Bacteria rapidly colonize and modulate healing of gastric ulcers in rats

Probiotics as a Therapeutic Approach for Non-infectious Gastric Ulcer Management: a Comprehensive Review

A gastric ulcer is a stomach lining or nearby intestine disruption caused by acid and pepsin. Helicobacter pylori (H. pylori) and NSAIDs are the primary culprits behind stomach infections that can lead to gastric ulcers and other digestive disorders. Additionally, lifestyle choices such as alcohol consumption and cigarette smoking, stress, and exposure to cold environments can also contribute to non-infectious gastric ulcers. Various treatments are available for gastric ulcers, including antibiotics, anticholinergics, and antacids. However, potential concerns include antibiotic resistance, side effects, and treatment failure. Considering this, there is a need for an alternative approach to manage it. Fortunately, probiotics, typically Lactobacillus and Bifidobacterium, show potential for healing gastric ulcers, offering a non-invasive alternative to conventional treatments. A notable concern arises from applying probiotic bacteria stemming from the propensity of pathogenic bacteria to develop antimicrobial resistance in response to antibiotic therapies. Therefore, the use of yeast becomes more imperative due to its natural resistance to antibacterial antibiotics for antibacterial-treated patients. Probiotic bacteria and yeasts could heal gastric ulcers by regulating the immune response, reducing inflammation, and restoring the balance between defensive and aggressive factors of the gastric layer. This comprehensive review provides an in-depth analysis of the benefits of probiotics and their potential as a therapeutic treatment for non-infectious gastric ulcers, along with other probiotic options. In particular, this review provides a succinct summary of multiple literature studies on probiotics, emphasising the distinctive properties of yeast probiotics, as well as their (bacteria and yeasts) application in the management of non-infectious gastric ulcers.

Effect of diet composition on glandular gastric disease in horses

BACKGROUND

Nutritional factors are suggested to influence the incidence and severity of glandular gastric disease (GGD) in horses.

OBJECTIVES

To retrospectively assess whether dietary fermentable carbohydrates increase the severity of GGD and to prospectively evaluate whether the partial substitution of concentrates by dehydrated alfalfa would decrease GGD severity scores.

ANIMALS

In total, 82 trotters from 4 training centers exercised ≥5 days/week.

METHODS

Multicenter retrospective observational study, and prospective 2-arm randomized trial. Glandular mucosae were observed by gastroscopy and scored (0-4 severity scale) at day 0 (D0). Biochemical composition of the diet fed was compared between ulcerated and nonulcerated groups. After D0, horses either received the same diet (control, n = 41) or pelleted dehydrated alfalfa substituting 50% concentrates (alfalfa, n = 41). Glandular scores were recorded in both groups after 21 (D21) and 42 days (D42). The first end point was a successful outcome, defined as a horse with a glandular score of 2 to 4 on D0, decreasing to a score of 0 to 1 on days 21 or 42.

RESULTS

Horses scored 0 to 1 at D0 ingested more (P = .01) soluble sugars from concentrates than those scored 2 to 4 before D0 (77.5 g/kg BW; 95% confidence interval [CI]: 71.1-84.0, vs 59.1 g/kg BW; 95% CI: 48.0-70.3), whereas starch intake did not differ between groups (P = .24). Among horses scored 2 to 4 at D0, fewer were scored 2 to 4 in the alfalfa group (1 out of 6) compared with the control group (6 out of 6) at D42 (P = .02). Clinical success was 47.7 times more likely in horses fed alfalfa compared with horses in the control group (95% CI: 1.6-1422.8).

CONCLUSION AND CLINICAL IMPORTANCE

Relationships were found between diet composition and integrity of the glandular mucosa. Feeding pelleted dehydrated alfalfa could help to reduce the incidence and severity of GGD.

Overview of the angiogenic effect of probiotics (Lactobacillus acidophilus and Lactobacillus rhamnosus) at human umbilical vein endothelial cells

Introduction: Angiogenesis (neovascularization), which means new vessel construction, is normal and physiologically, wound healing, embryogenesis, a necessary menstrual cycle it's a mechanism. When taken in appropriate amounts together with or separately with nutrients, mucosal and by regulating systemic immunity, ensuring nutritional and microbial balance in the intestines living nonpatogenic microorganisms that positively affect the health of the host it is called "probiotics". Lactic acid bacteria, the most probiotic microorganisms it constitutes its important group. Where probiotics have an effect on angiogenesis, and it is thought to help heal wounds through the road. With this research indicated that roles of Lactobacillus acidophilus and Lactobacillus rhamnosus on angiogenesis if present to demonstrate in vitro methods and the gene expression responsible for the formation of these effects it is intended to reveal. Material and Method: This study is an experimental study conducted in vitro human umbilical cord vein endothelial cell (HUVEC) MTT test in cell culture with (3-[4,5-Dimethylthiazole-2-yl]-2,5-diphenyltetrazolium bromide; Thiazolyl blue) evaluation of viability and proliferation wound healing model, tube formation method and gene expression with real rime-polymer chain reaction (RT-PCR) methods of appointment were used. Results: HUVEC cells L. acidophilus 10⁹ CFU\ml after extract application statistical of mRNA expression of VEGF and FGF genes by control group 24 per hour it was found to increase significantly. L. rhamnosus 10 6 CFU\ml and 109 CFU\ml after application of extracts VEGF gene mRNA by control group 24 per hour its expression was found to be statistically significantly increased. Also L. rhamnosus extracts cell proliferation and migration of in vitro wound model it was found to increase statistically significantly. Conclusion: In this study, in vitro L. acidophilus 10⁹ CFU\ml extract and 10⁶ CFU\ml and 10⁹ CFU\ml extract of L. rhamnosus, VEGF gene mRNA revealed to be effective on angiogenesis in HUVEC cells by increasing expression it is.

Characterization of a Bacillus sp. KRF-7 isolated from the intestine of rockfish and effects of dietary supplementation with mannan oligosaccharide in rockfish aquaculture

The purpose of this study was to characterize the bacteria isolated from rockfish intestines and to investigate the effects of feed supplementation in rockfish aquaculture. Bacillus sp. KRF-7 isolated from the intestine of rockfish (Sebastes schlegelii) was demonstrated to be safe based on in vitro tests confirming the absence of hemolysis, cytotoxicity, and genes with toxigenic potential. In a feeding trial, providing a supplemental diet of 1 × 10⁸ CFU g^-1Bacillus sp. KRF-7 was observed to positively alter the weight gain, specific growth rate, feed conversion ratio, and protein efficiency ratio of juvenile rockfish. KRF-7 supplementation showed positive regulation of nonspecific immune parameters, such as superoxide dismutase, lysozyme activity, and myeloperoxidase activity. This analysis also revealed a change in the composition of the intestinal microbiota at the phylum level from Proteobacteria to Firmicutes. In both the kidney and spleen, the expression levels of IL-10, NF-κB, and B cell activating factors in the KRF-7-supplemented group were significantly increased compared to those in the control group. Therefore, this study verified the safety of KRF-7 isolated from the intestine of rockfish and suggests that dietary supplementation with KRF-7 enhances the growth performance of rockfish and has beneficial effects on the regulation of the intestinal microbiota and immune response.

