Alzheimer's, the gene that protects against the disease discovered: how it works

Sometimes, there is news that offers a lot of hope. But they should be taken with a pinch of salt. Because from the simple reading of a scientific study, which also contains an indication of great importance, it can be difficult to move on to practical reality. Thus it is necessary to observe with great attention the study that appeared in Acta Neuropathologica which describes the identification of a gene capable of reduce the risk of developing Alzheimer's disease by up to 70%.

The observation is of great scientific importance, but in the short term it will hardly become the basis for changing anything in the approach to the disease. In short, it will take time to think about a practical use of this discovery. And above all, it cannot be imagined that this observation allows us to put up a “shield” for all the people destined to get sick. This is why it is important to continue to focus on classic prevention of cognitive impairment.

What happens in those who suffer from Alzheimer's and how many sufferers there are

Think of a fog that slowly envelops the brain and dampens the ability of cells to interact, taking away memories, affections and more generally memory. Here, through the progressive loss of neurons and their connections, Alzheimer's disease leads to cognitive decline, which occurs due to the accumulation of beta-amyloid protein, precisely this fog, which damages neurons. Also because it is not always, and not only, Alzheimer's disease that determines it. According to what the Istituto Superiore di Sanità (ISS) reports, more than one million people in Italy would be dealing with a more or less serious form of cognitive impairment. And they would be about 600,000 patients with true Alzheimer's disease.
Warning: do not make the mistake of considering that this condition only affects those who suffer from it. In some way, in fact, again based on what is reported on the ISS Epicentro portal, considering all the dementias there would be around three million subjects in our country who are involved in assisting those who are sick.

What the protective gene is and how it works

The genetic variant with protective activity is involved in the production of a particular component that comes into play in the formation of blood-brain barrier. This sort of “checkpoint”, like a real border crossing, has the task of preventing potentially harmful substances, viruses or bacteria from passing from the blood to the brain. In practice, therefore, the genetic variant that codes for the fibronectin (this is the name of the substance found in this form of biological “frontier”), would help to create aoptimal cleansing of the nervous systemthus promoting the improvement of the environment in which it operates.

The gene which can be considered one sort of protective “shield”. for the brain was identified by experts at Columbia University, analyzing the genetic heritage of approximately 11,000 people. But it's not enough. In addition to identifying the small stretch of DNA, scholars have also tried to evaluate what this could become a target for new therapies, capable of having an action similar to that of the gene itself and therefore of keeping the brain “clean” of beta-amyloid, a substance that accumulates, just like waste, progressively enveloping the neurons. Furthermore, fibronectin generally tends to increase significantly in subjects with Alzheimer's disease. The genetic variant that acts as a “shield” could prevent this accumulation. At the moment the studies have only been conducted on laboratory models. And the theory seems to hold up, giving rise to hope for a cure that certainly doesn't appear around the corner.

How important genetics are in Alzheimer's disease

Estimates say that on average 10% of cases Alzheimer's disease appears to have a specific genetic pathway. Above all, it should not be considered that forms of dementia of this type exclusively affect very elderly people. Or better: the risk appears associated with advancing agebut the identity card cannot be considered the only parameter to keep in mind.

In this sense, Amalia Cecilia Bruni, then President of SINdem (Italian Society of Neurology for Dementia), some time ago told how they exist, although very rare, juvenile forms of dementia (Young Onset Dementia or YOD). The prevalence of these forms increases with age: between 30 and 34 years there are 6 subjects out of 100,000, between 34 and 64 it rises to 119 out of 100,000 and reaches 853 out of 100,000 between 60 and 64 years of age”. Obviously, these forms can manifest themselves differently compared to classic pathologies of old age.

“The clinical pictures in these forms are predominantly atypicaloften with consequent psychiatric disorders risk of often being misdiagnosed – is the expert's opinion. A not insignificant amount has an important metabolic component such as Niemann Pick type C disease, a typically infantile form which however also has Late Onset forms which fall into YOD. The situation is different in late onset dementia, after the age of 65, even if the lengthening of life has made it possible to understand that even in this group there is a strong heterogeneity and that particular forms exist in the oldest-old (>80 years), identified only by neuropathological studies. Alzheimer's disease is certainly the most prevalent form of dementia, but identifying treatments, despite recent progress, is extremely difficult.”

The different Alzheimer's “diseases”.

Alzheimer's disease can begin as a biological process in the brain twenty or more years before the onset of the first symptoms. This is now known from studies conducted precisely on pre-symptomatic subjects carriers of genetic mutations. This is the big problem in terms of treatment: even establishing a therapy at the onset could prove to be a late measure since the onset of symptoms does not correspond to the true onset of the disease and it should be considered rather as the moment in which the brain is no longer able to compensate for the disease, a bit like the vessel that overflows when it has long been filled. The same expert explains how we are not at all certain that the picture that manifests itself in genetic Alzheimer's disease is the same as that seen in “sporadic” Alzheimer's disease. There would therefore be no Alzheimer's disease but it probably needs to be talked about Alzheimer's diseases (different for locations and type of aggregated proteins).

A mathematical formula for prevention

Let's go beyond genetics. The brain is a plastic structure in continuous evolution and modulation throughout life and is therefore sensitive to interventions that, even from the outside, can be reflected on genetics, metabolism and neural connections. In this sense, it can be proposed again a simple mathematical formula to remember: 12 times 40. This is useful information to prevent cognitive difficulties in old age, first of all Alzheimer's disease. If we manage to control with the right habits the elements that can potentially favor the onset of these disorders, in fact, we can reduce the risk of developing disorders of this type by up to 40 percent.

The 12 risk factors

The report comes from a document from the Lancet Commission on Dementia Prevention, Intervention and Care. Aside from the scientific complexity of the information, it is worth remembering the twelve risk factors on which we can act preventively: starting with high blood pressure, obesity, smoking, diabetes, poor movement, alcohol abuse. It goes through real medical elements, such as hearing loss, which is considered particularly significant so much so that in terms of statistical “weight” it becomes the element at the top of the ranking, followed by depression, head trauma and alcohol abuse. Finally, attention must be paid to thesocial sphere where people live: isolation, poor education and environmental pollution.
According to experts, not “feeling” as you should means significantly increasing the risks. Attention must also be paid topollution, even if the research to evaluate the correlation between the two elements was conducted mainly on animals. According to studies, in fact, exposure to particulate pollutants in the atmosphere accelerates neurodegenerative processes. And, as if that wasn't enough, the nitrogen dioxide son of exhaust pipes when in high concentrations it could be, according to science, associated with a greater risk of developing dementia.
Let's be clear: we are only talking about higher risks that would be better to counteract.