Endogenous prostaglandins are physiological regulators of endocrine cells in the gastroduodenal mucosa of the rat

Neurotensin and Xenin Show Positive Correlations With Perceived Stress, Anxiety, Depressiveness and Eating Disorder Symptoms in Female Obese Patients

Objective

Neurotensin and xenin are two closely related anorexigenic neuropeptides synthesized in the small intestine that exert diverse peripheral and central functions. Both act via the neurotensin-1-receptor. In animal models of obesity reduced central concentrations of these peptides have been found. Dysregulations of the acute and chronic stress response are associated with development and maintenance of obesity. Until now, associations of both peptides with stress, anxiety, depressiveness, and eating disorder symptoms have not been investigated. The aim of the present study was to examine associations of neurotensin and xenin with these psychological characteristics under conditions of obesity.

Materials and Methods

From 2010 to 2016 we consecutively enrolled 160 inpatients (63 men and 97 women), admitted due to obesity and its mental and somatic comorbidities. Blood withdrawal und psychometric tests (PSQ-20, GAD-7, PHQ-9, and EDI-2) occurred within one week after admission. We measured levels of neurotensin and xenin in plasma by ELISA.

Results

Mean body mass index was 47.2 ± 9.5 kg/m². Concentrations of neurotensin and xenin positively correlated with each other (women: r = 0.788, p < 0.001; men: r = 0.731, p < 0.001) and did not significantly differ between sexes (p > 0.05). Women generally displayed higher psychometric values than men (PSQ-20: 58.2 ± 21.7 vs. 47.0 ± 20.8, p = 0.002; GAD-7: 9.7 ± 5.8 vs. 7.1 ± 5.3, p = 0.004; PHQ-9: 11.6 ± 6.6 vs. 8.8 ± 5.9, p = 0.008; EDI-2: 50.5 ± 12.8 vs. 39.7 ± 11.9, p < 0.001). Only women showed positive correlations of both neuropeptides with stress (neurotensin: r = 0.231, p = 0.023; xenin: r = 0.254, p = 0.013), anxiety (neurotensin: r = 0.265, p = 0.009; xenin: r = 0.257, p = 0.012), depressiveness (neurotensin: r = 0.281, p = 0.006; xenin: r = 0.241, p = 0.019) and eating disorder symptoms (neurotensin: r = 0.276, p = 0.007; xenin: r = 0.26, p = 0.011), whereas, men did not (p > 0.05).

Conclusion

Neurotensin and xenin plasma levels of female obese patients are positively correlated with perceived stress, anxiety, depressiveness, and eating disorder symptoms. These associations could be influenced by higher prevalence of mental disorders in women and by sex hormones. In men, no correlations were observed, which points toward a sex-dependent regulation.

Dual role of serotonin in the pathogenesis of indomethacin-induced small intestinal ulceration: pro-ulcerogenic action via 5-HT3 receptors and anti-ulcerogenic action via 5-HT4 receptors

Serotonin (5-HT) exerts multiple physiological functions not only in the central and peripheral nervous systems but also in the gastrointestinal tract, and these multiple functions are accounted for by a variety of 5-HT receptor subtypes. We investigated the role of 5-HT in the pathogenesis of indomethacin-induced intestinal lesions in mice, in relation to 5-HT receptor subtypes. A single oral administration of indomethacin (10 mg/kg) provoked damage in the small intestine of mice 24 h later, and this response was prevented by pretreatment with p-chlorophenylalanine (a 5-HT synthesis inhibitor). The administration of 5-HT3 receptor antagonists, such as ondansetron and ramosetron, dose-dependently reduced the severity of the intestinal lesions, whereas a high dose of GR113808 (a 5-HT4 receptor antagonist) significantly aggravated these lesions. In contrast, NAN-190 (a 5-HT1 receptor antagonist), ketanserin (a 5-HT2 receptor antagonist), and SB269970 (a 5-HT7 receptor antagonist) had no effect on these lesions. Mosapride (a 5-HT4 receptor agonist) significantly reduced the severity of indomethacin-induced intestinal lesions, and this protective effect was totally prevented by either GR113808 or methyllycaconitine (an α7-nicotinic acetylcholine receptor antagonist). Indomethacin increased the activity of myeloperoxidase and the expression of inducible nitric oxide synthase, inflammatory cytokines, and chemokines in the small intestine; these responses were significantly attenuated by ondansetron and mosapride. These findings suggest that endogenous 5-HT exerts a dual role in the pathogenesis of indomethacin-induced intestinal lesions: pro-ulcerogenic action via 5-HT3 receptors and anti-ulcerogenic action via 5-HT4 receptors, and the latter effect via 5-HT4 receptors may be mediated by activation of α7-nicotinic acetylcholine receptors.

