Gender-specific protection of estrogen against gastric acid-induced duodenal injury: stimulation of duodenal mucosal bicarbonate secretion

Estrogen regulates duodenal glucose absorption by affecting estrogen receptor-α on glucose transporters

The mechanisms of estrogen in glucose metabolism are well established; however, its role in glucose absorption remains unclear. In this study, we investigated the effects of estrogen on glucose absorption in humans, mice, and SCBN intestinal epithelial cells. We first observed a correlation between estrogen and blood glucose in young women and found that glucose tolerance was significantly less in the premenstrual phase than in the preovulatory phase. Similarly, with decreased serum estradiol levels in ovariectomized mice, estrogen receptors alpha (ERα) and beta (ERβ) in the duodenum were reduced, and weight and abdominal fat increased significantly. The expression of sodium/glucose cotransporter 1 (SGLT1) and glucose transporter 2 (GLUT2) and glucose absorption in the duodenum decreased significantly. Estrogen significantly upregulated SGLT1 and GLUT2 expression in SCBN cells. Silencing of ERα, but not ERβ, reversed this trend, suggesting that ERα may be key to estrogen-regulating glucose transporters. A mechanistic study revealed that downstream, estrogen regulates the protein kinase C (PKC) pathway. Overall, our findings indicate that estrogen promotes glucose absorption, and estrogen and ERα deficiency can inhibit SGLT1 and GLUT2 expression through the PKC signaling pathway, thereby reducing glucose absorption.

In vivo and In silico evidence of the protective properties of carvacrol against experimentally-induced gastric ulcer: Implication of antioxidant, anti-inflammatory, and antiapoptotic mechanisms

Gastric ulcer is a serious disease that affects millions of individuals worldwide. Alcohol consumption is a major contributor to the disease pathogenesis and ethanol-induced ulcer in rats closely recapitulates the clinical pathology of ulcer. In this study, rats were pretreated with carvacrol (CAR,50 and 100 mg/kg, orally) 1 h before absolute ethanol administration to induce gastric ulcer. CAR prevented ethanol-induced increases in gastric volume and acidity while restored mucin content. The gastro-protective activity of CAR, particularly the higher dose (100 mg/kg), was further supported by histopathological examination, as manifested by reduced gastric lesions. Interestingly, oxidative stress is linked to early stages of ulcer development and progression. In this study, ethanol administration upregulated the levels of ROS-producing enzymes, NADPH oxidase homologs 1 and 4 (Nox1 and Nox4) and lipid peroxides while depleting the antioxidant defense mechanisms, including GSH, Glutathione Peroxidase (GPX) and catalase. Interestingly, these alterations were significantly ameliorated by CAR pretreatment. Additionally, CAR possesses anti-inflammatory and anti-apoptotic activities. Pretreatment with CAR blunted ethanol-induced increases in inflammatory cytokines (NF-κB and TNF-α) and rectified the apoptosis regulator (Bax/Bcl2 ratio) in gastric tissue. Moreover, the docking simulation of CAR illustrated good fitting and interactions with GPX, Nox1 and TNF-α through the formation of hydrogen and hydrophobic (pi-H) bonds with conservative amino acids, thus, further supporting the anti-inflammatory and antioxidant effects underlying the gastroprotective effects of CAR. In conclusion, this study elucidates, using in silico and in vivo models, that the gastroprotective activity of CAR is attributed, at least in part, to its mucin-secretagogue, antioxidative, anti-inflammatory, and anti-apoptotic mechanisms.

Divergent roles of estrogen receptor subtypes in regulating estrogen-modulated colonic ion transports and epithelial repair

Although it was described previously for estrogen (E2) regulation of intestinal epithelial Cl- and HCO3- secretion in sex difference, almost nothing is known about the roles of estrogen receptor (ER) subtypes in regulating E2-modulated epithelial ion transports and epithelial restitution. Here, we aimed to investigate ERα and ERβ subtypes in the regulation of E2-modulated colonic epithelial HCO3- and Cl- secretion and epithelial restitution. Through physiological and biochemical studies, in combination of genetic knockdown, we showed that ERα attenuated female colonic Cl- secretion but promoted Ca2+-dependent HCO3- secretion via store-operated calcium entry (SOCE) mechanism in mice. However, ERβ attenuated HCO3- secretion by inhibiting Ca2+via the SOCE and inhibiting cAMP via protein kinases. Moreover, ERα but not ERβ promoted epithelial cell restitution via SOCE/Ca2+ signaling. ERα also enhanced cyclin D1, proliferating cell nuclear antigen, and β-catenin expression in normal human colonic epithelial cells. All ERα-mediated biological effects could be attenuated by its selective antagonist and genetic knockdown. Finally, both ERα and ERβ were expressed in human colonic epithelial cells and mouse colonic tissues. We therefore conclude that E2 modulates complex colonic epithelial HCO3- and Cl- secretion via ER subtype-dependent mechanisms and that ERα is specifically responsible for colonic epithelial regeneration. This study provides novel insights into the molecular mechanisms of how ERα and ERβ subtypes orchestrate functional homeostasis of normal colonic epithelial cells.

Mortality and risk factors associated with peptic ulcer bleeding among adult inpatients of Damascus Hospital, Syria: A cross-sectional study

Peptic ulcer bleeding is associated with significant morbidity and mortality, while monitoring mortality is extremely beneficial to public health, and the latest estimates date back to 2010 for the Syrian population. This study aims to estimate the in-hospital mortality rate and risk factors associated with peptic ulcer bleeding among adult inpatients at Damascus Hospital, Syria. A cross-sectional study with systematic random sampling. Sample size (n) was calculated using the proportional equation: [n = Z2P (1 - P)/d2], with the following hypothesis: Z = 1.96 for the 95% confidence level, P = .253 for mortality in patients hospitalized with complicated peptic ulcers, a margin of error (d) = 0.05, 290 charts were reviewed, and the Chi-square test (χ2 test) was used for categorical variables, and the t test for continuous data. We reported the odds ratio in addition to mean and standard deviation with a 95% confidence. A P value less than .05 was considered statistically significant. Data were analyzed using a statistical package for the social sciences (SPSS). The mortality rate was 3.4%, and the mean age was 61.76 ± 16.02 years. The most frequent comorbidities were hypertension, diabetes mellitus, and ischemic heart disease. The most commonly used medications were NSAIDs, aspirin, and clopidogrel. 74 patients (25.52%) were using aspirin with no documented indication P < .01, odds ratio = 6.541, 95% CI [2.612-11.844]. There were 162 (56%) Smokers. Six patients (2.1%) suffered from recurrent bleeding, and 13 (4.5%) needed surgery. Raising awareness about the risks of using non-steroidal anti-inflammatory drugs may reduce the occurrence of peptic ulcers and, as a result, peptic ulcer complications. Larger, nationwide studies are needed to estimate the real mortality rate in complicated peptic ulcer patients in Syria. There is a lack of some critical data in the patients' charts, which necessitates action to correct.

Global, regional, and national burden of 10 digestive diseases in 204 countries and territories from 1990 to 2019

Background

Digestive diseases are very common worldwide and account for considerable health care use and expenditures. However, there are no global population-based estimates of the disease burden and temporal trend of digestive diseases.

Methods

Annual case numbers, age-standardized rates of prevalence, incidence, death, and disability-adjusted life-years (DALYs), and their estimated annual percentage changes (EAPCs) for digestive diseases between 1990 and 2019 were derived from the Global Burden of Disease, Injuries, and Risk Factors Study (GBD) 2019. The association between digestive disease burden and the sociodemographic index (SDI) was investigated. We also calculated DALYs attributable to risk factors that had evidence of causation with digestive diseases.

Results

Globally, in 2019, there were 88.99 million DALYs due to digestive diseases (3.51% of global DALYs). Digestive diseases were the 13th leading cause of DALYs globally in 2019. Global digestive disease DALYs were highest in the middle SDI quintile and in South Asia and were higher in males than females in 2019. Cirrhosis and other chronic liver diseases constituted the highest proportion of categorized digestive disease DALY burdens globally. From 1990 to 2019, the global age-standardized DALY rate of digestive diseases decreased from 1570.35 in 1990 to 1096.99 in 2019 per 1,00,000 population, with the EAPC being −1.32 (95% confidence interval [CI] −1.36 to −1.27). In 2019, the largest contributor to digestive disease DALYs at the global level, for both sexes, was alcohol use.

Conclusion

The results of this systematic analysis suggest that the global burden of digestive diseases is substantial and varies markedly according to age, sex, SDI, and geographical region. These results provide comprehensive and comparable estimates that can potentially inform efforts toward digestive disease control worldwide.

Association Between Serum Bicarbonate Levels and Prediabetes and Subclinical Inflammation in Young Healthy Adults: A Cross-sectional Study

PURPOSE

Low bicarbonate, a hallmark of metabolic acidosis is associated with various diseases. This study investigated associations between bicarbonate levels with prediabetes and subclinical inflammation among healthy young adults in Qatar.

