Saturday, February 29, 2020

Amyloid Hypothesis of Alzheimer Disease

Alzheimer’s disease affects the brain as a result of a regenerative disorder. This then causes loss in memory, thinking and alteration in behavior patterns and is regarded as the largest cause of dementia cases. The patients who are suffering from this disease require the provision of services from resource rich health facilities (Pohanka, 2014). The most affected population is the elderly people although a small proportion of young people are also affected by Alzheimer’s disease. This paper therefore explores alzehaimers disease amyeloid hypothesis in respect to the progress towards the development of treatment options. The amyloid hypothesis argues that when the amyloid beta peptides occur in the brain tissues, they lead to the development of the Alzheimer’s disease. This peptide cause autosomal forms of mutations in three regions namely: presenelin 1, 2 and the amyeloid precursor proteins. The association between this disease and amyloid beta peptide was upon the examination of brain where plaques were found (Selkoe and Hardy, 2016). Therefore, the amyloid cascade provides an explanation to the process via which the Alzheimer’s disease occurs. These include the genetic causes via mutations, phenotypes and pathology as well as the risks involved. There have been therapeutic drugs produced to target this peptide so as to lower its levels of production. This is expected to cause a clearance in the amounts and levels of amyloid beta protein which in turn should reduce the aggregation of peptides to form plaques. However, it is not clear on the amount of the amyloid peptide which is found in the brain. Something that needs to be noted is that the amyloid beta peptides are the primary components of the neurotic plaques in the brain tissues of the patients who have Alzheimer’s disease. This is due to the fact that different parts of the brain can carry different amounts of the amyloid peptide and the Alzheimer’s disease is normally heterogeneous (Drachman, 2014). Another close association between this peptide and this disease is from the cloning of the gene which encodes beta amyloid precursor protein as well as its location in the chromosome number 21. Moreover, it has been found that Down’s syndrome leads to the neuropathology of Alzheimer’s disease. With time, the genetic mutations in the amyloids precursor protein have be found to be a key factor in the development of Alzheimer’s disease. Since the amyloid beta peptide has been found to be usual product of the metabolism in beta amyloid precursor protein in a person’s life, it can be meas ured by use of a culture medium, plasma and cerebrospinal fluid. This measures whether there are any abnormalities which result from the beta amyeloid precursor proteins (Morris et al., 2014). However, recently there have been objections raised against the amyloid hypothesis. One of the objections is that the number of amyloid deposits in the brain tissues does not correlate with the level of cognitive impairments that develops in a patient. In another way, the amyloid hypothesis brings objections since the neurotoxic effects of the amyloid peptide and the effects to the brain have not been studied in vivo. It is also evident that the soluble oligomers of amyloid peptide are responsible for the dysfunction in the brain as opposed the amyloid monomers in Alzheimer’s disease patients. These and many other objections support a reasoning that the neurodegeneration of the brain in Alzheimer’s disease is caused by the injury from some diffused oligomeric assemblage of misfolded proteins (Demetrius et al., 2015). As a result of this, the large polymeric aggregates make the inactive reservoirs which are equal to the neurotoxic assembly. On the other hand, the plaques in the brain do not necessarily indicate protection to the host. This is because the observation of these plaques in neurodegenerative diseases means that the reservoir of toxic proteins has occurred in the brain. Experiments involving transgenic mice in which the amyloid beta proteins were deposited in the brain did not indicate any loss in the cognitive abilities. This unexpected behavior by the transgenic mice could be due to differences in the species used, lack of human inflammation mediators and the short period of exposure of mice to the amyloid beta peptide. Since the Alzheimer’s disease is as a result of lack of balance between the deposition and the clearance of amyloid beta peptides, then there is a need to get treatment strategies for this disorder. One of the approaches would be the inhibition of either the beta or the gamma secretase enzymes which are crucial for the formation of beta amyloids and amyloid precursor proteins (Doody et al., 2014). For the beta secretase, there are some screening which is being done for a chemical compound to find out whether it can be able to bind on the active site of aspartyl protease and hence cross the blood brain barrier. For the gamma secretase, there are chemical compounds which have already been found but no clinical trials have been done on humans yet. However, it would be advisable to adopt more different treatment approached for the amyloid beta associated Alzheimer’s disease since the previously proposed strategies have some limitations (Karakaya et al., 2013). For instance a different approach that can be used would involve the use of immunization strategies. The most recommended immunization methods would involve the use of amyloid beta proteins in the cerebral so that they can lower the amounts of peptide clearance from the brain (Aisen and Vellas, 2013). A kind of different approach would involve the use of anti-inflammatory methods and drugs to aid in the clearance of the amyloid beta proteins in brain tissues. The use of the anti-inflammatory methods is recommendable because it has been found that as the amyloid proteins accumulate in brain tissues, the rate of inflammatory process increases. For a long period of time, the hypothesis concerning the association of amyloid beta proteins and the Alzheimer’s disease has been investigated. This calls for the development of therapeutic strategies based on the anti-amyloid beta peptides. In order to get treatment options for this disease. The treatment therapeutics needs to be closely based on the various characteristics that are observed in the amyloid peptides with respect to Alzheimer’s disease. By the adoption of various methods of treatment involving amyloid precursor protein gene cloning, the scientific world will find out whether there is an association between the amyloid beta protein hypothesis and the Alzheimer’s disease. Aisen, P.S. and Vellas, B., 2013. Passive immunotherapy for Alzheimer's disease: what have we learned, and where are we headed?. The journal of nutrition, health & aging, 17(1), p.49. Demetrius, L.A., Magistretti, P.J. and Pellerin, L., 2015. Alzheimer's disease: the amyloid hypothesis and the Inverse Warburg effect. Frontiers in physiology, 5, p.522. Doody, R.S., Thomas, R.G., Farlow, M., Iwatsubo, T., Vellas, B., Joffe, S., Kieburtz, K., Raman, R., Sun, X., Aisen, P.S. and Siemers, E., 2014. Phase 3 trials of solanezumab for mild-to-moderate Alzheimer's disease. New England Journal of Medicine, 370(4), pp.311-321. Drachman, D.A., 2014. The amyloid hypothesis, time to move on: Amyloid is the downstream result, not cause, of Alzheimer's disease. Alzheimer's & Dementia, 10(3), pp.372-380. Karakaya, T., Fußer, F., Schroder, J. and Pantel, J., 2013. Pharmacological treatment of mild cognitive impairment as a prodromal syndrome of Alzheimer's disease. Current neuropharmacology, 11(1), pp.102-108. Morris, G.P., Clark, I.A. and Vissel, B., 2014. Inconsistencies and controversies surrounding the amyloid hypothesis of Alzheimer's disease. Acta neuropathologica communications, 2(1), p.135. Pohanka, M., 2014. Alzheimer s disease and oxidative stress: a review. Current medicinal chemistry, 21(3), pp.356-364. Selkoe, D.J. and Hardy, J., 2016. The amyloid hypothesis of Alzheimer's disease at 25 years. EMBO molecular medicine, 8(6), pp.595-608.Trt

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