Abstract

Background and Aims: Emerging evidence suggest that metabolic endoscopy with devices such as the intra-gastric balloon (IGB) may be valuable, besides bariatric surgery, in managing obesity and related non-alcoholic fatty liver disease (NAFLD). NAFLD ranges from hepatic steatosis through non-alcoholic steatohepatitis to fibrosis and cirrhosis. We sought to determine the efficacy of the IGB in obesity-related hepatic steatosis and related non-invasive indices along with changes in gut microbiota and nutritional patterns.

Materials and Methods: Thirty-three obese patients, body mass index (BMI) >30kg/m2, with hepatic steatosis were recruited for IGB treatment. Three patients withdrew early in the study. Of the remaining thirty, mean whole group BMI was 39.3±6kg/m2 and mean whole group weight was 110.5±18.5kg. Two patients failed to present for end-of-study assessments. On IGB removal at six months, paired baseline and end-of-study results were available for 28 patients. Anthropometric, nutritional data, blood and fecal samples were collected at baseline and at six months. Gut microbiota diversity was assessed by 16S RNA sequencing.

Results: On IGB removal, patients were sub-divided into those losing ≥10% of initial body weight (Group 1) and those losing <10% of initial bodyweight (Group 2). Group 1 had a significant reduction (p<0.05), in weight, BMI, waist circumference (WC), HOMA-IR, HbA1C, AST, GGT along with a non-significant reduction in ALT and NAFLD fibrosis score (p<0.08). Group 2 had a significant reduction in WC, p=0.02. Retrospective analyses between Group 1 and Group 2 showed no differences in baseline characteristics. At baseline, the mean estimated daily total energy intake (TEI) reported by the cohort was 6467.5±3413.6KJ, with estimated daily nutrient composition at approximately 51±52% carbohydrate (CHO), 19.3±5% protein, and 25.6±8.3 fat. Mean daily sugar intake was estimated at 97.8±135.7g. At final follow up, comparing Group 1 to Group 2, estimated daily TEI showed a non-significant reduction at 5550.9±2227.4 vs 8404.7± 1566.1 (p= 0.07) as did total fat intake(g) at 37.9±16.5 vs 67.5±61.7, p=0.08. There was between Group 1 and Group 2 however, a difference in estimated daily carbohydrate intake at 167±70.5 vs 248.3±141.6 (p=0.05) along with a difference in estimated daily sugar consumption, at 79.8 ±48g vs 137.3 ±88.6 (p=0.02). In Group 1, at final follow up, there was compared to baseline a significant reduction in CHO as a percentage of TEI, at 54.5±8.9 reduced to 49.1±6.4, p=0.04. The cohort bacterial community structure did not differ significantly at baseline but was mildly altered post-IGB and enriched with the genus Bacteroides. The microbiomes differed in the two groups post-IGB. Group 1 showed a decrease in Streptococcus, Rothia and Butyrivibrio, while Clostridium XI was enriched.

Conclusions: Metabolic endoscopy with IGB improves anthropometric indices in obese patients with hepatic steatosis. Indices associated with obesity-related hepatic steatosis were also reduced in patients losing ≥10% of initial body weight. These patients showed a significant reduction in carbohydrate consumption. The weight loss and lowered CHO consumption was accompanied by mild changes in the microbiome with enrichment of Clostridium XI in Group 1. The significance of these nutritional and microbiota changes is uncertain but warrants further investigation.