PATIENTS AND METHODS

A cross-sectional study was carried out with 825 participants aged 18-40 years, devoid of any known comorbidities, using data from the Qatar Biobank. For each participant, blood samples were taken for measurements of bicarbonate, prediabetes, and subclinical inflammation biomarkers. Prediabetes was defined using HbA1c between 5.7 and 6.4% and subclinical inflammation was defined using monocyte to high density lipoprotein (HDL) cholesterol ratio (MHR). Associations between bicarbonate levels and the outcomes were analyzed using multivariable linear and logistic regression and then stratified by gender.

RESULTS

A total of 825 participants with mean age 29.2 years (5.9) of which 365 (44.2%) were males. After multivariable logistic regression, each unit increase in serum bicarbonate was associated with a 17% decreased risk of prediabetes (OR: 0.83, 95%CI: 0.70-0.99, p=0.034), in males but no association was observed for females. Similarly, after multivariable linear regression, a unit increase in serum bicarbonate was associated with a 0.18 unit decrease in MHR (beta -0.18, 95%CI: -0.29, -0.07, p=0.002), again with no association observed in females.

CONCLUSION

In a healthy young adult population, higher serum bicarbonate levels were inversely associated with both prediabetes and subclinical inflammation in males, but not in females.

Association between the Dietary Inflammatory Index and Gastric Disease Risk: Findings from a Korean Population-Based Cohort Study

Evidence suggests that diets with high pro-inflammatory potential may play a substantial role in the origin of gastric inflammation. This study aimed to examine the association between the energy-adjusted dietary inflammatory index (E-DIITM) and gastric diseases at baseline and after a mean follow-up of 7.4 years in a Korean population. A total of 144,196 participants from the Korean Genome and Epidemiology Study_Health Examination (KoGES_HEXA) cohort were included. E-DII scores were computed using a validated semi-quantitative food frequency questionnaire. Multivariate logistic regression and Cox proportional hazards regression were used to assess the association between the E-DII and gastric disease risk. In the prospective analysis, the risk of developing gastric disease was significantly increased among individuals in the highest quartile of E-DII compared to those in the lowest quartile (HRquartile4vs1 = 1.22; 95% CI = 1.08–1.38). Prospective analysis also showed an increased risk in the incidence of gastritis (HRquartile4vs1 = 1.19; 95% CI = 1.04–1.37), gastric ulcers (HRquartile4vs1 = 1.47; 95% CI = 1.16–1.85), and gastric and duodenal ulcers (HRquartile4vs1 = 1.46; 95% CI = 1.17–1.81) in the highest E-DII quartile compared to the lowest quartile. In the cross-sectional analysis, the E-DII score was not associated with the risk of gastric disease. Our results suggest that a pro-inflammatory diet, indicated by high E-DII scores, is prospectively associated with an increased risk of gastric diseases. These results highlight the significance of an anti-inflammatory diet in lowering the risk of gastric disease risk in the general population.

Relationship between Hormonal Modulation and Gastroprotective Activity of Malvidin and Cyanidin Chloride: In Vivo and In Silico Approach

Peptic ulcers are lesions that affect the gastrointestinal tract and that can be triggered by external factors such as alcohol use. This study investigated the gastroprotective role of two anthocyanidins, malvidin and cyanidin chloride, in an ethanol-induced gastric ulcer model in male and female mice (ovariectomized and supplemented with 17β-estradiol or not) and aimed to evaluate the effectiveness of anthocyanidins in preventing the formation of lesions and to identify the underlying mechanisms, while considering hormonal differences. Moreover, in silico comparative analysis was performed to predict the properties and biological behaviors of the molecules. We observed that the hormonal status did not interfere with the gastroprotective action of malvidin, although antioxidant mechanisms were modulated differently depending on sex. On the other hand, cyanidin showed gastroprotective activity at different doses, demonstrating that, for the same experimental model, there is a need to adjust the effective dose depending on sex. In silico analysis showed that, despite being structurally similar, the interaction with receptors and target proteins in this study (myeloperoxidase, superoxide dismutase, catalase, and reduced glutathione) differed between the two molecules, which explains the difference observed in in vivo treatments.

The global burden of peptic ulcer disease in 204 countries and territories from 1990 to 2019: a systematic analysis for the Global Burden of Disease Study 2019

BACKGROUND

Peptic ulcer disease is one of the most common diseases in gastroenterology clinics. However, reported data about the global burden of peptic ulcer disease are still scarce.

METHODS

This was a secondary data analysis on the prevalence, mortality and disability-adjusted life years (DALYs) due to peptic ulcer disease by sex, age group and socio-demographic index (SDI) at the global level in 21 regions and 204 countries and territories between 1990 and 2019 using the Global Burden of Diseases, Injuries, and Risk Factors Study 2019.

RESULTS

Globally, the prevalence cases of peptic ulcer disease increased from 6 434 103 (95% uncertainty interval 5 405 963 to 7 627 971) in 1990 to 8 090 476 (6 794 576 to 9 584 000) in 2019. However, the age-standardized prevalence rate decreased from 143.4 (120.5 to 170.2) per 100 000 population in 1990 to 99.4 (83.9 to 117.5) per 100 000 population in 2019. Moreover, the age-standardized mortality rate decreased by 59.4% (55.3 to 63.1) and the DALYs rate fell by 60.6% (56.8 to 63.9) from 1990 to 2019. Across SDI quintiles, low-middle and low SDI quintiles had the highest age-standardized prevalence, mortality and DALYs rates from 1990 to 2019.

CONCLUSION

The age-standardized prevalence, mortality and DALYs estimates of peptic ulcer disease decreased from 1990 to 2019 globally, but more efforts are needed for the prevention, early diagnosis and treatment of peptic ulcer disease in low SDI and low-middle SDI groups of countries.

Activation of G protein coupled estrogen receptor prevents chemotherapy-induced intestinal mucositis by inhibiting the DNA damage in crypt cell in an extracellular signal-regulated kinase 1- and 2- dependent manner

Chemotherapy-induced intestinal mucositis (CIM) is a common adverse reaction to antineoplastic treatment with few appropriate, specific interventions. We aimed to identify the role of the G protein coupled estrogen receptor (GPER) in CIM and its mechanism. Adult male C57BL/6 mice were intraperitoneally injected with 5-fluorouracil to establish the CIM model. The selective GPER agonist G-1 significantly inhibited weight loss and histological damage in CIM mice and restored mucosal barrier dysfunction, including improving the expression of ZO-1, increasing the number of goblet cells, and decreasing mucosal permeability. Moreover, G-1 treatment did not alter the antitumor effect of 5-fluorouracil. In the CIM model, G-1 therapy reduced the expression of proapoptotic protein and cyclin D1 and cyclin B1, reversed the changes in the number of TUNEL+ cells, Ki67+ and bromodeoxyuridine+ cells in crypts. The selective GPER antagonist G15 eliminated all of the above effects caused by G-1 on CIM, and application of G15 alone increased the severity of CIM. GPER was predominantly expressed in ileal crypts, and G-1 inhibited the DNA damage induced by 5-fluorouracil in vivo and vitro, as confirmed by the decrease in the number of γH2AX+ cells in the crypts and the comet assay results. Referring to the data from GEO dataset we verified GPER activation restored ERK1/2 activity in CIM and 5-fluorouracil-treated IEC-6 cells. Once the effects of G-1 on ERK1/2 activity were abolished with the ERK1/2 inhibitor PD0325901, the effects of G-1 on DNA damage both in vivo and in vitro were eliminated. Correspondingly, all of the manifestations of G-1 protection against CIM were inhibited by PD0325901, such as body weight and histological changes, the mucosal barrier, the apoptosis and proliferation of crypt cells. In conclusion, GPER activation prevents CIM by inhibiting crypt cell DNA damage in an ERK1/2-dependent manner, suggesting GPER might be a target preventing CIM.

A Nationwide Cohort Study Shows a Sex-Dependent Change in the Trend of Peptic Ulcer Bleeding Incidence in Korea between 2006 and 2015

Background/Aims

The incidence of peptic ulcer disease has decreased in past decades; however, the trends in peptic ulcer bleeding (PUB) are inconsistent among regions. This study aimed to investigate the trends in PUB incidence and the effect of risk factors on PUB in Korea.

Methods

The records of patients hospitalized with PUB from 2006 to 2015 were retrieved from the Korean National Health Insurance Service Database. Standardized incidences of PUB were calculated, and the clinical characteristics such as age, sex, Helicobacterpylori infection, drug exposure, comorbidities, and mortality were obtained.

Results

In total, 151,507 hospitalizations with PUB were identified. The overall annual hospitalization rate was 34.98 per 100,000 person-years. The incidence of PUB showed no significant change from 2006 to 2008 and decreased from 2008 to 2015, with an annual change of –2.7% (p<0.05); however, this change was only significant in men. The incidence of PUB was higher in men than in women between 40 and 70 years old and higher in women than in men older than 80 years. From 2006 to 2015, the H. pylori infection rate increased significantly in patients with PUB; however, there was no significant change in exposure to nonsteroidal anti-inflammatory drugs or other drugs that increase the risk of PUB.

Conclusions

Over the past decade, the incidence of PUB has decreased in a sex-specific manner. There has been a decreasing trend in the H. pylori infection rate and no change in exposure to drugs that increase the risk of PUB in Korea.

