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Abstracts

LE Magazine December 2006
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Zinc-Carnosine

Novel therapeutic approaches to gastric and duodenal ulcers: an update.

Over the last 25 years, a remarkable revolution in the pathophysiology and treatment of gastric and duodenal ulcers has occurred. Effective therapies were developed not only to heal ulcers, but also to cure most patients. The two principal causes for gastric and duodenal ulcers are either infection with Helicobacter pylori or the use of non-steroidal anti-inflammatory drugs (NSAIDs). With H. pylori eradication, gastric and duodenal ulcers are rapidly becoming historical diseases. This communication reviews the salient pharmacology of the novel anti-ulcer drugs currently in development, with particular emphasis on the treatment of gastric and duodenal ulcers. Intense research is currently focused on the development of proton pump inhibitors primarily for the treatment and prevention of gastroesophageal reflux disease. The older proton pump inhibitors, omeprazole and lansoprazole, are effective in healing gastric and duodenal ulcers. Furthermore, both drugs are effective in eradicating H. pylori when given with various antibiotics. Pantoprazole, rabeprazole and esomeprazole are new proton pump inhibitors, which appear to have comparable therapeutic profiles with omeprazole and lansoprazole. Rebamipide is a new mucosal protective drug, which is effective in healing gastric ulcers. Polaprezinc and nocloprost are also mucosal protective drugs, which are in clinical development. However, none of these three cytoprotective drugs have been evaluated for their efficacy in eradicating H. pylori when given in combination with antibiotics. Likewise, no published literature exists on the use of these drugs for preventing NSAID-induced ulcers. With the rapid eradication of H. pylori currently happening in the developed world, the therapeutic challenge is now directed toward preventing NSAID-associated ulcer. Significant reduction of NSAID-induced ulcers is achieved by using continuous prophylactic anti-ulcer therapy (misoprostol or omeprazole) or by using NSAIDs possessing selective COX-2 inhibitory activity. However, outcome clinical studies are needed to compare the adjuvant anti-ulcer therapies given with COX-1 inhibitors versus the selective COX-2 inhibitors given alone.

Expert Opin Investig Drugs. 2000 Jul;9(7):1537-44

Pathogenesis of Helicobacter pylori infection.

Helicobacter pylori is the first formally recognized bacterial carcinogen and is one of the most successful human pathogens, as over half of the world’s population is colonized with this gram-negative bacterium. Unless treated, colonization usually persists lifelong. H. pylori infection represents a key factor in the etiology of various gastrointestinal diseases, ranging from chronic active gastritis without clinical symptoms to peptic ulceration, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Disease outcome is the result of the complex interplay between the host and the bacterium. Host immune gene polymorphisms and gastric acid secretion largely determine the bacterium’s ability to colonize a specific gastric niche. Bacterial virulence factors such as the cytotoxin-associated gene pathogenicity island-encoded protein CagA and the vacuolating cytotoxin VacA aid in this colonization of the gastric mucosa and subsequently seem to modulate the host’s immune system. This review focuses on the microbiological, clinical, immunological, and biochemical aspects of the pathogenesis of H. pylori.

Clin Microbiol Rev. 2006 Jul;19(3):449-90

Zinc carnosine, a health food supplement that stabilises small bowel integrity and stimulates gut repair processes.

BACKGROUND: Zinc carnosine (ZnC), is a health food product claimed to possess health-promoting and gastrointestinal supportive activity. Scientific evidence underlying these claims is, however, limited. We, therefore, examined the effect of ZnC on various models of gut injury and repair and in a clinical trial. METHODS: In vitro studies utilised pro-migratory (wounded monolayer) and proliferation ([3H] thymidine incorporation) assays of human colonic (HT29), rat intestinal (RIE) and canine kidney (MDCK) epithelial cells. In vivo studies utilised rat gastric (indomethacin/restraint) and mouse small intestinal (indomethacin) damage models. Healthy volunteers (n=10) undertook a randomised cross-over trial comparing changes in gut permeability (lactulose/rhamnose ratios, L/R) before and after 5 days of indomethacin (50 mg tds, po.) with ZnC (37.5 mg bd) or placebo co-administration. RESULTS: ZnC stimulated migration and proliferation in a dose-dependent manner (maximum effects in both assays at 100microM using HT29 cells), causing an approximate three fold increase in migration or proliferation (both p < 0.01). Oral ZnC decreased gastric (75% reduction at 5mg/ml) and small intestinal injury (50% reduction in villus shortening at 40 mg/ml), both p< 0.01. In volunteers, indomethacin caused a three- fold increase in gut permeability in the control arm; L/R ratio 0.35 +/- 0.035 prior to indomethacin and 0.88 +/- 0.11 (mean +/- SEM) after 5 days indomethacin (p < 0.01), whereas no significant increase in permeability was seen when ZnC was co-administered. CONCLUSION: These initial studies suggest that ZnC, at concentrations likely to be found in the gut lumen, stabilises gut mucosa. Further studies appear warranted.

