Compound Produced by Gut Bacteria May Increase Risk of Allergy, Asthma in Infants
A new study by researchers at the University of California, San Francisco (UCSF) shows that a molecule produced by microbes in the gut of infants may increase their risk for suffering from an allergy and asthma.
It is not abnormal to have bacteria in the gut. There are millions of these organisms in everyone’s gastrointestinal tract. One may only worry when those that produce harmful substances are present.
The study which was published recently in the journal Nature Microbiology showed that the presence of certain microbial genes in the gut of newborns may predispose them to allergies and asthma later in life. This is because they produce a particular substance that increases the risk of these health issues.
“We have discovered a specific bacterial lipid in the neonatal gut that promotes immune dysfunction associated with allergic asthma,” said Susan Lynch, a study lead author.
The researchers expressed hope that the finding may help with development of interventions that can assist in guarding against the diseases.
Increasing Allergy and Asthma Risks
It was shown in earlier studies by Lynch’s team that an abnormality in the gut microbes of newborns increases the risk of allergies by age two and asthma by age four.
They were able to identify a fatty molecule in high amounts in feces of some one-month-olds with unhealthy gut bacterial community. The compound, which they called 12,13-diHOME, impacted adversely on the number and activity of regulatory T cells. These are immune cells whose work it is to fight allergies and inflammation.
The researchers went ahead in the latest study to investigate whether this molecule could increase allergy and asthma risks in infants. For this purpose, they injected the identified molecule into mice gut.
It was observed that injection of 12,13-diHOME into the gut of mice lowered the count of T cells they have in their lungs. The molecule changed the function of these cells and other immune system cells at molecular level.
The scientists found that the concentration of the lipid or number of its bacterial gene copies is a predictor of likelihood of developing allergy or asthma later in life.
They made this finding using stool samples of 41 racially and ethnically diverse one-month-old babies in Detroit. The result was replicated using stool samples of another 50 one-month-old babies in San Francisco.
However, the researchers said that 12,13-diHOME is probably just one of numerous substances produced by gut microbes that might make infants more vulnerable to immune-related conditions.
Possible Interventions Against Early Childhood Immune Disorders
Authors of the study expressed hope that their findings may lead to development of interventions. Such may help to prevent early childhood disorders related to the gut bacterial community, such as allergies and asthma.
“This finding paves way for early-life gut microbiome interventions to prevent these diseases from developing,” Lynch said.
Sophia Levan, the lead researcher in the new study, said the researchers were confident about the results. They thought that the observed greater allergy and asthma risks may be generalized to a larger population. This is based on the fact that the results came from studying two diverse populations in clearly distinct cities.
The researchers plan to continue their investigations with a view to developing screening protocols that can help detect infants at greater risks, judging by the presence of the identified compound and others in stool. They aim to come up with interventions that could help against possible disorders as well.
Allergy, Asthma Risk Are Increased by Microbial Compound in Infant Gut | UC San Francisco (https://www.ucsf.edu/news/2019/07/414991/allergy-asthma-risk-are-increased-microbial-compound-infant-gut)
Newborn’s Gut Bacteria and Allergy, Asthma Risk (https://www.webmd.com/parenting/baby/news/20160913/makeup-of-germs-in-newborns-gut-may-triple-allergy-asthma-risk)