Dataset Information

Circulating bacterial signature is linked to metabolic disease and shifts with metabolic alleviation after bariatric surgery.

ABSTRACT:

Background

The microbiome has emerged as an environmental factor contributing to obesity and type 2 diabetes (T2D). Increasing evidence suggests links between circulating bacterial components (i.e., bacterial DNA), cardiometabolic disease, and blunted response to metabolic interventions. In this aspect, thorough next-generation sequencing-based and contaminant-aware approaches are lacking. To address this, we tested whether bacterial DNA could be amplified in the blood of subjects with obesity and high metabolic risk under strict experimental and analytical control and whether a putative bacterial signature is related to metabolic improvement after bariatric surgery.

Methods

Subjects undergoing bariatric surgery were recruited into sex- and BMI-matched subgroups with (n = 24) or without T2D (n = 24). Bacterial DNA in the blood was quantified and prokaryotic 16S rRNA gene amplicons were sequenced. A contaminant-aware approach was applied to derive a compositional microbial signature from bacterial sequences in all subjects at baseline and at 3 and 12 months after surgery. We modeled associations between bacterial load and composition with host metabolic and anthropometric markers. We further tested whether compositional shifts were related to weight loss response and T2D remission. Lastly, bacteria were visualized in blood samples using catalyzed reporter deposition (CARD)-fluorescence in situ hybridization (FISH).

Results

The contaminant-aware blood bacterial signature was associated with metabolic health. Based on bacterial phyla and genera detected in the blood samples, a metabolic syndrome classification index score was derived and shown to robustly classify subjects along their actual clinical group. T2D was characterized by decreased bacterial richness and loss of genera associated with improved metabolic health. Weight loss and metabolic improvement following bariatric surgery were associated with an early and stable increase of these genera in parallel with improvements in key cardiometabolic risk parameters. CARD-FISH allowed the detection of living bacteria in blood samples in obesity.

Conclusions

We show that the circulating bacterial signature reflects metabolic disease and its improvement after bariatric surgery. Our work provides contaminant-aware evidence for the presence of living bacteria in the blood and suggests a putative crosstalk between components of the blood and metabolism in metabolic health regulation.

SUBMITTER: Chakaroun RM

PROVIDER: S-EPMC8218394 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:BackgroundBariatric surgery is considered to be the most effective treatment option for weight reduction in obese patients. Abdominal obesity is frequently accompanied by metabolic syndrome (MS). Adipokines are cell signaling proteins that have direct impact upon the metabolic homeostasis. The purpose of this analysis was to evaluate the effect of bariatric surgery, including laparoscopic sleeve gastrectomy (LSG) and laparoscopic gastric bypass (LRYGB) on the adipokine levels and metabolic profile as well as MS and status of type 2 diabetes (T2D).MethodsWe analyzed anthropometric parameters, blood levels of adipokines, vitamins, lipids and inflammatory markers in 30 bariatric surgery patients with obesity of class II or III 1 month before and 1 year after surgery as well as in 60 obese patients from general practice (GP) and 15 patients with normal body mass (control).ResultsThe BMI was significantly higher among patients before surgery and GP patients in comparison to control and post-surgery patients. The levels of glucose, cholesterol and LDL-cholesterol, triglyceride and hs-CRP were the highest in patients before surgery but decreased significantly after surgery, while the level of HDL-cholesterol increased after surgery. The levels of adiponectin increased and that of leptin decreased after surgery. The significant difference in the concentration of resistin was revealed between LSG and LRYGB methods. The relationship between resistin and vitamin D was also found. The patients with MS and T2D displayed significantly greater reduction in lipid markers and adipokine levels than the rest of patients.ConclusionRemarkable changes in levels of adipokines after bariatric surgery appear like increase in adiponectin and decrease in leptin levels. Significant improvement in anthropometric parameters, metabolic and inflammatory markers occurs, suggesting high potential for reduction of metabolic syndrome and risk for type 2 diabetes. We have shown for the first time ever that level of vitamin D may be involved in resistin regulation.