The mechanisms of gastric mucosal injury: focus on microvascular endothelium as a key target

Lamivudine protects mice from gastric ulcer by activating PGK1 to suppress ferroptosis

Gastric ulcer is a highly prevalent digestive tract disease across the world, which is recurrent and hard to cure, sometimes transforming into gastric cancer if left untreated, posing great threat to human health. To develop new medicines for gastric ulcer, we ran a series of screens with ethanol stress model in GES-1 cells, and we uncovered that lamivudine rescued cells from ethanol toxicity. Then, we confirmed this discovery using the well-established ethanol-induced gastric ulcer model in mice and our findings suggest that lamivudine can directly activate phosphoglycerate kinase 1 (PGK1, EC 2.7.2.3), which binds and stimulates superoxide dismutase 1 (SOD1, EC 1.15.1.1) to inhibit ferroptosis and ultimately improve gastric ulcer. Moreover, AAV-PGK1 exhibited comparable gastroprotective effects to lamivudine. The findings are expected to offer novel therapeutic strategies for gastric ulcer, encompassing both lamivudine and AAV-PGK1.

Selenium Deficiency Causes Iron Death and Inflammatory Injury Through Oxidative Stress in the Mice Gastric Mucosa

Selenium (Se) is a trace element essential for the maintenance of normal physiological functions in living organisms. Oxidative stress is a state in which there is an imbalance between oxidative and antioxidant effects in the body. A deficiency of Se can make the body more inclined to oxidation, which can induce related diseases. The aim of this experimental study was to investigate the mechanisms by which Se deficiency affects the digestive system through oxidation. The results showed that Se deficiency treatment led to a decrease in the levels of GPX4 and antioxidant enzymes and an increase in the levels of ROS, MDA, and lipid peroxide (LPO) in the gastric mucosa. Oxidative stress was activated. Triple stimulation of ROS, Fe2+, and LPO induced iron death. The TLR4/NF-κB signaling pathway was activated, inducing an inflammatory response. The expression of the BCL family and caspase family genes was increased, leading to apoptotic cell death. Meanwhile, the RIP3/MLKL signaling pathway was activated, leading to cell necrosis. Taken together, Se deficiency can induce iron death through oxidative stress. Meanwhile, the production of large amounts of ROS activated the TLR4/NF-κB signaling pathway, leading to apoptosis and necrosis of the gastric mucosa.

Antiulcer activity and mechanism of action of the hydroethanolic extract of leaves of Terminalia argentea Mart. In different in vivo and in vitro experimental models

ETHNOPHARMACOLOGICAL RELEVANCE

Terminalia argentea Mart. (Combretaceae) is a deciduous tree commonly found in Brazil, Bolivia, and Paraguay. It occurs in all regions of Brazil and is widespread in the Amazon, Cerrado, Pantanal, Atlantic Rain Forest, and Caatinga Biomes. In the traditional medicine of Brazil, people widely use tea or decoction of its leaf materials for treating gastritis, ulcers, wound healing, and inflammation.

AIM OF THE STUDY

The current study aims to evaluate the gastroprotective and ulcer-healing activities of the hydroethanolic extract of T. argentea leaves (HETa) and investigate the underlying mechanisms of action through in vivo and in vitro experiments.

METHODS

We extracted the leaves of T. argentea with a 70% hydroethanolic solution (HETa) and performed phytochemical analysis using high-performance liquid chromatography (HPLC) and electrospray ionization mass spectrometry (ESI-MSn). We researched the antiulcer activity using in vivo and in vitro experiments, administering three doses (2, 10, and 50 mg/kg) and different concentrations of 1, 5, and 20 μg/mL, respectively. We verified the acute antiulcer activity using chemical models (acidified ethanol (EtOH/HCl) and indomethacin (IND)) and physiological models (water-immersion stress (WRS)). To induce chronic ulcers, used acetic acid and treated the animals for seven days. To investigate the mechanism of action, conducted assays of antioxidant activity, measured the dosage of inflammatory cytokines, quantified mucus, treated with inhibitors (IND, L-NAME, glibenclamide, and yohimbine), performed histopathological analysis, and measured gastric acid secretion. Furthermore, we performed in vitro experiments on murine macrophage cell lines (RAW 264-7 cells) to quantify nitrite/nitrate and cytokine production and on V79-4 cells to verify cell proliferation/migration.

RESULTS

We conducted HPLC and ESI-MSn analyses to obtain a fingerprint of the chemical composition of the HETa, revealing the presence of phenolics (caffeoyl ellagic acid), flavonoids (rutin, quercetin xyloside, quercetin rhamnoside, quercetin glucoside, quercetin galloyl xyloside, quercetin), and tannins (terminalin), respectively. The three doses of HETa reduced acute and chronic ulcers in different models. The mechanism of action involves increasing mucus production and angiogenesis, and it partially involves prostaglandins, nitric oxide, K+ATP channels, and α2-adrenergic receptors. HETa also exhibited antioxidant potential, reducing myeloperoxidase (MPO) activity, and increasing glutathione (GSH) levels. Moreover, it demonstrated anti-inflammatory action by reducing nitrite/nitrate levels and pro-inflammatory cytokine concentrations in vivo, and it increased in vitro proliferation/migration of fibroblasts.

CONCLUSIONS

The study shows that HETa presents a potent preventive and curative antiulcer effect in different ulcer models, supporting the popular use of homemade preparations of T. argentea leaves. The preventive and gastric healing ulcer activity of HETa involves multiple targets, including increasing the gastric mucus barrier, antioxidant defenses, and anti-inflammatory effects on gastric mucosa repair. Phytochemical analysis identified the presence of phenolic compounds, flavonoids, and tannins in HETa, and the antiulcer activity may be attributable to the combined effect of these constituents.

Oxidative Coupling Assembly Induced Bio-engineered Quercetin Microspheres for the Gastrosparing Delivery of Diclofenac Sodium

OBJECTIVE

The study aimed to develop microspheres of quercetin by oxidative coupling assembly and these microspheres were used to deliver diclofenac sodium without causing gastrotoxicity.

METHODS

The oxidative coupling assembly of quercetin was carried out in the presence of copper sulfate to yield quercetin microspheres. The microsphere of quercetin was loaded with diclofenac sodium (QP-Diclo). The carrageenan induced paw edema in rats was used for anti-inflammatory action was studied by using and acetic acid-induced writhing in mice was used to study the analgesic potential of the QP loaded microspheres. The ulcerogenecity and gastrotoxicity comparison was made between diclofenac and QP-Diclo.

RESULTS

The oxidative coupling assembly of quercetin resulted in microspheres of 10-20 μm in size, which were loaded with diclofenac sodium (QP-Diclo). The marked anti-inflammatory activity was observed by QP-Diclo treatment using carrageenan induced paw edema (in rats) and better analgesic activity than diclofenac sodium in mice. The administration of QP-Diclo significantly elevated the diminished overall nitrite/nitrate extent and thiobarbituric acid reactive and significantly increased the diminished superoxide dismutase activity in comparison to diclofenac sodium in gastric mucosa.

CONCLUSION

The results suggested that dietary polyphenol quercetin can be converted to microspheres by oxidative coupling assembly and can be used to deliver diclofenac sodium without causing gastrotoxicity.

Gastric protective effect of Alpinia officinarum flavonoids: mediating TLR4/NF-κB and TRPV1 signalling pathways and gastric mucosal healing

CONTEXT

Our previous studies have found that total flavonoid of Alpinia officinarum Hance (Zingiberaceae) (F.AOH) had protective effects on gastric ulcer (GU).

OBJECTIVE

To investigate the protective mechanism of F.AOH on acetic acid-induced chronic GUs in rats and ethanol-induced GES-1 cells damage.

MATERIALS AND METHODS

In vivo: Gastric damage was induced in SD rats by administering acetic acid after oral treatment with F-AOH at 54, 27 and 13.5 mg/kg (2 weeks of continuous gavage). After a comprehensive evaluation of rats' serum and gastric tissue-related indicators, gene transcriptome sequencing, qPCR and Western blotting were used to investigate the mechanism further. In vivo: GES-1 cells were incubated with F-AOH (8, 4 and 2 μg/mL) for 16 h and treated with 7% ethanol for 4 h. Transwell and flow cytometry were employed to detect migration and apoptosis of cells.

