Role of mucosal blood flow: a conceptional review in gastric mucosal injury and protection

Traditional Chinese medicine for chronic atrophic gastritis: Efficacy, mechanisms and targets

Chronic atrophic gastritis (CAG) is an important stage of precancerous lesions of gastric cancer. Effective treatment and regulation of CAG are essential to prevent its progression to malignancy. Traditional Chinese medicine (TCM) has shown multi-targeted efficacy in CAG treatment, with advantages in enhancing gastric mucosal barrier defense, improving microcirculation, modulating inflammatory and immune responses, and promoting lesion healing, etc. Clinical studies and meta-analyses indicate that TCM provides significant benefits, with specific Chinese herbal compounds and monomers demonstrating protective effects on the gastric mucosa through mechanisms including anti-inflammation, anti-oxidation, and regulation of cellular proliferation and apoptosis, etc. Finally, it is pointed out that the efficacy of TCM in the treatment of CAG requires standardized research and unified standards, and constantly clarifies and improves the evaluation criteria of each dimension of gastric mucosal barrier function.

Current study of pathogenetic mechanisms and therapeutics of chronic atrophic gastritis: a comprehensive review

Chronic atrophic gastritis (CAG) is a prevalent digestive system disease characterized by atrophy of the gastric mucosa and the disappearance of inherent gastric glands. According to the theory of Correa's cascade, CAG is an important pathological stage in the transformation from normal condition to gastric carcinoma. In recent years, the global incidence of CAG has been increasing due to pathogenic factors, including Helicobacter pylori infection, bile reflux, and the consumption of processed meats. In this review, we comprehensively described the etiology and clinical diagnosis of CAG. We focused on elucidating the regulatory mechanisms and promising therapeutic targets in CAG, with the expectation of providing insights and theoretical support for future research on CAG.

Targeting TRPV1 signaling: Galangin improves ethanol-induced gastric mucosal injury

ETHNOPHARMACOLOGICAL RELEVANCE

Galangin, a bioactive compound extracted from Alpinia officinarum Hance (Zingiberaceae), a plant with significant ethnopharmacological importance, has been used for thousands of years as a spice, condiment, and medicinal agent for various conditions, including gastrointestinal disorders. Although there is evidence suggesting its potential to improve gastric ulcers, the molecular mechanisms underlying its anti-ulcer properties are not fully understood.

OBJECTIVE

of the Study: This study aimed to investigate the effects of galangin on ethanol-induced acute gastric mucosal injury (AGMI) in mice and elucidate its molecular mechanisms.

MATERIALS AND METHODS

Sixty BALB/c mice were randomly assigned into two main groups: a normal control group (n = 10) and an ethanol-induced group (n = 50). After establishing the AGMI model in mice using a combination of 40% ethanol and anhydrous ethanol, the ethanol-induced group was further subdivided into five subgroups (n = 10): an omeprazole control group (20 mg/kg), an untreated ethanol group, and three treatment groups receiving high-dose (50 mg/kg) or low-dose (25 mg/kg) galangin or capsazepine (CPZ, 2 mg/kg). The protective effects of galangin were evaluated through mucosal injury indices, hematoxylin and eosin staining, and quantification of inflammatory markers (IL-1β, IL-6, IL-8, and TNF-α). Oxidative stress levels and matrix metalloproteinase activity were measured using specific assay kits. Molecular docking was conducted to assess the binding affinity of galangin to key proteins within the transient receptor potential vanilloid 1 (TRPV1) pathway. Real-time fluorescence quantitative PCR (qPCR) was used to determine mRNA expression levels of TRPV1, calmodulin (CaM), substance P (SP), and CGRP in gastric tissues. Protein expression levels of TRPV1, nerve growth factor (NGF), tropomyosin receptor kinase A (TRKA), transforming growth factor beta (TGF-β), cyclooxygenase-2 (COX-2), and nuclear factor kappa B (NF-κB) were assessed through Western blot analysis. In cellular experiments, Culture of Human Gastric Epithelial Cells (GES-1) were treated with various concentrations of galangin after 7% ethanol induction. Cell proliferation, apoptosis, and migration were evaluated using Hoechst 33258 staining and transwell migration assays. TRPV1 protein expression was detected using immunofluorescence, and the expression levels of Bcl-2, BCL2-Associated X (BAX), and Caspase-3 were quantified by qPCR. Additionally, specific probe kits were used to measure intracellular calcium ions (Ca2+) and mitochondrial membrane potential.

RESULTS

The findings indicate that galangin significantly improved mucosal pathology by reducing ulcer indices and inflammatory levels, while enhancing superoxide dismutase (SOD) activity and decreasing malondialdehyde (MDA) concentration. Galangin also reduced matrix metalloproteinase-2 (MMP-2), m metalloproteinase-9 (MMP-9) levels, promoting mucosal repair. At the cellular level, galangin decreased intracellular calcium ion concentration and mitigated the decline in mitochondrial membrane potential, enhance the restoration of mucosal cells, increased migration and proliferation, and reduced apoptosis. Molecularly, galangin demonstrated favorable binding to TRPV1, NGF, TRKA, TGF-β, COX-2, and NF-κB, and reversed the elevated expression of these proteins. Additionally, galangin downregulated the mRNA expression of TRPV1, CaM, SP, CGRP, BAX, and Caspase-3 in gastric tissues/cells, while upregulating Bcl-2 mRNA expression.

CONCLUSION

Galangin mitigates AGMI by inhibiting the overactivation of the TRPV1 pathway, thereby blocking aberrant signal transduction. This study suggests that galangin has therapeutic potential against ethanol-induced AGMI and may be a viable alternative for the treatment of alcohol-induced gastric mucosal injuries.

Research on drug treatment and the novel signaling pathway of chronic atrophic gastritis

BACKGROUND

Chronic atrophic gastritis (CAG) is a global digestive system disease and one of the important causes of gastric cancer. The incidence of CAG has been increasing yearly worldwide.

PURPOSE

This article reviews the latest research on the common causes and future therapeutic targets of CAG as well as the pharmacological effects of corresponding clinical drugs. We provide a detailed theoretical basis for further research on possible methods for the treatment of CAG and reversal of the CAG process.

RESULTS

CAG often develops from chronic gastritis, and its main pathological manifestation is atrophy of the gastric mucosa, which can develop into gastric cancer. The drug treatment of CAG can be divided into agents that regulate gastric acid secretion, eradicate Helicobacter. pylori (H. pylori), protect gastric mucous membrane, or inhibit inflammatory factors according to their mechanism of action. Although there are limited specific drugs for the treatment of CAG, progress is being made in defining the pathogenesis and therapeutic targets of the disease. Growing evidence shows that NF-κB, PI3K/AKT, Wnt/ β-catenin, MAPK, Toll-like receptors (TLRs), Hedgehog, and VEGF signaling pathways play an important role in the development of CAG.

Essential Oils: Chemistry and Pharmacological Activities-Part II

The importance of essential oils and their components in the industrial sector is attributed to their chemical characteristics and their application in the development of products in the areas of cosmetology, food, and pharmaceuticals. However, the pharmacological properties of this class of natural products have been extensively investigated and indicate their applicability for obtaining new drugs. Therefore, this review discusses the use of these oils as starting materials to synthesize more complex molecules and products with greater commercial value and clinic potential. Furthermore, the antiulcer, cardiovascular, and antidiabetic mechanisms of action are discussed. The main mechanistic aspects of the chemopreventive properties of oils against cancer are also presented. The data highlight essential oils and their derivatives as a strategic chemical group in the search for effective therapeutic agents against various diseases.

Prospective Randomized Controlled Clinical Trial of the Long-Term Effects of Omeprazole on Healthy Dogs

The use of omeprazole as a preventive treatment for gastrointestinal ulcers in veterinary medicine has been questioned during previous years. The aim of the present study is to assess the long-term effect of omeprazole on cobalamin and serum gastrin levels in healthy dogs. Eighteen healthy dogs were included: 10 in the control group and 8 in the omeprazole group. Three samples were collected: before starting the treatment (T0), 30 days after the start of treatment (T1), and at 60 days (T2). The mean cobalamin value (ng/L) in the control group was 481.4 (±293.70) at T0, 481.4 (±170.21) at T1, and 513.2 (±174.50) at T2. In the omeprazole group, the values were 424.62 (±161.57) at T0, 454.5 (±160.96) at T1, and 414.87 (±127.90) at T2. No statistically significant changes were detected in cobalamin levels between the three-time period in both study groups. These results agree with previous findings in felines but contrast with human medicine studies. The median gastrin values (pg/mL) in the control group were 62.45 [30.17-218.75] at T0, 76.06 [30.67-199.87] at T1, and 63.02 [35.81-176.06] at T2. The median gastrin value in the omeprazole group was 67.59 [55.96-101.60] at T0, 191.77 [75.31-1901.77] at T1, and 128.16 [43.62-1066.46] at T2. Statistically significant differences were detected (p = 0.008), indicating an increase in gastrin levels after initiating treatment with omeprazole. In conclusion, the increased levels of gastrin observed in this population underscore the importance of conducting a comprehensive clinical assessment to identify potential gastrointestinal disorders, particularly in consideration of the usage of omeprazole as a preventive treatment.

