miércoles, 29 de enero de 2014
Clostridium perfringens toxin could trigger multiple sclerosis (MS)
Epsilon toxin produced by some strains of Clostridium perfringens can cause MS-like damage in the brain. MS is is generated by genetic and environmental factors but the exact environmental trigger is not known yet.
Pathogen effect The US Centers for Disease Control and Prevention (CDC) estimates that non-epsilon toxin producing C. perfringens strains cause nearly a million cases of foodborne illness each year. C. perfringens is commonly found on raw meat and poultry and some strains produce a toxin in the intestine that causes intestinal illnesses.
Multiple sclerosis is an inflammatory disease of the central nervous system characterized by blood brain barrier (BBB) permeability and demyelination, a process in which the insulating myelin sheaths of neurons are damaged.
This study provide evidence that supports epsilon toxin's ability to cause BBB permeability and show that epsilon toxin destroy the brain's myelin producing cells, oligodendrocytes; the same cells affected in MS lesions.
Type B strain found. Linden and her colleagues discovered C. perfringens type B (a strain that was not known to infect humans) in a 21-year-old woman experiencing a flare-up of her MS, in a study published in October last year (see below). Researchers tested samples of local foods for the presence of C. perfringens and the toxin gene. Of the 37 food samples, 13.5% were positive for bacteria and 2.7% were positive for the epsilon toxin gene.
Epsilon toxin. C. perfringens types B and D carry a gene (epsilon toxin) that emits a pro-toxin (a non-active precursor form of the toxin) which is turned into the epsilon toxin within intestines of grazing animals. The epsilon toxin travels through the blood to the brain, where it damages brain blood vessels and myelin, the insulation protecting neurons, resulting in MS-like symptoms in the animals. While the D subtype has only been found in two people, based on prior studies by other investigators, the B subtype had never been found in humans.
“This bacterium produces a toxin that we normally think humans never encounter. That we identified this bacterium in a human is important enough, but the fact that it is present in MS patients is truly significant because the toxin targets the exact tissues damaged during the acute MS disease process.
A high intake of dietary salt has been linked to amplifying and triggering autoimmune responses that can lead to MS, while high levels of Vitamin D may be associated with a lower risk of MS progression.