Research shows that children with autism have different bacteria in their guts

A study looked into the bacteria that children with autism have in their gut and concluded it is in different concentrations than the bacteria found in children without autism.

Children with autism spectrum disorders (ASD) have significantly different concentrations of certain bacterial-produced chemicals, called metabolites, in their feces compared to children without ASD. This research, presented at the annual meeting of the American Society for Microbiology, provides further evidence that bacteria in the gut may be linked to autism.

"Most gut bacteria are beneficial, aiding food digestion, producing vitamins, and protecting against harmful bacteria. If left unchecked, however, harmful bacteria can excrete dangerous metabolites or disturb a balance in metabolites that can affect the gut and the rest of the body, including the brain," says Dae-Wook Kang of the Biodesign Institute of Arizona State University, an author on the study.

Increasing evidence suggests that children with ASD have altered gut bacteria. In order to identify possible microbial metabolites associated with ASD Kang and his colleagues looked for and compared the compounds in fecal samples from children with and without ASD. They found that children with ASD had significantly different concentrations of seven of the 50 compounds they identified.

"Most of the seven metabolites could play a role in the brain, working as neurotransmitters or controlling neurotransmitter biosynthesis," says Kang. "We suspect that gut microbes may alter levels of neurotransmitter-related metabolites affecting gut-to-brain communication and/or altering brain function."

Children with ASD had significantly lower levels of the metabolites homovanillate and N,N-dimethylglycine. Homovanillate is the breakdown product of dopamine (a major neurotransmitter), indicating an imbalance in dopamine catabolism (the breaking down in living organisms of more complex substances into simpler ones with the release of energy). N,N-dimethylglycine is a building block for proteins and neurotransmitters, and has been used to reduce symptoms of ASD and epileptic seizures.

The glutamine/glutamate ratio was significantly higher in children with ASD. Glutamine and glutamate are further metabolized to gamma-aminobutyric acid (GABA), an inhibitory neurotransmitter. An imbalance between glutamate and GABA transmission has been associated with ASD-like behaviors such as hyper-excitation.

Using next-generation sequencing technology, the researchers also were able to detect hundreds of unique bacterial species and confirmed that children with ASD harbored distinct and less diverse gut bacterial composition.

"Correlations between gut bacteria and neurotransmitter-related metabolites are stepping stones for a better understanding of the crosstalk between gut bacteria and autism, which may provide potential targets for diagnosis or treatment of neurological symptoms in children with ASD," says Kang.

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Study: Maternal infections increase child's autism risk

A study found that a pregnant woman with a bacterial infections diagnosed in the hospital had a higher risk of the child being diagnosed with autism.

Hospital-diagnosed maternal bacterial infections during pregnancy were associated with an increased risk of autism spectrum disorders in children, according to a Kaiser Permanente study published Dec. 23 in the Journal of Autism and Developmental Disorders.

The research contributes new evidence to a body of scientific literature on the role of infection in autism risk and points to areas for further examination.

The study included 407 children with autism and 2,075 matched children who did not have autism. The study included infants born between January 1995 and June 1999 who remained members of the Kaiser Permanente health plan for at least two years following birth.

"Though infections in pregnant women are fairly common, in this study most were not associated with an increased risk of autism," said Lisa A. Croen, PhD, research scientist with the Kaiser Permanente Division of Research and senior author of the study. "Only bacterial infections diagnosed in the hospital were associated with an increased risk."

"Infections diagnosed in a hospital setting were more common among mothers of children who developed an ASD compared with mothers of children who did not develop an ASD," Croen further explained.

Women with bacterial infections diagnosed during a hospitalization (including of the genitals, urinary tract and amniotic fluid) had a 58 percent greater risk of having a child with an ASD. While not very common in any of the mothers studied (1.5 percent of mothers of a child with ASD vs. 0.5 percent of mothers of a child without ASD), infections diagnosed during a hospitalization in the second trimester were associated with children having more than a three-fold increased risk of developing ASD.

"Infections diagnosed in an inpatient setting may represent more severe infections, and these were associated with increased risk of ASD," said Ousseny Zerbo, PhD, research fellow with the Kaiser Permanente Division of Research and the study's lead author.

