Oxidative stress is more important than acid in the pathogenesis of reflux oesophagitis in rats

Prevention of NSAID-associated gastroduodenal injury in healthy volunteers-a randomized, double-blind, multicenter study comparing DA-9601 with misoprostol

In addition to inhibiting cyclooxygenase and prostaglandin, nonsteroidal anti-inflammatory drugs (NSAIDs) may cause gastroduodenal injuries due to reactive oxygen species produced by recruited inflammatory cells. DA-9601 is a novel antioxidant with anti-inflammatory and cyto-protective effects. This study was conducted to compare the efficacy and safety of DA-9601 with misoprostol for preventing NSAID-associated gastroduodenal injury. In this randomized, double-blind, multicenter, noninferiority trial we compared the extents of protection of gastric and duodenal mucosae by endoscopy after 4 weeks of treatment with DA-9601 60 mg or misoprostol 200 µg three times daily, in subjects with normal baseline endoscopic findings who received an NSAID twice daily for 4 weeks. A total of 266 subjects were randomized to treatment. At week 4, the gastric protection rates with DA-9601 and misoprostol were 85.1% and 95.2%, respectively; the difference between the groups was -10.1% (var = 0.001), which was shown to indicate noninferiority of DA-9601 compared to misoprostol. Adverse events were lower in the DA-9601 group, 56.4% (95% CI, 48.0%-64.8%) than in the misoprostol group, 69.2% (95% CI, 61.3%-77.0%) (P = 0.031). DA-9601 is not inferior to misoprostol for preventing NSAID-associated gastroduodenal injury, and superior to it with respect to treatment-related side effects.

Accelerated Ulcer Healing and Resistance to Ulcer Recurrence with Gastroprotectants in Rat Model of Acetic Acid-induced Gastric Ulcer

Quality of ulcer healing (QOUH) is defined as ideal ulcer healing featuring with the fine granular ulcer scar, high functional restoration and the resistance to recurrence. This study was designed to compare the rates of QOUH achievement in rat gastric ulcer model between acid suppressant treated group and gastroprotectant treated group accompanied with elucidations of molecular mechanisms. Serosal injection of acetic acids for generating gastric ulcer and intraperitoneal (ip) injection of recombinant interleukin 1-beta (IL-1β) for recurring healed ulcer was done in SD rats. The 72 rats were divided into three groups according to treatment as follows; Group I, no further treatment, Group II, 8 weeks treatment of omeprazole, and Group III, 8 weeks of gastroprotectant treatment. IL-1β was administered for ulcer recurrence after 28 weeks of acetic acid injection. At four weeks after gastric ulcerogenesis, 58.3% (7/12) of active gastric ulcer were converted to healing stage in Group III, but 16.7% (2/12) in Group II and none in Group I, for which significant levels of epidermal growth factor, mucin, and pS2/trefoil peptide1 were contributive to these accelerated healings of Group III. ip injections of rIL-1β (200 µg/kg) at 28 weeks after acetic acid injection led to 100% of ulcer recurrence in Group I and 75.0% in Group II, but only 16.7% of Group III rats showed ulcer recurrence. Significantly attenuated levels of inflammatory cytokines including IL-2, transforming growth factor-alpha (TNF-α), cyclooxygenase-2 (COX-2), nitrotyrosine were responsible for the resistance to ulcer recurrence in Group III. Conclusively, gastroprotectant might be prerequisite in order to achieve ideal QOUH through significant inductions of remodeling.

DA-9601 suppresses 2, 4-dinitrochlorobenzene and dust mite extract-induced atopic dermatitis-like skin lesions

DA-9601 (Stillen™) is a novel anti-peptic formulation prepared from the ethanol extracts of Artemisia asiatica possessing anti-oxidative, anti-allergic and anti-inflammatory activities. However, their effect on atopic dermatitis (AD) has not been studied yet. In this study, we report that topical application of DA-9601 suppressed house dust mite extract (Dermatophagoides farinae extract, DFE) and 2, 4-dinitrochlorobenzene (DNCB)-induced AD-like skin lesions in BALB/c mice model. We established atopic dermatitis model in BALB/c mice by repeated local exposure of DFE/DNCB to the ears. Repeated alternative treatment of DFE/DNCB caused AD-like lesions. DA-9601 reduced AD-like skin lesions based on ear thickness and histopathological analysis, and serum IgE levels. DA-9601 inhibited mast cell infiltration into the ear and elevation of serum histamine in AD model. In addition, DA-9601 suppressed DFE/DNCB-induced expression of IL-4, IL-13, IL-31, and TNF-α in the ears. Taken together, our results showed that topical application of DA-9601 exerts beneficial effects in animal model of AD, suggesting that DA-9601 might be a candidate for the treatment of AD.