Histopathological alterations in irritable bowel syndrome

Irritable bowel syndrome is a common disorder defined by a symptom complex including abdominal pain and altered bowel habit. The etiopathogenesis appears to be multifactorial and to involve altered gastrointestinal motor function, enhanced perception of visceral stimuli and psychosocial factors. More recently a role for mucosal immune activation has been suggested. Routine histologic examination reveals no mucosal abnormality in the majority of cases but quantitative histological, immunohistochemical and ultrastructural analyses reveal subtle morphologic changes involving lymphocytes, mast cells, enterochromaffin cells and enteric nerves. The recent appreciation of these changes has led to new hypotheses linking central and enteric nervous systems to immune processes. This review highlights the spectrum of morphologic changes that occur in irritable bowel syndrome, examines their relationship to the pathophysiology of irritable bowel syndrome and considers their relevance to daily pathology practice.

Distinctive clinical, psychological, and histological features of postinfective irritable bowel syndrome

OBJECTIVE

Irritable bowel syndrome after gastroenteritis is well recognized. Our aim was to determine whether postinfective IBS (PI-IBS) has histological or clinical features that are distinct from those of IBS patients with no history of preceding infection.

METHODS

A total of 75 consecutive IBS outpatients and 36 healthy control subjects completed a questionnaire detailing symptoms, mode of onset, and previous psychiatric history. All underwent a full diagnostic workup including rectal biopsy, which included immunostaining and quantification for lamina propria or intraepithelial T lymphocytes, serotonin-containing enterochromaffin (EC), and mast cells. Patients were divided according to onset of symptoms into PI-IBS (n = 23) or non-PI-IBS (n = 52) patients.

RESULTS

Diarrhea predominance occurred more frequently in PI-IBS (70%) than in non-PI-IBS (42%) patients (p = 0.03). A history of previous treatment for anxiety or depression was present in 26% of PI-IBS patients compared to 54% of non-PI-IBS (p = 0.02). Biopsy results for all patients were normal using conventional criteria; however, quantification revealed that PI-IBS showed increased EC cells compared to those of non-PI-IBS patients (p = 0.017) and controls (p = 0.02). Lamina propria T lymphocytes were increased in PI-IBS (p = 0.026) and non-PI-IBS (p = 0.011) patients compared to controls. Mast cells were increased in non-PI-IBS patients (p = 0.054) compared to controls.

CONCLUSIONS

Individuals with PI-IBS are a clinically distinct subgroup characterized by diarrheal symptoms, less psychiatric illness, and increased serotonin-containing EC cells compared to those with non-PI-IBS.

Isolated rat stomach ECL cells generate prostaglandin E(2) in response to interleukin-1 beta, tumor necrosis factor-alpha and bradykinin

The ECL cells control parietal cells by releasing histamine in their immediate vicinity. Gastrin and pituitary adenylate cyclase-activating peptide (PACAP) stimulate histamine secretion from isolated ECL cells, while somatostatin and galanin inhibit stimulated secretion. Prostaglandin E2 and related prostaglandins likewise suppress ECL-cell histamine secretion. Conceivably, that is how they inhibit acid secretion. In the present study, we examined if prostaglandin E2 can be generated by isolated ECL cells. Rat stomach ECL cells were purified (>90% purity) by counterflow elutriation and gradient centrifugation and cultured for 48 h. ECL cell stimulants (gastrin and PACAP) and inflammatory agents (interleukin-1 beta, tumor necrosis factor-alpha and bradykinin) were tested for their ability to induce prostaglandin E2 accumulation (24-h incubation), measured by radioimmunoassay. Gastrin and PACAP did not affect prostaglandin E2 accumulation but interleukin-1 beta (300 pg/ml), tumor necrosis factor-alpha (10 ng/ml) and bradykinin (1 microM) induced a 2- to 3-fold increase in the amount of prostaglandin E2 accumulated. While the combination of interleukin-1 beta and bradykinin induced a 9-fold increase, the combination interleukin-1 beta+tumor necrosis factor-alpha and bradykinin + tumor necrosis factor-alpha induced additive effects only. The combination of interleukin-1 beta + tumor necrosis factor-alpha + bradykinin did not induce a greater effect than interleukin-1 beta + bradykinin. The effect of interleukin-1 beta + bradykinin was abolished by adding 10 nM hydrocortisone (suppressing phospholipase A2 and cyclooxygenase) or 1 microM indomethacin (inhibiting cyclooxygenase). Incubating ECL cells in the presence of interleukin-1 beta+bradykinin for 24 h reduced their ability to secrete histamine in response to gastrin. The inhibitory effect was reversed by 1 microM indomethacin. Also, increasing the concentrations of hydrocortisone in the medium resulted in an enhanced gastrin-stimulated histamine secretion. Hence, the previously described acid-inhibiting effect of inflammatory agents may be explained by inhibition of ECL-cell histamine mobilization, consequent to enhanced formation of prostaglandin E2 by cells in the oxyntic mucosa, including the ECL cells themselves.