Estrogen Regulates Duodenal Calcium Absorption Through Differential Role of Estrogen Receptor on Calcium Transport Proteins

BACKGROUND AND AIMS

Intestinal calcium absorption from the diet plays important role in maintaining calcium homeostasis in the body. Estrogen exerts wide physiological and pathological effects in the human. Previous studies have shown that estrogen is involved in the intestinal calcium absorption. In this study, we made investigation on the mechanism of estrogen action on duodenal calcium absorption.

METHODS

The experiments were performed in mice, human, and human duodenal epithelial cells, SCBN cells. Murine duodenal calcium absorption was measured by using single pass perfusion of the duodenum in vivo. The calcium absorption of SCBN cells was evaluated by calcium imaging system. The expression of calcium transport proteins, transient receptor potential cation channel (TRPV6) and plasma membrane calcium pump (PMCA1b), in the duodenum or SCBN cells were analyzed by western blot.

RESULTS

The duodenal calcium absorption in ovariectomized mice was significantly decreased, compared with control female mice, which returned to control level after 17β-estradiol replacement treatment. Estrogen regulated the expressions of TRPV6 and PMCA1b in murine and human duodenal mucosae and SCBN cells. The further results from SCBN cells showed that 17β-estradiol regulated calcium influx through the respective effects of estrogen receptor (ER) ɑ and β on TRPV6 and PMCA1b.

CONCLUSION

Estrogen regulates duodenal calcium absorption through differential role of ERɑ and ERβ on duodenal epithelial cellular TRPV6 and PMCA1b. The study further elucidates the mechanism of estrogen on the regulation of intestinal calcium absorption.

Role of Daucus carota in Enhancing Antiulcer Profile of Pantoprazole in Experimental Animals

The carrot plant (Daucus carota) and its components are traditionally reported for the management of gastric ulcers. This study was performed to evaluate the role of carrot when administered concurrently with a conventional antiulcer treatment, pantoprazole, in alleviating gastric and duodenal ulcers in female experimental animals. The study involved standard animal models to determine the ulcer preventive effect using pylorus ligation, ethanol, and stress induced acute gastric ulcer models and duodenal ulcer models involving cysteamine. Acetic acid-induced chronic gastric ulcer and indomethacin-induced gastric ulcer models were used to evaluate the ulcer healing effect. Carrot fruit (500 mg/kg) and its co-administration with pantoprazole produced significant protection in an ethanol- and stress-induced acute gastric ulcer and cysteamine-induced duodenal ulcer. The healing of the acetic acid-induced chronic gastric ulcer was also augmented with this combination. Both total proteins and mucin contents were significantly increased in indomethacin-induced gastric ulcers. Similarly, in pylorus ligation, the pepsin content of gastric juice, total acidity, and free acidity were reduced. Overall, both ulcer preventive effects and ulcer healing properties of the pantoprazole were significantly enhanced in animals who received the co-administration of carrot fruit (500 mg/kg).

Advances in Ca2+ modulation of gastrointestinal anion secretion and its dysregulation in digestive disorders (Review)

Intracellular calcium (Ca²⁺) is a critical cell signaling component in gastrointestinal (GI) physiology. Cytosolic calcium ([Ca²⁺]_cyt), as a secondary messenger, controls GI epithelial fluid and ion transport, mucus and neuropeptide secretion, as well as synaptic transmission and motility. The key roles of Ca²⁺ signaling in other types of secretory cell (including those in the airways and salivary glands) are well known. However, its action in GI epithelial secretion and the underlying molecular mechanisms have remained to be fully elucidated. The present review focused on the role of [Ca²⁺]_cyt in GI epithelial anion secretion. Ca²⁺ signaling regulates the activities of ion channels and transporters involved in GI epithelial ion and fluid transport, including Cl^- channels, Ca²⁺-activated K⁺ channels, cystic fibrosis (CF) transmembrane conductance regulator and anion/HCO₃^- exchangers. Previous studies by the current researchers have focused on this field over several years, providing solid evidence that Ca²⁺ signaling has an important role in the regulation of GI epithelial anion secretion and uncovering underlying molecular mechanisms. The present review is largely based on previous studies by the current researchers and provides an overview of the currently known molecular mechanisms of GI epithelial anion secretion with an emphasis on Ca²⁺-mediated ion secretion and its dysregulation in GI disorders. In addition, previous studies by the current researchers demonstrated that different regulatory mechanisms are in place for GI epithelial HCO₃^- and Cl^- secretion. An increased understanding of the roles of Ca²⁺ signaling and its targets in GI anion secretion may lead to the development of novel strategies to inhibit GI diseases, including the enhancement of fluid secretion in CF and protection of the GI mucosa in ulcer diseases.

Roles of Up-Regulated Expression of ASIC3 in Sex Difference of Acid-Induced Duodenal HCO3 - Responses

Although the morbidity of ulcers is statistically higher in males than females, the mechanism of this difference remains unknown. Recent studies show that duodenal HCO3 - response to mucosal acidification is higher in females than males, and this may be a factor responsible for the sex difference in the mucosal protective mechanisms. In this article, we examined the duodenal HCO3 - responses to various stimuli in male and female rats, including estrogen, and reviewed the mechanisms responsible for the sex difference in the acid-induced HCO3 - secretion. Mucosal acidification was performed by exposing the duodenum to 10 mM HCl for 10 min. PGE2 was administered intravenously, while capsaicin was applied topically to the duodenum for 10 min. Tamoxifen was given s.c. 30 min before the acidification. Ovariectomy was performed 2 weeks before the experiments; half of the animals were given estrogen i.m. after the operation. Mucosal acidification increased duodenal HCO3 - secretion in male rats, and this response was inhibited by indomethacin and sensory deafferentation. Although no sex difference was found in HCO3 - responses to PGE2 and capsaicin, the response to acid was significantly greater in female than male rats. The different HCO3 - response to acid disappeared on ovariectomy, and this effect was totally reversed by the repeated administration of estrogen. The gene expression of ASIC3 in female rats was greater than in male rats and down-regulated by ovariectomy or tamoxifen treatment in an estradiol- dependent manner, while no sex difference was observed in TRPV1 and CFTR expressions. In conclusion, the acid-induced HCO3 - response is greater in female than male rats, and this phenomenon is not due to changes in PGE2 sensitivity or TRPV1/CFTR expressions but may be accounted for by increased expression of ASIC3 on sensory neurons, which is associated with the chronic influence of estrogen.

Can the gastric healing effect of Eugenia punicifolia be the same in male and female rats?

ETHNOPHARMACOLOGICAL RELEVANCE

Eugenia punicifolia (Kunth) DC. (Myrtaceae), an Amazonian medicinal plant known as "pedra-ume-caá," is popularly used as a natural remedy for inflammation, wounds, infections, diabetes, fever, and flu. Its anti-inflammatory, antinociceptive, and gastroprotective effects have already been characterized. We evaluated the gastric healing effect of the hydroalcoholic extract of the leaves of E. punicifolia (HEEP) in male and female Wistar rats against nonsteroidal anti-inflammatory drugs (NSAIDs) and ethanol.

MATERIALS AND METHODS

The healing effect of HEEP on the gastric mucosa of adult male and female Wistar rats was measured after the chronic application of aggressive factors such as NSAIDs or 80% ethanol. Male, and intact and ovariectomized (OVZ) female rats were treated with HEEP for two days (NSAIDs) or one, two, four, and six days (80% ethanol). The stomachs were analyzed macroscopically for ulcerative lesions (mm²), and the healing process was measured using biochemical analysis with anti-inflammatory and antioxidant parameters.

RESULTS

Macroscopic evaluation of the gastric mucosa showed that gastric lesions induced by NSAIDs were significantly healed (66%) and pro-inflammatory interleukin 5 cytokine level was decreased after two-day oral treatment with HEEP compared with those in the negative control group (p < 0.05). However, the gastric lesions induced by NSAIDs did not heal in HEEP-treated female rats (p > 0.05). In addition, four-day treatment with HEEP significantly healed the gastric lesions induced by ethanol in male and female rats (63% and 78%, respectively) compared to those of the negative control group (p < 0.05). However, the OVZ group required six days of HEEP treatment to heal gastric ulcers (67% compared to the control group). HEEP exerts the healing effect against ethanol by significantly reducing neutrophil infiltration into the gastric mucosa by decreasing myeloperoxidase activity in male and OVZ rats after four and six days of treatment, respectively (p < 0.05). Four-day treatment with HEEP also increased the level of a non-enzymatic antioxidant, reduced glutathione in intact females compared to that of the negative control group (p < 0.05).

CONCLUSION

These findings indicated that HEEP was effective in promoting the healing of gastric ulcers induced by NSAIDs or ethanol. The gastric healing effects of this extract could be affected by female sex hormone interference; in future, comprehensive studies should be performed by considering sex differences.