Probiotics in the treatment of gastrointestinal diseases

The human microbiota has a tremendous effect on our health. In the last decades, our knowledge about interactions between bacteria and humans have grown greatly. Not only is it necessary for humans to synthesize vitamins, to have tight intestinal barriers or protect from pathogens, it also has an impact on our immune system and thus plays an important role in autoimmune diseases and prevention of excessive inflammatory response. The idea of probiotics is to restore the balance in humans digestive microbiota. There is a growing number of scientific papers that proves a positive impact of using probiotics in various diseases. However, there are still questions that need to be answered before probiotics play a bigger role in the treatment. This paper presents the information about the use of probiotics in most common diseases of gastrointestinal tract.

Modulation of Stem Cell Progeny by Probiotics during Regeneration of Gastric Mucosal Erosions

Patients with gastric mucosal erosions are predisposed to chronic gastritis, ulcer or even cancer. The repair of mucosal erosions involves several events including proliferation of gastric epithelial stem cells. The aim of this study was to investigate the effects of the probiotic mixture of De Simone Formulation on gastric epithelial stem cell lineages in mouse models of gastric mucosal erosions. Gastric erosions were induced by a single oral gavage of 80% ethanol containing 15 mg/mL acetylsalicylic acid (5 mL/kg) following a daily dose of probiotic mixture (5 mg/day/mouse) for 10 days. In another protocol, erosions were induced by a daily gavage of acetylsalicylic acid (400 mg/kg/day/mouse) for 5 days before or after daily administration of probiotic mixture for 5 days. Control mice received water gavage for 10 days. All mice were injected with bromodeoxyuridine two hours before sacrifice to label S-phase cells. The stomachs of all mice were processed for histological examination, lectin binding, and immunohistochemical analysis. The results reveal that mice that received probiotics before or after the induction of erosion showed a decrease in erosion index with an increase in gastric epithelial stem/progenitor cell proliferation and enhanced production of mucus, trefoil factors, and ghrelin by mucous and enteroendocrine cell lineages. These mice also showed restoration of the amount of H⁺,K⁺-ATPase and pepsinogen involved in the production of the harsh acidic environment by parietal and chief cell lineages. In conclusion, this study demonstrates the beneficial effects of probiotics against gastric mucosal erosion and highlights the involvement and modulation of proliferative stem cells and their multiple glandular epithelial cell lineages.

The Nonsteroidal Anti-Inflammatory Drug Ketorolac Alters the Small Intestinal Microbiota and Bile Acids Without Inducing Intestinal Damage or Delaying Peristalsis in the Rat

Background: Nonsteroidal anti-inflammatory drugs (NSAIDs) induce significant damage to the small intestine, which is accompanied by changes in intestinal bacteria (dysbiosis) and bile acids. However, it is still a question of debate whether besides mucosal inflammation also other factors, such as direct antibacterial effects or delayed peristalsis, contribute to NSAID-induced dysbiosis. Here we aimed to assess whether ketorolac, an NSAID lacking direct effects on gut bacteria, has any significant impact on intestinal microbiota and bile acids in the absence of mucosal inflammation. We also addressed the possibility that ketorolac-induced bacterial and bile acid alterations are due to a delay in gastrointestinal (GI) transit. Methods: Vehicle or ketorolac (1, 3 and 10 mg/kg) were given to rats by oral gavage once daily for four weeks, and the severity of mucosal inflammation was evaluated macroscopically, histologically, and by measuring the levels of inflammatory proteins and claudin-1 in the distal jejunal tissue. The luminal amount of bile acids was measured by liquid chromatography-tandem mass spectrometry, whereas the composition of microbiota by sequencing of bacterial 16S rRNA. GI transit was assessed by the charcoal meal method. Results: Ketorolac up to 3 mg/kg did not cause any signs of mucosal damage to the small intestine. However, 3 mg/kg of ketorolac induced dysbiosis, which was characterized by a loss of families belonging to Firmicutes (Paenibacillaceae, Clostridiales Family XIII, Christensenellaceae) and bloom of Enterobacteriaceae. Ketorolac also changed the composition of small intestinal bile by decreasing the concentration of conjugated bile acids and by increasing the amount of hyodeoxycholic acid (HDCA). The level of conjugated bile acids correlated negatively with the abundance of Erysipelotrichaceae, Ruminococcaceae, Clostridiaceae 1, Muribaculaceae, Bacteroidaceae, Burkholderiaceae and Bifidobacteriaceae. Ketorolac, under the present experimental conditions, did not change the GI transit. Conclusion: This is the first demonstration that low-dose ketorolac disturbed the delicate balance between small intestinal bacteria and bile acids, despite having no significant effect on intestinal mucosal integrity and peristalsis. Other, yet unidentified, factors may contribute to ketorolac-induced dysbiosis and bile dysmetabolism.

Gut Microbiota in NSAID Enteropathy: New Insights From Inside

As a class of the commonly used drugs in clinical practice, non-steroidal anti-inflammatory drugs (NSAIDs) can cause a series of adverse events including gastrointestinal injuries. Besides upper gastrointestinal injuries, NSAID enteropathy also attracts attention with the introduction of capsule endoscopy and double balloon enteroscopy. However, the pathogenesis of NSAID enteropathy remains to be entirely clarified. Growing evidence from basic and clinical studies presents that gut microbiota is a critical factor in NSAID enteropathy progress. We have reviewed the recent data about the interplay between gut microbiota dysbiosis and NSAID enteropathy. The chronic medication of NSAIDs could change the composition of the intestinal bacteria and aggravate bile acids cytotoxicity. Meanwhile, NSAIDs impair the intestinal barrier by inhibiting cyclooxygenase and destroying mitochondria. Subsequently, intestinal bacteria translocate into the mucosa, and then lipopolysaccharide released from gut microbiota combines to Toll-like receptor 4 and induce excessive production of nitric oxide and pro-inflammatory cytokines. Intestinal injuries present in the condition of intestinal inflammation and oxidative stress. In this paper, we also have reviewed the possible strategies of regulating gut microbiota for the management of NSAID enteropathy, including antibiotics, probiotics, prebiotics, mucosal protective agents, and fecal microbiota transplant, and we emphasized the adverse effects of proton pump inhibitors on NSAID enteropathy. Therefore, this review will provide new insights into a better understanding of gut microbiota in NSAID enteropathy.

