Fecal Microbiomes Distinguish Healthy and Food Allergic Twins

Research done in the US on pairs of twins has identified fecal microbes to potentially play a key role in distinguishing between healthy and food allergic twins.

This study was born out of previous research on fecal microbiota in infants. When fecal microbes were transplanted from healthy and food-allergic infants to germ-free mice, who don't possess a microbiota, the healthy infant microbiota was protective against the development of food allergies.

The project was a collaboration between Cathryn Nagler and Kari Nadeau. Nadeau had already been studying the epigenetics of food allergies. Fecal samples from 13 pairs of twins with and without food allergies, along with five pairs of twins where both had at least one food allergy, had been already collected by Nadeau. The sequencing of these samples was done in Nagler's lab.

Nagler states that "By studying twin pairs, we had the benefit of examining genetically identical individuals who grew up in the same environment, which allowed us to begin to parse out the influence of genetic and environmental factors."

She adds that metabolites give us clues about what bacteria are doing mechanistically to regulate the immune response. Biomarkers are desperately needed to understand the immunoregulatory function of intestinal bacteria.

In the study, 64 distinct sets of bacterial species and metabolites were identified that distinguish the healthy from the allergic twin groups. Most of these bacterial species belonged to the Clostridia class, which has been known to protect against food allergies. The diacylglycerol metabolic pathway and two specific bacteria named Phasacolarctobacterium faecium and Ruminococcus Bromii were also found to be enriched within the healthy twins. The presence of allergy-protective bacteria, presumably since birth, seemed to persist in adulthood even after lifestyle changes and separation.

"In our study, we harnessed the benefits of both high-throughput microbiome sequencing and metabolic profiling techniques and were able to nominate two specific species, each involved in distinct metabolite pathways, that can be prioritized as potential targets for future research and therapeutic interventions in food allergies," says first author Riyue Bao.

Nadeau says that even though a cause-and-effect relationship has not been established, an association between disease and health has been. The specific role the above bacteria play in food allergies will be a focal point in future studies.Source-Medindia