Mucosal alterations after vertical banded Roux-en-Y gastric bypass for morbid obesity have not been clearly evaluated, since the excluded stomach is not easily reached by conventional endoscopy.
Aim: to analyze the mucosal alterations (proliferative rate, Ki-67; apoptosis, caspase-3; hormonal function, gastrin; and inflammatory infiltrate (CD3 and CD4) in the excluded stomach and in the gastric stump (functional pouch) after gastric bypass.
Methods: Double balloon endoscopy was performed in 35 patients who underwent vertical banded Roux-en-Y gastric bypass longer than 36 months. They underwent endoscopic examination with multiple biopsies of the gastric stump mucosa (four), of the excluded stomach mucosa (four at the body and four at the antrum) and duodenal biopsies (four). Gastric biopsies from 31 non-operated obese patients were utilized as controls. Endoscopic biopsies were cut from tissue blocks fixed in formalin and embedded in paraffin. Sections 4 µm thick were examined for expression of gastrin, Caspase-3, Ki-67, CD3 and CD4 using the streptavidin-biotin-peroxidase method. The grade of inflammation, atrophy and/or intestinal metaplasia, and the presence of Helicobacter pylori were recorded.
Results: Thirty patients (85.7%) were female and the mean age was 43.4 years-old (22 - 61 years-old). The mean post-operative time was 77.6 months (range 36 - 110 months). All patients had chronic gastritis in the bypassed stomach, with pangastritis in 33/35 (94.3%). Five cases (5/35, 14.3%) presented atrophy and four of them also had intestinal metaplasia. H. pylori was detected in 7/35 (20%) of the excluded stomach, and was positive in the antrum in all of them, and also positive in the body in four patients. The mean number of positive gastrin cells was 51.2 (13.6%) in the control group and 32.5 (9.2%) in the cases, p = 0.02. Ki-67 proliferative index in cases (body = 25.4%, antrum = 25.6%), was significantly higher than that in controls (body = 14.8% and antrum = 20.2%), p = 0.02 and 0.03. Caspase-3 immunoexpression was higher in the excluded stomach compared to the controls (45% vs. 18%), p = 0.02. The CD3+ T cell population contained 54% CD4+ (range 10-70%). There was no difference in studied immunoexpressions between the functional pouch and the controls for Caspase-3, Ki-67 and inflammatory infiltrate. There was no association between the immunoexpressions and the presence of Helicobacter pylori or histological alterations.
Conclusions: Cell proliferation and apoptosis are increased in the excluded stomach mucosa compared to the non-operated obese controls. Alterations in cell turnover in these conditions may be of relevance in long term follow up.