Organoid-Based Human Stomach Micro-Physiological System to Recapitulate the Dynamic Mucosal Defense Mechanism

Several stomach diseases are attributed to the dysregulation of physiological function of gastric mucosal barrier by pathogens. Gastric organoids are a promising tool to develop treatment strategies for gastric infections. However, their functional features of in vivo gastric mucosal barrier and host-microbe interactions are limited due to the lack of physiological stimuli. Herein, a human stomach micro-physiological system (hsMPS) with physiologically relevant gastric mucosal defense system is described based on the combination of organoid and MPS technology. A fluid flow enhanced epithelial-mesenchymal interaction in the hsMPS enables functional maturation of gastric epithelial cells, which allows for the recreation of mesh-like mucus layer containing high level of mucus protective peptides and well-developed epithelial junctional complexes. Furthermore, gastroprotection mechanisms against Helicobacter pylori (H. pylori) are successfully demonstrated in this system. Therefore, hsMPS represents a new in vitro tool for research where gastric mucosal defense mechanism is pivotal for developing therapeutic strategies.

The effect of combining basil seeds and gum Arabic on the healing process of experimental acetic acid-induced ulcerative colitis in rats

Background & aim

Ulcerative colitis (UC) is a chronic recurrent inflammatory disease of the large intestine and rectum that oxidative stress and severe inflammation are the main features of this disease. Previous studies have shown that separate consumption of basil and gum arabic can reduce inflammation and oxidative stress. The aim of the study was evaluating the effect of treatment with basil seeds given together with gum arabic on healing, inflammation and oxidative stress in the course of experimental colitis in rats.

Experimental procedure

A total number of 50 male rats were used, randomly assigned to five groups of 10 rats each. Colitis was induced in rats by enemas with 4% solution od acetic acid. Four days after induction of colitis, rats were treated for next 4 days with saline or combination of basil seeds plus gum arabic (1 mg/kg) or sulfasalazine (100 mg/g) rectally. The experiment was terminated after last dose of treatment. Rats without induction of colitis were used as a sham group.

Results

Acetic acid-induced colitis increased the macroscopic and histopathological damage scores of the colon as well as colon levels of MDA(Malondialdehyde), MPO(Myeloperoxidase), TNFα(Tissue necrosis factor α), IL6 (Interleukin 6)and IL17(Interleukin 17) and decreased SOD(Superoxide Dismutase), GPx (Glutathione Peroxidase) and IL10 (Interleukin 10) levels compared with the control group(P < 0.001). Treatment with basil and gum arabic reduced macroscopic and histopathological damage scores (P < 0.01) of the colon, MDA, MPO, TNFα, IL6(P < 0.001) and IL17 (P < 0.01) levels of the colon and increased SOD, GPx and IL10 levels compared to the colitis group (P < 0.01).

Conclusion

Rectal administration of combination of basil seeds plus gum arabic after induction of colitis, exhibits antioxidant and anti-inflammatory effects, and accelerates the healing of the colon in experimental colitis evoked by acetic acid.

Evaluation of proton pump inhibitor administration in hospitalized dogs in a tertiary referral hospital

BACKGROUND

Although proton pump inhibitors (PPIs) are commonly administered to hospitalized dogs, prescribing patterns and appropriateness of use require continued investigation.

HYPOTHESIS/OBJECTIVE

Describe prescription patterns and appropriateness of use associated with PPIs in hospitalized dogs at a single tertiary care facility. We hypothesized that the majority of prescriptions would not comply with current guidelines for the rational use of acid suppressants.

ANIMALS

Two hundred randomly selected hospitalized dogs.

METHODS

Retrospective evaluation of the medical records associated with a randomly selected sample of hospitalized dogs that received PPIs between January 2013 and December 2018.

RESULTS

A total of 12 610 dogs were admitted for first-time hospitalization between January 2013 and December 2018. Forty percent of these dogs (5062/12610) were prescribed a PPI PO or IV. Of the 200 randomly selected records, an adequate indication for use was identified in 27% of dogs (54/200). Of the dogs surviving to discharge, 54% (95/175) were discharged with a PPI and 51.6% (49/95) of those were prescribed an inadequate dose.

CONCLUSIONS AND IMPORTANCE

Our findings support other studies in which the majority of PPI prescriptions for hospitalized dogs at a tertiary care hospital lacked an appropriate indication. Furthermore, analysis of the prescribing patterns of dispensed PPIs identified a frequent occurrence of dosages considered inadequate, raising concern for ineffective treatment even with appropriate indications of use. With growing concern of adverse effects associated with PPI and other acid suppressant administration in human and veterinary medicine, rational use of these medications following consensus guidelines should be emphasized and treatment should be reserved for dogs with historical, physical examination, clinicopathologic, and imaging findings supportive of an appropriate indication for use.

Improved Image Analysis for Measuring Gastric Ulcer Index in Animal Models and Clinical Diagnostic Data

Gastric ulcers are one of the most common gastrointestinal diseases. In this study, as an attempt to reduce the minimal error in clinical observations during the diagnosis of gastric ulcers, the applicability of improved ImageJ analysis (IA) was investigated by comparing the results of animal experiments and clinical data. As a result, IA exhibited a significantly improved potential for determining the ulcer index (UI) of clinical data sheets compared to those rated directly by conventional clinical observation (CCO). This indicated that IA enhanced the reproducibility of the measurement of gastric UI using a Bland-Altman plot, resulting in a reduced deviation of each UI value. In addition, it was confirmed that errors in gastric UI decisions can be reduced by adjusting RGB values in diagnostic clinical data (i.e., adjusting to 100 is relatively better than adjusting to 50 or 200). Together, these results suggest that the new enhanced IA could be compatible with novel applications for measuring and evaluating gastric ulcers in clinical settings, meaning that the developed method could be used not only as an auxiliary tool for CCO, but also as a pipeline for ulcer diagnosis.

Role of the posterior mucosal defense barrier in portal hypertensive gastropathy

Portal hypertensive gastropathy (PHG) is a complication of cirrhotic or noncirrhotic portal hypertension. PHG is very important in the clinic because it can cause acute or even massive blood loss, and its treatment efficacy and prognosis are poor. Currently, the incidence of PHG in patients with cirrhosis is 20-80%, but its pathogenesis is complicated and poorly understood. Studies have shown that portal hypertension can cause changes in gastric mucosal microcirculation hemodynamics, leading to changes in gastric mucosal histology and function and thereby weakening the mucosal defense barrier. However, no specific drug treatment plans are currently available. This article reviews the current literature to further our understanding of the mechanism underlying PHG and the relationship between PHG and the posterior mucosal defense barrier and to explore new therapeutic targets.

Rutaecarpine Ameliorates Ethanol-Induced Gastric Mucosal Injury in Mice by Modulating Genes Related to Inflammation, Oxidative Stress and Apoptosis

Background: Rutaecarpine (RUT), a major quinazolino carboline alkaloid compound from the dry unripe fruit Tetradium ruticarpum (A. Juss.) T. G. Hartley, has various pharmacological effects. The aim of this present study was to investigate the potential gastroprotective effect of rutaecarpine on ethanol-induced acute gastric mucosal injury in mice and associated molecular mechanisms, such as activating Nrf2 and Bcl-2 via PI3K/AKT signaling pathway and inhibiting NF-κB.

Methods: Gastric ulcer index and histopathology was carried out to determine the efficacy of RUT in gastric ulceration, and the content of SOD, GSH in serum and CAT, MDA, MPO, TNF-α, IL-6, IL-1β in tissue were measured by kits. Besides, in order to illustrate the potential inflammatory, oxidative, and apoptotic perturbations, the mRNA levels of NF-κB p65, PI3K, AKT, Nrf2, Nqo1, HO-1, Bcl-2 and Bax were analyzed. In addition, the protein expression of NF-κB p65 and Nrf2 in cytoplasm and nucleus, AKT, p-AKT, Bcl-2 Bax and Caspase 3 were analyzed for further verification. Finally, immunofluorescence analysis was performed to further verify nuclear translocation of NF-κB p65.

