Weight loss with or without intragastric balloon causes divergent effects on ghrelin cell expression

Objective The mechanism of action of intragastric balloons in the treatment of obesity is not fully understood. One of the hypotheses is that balloons might have an effect on the fundus, the area of ghrelin production. Methods Participants were randomized to a 13‐week period of sham or balloon treatment followed by a 13‐week period of balloon therapy in everyone. Blood samples for ghrelin levels were taken in the fasting state and after a breakfast at the start, after 13 and 26 weeks. Biopsies for ghrelin cell immunohistochemistry were taken from the fundus at endoscopy. Results Seven participants entered the balloon–balloon (BB) group and 11 the sham–balloon (SB) group. Despite a considerable weight loss, a median −17.9 kg (interquartile ranges −23.8 to −0.5) in the BB group and −18.3 kg (−22.7 to −14.7) in the SB group, fasting ghrelin and meal‐induced ghrelin response did not change. In the SB group, the number of ghrelin cells increased significantly (p 0.001) from 110.6 (83.6–118.9) to 160.2 (128.5–223.0) while on sham treatment and returned to initial levels, 116.3 (91.7–146.9) (p 0.001), when they received their first balloon. No significant changes in ghrelin cell numbers were observed in the BB group. Conclusion In participants without a balloon, weight loss induced an increase in ghrelin cell numbers in the fundus, which was annulled by the subsequent placement of a balloon. The effect of a balloon might be explained by effects on ghrelin cell numbers or ghrelin cell activity.