RESULTS

F.AOH effectively reduced the area of GUs in rats (from 11.2 ± 1.89 to 2.19 ± 0.95), reversing ethanol-induced cells apoptosis (from 23 ± 1.3 to 8.11 ± 0.93%). It also inhibited the expression of endothelin-1 (ET-1) and iNOS proteins, decreasing the levels of TNF-α IL-6 in serum, improving oxidative stress levels and increasing the expression of Bcl-2/Bax dimer genes. In addition, 4005 differentially expressed genes between the acetic acid model and the drug groups. Through experimental verification, F.AOH can inhibit the activation of TLR4/NF-κB signalling pathway and TRPV1 receptor.

CONCLUSIONS

F.AOH, as an effective gastric protective plant component, had potential therapeutic value in anti-inflammatory pain and antioxidative stress gastrointestinal diseases.

Antiulcer mechanisms of the hydroalcoholic extract from Aztec marigolds' medicinal and edible flowers (Tagetes erecta L.)

The antiulcer mechanisms of the dry extract of T. erecta flowers (DETe) were studied here. The acute ulcers induced by acidified ethanol or indomethacin were reproduced in mice pretreated with DETe (3 - 300 mg/kg). The antiulcer activity of DETe was also verified in mice pretreated with NEM, L-NAME, indomethacin, or yohimbine. The antisecretory effect of DETe was verified in rats, and its anti-Helicobacter pylori activity was determined in vitro. DETe (300 mg/kg, p.o) reduced the ethanol- or indomethacin-induced ulcer by 49 and 93%, respectively. The pre-treatment with L-NAME, NEM or yohimbine abolished the gastroprotective effect of DETe. However, DETe did not change the volume, acidity, or peptic activity in rats and did not affect H. pylori. This study expands knowledge about the antiulcerogenic potential of DETe, evidencing the role of nitric oxide, non-protein sulfhydryl groups, α2 adrenergic receptors, and prostaglandins, but not antisecretory or anti-H. pylori properties.

Dendrobium huoshanense stem polysaccharide ameliorates alcohol-induced gastric ulcer in rats through Nrf2-mediated strengthening of gastric mucosal barrier

This study aimed to explore whether Dendrobium huoshanense stem polysaccharide (cDHPS) ameliorates alcohol-induced gastric ulcer (GU) through the strengthening effect of the gastric mucosal barrier in rats and its potential mechanism. In normal rats, the pretreatment of cDHPS effectively strengthened gastric mucosal barrier by increasing mucus secretion and tight junction protein expression. In GU rats, cDHPS supplementation effectively alleviated alcohol-induced gastric mucosal injury and nuclear factor κB (NF-κB)-driven inflammation by strengthening gastric mucosal barrier. Moreover, cDHPS significantly activated nuclear factor E2-related factor 2 (Nrf2) signaling and promoted antioxidant enzymes activities in both normal and GU rats. These results suggested that the pretreatment of cDHPS could strengthen gastric mucosal barrier to inhibit oxidative stress and NF-κB-driven inflammation induced gastric mucosal injury, which was likely related to the activation of Nrf2 signaling.

Gastroprotective effect of dapagliflozin in ethanol-induced gastric lesions in rats: Crosstalk between HMGB1/RAGE/PTX3 and TLR4/MyD88/VEGF/PDGF signaling pathways

Alcohol abuse may lead to the development of gastric mucosal lesions. Dapagliflozin (DAPA), a sodium-glucose cotransporter-2 inhibitor, is clinically used to treat type 2 diabetes mellitus. However, studies showed protective effect of DAPA under various experimental conditions by alleviating oxidative stress and inflammation. The effect of DAPA on experimental gastric ulcer has not been studied yet. Therefore, we attempted to investigate DAPA's protective effect against ethanol (EtOH)-induced gastric lesions. Fifty-six (8-week-old) male Wistar rats were divided into seven groups. DAPA (1, 5, and 10 mg/kg/day; p.o.) was given for seven days, plus a single dose of absolute EtOH (5 ml/kg) on day 8. According to hematoxylin and eosin, and Alcian blue staining of gastric tissue sections, titratable acidity, and macroscopic assessments, DAPA high dose (10 mg/kg) was the most protective, with lesser ulcerations, and higher mucin, relative to the lower two doses and the standard treatment omeprazole (OME). In rats pre-treated with DAPA high dose, colorimetric and ELISA analyses revealed significantly decreased oxidative stress, pro-inflammatory, and apoptosis indices and increased levels of platelet-derived growth factor (PDGF) and vascular endothelial growth factor (VEGF). Western blot analysis revealed reduced pentraxin-3 (PTX3), high-mobility group box 1 (HMGB1), receptor for advanced glycation end products (RAGE), toll-like receptor 4 (TLR4), and myeloid differentiation factor 88 (MyD88) expression. These results were comparable in DAPA (10 mg/kg) and OME pre-treated groups. Overall, DAPA exerted a dose-dependent protective effect against EtOH-induced gastric injury. Gastroprotective effects of DAPA (10 mg/kg) may be associated with influencing HMGB1/RAGE/PTX3 and TLR4/MyD88/VEGF/PDGF pathways.

Gastroprotective and gastric healing effects of the aqueous extract of Casearia sylvestris in rodents: Ultrasound, histological and biochemical analyzes

ETHNOPHARMACOLOGICAL IMPORTANCE

Casearia sylvestris Sw. (Salicaceae) is a native plant from the Americas, where it is also known as "guaçatonga" or "erva-de-bugre." Although its leaves have been commonly used to treat inflammation and gastrointestinal disorders in South America, the antiulcer effects of an aqueous extract from this medicinal plant, similar to popular use, have not to be investigated yet.

AIM OF THE STUDY

This study evaluated the hypothesis that the aqueous extract a of C. sylvestris (AEC) prevents the gastric ulcers and accelerates the healing of ulcers already installed, by assessing ultrasound imaging, histological and biochemical analyses.

MATERIALS AND METHODS

Rats (females) were treated with AEC (3, 30 or 300 mg/kg) prior to the ethanol or piroxicam-induced gastric ulcers. The healing effect of AEC (300 mg/kg) was examined in 80% acetic acid-induced ulcer in rats, whereas the quality of healing was evaluated in recurrent 10% acetic acid-induced ulcer in mice with recurrence induced by interleukin 1β. To assess the responses of the lesions, in addition to the classical methods used to analyze gastroprotection (ex vivo), we also measured the gastric wall thickness (in vivo) using ultrasonography. After euthanasia, the extent of ulcer was determined and the levels of reduced glutathione (GSH), lipid hydroperoxides (LOOH), nitrate, and the activities of myeloperoxidase (MPO), N-acetyl-β-D-glycosaminidase (NAG), superoxide dismutase (SOD), and glutathione S-transferase (GST) were measured. The antisecretory activity of AEC was also examined based on pylorus ligated rats. Furthermore, gastric tissue samples were analyzed histologically, and phytochemical analyses of the C. sylvestris extract were parallelly performed.

RESULTS

The AEC (30 or 300 mg/kg) prevented ulcers in the ethanol- and piroxicam-induced acute. Moreover, the AEC at a dose of 300 mg/kg also accelerated the gastric healing of acetic acid-induced ulcer in rats by 48% and the ultrasonography records shown a decrease in the wall thickness and the extent of edema of ulcerous lesions promoted by the extract. The gastric healing effect of AEC was also accompanied by reduced MPO and NAG activities at acetic acid-induced ulcer in rats; as well as was by the reduction in the nitrate and LOOH levels, the increase in mucin and SOD activity, and by a partial recovery of GSH levels. The AEC (300 mg/kg) minimized the ulcer recurrence in mice exposed to IL-1β, but the extract administration did not change pH or peptic activity of gastric juice in pylorus ligated rats.

CONCLUSION

The results of this study provide convincing evidence for the therapeutic efficacy of C. sylvestris with respect to gastroprotection and indicate that ultrasound examination would be a potentially promising approach for evaluating gastroprotective effects in vivo. Collectively, our findings indicate that the gastric the gastroprotective and healing effects of aqueous extract C. sylvestris involve a reduction in acid secretion, promotion of the antioxidant system, reductions in the migration of neutrophils and mast cells, with a consequent lower inflammatory response, and the preservation of mucin.