Results: Current data strongly demonstrated that RUT alleviated the gross gastric damage, ulcer index and the histopathology damage caused by ethanol. RUT inhibited the expression and nuclear translocation of NF-κB p65 and the expression of its downstream signals, such as TNF-α, IL-6, IL-1β and MPO. Immunofluorescence analysis also verifies the result. In the context of oxidative stress, RUT improved the antioxidant milieu by remarkably upregulating the expression Nqo1 and HO-1 with activating Nrf2, and could remarkably upregulate antioxidant SOD, GSH, CAT and downregulate levels of MDA. Additionally, RUT activate the expression of Bcl-2 and inhibited the expression of downstream signals Bax and Caspase 3 to promote gastric cellular survival. These were confirmed by RUT activation of the PI3K/AKT pathway manifested by enhanced expression of PI3K and promotion of AKT phosphorylation.

Conclusion: Taken together, these results strongly demonstrated that RUT exerted a gastroprotective effect against gastric mucosal injury induced by ethanol. The underlying mechanism might be associated with the improvement of anti-inflammatory, anti-oxidation and anti-apoptosis system.

The gastroprotective effect of obestatin on indomethacin-induced acute ulcer is mediated by a vagovagal mechanism

In order to investigate the role of the vagus nerve in the possible gastroprotective effect of obestatin on the indomethacin-induced acute oxidative gastric injury, Sprague-Dawley rats of both sexes were injected subcutaneously with indomethacin (25 mg/kg, 5% NaHCO3) followed by obestatin (10, 30 or 100 μg/kg). In other sets of rats, surgical vagotomy (Vx) or selective degeneration of vagal afferent fibers by perivagal capsaicin was performed before the injections of indomethacin or indomethacin + obestatin (30 μg/kg). Gastric serosal blood flow was measured, and 4 h after ulcer induction gastric tissue samples were taken for histological and biochemical assays. Obestatin reduced the severity of indomethacin-induced acute ulcer via the reversal of reactive hyperemia, by inhibiting ulcer-induced neutrophil infiltration and lipid peroxidation along with the replenishment of glutathione (GSH) stores, whereas Vx abolished the inhibitory effect of obestatin on blood flow and lipid peroxidation, and worsened the severity of ulcer. On the other hand, serosal blood flow was even amplified by the selective denervation of the capsaicin-sensitive vagal afferent fibers, but obestatin-induced reduction in ulcer severity was not altered. In conclusion, the gastroprotective effect of obestatin on indomethacin-induced ulcer appears to involve the activation of the vagovagal pathway.

Effects of intracerebroventricularly injected glucagon-like peptide-2 on ethanol-induced gastric mucosal damage in rats

PURPOSE

The present study aims to investigate the effects of intracerebroventricularly (i.c.v.)-injected glucagon-like peptide-2 (GLP-2) on ethanol-induced gastric mucosal damage and to reveal the mechanisms involved in this effect.

MATERIALS AND METHODS

Rats received absolute ethanol orally via an orogastric tube 30 minutes after GLP-2 (1-200 ng/10 µl; i.c.v.) or saline (10 µl) injections. They were decapitated 1 hour later, their stomachs were removed, and the gastric mucosal damage was scored.

RESULTS

A total of 100 ng GLP-2 inhibited the gastric mucosal damage by 67%. This effect was abolished by the calcitonin gene-related peptide (CGRP) receptor antagonist CGRP-(8-37) (10 µg/kg; s.c.), but was not affected by either the nitric oxide (NO) synthase inhibitor L-NAME (30 mg/kg; s.c.) or the cyclooxygenase inhibitor indomethacin (5 mg/kg; i.p.). The most effective gastroprotective dose of GLP-2 (100 ng/10 µl; i.c.v.), but not the higher doses (150 or 200 ng/10 µl; i.c.v.) prevented the decrease in gastric mucosal blood flow caused by ethanol. In conclusion, i.c.v. GLP-2 protects against ethanol-induced gastric mucosal damage and this effect is mediated by CGRP receptor activation and gastric mucosal blood flow, but not by NO or prostaglandins.

STORE-gastrointestinal functions and gastrointestinal hormones in patients with liver failure

This study aims to investigate the gastrointestinal functions of patients with liver failure (LF) based on gastrointestinal dysfunction (GD) scores and serum gastrointestinal hormone levels.The GD in LF patients was scored using the gastrointestinal dysfunction scoring criteria. Serum gastrin (GAS), cholecystokinin (CCK), and motilin (MTL) levels were determined in LF patients. In addition, liver function and prothrombin activity were detected, and ultrasonography was performed.The GD score was significantly higher in the LF groups than in the control group. Compared with the control group, serum GAS, CCK, and MTL levels significantly increased in the LF groups, and was positively correlated with the severity of LF. Furthermore, in the LF groups, GD was positively correlated with the severity of LF. However, the GD score and serum GAS, CCK, and MTL levels in the acute LF group were not statistically different, when compared with those in the subacute LF group, acute-on-chronic LF group and chronic LF group.LF plays a key role in the development of GD, and may be the main cause of obvious gastrointestinal symptoms, such as abdominal distension, nausea, vomiting and anorexia, in LF patients. The severity of GD is not associated with LF type, but is positively correlated with the severity of LF, suggesting that GD in LF patients may have complicated mechanisms.

Acid and the basis for cellular plasticity and reprogramming in gastric repair and cancer

Subjected to countless daily injuries, the stomach still functions as a remarkably efficient digestive organ and microbial filter. In this Review, we follow the lead of the earliest gastroenterologists who were fascinated by the antiseptic and digestive powers of gastric secretions. We propose that it is easiest to understand how the stomach responds to injury by stressing the central role of the most important gastric secretion, acid. The stomach follows two basic patterns of adaptation. The superficial response is a pattern whereby the surface epithelial cells migrate and rapidly proliferate to repair erosions induced by acid or other irritants. The stomach can also adapt through a glandular response when the source of acid is lost or compromised (that is, the process of oxyntic atrophy). We primarily review the mechanisms governing the glandular response, which is characterized by a metaplastic change in cellular differentiation known as spasmolytic polypeptide-expressing metaplasia (SPEM). We propose that the stomach, like other organs, exhibits marked cellular plasticity: the glandular response involves reprogramming mature cells to serve as auxiliary stem cells that replace lost cells. Unfortunately, such plasticity might mean that the gastric epithelium undergoes cycles of differentiation and de-differentiation that increase the risk of accumulating cancer-predisposing mutations.

Polyphenols in Kuding tea help prevent HCl/ethanol-induced gastric injury in mice

We conducted the present study to determine the gastric injury preventive effects of polyphenols in Kuding tea (KTPs) in Kunming (KM) mice through the inhibition of gastric-acid secretion and the protection of the gastric mucosa.

Women Who Sleep More Have Reduced Risk of Peptic Ulcer Disease; Korean National Health and Nutrition Examination Survey (2008-2009)

Sleep is integral to life and sleep duration is important in sleep quality, physical, and psychological health. Disturbances in sleep duration have been associated with increased risk of metabolic disorders, hypertension, and overall mortality. Sleep disturbance has also been linked with various gastrointestinal disorders. However, the association between sleep and peptic ulcer disease (PUD) has not been evaluated. We investigated the association between sleep duration and PUD. Subjects were included from the fifth Korean National Health and Nutrition Examination Survey conducted from 2008-2009. Individuals with PUD were defined as those with a physician diagnosis of PUD. Daily sleep duration was established by asking participants the amount of time that they slept per day. Multiple logistic regression models were used to evaluate the association of PUD and sleep duration. This study included 14,290 participants (8,209 women). The prevalence of PUD was 5.7% and was higher in men (6.8%) than in women (4.9%). Women who slept ≥9 hours were significantly less likely to have PUD compared to women who slept 7 hours. In men, longer sleep duration (≥9 hours) had a tendency toward PUD prevention. Our results suggest that longer sleep duration may play a protective role for PUD development.

