ena-STUDY-Universita degli studi di Milano-17-02-2021-16:04:44:144-903
Higher bacterial DNAemia can affect the impact of a polyphenol-rich dietary pattern on biomarkers of intestinal permeability and cardiovascular disease risk in older subjects
Scope. Aging is characterized by increased systemic low-grade inflammation, altered gut microbiota composition and enhanced intestinal permeability (IP). The intake of polyphenol-rich (PR) foods is proposed as a promising strategy to positively affect the gut microbiota-immune system-intestinal barrier (IB) axis. In this context, the MaPLE project was designed to test the hypothesis that a PR dietary pattern may preserve and/or improve IB function in older people. Here, we tested the hypothesis that the dietary intervention might have affected the presence of bacterial factors in the bloodstream of the older volunteers participating in the MaPLE trial. Methods and results. We quantified the presence of bacterial DNA in blood by qPCR targeting the 16S rRNA gene (16S; bacterial DNAemia). Blood DNA was  taxonomically profiled via 16S sequencing. We found that higher blood 16S levels are associated to higher BMI and markers of IP, inflammation and dyslipidemia. Subjects with higher bacterial DNAemia could benefit more from the PR-dietary intervention as demonstrated by the reduction of the markers related to IP, inflammation and dyslipidemia. Finally, we found that the bacterial DNA detected in blood mostly belong to ?-Proteobacteria, whose abundance significantly decreased after the PR-diet in subjects with higher bacterial DNAemia at baseline.Conclusion. This study shows that the efficacy of the PR diet could depend on bacterial DNAemia. Bacterial DNAemia may be a relevant marker to evaluate in order to test the efficacy of dietary interventions based on PR-foods in the older populations.
Scope. Aging is characterized by increased systemic low-grade inflammation, altered gut microbiota composition and enhanced intestinal permeability (IP). The intake of polyphenol-rich (PR) foods is proposed as a promising strategy to positively affect the gut microbiota-immune system-intestinal barrier (IB) axis. In this context, the MaPLE project was designed to test the hypothesis that a PR dietary pattern may preserve and/or improve IB function in older people. Here, we tested the hypothesis that the dietary intervention might have affected the presence of bacterial factors in the bloodstream of the older volunteers participating in the MaPLE trial. Methods and results. We quantified the presence of bacterial DNA in blood by qPCR targeting the 16S rRNA gene (16S; bacterial DNAemia). Blood DNA was  taxonomically profiled via 16S sequencing. We found that higher blood 16S levels are associated to higher BMI and markers of IP, inflammation and dyslipidemia. Subjects with higher bacterial DNAemia could benefit more from the PR-dietary intervention as demonstrated by the reduction of the markers related to IP, inflammation and dyslipidemia. Finally, we found that the bacterial DNA detected in blood mostly belong to ?-Proteobacteria, whose abundance significantly decreased after the PR-diet in subjects with higher bacterial DNAemia at baseline.Conclusion. This study shows that the efficacy of the PR diet could depend on bacterial DNAemia. Bacterial DNAemia may be a relevant marker to evaluate in order to test the efficacy of dietary interventions based on PR-foods in the older populations.