sexta-feira, 29 de agosto de 2014

Artigo sobre micróbios e comportamento

Um artigo muito interessante, sobre a influencia dos micróbios em nosso organismo. Copio a parte do texto que faz referência ao autismo.

In people, a few researchers suspect gut microbes might contribute to autism. Children with autism appear to have different gut microbiomes than those who develop normally. The emerging theory about autism and gut flora has generated some excitement, but not been clearly demonstrated or accepted, says Eugene Rosenberg. Although scientists don’t agree on exactly what changes—different cohorts and study methods yield different results—they often see that certain bacterial families are increased or reduced in stools from kids with autism. Furthermore, autistic children often have gastrointestinal problems, such as constipation or diarrhea, because of a syndrome called “leaky gut” that allows substances to escape the intestines into the bloodstream.
In a study published in December, microbiologist Sarkis Mazmanian and neuroscientist Paul Patterson at the California Institute of Technology in Pasadena examined the gut microbes of a mouse model for autism, which exhibits leaky gut as well as core autism-like behaviors, such as repetitive actions and limited communication and socialization (7). When the researchers treated the animals with the probioticBacteroides fragilis, a beneficial bacterium, it corrected not only the leaky gut but also some of the abnormal behaviors.
Compared with control mice, the autism model mice had 46-times the normal amount of a molecule called 4-ethylphenyl sulfate (4-EPS), a predicted output of gut bacteria. It is also a close chemical relative of p-cresol, a metabolite found at relatively high concentrations in the urine of autistic children. Treatment with probiotics restored the 4-EPS levels of the autism model mice to normal, probably by fixing their leaky guts and keeping the 4-EPS in the intestine.
Moreover, treating healthy mice with 4-EPS resulted in anxious behaviors similar to those seen in the autism model: they were more easily startled and spent less of their time in the middle of an open space than untreated mice. Perhaps, Mazmanian speculates, people with autism have excess 4-EPS, or similar molecules, leaking into their bloodstream and reaching the brain, affecting their behavior. The researchers are now planning to look for elevated 4-EPS in the blood of children with autism. (...)

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