Far from the gut but still relevant? Circulating bacterial signature is linked to metabolic disease and shifts with metabolic alleviation after bariatric surgery

Abstract

Objective: Increasing evidence suggests links between circulating bacterial components and cardiometabolic disease. Nevertheless, thorough next generation sequencing based and contaminant aware approaches are lacking. We hypothesized that blood bacterial signature is associated with the individual metabolic risk and outcome of bariatric surgery in patients with high metabolic burden. Design: Bacterial DNA in the blood was quantified and 16S rRNA gene amplicons were sequenced in bariatric surgery candidates recruited into sex and BMI matched subgroups with (n=24) or without T2D (n=24). A stringent experimental and bioinformatic contaminant aware approach was applied to derive a compositional microbial signature from bacterial sequences at baseline, three and twelve months post-bariatric surgery. Associations between bacterial load and composition and host metabolic state were modeled. Lastly, Catalyzed Reporter Deposition (CARD) - Fluorescence In Situ Hybridization (FISH) was employed to visualize bacteria in blood samples. Results: A metabolic syndrome classification score was derived based on bacterial phyla and genera detected in the blood, which robustly classified subjects along their actual clinical group. Blood bacterial signature in T2D was characterized by decreased bacterial richness and a loss of health-associated genera and was further impacted by medication. Weight loss and improvement of glucose tolerance following bariatric surgery were associated with an early and stable increase of these genera in parallel with improvements in key metabolic parameters. CARD-FISH allowed the detection of living bacteria in blood samples in obesity. Conclusions: Our work provides contaminant aware evidence for a putative crosstalk between bacterial components of the blood, metabolism and medication in metabolic health regulation.

Analysis of the blood bacterial composition of patients with acute coronary syndrome and chronic coronary syndrome

“…Even though chronic coronary syndrome groups had much lesser alpha diversity, a dysbiotic gut has been linked to autoimmune diseases, diabetes, metabolic syndrome, autism, and colorectal cancer, among other chronic disorders ( Mosca et al., 2016 ). Vascular stiffness and ( Menni et al., 2018 ), type 2 diabetes ( Chakaroun et al., 2021 ), have also been linked to a decrease in alpha diversity. According to recent research, chronic renal disease patients’ blood has less alpha diversity ( Shah et al., 2019 ), than patients with myocardial infarction ( Amar et al., 2019 ).…”