Gastroesophageal junction smooth muscle remodeling after endoluminal gastroplication

Endoluminal gastroplication (ELGP) is an endoscopic mucosal suturing procedure for the treatment of gastroesophageal reflux disease. The antireflux mechanism of the mucosal suture remains poorly understood. The aim of this study is to investigate any morphologic changes in the smooth muscle layer induced by the mucosal sutures placed at the gastroesophageal junction.

ELGPs were performed using endoscopic suturing devices with placement of two or three circumferential sutures within 2 cm of the squamocolumnar junction. Eight patients with subsequent symptom resolution underwent endoscopic ultrasound (EUS) to evaluate the muscularis propria layer at the gastroesophageal junction. A swine model was used for EUS and histopathologic correlation study. Six control and 15 ELGP pigs were evaluated with EUS and histological examination of the gastroesophageal junction smooth muscle layer.

Focal thickening of the muscularis propria layer near the suture region (2.3 +/- 0.4 mm vs 1.4 +/- 0.3 mm, p < 0.01) was found in eight patients with symptomatic resolution. In ELGP pigs, the smooth muscle layer thickness increased by 2.6 mm near the suture site by EUS. By histology, the total and circular smooth muscle layer thickness increased by 2.1 mm and 1.9 mm, respectively.

Focal thickening of smooth muscle layer occurs at the gastroesophageal junction after ELGP in patients with gastroesophageal reflux disease. This finding was reproduced in a swine model and localized hypertrophy was found to be entirely due to an increase in the circular smooth muscle layer.