Neurological diseases >>>> The causes and mechanism of multiple sclerosis

The causes and mechanism of multiple sclerosis.

Multiple sclerosis is a chronic inflammatory disease of the nervous system associated with damage to the myelin layer of nerve fibers.

In the central nervous system there are cells - oligodendrocytes, which are responsible for the synthesis of myelin. In the cerebral cortex, the process of myelinesation lasts up to 45 years, and if you measure the concentration of myelin in the total mass of the brain (calculated for dry mass of the brain) of a person, then it is 35%.

Myelin forms the myelin sheaths of nerve fibers, which have many functions: insulating, supporting, barrier, trophic, transport, and also participate in the transmission of impulses. The main components of myelin are lipids and proteins. Lipids (phospholipids, glycolipids, steroids) make up about 80% of myelin.

Myelin is not an inert structure; it constantly exchanges its biochemical components with other elements of the nervous system. And that's why damage to the myelin layer disrupts the entire system.

The process of myelination of nerve fibers affects the ability to learn. There is such an enzyme cyclonucleotide-3-phosphohydrolase, the activity of which, according to scientists, begins even before birth (in the womb), and after a person is born, it increases in parallel with an increase in myelin deposition. This enzyme is considered as a marker of oligodendrocytes and myelin, that is, the process of myelination is judged by its amount. Deficiency of vitamin B6, deficiency of growth hormone and thyroid hormone also lead to a decrease in the activity of the above-mentioned enzyme, which causes hypomyelinisation (lack of myelin) and complicates the learning process.

There are many theories of the occurrence of multiple sclerosis (infectious, genetic, toxic, immunological, endocrine, vascular), but, according to the researchers, the pathology of the immune system plays a leading role in the development of the disease . And the factors that trigger this process are viruses (measles viruses, herpes simplex, mumps, adenoviruses, and others). Entering an organism with a genetic predisposition and a defect in immune regulation, viruses lead to the formation of anti-myelin antibodies, which leads to the destruction of myelin.

The main role in the demyelization process is assigned to T-lymphocytes (carrying certain components of the histocompatibility complex), they cause swelling and detachment of the myelin sheath. The role of cytokines has also been added , one group of which causes the process of demyelization (TNF-alpha, IFN-gamma, lymphotoxin-alpha, IL1, IL2, IL12), and another group of cytokines (IFN-alpha, IFN-beta, PSF-beta, IL4 , IL6, IL10) is considered mediators of remission of multiple sclerosis. Such processes in the body are defined as autoimmune.

The disease multiple sclerosis occurs, as a rule, at a young age (by 20-40 years). The prevalence of the disease is associated with a cold climate (according to statistical studies). Although many aspects of this disease are still not well understood, scientists have identified several signs that are characteristic of multiple sclerosis:

Nystagmus;
Chanted speech (slow and jerky);
Intentional tremor (tremor that is absent when the limbs are at rest, and sharply increases with movement);
Primary atrophy of the optic nerves;
Change in abdominal reflexes in the direction of their decrease or complete absence.

It can take six years from the moment the first sign of multiple sclerosis appears until such a diagnosis is made.

Early symptoms of multiple sclerosis can be short-term visual disturbances (retrobulbar neuritis) and atrophy of the temporal halves of the optic discs, motor dysfunctions (for example, pathology of extensor and flexion functions of muscles), sensory disorders (numbness, "creeping creeps"), sometimes in some patients trigeminal neuralgia.

Several factors have been identified that cause exacerbation of multiple sclerosis :

weather conditions (ambient temperature)
infections
stressful situations
hot baths
hot food

To date, research continues on the factors provoking the development of demyelizing processes, and a search is underway for genes responsible for the onset of multiple sclerosis.