Human Resilience and the Gut Microbiome
Authors: Rusling Matthew , Johnson Joseph , Shoskes Aaron , Jie Chunfa , Yuan Lilian 
Published: June 2021

Objective

This project evaluated the relationship of gut microbiome composition of first year medical students and stress resilience over a period of 4 months. Our objective was to identify gut microbiome characteristics of individuals that showed long term stress resilience.

Methods

Students were voluntarily recruited and screened for lifestyle and environmental factors. Their degree of psychologic stress at 3 timepoints during the first semester was measured with Cohen's perceived stress scale and PHQ‐9 depression scores. Fecal samples were collected at the same time using uBiome home kits at participant convenience. Samples were processed by uBiome and amplified for the 16s V4 gene. Stress and depression scores were normalized and summed to produce a psychologic index score. These scores were used to identify what microbiome characteristics may be correlated to stress resiliency of susceptibility. Metagenomic workup was performed using QIIME, MetaComet, and R Studio.

Summary of results

Across phyla present in 100% of samples, none were independently correlated with psychologic scores using a linear model while Bacteroidete:Firmicute ratio showed a significant negative linear correlation with the psychologic index (Pearon's, p=0.05, R=−0.24). Phylogenetic assembly of participants by microbiome relatedness found that 100% of subjects who were resilient to stress across all timepoints (n=8) were phylogenetically clustered in adjacent positions, showing a high degree of temporal stability. Of participants who were not durably resilient to stress, only 62% of participants (n=8) showed microbiomes that were phylogenetically related across the same 4 month period. We identified 2,102 Operational Taxonomic Units (OTUs) which were unique to the durable resilience group and 94 OTUs which were unique to the susceptible group. Of the 4,794 observed OTUs, 6.1% (n=294) were significantly different between groups by Kruskal‐Wallis before post‐test adjustment.

Conclusion

Findings of a correlation between an index accounting for stress and depression and the abundance of Bacteroidetes: Firmicutes, and a relationship between durable resiliency and microbiome stability support that the gut microbiome may play an important role in stress resilience at a time scale of 4 months. More research is indicated in this field to identify microbiome characteristics which are responsible for stress resilience. These may include the presence or absence of specific taxa or ratios between taxa, such as the Bacteroidete:Firmicute ratio. Eventually, a better understanding of the role of the gut microbiome in stress resilience may someday create opportunities to help those with conditions which are characterized by low stress resilience when faced with new challenges. We hope someday that exploration of the microbiome will produce actionable, clinically relevant opportunities.

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.