The Gastrointestinal Circulation: Physiology and Pathophysiology

The gastrointestinal (GI) circulation receives a large fraction of cardiac output and this increases following ingestion of a meal. While blood flow regulation is not the intense phenomenon noted in other vascular beds, the combined responses of blood flow, and capillary oxygen exchange help ensure a level of tissue oxygenation that is commensurate with organ metabolism and function. This is evidenced in the vascular responses of the stomach to increased acid production and in intestine during periods of enhanced nutrient absorption. Complimenting the metabolic vasoregulation is a strong myogenic response that contributes to basal vascular tone and to the responses elicited by changes in intravascular pressure. The GI circulation also contributes to a mucosal defense mechanism that protects against excessive damage to the epithelial lining following ingestion of toxins and/or noxious agents. Profound reductions in GI blood flow are evidenced in certain physiological (strenuous exercise) and pathological (hemorrhage) conditions, while some disease states (e.g., chronic portal hypertension) are associated with a hyperdynamic circulation. The sacrificial nature of GI blood flow is essential for ensuring adequate perfusion of vital organs during periods of whole body stress. The restoration of blood flow (reperfusion) to GI organs following ischemia elicits an exaggerated tissue injury response that reflects the potential of this organ system to generate reactive oxygen species and to mount an inflammatory response. Human and animal studies of inflammatory bowel disease have also revealed a contribution of the vasculature to the initiation and perpetuation of the tissue inflammation and associated injury response.

Protective Factors of the Gastric and Duodenal Mucosa: An Overview

The structural and functional integrity of the gastric and duodenal mucosa represents equilibrium between aggressive factors and protective mechanisms. Mucus-buffers-phospholipid layer as pre-epithelial barrier, enhanced by prostaglandins and epidermal growth factor, remains a vanguard of mucosal protection. It maintains a neutral pH at the surface epithelial luminal interface, facing luminal pH dropping to 1.0, i.e., hydrogen ion concentration gradient equal 1,000,000. The surface epithelial cells, elaborating mucins, buffers, phospholipids, prostaglandins, trefoil peptides, peptide growth factor and their receptors, heat shock proteins, cathelicidins, and β-defensins form the second line of defense. Endothelium exerts mucosal protection through production of potent vasodilators like nitric oxide and prostacyclins and through release of angiogenic growth factors, securing adequate blood flow and representing the third and an ultimate line of mucosal protection. This microcirculation is instrumental for supply of oxygen, nitric oxide, hydrogen sulfide and removal of ad hoc generated toxic substances as well as for continuous mucosal cell renewal from progenitor cells, secured by growth factors accompanied by survivin preventing early apoptosis.

Decreased vascular endothelial growth factor expression is associated with cell apoptosis in low-dose aspirin-induced gastric mucosal injury

BACKGROUND

The use of low-dose aspirin (LDA) has emerged as an important cause of gastrointestinal ulcers. The aim of this study was to investigate the association between LDA-induced gastric mucosal injury and the expression of vascular endothelial growth factor (VEGF) and cell apoptosis in elderly Chinese patients.

METHODS

A total of 136 patients aged 60 to 80 years with LDA-induced (100 mg/d for at least 1 month) gastric mucosal injury and 48 age-matched healthy subjects were enrolled in this study. The patients were divided into a low-severity group and a high-severity group based on their modified Lanza scale scores. Biopsy specimens of gastric mucosa from all participants were subjected to immunohistochemical staining for VEGF expression and terminal deoxynucleotidyl transferase dUTP nick end labeling staining for cell apoptosis. Staining indices and apoptotic indices were applied to assess VEGF expression level and the extent of cell apoptosis.

RESULTS

VEGF expression decreased significantly in the 2 patient groups, whereas the extent of cell apoptosis significantly increased compared with the control group. Furthermore, Spearman's correlation coefficients suggest that VEGF expression levels and the extent of cell apoptosis in gastric mucosae shared a significant correlation with the severity of LDA-induced gastric mucosal injury. Receiver operating characteristics analysis further confirmed these results.

CONCLUSIONS

Our findings provide important clues as to the underlying molecular mechanism behind gastric mucosal injury resulting from exposure to LDA in elderly adults, and also suggest that interventions specifically targeting the pathways associated with angiogenesis and apoptosis may help facilitate the healing process.

Pyruvate Is Superior to Citrate in Oral Rehydration Solution in the Protection of Intestine via Hypoxia-Inducible Factor-1 Activation in Rats With Burn Injury

BACKGROUND

Recent studies have suggested that pyruvate-enriched oral rehydration solution (Pyr-ORS) may be superior to the standard bicarbonate-based ORS in the protection of intestine from ischemic injury. The aim of this study was to compare the effects of Pyr-ORS with citrate-enriched ORS (Cit-ORS) on the intestinal hypoxia-inducible factor-1 (HIF-1)-erythropoietin (EPO) signaling pathway for enteral rehydration in a rat model of burn injury.

METHODS

Rats were randomly assigned to 4 groups (N = 20, 2 subgroups each: n = 10): scald sham (group SS), scald with no fluid resuscitation (group SN), scald and resuscitation with enteral Cit-ORS (group SC), and scald and resuscitation with enteral Pyr-ORS (group SP). At 2.5 and 4.5 hours after a 35% total body surface area (TBSA) scald, intestinal mucosal blood flow (IMBF), contents of HIF-1, EPO, endothelial nitric oxide synthase (eNOS), nitric oxide (NO), barrier protein (ZO-1), levels of serum diamine oxidase (DAO), and intestinal mucosal histology injury score were determined.

RESULTS

Serum DAO activities in the scalded groups were significantly elevated, but less raised in group SP than in group SC, at 2.5 hours and at 4.5 hours after the scald. Further, group SP more profoundly preserved intestinal HIF-1 expression compared with group SC at the 2 time points. Compared with group SC, group SP had markedly elevated intestinal EPO, eNOS, and NO levels at the same time points, respectively (P < .05). Similarly, IMBF and ZO-1 levels were significantly higher in group SP than in group SC. Intestinal mucosal histopathological scores were statistically higher at 2.5 hours and 4.5 hours after scalding but were more attenuated in group SP than in group SC (P < .05). Immunofluorescence expression of intestinal mucosal ZO-1 was consistent with the above changes. The above parameters were also significantly different between groups SC and SN (all P < .05).

CONCLUSION

Pyr-ORS provides a superior option to Cit-ORS for the preservation of intestinal blood flow and barrier function and the attenuation of histopathological alterations in enteral resuscitation of rats with burn injury. Its underlying mechanism may be closely related to the pyruvate in activation of intestinal HIF-1-EPO signaling cascades.

The protective activity of Conyza blinii saponin against acute gastric ulcer induced by ethanol

ETHNOPHARMACOLOGICAL RELEVANCE

Conyza blinii H.Lév., is a type of natural plant. Its dried overground section is used to treat infections and inflammations in traditional Chinese medicine. Triterpenoidal saponins have a wide range of bioactivities, for instance, anti-cancer, anti-virus and anti-anaphylaxis. Conyza blinii saponin (CBS), mainly composed of triterpenoidal saponins, is the total saponin of Conyza blinii H.Lév. It has been reported that CBS also has gastric mucous membrane protection activity. This study aims to test CBS׳s protective activity of gastric׳s mucous membrane against ethanol. This investigation may lead to the development of novel drug from natural products as anti-ulcer agent, or as gastric mucous protective against chemical damage.

MATERIALS AND METHODS

CBS (Conyza blinii saponin) is the total saponin of Conyza blinii H.Lév., which was obtained as described previously. We tested the protective activity of CBS against ethanol-induced ulcer. Thirty six rats were grouped randomly as 'NORMAL', 'CONTROL', 'MODEL', 'LOW DOSE', 'MEDIUM DOSE' and 'HIGH DOSE'. The 'NORMAL' group were rats with no pathological model established within it. The 'CONTROL' group was administrated with colloidal bismuth subcitrate, while 'MODEL' group was not given any active agents apart from absolute ethanol in order to obtain gastric ulcer model. The three 'DOSE' groups were treated with different concentrations of CBS (5, 10, 20mg/mL) before administration followed by absolute ethanol. All rats were sacrificed after the experiment to acquire the gastric tissue. The ulcer index (UI), malondialdehyde (MDA) and superoxide dismutase (SOD) were measured to monitor the activity of CBS. Besides, the rat gastric tissue was made to paraffin section and stained using the Hematoxylin-Eosin (HE) method. The histopathology examination was carried out to examine CBS efficacy in terms of gastric mucous protection.

RESULTS

We found that CBS had a profound protection activity against acute gastric ulcer induced by ethanol and this activity displayed a concentration-dependent manner. The efficacy of 10 and 20mg/mL CBS was comparable with colloidal bismuth subcitrate (P<0.05). All three level of CBS tested were able to significantly reduce UI, MDA and enhance SOD level (P<0.05).

