New research findings: Natural intestinal flora can trigger multiple sclerosis
Multiple sclerosis (MS) is the most common inflammatory disease in the central nervous system. The exact causes of the disease have so far been largely unclear. A team of researchers has now found evidence that human gut bacteria can trigger MS.
Causes of multiple sclerosis
According to experts, multiple sclerosis (MS) is the most common inflammatory disease of the central nervous system. The exact causes of the disease have not yet been clarified. It is believed that hereditary factors and environmental factors, among other things, lead to a malfunction of the immune system. German researchers also reported that specific coagulation factors could trigger MS. And an international team of scientists has now found evidence that human gut bacteria can trigger multiple sclerosis.
Despite intensive research, the disease is still considered to be incurable. Nevertheless, researchers are cautiously optimistic about the future. Thanks to new drugs, MS is becoming more and more manageable.
In addition, certain plant peptides can stop the course of MS, as scientists found.
According to research, multiple sclerosis can also be slowed down with proper nutrition.
And experts from various research institutions reported in the journal "Journal of Neurology, Neurosurgery and Psychiatry" that increased coffee consumption can reduce the risk of developing MS by up to 30 percent.
Further successes have also been achieved in researching the triggers of the disease.
Nerve stimuli are no longer passed on correctly
In autoimmune diseases such as multiple sclerosis, misdirected cells of the immune system attack the body's own cells in the brain and spinal cord.
The attack triggered by auto-aggressive T cells damages the affected nerve cells and leads to the breakdown of their covering layer. Cells die and nerve stimuli are no longer passed on correctly.
Every person has potentially autoaggressive T cells, but the cells are usually in their "sleep state" for life. In some people, however, the pathogenic potential of these cells is awakened - MS breaks out.
Scientists suspect the reason for this activation in a combination of genetics and environmental factors.
"We now know more than 200 genes that make people susceptible to MS," explains Hartmut Wekerle from the Max Planck Institute for Neurobiology in a message.
"In order for the outbreak to occur, however, a trigger is needed that has previously been sought in the area of infections."
Triggers in the natural intestinal flora
Years ago, the expert and colleagues found that this trigger is probably to be found in the natural intestinal flora.
Now they were able to show that microorganisms in the gut of genetically modified, autoimmune mice were able to activate T cells, whereupon the animals developed an inflammation in the brain similar to that of human disease.
After animal experiments showed that intestinal bacteria can trigger multiple sclerosis, a large number of studies examined and compared the composition of the intestinal flora of healthy people and people with MS.
"However, the genetic diversity of these people and their intestinal flora made it very difficult to draw concrete conclusions from the results," said Wekerle.
"In addition, the presence of a certain microorganism in MS patients does not say anything about whether it actually takes on a function in the development of the disease. This can only be clarified with the help of animal experiments. "
The researchers now avoided these difficulties in a large cooperation project in which they closely linked clinical examinations and basic research.
Only one twin fell ill at a time
The basic idea of the cooperation project was to compare the intestinal flora of identical pairs of twins. In rare cases, MS patients have identical twin siblings, with in most of these cases only one twin suffering from multiple sclerosis while the other is healthy.
This is an indication that other than genetic factors are effective in the development of MS.
As part of the cooperation project, more than 50 identical twin pairs have been recruited across Germany, each of whom has a twin with multiple sclerosis.
Since each pair of twins is genetically identical, MS-relevant differences in the intestinal flora should be revealed in this way. Because the influence of the human genes on the intestinal flora can be neglected in the pairwise comparisons.
Functional role in T cell activation
Comparing the intestinal flora of the twins showed some interesting, albeit subtle, differences.
"However, it was really exciting when we vaccinated the germ-free, genetically modified mice with the respective human microbiomes," reports Guru Krishnamoorthy from the Max Planck Institute for Biochemistry.
Animals that received intestinal flora samples from the twins with MS suffered almost 100 percent from MS-like inflammation of the brain.
The studies confirmed for the first time that components of the intestinal flora of MS patients play a functional role in T cell activation and can therefore be a trigger for multiple sclerosis in humans.
Further limit the microorganisms in question
"Now it is important to further narrow down and examine the microorganisms in question," says Wekerle.
However, the physician points out that the examinations will undoubtedly take years and that it is still open whether and which diagnostic and therapeutic methods can result from this.
However, he does not believe in the "fecal transplantation" (stool transplantation) currently being discussed in the media by healthy people on MS patients as "quick help": "You never really know what's inside!"
In addition to the experts from the Max Planck Institutes for Neurobiology and for Biochemistry in Martinsried near Munich, there were also researchers from the Ludwig Maximilians University in Munich, the Max Planck Institute for Immunobiology and Epigenetics in Freiburg and the universities of California (San Francisco) and Münster involved in the scientific work. (ad)