THE IMPORTANCE OF SLEEP IS EVEN GREATER FOR MS'ERS
The reason why humans need sleep has intrigued scientists for centuries. We already know that a good night's sleep helps the body to replenish energy and ensures its smooth operation - but the biological process that happens during this period has only been studied recently.
A good night's sleep is able to renew the mind, relax the body and mind. A study published in The Journal of Neuroscience adds another reason to the list of benefits: sleep intensifies the production of myelin, a substance that surrounds and protects neurons in the central nervous system. "Our use of the brain while we are awake requires a period of rest. Many cognitive functions are compromised if we stay awake for long periods of time, attention, memory, mood still going through. They can only be repaired if, in fact, you fall asleep" explains neuroscientist Chiara Cirelli, a researcher at the University of Wisconsin, United States of America, study coordinator.
The observations were made in experiments with mice. The data obtained, indicated that the rate of production of the cells that creates myelin, oligodendrocytes, doubled as they fell asleep. Despite knowing that many genes are activated during sleep - like growth hormones - scientists still do not know the impact on the rest responsible for the production of white matter cells. "Now, it is clear that the way other cells operate in our nervous system will also change significantly if we are asleep or awake," explains the expert.
The ability to learn and gain new skills are precisely controlled by myelin, which acts as an insulator in an electric circuit. It ensures that the impulses are transmitted quickly from one cell to another, and can transmit a signal in with a speed of 100 meters per second (as fast as a Formula 1 car) speed. The development of oligodendrocytes is initiated during the second trimester of gestation, shortly after the development of the majority of neurons, it continues during birth and and into adulthood. Without the myelin sheath, however, the neurons are exposed, and the transmission of nerve impulses is compromised. "Short circuits" or failure of the transmission of impulses may also happen.
This is what happens with carriers of diseases such as multiple sclerosis. In this disease, the degradation of white substance can cause a range of physical and cognitive impairments, such as muscle weakness, tingling, or numbness in the face, arms and legs, incoordination, memory problems, imbalance, urinary incontinence, among others. The demyelination, however, does not occur homogeneously, but focuses primarily located in the sensory and motor areas.
The myelin attacks happen because of a genetic fault in the immune system - responsible for protecting the human body against an intruder agent such as a virus or bacterium - which, for reasons yet unknown, next attacks the white substance. The central nervous system has the ability to reverse, to some extent, the degeneration of myelin, but with the progression of the attacks the white substance of this mechanism loses power.
US researchers may offer new avenues in the treatment of multiple sclerosis. According to the study, the highest production of oligodendrocytes occurred during the deepest stage of sleep, REM (rapid eye movement, associated with the dream period). In contrast, when rats were forced to stay awake, there was a decrease in this rate. These structures are responsible for synthesizing and maintaining the myelin.
"In the inflammatory phase of autoimmune diseases affecting the central and peripheral or in the case of very intense and persistent nervous system demyelination, there is no chance of recovery with the drugs currently available," says neurologist Charles Tauil, Medical, Hospital de Base de Brasília .
The next step is to analyze the researchers production rates of oligodendrocytes in humans, in particular in those affected by multiple sclerosis. The suspicion is that sleep deprivation may worsen some symptoms of the disease. In addition, the team of Chiara Cirelli wishes to examine whether lack of sleep, especially during adolescence, may generate long-term issues to the brain.
According to the US Center for Prevention and Control of Diseases, sleep deprivation can increase the risk of chronic diseases - including cardiovascular problems and diabetes - depression, besides triggering greater tendency to obesity. For sufferers of neurodegenerative diseases, rest is essential. "Sleep is a natural process of renewal and balance of neurotransmitters and neurohormones that act on areas of the nervous system and control fatigue. A good night of sleep is key, as well as exercise and proper diet," says Carlos Tauril.
"Depending on the stage, the areas that were demyelinated can be retrieved. The axons are surrounded by myelin sheath, which is produced by oligodendrocytes in the central nervous system and by Schwann cells in the peripheral nervous system. The inflammatory phase of autoimmune diseases affecting the central nervous system such as multiple sclerosis or peripheral nervous system, such as Guillain Barre syndrome, there is no chance of remyelination with the drugs currently available. If the is less damage, the nervous system can reconstruct itself and fix the damage. Some drug research, like antilingo, are promises for regenerative action of the white substance, while some drugs already available, such as fingolimod and natalizumab, indirectly act to protect the attack to the myelin. "Carlos Tauil neurologist.