The Probiotic Lactobacillus rhamnosus for Alleviation of Helicobacter pylori-Associated Gastric Pathology in East Africa

The probiotic Lactobacillus rhamnosus GG (LGG) can play a role in establishing a harmless relationship with Helicobacter pylori and reduce gastric pathology in East African populations. H. pylori has the ability to inhabit the surface of the mucous layer of the human stomach and duodenum. In the developing world, an estimated 51% of the population is carrier of H. pylori, while in some Western countries these numbers dropped below 20%, which is probably associated with improved sanitation and smaller family sizes. Colonization by H. pylori can be followed by inflammation of the gastric mucus layer, and is a risk factor in the development of atrophic gastritis, peptic ulcers and gastric cancer. Notwithstanding the higher prevalence of H. pylori carriers in developing countries, no equal overall increase in gastric pathology is found. This has been attributed to a less pro-inflammatory immune response to H. pylori in African compared to Caucasian populations. In addition, a relatively low exposure to other risk factors in certain African populations may play a role, including the use of non-steroidal anti-inflammatory drugs, smoking, and diets without certain protective factors. A novel approach to the reduction of H. pylori associated gastric pathology is found in the administration of the probiotic bacterium Lactobacillus rhamnosus yoba 2012 (LRY), the generic variant of LGG. This gastro-intestinal isolate inhibits H. pylori by competition for substrate and binding sites as well as production of antimicrobial compounds such as lactic acid. In addition, it attenuates the host's H. pylori-induced apoptosis and inflammation responses and stimulates angiogenesis in the gastric and duodenal epithelium. The probiotic LRY is not able to eradicate H. pylori completely, but its co-supplementation in antibiotic eradication therapy has been shown to relieve side effects of this therapy. In Uganda, unlike other African countries, gastric pathology is relatively common, presumably resulting from the lack of dietary protective factors in the traditional diet. Supplementation with LRY through local production of probiotic yogurt, could be a solution to establish a harmless relationship with H. pylori and reduce gastric pathology and subsequent eradication therapy treatment.

Patterns of host gene expression associated with harboring a foregut microbial community

BACKGROUND

Harboring foregut microbial communities is considered a key innovation that allows herbivorous mammals to colonize new ecological niches. However, the functions of these chambers have only been well studied at the molecular level in ruminants. Here, we investigate gene expression in the foregut chamber of herbivorous rodents and ask whether these gene expression patterns are consistent with results in ruminants. We compared gene expression in foregut tissues of two rodent species: Stephen's woodrat (Neotoma stephensi), which harbors a dense foregut microbial community, and the lab rat (Rattus norvegicus), which lacks such a community.

RESULTS

We found that woodrats have higher abundances of transcripts associated with smooth muscle processes, specifically a higher expression of the smoothelin-like 1 gene, which may assist in contractile properties of this tissue to retain food material in the foregut chamber. The expression of genes associated with keratinization and cornification exhibited a complex pattern of differences between the two species, suggesting distinct molecular mechanisms. Lab rats exhibited higher abundances of transcripts associated with immune function, likely to inhibit microbial growth in the foregut of this species.

CONCLUSIONS

Some of our results were consistent with previous findings in ruminants (high expression of facilitative glucose transporters, lower expression of B4galnt2), suggestive of possible convergent evolution, while other results were unclear, and perhaps represent novel host-microbe interactions in rodents. Overall, our results suggest that harboring a foregut microbiota is associated with changes to the functions and host-microbe interactions of the foregut tissues.

Potential role of probiotics in the management of gastric ulcer

Gastric ulcer is one of the most common chronic gastrointestinal diseases characterized by a significant defect in the mucosal barrier. Helicobacter pylori (H. pylori) infection and the frequent long-term use of non-steroidal anti-inflammatory drugs are major factors involved in gastric ulcer development. Acid inhibitors and antibiotics are commonly used to treat gastric ulcer. However, in the last few decades, the accumulating evidence for resistance to antibiotics and the side effects of antibiotics and acid inhibitors have drawn attention to the possible use of probiotics in the prevention and treatment of gastric ulcer. Probiotics are live microorganisms that when administered in adequate amounts confer health benefits on the host. Currently, the available experimental and clinical studies indicate that probiotics are promising for future applications in the management of gastric ulcers. This review aims to provide an overview of the general health benefits of probiotics on various systemic and gastrointestinal disorders with a special focus on gastric ulcer and the involved cellular and molecular mechanisms: i) Protection of gastric mucosal barrier; ii) upregulation of prostaglandins, mucus, growth factors and anti-inflammatory cytokines; iii) increased cell proliferation to apoptosis ratio; and iv) induction of angiogenesis. Finally, some of the available data on the possible use of probiotics in H. pylori eradication are discussed.

Cell Systems to Investigate the Impact of Polyphenols on Cardiovascular Health

Polyphenols are a diverse group of micronutrients from plant origin that may serve as antioxidants and that contribute to human health in general. More specifically, many research groups have investigated their protective effect against cardiovascular diseases in several animal studies and human trials. Yet, because of the excessive processing of the polyphenol structure by human cells and the residing intestinal microbial community, which results in a large variability between the test subjects, the exact mechanisms of their protective effects are still under investigation. To this end, simplified cell culture systems have been used to decrease the inter-individual variability in mechanistic studies. In this review, we will discuss the different cell culture models that have been used so far for polyphenol research in the context of cardiovascular diseases. We will also review the current trends in cell culture research, including co-culture methodologies. Finally, we will discuss the potential of these advanced models to screen for cardiovascular effects of the large pool of bioactive polyphenols present in foods and their metabolites.

Deciphering the pathogenesis of NSAID enteropathy using proton pump inhibitors and a hydrogen sulfide-releasing NSAID

The small intestine is a significant site of ulceration and bleeding induced by nonsteroidal anti-inflammatory drugs (NSAIDs). The pathogenesis is poorly understood. The present study explored the roles of bile, bacteria, and enterohepatic circulation to NSAID enteropathy, using both a conventional NSAID (naproxen) and a gastrointestinal-safe naproxen derivative (ATB-346), as well as proton pump inhibitors (PPIs). Rats were treated orally with naproxen or equimolar doses of ATB-346 over a 5-day period, with or without PPI administration, and intestinal damage was quantified. The cytotoxicity of bile from the rats was evaluated in vitro. Biliary excretion of naproxen and ATB-346 was determined. The impact of the NSAIDs and of PPIs on the composition of the intestinal microbiota was examined by deep sequencing of 16s rRNA. Naproxen caused significant intestinal damage and inflammation, whereas ATB-346 did not. Naproxen, but not ATB-346, dose dependently increased the cytotoxicity of bile, and it was further increased by PPI coadministration. Whereas biliary excretion of naproxen was significant in naproxen-treated rats, it was greatly reduced in rats treated with ATB-346. The enteric microbiota of naproxen-treated rats was distinct from that in vehicle- or ATB-346-treated rats, and PPI administration caused significant intestinal dysbiosis. The increase in cytotoxicity of bile induced by naproxen and PPIs may contribute significantly to intestinal ulceration and bleeding. Some of these effects may occur secondary to significant changes in the jejunal microbiota induced by both naproxen and PPIs.