Petechial hemorrhages, ethanol, and opioids in victims from intoxication

Petechial hemorrhages are of interest to forensic pathologists because of their association with pressure on the neck. This study shows the associations between ethanol, opioids in blood and the risk of petechiae in conjunctivae and eye lids of 865 medico-legally examined victims from intoxication, 112 (12.9 %) with petechiae. Livor mortis on the front, face down body position, higher body weight, and younger age of the victims were independently associated with higher risk of petechiae. These variables were used for adjustment in the logistic regression analyzes. We found associations between ethanol, opioids, and the risk of petechiae when analyzed simultaneously. The association between ethanol and the risk of petechiae differed in opioid negative and positive victims (interaction, p = 0.028). In the opioid negative group, the association was J-formed, victims with low to medium level ethanol having lower risk (OR = 0.77) than those without ethanol or opioids, whereas high ethanol level gave a 4-fold higher risk (OR = 3.97). In the opioid positive group, the J-formed pattern was reversed. Victims with low to medium level ethanol had more than 4 times higher risk (OR = 4.65), whereas high level ethanol gave a slightly elevated risk (OR = 1.34) only compared to no ethanol or opioids. The results suggest that ethanol and opioids have a complex association with the risk of petechiae independent of livor mortis, initial body position, body weight, and age in victims from intoxication. Of practical value for the post-mortem examination is that the pathologist must consider both the ethanol level and the presence of opioids when judging the significance of petechiae in the eye regions.

Alloimperatorin from Ammi majus fruits mitigates Piroxicam-provoked gastric ulcer and hepatorenal toxicity in rats via suppressing oxidative stress and apoptosis

Introduction: Fruits of Ammi majus, commonly called bishop's weed, contain a significant amount of furanocoumarins. Alloimperatorin (Allo, 6) was isolated from the free coumarin fraction of fruits, beside 8-hydroxypsoralen (1), methoxsalen (2), heraclin (3), isoimperatorin (4), imperatorin (5), isoheraclenin (7) and heraclenin hydrate (8). Piroxicam (Px) is a widely used pain-relieving drug that demonstrated side effects, including gastric ulceration and hepatorenal toxicity.Objective: This study aimed to investigate the protective potential of Alloimperatorin against Px-induced gastric ulceration and hepatorenal toxicity.Material & Methods: Rats were divided into four groups: Negative control, Px-induced rats, Allo + Px co-treated group, and Pc + Px co-treated group. Allo (25 mg/kg body weight) and Pc (25 mg/kg body weight) treatments were received 5 days before and 4 days after Px intoxication for 4 days (50 mg/kg body weight). Serum prostaglandin E2 (PG-E2) and liver and kidney functions were measured. Oxidative stress markers were evaluated in the three tissues. Histopathological features and caspase-3 immunoexpression were monitoredResults & Discussion: Px triggered gastric ulceration, increased indices of liver and kidney functions, decreased PG-E2 levels, provoked oxidative stress, and activated caspase-3 immunoexpression. Co-treatment with Allo demonstrated protective activities.Conclusion: Alloimperatorin exhibited anti-oxidative, anti-inflammatory, and anti-apoptotic activities.

Microvascular reactivity as a predictor of major adverse events in patients with on-pump cardiac surgery

Background

Microcirculatory disturbances are typically most severe during cardiopulmonary bypass (CPB), which occurs during cardiac surgeries. If microvascular reactivity compensates for microcirculatory disturbances during CPB, tissue hypoxemia can be minimized. The primary aim of this study was to assess whether microvascular reactivity during CPB could predict major adverse events (MAE) after cardiac surgery.

Methods

This prospective observational study included 115 patients who underwent elective on-pump cardiac surgeries. A vascular occlusion test (VOT) with near-infrared spectroscopy was performed five times for each patient: before the induction of general anesthesia, 30 min after the induction of general anesthesia, 30 min after applying CPB, 10 min after protamine injection, and post-sternal closure. The postoperative MAE was recorded. The area under the receiver operating characteristic (AUROC) curve analysis was performed for the prediction of MAE using the recovery slope.

Results

Of the 109 patients, MAE occurred in 32 (29.4%). The AUROC curve for the recovery slope during CPB was 0.701 (P < 0.001; 95% CI [0.606, 0.785]). If the recovery slope during CPB was < 1.08%/s, MAE were predicted with a sensitivity of 62.5% and specificity of 72.7%.

Conclusions

Our study demonstrated that the recovery slope of the VOT during CPB could predict MAE after cardiac surgery. These results support the idea that disturbances in microcirculation induced by CPB can predict the development of poor clinical outcomes, thereby demonstrating the potential role of microvascular reactivity as an early predictor of MAE after cardiac surgery.

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.

Responses of increasingly complex intestinal epithelium in vitro models to bacterial toll-like receptor agonists

The intestine fulfills roles in the uptake of nutrients and water regulation and acts as a gatekeeper for the intestinal microbiome. For the latter, the intestinal gut barrier system is able to respond to a broad range of bacterial antigens, generally through Toll-like receptor (TLR) signaling pathways. To test the capacity of various in vitro intestinal models, we studied IL-8 secretion, as a marker of pro-inflammatory response through the TLR pathway, in a Caco-2 monoculture, Caco-2/HT29-MTX di-culture, Caco-2/HT29-MTX/HMVEC-d tri-culture and in a HT29-p monoculture in response to exposure to various TLR agonists. Twenty-one-day-old differentiated cells in Transwells were exposed to Pam3CSK4 (TLR1/2), lipopolysaccharide (TLR4), single-stranded RNA (TLR7/8), Poly(i:C) (TLR3) and flagellin (TLR5) for 24 h. In all systems IL-8 secretion was increased in response to flagellin exposure, with HT29-p cells also responding to Poly(I:C) exposure. All other agonists did not induce an IL-8 response in the tested in vitro models, indicating that the specific TLRs are either not present or not functional in these models. This highlights the need for careful selection of in vitro models when studying intestinal immune responses and the need for improved in vitro models that better recapitulate intestinal immune responses.

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.

Effects of nitro-butoxyl- and butyl-esters of non-steroidal anti-inflammatory drugs compared with parent compounds on the contractility of digital arterial smooth muscle from the fallow deer (Dama dama)

BACKGROUND

Non-steroidal anti-inflammatory drugs (NSAIDs) are a major cause of upper gastro-intestinal (GI) ulceration and bleeding as well as cardiovascular (CV) diseases (e.g., myocardial infarction and stroke). A feature common to both these adverse events is a variety of vascular reactions. One approach to overcome these side effects has been the development of nitric-oxide (NO)-donating NSAIDs. The NO is considered to overcome some of these vascular reactions caused by NSAIDs. Unfortunately, the NO-NSAIDs developed so far have not had the expected benefits compared with NSAIDs alone.

OBJECTIVES

Using in vitro preparations it is hoped to gain insight into the vascular and smooth muscle reactions induced by NO-NSAIDs compared with NSAIDs as a basis for improving the protective responses attributed to the NO-donating properties of these drugs.

METHODS

A range of NO-NSAIDs was synthesized based on the esterification of NSAIDs with the nitro-butoxylate as a prototype of an NO-donor. These compounds, as well as NO-donor agents and NSAIDS, were examined for their possible effects on isolated segments of digital arteries of fallow deer, which provide a robust model for determining the effects of vasodilator and vasoconstrictor activities, in comparison with those of standard pharmacological agents.

RESULTS

The NO-NSAIDs were found to antagonise the smooth muscle contractions produced by 5-hydroxytryptamine (serotonin, 5-HT). However, while almost all their parent NSAIDs had little or no effect, with the exception of the R-(-)-isomers of both ibuprofen and flurbiprofen, which caused vasodilatation, all the NO-NSAIDs tested antagonised the increase in tension produced by 5-HT.

CONCLUSIONS

R-(-)-ibuprofen and R-(-)-flurbiprofen, along with the nitro-butoxyl esters of the NSAIDs examined, produce relaxation of segments of deer digital artery smooth muscle in vitro. The evidence presented suggests that their mechanism involves the release of NO or its products.