Eupatilin Inhibits Gastric Cancer Cell Growth by Blocking STAT3-Mediated VEGF Expression

PURPOSE

Eupatilin is an antioxidative flavone and a phytopharmaceutical derived from Artemisia asiatica. It has been reported to possess anti-tumor activity in some types of cancer including gastric cancer. Eupatilin may modulate the angiogenesis pathway which is part of anti-inflammatory effect demonstrated in gastric mucosal injury models. Here we investigated the anti-tumor effects of eupatilin on gastric cancer cells and elucidated the potential underlying mechanism whereby eupatilin suppresses angiogenesis and tumor growth.

MATERIALS AND METHODS

The impact of eupatilin on the expression of angiogenesis pathway proteins was assessed using western blots in MKN45 cells. Using a chromatin immunoprecipitation assay, we tested whether eupatilin affects the recruitment of signal transducer and activator of transcription 3 (STAT3), aryl hydrocarbon receptor nuclear translocator (ARNT) and hypoxia-inducible factor-1α (HIF-1α) to the human VEGF promoter. To investigate the effect of eupatilin on vasculogenesis, tube formation assays were conducted using human umbilical vein endothelial cells (HUVECs). The effect of eupatilin on tumor suppression in mouse xenografts was assessed.

RESULTS

Eupatilin significantly reduced VEGF, ARNT and STAT3 expression prominently under hypoxic conditions. The recruitment of STAT3, ARNT and HIF-1α to the VEGF promoter was inhibited by eupatilin treatment. HUVECs produced much foreshortened and severely broken tubes with eupatilin treatment. In addition, eupatilin effectively reduced tumor growth in a mouse xenograft model.

CONCLUSIONS

Our results indicate that eupatilin inhibits angiogenesis in gastric cancer cells by blocking STAT3 and VEGF expression, suggesting its therapeutic potential in the treatment of gastric cancer.

Effects of Morinda citrifolia aqueous fruit extract and its biomarker scopoletin on reflux esophagitis and gastric ulcer in rats

AIMS OF THE STUDY

The present study was carried out to evaluate the effect of dried mature unripe Morinda citrifolia L. (Rubiaceae) fruit, commonly known as "Noni", in an aqueous extract preparation (AFE) as used in Thai traditional medicine and its biomarker scopoletin on gastro-esophageal inflammatory models that are related to the claimed pharmacological properties of AFE and/or resembled the human esophagitis or gastric ulcer.

MATERIALS AND METHODS

The powder of dried mature unripe Noni fruit was boiled in water until it became a sticky paste and was then dried into a powder by lyophilization. The pharmacological activity of AFE and pure scopoletin at the same equivalent dose present in AFE was investigated in rat on gastro-esophageal inflammatory models (acid reflux esophagitis, acute gastritis induced by ethanol and serotonin, and chronic gastric ulcer induced by acetic acid); gastric biochemical parameters and gastrointestinal motility.

RESULTS

AFE (0.63-2.50 g/kg) significantly prevented the formation of acid reflux esophagitis, reduced the formation of ethanol-induced acute gastric lesions, suppressed the development of gastric lesions in response to serotonin, and accelerated the healing of acetic acid-induced chronic gastric ulcer in rats with equal potency to those obtained by standard antisecretory agents (ranitidine and lansoprazole). AFE also significantly inhibited gastric acid secretion and pepsin activity in pylorus ligated rats. Additionally, AFE strongly increased the gastrointestinal transit of charcoal meal with a higher potency than cisapride. Pure scopoletin, when compared at the same equivalent dose containing in AFE, possessed similar antiulcer and antisecretory properties to that of AFE although it exerted a less prokinetic activity than AFE.

CONCLUSION

The findings indicated that AFE as well as its biomarker: scopoletin may be beneficial as a potential preventive and therapeutic agent for gastro-esophageal inflammatory diseases, mainly through its antisecretory and prokinetic activities including an inhibitory activity on serotonin, free radicals, and cytokine-mediated inflammation. Additionally, scopoletin might be one of the biomarker constituents to use for the quality assessment of Noni fruit products used for treating gastro-esophageal inflammatory diseases.

Exogenous luminal nitric oxide exposure accelerates columnar transformation of rat esophagus

Exposure of the esophageal mucosa to refluxed gastroduodenal contents is recognized to be an important risk factor for Barrett's esophagus (BE). At the human gastroesophageal junction, nitric oxide is generated luminally through the enterosalivary recirculation of dietary nitrate, and in cases with gastroesophageal reflux, the site of luminal nitric oxide generation could shift to the distal esophagus. The aim of this study is to investigate whether exogenous luminal nitric oxide could promote the development of BE in rats. Sodium nitrite plus ascorbic acid were administered to a rat surgical model of BE, in which the gastroduodenal contents were refluxed into the esophagus to generate exogenous luminal nitric oxide in the esophagus by the acid-catalyzed chemical reaction between the 2 reagents. The emergence of BE was evaluated histologically in the early phase (several weeks) after the surgery with or without exogenous nitric oxide administration. To elucidate the histogenesis of BE, CDX2, MUC2 and MUC6 expressions were investigated immunohistochemically. Coadministration of sodium nitrite plus ascorbic acid significantly accelerated the timing of emergence and increased the area of BE compared with controls. Administration of either reagent alone did not show any promotive effects on BE formation. Immunohistochemically, the columnar epithelium thus induced was similar to the specialized intestinal metaplasia in human BE. The results of this animal model study suggest that exogenous luminal nitric oxide could be involved in the pathogenesis of the columnar transformation of the esophagus. Further studies in human are warranted.