NSAID enteropathy and bacteria: a complicated relationship

The clinical significance of small intestinal damage caused by nonsteroidal anti-inflammatory drugs (NSAIDs) remains under-appreciated. It occurs with greater frequency than the damage caused by these drugs in the upper gastrointestinal tract, but is much more difficult to diagnose and treat. Although the pathogenesis of NSAID enteropathy remains incompletely understood, it is clear that bacteria, bile, and the enterohepatic circulation of NSAIDs are all important factors. However, they are also interrelated with one another. Bacterial enzymes can affect the cytotoxicity of bile and are essential for enterohepatic circulation of NSAIDs. Gram-negative bacteria appear to be particularly important in the pathogenesis of NSAID enteropathy, possibly through release of endotoxin. Inhibitors of gastric acid secretion significantly aggravate NSAID enteropathy, and this effect is due to significant changes in the intestinal microbiome. Treatment with antibiotics can, in some circumstances, reduce the severity of NSAID enteropathy, but published results are inconsistent. Specific antibiotic-induced changes in the microbiota have not been causally linked to prevention of intestinal damage. Treatment with probiotics, particularly Bifidobacterium, Lactobacillus, and Faecalibacteriaum prausnitzii, has shown promising effects in animal models. Our studies suggest that these beneficial effects are due to colonization by the bacteria, rather than to products released by the bacteria.

Improved in vitro assay for determining the mucin adherence of bacteria sensitive to Triton X-100 treatment

Mucin-associated microbiota are in relatively close contact with the intestinal epithelium and may thus have a more pronounced effect on host health. We have previously developed a simple mucin agar assay to simulate initial mucus colonization by intestinal microbial communities. Adherence of microbiota was estimated using flow cytometry after detachment with Triton X-100. In this study, the effect of this detergent on the cultivability of both virulent and commensal strains was investigated. Mucin attachment of selected strains was evaluated using the mucin adhesion assay. Bacteria were dislodged from the mucin surface by incubation with Triton or from the whole mucin agar layer using a stomacher. Mechanical extraction resulted in 1.24 ± 0.42, 2.69 ± 0.44, and 1.56 ± 0.85 log CFU/mL higher plate counts of Lactobacillus rhamnosus, Bacillus cereus, and Escherichia coli strains, respectively, than the chemical method. The sensitivity of bacteria to Triton varied among microbial species and strains. Among others, Triton inhibited the growth of Salmonella enterica LMG 10396 and Pseudomonas aeruginosa LMG 8029 on laboratory media, although these bacteria maintained their viability during this treatment. Only Gram-positive strains, Enterococcus hirae LMG 6399 and L. rhamnosus GG, were not affected by this detergent. Therefore, the mechanical method is recommended for the extraction of mucin-adhered bacteria that are sensitive to Triton, especially when followed by traditional cultivation techniques. However, this approach can also be recommended for strains that are not affected by this detergent, because it resulted in higher recovery of adhered L. rhamnosus GG compared to the chemical extraction.

Hydrogen sulphide protects against NSAID-enteropathy through modulation of bile and the microbiota

BACKGROUND AND PURPOSE

Hydrogen sulphide is an important mediator of gastrointestinal mucosal defence. The use of non-steroidal anti-inflammatory drugs (NSAIDs) is significantly limited by their toxicity in the gastrointestinal tract. Particularly concerning is the lack of effective preventative or curative treatments for NSAID-induced intestinal damage and bleeding. We evaluated the ability of a hydrogen sulphide donor to protect against NSAID-induced enteropathy.

EXPERIMENTAL APPROACH

Intestinal ulceration and bleeding were induced in Wistar rats by oral administration of naproxen. The effects of suppression of endogenous hydrogen sulphide synthesis or administration of a hydrogen sulphide donor (diallyl disulphide) on naproxen-induced enteropathy was examined. Effects of diallyl disulphide on small intestinal inflammation and intestinal microbiota were also assessed. Bile collected after in vivo naproxen and diallyl disulphide administration was evaluated for cytotoxicity in vitro using cultured intestinal epithelial cells.

KEY RESULTS

Suppression of endogenous hydrogen sulphide synthesis by β-cyano-L-alanine exacerbated naproxen-induced enteropathy. Diallyl disulphide co-administration dose-dependently reduced the severity of naproxen-induced small intestinal damage, inflammation and bleeding. Diallyl disulphide administration attenuated naproxen-induced increases in the cytotoxicity of bile on cultured enterocytes, and prevented or reversed naproxen-induced changes in the intestinal microbiota.

CONCLUSIONS AND IMPLICATIONS

Hydrogen sulphide protects against NSAID-enteropathy in rats, in part reducing the cytotoxicity of bile and preventing NSAID-induced dysbiosis.

The protective effect of aged garlic extract on nonsteroidal anti-inflammatory drug-induced gastric inflammations in male albino rats

Natural products have long gained wide acceptance among the public and scientific community in the gastrointestinal ulcerative field. The present study explore the potential effects of aged garlic extract (AGE) on indomethacin-(IN-) induced gastric inflammation in male rats. Animals were divided into six groups (n = 8) control group, IN-induced gastric inflammation group via oral single dose (30 mg/kg to fasted rats) two AGE orally administered groups (100 and 200 mg/kg for 30 consecutive days) two AGE orally administered groups to rats pretreated with IN at the same aforementioned doses. The results declared the more potent effect of the higher AGE dose (200 mg/kg) as compared to that of the 100 mg/kg dose in the gastroprotective effects reflected by significant gastric mucosal healing of damage and reduction in the total microbial induced due to indomethacin administration. In addition to the significant effect to normalize the significant increase in malondialdehyde (MDA), myeloperoxidase (MPO), tumor necrosis factor-α (TNF-α) values, and the significant decrease in the total glutathione (tGSH), superoxide dismutase (SOD), and catalase (CAT) values induced by indomethacin. The results support AGE antioxidant, anti-inflammatory, and antimicrobial potency reflected by the healing of the gastric tissue damage induced by indomethacin.