Gut. 2006 Jun 15

Anti-inflammatory effect of roasted licorice extracts on lipopolysaccharide-induced inflammatory responses in murine macrophages.

Licorice, the roots of Glycyrrhiza inflata, is used by practitioners of alternative medicine to treat individuals with gastric or duodenal ulcers, bronchitis, cough, arthritis, adrenal insufficiency, and allergies. We investigated the anti-inflammatory properties of 4 licorice extracts: extracts of roasted licorice obtained by ethanol (rLE) or water extraction (rLW) and extracts of raw licorice obtained by ethanol (LE) or water extraction (LW). rLE demonstrated strong anti-inflammatory activity through its ability to reduce nitric oxide and prostaglandin E(2) production in the LPS-stimulated mouse macrophage cell, RAW264.7. It also inhibited the production of pro-inflammatory cytokines and CD14 expression on the LPS-stimulated RAW264.7 cells. Further study indicated that LPS-induced degradation and phosphorylation of Ikappa-Balpha, along with DNA-binding of NF-kappaB, was significantly inhibited by rLE exposure in RAW264.7 cells. In the murine model, we found that in vivo exposure to rLE-induced an increase in the survival rate, reduced plasma levels of TNF-alpha and IL-6, and increased IL-10 production in LPS-treated mice. Collectively, these data suggest that the use of rLE may be a useful therapeutic approach to various inflammatory diseases.

Biochem Biophys Res Commun. 2006 Jul 7;345(3):1215-23

Risk and safety assessment on the consumption of Licorice root (Glycyrrhiza sp.), its extract and powder as a food ingredient, with emphasis on the pharmacology and toxicology of glycyrrhizin.

Licorice (or ‘liquorice’) is a plant of ancient origin and steeped in history. Licorice extracts and its principle component, glycyrrhizin, have extensive use in foods, tobacco and in both traditional and herbal medicine. As a result, there is a high level of use of licorice and glycyrrhizin in the US with an estimated consumption of 0.027-3.6mg glycyrrhizin/kg/day. Both products have been approved for use in foods by most national and supranational regulatory agencies. Biochemical studies indicate that glycyrrhizinates inhibit 11beta-hydroxysteroid dehydrogenase, the enzyme responsible for inactivating cortisol. As a result, the continuous, high level exposure to glycyrrhizin compounds can produce hypermineralocorticoid-like effects in both animals and humans. These effects are reversible upon withdrawal of licorice or glycyrrhizin. Other in vivo and clinical studies have reported beneficial effects of both licorice and glycyrrhizin consumption including anti-ulcer, anti-viral, and hepatoprotective responses. Various genotoxic studies have indicated that glycyrrhizin is neither teratogenic nor mutagenic, and may possess anti-genotoxic properties under certain conditions. The pharmacokinetics of glycyrrhizin have been described and show that its bioavailability is reduced when consumed as licorice; this has hampered attempts to establish clear dose-effect levels in animals and humans. Based on the in vivo and clinical evidence, we propose an acceptable daily intake of 0.015-0.229mg glycyrrhizin/kg body weight/day.

Regul Toxicol Pharmacol. 2006 Jul 31

Prevention of nonspecific bacterial cell adhesion in immunoassays by use of cranberry juice.

The ability of Vaccinum macrocarpon, the North American cranberry, to prevent bacterial adhesion has been used to advantage in the prevention of urinary tract infections and has recently been described for the prevention of adhesion of bacteria responsible for oral infections and stomach ulcers. This report documents the ability of cranberry juice to reduce nonspecific adhesion of bacteria to the borosilicate glass microscope slides used in an immunoarray biosensor format. Nonspecific binding of analytes in the array sensor leads to high background signals that cause increased detection limits and false positives. Reduction in background-to-signal ratios can be seen as the juice concentration is increased from 0 to 50% of the sample. This impact cannot be duplicated with grape, orange, apple, or white cranberry juice. Sugar content and pH have been eliminated as the agents in the juice responsible for the anti-adhesive activity.