Eupatilin inhibits T-cell activation by modulation of intracellular calcium flux and NF-kappaB and NF-AT activity

Eupatilin, one of the pharmacologically active ingredients of Artemisia princeps, exhibits a potent anti-ulcer activity, but its effects on T-cell immunity have not been investigated. Here, we show that eupatilin has a profound inhibitory effect on IL-2 production in Jurkat T cells as well as in human peripheral blood leukocytes. Eupatilin neither influenced clustering of CD3 and LFA-1 to the immunological synapse nor inhibited conjugate formation between T cells and B cells in the presence or absence of superantigen (SEE). Eupatilin also failed to inhibit T-cell receptor (TCR) internalization, thereby, suggesting that eupatilin does not interfere with TCR-mediated signals on the membrane proximal region. In unstimulated T cells, eupatilin significantly induced apoptotic cell death, as evidenced by an increased population of annexin V(+)/PI(+) cells and cleavage of caspase-3 and PARP. To our surprise, however, once cells were activated, eupatilin had little effect on apoptosis, and instead slightly protected cells from activation-induced cell death, suggesting that apoptosis also is not a mechanism for eupatilin-induced T-cell suppression. On the contrary, eupatilin dramatically inhibited I-kappaBalpha degradation and NF-AT dephosphorylation and, consequently, inhibited NF-kappaB and NF-AT promoter activities in PMA/A23187-stimulated T cells. Interestingly, intracellular calcium flux was significantly perturbed in cells pre-treated with eupatilin, suggesting that calcium-dependent cascades might be targets for eupatilin action. Collectively, our results provide evidence for dual regulatory functions of eupatilin: (1) a pro-apoptotic effect on resting T cells and (2) an immunosuppressive effect on activated T cells, presumably through modulation of Ca(2+) flux.

Exogenous luminal nitric oxide exacerbates esophagus tissue damage in a reflux esophagitis model of rats

OBJECTIVE

Cytotoxic concentrations of nitric oxide are generated luminally at the gastroesophageal junction through the entero-salivary recirculation of dietary nitrate in humans. The site of luminal nitric oxide generation shifts to the lower esophagus when gastric acid is refluxed into the esophagus. The aim of this study was to investigate the influence of persistent administration of exogenous nitric oxide on esophageal damage.

MATERIAL AND METHODS

0.1% sodium nitrite and/or 1% ascorbic acid was administered in an established rat acid-refluxed esophagitis model. Co-administration of both reactants in this model is thought to induce high concentrations of nitric oxide luminally in the esophagus by an acid-catalyzed chemical reaction when refluxed gastric acid is present. The tissue damage was evaluated by a macroscopic lesion index and myeloperoxidase activity. Nitrotyrosin was assessed immunohistochemically as a footprint of peroxynitrite formation.

RESULTS

Co-administration of sodium nitrite and ascorbic acid induced a 4- to 5-fold increase in the esophageal damage compared with baseline reflux esophagitis, while the damage was unchanged when either of the reagents alone was given. Nitrotyrosine was strongly stained in the tissue from the co-administration. Treatment of superoxide scavengers efficiently prevented the exacerbation of esophageal damage by exogenous nitric oxide exposure, suggesting an essential role of superoxide in esophageal damage.

CONCLUSIONS

Exogenous luminal nitric oxide greatly exacerbated the tissue damage of reflux esophagitis. Diffusion of the luminal nitric oxide into the adjacent superoxide-enriched inflamed tissue of the esophagus could lead to the production of the highly toxic agent peroxynitrite, thus causing exacerbation of the esophageal damage.

Eupatilin with heme oxygenase-1-inducing ability protects cultured feline esophageal epithelial cells from cell damage caused by indomethacin