Intracrine Regulation of Estrogen and Other Sex Steroid Levels in Endometrium and Non-gynecological Tissues; Pathology, Physiology, and Drug Discovery

Our understanding of the intracrine (or local) regulation of estrogen and other steroid synthesis and degradation expanded in the last decades, also thanks to recent technological advances in chromatography mass-spectrometry. Estrogen responsive tissues and organs are not passive receivers of the pool of steroids present in the blood but they can actively modify the intra-tissue steroid concentrations. This allows fine-tuning the exposure of responsive tissues and organs to estrogens and other steroids in order to best respond to the physiological needs of each specific organ. Deviations in such intracrine control can lead to unbalanced steroid hormone exposure and disturbances. Through a systematic bibliographic search on the expression of the intracrine enzymes in various tissues, this review gives an up-to-date view of the intracrine estrogen metabolisms, and to a lesser extent that of progestogens and androgens, in the lower female genital tract, including the physiological control of endometrial functions, receptivity, menopausal status and related pathological conditions. An overview of the intracrine regulation in extra gynecological tissues such as the lungs, gastrointestinal tract, brain, colon and bone is given. Current therapeutic approaches aimed at interfering with these metabolisms and future perspectives are discussed.

Prevalence and predictors of small intestinal bacterial overgrowth in irritable bowel syndrome: a systematic review and meta-analysis

BACKGROUND

The reported prevalence of small intestinal bacterial overgrowth (SIBO) among individuals with irritable bowel syndrome (IBS) is highly variable. The aim of the study is to estimate the prevalence and identify predictors of SIBO in IBS.

METHODS

PubMed, Cochrane Library, and EMBASE through July 2017 were searched to identify studies evaluating the prevalence of SIBO in IBS. The pooled prevalence of SIBO among individuals with IBS and the pooled odds ratio (OR) of SIBO among those with IBS compared with healthy controls were calculated. Predictors of SIBO among IBS patients were also evaluated.

RESULTS

Fifty studies (8398 IBS, 1432 controls) met the inclusion criteria. Overall pooled prevalence of SIBO in IBS was 38% (95% CI 32-44) and was higher among individuals with IBS (OR 4.7, 95% CI 3.1-7.2) compared with controls. The pooled prevalence of SIBO in IBS was higher in studies diagnosed by breath tests (40%, 95% CI 33-46) compared with cultures (19%, 95% CI 8-30). Among those with IBS, female gender (OR 1.5, 95% CI 1.0-2.1), older age (standard mean difference 3.1 years, 95% CI 0.9-5.4), and IBS-diarrhea (OR 1.7, 95% CI 1.3-2.3) compared with other IBS subtypes increased the odds of SIBO; proton pump inhibitor (PPI) use (OR 1.1, 95% CI 0.7-1.7) was not associated with SIBO.

CONCLUSIONS

More than one-third of IBS patients tested positive for SIBO, and the odds of SIBO in IBS were increased by nearly fivefold. The prevalence of SIBO varied according to the diagnostic modality performed. Female gender, older age, and IBS-diarrhea, but not PPI use, were associated with SIBO among individuals with IBS.

Effects of Estrogen on the Gastrointestinal Tract

Estrogen is a kind of steroid compound that has extensive biologic activities. The effect of estrogen is pleiotropic, affecting multiple systems in the body. There is accumulating evidence that estrogen has important effects on the gastrointestinal tract. Longer exposure to estrogen may decrease the risk of gastric cancer. Use of the anti-estrogen drug tamoxifen might increase the risk of gastric adenocarcinoma. Estrogen receptor β may serve as a target for colorectal cancer prevention. In addition, estrogen has been reported to be closely related to the mucosal barrier, gastrointestinal function and intestinal inflammation. However, the role of estrogen in the gastrointestinal tract has not been systematically summarized. In this review, we aim to provide an overview of the role of estrogen in the gastrointestinal tract and evaluate it from various aspects, including estrogen receptors, the mucosal barrier, intestinal inflammation and gastrointestinal tract tumors, which may provide the basis for the development of therapeutic strategies to manage gastrointestinal diseases.

THE PROTECTIVE ROLE OF ESTRADIOL & PROGESTERONE IN MALE RATS, FOLLOWING GASTRIC ISCHEMIA-REPERFUSION

Background and Aim

Ischemia-reperfusion (I/R) injury frequently occurs in different situations. Female sex hormones have a protective function. The purpose of this study was to determine the function of female sexual hormones on the gastric damage induced by I/R in male rats.

Methods

Forty (40) Wistar rats were randomized into five groups: intact, ischemia- reperfusion (IR), IR + estradiol (1mg/kg), IR + progesterone (16 mg / kg) and IR + combination of estradiol (1mg / kg) and progesterone (16 mg/ kg). Before the onset of ischemia and before reperfusion all treatments were done by intraperitoneal (IP) injection. After animal anesthesia and laparotomy, celiac artery was occluded for 30 minutes and then circulation was established for 24 hours. Results expressed as mean ± SEM and P <0.05 were considered statistically significant.

Results

The Glutathione (GSH) concentration significantly decreased after induction of gastric IR (P<0.001). Estradiol (P<0.001) and combined estradiol and progesterone (P<0.001) significantly increased GSH levels. The myeloperoxidase (MPO) concentration significantly increased after induction of gastric IR (P<0.001). Different treatments significantly reduced MPO levels (P<0.001). The gastric acid concentration significantly increased after induction of gastric IR (P<0.001). Treatment with estradiol, progesterone (P<0.05) and combined estradiol and progesterone (P<0.01) significantly reduced gastric acid levels. Superoxide dismutase (SOD) concentration decreased after induction of gastric IR. The SOD levels were not significant.

Conclusion

These data suggested that female sexual steroids have a therapeutic effect on gastrointestinal ischemic disorders by reduction of MPO and gastric acid, and increasing gastric GSH & SOD levels following gastric IR.

Oestrogen upregulates the expression levels and functional activities of duodenal mucosal CFTR and SLC26A6

NEW FINDINGS

What is the central question of this study? Duodenal ulcer is a common disease. A sex-based difference in the incidence of duodenal ulcer has long been observed clinically, but the cause is unclear. What is the main finding and its importance? Duodenal mucosal bicarbonate secretion is the most important protective factor in duodenal mucosa against acid-induced damage. The cystic fibrosis transmembrane conductance regulator (CFTR) and the solute-linked carrier 26 gene family A6 (SLC26A6) are two key bicarbonate transport proteins that mediate duodenal mucosal bicarbonate secretion. We demonstrate that endogenous oestrogen upregulates the expression levels and functional activities of duodenal mucosal CFTR and SLC26A6, which contributes to the sex difference in the prevalence of duodenal ulcer. The incidence of duodenal ulcer is markedly lower in women than men, but the cause of the sex difference is not clear. The cystic fibrosis transmembrane conductance regulator (CFTR) and the solute-linked carrier 26 gene family A6 (SLC26A6) are two key bicarbonate transport proteins that mediate duodenal mucosal bicarbonate secretion, which is an important protective factor against acid-induced duodenal injury. The aim of this study was to investigate the effect of oestrogen on the expressions and functional activities of CFTR and SLC26A6 in duodenal mucosa. We found that the expression levels of duodenal CFTR and SLC26A6 were markedly higher in young (20- to 30-year-old) women than in young men and old (60- to 70-year-old) women and men. The expression levels of CFTR and SLC26A6 in young women were markedly higher in preovulatory phases than in premenstrual phases, which was consistent with the changes of serum estradiol concentrations. Further results showed that duodenal CFTR and SLC26A6 expression levels in female mice were markedly decreased after ovariectomy, and supplementation with estradiol reversed the changes in CFTR and SLC26A6. 17β-Estradiol increased CFTR and SLC26A6 expression levels of human duodenocytes in experiments in vitro. Functional experiments showed that basal and forskolin- and prostaglandin E₂ -stimulated duodenal bicarbonate secretion in ovariectomized mice was markedly decreased and, likewise, supplementation with 17β-estradiol reversed the changes. In conclusion, endogenous oestrogen upregulates the expressions and functional activities of CFTR and SLC26A6 in duodenal mucosa, which could contribute to protection of the duodenum and explain the sex difference in the prevalence of duodenal ulcer.

Estrogen and estrogen receptors in the modulation of gastrointestinal epithelial secretion

Gastrointestinal (GI) epithelial ion transport is physiologically important in many aspects of humans, such as in maintaining fluid balance of whole body, and also plays a role in the development and progression of common GI disease. Estrogen and estrogen receptors have been shown to modulate the activity of epithelial ion secretion in GI tract. This review aims to address the current state of knowledge about the role of estrogen and estrogen receptors in modulation of GI epithelial secretion and to elucidate the underlying mechanisms. We highlight the recent findings regarding the importance of estrogen and estrogen receptors in GI epithelia protection and body fluid balance by modulation of gastrointestinal epithelial HCO₃^- and Cl^- secretion, especially current information about the regulatory mechanisms of duodenal HCO₃^- secretion based on our study in this field. Since there are no reviews on this topic but only few papers to address the main issues, we hope to timely provide new perspectives for the association between estrogen and GI disease.

Sex differences and effects of oestrogen in rat gastric mucosal defence

AIM

To evaluate sex differences and the effects of oestrogen administration in rat gastric mucosal defence.

