Background: Bariatric surgery is an effective intervention strategy in obesity, resulting in sustained weight loss and a reduction of comorbidities. Gastroplication, using the articulating circular endoscopic stapler, was recently introduced as a transoral bariatric technique. This procedure reduces gastric volume and induced 34.9 % of excess weight loss in the first year (Paulus et al. Gastrointest Endosc. 81(2):312-20, 3). The aim of the present study was to gain insight in the long-term effects and underlying mechanisms of gastroplication by investigating differences in the genome-wide gastric and duodenal transcriptome before and 1 year after intervention.

Methods: Ten morbidly obese patients (BMI 39.8 ± 0.9 kg/m² (mean ± SEM)) underwent gastroplication. Previous to the procedure and after 1 year, blood samples were taken, and mucosal biopsies were collected from the fundus, antrum and duodenum. Gene expression was measured using microarray analysis. Plasma adiponectin, HbA1c, IL-1β, IL-6, IL-7, TNF-α, IFN-γ, MCP-1, IL-8, TGF-1 and CRP levels were determined.

Results: Downregulation of inflammatory genes and gene sets was observed in the fundus and duodenum 1 year after surgery. Gene expression of ghrelin and its activating enzyme GOAT were downregulated in the upper gastrointestinal tract. Patients showed a reduction in plasma HbA1c levels (from 6.17 ± 0.51 to 5.32 ± 0.14 %, p = 0.004) and an increase of plasma adiponectin (from 16.87 ± 3.67 to 27.67 ± 5.92 μg/ml, p = 0.002).

Conclusions: Individuals undergoing gastroplication displayed a downregulation of inflammatory tone in the stomach and duodenum, which coincided with improved HbA1c and adiponectin levels. The reduction of inflammatory tone in the upper gastrointestinal tract may be a consequence of an improved metabolic health status or alternatively caused by the procedure itself.