Interference of LPS H. pylori with IL-33-Driven Regeneration of Caviae porcellus Primary Gastric Epithelial Cells and Fibroblasts

Background: Lipopolysaccharide (LPS) of Helicobacter pylori (Hp) bacteria causes disintegration of gastric tissue cells in vitro. It has been suggested that interleukin (IL)-33 is involved in healing gastric injury. Aim: To elucidate whether Hp LPS affects regeneration of gastric barrier initiated by IL-33. Methods: Primary gastric epithelial cells or fibroblasts from Caviae porcellus were transfected with siRNA IL-33. Such cells, not exposed or treated with LPS Hp, were sub-cultured in the medium with or without exogenous IL-33. Then cell migration was assessed in conjunction with oxidative stress and apoptosis, activation of extracellular signal-regulated kinase (Erk), production of collagen I and soluble ST2 (IL-33 decoy). Results: Control cells not treated with LPS Hp migrated in the presence of IL-33. The pro-regenerative activity of IL-33 was related to stimulation of cells to collagen I production. Wound healing by cells exposed to LPS Hp was inhibited even in the presence of IL-33. This could be due to increased oxidative stress and apoptosis in conjunction with Erk activation, sST2 elevation and modulation of collagen I production. Conclusions: The recovery of gastric barrier cells during Hp infection potentially can be affected due to downregulation of pro-regenerative activity of IL-33 by LPS Hp.

Seasonal variation of peptic ulcer disease, peptic ulcer bleeding, and acute pancreatitis: A nationwide population-based study using a common data model

Although gastrointestinal diseases are reported at various times throughout the year, some particular seasons are associated with a higher incidence of these diseases. This study aimed to identify the seasonal variations of peptic ulcer (PU), peptic ulcer bleeding (PUB), and acute pancreatitis (AP) in South Korea.We conducted a retrospective, observational cohort study of all subjects aged >18 years between 2012 and 2016 using the Health Insurance Review and Assessment-National Patient Samples database, previously converted to the standardized Observational Medical Outcomes Partnership-Common Data Model. We assessed the overall seasonal variations of PU, PUB, and AP and further analyzed seasonal variations according to age and sex subgroups.In total, 14,626 patients with PU, 3575 with PUB, and 9023 with AP were analyzed for 5 years. A clear seasonal variation was noted in PU, with the highest incidence rate during winter, the second highest during spring, the third highest during summer, and the lowest incidence during autumn for 5 years (P < .001). PUB also showed significant seasonal fluctuations, with winter peak for 4 years, except 1 year, which had a spring peak (P < .001). However, AP showed no clear seasonal variations (P = .090). No significant differences in the seasonal variation of PU, PUB, and AP were observed according to sex and age subgroups (<60 years vs ≥60 years).Seasonal variation of PU and PUB should be considered when determining allocation of available health care resources.

Sphaeranthus senegalensis DC: Evaluation of chemical constituents, oral safety, gastroprotective activity, and mechanism of action of its hydroethanolic extract

ETHNOPHARMACOLOGICAL RELEVANCE

Sphaeranthus senegalensis DC is a seasonal herb with a spicy smell that grows wild in wet grounds of tropical Africa and Asia. The plant is used in folk medicine for the treatment of various diseases; that includes its use to treat gastric ulcers.

AIM OF THE STUDY

This study aimed to investigate the chemical constituents of the hydroethanolic extract of Sphaeranthus senegalensis DC and evaluate its oral safety, gastroprotective activity, and mechanisms of action using laboratory models in rats and mice.

MATERIALS AND METHODS

Hydroethanolic extract (70%) of the powdered whole dried material was prepared, and chemical constituents of the resultant extract (denoted HESs) standardized using the high-performance liquid chromatography (HPLC) method. The safety profile of HESs was assessed using 2000 mg/kg, oral (p.o.) for Hippocratic screening in mice, and 800 mg/kg, p.o. for 28 days subchronic toxicity assay in rats. The gastroprotective effect of HESs (25, 100, and 400 mg/kg, p.o.) was investigated using acidified ethanol, piroxicam, water immobilization stress, and acetic acid-induced ulcer models. The gastroprotective mechanisms of HESs were evaluated using its effect on gastric mucus protection, nitric oxide modulation, gastric juice secretory parameters, catalase and myeloperoxidase activities. Histological analysis of the stomach tissues was also carried out.

RESULTS

The HPLC analysis indicated the presence of 25.94% phenolics (gallic acid, caffeic acid, and ferulic acid) and 14.53% flavonoids (rutin, morin, luteolin, quercetin, and apigenin). Hippocratic screening and the 28 days subchronic study indicated that HESs is generally safe. Result shows that oral administration of HESs (25, 100 and 400 mg/kg) alleviated the severity of the gastric ulcers induced by acidified ethanol by 35.65% (p < 0.05), 48.70% (p < 0.05) and 78.02% (p < 0.001) respectively; exhibited gastroprotective effect against the gastric lesions induced by piroxicam by 37.97% (p < 0.05), 53.27% (p < 0.05) and 76.23% (p < 0.001) respectively; and decreased the severity of the water immobilization stress-induced gastric ulcers by 32.43% (p < 0.05), 55.26% (p < 0.01) and 74.05% (p < 0.001) respectively, when compared to the vehicle control group. The mechanisms of action assays indicated that the gastroprotective activity was mediated mainly through gastroprotection, antisecretory, and antioxidant activities. Histological analysis showed it inhibited epithelial cell loss, vascular damage, and leucocyte infiltration.

CONCLUSION

HESs contains useful phytochemicals, is safe, and exhibited significant gastroprotective action. The results provided justification for its claim in the treatment of gastric ulcers and its evaluation for potential application as a gastroprotective agent.

Combination of Panax notoginseng saponins and aspirin potentiates platelet inhibition with alleviated gastric injury via modulating arachidonic acid metabolism

High platelet reactivity and gastric mucosal injury after aspirin (ASA) treatment are associated with poor compliance and an increased risk of cardiovascular events. Panax notoginseng saponins (PNS) have been widely used for the treatment of coronary heart disease (CHD) in addition to antiplatelet drugs in China; however, the joint effect and possible mechanism of PNS in addition to ASA on platelet activation and gastric injury remain unclear. This study was designed to investigate the combinational effects of PNS with ASA, and to explore the underlying mechanism via arachidonic acid (AA) metabolism pathway using lipidomic analysis. In a randomized, assessor-blinded trial, 42 patients with stable coronary heart disease (SCHD) and chronic gastritis were randomly assigned to receive ASA (n = 21) or PNS + ASA (n = 21) for 2 months. Compared with ASA alone, PNS + ASA further inhibited CD62p expression, GPIIb-IIIa activation and platelet aggregation and led to increased platelet inhibition rate. PNS + ASA suppressed the activity of platelet cyclooxygenase (COX)-1, and decreased the production of TXB2, PGD2, PGE2, 11-HETE, the downstream oxylipids of AA/COX-1 pathway in platelets, compared with ASA alone. The severity of dyspepsia assessment (SODA) results showed that patients in PNS + ASA group exhibited relieved dyspeptic symptoms as compared with those in ASA group, which might be associated with enhanced secretion of gastrin and motilin. In vivo study of myocardial infarction rats demonstrated that PNS attenuated ASA-induced gastric mucosal injury, which was related to markedly boosted gastric level of 6,15-diketo-13,14-dihydro-prostaglandin (PG)F1α, 13,14-dihydro-15-keto-PGE2 and PGE2 from AA/PG pathway in response to PNS + ASA compared with ASA alone. In summary, our study demonstrated that the combination of PNS and ASA potentiated the antiplatelet effect of ASA via AA/COX-1/TXB2 pathway in platelets, and mitigated ASA-related gastric injury via AA/PG pathway in gastric mucosa.

