been discovered and researched; embryonic stem cells, adult stem cells and umbilical stem cells. Research has proven that embryonic stem cells have the most potential as they can differentiate into any of the numerous different cell types, and are therefore said to be ÂpluripotentÊ. Whereas the other types of stem cells cannot differentiate as easily because they are found in specific organs or in the bone marrow and so are restricted to only the cells that function there. 2 Found in the inner cell mass of a blastocyst (3 to 5 day embryo), embryonic stem cells are removed and can be used in potentially any area of the body where specialization into tissues and cells is required. Once placed into the body, the embryonic stem cells can replace the damaged tissue which isnÊt carrying out the function required. Thus the impact of embryonic stem cells on 1 Stem Cells Basics: Introduction (2009) 2 What Are Stem Cells and What Are They Used For? (2010)
present and future medicine could be immense, as they could theoretically treat diseases which donÊt currently have a treatment. For example, in people suffering from type 1 diabetes, the cells that usually produce insulin are damaged by the immune system itself. However new research indicates that it may be possible to control the differentiation of human embryonic stem cells in a cell culture to develop cells that produce insulin. These cells could then be used in transplantation therapy to treat people with diabetes. 3 Embryonic stem cells have great potential to be used in transplantation therapy, as they can replace, generate and protect cells. For example, when treating spinal cord injuries, transplantation of stem cells repairs the damage by replacing the nerve cells that have died, generate new supporting cells that will reform the myelin sheath and stimulate the re-growth of damaged axons, and protecting the cells at the site of the injury by releasing substances such as growth factors and removing toxins. Advances in stem cell therapy are already taking place, for instance doctors at Moorfields Eye Hospital, London, carried out the worldÊs first human trial using embryonic stem cells to treat patients with StargardtÊs macular dystrophy. By taking healthy immature cells from a human embryo and developing them into cells found in the retina, doctors injected these cells into the diseased eye. After the surgery, structural evidence showed that the cells had attached to the eyeÊs membrane, and continued to survive throughout the study (16 weeks). The procedure was deemed 3 What Are the Potential Uses of Human Stem Cells and the Obstacles That Must Be Overcome before These Potential Will Be Realized? (2009)
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