| Fight against forgetfulness

First of all the bad news. Alzheimer's disease, with about 1.2 million patients and the growing number of cases of one of the major common diseases in Germany, continues to be an effective drug. Contrary to what we regularly hope for, we finally discover a substance capable of stopping or even reversing this devastating form of brain aging, which had up to now caused all drug candidates to fail at the moment of their admission. Recently, Biogen, which has been testing an active ingredient in anti-Alzheimer's therapy with the Japanese company Eisai since 2017, had to stop studying. The researchers spoke of a disaster.

It is still unclear why it is so difficult to act pharmacologically effective against the disease. It is perhaps the complexity of Alzheimer's disease that has hitherto prevented a breakthrough in the treatment of this disease. One of the triggers is the change in the concentration of two key neurotransmitters, acetylcholine and glutamate. While acetylcholine is present in patients receiving a dose that is too low, there is an excess of glutamate, which causes persistent excitation of the nerve cells and damages them accordingly. Protein deposits, called plaques, appear to play an important role, which deposits on nerve cells and disrupts their functioning. How exactly but all these factors interact, is not yet known.

Nevertheless, there is also good news. Although the molecular mechanisms are not yet sufficiently decoded, progress has been made at another level. The WHO recently released a comprehensive paper presenting new findings on the prevention of Alzheimer's disease risks. It presents a large number of instructions for action, classified according to scientific evidence, that is to say, the effects documented in the studies.

At the top is physical activity, the type of movement being less determinant than duration. Those who move at least 150 minutes a week, according to experts, significantly reduce the risk of illness. The positive effect of the sport is explained by the increased production of useful hormones and growth factors. Among the best known is a protein called BDNF, which acts in the hippocampus, a region playing an important role in the formation of memory.

According to WHO experts, blood pressure is another major influence on the brain aging process. Brain images of several hundred subjects under the age of 40 on average show: The brains of people with high blood pressure (about 140/90 mmHg) age faster. In magnetic resonance tomography, this looks like several years old brain, participating in the healthy study. The conclusions on smoking are equally clear. Prior to this, there were strong warnings that older smokers appeared to be more exposed to brain aging, which is related to the proven harmful effects of tobacco on blood vessels.

A study conducted in 2015 by the Karolinska Institutet in Finland and published in the American magazine Lancet has already demonstrated the positive influence of a healthy lifestyle on brain development. About 1300 people between the ages of 60 and 77 were observed, with a slightly increased risk of dementia due to health problems. Half of the participants lived in very good health for two years, with a diet low in sugar and fat, a low alcohol diet, endurance sports, bodybuilding exercises and relaxation exercises.

In the final cognitive performance tests, participants in this group scored significantly better than those in the control group who did not complete a special health program. The findings, say study leaders Miia Kivipelto and psychologist Krister Håkansson, "show that a healthier diet, physical activity, mental and social progress and control of potential cardiovascular problems increase cognitive performance. over 60. The years can improve significantly. "

In addition, a healthy lifestyle requires adequate sleep. Its important role in the prevention of Alzheimer's disease is known since 2013. That year, the Danish neurobiologist Maiken Nedergaard discovered the so-called glyphatic system of the brain. It is responsible for the removal of the waste protein mass, the brain produces about seven grams a day. If this cleaning system does not work properly, brain structures accumulate and increase the risk of neurodegenerative diseases such as Alzheimer's disease.

In collaboration with American researchers, Nedergaard and his team have identified a kind of passage from the blood vessels of the brain to the lymphatic system, through which proteins are transported. In the end, this has widened and the glyphatic system works very well. Apparently, this purification system is not only responsible for removing the beta-amyloid protein that forms the plaques, which obstruct the space between brain cells. There is even evidence that tau fibrils that accumulate in cells, small bundles of defective tau protein, are also washed away. Both structures are unique features of Alzheimer's disease.

Of course, medical research will continue to work hard to also tackle the disease at the molecular level. Currently, for example, the possibility of forming the body by means of a kind of vaccination on the effective elimination of the mentioned protein residues of beta-amyloid and dew is discussed. However, to date, it has not even been clarified whether plaques or fibrils are the trigger or simply a symptom of the disease.