Stem cell therapies
Case study 3 – neurodegenerative disease
Neurodegenerative diseases are given to the group of illnesses caused by the progressive degeneration or death of nerve cells. These conditions largely affect the elderly as approximately 7.1% of the population suffer from dementia in the UK (Alzheimer's, 2018). With an ageing population due to medical advancements extending life expectancies, neurodegenerative diseases are becoming more prevalent. Over 850,000 people are affected by a form of dementia, costing the British economy an estimated £17 billion per year to support treatment costs (MRC, 2021). Nevertheless, despite the demands, no treatments currently exist for curing the degeneration of nerve cells. This case study will revie w the potential of stem cell therapies’ ability to provide a treatment. The brain is the most complex structure as part of the human anatomy; it acts as the control centre for almost every process in the body, such as the regulation of core body temperature or controlling the senses. It is achieved through a network of 100 billion interconnected neurones, cells that send and receive motor commands and electric impulses (Sah, 2019). Neuronal connections coordinate activity and outputs of different sections of the brain. However, insufficient neuronal connections cause reduced brain activity, which, in turn, leads to neurodegenerative disease. Unfortunately, neurones are unable to self-renew except in the hippocampus and the striatum, where neural stem cells are situated (Weishaupt, 2016). Regardless of this, with age, neuronal degeneration increases, which will exceed the rate of nerve cell replacement, resulting in disease. At present, there are no solutions for treating nerve cell deficiencies. Some non-drug treatments have been developed such as talking therapies or cognitive behavioural therapy, in which verbal support is offered to keep the mind active (Alzheimer's, 2018). Alternatively, some drug treatments are routinely used to treat patients suffering from dementia such as donepezil, administered daily (Birks, 2018). This drug is an acetylcholinesterase inhibitor, which reduces the loss of chemical signals between nerve cells. This will improve common neurodegenerative disease symptoms such as memory loss. However, these treatments merely manage the symptoms as opposed to searching for a cure.. Due to the widespread effects of neurodegenerative disease, research is required to investigate a potential cure. One innovative field of research is cell replacement therapy (Lindvall, 2004). This entails restoring function lost by damage or disease by replacing damaged nerve cells with healthy cells. This approach of transplantation would allow rebuilding of connections between brain sectors, which would reverse the effects of neurodegenerative diseases. However, this technique has its limitations. Firstly, a requirement is the neurones being replaced must have relatively low specificity in function, so it could only apply to less severe cases of brain damage. Moreover, the transplanted nerves are derived from foetal tissue grafts. Along with the implied ethical issues of destroying a foetus, there would be a limited supply of nerve cells available for transplantation, resulting in implementation in fewer cases of degeneration. Another field of research is the highly experimental gene therapy (Hunt, 2008). This involves replacing genes linked to the disease with an alternative healthier copy (Figure 4.1). This process inactivates the expression of the faulty genes using genome mapping. However, a restriction of this therapy is the inability to treat progressed neurodegenerative diseases; there is no mechanism to reverse the neurone connection loss, thus invalidating its ability to treat neurodegenerative diseases.
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