Scientists Discovered New Multiple Sclerosis Protective Mechanism
A team of researchers led by Alexander Prat and Jorge Alvarez at the University Of Montreal Hospital Research Center were able to decode how the blood-brain barrier is able to prevent the penetration of immune system cells into the brain. The study was published in the Science journal and researchers empathize that this findings regarding the blood-brain-barrier can help them to understand which are the mechanisms used by the brain to achieve a natural defence against the aggression of the immune system (which occur in the case of multiple sclerosis).
Multiple sclerosis is a debilitating auto-immune disease of the central nervous system, with inability of the brain-blood barrier to restrict and to control the passage of immune system cells into the brain. The result of this penetration of immune cells into the brain is that neurons in the brain and in the spinal cord cannot realize effective connections between them, leading therefore to extensive and recurrent damage of the central nervous system. Damage of the central nervous system leads to the occurrence of specific symptoms of multiple sclerosis, which include numbness, paralysis, visual problems, difficulties in coordination, moving and in balance. In the end, multiple sclerosis will lead to a chronic clinical handicap. There is no known treatment for this debilitating disease which affects the central nervous system.
The brain-blood barrier is a metabolic and physical barrier that has an important role in preventing the passage of harmful and unwanted cells or molecules into the central nervous system. This barrier is formed by endothelial cells (cells that are lining the interior surface of the blood vessels), which bound tightly and astrocytes (cells of the nervous system that have an important role in the transmission of the electrical signals in the brain and spinal cord).
The researchers were able to demonstrate that astrocytes are secreting a protein that has an important role in the organization of the central nervous system, called Sonic hedgehog and the endothelial cells present on their surfaces Hedgehog receptors. This two cells have an important role in the proper formation of the brain-blood barrier, during embryonic development and in maintaining the integrity of this barrier during adulthood.
More important, the scientists were able to demonstrate, using animal and human brain cells, that Hedgehog pathway has an important role in decreasing the migration of immune system cells into the central nervous system and in decreasing the adhesion of this type of cells. This means that the Hedgehog pathway is helping the brain-blood barrier to prevent the penetration of immune cells into the brain realizing therefore an anti-inflammatory balance of the central nervous system, when subjected to a direct attack of the immune system.
With this findings, the researchers hope that in the near future they will realize a proper therapeutic approach that will able to control the migration of immune system cells into the brain, finding this way, an efficient treatment for patients suffering from multiple sclerosis.