Protective Effects of Wheat Peptides against Ethanol-Induced Gastric Mucosal Lesions in Rats: Vasodilation and Anti-Inflammation

Alcohol consumption increases the risk of gastritis and gastric ulcer. Nutritional alternatives are considered for relieving the progression of gastric mucosal lesions instead of conventional drugs that produce side effects. This study was designed to evaluate the gastroprotective effects and investigate the defensive mechanisms of wheat peptides against ethanol-induced acute gastric mucosal injury in rats. Sixty male Sprague-Dawley rats were divided into six groups and orally treated with wheat peptides (0.1, 0.2, 0.4 g/kgbw) and omeprazole (20 mg/kgbw) for 4 weeks, following absolute ethanol administration for 1 h. Pretreatment with wheat peptides obviously enhanced the vasodilation of gastric mucosal blood vessels via improving the gastric mucosal blood flow and elevating the defensive factors nitric oxide (NO) and prostaglandin E2 (PGE2), and lowering the level of vasoconstrictor factor endothelin (ET)-1. Wheat peptides exhibited anti-inflammatory reaction through decreasing inducible nitric oxide synthase (iNOS) and pro-inflammatory cytokines tumor necrosis factor α (TNF-α), interleukin (IL)-1β, IL-6, and increasing trefoil factor 1 (TFF1) levels. Moreover, wheat peptides significantly down-regulated the expression of phosphorylated nuclear factor kappa-B (p-NF-κB) p65 proteins in the NF-κB signaling pathway. Altogether, wheat peptides protect gastric mucosa from ethanol-induced lesions in rats via improving the gastric microcirculation and inhibiting inflammation mediated by the NF-κB signaling transduction pathway.

The Therapeutic Effect of Nigella sativa Seed on Indomethacin-induced Gastric Ulcer in Rats

Background:

Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used to relieve pain and reduce inflammation. However, gastric complications remain a major problem limiting their clinical usage. This study was carried out to evaluate the therapeutic effect of Nigella sativa seed (N. sativa seed) hydroalcoholic extract on indomethacin-induced gastric ulcer in rats and its possible mechanism.

Methods:

This study was carried out on forty-eight male Wistar rats. Gastric ulcer was induced by indomethacin (35 mg/kg). N. sativa seed extract (100, 200, and 400 mg/kg) and ranitidine (50 mg/kg) was administered orally for five days after ulcer induction. Ulcer index, gastric acid secretion, gastric mucus content, total thiol, malondialdehyde (MDA), and total hexose, and protein content in gastric juice were determined.

Results:

The ulcer index in groups of N. sativa seed was significantly lower as compared to indomethacin group. N. sativa seed significantly decreased MDA and protein content, but increased total thiol, total hexose, and mucus content as compared to indomethacin group. N. sativa seed did not affect gastric acid secretion.

Conclusion:

These findings showed that the gastroprotective effect of N. sativa seed against indomethacin- induced ulcer was mainly exerted by antioxidant activity, stimulation of gastric mucus secretion and also increased total hexose in the gastric mucosa.

Proregenerative Activity of IL-33 in Gastric Tissue Cells Undergoing Helicobacter Pylori-Induced Apoptosis

Interleukin (IL)-33 is a proinflammatory mediator that alerts the host immune system to disorders in tissue homeostasis. Aim. To understand the role of IL-33 in modulating gastric tissue cell growth affected by Helicobacter pylori (H. pylori). Methods. IL-33 production in guinea pigs (Caviae porcellus) experimentally infected with H. pylori was evaluated by ELISA or immunohistochemical staining. The proregenerative activity of IL-33 was evaluated using gastric epithelial cells and fibroblasts that were naive or transfected with IL-33 siRNA exposed to H. pylori glycine acid extract antigenic complex (GE), as well as by measuring cell migration, proliferation, metabolic activity and apoptosis. Animals infected by H. pylori responded with increased production of IL-33. Also, cells treated in vitro with GE released more IL-33 than cells that were unstimulated. Silencing IL-33 in cells resulted in downregulation of metabolic activity, adhesion, migration and proliferation, especially after treatment with H. pylori GE, as well as upregulation of cells apoptosis associated with caspase 3 increase and Bcl-xL decrease, suggesting proregenerative activity of IL-33. Interestingly, upregulation of cell proliferation by IL-33 was Erk independent. Our results indicate that IL-33 may protect gastric tissue from loss of homeostasis caused by deleterious effects of H. pylori components and the inflammatory response developed during infection.

The preventive effect of Nigella sativa seed on gastric ulcer induced by indomethacin in rat

Introduction: Nonsteroidal anti-inflammatory drugs (NSAIDs) are considered as one of the most administrated groups of medications worldwide. Due to the role of NSAIDs in inducing gastric ulceration, their clinical applications are still challenging. Nigella sativa seed is widely used as an herbal medication against gastrointestinal complications. The present experiment was carried out to investigate the impact of N. sativa seed hydro-alcoholic extract on gastric ulcer induced by indomethacin (IND) and to evaluate its possible mechanisms in rat. Methods: This study was performed on 48 male Wistar rats. Acute gastric ulceration was induced by IND (35 mg/kg). N. sativa seed extract (100, 200, 400 mg/kg) and ranitidine (50 mg/kg) were administered orally for five days before the induction ulcer. Ulcer index, gastric acid secretion, gastric mucus content, glutathione (GSH), malondialdehyde (MDA), total hexose, gastric juice protein content were determined on the fifth day. Results: The ulcer index in all groups of N. sativa seed was significantly lower than that of the IND group. N sativa seed considerably decreased MDA and protein content, but increased total thiol, total hexose, and mucus content compared to the IND group. N. sativa seed did not affect gastric acid secretion. Conclusion: These findings were indicative of the gastroprotective effect of N. sativa seed against the IND-induced ulcer, suggesting that it can mainly be exerted through the anti-oxidant activity of the extract as well as its role in stimulating gastric mucus secretion and increasing total hexose in the gastric mucosa.

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.

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.

Protective effect of Pu-erh tea extracts against ethanol-induced gastric mucosal damage in rats

Pu-erh tea has become a focus of research due to its reported biological activities, including anti-oxidation, anti-inflammation and anti-immunosenescence. The present study was performed to evaluate the potential gastroprotective function of Pu-erh tea extracts against ethanol-induced gastric mucosal damage in rats. Sprague Dawley rats were randomly divided into seven groups: A normal control, a model control, a cimetidine (0.08 g/kg) group, three Pu-erh tea extracts groups (low, moderate and high-dose; 0.50, 1.00 and 1.50 g/kg, respectively, and a green tea powder (1.00 g/kg) group. The normal and model groups were pre-treated with distilled water while the other groups were respectively administered cimetidine, Pu-erh tea extracts and green tea powder for 14 days. Then, absolute ethanol was orally administered to the rats of all groups excluding the normal controls. The effects of the pretreatments on gastric mucosal injury were evaluated by gross assessment of gastric lesions, examination of histopathology and determination of myeloperoxidase (MPO) activity and asymmetric arginine (ADMA) concentration in gastric mucosal homogenate. Pre-treatment with cimetidine or Pu-erh tea extracts markedly suppressed the formation of ethanol-induced gastric lesions. Furthermore, clear decreases in MPO activity and ADMA concentration in the gastric mucosal homogenate were observed following pretreatment with cimetidine or Pu-erh tea extracts. The anti-gastric ulcer activity of green tea was less than that of Pu-erh tea. Overall, these effects of Pu-erh tea extracts may be due to potential functions in protecting the gastric mucus layer and suppressing inflammation.

Novel approach to gastric mucosal defect repair using fresh amniotic membrane allograft in dogs (experimental study)

Background

Gastric mucosal defect could result from several causative factors including the use of nonsteroidal anti-inflammatory drugs, Helicobacter pylori infection, gastrointestinal and spinal cord diseases, and neoplasia. This study was performed to achieve a novel simple, inexpensive, and effective surgical technique for the repair of gastric mucosal defect.

Methods

Six adult male mongrel dogs were divided into two groups (three dogs each). In the control positive group (C + ve), dogs were subjected to surgical induction of gastric mucosal defect and then treated using traditional medicinal treatment for such a condition. In the amniotic membrane (AM) group, dogs were subjected to the same operation and then fresh AM allograft was applied. Clinical, endoscopic, biochemical (serum protein and lipid and pepsin activity in gastric juice), histopathological, and immunohistochemistry evaluations were performed.

Results

Regarding endoscopic examination, there was no sign of inflammatory reaction around the grafted area in the AM group compared to the C + ve group. The leukocytic infiltration in the gastric ulcer was well detected in the control group and was less observed in the AM group. In the AM group, the concentrations of both protein and lipid profiles were nearly the same as those in serum samples taken preoperatively at zero time, which indicated that the AM grafting acted the same as gastric mucosa. The re-epithelization of the gastric ulcer in the C + ve group was not yet detected at 21 days, while in the AM group it was well observed covering most of the gastric ulcer. AM accelerated the re-epithelization of the gastric ulcer. The fibrous connective tissue and the precursor of collagen (COL IA1) were poorly detected in the gastric ulcer with AM application.