Anal Chem. 2006 Feb 1;78(3):853-7

Inhibition of Helicobacter pylori in vitro by various berry extracts, with enhanced susceptibility to clarithromycin.

The objective of this study was to evaluate the effects of various berry extracts, with and without clarithromycin on Helicobacter pylori. Resistance to clarithromycin by H. pylori has been reported, leading to interest in alternatives/adjuncts to therapy with clarithromycin. H. pylori American type culture collection (ATCC) strain 49503 was grown, cell suspensions were made in PBS and diluted 10-fold. One hundred microL of the suspension was then incubated for 18 h with extracts of raspberry, strawberry, cranberry, elderberry, blueberry, bilberry, and OptiBerry, a blend of the six berries, at 0.25-1% concentrations. Serially diluted cell suspensions were exposed for 1 h to clarithromycin at 15 microg/ml. Ten microl of bacterial samples from the 10(-7) dilution tube were plated and incubated for 18 h and the number of colonies were counted. Growth of H. pylori was confirmed by the CLO test. All berry extracts significantly (p < 0.05) inhibited H. pylori, compared with controls, and also increased susceptibility of H. pylori to clarithromycin, with OptiBerry demonstrating maximal effects.

Mol Cell Biochem. 2004 Oct;265(1-2):19-26

Efficacy of cranberry juice on Helicobacter pylori infection: a double-blind, randomized placebo-controlled trial.

BACKGROUND: Helicobacter pylori infection is a major cause of peptic ulcer disease and gastric cancer. This study postulated that cranberry juice would be effective in the suppression of H. pylori in an endemically infected population at high risk for gastric cancer. MATERIALS AND METHODS: A prospective, randomized, double-blind, placebo-controlled trial was conducted in Linqu County of Shandong Province, China, where 189 adults aged 48.9 +/- 11.2 years (mean +/- SD) with H. pylori infection were randomly divided into two groups: cranberry juice (n = 97) and placebo (n = 92). Participants were assigned to orally receive two 250-ml juice boxes of cranberry juice or matching placebo beverage daily for 90 days. The degree of H. pylori infection was determined using the 13C-urea breath test before randomization at 35 and 90 days of intervention to assess the efficacy of cranberry juice in alleviating infection. RESULTS: A total of 189 subjects with positive 13C-urea breath test results prior to randomization completed the study. At day 35 of intervention, 14 of the 97 (14.43%) from the the cranberry juice treatment group and 5 of the 92 (5.44%) of the placebo recipients had negative 13C-urea breath test results. After 90 days, the study concluded that 14 of the 97 subjects in the cranberry juice treatment group versus 5 of the 92 in the placebo group yielded negative test results. Eleven individuals from the cranberry juice treatment group and only two from the placebo group were negative at 35 and 90 days of experiment. These results are significant (p < .05). CONCLUSIONS: Regular consumption of cranberry juice can suppress H. pylori infection in endemically afflicted populations.

Helicobacter. 2005 Apr;10(2):139-45

Enhancing health benefits of berries through phenolic antioxidant enrichment: focus on cranberry.

Emerging epidemiological evidence is increasingly pointing to the beneficial effects of fruits and vegetables in managing chronic and infectious diseases. These beneficial effects are now suggested to be due to the constituent phenolic phytochemicals having antioxidant activity. Cranberry like other fruits is also rich in phenolic phytochemicals such as phenolic acids, flavonoids and ellagic acid. Consumption of cranberry has been historically been linked to lower incidences of urinary tract infections and has now been shown to have a capacity to inhibit peptic ulcer-associated bacterium, Helicobacter pylori. Isolated compounds from cranberry have also been shown to reduce the risk of cardiovascular diseases. Recent evidence suggests the ability of phytochemical components in whole foods in being more effective in protectively supporting human health than compared to isolated individual phenolic phytochemicals. This implies that the profile of phenolic phytochemicals determines the functionality of the whole food as a result of synergistic interaction of constituent phenolic phytochemicals. Solid state bioprocessing using food grade fungi common in Asian food cultures as well as cranberry phenolic synergies through the addition of functional biphenyls such as ellagic acid and rosmarinic acid along with processed fruit extracts have helped to advance these concepts. These strategies could be further explored to enrich cranberry and cranberry products with functional phytochemicals and further improve their functionality for enhancing health benefits.