We previously reported that eupatilin (5,7-dihydroxy-3,4,6-trimethoxyflavone) extracted from Artemisia asiaitica, augmented the cellular antioxidant defense capacity through induction of the antioxidant protein heme oxygenase-1 (HO-1), thereby protecting ileal smooth muscle cells from nonsteroidal anti-inflammatory drug (NSAID)-induced intestinal toxicity. In the present study, we used cultured feline esophageal epithelial cells (EEC) to investigate the ability of eupatilin to induce expression of HO-1 and to analyze its cytoprotective effect against indomethacin-induced damage, since NSAID users have a higher risk of esophageal ulcers or esophagitis than non-NSAID users. A culture of EEC from cat was prepared. The identity of the cultures was confirmed by immunocytochemistry using cytokeratin antibodies. Western blot analysis showed a concentration- and time- dependent expression of HO-1 in response to eupatilin. Phosphorylation of extracellular regulating protein kinase (ERKs) and Akt, and nuclear translocation of nuclear related factor 2 (Nrf2) were induced by 150 microM eupatilin in a time-dependent manner. Eupatilin-induced HO-1 expression and Nrf2 were partly attenuated by MEK inhibitor PD98059 and almost completely by phosphatidyl-inactiol 3 kinase (PI3K) inhibitor LY294002, but not by c-Jun N-terminal kinase (JNK) inhibitor SP600125 or p38 mitogen activated protein kinase (MAPK) inhibitor SB202190. MTT assay showed that treatment with 2 mM indomethacin for 2 h decreased cell viability to about 41%. Pre-treatment of cells with eupatilin resulted in the dose-dependent inhibition of indomethacin-induced cell damage. We confirmed that ZnPP, an HO-1 inhibitor, repressed eupatilin-induced HO-1 activity and showed the protective effect of eupatilin against indomethacin-induced cell injury. The data suggested that HO-1 was partly responsible for the eupatilin-mediated protective action of esophageal epithelial cells against indomethacin via both ERKs and PI3K/Akt pathways as well as Nrf2 translocation.

Melatonin protects against experimental reflux esophagitis

Reflux esophagitis (RE), a major gastrointestinal disorder results from excess exposure of the esophageal mucosa to acidic gastric juice or bile-containing duodenal contents refluxed via an incompetent lower esophageal sphincter. Recent studies implicated oxygen derived free radicals in RE induced esophageal mucosal damage resulting in mucosal inflammation. Thus, control over free radical generation and modulation of inflammatory responses might offer better therapeutic effects to counteract the severity of RE. In this context we investigated the effect of melatonin against experimental RE in rats. Melatonin pretreatment significantly reduced the haemorrhagic lesions and decreased esophageal lipid peroxidation aggravated by RE. Moreover, the depleted levels of superoxide dismutase and glutathione observed in RE were replenished by melatonin signifying its free radical scavenging properties and antioxidant effects resulting in the improvement of esophageal defense mechanism. Further melatonin repressed the upregulated levels of expression of proinflammatory cytokines like, TNF-alpha, IL-1beta and IL-6 in RE. However, increased levels of the anti-inflammatory cytokine IL-10 remained unaltered after melatonin administration signifying its immunomodulatory effect through suppression of Th1-mediated immune responses. The involvement of receptor dependent actions of melatonin against RE were also investigated with MT2 receptor antagonist, luzindole (LUZ). LUZ failed to antagonize melatonin's protective effects against RE indicating that melatonin mediated these beneficial effects in a receptor-independent fashion. Thus, esophageal mucosal protection elicited by melatonin against experimental RE is not only dependent on its free radical scavenging activity but also mediated in part through its effect on the associated inflammatory events in a receptor-independent manner.

Chemopreventive effects of the standardized extract (DA-9601) of Artemisia asiatica on azoxymethane-initiated and dextran sulfate sodium-promoted mouse colon carcinogenesis

Dextran sulfate sodium (DSS) administration has been reported to cause inflammation in mouse colonic mucosa, which promotes colon carcinogenesis. When male ICR mice were treated with a single intraperitoneal dose (10 mg/kg body weight) of azoxymethane (AOM) followed by 2.5% DSS in drinking water for 7 consecutive days, all developed tumors at the 16th wk, mostly in the distal colon. Cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) were markedly upregulated in the AOM-initiated and DSS-promoted colon tumors. The DNA binding activity of nuclear factor-kappaB (NF-kappa B) was also elevated in the colon tumors. In this study, we examined the chemopreventive effects of the standardized extract (DA-9601) of Artemisia asiatica that has been used in the traditional herbal medicine for the treatment of inflammatory disorders. Mice fed the chow diet containing 10% DA-9601 for 15 wk following DSS treatment displayed the significantly lower multiplicity of colon tumors. DA-9601 treatment suppressed the expression of COX-2 and iNOS as well as NF-kappa B DNA binding in the colonic tissues. It also downregulated the phosphorylation of extracellular, signal-regulated protein kinase and p38 mitogen-activated protein kinase that are upstream of NF-kappa B. Furthermore, DA-9601 reduced expression of beta-catenin in colonic mucosa of mice challenged with AOM plus DSS.

Eupatilin exhibits a novel anti-tumor activity through the induction of cell cycle arrest and differentiation of gastric carcinoma AGS cells