Conclusion

Using fresh AM allograft for repairing gastric mucosal defect in dogs showed great impact as a novel method to achieve optimum reconstruction of the gastric mucosal architecture and restoration of pre-epithelial, epithelial, and post-epithelial normal gastric mucosal barriers.

Gastroduodenal Ulceration in Small Animals: Part 1. Pathophysiology and Epidemiology

Gastroduodenal ulceration in small animals is a complex and important comorbidity that occurs when the physiological homeostasis of the gastrointestinal tract is disrupted secondary to administration of medications or the presence of local or systemic diseases. The aim of this article is to provide a comprehensive review of the veterinary literature regarding the pathophysiology, epidemiology, and risk factors associated with gastroduodenal ulceration in small animals. Pertinent concepts from the human literature will be integrated into the discussion. This article serves as an introduction to the second part of this series, which will review current evidence regarding the use of H2-receptor antagonists and proton pump inhibitors in small animals.

Nanocrystalline cerium dioxide efficacy for prophylaxis of erosive and ulcerative lesions in the gastric mucosa of rats induced by stress

In our previous works, the important therapeutic properties of nanocrystalline cerium dioxide such as strong antioxidant ability, prebiotical and antibiotic activity were shown. Such properties were obtained due to stabilization of nanoparticles with precise size 3-7nm. Such modification of nanocrystalline cerium dioxide has contributed to its remarkable efficacy and low toxicity. We have carried out the investigation of toxicity of the nanodrug and revealed that in the condition of the acute toxicity test, LD 50 was 2000mg/kg when it was administered per os. This indicator is approximately 1000 times greater than effective dose of the compound that proved the possibility of its usage for humans. Considering the strong antioxidant properties of this substance, we have performed the investigation of the influence of nanocrystalline cerium dioxide on the erosive-ulcerative lesions in gastric mucosa of rats induced by Selye's restraint stress. It was established that the studied compound significantly reduced the lesions area by 58.3% (p<0.05) induced by Selye's restraint stress. The attenuation of inflammation and decrease of lipid peroxidation in the conditions of gastric lesions and prophylactic administration of nanocrystalline cerium dioxide were shown. That was confirmed by the decrease of pro-inflammatory cytokines content (interleukin (IL) 1β, 12B p40) and raise of anti-inflammatory cytokines content (IL-10 and transforming growth factor β). Measurement of lipid peroxidation products has proved the antioxidant properties of nanocrystalline cerium dioxide as it decreased the content of conjugated dienes and thiobarbituric acid active products in the conditions of gastric ulceration induced by stress.

Gastric acid inhibitory and gastric protective effects of Cannabis and cannabinoids

Cannabis sativa has long been known for its psychotropic effect. Only recently with the discovery of the cannabinoid receptors, their endogenous legends and the enzymes responsible for their synthesis and degradation, the role of this 'endocannabinoid system' in different pathophysiologic processes is beginning to be delineated. There is evidence that CB1 receptor stimulation with synthetic cannabinoids or Cannabis sativa extracts rich in Δ(9)-tetrahydrocannabinol inhibit gastric acid secretion in humans and experimental animals. This is specially seen when gastric acid secretion is stimulated by pentagastrin, carbachol or 2-deoxy-d-glucose. Cannabis and/or cannabinoids protect the gastric mucosa against noxious challenge with non-steroidal anti-inflammatory drugs, ethanol as well as against stress-induced mucosal damage. Cannabis/cannabinoids might protect the gastric mucosa by virtue of its antisecretory, antioxidant, anti-inflammatory, and vasodilator properties.

Effects of kramecyne on LPS induced chronic inflammation and gastric ulcers

Preclinical Research Krameria cytisoides is used for the treatment of inflammation, stomach pain, and gastric ulcers. The active ingredient from this plant is a peroxide, kramecyne (KACY) which has anti-inflammatory effects. The aim of the present study was to evaluate the anti-inflammatory activities of KACY in lipopolysaccharide (LPS)-induced systemic chronic inflammation in mice for 60 days, using dexamethasone (DEX) as the positive control, vehicle (the LPS group) as the negative control and the control group (mice without inflammation). KACY did not affect survival, body weight or relative organ weight in mice but it: decreased nitric oxide (NO) production by 68%; prostaglandin E2 (PGE2 ) by 67%; increased release of anti-inflammatory cytokine IL-10 (2.0-fold), and reduced production of the proinflammatory cytokines, IL-6 (2.0-fold), IL-1β (2.4-fold), and TNF-α (2.0-fold). Furthermore, the gastroprotective effects of KACY in mice were evaluated in an ethanol-induced gastric ulcer model. The results showed that KACY at 50 and 100 mg/kg exerted gastroprotective effects with similar activity to 50 mg/kg ranitidine. In gastric tissues, KACY decreased the level of malondialdehyde (MDA) but increased the catalase (CAT) activity. KACY have potential for the treatment of chronic inflammatory diseases due its similar activity to that of DEX. It also has gastroprotective effects.

Evaluation of the safety, gastroprotective activity and mechanism of action of standardised leaves infusion extract of Copaifera malmei Harms

ETHNOPHARMACOLOGICAL RELEVANCE

Copaifera malmei Harms (Fabaceae) is a plant that occurs in the central region of Brazil, where the plant's leaves infusion is popularly used to treat gastric ulcer and inflammatory diseases. This study was aimed to investigate the gastroprotective activity and mode of action of the plants' leaves infusion in order to establish the scientific basis for such usage, and to assess its potential as a source of an anti-ulcer agent.

MATERIALS AND METHODS

Leaves infusion extract of the plant (SIECm) was prepared, freeze dried and lyophilised. Its qualitative and quantitative phytochemical constituents were investigated using TLC and HPLC techniques. The safety profile was evaluated on CHO-k1 epithelial cells viability using the Alamar blue assay, and by acute toxicity test in mice. The gastroprotection and anti-ulcer efficacy of the SIECm (25, 100 and 400mg/kg, p.o.) were tested using acute (acidified ethanol, piroxicam and water restrain stress), and chronic (acetic acid) experimental ulcer models. The plausible mode of action of the SIECm was assessed using gastric secretion, gastric barrier mucus, nitric oxide, and its antioxidant (myeloperoxidase and catalase) effects in mice and rats. The histopathological analyses of the ulcerated tissues as well as the extract's activity on Helicobacter pylori were also investigated.

RESULTS

Phytochemical tests indicated the presence of mainly phytosterols, phenolics and flavonoids. The SIECm exhibited no cytotoxic effects on the CHO-k1 cells, and no oral acute toxicity in mice. It prevented against the acute induced ulcerations by enhancing gastroprotection through gastric mucus production, NO modulation, antioxidant, reduced gastric secretion and enhanced chronic ulcers healing process, as shown by reduction/prevention of epithelial and vascular damage, in addition to reduction in leucocyte infiltration. The SIECm however did not exhibit activity against H. pylori.

CONCLUSION

The SIECm is safe, contain useful phytochemicals and exhibited significant gastroprotective/anti-ulcer effects. The results justify its folkloric usage, and provided scientific evidence of its potential as a source of new phytodrug to treat gastric ulcers.

Does the gastroprotective action of a medicinal plant ensure healing effects? An integrative study of the biological effects of Serjania marginata Casar. (Sapindaceae) in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Serjania marginata (Sapindaceae), a medicinal plant commonly found in the Brazilian Cerrado, Paraguay, Bolivia and Argentina, is also known as "cipó-uva" or "cipó-timbó". Ethnopharmacological studies indicate that the leaves from this medicinal plant are used in folk medicine to treat gastric pain. The overall objective of this study was to evaluate the gastroprotective and healing effect of the hydroalcoholic extract obtained from S. marginata (HESM) leaves using rodent experimental models. As part of the integrative study of this medicinal plant, we also evaluated the acute toxicity, antimicrobial, antidiarrheal, (anti)mutagenic, and hemodynamic effects.