Asia Pac J Clin Nutr. 2005;14(2):120-30

Inhibition of Helicobacter pylori adhesion to human gastric mucus by a high-molecular-weight constituent of cranberry juice.

A high-molecular-weight constituent of cranberry juice has been found to inhibit the sialyllactose specific adhesion of Helicobacter pylori strains to immobilized human mucus, erythrocytes, and cultured gastric epithelial cells. Different isolates of H. pylori differ in their affinity to the cranberry juice constituent. Cranberry juice may also inhibit adhesion of bacteria to the stomach in vivo, and may prove useful for the prevention of stomach ulcer that is caused by H. pylori.

Crit Rev Food Sci Nutr. 2002;42(3 Suppl):279-84

Inhibitory effect of polaprezinc on the inflammatory response to Helicobacter pylori.

Helicobacter pylori-infected gastrointestinal mucosa is frequently infiltrated by polymorphonuclear leukocytes (PMN) and monocytes, and these invading cells have been implicated in gastrointestinal mucosal inflammation. To clarify the efficacy of polaprezinc, a chelate compound consisting of zinc and L-carnosine, against H pylori-induced inflammation including PMN infiltration, the in vitro effects of this drug on interleukin (IL)-8 production by an established gastric cancer cell line (MKN 45 cells) and on PMN-endothelial cell adhesive interactions was investigated. Polaprezinc and zinc sulphate inhibited IL-8 production by MKN 45 cells in response to stimulation with H pylori water extract (HPE) in a dose-dependent manner from 10(-7) M to 10(-5) M. In addition, the expression of CD11b and CD18 on PMN and PMN-dependent adhesion to endothelial cells elicited by HPE was inhibited by polaprezinc and zinc sulphate in a concentration-dependent manner. L-carnosine did not have any effects on IL-8 production or PMN-endothelial cell interactions. These results suggest that polaprezinc, mainly the zinc component, may inhibit H pylori-induced PMN-mediated gastric inflammation by attenuating CD11b/CD18 expression on PMN and IL-8 production from gastric epithelial cells.

Can J Gastroenterol. 2002 Nov;16(11):785-9

Polaprezinc down-regulates proinflammatory cytokine-induced nuclear factor-kappaB activation and interleukin-8 expression in gastric epithelial cells.

Gastric epithelial chemokine response is a primary factor in the induction of gastric inflammation associated with Helicobacter pylori infection. Because sustained inflammation is a risk for gastric mucosal damage, agents that down-regulate inflammatory responses may be of therapeutic significance. We examined the effect of polaprezinc, a potent antiulcer agent, on proinflammatory cytokine-induced interleukin (IL)-8 expression in gastric epithelial cells. Because IL-8 expression is regulated by the transcription factor nuclear factor-kappaB (NF-kappaB), we also examined the effect of polaprezinc on NF-kappaB activity. MKN28 cells were used as a model of gastric epithelial cells. Secreted IL-8 was quantified by IL-8 specific enzyme-linked immunosorbent assay, and IL-8 mRNA expression was examined by Northern blot analysis. NF-kappaB activity was analyzed by electrophoretic mobility shift assay. Western blot analysis with anti-phospho-IkappaB-alpha antibody was performed to assess IkappaB-alpha phosphorylation. Polaprezinc-suppressed IL-8 secretion induced by tumor necrosis factor alpha (TNF-alpha) or IL-1beta in a dose-dependent manner. IL-8 mRNA expression also was inhibited by polaprezinc. NF-kappaB activation in response to TNF-alpha, IL-1beta, phorbol ester, and H(2)O(2) was down-regulated by polaprezinc. Western blot analysis showed inhibition of TNF-alpha-induced IkappaB-alpha phosphorylation in the presence of polaprezinc. Collectively, these results suggest that polaprezinc is a novel type of anti-inflammatory agent that down-regulates inflammatory responses of gastric mucosal cells.

J Pharmacol Exp Ther. 1999 Oct;291(1):345-52

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