ImproWin® in the treatment of gastric ulceration of the squamous mucosa in trotting racehorses

BACKGROUND

Gastric ulceration is highly prevalent in horses, and there is a large commercial market for feed-additives and non-licenced products that claim effect for prevention and treatment of gastric ulceration. ImproWin® has been used as a feed additive in horses with anecdotal evidence that it may have some positive effects on gastric ulceration.The aim of this study was to investigate the effect of ImproWin® treatment on spontaneously occurring gastric ulcers of the squamous mucosa in Standardbred and Coldblooded trotting racehorses. The study was performed as a randomised, double-blinded, single centre study with stratified semi cross-over design with breed as stratification factors. The horses were clinically and endoscopically examined prior to start and after three weeks of treatment. The ulcerations were scored in accordance with Equine Gastric Ulcer Council (EGUC) recommendations on a 5 point scale and on a 10 cm Visual Analogue Scale (VAS). The patients were responder-classified after 3 weeks. Responders in need of ulcer treatment were randomly allocated to 2 or 4 weeks of additional treatment. Non-responders to placebo were crossed to ImproWin®.

RESULTS

The 5-point EGUC score and VAS recorded score was significantly reduced (P ≤ 0.01) in both groups after 3 weeks of treatment. From 3 weeks to the end of treatment the score was further significantly reduced in the ImproWin® group (P ≤ 0.05). At the end of treatment, 78% in the ImproWin® group and 54.8% in the placebo group were classified as responders. The difference was significant (P = 0.04).

CONCLUSIONS

ImproWin® may aid the healing process of ulcers of the gastric squamous mucosa of trotters.

The probiotic mixture VSL#3 accelerates gastric ulcer healing by stimulating vascular endothelial growth factor

Studies assessing the effect and mechanism of probiotics on diseases of the upper gastrointestinal tract (GI) including gastric ulcers are limited despite extensive work and promising results of this therapeutic option for other GI diseases. In this study, we investigated the mechanisms by which the probiotic mixture VSL#3 (a mixture of eight probiotic bacteria including Lactobacilli, Bifidobacteria and Streptococcus species) heals acetic acid induced gastric ulcer in rats. VSL#3 was administered orally at low (6×10⁹ bacteria) or high (1.2×10¹⁰ bacteria) dosages from day 3 after ulcer induction for 14 consecutive days. VSL#3 treatments significantly enhanced gastric ulcer healing in a dose-dependent manner. To assess the mechanism(s) whereby VSL#3 exerted its protective effects, we quantified the gene expression of several pro-inflammatory cytokines, protein and expression of stomach mucin-Muc5ac, regulatory cytokine-IL-10, COX-2 and various growth factors. Of all the components examined, only expression and protein production of VEGF was increased 332-fold on day 7 in the ulcerated tissues of animals treated with VSL#3. Predictably, animals treated with VEGF neutralizing antibody significantly delayed gastric ulcer healing in VSL#3 treated animals. This is the first report to demonstrate high efficacy of the probiotic mixture VSL#3 in enhancing gastric ulcer healing. Probiotic efficacy was effective at higher concentrations of VSL#3 by specifically increasing the expression and production of angiogenesis promoting growth factors, primarily VEGF.

Restoring psychology's role in peptic ulcer

This paper reviews the history of the transition from the belief that gastrointestinal ulcers are caused primarily by psychological factors to the current state of belief that they are caused primarily by infection and argues that neither is fully accurate. We argue that psychological factors play a significant role as predisposing to vulnerability, modulating of precipitation, and sustaining of gastric ulceration. We review data that challenge the assumption of a simple infectious disease model and adduce recent preclinical data that confirm the predisposing, modulatory, and sustaining roles for psychological factors. We note that others, too, are now challenging the adequacy of the contemporary simple bacterial infection model. We hope to replace the competition between psychology and medicine with cooperation in understanding and treating patients suffering gastric ulceration and ulcer.

Gastrointestinal-sparing effects of novel NSAIDs in rats with compromised mucosal defence

Nonsteroidal anti-inflammatory drugs are among the most commonly used prescription and over-the-counter medications, but they often produce significant gastrointestinal ulceration and bleeding, particularly in elderly patients and patients with certain co-morbidities. Novel anti-inflammatory drugs are seldom tested in animal models that mimic the high risk human users, leading to an underestimate of the true toxicity of the drugs. In the present study we examined the effects of two novel NSAIDs and two commonly used NSAIDs in models in which mucosal defence was expected to be impaired. Naproxen, celecoxib, ATB-346 (a hydrogen sulfide- and naproxen-releasing compound) and NCX 429 (a nitric oxide- and naproxen-releasing compound) were evaluated in healthy, arthritic, obese, and hypertensive rats and in rats of advanced age (19 months) and rats co-administered low-dose aspirin and/or omeprazole. In all models except hypertension, greater gastric and/or intestinal damage was observed when naproxen was administered in these models than in healthy rats. Celecoxib-induced damage was significantly increased when co-administered with low-dose aspirin and/or omeprazole. In contrast, ATB-346 and NCX 429, when tested at doses that were as effective as naproxen and celecoxib in reducing inflammation and inhibiting cyclooxygenase activity, did not produce significant gastric or intestinal damage in any of the models. These results demonstrate that animal models of human co-morbidities display the same increased susceptibility to NSAID-induced gastrointestinal damage as observed in humans. Moreover, two novel NSAIDs that release mediators of mucosal defence (hydrogen sulfide and nitric oxide) do not induce significant gastrointestinal damage in these models of impaired mucosal defence.

Role of activation of 5'-adenosine monophosphate-activated protein kinase in gastric ulcer healing in diabetic rats

BACKGROUND

The potential utility of 5'-adenosine monophosphate-activated protein kinase (AMPK)-activating agents, such as metformin, in inducing angiogenesis, could be a promising approach to promote healing of gastric ulcers complicated by diabetes mellitus. The aim of the present study was to assess the effect of a drug that activates AMPK, namely metformin, in gastric ulcer healing in streptozotocin-induced diabetic rats.

METHODS

Forty male Wistar albino rats were made diabetic by intraperitoneal (i.p.) streptozotocin injection and 10 rats were injected i.p. by a single dose of physiological saline. Six weeks following streptozotocin or saline injection, gastric ulcers were induced by serosal application of acetic acid. Three days after acetic acid application, rats were divided into group 1 (nondiabetic control), group 2 (streptozotocin-injected rats), groups 3-5 (streptozotocin-injected rats treated with metformin or metformin and an inhibitor of AMPK, namely compound C or pioglitazone) for 7 days following acetic acid application.

RESULTS

Administration of metformin, but not pioglitazone, resulted in a significant decrease in the gastric ulcer area, a significant increase in epithelial regeneration assessed histologically, a significant increase in the number of microvessels in the ulcer margin, a significant increase in gastric vascular endothelial growth factor concentration and gastric von Willebrand factor as well as a significant increase in gastric phospho-AMPK. Compound C, an inhibitor of AMPK, blocked metformin-induced changes in assessed parameters suggesting that the effect of metformin was mediated mainly through activation of AMPK.

CONCLUSION

Our results suggest the feasibility of a novel treatment strategy, namely drugs activating AMPK, for patients in whom impairment of ulcer healing constitutes a secondary complication of diabetes mellitus.