MATERIAL AND METHODS

We performed a pharmacological study to test the acute toxicity and antimutagenic effect (Ames assay) of the HESM. The HESM was tested against different necrosis-promoting agents and experimental manipulations, such as absolute ethanol, cysteamine, pyloric ligature, and ischemia-reperfusion (I/R) injury. The gastroprotective effect of the HESM was assessed by analyzing the gastric juice (volume, pH, total acidity) and the mucus in the gastric mucosa from rats. We assessed the levels of NO, sulfhydryl compounds, PGE2, vanilloid receptor, glutathione (GSH), and malondialdehyde (MDA), as well as the myeloperoxidase (MPO) activity. The gastric healing effects of the HESM were evaluated during 7 or 14 days of treatment. The intestinal motility, antidiarrheal action, and antibacterial effects (microdilution methods) of the HESM were also evaluated.

RESULTS

The phytochemical analysis of the HESM revealed the presence of saponins, flavonoid glycosides, and tannins. The extract exhibited no sign of acute toxicity or mutagenic effect in vitro. In contrast, this extract exhibited a protective effect against the mutagenic action of direct- and indirect-acting mutagens. Only the oral administration of HESM (250mg/kg) significantly decreased the severity of gastric damage induced by ethanol (60.13%) and I/R (58.31%). The HESM exerts its gastroprotective effects by decreasing the MPO and MDA activities in the gastric tissue and by increasing the amount of adherent mucus covering the gastric mucosa. In vitro, the extract also displayed evident antimicrobial effects against Helicobacter pylori. However, the preventive effect of the HESM was not accompanied by an ulcer-healing effect. The treatment with HESM (14 days) significantly increased gastric lesions in 99% of the tested animals compared with the control group. This result represents a highly relevant piece of evidence that should resonate as an alert against the chronic use of this medicinal plant as an antiulcer in folk medicine.

CONCLUSIONS

Despite the anti-H. pylori and gastroprotective actions of S. marginata in experimental models, the gastric injuries aggravation induced after chronic treatment with the HESM argues against the use of this plant species in folk medicine.

Translational Implications of the Alcohol-Metabolizing Enzymes, Including Cytochrome P450-2E1, in Alcoholic and Nonalcoholic Liver Disease

Fat accumulation (hepatic steatosis) in alcoholic and nonalcoholic fatty liver disease is a potentially pathologic condition which can progress to steatohepatitis (inflammation), fibrosis, cirrhosis, and carcinogenesis. Many clinically used drugs or some alternative medicine compounds are also known to cause drug-induced liver injury, which can further lead to fulminant liver failure and acute deaths in extreme cases. During liver disease process, certain cytochromes P450 such as the ethanol-inducible cytochrome P450-2E1 (CYP2E1) and CYP4A isozymes can be induced and/or activated by alcohol and/or high-fat diets and pathophysiological conditions such as fasting, obesity, and diabetes. Activation of these P450 isozymes, involved in the metabolism of ethanol, fatty acids, and various drugs, can produce reactive oxygen/nitrogen species directly and/or indirectly, contributing to oxidative modifications of DNA/RNA, proteins and lipids. In addition, aldehyde dehydrogenases including the mitochondrial low Km aldehyde dehydrogenase-2 (ALDH2), responsible for the metabolism of acetaldehyde and lipid aldehydes, can be inactivated by various hepatotoxic agents. These highly reactive acetaldehyde and lipid peroxides, accumulated due to ALDH2 suppression, can interact with cellular macromolecules DNA/RNA, lipids, and proteins, leading to suppression of their normal function, contributing to DNA mutations, endoplasmic reticulum stress, mitochondrial dysfunction, steatosis, and cell death. In this chapter, we specifically review the roles of the alcohol-metabolizing enzymes including the alcohol dehydrogenase, ALDH2, CYP2E1, and other enzymes in promoting liver disease. We also discuss translational research opportunities with natural and/or synthetic antioxidants, which can prevent or delay the onset of inflammation and liver disease.

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.

[Expression of plasminogen activator system components in the gastric mucosa in portal hypertensive gastropathy]

OBJECTIVE

to study the expression of urokinase-type plasminogen activator (uPA) and plasminogen activator inhibitor-1 (PAI-1) in the gastric mucosal (GM) vascular endothelium and epithelial cells of patients with portal hypertensive gastropathy (PHG) and those with portal hypertension (PH) without signs of PHG as compared to a control group.

MATERIAL AND METHODS

GM biopsy specimens from patients with PHG, those with PH without signs of PHG, and controls with the normal gastric mucosa were immunohistochemically examined.

RESULTS

Comparison of the expression of uPA in the GM vascular endothelium and epithelial vessels revealed no significant differences in the patient groups. The level of PAI-1 in the GM vessels was statistically significantly higher in the control group than in the groups of patients with PHG and PH without PHG. PAI-1 expression in the GM epithelial cells was significantly more commonly absent in the PHG group than in the control group. An analysis of an uPA and PAI-1 expression ratio showed a statistically significant predominance of the expression of uPA over its inhibitor in the GM vascular endothelium of the patients with PHG and those with PH without PHG as compared to the controls.

CONCLUSION

The predominance of uPA over PAI-1 in the GM vessels and epithelial cells can play a role in the development of GM bleeding.

Gastroprotective effect of alpha-pinene and its correlation with antiulcerogenic activity of essential oils obtained from Hyptis species

Background:

Alpha-pinene (α-pinene) is a monoterpene commonly found in essential oils with gastroprotective activity obtained from diverse medicinal plants, including Hyptis species. The genus Hyptis (lamiaceae) consists of almost 400 species widespread in tropical and temperate regions of America. In the north and northeastern Brazil, some Hyptis species are used in traditional medicine to treat gastrointestinal disturbances.

Objective:

The present study has investigated the gastoprotective effect of purified α-pinene in experimental gastric ulcer induced by ethanol and indomethacin in mice.

Materials and Methods:

Gastric ulcers were induced in male Swiss mice (20-30 g) by oral administration of absolute ethanol or indomethacin 45 min after oral pretreatment with vehicle, standard control drugs or α-pinene (10, 30, and 100 mg/kg). One hour after the ulcerative challenges, the stomach were removed, and gastric lesions areas measured. The effects of α-pinene on the gastric juice acidity were determined by pylorus ligation model. The gastrointestinal motility and mucus depletion were determined by measuring the gastric levels of phenol red and alcian blue, respectively. Hematoxylin and eosin stained sections of gastric mucosa of the experimental groups were used for histology analysis.

Results:

α-pinene pretreatment inhibited ethanol-induced gastric lesions, reduced volume and acidity of the gastric juice and increased gastric wall mucus (P < 0.05). Furthermore, we showed an interesting correlation between concentration of α-pinene and gastroprotective effect of Hyptis species (P Pearson = 0.98).

Conclusion:

Our data showed that the α-pinene exhibited significant antiulcerogenic activity and a great correlation between concentration of α-pinene and gastroprotective effect of Hyptis species was also observed.

Seasonal changes in gastric mucosal factors associated with peptic ulcer bleeding

A close association has been established between climate and peptic ulcer bleeding (PUB). The incidence of PUB in cold climates is significantly higher than that in hot climates. In this study, gastric mucosal damage and its barrier function (through associated barrier factors) in extreme climate conditions were examined to investigate the pathogenesis of PUB in extreme cold climates. Gastric juice and biopsy specimens were collected from 176 patients with peptic ulcer. Conventional hematoxylin and eosin staining was used to exclude malignant ulcers. Helicobacter pylori infections were detected by modified Giemsa staining. pH values of the gastric juice samples were obtained on-site by precise pH dipstick readings. The protein expression levels of heat shock protein (HSP) 70, occludin, nitric oxide synthase (NOS), epidermal growth factor (EGF) and EGF receptor (EGFR) in the gastric mucosa were detected by immunohistochemistry. No significant differences were identified between the high and low bleeding risk groups in the rates of H. pylori infection and the pH values of the gastric juices in the extreme hot or cold climates. Furthermore, no statistically significant differences were identified in the protein expression levels of occludin, NOS, EGF and EGFR between the high and low bleeding risk groups. In the extreme cold climate, the expression of HSP70 and the mucus thickness of the gastric antrum in the high bleeding risk group were significantly lower than those in the low bleeding risk group. The protein expression levels of occludin, HSP70, NOS and EGFR in the extreme cold climate were significantly lower than those in the extreme hot climate, whereas the gastric acid secretion was significantly higher in the extreme cold climate than that in the extreme hot climate. In conclusion, low expression of HSP70 in the gastric mucosa and reduced gastric mucus thickness may play key roles in the mechanism of PUB in extreme cold climates. The significant decrease in barrier factors and increase in damage in extreme cold climates may be associated with the seasonal pattern of peptic ulcers.

