"One Hundred Years of Solitude"—Alzheimer's Disease

Posted by beauty33 on January 24th, 2021

Nowadays, the world is still under the shadow of the COVID-19 pandemic. In the meantime, another "silent epidemic" continues to expand. In 2019, more than 35 million people worldwide suffered from this neurological disease, among whom are the aged over 60 years old. Although it is not as infectious as the SARS-CoV-2, yet it is widespread around the world, impacting the patients, their families, communities, and the whole country seriously. After more than 15 years of expensive expenditure in this field, there are still limited R&D results, with extremely high challenges. It is Alzheimer's disease (AD), the leading cause of dementia in the elderly.

September 21st is World Alzheimer's Day, and 2020 is the 27th year. At least 50 million people worldwide are suffering from classified dementia, with one person diagnosed every 3 seconds on average, and about 60 to 70% are Alzheimer's disease. Because this disease is directly related to age, with the increasing global aging, the number of patients will climb to 12.5 billion in 2050.

Alzheimer's disease is like an eraser that clears brain memory. The patient gradually loses basic work and social skills, and then survival ability, and eventually falls into a world of chaos. So far there is no effective drug or treatment. AD seems to be a by-product of human life extension. Currently, researchers have a certain understanding of Alzheimer’s disease, and are investigating the causes, of which the mainstream include the genetic factors pathogenicity hypothesis, β-amyloid hypothesis, tau protein hypothesis, etc., which are not clearly confirmed, and also the corresponding treatment methods have no significant effect. 

In the latest study from the Technical University of Munich, the research team found that the clue to the impairment of learning and memory in AD patients is the "overactive" of neurons in the brain caused by the excitatory neurotransmitter glutamate. This article published in the "Science" magazine became the first study to reveal the mechanism of early cell dysfunction in Alzheimer's disease, which revealed that this pathological neuron is over-activated long before the memory disorder appears, which causes the brain neurons to continuously receive wrong signals, leading to impaired signal processing capabilities.

Glutamate is the essential chemical substance that helps transmit signals between neurons, and is responsible for activating and connecting neurons for signal transmission. Researchers found that in the synaptic clefts of overactive neurons, glutamate concentrations were high and lasted too long, which is caused by β-amyloid protein molecule that prevents glutamate from being transported out of the synaptic cleft. It starts when the β-amyloid molecule is in the early soluble medium period. That is to say, after the plaques are formed, it is already too late.

However, this research itself is still a conjecture. If the treatment is successful, it may be possible to reversely confirm this hypothesis.

Studies showed that although AD usually occurs in middle-aged and elderly people, the root cause may be traced back to early years. Unbalanced diet, irregular sleep, and other bad habits are the accomplices

Poor sleep is a hidden danger of Alzheimer's disease.

Recently, a study by the University of California, Berkeley, published in the "Current Biology" journal, found that healthy people with poor sleep quality accumulated more beta amyloid protein in the brain over a few years. In the four-year follow-up study, although none of the participants developed clinical symptoms, such as cognitive decline, the results showed that the participants with less deep sleep and more fragmented sleep had a change in the accumulation rate of beta amyloid in the brain over the next few years, which heralded the quiet occurrence of Alzheimer's disease.

"Ketogenic Mediterranean Diet", a new attempt to reduce the risk of Alzheimer's disease.

The onset of AD is also closely related to eating habits. Some studies show that the foods containing a lot of sugar, fat, and carbohydrates, such as noodles, bread, refined meats, and high-sugar beverages can accelerate brain degeneration and dementia, while high-salt foods can cause Phosphorylation of tau protein in the brain, which subsequently lead to the deposition of insoluble tau protein, and consequently cognitive impairment. The main feature of the Mediterranean diet is that it contains a variety of fish and olive oil that is rich in monounsaturated and polyunsaturated fatty acids. The ketogenic diet is a low-carb, moderate-protein, and high-fat diet.

In addition to lack of sleep and poor diet, people's mentality and psychological conditions are also related to the occurrence. A new study found that repetitive negative thoughts (RNT) and cognitive decline lead to the accumulation of two harmful proteins related to Alzheimer's disease. In other words, long-term bad mood and negative emotions will also accelerate the course of disease. Of course, causality can be very complicated. For example, a lack of social relationships and poor family relationships will bring negative emotions, which in turn cause bad living habits and corresponding cardiovascular and heart diseases.