In many cases, the process of cancer cell differentiation is associated with the programmed cell death. In the present study, interestingly, we found that eupatilin, one of the pharmacologically active ingredients of Artemisia asiatica that has been reported to induce apoptosis in human gastric cancer AGS cells, also triggers differentiation of these cells. Treatment of AGS cells with eupatilin induced cell cycle arrest at the G(1) phase with the concomitant induction of p21(cip1), a cell cycle inhibitor. This led us to test whether eupatilin may trigger AGS cells to differentiate into the matured phenotypes of epithelial cells and this phenomenon may be coupled to the apoptosis. Eupatilin induced changes of AGS cells to a more flattened morphology with increased cell size, granularity, and mitochondrial mass. It also markedly induced trefoil factor 1 (TFF1), a gene responsible for the gastrointestinal cell differentiation. Eupatilin dramatically induced redistribution of tight junction proteins such as occludin and ZO-1, and F-actin at the junctional region between cells. It also induced phosphorylation of extracellular signal-regulated kinase 2 and p38 kinase. Blockade of ERK signaling by PD098059 or the dominant-negative ERK2 significantly reduced eupatilin-induced TFF1 and p21 expression as well as ZO-1 redistribution, indicating that ERK cascades may mediate eupatilin-induced AGS cell differentiation. Collectively, our results suggest that eupatilin acts as a novel anti-tumor agent by inducing differentiation of gastrointestinal cancer cells rather than its direct role in inducing apoptotic cell death.

Sodium deoxycholate causes nitric oxide mediated DNA damage in oesophageal cells

Patients with chronic gastro-oesophageal reflux disease experience the reflux of acid and bile into the distal oesophagus. The secondary bile salt sodium deoxycholate (NDC) is implicated in the induction of mucosal injury during reflux episodes. This study hypothesized that NDC damages DNA in oesophageal cells by an oxidative mechanism. In the oesophageal cell line HET1-A, increased production of nitric oxide (NO) was measured in NDC-treated cells. Protection from DNA strand breaks induced by NDC (10 microm) was observed in cells coincubated with the nitric oxide scavenger C-PTIO (p<0.012) or pre-incubated with the NO synthase inhibitor L-NAME (p<0.009) or the NFkappaB inhibitor, TPCK (p<0.036). Collectively these data implicate the involvement of NFkappaB and nitric oxide synthase in the DNA damage induced by NDC in oesophageal cells. In conclusion, NDC-driven NO production may play an important role in inducing DNA damage during episodes of gastro-oesophageal reflux and thereby contribute to reflux-related carcinogenesis.

The protective effect of eupatilin on indomethacin-induced cell damage in cultured feline ileal smooth muscle cells: involvement of HO-1 and ERK

Chronic users of non-steroidal anti-inflammatory drugs frequently develop ulcerative lesions in their intestines. The purpose of the present study was to investigate whether eupatilin, an active ingredient derived from Artemisia plants, prevents this side effect in vitro. Extracts of the whole herb of Artemisia asiatica Nakai have been used in oriental medicine for the treatment of inflammation. As measured by the MTT assay, the treatment of cultured feline ileal smooth muscle cells (ISMCs) with 2.5mM indomethacin for 2h decreased the cell viability to 43%. Pretreatment with eupatilin resulted in dose-dependent inhibition on indomethacin-induced cell damage. This cytoprotective effect of eupatilin required concentrations of more than 150 microM and incubation periods of longer than 16 h. Pretreatment of ISMC with cycloheximide, an inhibitor of protein synthesis, attenuated the cytoprotective effect of eupatilin, suggesting that eupatilin induces proteins that are responsible for the cytoprotection. Heme oxygenase-1 (HO-1), which is known as a cytoprotective enzyme due to its anti-inflammatory actions, is a candidate protein since ZnPP, an HO-1 inhibitor, repressed the protective effect of eupatilin on indomethacin-induced cell damage in a concentration-dependent manner. Western blot analysis revealed that eupatilin-mediated HO-1 induction occurred in a concentration- and time-dependent manner. We also found that PD98059, a MEK (MAPK/ERK kinase) inhibitor, attenuated the eupatilin-induced HO-1 expression and nuclear translocation of transcription factor Nrf2 (nuclear factor erythroid 2-related factor 2). Taken together, the data imply that eupatilin protects ISMC from cell damage caused by indomethacin, and that its cytoprotective action could be attributed to eupatilin-mediated HO-1 induction via ERK and Nrf2 signaling in ISMC.

Eupatilin inhibits H(2)O(2)-induced apoptotic cell death through inhibition of mitogen-activated protein kinases and nuclear factor-kappaB

Eupatilin (5,7-dihydroxy-3',4',6-trimethoxyflavone), an extract from Artemisia asiatica Nakai, is a flavonoid of pharmacologically active ingredients. Eupatilin is known to possess anti-cancer, anti-inflammatory, and anti-oxidative activity. Recently, eupatilin has been reported to be effective in producing gastric mucosal as an anti-gastritis agents. However, the mechanism of protective action is still unknown. We studied cytoprotective actions of eupatilin on H(2)O(2)-induced cell death and its possible mechanisms of action in human gastric (AGS) cells. Eupatilin dose-dependently inhibited H(2)O(2)-induced apoptosis as indicated by co-staining with Annexin V and propidium iodide. Hydrogen peroxide provoked phosphorylation of extracellular regulated kinase (ERK) and c-Jun NH(2)-terminal kinase (JNK), and activation of nuclear factor-kappaB (NF-kappaB). On the contrary, eupatilin decreased H(2)O(2)-induced activation of ERK, JNK and NF-kappaB. In addition, treatment of specific inhibitors for ERK, JNK, and NF-kappaB attenuated H(2)O(2)-induced apoptosis. Co-treatment of inhibitors and eupatilin was more effective in decreasing H(2)O(2)-induced apoptosis. Taken together, we suggest that eupatilin inhibits H(2)O(2)-induced apoptosis through the inhibition ERK, JNK, and NF-kappaB.