CONCLUSIONS

It was deduced that the mechanism for such activity would be anti-lipid peroxidation, facilitating free radicals clearance. In addition , histopathology examination of the gastric mucous membrane supported the same conclusion, that CBS can efficiently suppress the inflammatory reactions, bleeding and protect the gastric mucosa.

Role of gastric acid inhibition, prostaglandins and endogenous-free thiol groups on the gastroprotective effect of a proteolytic fraction from Vasconcellea cundinamarcensis latex

OBJECTIVES

The aim of this study was to extend our knowledge about the mechanism involved in the gastroprotective effect of P1G10, a proteolytic fraction rich in cysteine proteinases from Vasconcellea cundinamarcensis (syn. Carica candamarcensis) latex, which demonstrated gastric healing and protection activities in rats.

METHODS

Wistar rats were submitted to gastric lesions by indomethacin and treated with P1G10 (10 mg/kg). Free thiol groups and prostaglandin E2 content were measured in gastric mucosal and gastrin levels in blood samples. To evaluate the participation of nitric oxide (NO) or proteolytic activity of P1G10 on its gastroprotective effect, animals were treated with an inhibitor of NO production (L-NAME) or the fraction inhibited by iodoacetamide, respectively. Gastric secretion study (acidity and pepsin activity) was also performed.

KEY FINDINGS

P1G10 (10 mg/kg) inhibited the occurrence of gastric lesions by indomethacin, restored the free thiol groups content on gastric mucosa and increased moderately prostaglandin E2 levels (34%). Furthermore, the treatment decreased the gastrin levels (95%), suggesting a possible modulation of secretory activity. This effect was accordant with attenuation of gastric acidity (42%) and pepsin activity (69%) seen in animals subjected to pyloric ligation. The inhibition of NO production or the proteolytic activity of P1G10 does not affect the gastroprotective effect.

CONCLUSIONS

These results can explain the gastroprotective activity of P1G10 and serve a basis for further studies of this active principle.

Enhanced analgesic properties and reduced ulcerogenic effect of a mononuclear copper(II) complex with fenoprofen in comparison to the parent drug: promising insights in the treatment of chronic inflammatory diseases

Analgesic and ulcerogenic properties have been studied for the copper(II) coordination complex of the nonsteroidal anti-inflammatory drug Fenoprofen and imidazole [Cu(fen)2(im)2] (Cu: copper(II) ion; fen: fenoprofenate anion from Fenoprofen, im: imidazole). A therapeutic dose of 28 mg/kg was tested for [Cu(fen)2(im)2] and 21 mg/kg was employed for Fenoprofen calcium, administered by oral gavage in female mice to compare the therapeutic properties of the new entity. The acetic acid induced writhing test was employed to study visceral pain. The percentage of inhibition in writhing and stretching was 78.9% and 46.2% for the [Cu(fen)2(im)2] and Fenoprofen calcium, respectively. This result indicates that the complex could be more effective in diminishing visceral pain. The formalin test was evaluated to study the impact of the drugs over nociceptive and inflammatory pain. The complex is a more potent analgesic on inflammatory pain than the parent drug. Ulcerogenic effects were evaluated using a model of gastric lesions induced by hypothermic-restraint stress. Fenoprofen calcium salt caused an ulcer index of about 79 mm(2) while the one caused by [Cu(fen)2(im)2] was 22 mm(2). The complex diminished the development of gastric mucosal ulcers in comparison to the uncomplexed drug. Possible mechanisms of action related to both therapeutic properties have been discussed.

Nutrients affecting gastric barrier

The gastric barrier could be considered an active tissue involved in many synthetic and metabolic functions, as the immunological defense, by activating mucosal immune system. Barrier integrity results from a balance between protective and aggressive endogenous factors and from their interaction with exogenous factors (steroidal or nonsteroidal anti-inflammatory drugs, dietary nitrates, nitrites and/or NaCl, stress, Helicobacter pylori infection, food allergens and contaminants, metals, chemicals, radiation, smoking and alcohol intake). Nutrients represent the most important exogenous factors affecting gastric barrier because of the impact on people's everyday life. We report evidence from the literature about nutrients affecting gastric barrier and we investigate the possible effect that nutrients can play to determining or maintaining a gastric barrier dysfunction.

Oxidative stress induces gastric submucosal arteriolar dysfunction in the elderly

AIM: To evaluate human gastric submucosal vascular dysfunction and its mechanism during the aging process.

METHODS: Twenty male patients undergoing subtotal gastrectomy were enrolled in this study. Young and elderly patient groups aged 25-40 years and 60-85 years, respectively, were included. Inclusion criteria were: no clinical evidence of cardiovascular, renal or diabetic diseases. Conventional clinical examinations were carried out. After surgery, gastric submucosal arteries were immediately dissected free of fat and connective tissue. Vascular responses to acetylcholine (ACh) and sodium nitroprusside (SNP) were measured by isolated vascular perfusion. Morphological changes in the gastric mucosal vessels were observed by hematoxylin and eosin (HE) staining and Verhoeff van Gieson (EVG) staining. The expression of xanthine oxidase (XO) and manganese-superoxide dismutase (Mn-SOD) was assessed by Western blotting analysis. The malondialdehyde (MDA) and hydrogen peroxide (H₂O₂) content and the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were determined according to commercial kits.

RESULTS: The overall structure of vessel walls was shown by HE and EVG staining, respectively. Disruption of the internal elastic lamina or neointimal layers was not observed in vessels from young or elderly patients; however, cell layer number in the vessel wall increased significantly in the elderly group. Compared with submucosal arteries in young patients, the amount of vascular collagen fibers, lumen diameter and media cross-sectional area were significantly increased in elderly patients. Ach- and SNP-induced vasodilatation in elderly arterioles was significantly decreased compared with that of gastric submucosal arterioles from young patients. Compared with the young group, the expression of XO and the contents of MDA and H₂O₂ in gastric submucosal arterioles were increased in the elderly group. In addition, the expression of Mn-SOD and the activities of SOD and GSH-Px in the elderly group decreased significantly compared with those in the young group.

CONCLUSION: Gastric vascular dysfunction and senescence may be associated with increased oxidative stress and decreased antioxidative defense in the aging process.

Brainstem neuropeptides and vagal protection of the gastric mucosal against injury: role of prostaglandins, nitric oxide and calcitonin-gene related peptide in capsaicin afferents

Earlier experimental studies indicated that the integrity of vagal pathway was required to confer gastric protection against damaging agents. Several peptides located in the brainstem initially identified to influence vagal outflow to the stomach, as assessed by electrophysiological approach or by vagal dependent alterations of gastric secretory and motor function, were investigated for their influence in the vagal regulation of the resistance of the gastric mucosa to injury. Thyrotropin releasing hormone (TRH), or its stable TRH analog, RX-77368, injected at low doses into the cisterna magna or the dorsal motor nucleus (DMN) was the first peptide reported to protect the gastric mucosa against ethanol injury through stimulation of vagal cholinergic pathways, inducing the release of gastric prostaglandins/nitric oxide (NO) and the recruitment of efferent function of capsaicin sensitive afferent fibers containing calcitonin-gene related peptide (CGRP). Activation of endogenous TRH-TRH1 receptor signaling located in the brainstem plays a role in adaptive gastric protection against damaging agents. Since then, an expanding number of peptides, namely peptide YY, CGRP, adrenomedullin, amylin, glugacon-like peptide, opioid peptides acting on µ, δ1 or δ2 receptors, nocicpetin, nocistatin, ghrelin, leptin and TLQP-21, a peptide derived from VGF prohormone, have been reported to act in the brainstem to afford gastric protection against ethanol injury largely through similar peripheral effectors mechanisms than TRH. Therefore gastric prostaglandins and CGRP/NO pathways represent a common final mechanism through which brain peptides confer vagally mediated gastroprotection against injury. A better understanding of brain circuitries through which these peptides are released will provide new strategies to recruit integrated and multifaceted gastroprotective mechanisms.