Muc-2-deficient mice display a sex-specific, COX-2-related impairment of gastric mucosal repair

Mucus is known to contribute significantly to the prevention and repair of mucosal damage throughout the gastrointestinal tract. Although not normally expressed in the stomach, mucin-2 (MUC-2, encoded by the MUC2 gene) is expressed in certain disease states. The aim of this study was to determine in a mouse model whether the absence of Muc-2 would result in impaired susceptibility to and healing of gastric mucosal injury. Acute gastric damage was induced in mice deficient in Muc-2 and in wild-type controls, through oral administration of indomethacin. Chronic gastric ulcers were induced by serosal application of acetic acid. The extent of injury and the extent of healing of the damage over time were examined in both models. Indomethacin administration caused similar levels of gastric damage in Muc-2-deficient and wild-type mice, but the erosions healed more slowly in the former. Acetic acid-induced gastric ulcers were initially similar in size in Muc-2-deficient and wild-type mice of both sexes, but ulcer healing was significantly impaired in male Muc-2-deficient mice. Induction of cyclooxygenase-2 in the stomach, in response to indomethacin- or acetic acid-induced ulceration, was significantly reduced in male Muc-2-deficient mice. This phenomenon, and the sex specificity, was also apparent in bone marrow-derived macrophages stimulated with endotoxin. These results demonstrate a marked impairment of gastric mucosal repair in male Muc-2-deficient mice that may be related to an insufficient induction of cyclooxygenase-2, an enzyme known to contribute to mucosal repair.

Novel probiotic Bifidobacterium bifidum CECT 7366 strain active against the pathogenic bacterium Helicobacter pylori

Helicobacter pylori is considered one of the major risk factors underlying the development of gastritis and gastric and duodenal ulcers. Moreover, 50% of the population carries this bacterium, and consequently, when it is detected, eradication of H. pylori is strongly recommended. Regarding the use of probiotics as functional agents, several studies have shown that there is a direct relationship between the addition of certain probiotic bacteria and in vitro inhibition of H. pylori; however, in vivo studies showing bifidobacterial activity against H. pylori remain scarce. In this study, a Bifidobacterium bifidum strain which proved active in vitro against H. pylori has been isolated, with inhibition levels reaching 81.94% in the case of the supernatant and even 94.77% inhibition for supernatant purified by cationic exchange followed by an inverse phase. In vivo studies using a BALB/c mouse model have proved that this strain partially relieves damage to gastric tissues caused by the pathogen and also decreases the H. pylori pathogenicity ratio. This novel strain fulfills the main properties required of a probiotic (resistance to gastrointestinal juices, biliary salts, NaCl, and low pH; adhesion to intestinal mucus; and sensitivity to antibiotics). Furthermore, the absence of undesirable metabolites has been demonstrated, and its food safety status has been confirmed by acute ingestion studies in mice. In summary, the results presented here demonstrate that Bifidobacterium bifidum CECT 7366 can be considered a probiotic able to inhibit H. pylori both in vitro and in vivo.

Antibacterial and ulcer healing effects of organoselenium compounds in naproxen induced and Helicobacter pylori infected Wistar rat model

Aim of the present study was to evaluate in vitro toxicity and in vivo antibacterial, anti-inflammatory, antiulcer, and antioxidant activities of two organoselenium compounds, selenocystine (SeCys) and ebselen (Ebs). The study was conducted in experimentally induced ulcers in rodent model infected with Helicobacter pylori (H. pylori). In vitro toxicological studies on normal splenic lymphocytes revealed that SeCys and Ebs were non-toxic to the cells even at 100 μM concentration. Antibacterial activity was observed at 500 μg/mL concentration of either of the compounds against H. pylori. In vivo studies after treatment with SeCys and Ebs (500 μg/kg/day) resulted in significant reduction in ROS production and inhibition of lipid peroxidation in gastric tissue. The antioxidant and anti-inflammatory activities of both the compounds were also confirmed by their ability to lower GSH reduction, to induce the expression of antioxidant genes such as GPx-4, and MnSOD and to suppress inflammatory genes namely COX-2, TNF-α and TGF-β. In addition, the immunomodulatory activity of both the compounds was evident by enhance of the CD4 levels and maintenance of the IgG, IL-6 and IL-10 levels. Persistent treatment (500 μg/kg, for 28 days) with both the compounds showed considerable (p<0.05) ulcer healing property supporting its role in gastro protection. In conclusion, the results of our study suggest that both SeCys and Ebs possess broad spectrum of activities without any potential toxicity.

Yogurt containing Lactobacillus gasseri OLL 2716 (LG21 yogurt) accelerated the healing of acetic acid-induced gastric ulcer in rats

We have reported that LG21 yogurt containing Lactobacillus gasseri OLL 2716 (LG21 yogurt) inhibits the formation of HCl-induced acute gastric lesions through the generation of prostaglandin E₂. This study aimed to determine the role of viable Lactobacillus in the healing of acetic acid-induced chronic gastric ulcer. LG21 yogurt or γ-ray radiated LG21 yogurt was administered orally twice a day for 10 d at a dose of 5 ml/kg. LG21 yogurt significantly accelerated the healing of the ulcer, but γ-ray radiated LG21 yogurt did not. However, both yogurts significantly inhibited HCl-induced gastric erosive lesions and enhanced the generation of gastric mucosal prostaglandin E₂. From the above results, it was found that viable bacteria are needed to accelerate the healing of chronic gastric ulcer, but not to inhibit gastric lesions.

Recombinant Human Epidermal Growth Factor Alleviates Gastric Antral Ulcer Induced by Naproxen: A Non-steroidal Anti Inflammatory Drug

BACKGROUND

To study the effect (s) of recombinant human Epidermal Growth Factor (rhEGF) on naproxen induced gastric ulcer in Wistar NIN rats.

METHODS

Male Wistar NIN rats were randomly divided into six experimental groups: Group I - Control, Group II - Naproxen treated, Group III - Naproxen with rhEGF/7 days, Group IV - Naproxen without rhEGF/7 days, Group V - Naproxen with rhEGF/14 days, and Group VI - Naproxen without rhEGF/14 days. Gastric ulcer was induced with naproxen at a concentration of 80 mg/kg by oral administration. After 24 hours of induction of ulcer, rhEGF treatment was started at a concentration of 100 µg/kg. Ulcer presence and healing were confirmed by histopathology study and molecular markers.