Efficacy of the natural antioxidant astaxanthin in the treatment of functional dyspepsia in patients with or without Helicobacter pylori infection: A prospective, randomized, double blind, and placebo-controlled study

OBJECTIVES

The aim of this study was to evaluate the efficacy of the natural antioxidant astaxanthin in functional dyspepsia in different doses and compared with placebo.

DESIGN

The study was a controlled, prospective, randomized, and double blind trial.

PARTICIPANTS

Patients with functional dyspepsia, divided into three groups with 44 individuals in each group (placebo, 16mg, or 40mg astaxanthin, respectively).

INTERVENTIONS

Participants were asked to accept gastroscopy before treatment, together with questionnaires: GSRS and SF-36. Urea breath test (UBT) was done before the treatment.

MAIN OUTCOME

The primary objective was to test the hypothesis that the antioxidant astaxanthin at two doses regimens compared to placebo should ameliorate gastrointestinal discomfort measured as GSRS in patients with functional dyspepsia, who were either positive or negative for Helicobacter pylori, after 4 weeks of treatment.

RESULTS

At the end of therapy (week 4) no difference between the three treatment groups was observed regarding mean Gastrointestinal Symptom Rating Scale (GSRS) scores of abdominal pain, indigestion and reflux syndromes. The same results were observed at the end of follow-up. However reduction of reflux syndrome before treatment to week 4 was significantly pronounced in the higher (40mg) dose compared to the other treatment groups (16mg and placebo, p=0.04).

CONCLUSION

In general, no curative effect of astaxanthin was found in functional dyspepsia patients. Significantly greater reduction of reflux symptoms were detected in patients treated with the highest dose of the natural antioxidant astaxanthin. The response was more pronounced in H. pylori-infected patients.

Leukocyte telomere length predicts cancer risk in Barrett's esophagus

PURPOSE

Leukocyte telomere length has gained attention as a marker of oxidative damage and age-related diseases, including cancer. We hypothesize that leukocyte telomere length might be able to predict future risk of cancer and examined this in a cohort of patients with Barrett's esophagus, who are at increased risk of esophageal adenocarcinoma and thus were enrolled in a long-term cancer surveillance program.

PATIENTS AND METHODS

In this prospective study, telomere length was measured by quantitative PCR in baseline blood samples in a cohort of 300 patients with Barrett's esophagus followed for a mean of 5.8 years. Leukocyte telomere length hazard ratios (HR) for risk of esophageal adenocarcinoma were calculated using multivariate Cox models.

RESULTS

Shorter telomeres were associated with increased esophageal adenocarcinoma risk (age-adjusted HR between top and bottom quartiles of telomere length, 3.45; 95% confidence interval, 1.35-8.78; P = 0.009). This association was still significant when individually or simultaneously adjusted for age, gender, nonsteroidal anti-inflammatory drug (NSAID) use, cigarette smoking, and waist-to-hip ratio (HR, 4.18; 95% confidence interval, 1.60-10.94; P = 0.004). The relationship between telomere length and cancer risk was particularly strong among NSAID nonusers, ever smokers, and patients with low waist-to-hip ratio.

CONCLUSION

Leukocyte telomere length predicts risk of esophageal adenocarcinoma in patients with Barrett's esophagus independently of smoking, obesity, and NSAID use. These results show the ability of leukocyte telomere length to predict the risk of future cancer and suggest that it might also have predictive value in other cancers arising in a setting of chronic inflammation.

Neither Antioxidants nor COX-2 Inhibition Protect Against Esophageal Inflammation in an Experimental Model of Severe Reflux

BACKGROUND

Reflux-induced injury and oxidative stress result in esophageal inflammation and the potential for progression to intestinal metaplasia and adenocarcinoma. Proton-pump inhibitors represent the standard medical approach, but anti-inflammatories and antioxidants offer novel therapeutic possibilities.

MATERIALS AND METHODS

Six weeks after an esophagojejunostomy reflux procedure, female Wistar rats (n = 100) were randomized to receive either an antioxidant (vitamin C, 8 mg or 28 mg/day), a cyclooxygenase-2 (COX-2) inhibitor (rofecoxib, 1 mg/day), or no therapy. After sacrifice 16 weeks later, esophageal injury was scored using pathologic and image analysis scoring.

RESULTS

Esophagitis was present in all 63 animals completing the study and was severe in 27 (43%). No animal developed metaplasia or tumor. The extent of inflammation and esophageal ulceration were not significantly different between experimental groups.

CONCLUSIONS

In this model of reflux injury, antioxidants and COX-2 inhibitors failed to ameliorate the severe inflammation induced. Further experimental designs should evaluate these novel approaches in less severe experimental models.

