Stem cell therapies
Figure 4.1 – The segment of coding DNA that causes the disease is replaced by a healthy copy in gene therapy.
Regenerative medicine offers a potential alternative therapy through the use of neural stem cells. This treatment involves the harvesting and modification of neural stem cells in a laboratory, and then transplanting the cells into the brain (Kim, 2013). Once isolated and extracted from the brain, the stem cells will undergo gene
therapy to express rapid multiplication of cells that differentiate into nerve cells. As a result, net production of neuronal connections is established, hence countering the harmful effects of nerve cell degeneration.
One study researched into the plausibility of this therapy in Alzheimer’s d isease, the commonest form of dementia. This neurodegenerative disease is caused by both the clumping of beta-amyloid, a toxic protein that forms plaques, and the accumulation of tau proteins in neurones. Tau proteins become insoluble when oxidized through hyperphosphorylation caused by beta-amyloid aggregations (Naini, 2015). The insoluble proteins form complexes called neurofibrillary tangles (Figure 4.2), disruptions in the neurones that inhibits the flow of nutrients (Klamer, 2020). Consequently, neuronal death follows along with synaptic loss.
Figure 4.2 – Beta-amyloid plaques and neurofibrillary tangles form, causing neuronal degeneration.
Like all other neurodegenerative diseases, there are no current treatments that cure Alzheimer’s. One study suggests the use of inhibitor drugs that reduce enzymatic activity associated with beta-amyloid (Wagner, 2021). However, these drugs are highly
toxic and unsafe, and thus not suitable for regular administration. Alternative treatments reduce or prevent neuronal degradation instead of reversing nerve loss, another example of current medical practices only managing symptoms.
However, neural stem cell therapies have been tested in mice in which human stem cells were transplanted into mice with Alzheimer’s disease. Analysis concluded that the stem cells differentiated into immature neurones (Hayashi, 2020). Though there were no changes in levels of beta-amyloid or tau proteins, two tests indicated that the stem cells had achieved improved memory consolidation via building more neuronal connections. The neural stem cells had secreted neurotrophic factors and
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