METHODS

Sex differences in gastric mucus thickness and accumulation rate, absolute gastric mucosal blood flow using microspheres, the integrity of the gastric mucosal epithelium in response to a chemical irritant and the effects of oestrogen administration on relative gastric mucosal blood flow in an acute setting was assessed in an in vivo rat experimental model. Subsequently, sex differences in the distribution of oestrogen receptors and calcitonin gene related peptide in the gastric mucosa of animals exposed to oestrogen in the above experiments was evaluated using immunohistochemistry.

RESULTS

The absolute blood flow in the GI-tract was generally higher in males, but only significantly different in the corpus part of the stomach (1.12 ± 0.12 mL/min•g in males and 0.51 ± 0.03 mL/min•g in females) (P = 0.002). After removal of the loosely adherent mucus layer the thickness of the firmly adherent mucus layer in males and females was 79 ± 1 µm and 80 ± 3 µm respectively. After 60 min the mucus thickness increased to 113 ± 3 µm in males and 121 ± 3 µm in females with no statistically significant difference seen between the sexes. Following oestrogen administration (0.1 followed by 1 µg/kg•min), mean blood flow in the gastric mucosa decreased by 31% [68 ± 13 perfusion units (PFU)] in males which was significantly different compared to baseline (P = 0.02). In females however, mean blood flow remained largely unchanged with a 4% (5 ± 33 PFU) reduction. The permeability of the gastric mucosa increased to a higher level in females than in males (P = 0.01) after taurocholate challenge. However, the calculated mean clearance increase did not significantly differ between the sexes [0.1 ± 0.04 to 1.1 ± 0.1 mL/min•100 g in males and 0.4 ± 0.3 to 2.1 ± 0.3 mL/min•100 g in females (P = 0.065)]. There were no significant differences between 17β-Estradiol treated males (mean ratio of positive staining ± SEM) (0.06 ± 0.07) and females (0.11 ± 0.11) in the staining of ERα (P = 0.24). Also, there were no significant differences between 17β-Estradiol treated males (0.18 ± 0.21) and females (0.06 ± 0.12) in the staining of ERβ (P = 0.11). Finally, there were no significant differences between 17β-Estradiol treated males (0.04 ± 0.05) and females (0.11 ± 0.10) in the staining of CGRP (P = 0.14).

CONCLUSION

Gastric mucosal blood flow is higher in male than in female rats and is reduced in male rats by oestrogen administration.

Association of Dementia and Peptic Ulcer Disease: A Nationwide Population-Based Study

OBJECTIVE

We determine the association between dementia and the subsequent peptic ulcer disease (PUD).

METHODS

We identified patients with diagnosed dementia in the Taiwan National Health Insurance Research Database. A comparison cohort without dementia was frequency-matched by age, sex, and comorbidities, and the occurrence of PUD was evaluated in both cohorts.

RESULTS

The dementia and control cohort consisted of 6014 patients with dementia and 17 830 frequency-matched patients without dementia, respectively. The incidence of PUD (hazard ratio, 1.27; 95% confidence interval, 1.18-1.37; P < .001) was higher among patients with dementia. Cox models showed that being female, diabetes mellitus, chronic kidney disease, coronary artery disease, and chronic obstructive pulmonary disease were independent risk factors for PUD in patients with dementia.

CONCLUSION

Dementia might increase the risk of developing PUD.

Lactulose Hydrogen Breath Test Result Is Associated with Age and Gender

Small intestinal bacterial overgrowth (SIBO) is associated with chronic gastrointestinal diseases and structural/functional abnormalities of the gastrointestinal tract. SIBO's association with clinical characteristics is unclear. This study investigates the association between clinical factors and SIBO according to lactulose hydrogen breath test (LHBT) result. Methods. A cross-sectional study in a university-based gastroenterology practice was performed. Data was abstracted from the medical records of subjects undergoing LHBT from 6/1/2009 to 6/1/2013. Logistic regression analysis was performed to determine the association between predictor variables: age, sex, body mass index (BMI), and positive LHBT, the outcome of interest. Results. LHBT was performed in 791 subjects. Fifty-four percent had a positive LHBT. There was no statistically significant difference between the LHBT results according to age or BMI. In females, the likelihood of a positive LHBT increased with age (OR 1.02; 95% CI: 1.01–1.03). In males, the likelihood of a positive LHBT result decreased with age (OR 0.98; 95% CI: 0.97–1.00). Conclusion. There was an association between age, with respect to sex, and a positive LHBT. With increased age in females, the odds of a positive LHBT increased, while, in men, the odds of a positive LHBT decreased with age.

Ontogenetic changes in the expression of estrogen receptor β in mouse duodenal epithelium

Estrogen is considered to be involved in duodenal function; however, the details of its receptor expression are largely unknown. The purpose of this study was to determine the expression and localization of estrogen receptors (ERs) in mouse duodenum. Male and female C57BL/6J mouse intestinal tissues were used to investigate the expression of ERα and ERβ by RT-PCR, western blotting, immunohistochemistry, and Southwestern histochemistry. ERβ, but not ERα, was expressed in proximal duodenal epithelium, but not in jejunum and ileum. The expression of ERβ mRNA and protein were confirmed by RT-PCR and western blotting, respectively. At postnatal day 20, the transit period of suckling to weaning, the distribution of ERβ-positive cells was changed in the crypt-villus axis, and cytoplasm/nuclear staining changed to only nuclear staining. Moreover, Southwestern histochemistry was used to detect estrogen response element (ERE)-binding proteins, and their expression pattern was highly similar to that of ERβ. These results suggested that ERβ is the predominant ER type in mouse small intestine, and the highly similar co-localization of ERE-binding proteins reveals that ERβ is functionally active in mouse duodenum. The ERβ expression changes during postnatal development indicate that ERβ may be involved in the differentiation of duodenal epithelium.

Estrogen alleviates acetic acid-induced gastric or colonic damage via both ERα- and ERβ-mediated and direct antioxidant mechanisms in rats

In order to demonstrate the possible protective effects of estrogen receptor (ER)-α and ERβ receptor subtypes in the pathogenesis of colonic and gastric oxidant damage, experimental ulcer and colitis were induced by acetic acid, and the animals were randomly divided as colitis, ulcer, and their corresponding non-ulcer and non-colitis control groups. Each group of rats was treated intramuscularly with the vehicle, selective ERα agonist propylpyrazole-triol (1 mg/kg), ERβ agonist diarylpropionitrile (1 mg/kg), non-selective ER agonist 17β estradiol (E2; 1 mg/kg), or E2 plus non-selective ER antagonist ICI-182780 (1 mg/kg). The results revealed that induction of ulcer or colitis resulted in systemic inflammation as assessed by increased levels of plasma TNF-α and IL-6 levels. In both tissues, the presence of oxidant damage was verified by histological analysis and elevated myleoperoxidase activity. In the colitis and ulcer groups, both ER agonists and the non-selective E2 reversed the oxidative damage in a similar manner. These findings indicate that estrogen acts via both ERα- and ERβ-mediated and direct antioxidant mechanisms, where both ER subtypes play equal and efficient roles in the anti-inflammatory action of estrogen, in limiting the migration of neutrophils to the inflamed tissue, reducing the release and activation of cytokines and thereby alleviating tissue damage.

The effects of female sexual steroids on gastric function and barrier resistance of gastrointestinal tract following traumatic brain injury

AIM

The aim was to assess the alteration of gastric function and barrier function of gastrointestinal (GI) tract following diffuse brain injury in varying ovarian hormone status.

MATERIALS AND METHODS

Diffuse traumatic brain injury (TBI) was induced by Marmarou method. Rats were randomly assigned into 10 groups: Intact, sham + ovariectomized female (OVX), TBI, TBI + OVX, vehicle, estradiol (E2), progesterone (P), E2 + P, estrogen receptor alpha agonist and estrogen receptor beta agonist (DPN). Endotoxin levels were measured using enzyme-linked immunosorbent assay method. All the parameters were measured 5 days after TBI.

RESULTS

Intragastric pressure was significantly decreased in TBI as compared to the intact group (P < 0.001) and this was lower in TBI group versus TBI + OVX group (P < 0.05). Pretreatment with steroid hormones and their agonists did not have any effect on the gastric pressure compared to TBI + OVX or vehicle groups. Inflammation, congestion, ulcer and erosion were seen in the TBI rats. All treatment groups worsen the tissue condition so that the presence of thrombosis also was seen. The trauma induction did not have any effect on the serum and intestinal endotoxin levels. DPN had caused a significant reduction in serum levels of endotoxin compared with OVX + TBI group (P < 0.05).

CONCLUSION

Pretreatment with sexual steroids is not useful in the treatment of GI dysfunction induced by TBI. The treatment with all sexual female hormones worsens the gastric tissue condition. Furthermore, the applied weight was not enough for releasing of endotoxin. It seems that estrogen reduced the endotoxin levels by estrogen beta receptor.