While the mechanism for how maternal infections may influence autism risk has not been firmly established, Zerbo said animal tests have shown that immune-system responses to infections during pregnancy may influence the neurological development of the fetus.

"Our findings indicate that although most infections during pregnancy were not associated with autism in the child, there appears to be some increased risk for autism," Zerbo said. "It would be prudent for pregnant women to contact their doctor if they suspect an infection."

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Study: Gut Bacteria Levels Lower in Children with Autism

A study claims that children with autism have lower levels of bacteria in the gut which makes them more susceptible to harmful bacteria.

A link may exist between autism and bacteria in a child's digestive tract, a small new study suggests.

Researchers analyzed gut bacteria in fecal samples from 20 children with autism and 20 children without the disorder. The children with autism had significantly fewer types of gut bacteria, which potentially could make them more vulnerable to harmful bacteria.

The study also found that children with autism had significantly lower amounts of three types of important gut bacteria.

Autism, a neurodevelopmental disorder that can range from mild to severe, affects social and communication skills.

The new study appears July 3 in the journal PLoS One.

"One of the reasons we started addressing this topic is the fact that autistic children have a lot of [gastrointestinal] problems that can last into adulthood," study leader Rosa Krajmalnik-Brown, a researcher at Arizona State University's Biodesign Institute, said in a university news release. "Studies have shown that when we manage these problems, their behavior improves dramatically."

This type of research could lead to new ways to treat autism-associated gastrointestinal problems, and improve diagnosis, prevention and treatment of autism, the study authors said.

Previous research has shown that gut bacteria plays a role in a wide range of important functions, including digestion, controlling body weight, immune response regulation and the production of neurotransmitters that affect the brain and behavior.

Although this study showed a potential link between gut bacteria and autism, it did not prove a cause-and-effect relationship.

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Study links autism, intestinal bacteria levels

Editors note: I am interested in systemic comorbidities in autism. For many years, parents have reported GI symptoms in children with autism. Perhaps we are getting some reputable data on this topic? But for those living with autism I ask you to proceed with caution! There is a difference between association and causation. For instance, do children with Down syndrome get more ear infections? Yes. Does that mean that ear infections cause Down Syndrome? Obviously not. JR

Study links autism, intestinal bacteria levels

Researchers at Columbia may be making strides toward understanding the neurological disorder of autism–starting with, of all places, the intestine, according to a recent study.

Dr. Brent Williams, an associate research scientist from the Mailman School of Public Health, headed the study, which examined gastrointestinal disturbances in children with autism. Researchers discovered that children diagnosed with autism that suffer from gastrointestinal disturbances have heightened levels of Sutterella, a type of intestinal bacteria.

After examining intestinal biopsies from his patients, Williams found that Sutterella bacteria existed in more than half of the children who had been diagnosed with autism. In comparison, Sutterella was not found in any normally developing children that also had gastrointestinal, or GI, disturbances.

“There have been reports relating to the prevalence of GI disturbances in children with autism, and those reports have been somewhat inconsistent,” Williams said. “One of the questions that is important to look at is whether the molecular underpinnings of the GI symptoms differ between children with autism and typically developing children.”

Although the correlation between autism and gastrointestinal dysfunction has been explored before, “the link between gastrointestinal and central nervous system dysfunction remains unclear,” according to Mady Hornig, researcher and associate professor of epidemiology.

“Gastrointestinal complaints are a prominent cause of concern and distress among children with autism and their caregivers,” Hornig explained. “Our approach allows us to rigorously investigate whether specific clinical and molecular patterns in the gastrointestinal tract are associated with neuropsychiatric disease.”

Williams and Hornig both said that they plan to work on future studies that delve more deeply into the relationship between GI disturbances and autism.

“We are exploring larger prospective studies where we could control for many factors that could be playing a role in the specific changes,” Williams said. “There is much work to be done toward understanding the role Sutterella plays in autism.”

Hornig added that to test the strength of the correlation, she hopes to expand the research to sample from a larger pool of patients.

“If we saw a close correlation, we would have a better time in accessing a larger population because not everyone will have serious GI disorders to bring to colonoscopy,” she said. “We could study larger populations in a more rapid fashion.”

Read more: http://www.columbiaspectator.com/2012/01/24/study-links-autism-intestinal-bacteria-levels