Interplay between Gut and Immune system - Multiple Sclerosis is triggered by friendly bacteria residing in the gut

Gut flora consists of microorganisms that live in the digestive tracts and is the largest reservoir of human flora. The human body, consists of about 100 trillion cells, carries about ten times as many microorganisms in the intestines. The metabolic activities performed by these bacteria resemble those of an organ. It is estimated that these gut flora have around 100 times as many genes as there are in the human genome.

Bacteria make up most of the flora in the colon and up to 60% of the dry mass of feces, between 300 and 1000 different species live in the gut. The microorganisms perform a host of useful functions, such as fermenting unused energy substrates, training the immune system, preventing growth of harmful, pathogenic bacteria, regulating the development of the gut, producing vitamins for the host (such as biotin and vitamin K), and producing hormones to direct the host to store fats. However, in certain conditions, some species are thought to be capable of causing disease by producing infection or increasing cancer risk for the host.

Multiple Sclerosis
Multiple Sclerosis (MS) is an inflammatory disease in which the fatty myelin sheaths around the axons of the brain and spinal cord are damaged, leading to demyelination and scarring as well as a broad spectrum of signs and symptoms. Disease onset usually occurs in young adults, and it is more common in women. MS affects the ability of nerve cells in the brain and spinal cord to communicate with each other effectively. Most likely MS occurs as a result of some combination of genetic, environmental and infectious factors, and possibly other factors like vascular problems.

MS is triggered by friendly bacteria residing in the gut
Researchers at the Max Planck Institute of Neurobiology in Munich, Germany have found an astonishing evidence that suggests MS is triggered by natural intestinal flora, the so-called friendly bacteria that reside in the gut. They say the bacteria first activated the immune T-cells, then the B-cells, which resulted in an attack on the myelin layer in the brain, developing brain inflammation similar to MS. MS is an autoimmune disorder where the body’s own immune system attacks and damages the myelin sheath that insulates the axons which are like the “cabling” that connects nerve cells or neurons to one another.

They discovered this by allowing some of the genetically modified mice to continue with their normal gut bacteria intact, while removing the intestinal flora in the others and keeping them under sterile conditions.The mice that kept their gut bacteria developed MS-like symptoms.

But the mice that had their gut bacteria removed remained healthy, despite their genetic predisposition to MS. They also had fewer T-cells in their gut, their spleens produced fewer inflammatory substances like cytokines, and their B-cells produced few if any antibodies against myelin.

However, when they then inoculated these mice with normal gut flora, their T-cells and B-cells increased, as did their cytokine and antibody production, and they eventually developed symptoms and fell ill.

Senior researcher, Gurumoorthy Krishnamoorthy told, “It appears that the immune system is activated in two stages: to begin, the T cells in the lymph vessels of the intestinal tract become active and proliferate. Together with the surface proteins of the myelin layer, these then stimulate the B cells to form pathogenic antibodies. Both processes trigger inflammatory reactions in the brain which progressively destroy the myelin layer – a process that is very similar to the way multiple sclerosis develops in humans.”

Molecular mimicry is a possible explanation for autoimmune side effects of microorganism infections. Protein sequences from a particular microorganism are compared to known autoimmune immunogens. For diseases such as multiple sclerosis (MS), where the infectious agent is unknown, guesses to its identity are made. Mimics are assumed to be rare. This study takes a radically different approach. Reported sequences from all known human bacterial and viral agents were searched for autoimmune immunogen mimics. Three encephalitogenic peptides, whose autoimmune requirements have been studied extensively, were selected for comparison. Mimics were seen in a wide variety of organisms. For each immunogen, the mimics were found predominantly in nonpathogenic gut bacteria. Since the three immunogens used in this study are related to MS, it is suggested that a microorganism responsible for autoimmune activity in MS could be a normally occurring gut bacterium. This would explain many of the peculiar MS epidemiological data and why no infective agent has been identified for MS and supports recently found MS gut metabolism abnormalities.

lambyjay wrote:

Can immune suppression actaully extend ones life?