Molecular mechanisms of calcium-sensing receptor-mediated calcium signaling in the modulation of epithelial ion transport and bicarbonate secretion

Epithelial ion transport is mainly under the control of intracellular cAMP and Ca(2+) signaling. Although the molecular mechanisms of cAMP-induced epithelial ion secretion are well defined, those induced by Ca(2+) signaling remain poorly understood. Because calcium-sensing receptor (CaSR) activation results in an increase in cytosolic Ca(2+) ([Ca(2+)]cyt) but a decrease in cAMP levels, it is a suitable receptor for elucidating the mechanisms of [Ca(2+)]cyt-mediated epithelial ion transport and duodenal bicarbonate secretion (DBS). CaSR proteins have been detected in mouse duodenal mucosae and human intestinal epithelial cells. Spermine and Gd(3+), two CaSR activators, markedly stimulated DBS without altering duodenal short circuit currents in wild-type mice but did not affect DBS and duodenal short circuit currents in cystic fibrosis transmembrane conductance regulator (CFTR) knockout mice. Clotrimazole, a selective blocker of intermediate conductance Ca(2+)-activated K(+) channels but not chromanol 293B, a selective blocker of cAMP-activated K(+) channels (KCNQ1), significantly inhibited CaSR activator-induced DBS, which was similar in wild-type and KCNQ1 knockout mice. HCO3 (-) fluxes across epithelial cells were activated by a CFTR activator, but blocked by a CFTR inhibitor. CaSR activators induced HCO3 (-) fluxes, which were inhibited by a receptor-operated channel (ROC) blocker. Moreover, CaSR activators dose-dependently raised cellular [Ca(2+)]cyt, which was abolished in Ca(2+)-free solutions and inhibited markedly by selective CaSR antagonist calhex 231, and ROC blocker in both animal and human intestinal epithelial cells. Taken together, CaSR activation triggers Ca(2+)-dependent DBS, likely through the ROC, intermediate conductance Ca(2+)-activated K(+) channels, and CFTR channels. This study not only reveals that [Ca(2+)]cyt signaling is critical to modulate DBS but also provides novel insights into the molecular mechanisms of CaSR-mediated Ca(2+)-induced DBS.

Helicobacter pylori Infection in European children with gastro-duodenal ulcers and erosions

BACKGROUND

To analyze risk factors associated with gastro-duodenal ulcers and erosions in children.

METHODS

Open, prospective, multicenter, case-control study carried out in 11 European countries in patients with gastric or duodenal ulcers/erosions and 2 age-matched controls each. Possible risk factors were recorded. Logistic regression models were performed with adjustment for centers and age groups.

RESULTS

Seven-hundred thirty-two patients (244 cases, 153 with erosions only and 91 with ulcers, and 488 controls) were recruited. Children receiving antimicrobials or acid suppressive drugs before endoscopy were excluded (202 cases/390 controls remained for risk factor analysis). Helicobacter pylori was detected more frequently in cases than controls but only in 32.0% versus 20.1% in controls (P = 0.001). Independent exposure factors for gastric ulcers were male gender (P = 0.001), chronic neurologic disease (P = 0.015), chronic renal disease (P < 0.001) and nonsteroidal anti-inflammatory drug consumption (P = 0.035). Exposure factors for duodenal ulcers were H. pylori infection (P < 0.001) and steroid consumption (P = 0.031). Chronic renal disease was the only independent factor associated with gastric erosions (P = 0.026), those associated with duodenal erosions being H. pylori infection (P = 0.023), active smoking (P = 0.006) and chronic arthritis (P = 0.008). No risk factor was identified in 97/202 (48.0%) cases.

CONCLUSIONS

H. pylori remains a risk factor for duodenal, but not for gastric lesions in children in countries with low prevalence of infection. No risk factor could be identified in half of the children with gastro-duodenal ulcers/erosions.

Higher serum levels of rheumatoid factor and anti-nuclear antibodies in helicobacter pylori-infected peptic ulcer patients

OBJECTIVES

H. pylori infection has been associated with some autoimmune disorders. The aim of this study was to evaluate the serum concentrations of rheumatoid factor and anti-nuclear antibodies in H. pylori-infected peptic ulcer patients, H. pylori-infected asymptomatic carriers and a healthy control group.

METHODS

A Total of 100 H. pylori-infected peptic ulcer patients, 65 asymptomatic carriers and 30 healthy H. pylori-negative subjects (as a control group) were enrolled into study. Serum samples of participants tested for the levels of rheumatoid factor and anti-nuclear antibodies by use of ELISA.

RESULTS

The mean serum levels of rheumatoid factor and anti-nuclear antibodies in peptic ulcer group was significantly higher in comparison to the control group (p<0.05). Although, the mean serum levels of rheumatoid factor and anti-nuclear antibodies in the asymptomatic carriers group was higher than those in the control group, the difference was not statistically significant. No significant differences were observed between peptic ulcer patients and asymptomatic carriers groups regarding the mean serum levels of rheumatoid factor and anti-nuclear antibodies. The mean serum levels of rheumatoid factor in men with peptic ulcer was significantly higher compared to the group of healthy men (p<0.05). Although in female of peptic ulcer patients or asymptomatic carriers groups, the mean serum levels of rheumatoid factor was higher than that in healthy women, but the differences were not statistically significant. Also, no significant differences were observed between men and women with peptic ulcer, asymptomatic carriers control groups based on the serum levels of anti-nuclear antibodies.

CONCLUSION

The results showed higher serum levels of rheumatoid factor and anti-nuclear antibodies in H. pylori-infected patients with peptic ulcer disease which represent the H. pylori-related immune disturbance in these patients. Additional follow-up studies are necessary to clarify the clinical significance of these autoantibodies in patients with H. pylori infection.

The effect of female sexual hormones on the intestinal and serum cytokine response after traumatic brain injury: different roles for estrogen receptor subtypes

The purpose of this study was to evaluate the effect of female sexual hormones on intestinal and serum cytokines following traumatic brain injury (TBI). Adult female rats were ovariectomized and distributed among the following 9 groups: (i) sham trauma, (ii) TBI (Marmarou's method), (iii) vehicle (dimethylsulfoxide) treated, (iv) estrogen (E2) treated, (v) progesterone (P) treated, (vi) treated with E2+P, (vii) propylpyrazole triol (PPT) treated, (viii) diarylpropionitrile (DPN) treated, and (ix) control. PPT and DPN are estrogen receptor αand β agonists, respectively. Serum and intestinal levels of interleukin (IL)-1β were increased by TBI (P < 0.001). The level of intestinal IL-1β was increased in the group treated with E2 (P < 0.001). There was a reduction in serum IL-1β (P < 0.01) and an increase in intestinal IL-1β level (P < 0.001) in the PPT-treated group compared with the vehicle-treated group. TBI reduced serum IL-6 (P < 0.01) and increased intestinal IL-6 (P < 0.001). Serum IL-6 was increased in the group treated with E2 (P < 0.001), P (P < 0.001), E2+P (P < 0.01), and DPN (P < 0.001) after TBI; however, intestinal IL-6 was higher in the E2-treated group compared with the vehicle-treated group (P < 0.01). Intestinal tumor necrosis factor α (TNF-α) was increased by TBI (P < 0.001). Progesterone decreased serum TNF-α (P < 0.01). Intestinal TNF-α in the E2 (P < 0.01), E2+P (P < 0.001), and PPT (P < 0.001) treatment groups was less than in the vehicle-treated group. In conclusion, estrogen influences the intestinal levels of proinflammatory cytokines, in particular TNF-α, mediated through estrogen receptor α.

In-vivo functional study on the involvement of CFTR, SLC26A6, NHE-1 and CA isoenzymes II and XII in uterine fluid pH, volume and electrolyte regulation in rats under different sex-steroid influence

Precise control of uterine fluid pH, volume and electrolytes is important for the reproductive processes. In this study, we examined the functional involvement of multiple proteins including Cystic Fibrosis Transmembrane Regulator (CFTR), Cl(-)/HCO3 (-) exchanger (SLC26A6), sodium-hydrogen exchanger-1 (NHE-1) and carbonic anhydrase (CA) in the regulation of these uterine fluid parameters.

METHODS

Adult female WKY rats were divided into intact, non-ovariectomised at different oestrous cycle phases and ovariectomised treated with sex-steroids. Following oestrous phase identification or sex-steroid treatment, in-vivo uterine perfusion was performed with and without the presence of these inhibitors: glibenclamide, DIDS, ACTZ and EIPA. The pH, volume, Cl(-), HCO3 (-) and Na(+) concentrations of the perfusate from different groups were then analyzed. Meanwhile, the expression of CFTR, SLC26A6, NHE-1, CAII and CAXII was visualized by immunohistochemistry (IHC).

RESULTS

Parallel increase in the pH, volume, Cl(-), HCO3 (-) and Na(+) concentrations was observed at estrus (Es), proestrus (Ps) and following 17β-oestradiol (E) treatment, which was inhibited by glibenclamide, DIDS and ACTZ while parallel reduction in these parameters was observed at diestrus (Ds) and following progesterone (P) treatment which was inhibited by ACTZ and EIPA. CFTR and SLC26A6 expression were up-regulated under E dominance, while NHE-1 expression was up-regulated under P dominance. Meanwhile, CA isoenzymes were expressed under both E and P influence.

CONCLUSION

CFTR, SLC26A6 and CA were involved in mediating parallel increase in the uterine fluid volume, pH and electrolyte concentration under E while NHE and CA were involved in mediating the reduction of these parameters under P.