[Diagnosis and management of acute mesenteric ischemia]

The prevalence of significant splanchnic arterial stenoses is increasing, but remains mostly asymptomatic due to abundant collateral circulation. Acute insufficiency of mesenteric arterial blood flow accounts for 60 to 70% of cases of mesenteric ischemia and results mostly from a superior mesenteric embolus. Despite major advances have been achieved in understanding the pathogenic mechanisms of bowel ischemia, its prognosis remains dismal with mortality rates about 60%. The diagnosis of acute mesenteric ischemia depends upon a high clinical suspicion, especially in patients with known risk factors. Rapid diagnosis is essential to prevent intestinal infarction. However, early signs and symptoms of mesenteric ischemia are non specific, and definitive diagnosis often requires radiologic examinations. Early and liberal implementation of angiography has been the major advance over the past 30 years which allowed increasing diagnostic accuracy of acute mesenteric ischemia. CT and MR-based angiographic techniques have emerged as alternatives less invasive and more accurate to analyse splanchnic vessels and evaluate bowel infarction. The goal of treatment of patients with acute mesenteric ischemia is to restore intestinal oxygenation as quickly as possible after initial management that includes rapid hemodynamic monitoring and support. Surgery should not be delayed in patients suspected of having intestinal necrosis.

Effects of intestinal mucosal blood flow and motility on intestinal mucosa

AIM: To investigate the role of intestinal mucosal blood flow (IMBF) and motility in the damage of intestinal mucosal barrier in rats with traumatic brain injury.

METHODS: Sixty-four healthy male Wistar rats were divided randomly into two groups: traumatic brain injury (TBI) group (n = 32), rats with traumatic brain injury; and control group (n = 32), rats with sham-operation. Each group was divided into four subgroups (n = 8) as 6, 12, 24 and 48 h after operation. Intestinal motility was measured by the propulsion ratio of a semi-solid colored marker (carbon-ink). IMBF was measured with the laser-Doppler technique. Endotoxin and D-xylose levels in plasma were measured to evaluate the change of intestinal mucosal barrier function following TBI.

RESULTS: The level of endotoxin was significantly higher in TBI group than in the control group at each time point (0.382 ± 0.014 EU/mL vs 0.102 ± 0.007 EU/mL, 0.466 ± 0.018 EU/mL vs 0.114 ± 0.021 EU/mL, 0.478 ± 0.029 EU/mL vs 0.112 ± 0.018 EU/mL and 0.412 ± 0.036 EU/mL vs 0.108 ± 0.011 EU/mL, P < 0.05). D-xylose concentrations in plasma in TBI group were significantly higher than in the control group (6.68 ± 2.37 mmol/L vs 3.66 ± 1.07 mmol/L, 8.51 ± 2.69 mmol /L vs 3.15 ± 0.95 mmol/L, 11.68 ± 3.24 mmol/L vs 3.78 ± 1.12 mmol/L and 10.23 ± 2.83 mmol/L vs 3.34 ± 1.23 mmol/ L, P < 0.05). The IMBF in TBI group was significantly lower than that in the control group (38.5 ± 2.8 PU vs 45.6 ± 4.6 PU, 25.2 ± 3.1 PU vs 48.2 ± 5.3 PU, 21.5 ± 2.7 PU vs 44.9 ± 2.8 PU, 29. 4 ± 3.8 PU vs 46.7 ± 3.2 PU) (P < 0.05). Significant decelerations of intestinal propulsion ratio in TBI groups were found compared with the control group (0.48% ± 0.06% vs 0.62% ± 0.03%, 0.37% ± 0.05% vs 0.64% ± 0.01%, 0.39% ± 0.07% vs 0.63% ± 0.05% and 0.46% ± 0.03% vs 0.65% ± 0.02%) (P < 0.05).

CONCLUSION: The intestinal mucosal permeability is increased obviously in TBI rats. Decrease of intestinal motility and IMBF occur early in TBI, both are important pathogenic factors for stress-related damage of the intestinal mucosal barrier in TBI.

Protective effect of anacardic acids from cashew (Anacardium occidentale) on ethanol-induced gastric damage in mice

Cashew nut-shell liquid and the contained anacardic acids (AAs) have been shown to possess antioxidant, lipoxygenase inhibitory, anti-Helicobacter pylori and antitumor properties. Despite these known effects, hitherto there were no published reports on their likely gastroprotective effects. The present study was designed to verify whether AAs afford gastroprotection against the ethanol-induced gastric damage and to examine the underlying mechanism(s). Gastric damage was induced by intragastric administration of 0.2mL of ethanol (96%). Mice in groups were pretreated orally with AAs (10, 30 and 100mg/kg), misoprostol (50 microg/kg), or vehicle (2% Tween 80 in saline, 10mL/kg), 45min before ethanol administration. They were sacrificed 30min later, the stomachs excised, and the mucosal lesion area (mm(2)) measured by planimetry. Gastroprotection was assessed in relation to inhibition of gastric lesion area. To study the gastroprotective mechanism(s), its relations to capsaicin-sensitive fibers, endogenous prostaglandins, nitric oxide and ATP-sensitive potassium channels were analysed. Treatments effects on ethanol-associated oxidative stress markers GSH, MDA, catalase, SOD, and total nitrate/nitrite levels as an index of NO were measured in gastric tissue. Besides, the effects of AAs on gastric secretory volume and total acidity were analysed in 4-h pylorus-ligated rat. AAs afforded a dose-related gastroprotection against the ethanol damage and further prevented the ethanol-induced changes in the levels of GSH, MDA, catalase, SOD and nitrate/nitrite. However, they failed to modify the gastric secretion or the total acidity. It was observed that the gastroprotection by AAs was greatly reduced in animals pretreated with capsazepine, indomethacin, l-NAME or glibenclamide. These results suggest that AAs afford gastroprotection principally through an antioxidant mechanism. Other complementary mechanisms include the activation of capsaicin-sensitive gastric afferents, stimulation of endogenous prostaglandins and nitric oxide, and opening of K(+)(ATP) channels. These combined effects are likely to be accompanied by an increase in gastric microcirculation.

Melatonin reduces indomethacin-induced gastric mucosal cell apoptosis by preventing mitochondrial oxidative stress and the activation of mitochondrial pathway of apoptosis

Augmentation of gastric mucosal cell apoptosis due to development of oxidative stress is one of the main pathogenic events in the development of nonsteroidal anti-inflammatory drug (NSAID)-induced gastropathy. Identification of a nontoxic, anti-apoptotic molecule is warranted for therapy against NSAID-induced gastropathy. The objective of the present study was to define the mechanism of the anti-apoptotic effect of melatonin, a nontoxic molecule which scavenges reactive oxygen species. Using an array of experimental approaches, we have shown that melatonin prevents the development of mitochondrial oxidative stress and activation of mitochondrial pathway of apoptosis induced by indomethacin (a NSAID) in the gastric mucosa. Melatonin inhibits the important steps of indomethacin-induced activation of mitochondrial pathway of apoptosis such as upregulation of the expression of Bax and Bak, and the downregulation of Bcl-2 and BclxL. Melatonin also prevents indomethacin-induced mitochondrial translocation of Bax and prevents the collapse of mitochondrial membrane potential. Moreover, melatonin reduces indomethacin-mediated activation of caspase-9 and caspase-3 by blocking the release of cytochrome c and finally rescues gastric mucosal cells from indomethacin-induced apoptosis as measured by the TUNEL assay. Histologic studies of gastric mucosa further document that melatonin almost completely protects against gastric damage induced by indomethacin. Thus, melatonin has significant anti-apoptotic effects to protect gastric mucosa from NSAID-induced apoptosis and gastropathy, which makes its use as potential therapy against gastric damage during NSAID treatment.

Acute effects of Helicobacter pylori extracts on gastric mucosal blood flow in the mouse

AIM: To investigate the mechanisms underlying the reduction in gastric blood flow induced by a luminal water extract of Helicobacter pylori (HPE).

METHODS: The stomachs of isoflurane-anesthetized mice were exteriorized, and the mucosal surface exposed. Blood flow was measured with the laser-Doppler technique, and systemic arterial blood pressure monitored. C57BL/6 mice were exposed to water extract produced from H pylori strain 88-23. To investigate the role of a nerve- or iNOS-mediated pathway, we used intraluminal lidocaine and iNOS-/- mice. Blood flow response to the endogenous nitric oxide synthase inhibitor asymmetric dimethyl arginine (ADMA) was also assessed.

RESULTS: In wild-type mice, HPE decreased mucosal blood flow by approximately 30%. This reduction was abolished in iNOS-deficient mice, and by pre-treatment with lidocaine. Luminally applied ADMA resulted in reduction in blood flow similar to that observed in wild-type mice exposed to HPE.

CONCLUSION: A H pylori water extract reduces gastric mucosal blood flow acutely through iNOS- and nerve-mediated pathways.