The expression of 8-hydroxydeoxyguanosine in oesophageal tissues and tumours

PURPOSE

The most common marker of oxidative DNA damage is 8-hydroxydeoxyguanosine (8-OHdG), which is linked with several malignancies. In the present study we investigated whether DNA damage linked to oxidative stress (as 8-OHdG) is present in Barrett's mucosa with or without associated adenocarcinoma or high-grade dysplasia and in normal controls' squamous mucosa.

EXPERIMENTAL DESIGN

We measured 8-OHdG in 51 patients (13 Barrett's metaplasia, six Barrett's oesophagus with high-grade dysplasia, 18 adenocarcinoma of the distal oesophagus/oesophagogastric junction and 14 normal controls). The amount of DNA damage was determined by high-performance liquid chromatography in oesophagus samples obtained either from endoscopy or as samples from surgery. The median 8-OHdG concentration was expressed as the ratio of 8-OHdG per 10(5) deoxyguanosine.

RESULTS

Analysis revealed that 8-OHdG was present in both Barrett's metaplasia with and without dysplasia as well as in adenocarcinoma of the oesophagus/oesophagogastric junction. Although the study group was small the amount of 8-OHdG was significantly increased in the distal oesophagus both in Barrett's epithelium 1.26 (0.08-29.47) and in high-grade dysplasia 1.35 (1.04-1.65) as well as in adenocarcinoma of oesophagus/oesophagogastric junction 1.08 (0.59-1.94) compared to controls 0.06 (0-4.08) (p=0.002, p=0.012, p=0.001, respectively). Barrett's patients had no significant difference in 8-OHdG levels between their distal and proximal oesophageal samples.

CONCLUSIONS

Our results show the presence of oxidative DNA damage in the distal oesophagus of patients with Barrett's oesophagus and adenocarcinoma of the oesophagus/oesophagogastric junction. This may have a connection to carcinogenesis in Barrett's oesophagus.

Protective effects of Helicobacter pylori against gastroesophageal reflux disease may be due to a neuroimmunological anti-inflammatory mechanism

There is some evidence that Helicobacter pylori infection has a protective effect against gastroesophageal reflux disease (GORD) and its complications such as Barrett's oesophagus and oesophageal adenocarcinoma. In this paper, we propose that a neuroimmunological mechanism is responsible for the protective effect of H. pylori on GORD. H. pylori infection of the gastric mucosa induces a T helper1-like immune response and production of pro-inflammatory cytokines. These cytokines can inhibit local sympathetic tone, whereas they increase systemic sympathetic tone. Increased sympathetic tone can induce an anti-inflammatory milieu, which in turn can inhibit inflammation in the oesophagus and lower oesophageal sphincter (LOS). Furthermore, H. pylori infection may stimulate the cholinergic anti-inflammatory pathway. It has been suggested that reflux-induced oesophageal inflammation plays an important role in the pathogenesis of reflux oesophagitis. Reduction of oesophageal inflammation by increased systemic sympathetic tone and vagal activity may lead to a decrease in reflux-induced oesophageal injury and LOS dysfunction in GORD.

Neither Antioxidants nor COX-2 Inhibition Protect Against Esophageal Inflammation in an Experimental Model of Severe Reflux

BACKGROUND

Reflux-induced injury and oxidative stress result in esophageal inflammation and the potential for progression to intestinal metaplasia and adenocarcinoma. Proton-pump inhibitors represent the standard medical approach, but anti-inflammatories and antioxidants offer novel therapeutic possibilities.

MATERIALS AND METHODS

Six weeks after an esophagojejunostomy reflux procedure, female Wistar rats (n = 100) were randomized to receive either an antioxidant (vitamin C, 8 mg or 28 mg/day), a cyclooxygenase-2 (COX-2) inhibitor (rofecoxib, 1 mg/day), or no therapy. After sacrifice 16 weeks later, esophageal injury was scored using pathologic and image analysis scoring.

RESULTS

Esophagitis was present in all 63 animals completing the study and severe in 27 (43%). No animal developed metaplasia or tumor. The extent of inflammation and esophageal ulceration were not significantly different between experimental groups.

CONCLUSIONS

In this model of reflux injury, antioxidants and COX-2 inhibitors failed to ameliorate the severe inflammation induced. Further experimental designs should evaluate these novel approaches in less severe experimental models.