Progesterone downregulates oestrogen-induced expression of CFTR and SLC26A6 proteins and mRNA in rats' uteri

Under progesterone (P) dominance, fluid loss assists uterine closure which is associated with pH reduction. We hypothesize that P inhibits uterine fluid secretion and HCO3⁻ transport. Aim. to investigate the expression of Cystic Fibrosis Transmembrane Regulator (CFTR) and Cl⁻/HCO3⁻ exchanger (SLC26A6) under P effect. Method. Uteri from ovariectomized steroid replaced and intact rats at different stages of oestrous cycle were analyzed for changes in protein and mRNA expressions. Results. P inhibits CFTR and SLC26A6 proteins and mRNA expression while oestrogen (E) causes vice versa. E treatment followed by P causes a reduction in these transporters' mRNA and protein. Similar changes occur throughout the oestrous cycle; that is, CFTR mRNA expression was high at proestrus while SLC26A6 mRNA and protein expressions were increased at proestrus and estrus. At diestrus, however, the expression of these transporters' protein and mRNA was reduced. Conclusion. Inhibition of CFTR and SLC26A6 expressions may explain the reduced fluid volume and pH under P-mediated effect.

[Epidemiological differences in upper gastrointestinal bleeding between men and women]

Introduction

Des différences épidémiologiques, étiologique voire pronostique des hémorragies digestives hautes (HDH) entre les deux sexes opposés ont été cité par différentes études.

Méthodes

Nous avons essayé de déceler ces différences à travers une analyse rétrospective nichée sur une étude prospective sur les hémorragies digestives hautes ayant inclus 945 patients.

Résultats

Six cents trente-sept patients étaient des hommes (67,4% Vs 32,6%). Un antécédent d'HDH était trouvé chez 24,2% des cas sans différence significative entre les deux sexes. L'âge de survenue de l'hémorragie était plus élevé chez les femmes que chez les hommes : 51,5 ans ± 18,8 Vs 47,8 ans ± 18,3 (p : 0,003). Les étiologies de l'HDH étaient différentes entre les deux sexes. Alors que l'hémorragie liée à l'HTP était la première cause chez la femme (38 % Vs 23,5 % chez l'homme, p<0,0001), c'est la pathologie ulcéreuse qui venait en premier chez l'homme (62 % Vs 36,7 % chez la femme, p<0,0001). Un besoin transfusionnel était noté chez 42,4 % des patients de sexe masculin contre 35,4 % des patientes avec un p = 0,03. Le taux de récidive et de décès global étaient de 7,5 % et de 5,7 % des cas respectivement, sans différence significative entre les deux sexes.

Conclusion

L'étude trouve un profil épidémiologique, clinique et étiologique différent selon le sexe des patients.

Estrogen potentiates prostaglandin E₂-stimulated duodenal mucosal HCO₃⁻ secretion in mice

The cause of lower prevalence of duodenal ulcer in young women compared with men is largely unknown. We recently found that sex difference in duodenal mucosal HCO₃⁻ secretion existed in humans and mice, but the mechanisms are not clear. Prostaglandin E₂ (PGE₂) is an important endogenous mediator that plays an important role in the regulation of duodenal HCO₃⁻ secretion. Therefore, in the present study, we investigated the effect of estrogen on PGE₂-stimulated duodenal HCO₃⁻ secretion and the underlying mechanisms. The results showed that 17β-estradiol at the physiological concentration (1 nM) had no significant effects on duodenal mucosal HCO₃⁻ secretion or short-circuit current (I(sc)) in mice. However, the pretreatment of 17β-estradiol (1 nM) markedly potentiated PGE₂-stimulated duodenal HCO₃⁻ secretion and I(sc) (P < 0.01 and P < 0.05). Global estrogen receptor (ER) antagonist ICI-182,780 and ERα-specific antagonist MPP, but not the ERβ-specific antagonist PHTPP, abolished estrogen-potentiated PGE₂-stimulated duodenal HCO₃⁻ secretion and I(sc). 17β-Estradiol and PGE₂ additively increased phosphatidylinositol 3-kinase (PI3K) activity and Akt phosphorylation. Wortmannin, a specific PI3K inhibitor, inhibited estrogen-potentiated PGE₂-stimulated duodenal HCO₃⁻ secretion and I(sc). In conclusion, estrogen at the physiological concentration potentiates PGE₂-stimulated duodenal mucosal HCO₃⁻ secretion through the activation of ERα and the PI3K-dependent mechanism, which may contribute to the sex difference in duodenal mucosal HCO₃⁻ secretion and the lower prevalence of duodenal ulcer in young women.

Estrogen regulation of duodenal bicarbonate secretion and sex-specific protection of human duodenum

BACKGROUND & AIMS

The reason that women have a lower prevalence of duodenal ulcer is not clear. We investigated whether estrogen regulates human duodenal bicarbonate secretion (DBS) and whether this process accounts for sex differences in the prevalence of duodenal ulcer.

METHODS

We performed an epidemiologic study to correlate duodenal ulcer prevalence with sex and age. Proximal DBS was measured from healthy subjects. Estrogen-receptor expression was examined in human duodenal mucosa by immunoblot and immunohistochemical analyses.

RESULTS

Among women, the prevalence of duodenal ulcer was significantly lower than among men. The reduced prevalence was greatest among premenopausal women (20-49 y), who were 3.91- to 5.09-fold less likely to develop duodenal ulcers than age-matched men; the difference was reduced to 1.32-fold or less among subjects aged 60 years or older. Premenopausal (20-29 y), but not postmenopausal (60-69 y), women had significantly higher basal and acid-stimulated DBS than the age-matched men. Basal and acid-stimulated DBS in premenopausal women (20-29 y) were significantly higher than in postmenopausal women (60-69 y), whereas there were no significant differences in basal or acid-stimulated DBS between men who were aged 20-29 years or 60-69 years. Serum levels of estradiol changed in parallel with basal and acid-stimulated DBS during the physiological menstrual cycle in premenopausal women. 17β-estradiol-stimulated DBS was independent of age or sex. Estrogen receptors α and β were detected on plasma membranes and in the cytosol of human duodenal epithelial cells.

CONCLUSIONS

Estrogen regulates human DBS, which could reduce the risk for duodenal ulcer in women and contribute to sex differences in the prevalence of duodenal ulcer.

Expression of acid-sensing ion channels in intestinal epithelial cells and their role in the regulation of duodenal mucosal bicarbonate secretion

AIMS

As little is currently known about acid-sensing ion channels (ASICs) in intestinal epithelial cells, the aims of the present study were to investigate the expression and function of ASICs in intestinal epithelial cells, particularly their physiological role in the acid-stimulated duodenal mucosal bicarbonate secretion (DMBS).

METHODS

RT-PCR and digital Ca²(+) imaging were used to determine the expression and function of ASICs in HT29 cells and SCBN cells, intestinal epithelial crypt cell lines. The acid-stimulated DMBS was measured in C57 black mice in vivo to study the role of ASICs in this physiological process.

RESULTS

ASIC1a mRNA expression was detected in the duodenal mucosa stripped from mice and epithelial cell lines, in which cytoplasmic free Ca²(+) ([Ca²(+) ](cyt)) in response to extracellular acidosis was also increased. In Ca²(+) -containing solutions, acidosis (pH 6.0-5.0) raised [Ca²(+) ](cyt) in both HT29 cells and SCBN cells in a similar pH-dependent manner. Acidosis-induced increase in [Ca²(+) ](cyt) was markedly inhibited by amiloride (an ASICs blocker), SK&F96365 (a blocker for non-selective cation channels), or in Ca²(+) -free solutions; but was abolished by amiloride in Ca²(+) -free solutions. However, acidosis-induced increase in [Ca²(+) ](cyt) was slightly affected by U73122 (a PLC inhibitor), or nifedipine (a voltage-gated Ca²(+) channel blocker). After acidosis raised [Ca²(+) ](cyt) , stimulation of purinergic receptors with ATP further increased [Ca²(+) ](cyt) , but acidosis-induced increase in [Ca²(+) ](cyt) was not altered by suramin. Moreover, acid-stimulated murine DMBS was significantly attenuated by amiloride.

CONCLUSION

Therefore, ASICs are functionally expressed in intestinal epithelial cells, and may play a role in acid-stimulated DMBS through a Ca²(+) signalling pathway.