RESULTS

Naproxen per se induced gastric antral ulcers in Wistar NIN rats. Compared with control rats, naproxen induced rats had increased lipid peroxide content in serum. Subsequent decrease in lipid peroxide was observed in rhEGF treated groups. Treatment with rhEGF significantly resulted in healing of the ulcers, which was evident by 7 days of rhEGF treatment with total healing seen by 14 days. Significant increase in immunoreactivity for Cox-2 was observed when compared to control groups, whereas less immunoreactivity of Cox-2 was observed in rhEGF treated group. Compared with control group, naproxen induced group exhibited more gene expression of both Cox-2 and TGF beta while gene expression of Cox-2 and TGF beta in rhEGF group was comparable to control group.

CONCLUSIONS

The beneficial effects of rhEGF in the management of ulcer healing can be understood. Oral rhEGF can promote healing of the rats with gastric ulcer by stimulating Cox-2 and TGF-beta expression.

Live and heat-inactivated lactobacilli from feces inhibit Salmonella typhi and Escherichia coli adherence to Caco-2 cells

A quantitative approach has been proposed to evaluate the competitive inhibition of Escherichia coli and Salmonella typhi by live and heat-inactivated laboratory isolated Lactobacillus sp. on adhesion to monolayer of Caco-2 cells. Three species of Lactobacillus (L. casei, L. acidophilus, L. agilis) isolated from human neonate feces and two commercial probiotic strains (L. casei, L. acidophilus) have been compared for probiotic activity. All lactobacilli were able to attach to the Caco-2 cells, however, the degree of adhesion was bacterial strain-dependent. The adhesion indices of the two commercial probiotic strains were not significantly different from the values obtained for the other two similar fecal strains (p > 0.01). The inhibition of attachment of the pathogenic bacteria by inactivated cells of fecal L. acidophilus was examined and compared to the results of live bacteria. The inhibition pattern was similar for live and heat-inactivated L. acidophilus (p > 0.01). The number of attached pathogenic bacteria to the Caco-2 cells decreased when the number of L. acidophilus increased from 10(6) to 10(9) CFU/mL. The heat-inactivated L. acidophilus displayed similar probiotic activity compared to the live bacteria.

Lactobacilli and enterococci--potential probiotics for dogs

Forty strains of enterococci and forty strains of lactobacilli isolated from feces of 10 healthy dogs were tested for the antimicrobial activity, tolerance to bile and adhesion activity. The total count of fecal enterococci reached 5.5 log CFU/g and of lactobacilli 7.6 log CFU/g. Screening for production of bacteriocin-like substances showed an to partly inhibit the growth of Enterobacter sp. (hazy zones of inhibition). Ten strains of Enterococcus sp. and nine strains of Lactobacillus sp. were found without any inhibitory activity against all indicators used. Seven enterococcal strains and six lactobacilli with the broadest antimicrobial spectrum were selected for further probiotic assays. In the presence of 1% bile, the survival rate of selected enterococci (71.7-97.5%) was higher than that of lactobacilli (66.7-75.4%). The adhesion of strains to human intestinal mucus (5.1-8.2% by enterococci, 2.7-8.3% by lactobacilli) was found to be similar as adhesion to canine intestinal mucus (3.7-10.6% by enterococci, 2.1-6.0% by lactobacilli). Strain AD1, one lactobacillus isolate, reduced the higher level of serum cholesterol and alanine aminotransferase after oral administration to dogs suffering from diseases of the gastrointestinal tract.

Disease-dependent adhesion of lactic acid bacteria to the human intestinal mucosa

Their adhesion to the intestinal mucosa is considered one of the main reasons for the beneficial health effects of specific lactic acid bacteria (LAB). However, the influence of disease on the mucosal adhesion is largely unknown. Adhesion of selected LAB to resected colonic tissue and mucus was determined in patients with three major intestinal diseases (i.e., diverticulitis, rectal carcinoma, and inflammatory bowel disease) and compared to healthy control tissue. All strains were observed to adhere better to immobilized mucus than to whole intestinal tissue. Two strains (Lactobacillus rhamnosus strain GG and L. reuteri) were found to exhibit disease-specific adhesion to intestinal tissue. All tested strains, with the exception of L. rhamnosus strain GG, displayed disease-specific adhesion to intestinal mucus. These results suggest that strains with optimal binding characteristics for a particular intestinal disease can be selected.

Gastritis and hypergastrinemia due to Acinetobacter lwoffii in mice

In mouse models and humans, Helicobacter pylori is associated with an increase in serum gastrin and gastrin-expressing (G) cells with a concomitant decrease in somatostatin-expressing D cells. Inflammation of the gastric mucosa can progress to metaplastic changes in the stomach and to decreased colonization by H. pylori and increased colonization by non-H. pylori organisms. In addition, about 20% of individuals with chronic gastritis are H. pylori negative, suggesting that other organisms may induce gastritis. Consistent with this hypothesis, we report here that Acinetobacter lwoffii causes the same histologic changes as does H. pylori. Gastric epithelial cells were isolated from the entire stomach by an enzymatic method for quantitation by both flow cytometry and morphometric analysis. Two months after mice were inoculated with H. pylori or A. lwoffii, the mucosal T- and B-cell numbers significantly increased. After 4 months of infection, there was a threefold increase in the number of G cells and a doubling in the number of parietal cells. A threefold decrease in the number of D cells occurred in H. pylori- and A. lwoffii-infected mice. Plasma gastrin levels increased after both H. pylori and A. lwoffii infection. Histology revealed the presence of inflammation in the gastric mucosa with both A. lwoffii and H. pylori infection. A periodic acid-Schiff stain-alcian blue stain revealed mucous gland metaplasia of the corpus. Collectively, the results demonstrate that gastritis and hypergastrinemia are not specific for H. pylori but can be induced by other gram-negative bacteria capable of infecting the mouse stomach.

Gastritis and hypergastrinemia due to Acinetobacter lwoffii in mice

In mouse models and humans, Helicobacter pylori is associated with an increase in serum gastrin and gastrin-expressing (G) cells with a concomitant decrease in somatostatin-expressing D cells. Inflammation of the gastric mucosa can progress to metaplastic changes in the stomach and to decreased colonization by H. pylori and increased colonization by non-H. pylori organisms. In addition, about 20% of individuals with chronic gastritis are H. pylori negative, suggesting that other organisms may induce gastritis. Consistent with this hypothesis, we report here that Acinetobacter lwoffii causes the same histologic changes as does H. pylori. Gastric epithelial cells were isolated from the entire stomach by an enzymatic method for quantitation by both flow cytometry and morphometric analysis. Two months after mice were inoculated with H. pylori or A. lwoffii, the mucosal T- and B-cell numbers significantly increased. After 4 months of infection, there was a threefold increase in the number of G cells and a doubling in the number of parietal cells. A threefold decrease in the number of D cells occurred in H. pylori- and A. lwoffii-infected mice. Plasma gastrin levels increased after both H. pylori and A. lwoffii infection. Histology revealed the presence of inflammation in the gastric mucosa with both A. lwoffii and H. pylori infection. A periodic acid-Schiff stain-alcian blue stain revealed mucous gland metaplasia of the corpus. Collectively, the results demonstrate that gastritis and hypergastrinemia are not specific for H. pylori but can be induced by other gram-negative bacteria capable of infecting the mouse stomach.

