• Alzheimer’s disease is the most common cause of dementia in older people
  • The methods used in evaluation of this disease are quite expensive and not very accurate
  • Early detection of the disease using these biomarkers showed accuracy up to 94%

Introduction – Alzheimer’s disease is a neurodegenerative disease characterized by progressive brain damage (1). It is one of the main causes of dementia in the elderly (1). In addition to memory disorders, the disease is also characterized by impairment of intellect, emotional state, behaviors and other psychic functions (2). The disease was first described in 1906 by Dr. Alois Alzheimer, in whose honor also took the name (3).

Fig. 1. Brain damage due to Alzheimer’s disease. Image adapted from (5).

In the US, about 5.5 million people suffer from Alzheimer’s disease, of which 5.3 million are over the age of 65, and about 200,000 are younger known as early-onset Alzheimer’s disease (4). The leading cause of Alzheimer’s disease is still unknown today, but some scientists have concluded that genetic, environmental, and lifestyle factors influence the onset of the disease (5). Researchers believe that a major cause of Alzheimer’s disease is a malformation of some proteins (6). Studies in patients with this disease have noted the presence of an apolipoprotein E gene (APOE), especially APOE ε4, whose presence increases the risk for the onset of the disease at younger ages (6). Microscopic changes affecting the onset of this disease include the presence of a neurofibrillary patch, which disrupts the nutritional transport system between neurons, and the presence of beta-amyloid plaques which also have a toxic effect on neurons (7). Memory loss is the first symptom observed in these patients (8). As the disease progresses, problems arise in the areas of thinking, making decision, coherent judgment and other psychological symptoms such as depression, apathy, withdrawal, self-esteem, tendencies of asocial behavior, loss of confidence in others and other symptoms that make life difficult not only for the sufferers but also for those around them, especially the family (8).Since there is no medication that would fully cure patients with this disease, treatment consists of reducing symptoms (9). Nowadays acetylcholinesterase inhibitors, memantima and anti-psychotic drugs are used to relieve symptoms (9). Also important in the prognosis of the disease are the behavioral and cognitive psychotherapy, rehabilitation and family support as a very important factor (9).

Fig. 2. Pathological changes in the patient’s brain with Alzheimer’s disease. Image adapted from medlineplus.gov

Scientific Research – Scientists from US and UK have recently conducted a research into the detection of Alzheimer’s disease using several biomarkers that target both beta-amyloid and tau (10). The analysis proved to be quite accurate in patients who had the APOE genotype and directly determined cerebral beta amyloid status (11). So far, PET amyloid assay has been shown to be effective in this regard, but given that the cost of this assay is quite high, researchers from the University of Gothenburg in Sweden analyzed the plasma Aβ42 / 40 ratio, concluding that the accuracy of this analysis was many times higher than the methods used before (12). Researcher Sid O’Bryan, a professor at the University of North Texas, in recent scientific reports cited that the discovery of these biomarkers primarily would help screening for this disease and then diagnose it (13). The scientists used another method based on Thioflavin T, which in principle represents fluorescence analysis of this molecule, as a potential early indicator in detecting Alzheimer’s disease (14). In addition to these researching’s, another method targeting astrocytes has been explored, in particular glial fibrillary acidic protein (GFAP), the level of which after analysis was significantly elevated in patients with this disease (15). The use of these methods has increased the accuracy of disease detection to 94% compared to the methods before (16).

Conclusions – knowing that Alzheimer’s is a very serious disease, the use of these biomarkers will enable not only the early stages of the disease to be diagnosed, but also to analyze the disease at a very low cost compared to other methods, but even more importantly at a fairly high accuracy.

COPYRIGHT: This article is the property of We Speak Science, a non-profit institution co-founded by Dr. Detina Zalli and Dr. Argita Zalli. The article is written by Driton Bajrami, University of Prishtina, Kosovo.

References:

  1. Allan H. Ropper, Martin A. Samuels, Joshua P. Klein (2014). Adams and Victor’s Ideas of Neurology, 10th McGraw-Hill Schooling
  2. https://www.alz.org/alzheimers-dementia/what-is-alzheimers
  3. https://www.alzheimers.org.uk/about-dementia/types-dementia/alzheimers-disease
  4. https://alzheimersnewstoday.com/alzheimers-disease-statistics/
  5. https://www.nia.nih.gov/health/alzheimers-disease-fact-sheet#causes
  6. https://www.nhs.uk/conditions/alzheimers-disease/causes/
  7. https://www.webmd.com/alzheimers/guide/alzheimers-causes-risk-factors
  8. https://www.mayoclinic.org/diseases-conditions/alzheimers-disease/symptoms-causes/syc-20350447
  9. https://www.alzheimersresearchuk.org/about-dementia/helpful-information/treatments-available/
  10. https://n.neurology.org/content/early/2019/08/01/WNL.0000000000008080
  11. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6211654/
  12. https://www.medtechdive.com/news/roche-assay-identifies-alzheimers-biomarker-in-blood-samples/557543/
  13. https://www.medpagetoday.com/neurology/alzheimersdisease/81379
  14. https://www.sciencedirect.com/science/article/pii/S2352872915000962
  15. https://touchneurology.com/insight/advances-in-blood-based-biomarkers-for-alzheimers-disease/
  16. https://www.medscape.com/viewarticle/915785