Genistein stimulates duodenal HCO(3)(-) secretion through PI3K pathway in mice

Genistein has been proposed as a promising pharmacotherapeutic for cystic fibrosis. We recently found that genistein stimulates murine duodenal HCO(3)(-) secretion through cystic fibrosis transmembrane conductance regulator (CFTR). The aim of the present study was to determine the intracellular signal pathways involved in genistein-stimulated duodenal HCO(3)(-) secretion. Murine duodenal mucosal HCO(3)(-) secretion was examined in vitro in Ussing chambers by the pH-stat technique. The results showed that neither cAMP-dependent signal pathway inhibitors MDL-12330A and KT-5720, nor cGMP signal pathway inhibitors NS2028 and KT5823, nor calcium signal pathway inhibitors verapamil and W-13, altered genistein-stimulated duodenal HCO(3)(-) secretion. In calcium-free solution, genistein-stimulated duodenal HCO(3)(-) secretion was not altered either. Vanadate, an inhibitor of protein tyrosine phosphatase, only partially inhibited genistein-stimulated duodenal HCO(3)(-) secretion. However, both wortmannin and LY294002, two structurally and mechanistically distinct phosphatidylinositol 3-kinase (PI3K) inhibitors, markedly inhibited genistein-stimulated duodenal HCO(3)(-) secretion. Genistein increased duodenal mucosal PI3K activity and induced the phosphorylation of Akt, a signaling molecule downstream of PI3K, which was again inhibited by wortmannin. Estrogen receptor antagonist, ICI182,780, also markedly inhibited genistein-stimulated duodenal HCO(3)(-) secretion and genistein-induced PI3K activity increase in duodenal mucosa. These results demonstrate that genistein stimulates duodenal HCO(3)(-) secretion mainly through estrogen receptor and PI3K-dependent pathway. These findings contribute to the understanding of the molecular mechanism of genistein-induced anion secretion and further pharmacotherapeutic development and use of genistein or related substances in the treatment of diseases of epithelial tissues.

Poor endoscopic findings in children with non variceal upper gastrointestinal bleeding: is biopsy necessary?

BACKGROUND

Gastrointestinal bleeding in infants and children is a potentially serious condition in the practice of general pediatrics that requires investigation. The objective of this study is to describe the endoscopic and histopathological findings in children with upper gastrointestinal (UGI) bleeding of non variceal origin.

PATIENTS AND METHODS

We performed a retrospective study of the medical records of 181 children, aged 1 month to 15.2 years, with non variceal UGI bleeding, who were admitted in our department over the period 1988-2008 and underwent upper GI endoscopy accompanied by histology. Patients were divided in 4 groups according to their age (=0-1 years, = 1-6 years, C=6-12 years, D= 12-16 years).

RESULTS

An endoscopically evident bleeding source was detected in only 5% of all patients. Histological examination revealed increased incidence of eosinophilic infiltration in infants, in contrast to all other age groups, where non-specific or H. pylori related inflammation predominated. Peptic ulcer was found in 4.4% of all patients.

CONCLUSION

Although an evident bleeding source was detected in only a small percentage of patients, the accompanying histological examination provided additional information regarding possible underlying diseases and contributed to the subsequent therapeutic management.

The protective effect of 17beta-estradiol postconditioning against hypoxia/reoxygenation injury in human gastric epithelial cells

The purpose of this study was to investigate the effects and mechanisms of 17beta-estradiol pharmacological postconditioning on gastric epithelial cells hypoxia/reoxygenation injury by using an in vitro model of human gastric epithelial cells. The model of hypoxia/reoxygenation was established with human gastric epithelial cell line. The gastric epithelial cell viability was detected by 3-(4, 5-dimethylthazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assays. Gastric epithelial cellular apoptosis was determined by Hoechst 33258 fluorochrome staining and flow cytometric analysis. Contents of malondialdehyde (MDA) and the activity of superoxide dismutase (SOD) were measured by Colorimetry analysis. The protein expression of Bcl-2 and Bax in different groups was determined by Western blot analyses and immunocytochemistry assay. 17beta-estradiol (10(-8), 10(-7) and 10(-6)mol/l) inhibited hypoxia/reoxygenation injury and 17beta-estradiol (10(-6)mol/l) obviously attenuated hypoxia/reoxygenation injury 3h hypoxia followed by 4h reoxygenation. 17beta-estradiol promoted gastric epithelial cell viability and inhibited the gastric epithelial cell apoptosis, and meanwhile, decreased the MDA content and increased SOD activity. The level of Bcl-2 protein was restored to the normal level by 17beta-estradiol pharmacological postconditioning. In contrast, the Bax protein level was markedly reduced by 17beta-estradiol pharmacological postconditioning. These effects of 17beta-estradiol were inhibited by pretreatment with fulvestrant. These data suggested that 17beta-estradiol seems involved in regulation of gastric hypoxia/reoxygenation injury and gastroprotection, and its protective effects were strongly related to estrogen receptor.

Correlation of heat shock protein expression to gender difference in development of stress-induced gastric mucosal injury in rats

Recent studies have indicated that heat shock proteins (HSPs), which function as molecular chaperones, play important roles in cellular responses to stress-related events. However, the gender difference in the expression of HSP in the gastric mucosa remains unclear. In order to understand the mechanism of gender difference in the prevalence or severity of gastric mucosal lesions, the expression level of HSP and the correlation of estrogen to HSP induction in the gastric mucosa were evaluated in this study. The basal expression levels of HSP60 and HSP90 in the gastric mucosa were significantly higher in females than those in males. The gastric ulcer index was significantly higher in male rats compared to female rats observed after 12 h water immersion stress exposure. At this time point, the expression levels of HSP60 and HSP90 in the gastric mucosa were significantly higher in females than those in males. An estrogen-treatment significantly induced the expression of HSP60, HSP70 and HSP90 in the gastric mucosa. Inversely, an ovariectomy dramatically reduced the expression of HSP60, HSP70 and HSP90 in the gastric mucosa. Our results suggested that estrogen might play an important role in gastric mucosal protection with the induction of gastric mucosal HSPs.

Cellular and molecular mechanisms of 17beta-estradiol postconditioning protection against gastric mucosal injury induced by ischemia/reperfusion in rats

AIMS

To investigate the protective effects of 17beta-estradiol postconditioning against ischemia/reperfusion (I-R)-induced gastric mucosal injury in rats.

MAIN METHODS

The animal model of gastric ischemia/reperfusion was established by clamping of the celiac artery for 30 min and reperfusion for 30 min, 1h, 3h, 6h, 12h or 24h. 17beta-estradiol at doses of 5, 50 or 100 microg/kg (rat) was administered via peripheral veins 2 min before reperfusion. In a subgroup of rats, the estrogen receptor antagonist fulvestrant (Ful, 2mg/kg) was intravenously injected prior to 17beta-estradiol administration. Histological and immunohistochemical methods were employed to assess the gastric mucosal injury index and gastric mucosal cell apoptosis and proliferation. The malondialdehyde (MDA) concentration, superoxide dismutase (SOD) activity, xanthine oxidase (XOD) activity and hydroxyl free radical (-OH) inhibitory ability were determined by colorimetric assays. Subsequently, the expression of Bcl-2 and Bax in rat gastric mucosa was examined by western blotting.

KEY FINDINGS

17beta-estradiol dose-dependently inhibited gastric I-R (GI-R) injury, and 17beta-estradiol (50 microg/kg) markedly attenuated GI-R injury 1h after reperfusion. 17beta-estradiol inhibited gastric mucosal cell apoptosis and promoted gastric mucosal cell proliferation in addition to increasing SOD activity and -OH inhibitory ability and decreasing the MDA content and XOD activity. The Bax protein level increased 1h after GI-R and was markedly reduced by intravenous administration of 17beta-estradiol. In contrast, the level of Bcl-2 protein decreased 1h after GI-R and was restored to normal levels by intravenous administration of 17beta-estradiol. These effects of 17beta-estradiol were inhibited by pretreatment with fulvestrant.

SIGNIFICANCE

17beta-estradiol postconditioning should be investigated further as a possible strategy against gastric mucosal injury.

Gastroduodenal mucosal defense

PURPOSE OF REVIEW

The gastroduodenum has multiple means by which it resists injury from intrinsic and extrinsic factors, including gastric acid, nonsteroidal anti-inflammatory drugs, and Helicobacter pylori. We review recent insights into the mechanisms by which the gastroduodenum resists injury and discuss factors contributing to defensive failure.

RECENT FINDINGS

Duodenal bicarbonate secretion, a primary defensive mechanism, is mediated by the downregulated in adenoma anion exchanger and is stimulated by estrogens. Nonsteroidal anti-inflammatory drug gastric damage is dependent on toll-like receptor signaling. Portal hypertensive gastropathy impairs extracellular signal-regulated kinase 1/2 phosphorylation, increasing oxidative stress. H. pylori-induced peptic ulcer disease is associated with inadequate regulatory T cell responses.

SUMMARY

Enhanced understanding of the mechanisms of gastroduodenal defense and injury provides new insight into potential therapeutic targets, which contributes towards the development of more well tolerated and more effective therapies.

Gastroduodenal mucosal defense

The gastroduodenal mucosa withstands injury from acid, drugs, foodstuffs, and other factors. Defense mechanisms include pre-epithelial and epithelial barriers, submucosal acid sensors, prostaglandin generation, endogenous protective gases, and other chemical mediators. Recent studies have focused on proteinase-activated receptors and their linkage to prostaglandin formation, as well as on antioxidants targeted to reduce harmful reactive oxygen species. Investigation continues into the protective roles of calcitonin gene-related peptide, hydrogen sulfide, annexin-1, survivin, and methylnicotinamide. This article also summarizes some new findings on the genetics of ulcer formation and the effects of age and gender on mucosal defense and touches on current developments in drugs, including considerations for future therapeutic agents.