Alzheimer’s disease: yesterday, today and tomorrow

Alzheimer’s disease was officially recognised in 1911, but its symptoms were known way before its discovery. Nowadays, people are aware of many aspects of Alzheimer’s disease, however we don’t know everything, including the actual cure. New directions in scientific research  give hope to our future, but are they moving towards positive results? 

First diagnosis

In early 1907 Aloysius Alzheimer described for the first time the neurologic symptoms of Auguste Deter, a fifty-one-year-old woman who was hospitalised in the state asylum of Frankfurt. Doctor Alzheimer’s medical records have an historical value for the medical community as they represent the first neuropsychological characterisation of Alzheimer’s disease. After Auguste’s death, the doctor analyzed the woman’s brain through a microscopic examination and observed the presence of protein plaques and foldings, which soon became the distinctive features of the disease. Since 1911 both European and American medical communities have made use of these evaluations to diagnose Alzheimer’s disease.

Biology of the disease

Alzheimer’s disease is the most common form of dementia, which causes memory, thinking and behavioral problems. It is a neurodegenerative disease with a different development in each patient. In Italy, Alzheimer’s disease affects more than a million people, and the symptoms usually arise in people over sixty-five years old

The most affected part of the brain is the hippocampus: the anatomical location of learning ability. From a biological point of view, the disease is caused by the accumulation of proteins both inside and outside the neurons. The accumulation of protein plaques outside the cells is a common process in older brains. However, the presence of these specific protein plaques is not strictly linked to the onset of dementia or Alzheimer ’s disease. The plaques accumulating extracellularly consist of  great amounts of amyloid beta: a peptide that originates from the Amyloid Precursor Protein (APP). The accumulation of amyloid plaques around the cells disrupts the neural communication network causing the loss of brain function. Alzheimer’s disease is a combination of the development of amyloid plaques  and the accumulation of proteins (protein tau), which occurs inside the cell after the latter loses its physiological function. The intracellular accumulation of proteins is known as neurofibrillary tangles and they lead to severe malfunctioning or even death of neurons

Causes

The causes of Alzheimer’s disease remain unknown. In approximately 5-10% of the cases the origin is genetic, symptoms are inherited and are linked to the presence of alleles of three already known genes. In the remaining  90-95% of cases, the disease is not inherited, but the origin of the onset is unknown. What we do know is that there are risk factors which increase the probability of developing the disease. The main risk factor is age. Alzheimer’s is a disease affecting  mostly people over sixty-five years old and the majority are women. Other risk factors are familiarity with Alzheimer’s, cardiovascular diseases and pollution. Pollution is now being increasingly researched, and the gathered data seems to connect exposure to a polluted environment to the onset of Alzheimer’s disease. According to these studies the polluting particles reach the brain through the nose, causing the accumulation of molecules, including proteins, even in people under sixty-five years old. Some of these formations have been observed in the brains of children and newborns from the  most polluted cities in the world, for instance Mexico City. If the correlation is effective, it will be a great discovery to prevent the onset of Alzheimer’s disease and a further reason to take actions in favour of reducing pollution. 

Future prospects

As it has already been said, Alzheimer’s disease has still no cure. The pharmacological therapies that have been used so far  haven’t already shown any truly positive effects on the progress of the disease. The future medical strategies principally involve the importance of prevention, with the aim of eliminating the causes which increase the risk of onset and enhancing the early diagnosis of the disease.

In some cases there is encouraging news about this topic. A recent research project set up by a group of scientists of MIT in Boston studied the  gamma waves in brains of healthy patients and sufferers from Alzheimer’s disease. The results of the research show that people affected by Alzheimer’s experience a frequency reduction of some neural oscillations called gamma waves. As this phenomenon was also observed in model animals, the next step was to restore the normal frequency of the waves with pulsed light at a proper frequency: the first results were striking. Even though the explanation is not clear, the simulation of gamma waves made glial cells eliminate protein plaques. This process leads to an improvement of the nervous tissue and a regression of the disease. A further interesting element that emerges from the research is that the pulsed light works even if it is simply projected before the eyes. To observe positive effects (on rats), it only takes a screen that casts light at the right frequency.

It is  interesting, isn’t it? 

The research is at its very early stage, and it is too soon to celebrate. Nonetheless, there are high hopes to move forwards in the direction of discovering an effective therapy for an increasingly existing disease. If you want to dive more into the topic, check the links down below. On antropia.it IG profile, Alzheimer’s disease issue has already been discussed when the FDA authorized the commercialisation of Aducanumad; it has been a rather historical event since the last approval of a medication against Alzheimer ’s dates back to 2003. This choice raised many doubts, and the EMA has not yet authorized the medication in Europe, but why? We talk about that in this post.

Sources and insights

https://www.cdc.gov/aging/aginginfo/alzheimers.htm

https://www.wnycstudios.org/podcasts/radiolab/articles/bringing-gamma-back

https://www.cell.com/cell/pdf/S0092-8674(19)30163-1.pdf

https://www.bbc.com/future/article/20200519-alzheimers-can-flashing-lights-provide-a-new-treatment

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