Tissue TRPV1, ghrelin and vip levels in gastroduodenal mucosa of patients with morbid obesity

In this study, we planned to research association of morbid obesity with VIP (vasoactive intestinal peptide), TRPV1 (transient receptor potential vanilloid-1 channels) and ghrelin level in upper gastroduodenal mucosa, also with serum concentration of ghrelin. The study group was organized among patients whose BMI (body mass index) is more than 40 kg/m2 and who referred to endoscopy unit of gastroenterology department at Akdeniz University Medical School Hospital for pre-operative evaluation before obesity surgery or because of any other indication. Study group was consisted of 46 patients and all patient's upper GIS (gastrointestinal system) mucosal biopsies were performed. Control group was consisted of 20 patients whose BMI were between 18-25 kg/m2 and whose upper GIS mucosal biopsies were performed for any reason. All participants were met inclusion criterias. We studied serum ghrelin concentration and tissue VIP level by ELISA (Enzyme-Linked ImmunoSorn-bent Assay). We used immunohistochemical technics and antibodies to detect tissue ghrelin and TRPV1 levels. There were no statistically significant difference between groups in terms of age and sex. Serum ghrelin concentration were similar in two groups. There were no correlation between serum concentration and tissue level of ghrelin. There was no statistically significant difference in terms of tissue ghrelin level between groups. We also determined that tissue ghrelin level at upper GIS and serum ghrelin concentration don't affected by age, sex, diabetes mellitus (DM), hypertension (HT), proton pump inhibitors (PPI) and smoking. There was no statistically significant difference among fundus, antrum and duodenum in terms of tissue VIP level. But tissue VIP level was higher in study group and the difference was significant when we compared duodenal specimens. Tissue VIP level was lower in duodenal specimens than gastric specimens in control group but this difference didn't existed in the study group. Age, sex, DM, HT, PPI and smoking didn't couse any difference in tissue VIP level. Fundus chief cells, fundus parietal cells, fundus foveolar cells, antral mucus cells, antral foveolar cells, duodenal mucus cells, duodenal goblet cells and duodenal absorptive cells were evaluated in terms of TRPV1 tissue level. There was no statistically significant difference between study group and control group in terms of percentage of immunostained cells by antibody against TRPV1. There was statistically significant difference among cells according to immunostaining by TRPV1 antibody. Fundus parietal cells, antral foveolar and duodenal absorptive cells seems to have highest percentage of immunostaining in each tissue. We also detected that foveolar cells and mucus cells have different tissue TRPV1 level in different tissues. İmmunostaining by TRPV1 antibody were positively correlated with age and there was statistically significant difference between patients older than 45 years and younger than 45 years in terms of immunostaining by TRPV1 antibody in fundus chief cells, antral mucus cells and duodenal mucus cells. Percentage of immunostaining was higher in older group. Patients with HT had higher percentage of immunostaining by TRPV1 antibody in fundus chief cells and duodenal mucus cells. Patients with DM had higher percentage of immunostaining by TRPV1 antibody in duodenal mucus cells. Sex, PPI and smoking didn't couse any difference in terms of tissue TRPV1 level. In our study, we determined some changes in gastroduodenal mucosa tissue even if differences weren't statistically significant. In order to ascertain these physiopathological changes more comprehensive studies in humans are needed. Besides that, studies in that area are important not only because of additive knowledge about physiopathology of obesity but also because of additive knowledge in terms of improve new treatment strategies for obesity. Key words: Morbid Obesity, Fundus, Antrum, Duodenum, Ghrelin, Vasoactive Intestinal Peptide (VIP), TRPV1, Capsaicin