Is there a role for psychology in ulcer disease?

The discovery of the importance of bacterial factors in the etiology of ulcer disease has led to a neglect of psychological factors. However, both earlier theoretical and empirical approaches implicating these factors are supported by more recent studies, both epidemiological and experimental. While not ignoring the unquestioned role of Helicobacter, it is important for future research to recognize the multi-factorial nature of ulcer disease by which several factors, including stress, bacteria and non-steroid antiinflammatory drugs, may interact to drive a pre-pathology (erosions or ulcerations) to a pathological state (ulcer). Calls for general eradication programs should be cautioned in the light of possible unwanted side effects.

NSAID-induced gastric damage in rats: requirement for inhibition of both cyclooxygenase 1 and 2

BACKGROUND & AIMS

Selective cyclooxygenase (COX)-2 inhibitors produce less gastric damage than conventional nonsteroidal anti-inflammatory drugs (NSAIDs), suggesting that NSAIDs cause damage by inhibiting COX-1. We tested this hypothesis in rats by using a selective COX-1 inhibitor (SC-560).

METHODS

The effects of SC-560, celecoxib (selective COX-2 inhibitor), or a combination of both inhibitors on gastric damage and prostaglandin synthesis were determined. Selectivity of the drugs for COX-1 vs. COX-2 was assessed in the carrageenan-airpouch model. A COX-1-preferential inhibitor, ketorolac, was also evaluated. The effects of these inhibitors on leukocyte adherence to vascular endothelium and on gastric blood flow were assessed.

RESULTS

SC-560 markedly reduced gastric prostaglandin synthesis and platelet COX-1 activity, but spared COX-2 and did not cause gastric damage. Celecoxib did not affect gastric prostaglandin E(2) synthesis and did not cause gastric damage. However, the combination of SC-560 and celecoxib invariably caused hemorrhagic erosion formation, comparable to that seen with indomethacin. Ketorolac caused damage only at doses that inhibited both COX isoforms, or when given with a COX-2 inhibitor. Celecoxib, but not SC-560, significantly increased leukocyte adherence, whereas SC-560, but not celecoxib, reduced gastric blood flow.

CONCLUSIONS

Inhibition of both COX-1 and COX-2 is required for NSAID-induced gastric injury in the rat.

Treatment of gastric ulcers and diarrhea with the Amazonian herbal medicine sangre de grado

Sangre de grado is an Amazonian herbal medicine used to facilitate the healing of gastric ulcers and to treat gastritis, diarrhea, skin lesions, and insect stings. This study was designed to evaluate the gastrointestinal applications. Gastric ulcers were induced in rats by brief serosal exposure of the fundus to acetic acid (80%). Sangre de grado was administered in drinking water at 1:1,000 and 1:10,000 dilutions from the postoperative period to day 7. Guinea pig ileum secretory responses to capsaicin, electrical field stimulation, and the neurokinin-1 (NK-1) agonist [Sar(9),Met(O(2))(11)]substance P were examined in Ussing chambers. Sangre de grado facilitated the healing of experimental gastric ulcer, reducing myeloperoxidase activity, ulcer size, and bacterial content of the ulcer. The expression of proinflammatory genes tumor necrosis factor-alpha, inducible nitric oxide synthase (iNOS), interleukin (IL)-1beta, IL-6, and cyclooxygenase-2 was upregulated by ulcer induction but reduced by sangre de grado treatment, particularly iNOS and IL-6. In Ussing chambers, sangre de grado impaired the secretory response to capsaicin but not to electrical field stimulation or the NK-1 agonist. We conclude that sangre de grado is a potent, cost-effective treatment for gastrointestinal ulcers and distress via antimicrobial, anti-inflammatory, and sensory afferent-dependent actions.

Wound collagen deposition in rats: effects of an NO-NSAID and a selective COX-2 inhibitor

Selective cyclo-oxygenase (COX)-2 inhibitors and nitric oxide-releasing nonsteroidal anti-inflammatory drugs (NSAIDs) exhibit reduced toxicity in the gastrointestinal tract, but may affect wound healing in other tissues. In this study, we have compared the effects of a selective COX-2 inhibitor (celecoxib), a nitric-oxide releasing derivative of naproxen (HCT-3012) and naproxen in a model of wound collagen deposition in the rat. Polyvinyl alcohol sponges were implanted subcutaneously in rats. The rats were treated daily for 5 days with the test drugs at equieffective anti-inflammatory doses. Naproxen (10 mg kg(-1)) significantly decreased (45%) collagen deposition at the wound site relative to the vehicle-treated control group. In contrast, HCT-3012 (14.5 mg kg(-1)) significantly increased (62%) collagen deposition, while celecoxib (10 mg kg(-1)) had no effect. Naproxen and HCT-3012 suppressed prostaglandin (PG) E(2) levels at the wound site and whole blood thromboxane synthesis to similar degrees. Celecoxib had no significant effect on wound fluid PGE(2) levels, but slightly reduced whole blood thromboxane synthesis (by 17%). COX-1 mRNA and protein were expressed in the wound exudate, the skin surrounding the wound and in normal skin. In contrast, COX-2 mRNA, but not protein, was expressed in wound and normal skin. These results demonstrate that HCT-3012 can significantly enhance collagen deposition at a wound site, despite inhibiting prostaglandin synthesis to the same extent as the parent drug. Nitric oxide-releasing NSAIDs may represent a safer alternative to standard NSAIDs for use as anti-inflammatory and analgesic agents by post-surgery patients.

Bacterial colonization and healing of gastric ulcers: the effects of epidermal growth factor

Experimental gastric ulcers are rapidly colonized by various bacteria, resulting in significantly impaired healing. Epidermal growth factor (EGF) is capable of preventing bacterial colonization of the healthy intestinal mucosa. In this study, we examined the possibility that EGF accelerates gastric ulcer healing by reducing bacterial colonization of the ulcer. Gastric ulcers were induced by serosal application of acetic acid. The effect of daily administration of EGF on ulcer healing and bacterial colonization was assessed and compared with the effect of daily treatment with broad-spectrum antibiotics. EGF administration reduced colonization levels and accelerated ulcer healing as effectively as the antibiotic treatment. EGF was without effect on acid secretion or neutrophil infiltration into the ulcer. Bacterial growth was not inhibited in the presence of EGF in vitro. These results demonstrate that EGF reduces bacterial colonization during an established infection of a compromised mucosal surface. This effect may contribute to the ability of EGF to accelerate gastric ulcer healing. This effect is acid independent and not due to an anti-inflammatory effect or to direct bactericidal actions.