Diagnosis and management of splanchnic ischemia

Splanchnic or gastrointestinal ischemia is rare and randomized studies are absent. This review focuses on new developments in clinical presentation, diagnostic approaches, and treatments. Splanchnic ischemia can be caused by occlusions of arteries or veins and by physiological vasoconstriction during low-flow states. The prevalence of significant splanchnic arterial stenoses is high, but it remains mostly asymptomatic due to abundant collateral circulation. This is known as chronic splanchnic disease (CSD). Chronic splanchnic syndrome (CSS) occurs when ischemic symptoms develop. Ischemic symptoms are characterized by postprandial pain, fear of eating and weight loss. CSS is diagnosed by a test for actual ischemia. Recently, gastro-intestinal tonometry has been validated as a diagnostic test to detect splanchnic ischemia and to guide treatment. In single-vessel CSD, the complication rate is very low, but some patients have ischemic complaints, and can be treated successfully. In multi-vessel stenoses, the complication rate is considerable, while most have CSS and treatment should be strongly considered. CT and MR-based angiographic reconstruction techniques have emerged as alternatives for digital subtraction angiography for imaging of splanchnic vessels. Duplex ultrasound is still the first choice for screening purposes. The strengths and weaknesses of each modality will be discussed. CSS may be treated by minimally invasive endoscopic treatment of the celiac axis compression syndrome, endovascular antegrade stenting, or laparotomy-assisted retrograde endovascular recanalization and stenting. The treatment plan is highly individualized and is mainly based on precise vessel anatomy, body weight, co-morbidity and severity of ischemia.

Quebrachitol-induced gastroprotection against acute gastric lesions: role of prostaglandins, nitric oxide and K+ ATP channels

The effect of Quebrachitol (2-O-methyl-L-inositol), a bioactive component from Magonia glabrata fruit extract was investigated against gastric damage induced by absolute ethanol (96%, 0.2 ml/animal) and indomethacin (30 mg/kg, p.o.), in mice. Quebrachitol at oral doses of 12.5, 25, and 50mg/kg markedly attenuated the gastric lesions induced by ethanol to the extent of 69%, 64%, and 53% and against indomethacin by 55%, 59%, and 26%, respectively. While pretreatment with TRPV1 antagonist capsazepine (5mg/kg, i.p.) failed to block effectively the gastroprotective effect of quebrachitol (25mg/kg) against ethanol damage, the non-selective cyclooxygenase inhibitor indomethacin (10mg/kg, p.o.), almost abolished it. Furthermore, quebrachitol effect was significantly reduced in mice pretreated with L-NAME, or glibenclamide, the respective inhibitors of nitric oxide synthase and K(+)(ATP) channel activation. Thus we provide the first evidence that quebrachitol reduces the gastric damage induced by ethanol and indomethacin, at least in part, by mechanisms that involve endogenous prostaglandins, nitric oxide release, and or the activation of K(+)(ATP) channels.

Perfusional evaluation of postesophagectomy gastroplasty with a radioisotopic study

Anastomotic fistula represents one of the frequent causes of postoperative morbidity and mortality following transhiatal esophageal resections. The main etiological factor is the ischemia of the gastric tube created for digestive transit reconstruction. Evidence suggests that per operative hypoperfusion can be maintained or even impaired after the surgery. Several methods have been employed in an attempt to assess the blood perfusion of the gastric flap, but they all pose limitations. However, there is a chronological relationship between perfusion assessments, which are almost exclusively performed per operatively, and the occurrence of a leak, which commonly appears several days after the surgery. The authors have developed a method of gastric perfusion evaluation by single photon emission computed tomography scintigraphy, which corrects that temporal matter, allowing the estimation of postoperative gastric perfusion. It is noninvasive, low cost, and may be applied by the time frame when most fistulas occur. High correlation between the event fistula and the low radiotracer uptake in the group of studied patients could be demonstrated. A role in the research of perfusion evaluation of different types of esophageal reconstruction is suggested.

Effect of taurine on gastric ulcer in pylorus-ligated rats

AIM: To explore the effect of taurine on the pylorus ligation-induced gastric ulcer in rats and its mechanism.

METHODS: Rat model of gastric ulcer was made by pylorus ligation method. A total of 45 Wistar rats were randomly and averagely divided into 3 groups: normal control group, ulcer model group and taurine-treated group. Six hours later, all the rats were killed, and the gastric mucosal ulcer index (UI), total acidity of gastric juice, pepsin activity and H+,K+-ATPase activity in parietal cells were measured.

RESULTS: In comparison with the normal control group, the ulcer model group showed an increase in UI (35.3 ± 3.7 vs 0, P < 0.01), total acidity of gastric juice (28.56 ± 3.81 mmol/L vs 20.34 ± 4.40 mmol/L, P < 0.01), pepsin activity [7.58 ±1.58 μg/(mL·min) vs 5.83 ± 1.22 μg/(mL·min), P < 0.01] and H+, K+-ATPase activity of parietal cells (8.86 ± 1.50 U/mg vs 6.95 ± 1.03 U/mg, P < 0.01). However, in the treated group, the gastric mucosal injury was attenuated, and the value of gastric mucosal UI (15.4 ± 3.6 vs 35.3 ± 3.7, P < 0.01), total acidity of gastric juice (19.58 ± 3.68 mmol/L vs 28.56 ± 3.81 mmol/L, P < 0.01), pepsin activity [6.36 ± 1.45 μg/(mL·min) vs 7.58 ± 1.58 μg/(mL·min), P < 0.05] and H+, K+-ATPase activity of parietal cells (7.62 ± 1.46 U/mg vs 8.86 ± 1.50 U/mg, P < 0.05) were decreased significantly as compared with those in the model group.

CONCLUSION: Taurine can alleviate gastric ulcerative injury in pylorus-ligated rats, which may be related to the inhibitory effect of taurine on the secretion of gastric acid and pepsin.

Sphincter of Oddi function in the Australian brush-tailed possum is inhibited by intragastric ethanol

The role of sphincter of Oddi (SO) function in alcoholic acute pancreatitis (AP) is unclear. We aimed to compare the effect of i.v. and intragastric (IG) ethanol on SO function (i.e. trans-sphincteric flow; TSF) and investigate possible neural mechanisms. The involvement of gastric mucosal damage was also investigated by pretreatment with pantoprazole. In anaesthetized Australian possums, blood pressure (BP), TSF and blood ethanol concentrations were measured after i.v. or IG ethanol. Possums were subjected to acute vagotomy, atropine, L-nitro arginine methyl ester (L-NAME) or pantoprazole pretreatment prior to IG ethanol. BP was not significantly altered by ethanol. Ethanol decreased TSF in a dose and route-dependent manner. The lowest dose of IG ethanol reduced TSF but this response was not duplicated by i.v. ethanol producing the same blood ethanol concentrations. Acute vagotomy, atropine or L-NAME pretreatment blocked the ethanol-induced decrease in TSF and simultaneously suppressed the blood ethanol concentration. Pantoprazole pretreatment reduced the TSF response and blood ethanol concentrations implicating mechanisms induced by gastric mucosal damage. We conclude that ethanol (and/or its metabolites) reduces TSF via humoral and neural mechanisms involving vagal pathways, muscarinic receptors and nitric oxide. Reduced TSF could contribute to the onset of AP.

Effect of moxibustion at Zusanli and Liangmen point on gastric mucosal cell apoptosis in rats with stress ulcer

AIM: To explore the effects of moxibustion at Zusanli and Liangmen point on gastric mucosal cell apoptosis in rats with stress-induced ulcer, and analyze the relationship between those effects and the plasma content of dopamine (DA), mucosal expression of endothelin (ET).

METHODS: Sixty healthy Sprague Dawley rats were randomly assigned into 4 groups, named goup A, B, C and D, respectively. The animal model of stress ulcer was established by water immersion and restraint stress. The rats in group A, B, and D served as the restraint, model, and non-accupoint controls, while those in group C received moxibustion at Zusanli andLiangmen point. Immunohistochemical method was used to detect the apoptosis index (AI, ×10^-6/μm²) in all the groups, and biological signal analyzer was applied to measure gastric mucosal blood flow (GMBF). The plasma content of DA was examined by high efficiency liquid chromatography and the mucosal expression of ET was detected by radioimmunoassay.