Protective effects of Croton campestris A. St-Hill in different ulcer models in rodents: evidence for the involvement of nitric oxide and prostaglandins

ETHNOPHARMACOLOGICAL RELEVANCE

Croton campestris A. St.-Hill., popularly known as "velame do campo", is a species native from savannah area of Northeast Brazil, which is used by traditional communities in folk medicine for a variety of health problems, especially detoxification, inflammation and gastritis. The present study investigates the possible gastric antiulcer activity of Croton campestris root extract (CCRE) and mechanisms of action underlying this effect.

MATERIALS AND METHODS

Gastric lesions were induced in mice by ethanol, acidified ethanol and indomethacin. CCRE was previously administered orally in doses ranging from 50 to 750 mg/kg. Stomach lesions were measured. The involvement of Nitric Oxide (NO), prostaglandins (PGEs), ATP-dependent K+ channel and adrenergic receptor was investigated through specific inhibitors.

RESULTS

CCRE produced significant antiulcer activity against absolute ethanol, acidified ethanol and indomethacin induced gastric lesions. The pretreatment with L-NAME (10 mg/kg, p.o.), an inhibitor of nitric oxide synthesis and indomethacin (10 mg/kg, s.c.), an inhibitor of prostaglandin production, reversed the antiulcer action of CCRE.

CONCLUSION

Taking together, these results suggest that the antiulcer activity of CCRE is dependent of NO and prostaglandin pathways possibly due to its ability to stimulate the synthesis of NO, and activation of endogenous prostaglandin production. Therefore, the use of CCRE in traditional Brazilian medicine against gastric disorders has a scientific basis.

Increased susceptibility of aging gastric mucosa to injury: The mechanisms and clinical implications

This review updates the current views on aging gastric mucosa and the mechanisms of its increased susceptibility to injury. Experimental and clinical studies indicate that gastric mucosa of aging individuals-“aging gastropathy”-has prominent structural and functional abnormalities vs young gastric mucosa. Some of these abnormalities include a partial atrophy of gastric glands, impaired mucosal defense (reduced bicarbonate and prostaglandin generation, decreased sensory innervation), increased susceptibility to injury by a variety of damaging agents such as ethanol, aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs), impaired healing of injury and reduced therapeutic efficacy of ulcer-healing drugs. Detailed analysis of the above changes indicates that the following events occur in aging gastric mucosa: reduced mucosal blood flow and impaired oxygen delivery cause hypoxia, which leads to activation of the early growth response-1 (egr-1) transcription factor. Activation of egr-1, in turn, upregulates the dual specificity phosphatase, phosphatase and tensin homologue deleted on chromosome ten (PTEN) resulting in activation of pro-apoptotic caspase-3 and caspase-9 and reduced expression of the anti-apoptosis protein, survivin. The imbalance between pro- and anti-apoptosis mediators results in increased apoptosis and increased susceptibility to injury. This paradigm has human relevance since increased expression of PTEN and reduced expression of survivin were demonstrated in gastric mucosa of aging individuals. Other potential mechanisms operating in aging gastric mucosa include reduced telomerase activity, increase in replicative cellular senescence, and reduced expression of vascular endothelial growth factor and importin-α-a nuclear transport protein essential for transport of transcription factors to nucleus. Aging gastropathy is an important and clinically relevant issue because of: (1) an aging world population due to prolonged life span; (2) older patients have much greater risk of gastroduodenal ulcers and gastrointestinal complications (e.g., NSAIDs-induced gastric injury) than younger patients; and (3) increased susceptibility of aging gastric mucosa to injury can be potentially reduced or reversed pharmacologically.

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.

Pharmacological evidence for the participation of NO-cGMP-KATP pathway in the gastric protective effect of curcumin against indomethacin-induced gastric injury in the rat

Curcumin, main compound obtained from rizhoma of Curcuma longa, shows antitumoral, antioxidant, anticarcinogenic and gastric protective properties. Recently, it has been demonstrated that curcumin exerts its gastric protective action due to an increase in gastric nitric oxide (NO) levels. However, it is unknown whether these increased NO levels are associated with activation of intracellular signaling pathways. Thus, the purpose of this study was to investigate the role of NO-cGMP-KATP pathway in the gastric protective effect of curcumin during indomethacin-induced gastric injury in the rat. Adult female Wistar rats were gavaged with curcumin (3-300mg/kg, p.o.) or omeprazole (30mg/kg, p.o.) 30min before indomethacin insult (30mg/kg, p.o.). Other groups of rats were administered L-NAME (70mg/kg, i.p.; inhibitor of nitric oxide synthase), ODQ (10mg/kg, i.p.; inhibitor of soluble guanylate cyclase) or glibenclamide (1mg/kg, i.p.; blocker of ATP-sensitive potassium (KATP) channels) 30min before curcumin (30mg/kg, p.o.). 3h after indomethacin administration, rats were sacrificed and gastric injury was evaluated by determining total damaged area. A sample of gastric tissue was harvested and processed to quantify organic nitrite levels. Curcumin significantly protected against indomethacin-induced gastric injury and this effect was comparable to gastroprotective effect by omeprazole. L-NAME, ODQ and glibenclamide significantly prevented the curcumin-mediated gastric protective effect in the indomethacin-induced gastric injury model. Furthermore, curcumin administration induced a significant increase in gastric nitric oxide levels as compared to vehicle administration. Our results show for the first time that curcumin activates NO/cGMP/KATP pathway during its gastro protective action.

Gastroprotective effects of the essential oil of Hyptis crenata Pohl ex Benth. on gastric ulcer models

ETHNOPHARMACOLOGICAL RELEVANCE

Hyptis crenata Pohl ex Benth (Lamiaceae), popularly known as "hortelã-brava" or "hortelã do campo", is widely distributed in the northeast of Brazil. In Brazil, the leaves of this plant have been used in traditional medicine for the treatment of gastrointestinal disturbances, including gastric ulcers. In an attempt to experimentally validate this claimed antiulcerogenic activity, the gastroprotective effects of the essential oil extracted from the leaves of the Hyptis crenata Pohl ex Benth (EOHc) were evaluated in recognized gastric ulcer models in mice.

MATERIALS AND METHODS

EOHc was obtained by hydrodistillation and analyzed using gas chromatography-mass spectrometry (GC-MS). Swiss male mice (25-30g) were used for the studies. The gastric ulcers were induced by oral administration of absolute ethanol or indomethacin 45min after oral pretreatment with EOHc, vehicle and positive control drugs. One hour after the ulcerative challenges, the stomachs were removed and the area of the lesions was measured. The volume, pH and total acidity of the gastric secretions were determined using the pylorus ligature model. The gastrointestinal motility was measured using gastric emptying and intestinal transit. The ethanol-induced gastric mucus depletion and lipid peroxidation were also analyzed.

RESULTS

Our findings are as follows: A significant inhibition of gastric lesions induced by absolute ethanol was observed in the mice pre-treated with EOHc, at a dose of 30 and 100 and 300mg/kg (5.56±1.51, 2.88±0.82 and 1.71±0.54mm(2), respectively) compared to control group (118.03±35.4mm(2)). Also, EOHc (300mg/kg) produced a gastroprotective effect against the gastric lesions induced by indomethacin (16.07±4.68mm(2)) compared to control group (38.64±6.1mm(2)). EOHc pretreatment produced a reduction in the ethanol-induced lipid peroxidation from 3.9±0.22 to 2.4±0.1μmol/mg tissue (EOHc-300mg/kg and control group, respectively). We also observed that EOHc pretreatment decreased the gastric emptying, but did not alter the intestinal transit ratio, ethanol-induced depletion of the gastric wall mucus or secretion parameters (volume, pH and [H(+)]).

CONCLUSION

Our data indicate that EOHc exerts a gastroprotective effect, indicated by its significant inhibition of gastric lesions in ethanol- and indomethacin-induced ulcer models, which may be associated with its accelerating effect on gastric emptying and reduction in oxidative damages. Our data suggest a potential therapeutic application for EOHc in the treatment of gastric ulcers.