RESULTS: Moxibustion at Zusanli and Liangmen point significantly decreased the gastric injury, plasma content of DA and mucosal expression of ET as well as the apoptosis of gastric mucosal cells, while markedly increased GMBF. In comparison with those in group A, the UI (26.80 ± 9.81 vs 12.00 ± 5.94, P < 0.01), plasma DA content (9.97 ± 3.69 μg/L vs 4.54 ± 2.61 μg/L, P < 0.01), mucosal ET expression (361.469 ± 98.080 ng/L vs 149.205 ± 94.1425 ng/L, P < 0.01) and AI (9.65 ± 4.19 vs4.36 ± 2.60, P < 0.01) were significantly increased, but GMBF (139.489 ± 33.133 mL/min vs 377.090 ± 85.840 mL/min, P < 0.01) was decreased in group B. However, the values of UI and AI were obviously lower in group C than those in group B and D (UI: 14.10 ± 5.42 vs 26.80 ± 9.81, 26.20 ± 7.23, P < 0.01; AI: 3.00 ± 1.58 vs 9.65 ± 4.19, 8.20 ± 5.17, P < 0.01), but GMBF was higher in group C (316.552 ± 85.469 mL/min vs 139.489 ± 33.133, 141.512 ± 58.450 mL/min, P < 0.01). the ulcer index (UI), the content of ET in gastric mucosa and DA in plasma decreased, GMBF increased, AI of gastric mucosa cells decreased (P < 0.05 or P < 0.01). Furthermore, the plasma DA and mucosal ET levels were significantly lower in group C than those in group B (DA: 4.41 ± 2.48 μg/L vs 9.97 ± 3.69 μg/L, P < 0.01; 148.271 ± 69.113 ng/L vs 361.469 ± 98.080 ng/L, P < 0.01), but they had no marked difference with those in group D.

CONCLUSION: Moxibustion at Zusanli and Liangmen point can resist the stress-induced injury, and the mechanism may be associated with the decrease of plasma DA level and gastric mucosal ET expression, improvement of GMBF and inhibition of gastric cell apoptosis.

Mucosal acid causes gastric mucosal microcirculatory disturbance in nonsteroidal anti-inflammatory drug-treated rats

The mechanism by which nonsteroidal anti-inflammatory drugs (NSAIDs) suppress gastric mucosal blood flow is not fully understood, although the depletion of mucosal prostaglandin E2 has been proposed as one possible explanation. We investigated the role of gastric acid on gastric mucosal blood flow in NSAID-treated rats. A rat stomach was mounted in an ex vivo chamber, and gastric mucosal blood flow was measured sequentially in a 5-mm2 area of the gastric corpus using a scanning laser Doppler perfusion image system. Results showed that diclofenac (5 mg/kg s.c.) and indomethacin (10 mg/kg s.c.) did not affect gastric mucosal blood flow, although both strongly decreased mucosal prostaglandin E2 when saline was instilled into the gastric chamber. On replacement of the saline in the chamber with 100 mM hydrochloric acid, these drugs caused a decrease in gastric mucosal blood flow levels within 30 min. The specific cyclooxygenase (COX)-2 inhibitors celecoxib (50 mg/kg s.c.) and rofecoxib (25 mg/kg s.c.) did not affect mucosal prostaglandin E2 level, nor did they decrease gastric mucosal blood flow, even when hydrochloric acid was added to the chamber. Furthermore, measurement of vasoconstrictive factors present in the mucosa showed that endothelin-1 levels increased after administration of diclofenac s.c. in the presence of intragastric hydrochloric acid. This indicates that the presence of mucosal hydrochloric acid plays an important role in the NSAID-induced decrease in gastric mucosal blood flow, while the COX-1-derived basal prostaglandin E2, which is unlikely to control gastric mucosal blood flow itself, protects microcirculatory systems from mucosal hydrochloric acid.

Endothelin-1, inducible nitric oxide synthase and macrophage inflammatory protein-1alpha in the pathogenesis of stress ulcer in neurotraumatic patients

BACKGROUND

To prospectively identify histologically and endoscopically the effect of omeprazole on the expression of endothelin-1 (ET-1), inducible nitric oxide synthase (iNOS) and macrophage inflammatory protein-1alpha (MIP-1alpha) in the gastric mucosa of neurosurgical patients with stress ulcer.

METHODS

Twenty-five patients with severe acute intracranial lesions caused by trauma were enrolled in this study. A 40 mg intravenous bolus of omeprazole (OME) was given daily for 7 days. The intragastric pH was continuously recorded for 24 hours on day 1 and 8. Endoscopic evaluation of the gastric corpus, antrum, and duodenal bulb was performed in the ICU, within 24 hours after brain injury, and at follow-up on the 7th day after admission. Paired biopsies were obtained for histologic examinations and immunohistochemical analysis was performed using a LSAB method for MIP-1alpha, ET-1, and iNOS.

RESULTS

There were 72% and 70% of gastroduodenal mucosal lesions at the initial and follow-up endoscopies, respectively. However, the severity of mucosal lesions showed significant improvement in most patients at follow-up (p < 0.05). Mean percentages of time intragastric pH were greater than or equal to 4.0 were 20 +/- 11% and 70 +/- 17% on day 1 and 8, respectively (p < 0.05). The incidences of ET-1, iNOS and MIP-1alpha expression were not significantly different between the patients before and after OME prophylaxis.

CONCLUSIONS

Prophylactic OME is effective in reducing the severity of stress ulcerations in severe neurotraumatic patients. High incidence of tissue ET-1 expression combined with increased activity of iNOS and MIP-1alpha may be responsible for the gastric mucosal injury. We also show that OME fails to counter the enhancement in the mucosal expression of ET-1, iNOS, and MIP-1alpha caused by severe brain damage.

Expression of HSP72 in the gastric mucosa is regulated by gastric acid in rats-correlation of HSP72 expression with mucosal protection

BACKGROUND AND AIM

The real mechanism of adaptive cytoprotection in the gastric mucosa is not well established. In the present study, we investigated the effect of acid suppressing agents on a 72-kDa heat shock protein (HSP72) expression, which is known as endogenous cytoprotective factor, in the gastric mucosa. Also, the association of gastric mucosal protective function against HCl-challenge was compared between HSP72-induced and -reduced group.

MATERIALS AND METHODS

Expression of HSP72 was measured by Western blotting in the gastric mucosa before and after administration of famotidine or omeprazole. The gastric mucosal protective function against 0.6 N HCl was compared between control group and HSP72-reduced group. Also, the effect of increased expression of gastric HSP72 by additional administration of zinc sulfate or zinc L-carnosine, which is known as HSP72-inducer, on mucosal protective function was studied.

RESULTS

HSP72 expression in the gastric mucosa was reduced by acid suppressing agents. The lowest expression level of HSP72 was observed 12 h (famotidine, H2-receptor antagonist) or 48 h (omeprazole, proton pump inhibitor) after administration. The gastric mucosal protective ability against 0.6 N HCl was also reduced when HSP72 expression was decreased by famotidine or omeprazole. This phenomenon was reversed by HSP72 induction by additional administration of zinc derivatives.

CONCLUSION

Our results might indicate that the expression of HSP72 in the gastric mucosa is physiologically regulated by gastric acid, and that HSP72 induction could be important in view of mucosal protection especially when HSP72 expression is reduced by administration of acid suppressing agents such as proton pump inhibitor or H2 receptor antagonist.

Methanandamide hyperpolarizes gastric arteries by stimulation of TRPV1 receptors on perivascular CGRP containing nerves

Endogenous as well as synthetic cannabinoids have potent vasodilatory actions in a variety of vascular preparations. Their precise mechanism of action is as yet unclear, but several studies point to the activation of type 1 vanilloid (TRPV1) receptors on primary afferent perivascular nerves, stimulating the release of calcitonin gene related peptide (CGRP). Given the documented gastroprotective function of these nerves, and the various gastrointestinal effects reported for cannabinoids, we explored a possible link between these systems in the gastric circulation by comparing responses of small gastric arteries to cannabinoids and to calcitonin gene related peptide using conventional microelectrode techniques. Exposure of small gastric arteries to the stable endocannabinoid analogue methanandamide caused a hyperpolarization of the vascular smooth muscle cells, which was completely abolished by the vanilloid receptor antagonist capsazepine (P < 0.01). Exposure to exogenous calcitonin gene related peptide evoked fully reproducible (P > 0.05) hyperpolarizations with similar time course, unaffected by capsazepine. Preincubation with glibenclamide, an inhibitor of ATP-sensitive potassium (KATP) channels, reversed both responses to methanandamide (P < 0.01) and calcitonin gene related peptide (P < 0.05). Similar results were found in rat mesenteric arteries. These findings show that cannabinoids stimulate TRPV1 receptors, presumably causing the release of calcitonin gene related peptide, which hyperpolarizes the smooth muscle cells by activation of KATP channels. Because membrane hyperpolarization is a powerful mediator of vasorelaxation, this novel pathway might prove to be an important mechanism affording gastroprotection.