Immune and Inflammatory Responses in GERD and Lansoprazole

The exact pathophysiological mechanisms responsible for gastroesophageal reflux disease (GERD) remain unclear. Recent studies have shown that mucosal immune and inflammatory responses, characterized by specific cytokine and chemokine profiles, may underlie the diverse esophageal phenotypes of GERD. Interleukin 8 (IL-8), a representative chemokine, mediates neutrophil trafficking via its receptors, mainly CXCR-1. The IL-8 mRNA and protein levels are increased in the esophageal mucosa, not only in reflux esophagitis (RE), but also in endoscopy-negative GERD (NERD), through activation of nuclear factor-kappaB (NF-kappaB), which is a pivotal transcription factor. Mucosal IL-8 concentrations have been found to parallel the endoscopic severity of RE, implying that this cytokine is a key player in the development of GERD. The mucosal levels of the C-C chemokines, macrophage chemoattractant protein 1 (MCP-1) and regulated on activation normal T-cell-expressed and presumably secreted (RANTES), which primarily attract monocytes and lymphocytes to the site of inflammation, respectively, are also elevated in RE. The secreted levels of IL-8 and IL-1beta, a prototype of proinflammatory cytokine, are maximal at the proximal segment within Barrett esophagus (BE) tissue. The expression of the two pleiotrophic proinflammatory cytokines, IL-6 and tumor necrosis factor alpha, is enhanced in the intestinal epithelium of BE, which places this epithelium at a higher risk for developing malignancy. BE is characterized by a distinct Th-2 predominant cytokine profile (IL-4 and -10), compared to the proinflammatory nature of RE (interferone-gamma). Treatment with a proton pump inhibitor, lansoprazole reduces the mucosal levels of IL-8 mRNA and protein in GERD, including RE and NERD. This may occur in part through an anti-inflammatory action of proton pump inhibitors beyond gastric acid inhibition.

Chromosomal instability in Barrett's esophagus is related to telomere shortening

Barrett's esophagus is a useful model for the study of carcinogenesis, as the metaplastic columnar epithelium that replaces squamous esophageal epithelium is at elevated risk for development of adenocarcinoma. We examined telomere length and chromosomal instability (CIN) in Barrett's esophagus biopsies using fluorescence in situ hybridization. To study CIN, we selected centromere and locus-specific arm probes to chromosomes 17/17p (p53), 11/11q (cyclin D1), and 9/9p (p16 INK4A), loci reported to be involved in early stages of Barrett's esophagus neoplasia. Telomere shortening was observed in Barrett's esophagus epithelium at all histologic grades, whereas CIN was highest in biopsies with dysplastic changes; there was, however, considerable heterogeneity between patients in each variable. Alterations on chromosome 17 were strongly correlated with telomere length (r = 0.55; P < 0.0001) and loss of the 17p arm signal was the most common event. CIN on chromosome 11 was also associated with telomere shortening (r =0.3; P = 0.05), although 11q arm gains were most common. On chromosome 9p, arm losses were the most common finding, but chromosome 9 CIN was not strongly correlated with telomere length. We conclude that CIN is related to telomere shortening in Barrett's esophagus but varies by chromosome. Whether instability is manifested as loss or gain seems to be influenced by the chromosomal loci involved. Because telomere shortening and CIN are early events in Barrett's esophagus neoplastic progression and are highly variable among patients, it will be important to determine whether they identify a subset of patients that is at risk for more rapid neoplastic evolution.

DA-9601 inhibits activation of the human mast cell line HMC-1 through inhibition of NF-kappaB

Mast cell-mediated allergic inflammation is involved in many diseases such as asthma, sinusitis, and rheumatoid arthritis. Mast cells induce synthesis and production of pro-inflammatory cytokines including tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta and IL-6 with immune regulatory properties. The formulated ethanol extract of Artemisia asiatica Nakai (DA-9601) has been reported to have antioxidative and anti-inflammatory activities. In this report, we investigated the effect of DA-9601 on the expression of pro-inflammatory cytokines by the activated human mast cell line HMC-1 and studied its possible mechanisms of action. DA-9601 dose-dependently decreased the gene expression and production of TNF-alpha, IL-1beta, and IL-6 on phorbol 12-myristate 13-acetate (PMA)- and calcium ionophore A23187-stimulated HMC-1 cells. In addition, DA-9601 attenuated PMA- and A23187-induced activation of NF-kappaB as indicated by inhibition of degradation of IkappaBalpha, nuclear translocation of NF-kappaB, NF-kappaB/DNA binding, and NF-kappaB-dependent gene reporter assay. Our in vitro studies provide evidence that DA-9601 might contribute to the treatment of mast cell-derived allergic inflammatory diseases.

Review article: the role of bile and pepsin in the pathophysiology and treatment of gastro-oesophageal reflux disease

Gastro-oesophageal reflux disease is a multifaceted and multifactorial disorder which results from the reflux of gastric contents into the oesophagus. Animal studies suggest that synergism between acid and pepsin and conjugated bile acids have the greatest damaging potential for oesophageal mucosa, although unconjugated bile acids may be caustic at more neutral pH. Human studies are compatible with a synergistic action between acid and duodenogastric reflux in inducing lesions. During prolonged monitoring studies, typical gastro-oesophageal reflux symptoms are more related to acid reflux events than to non-acid reflux events. However, symptoms that persist during acid suppressive therapy are often related to non-acid reflux events. The therapeutic options for the non-acid component of the refluxate, including acid suppression, prokinetics, baclofen, surgery and mucosal protective agents like alginates, are discussed.

DA-9601, a standardized extract of Artemisia asiatica, blocks TNF-α-induced IL-8 and CCL20 production by inhibiting p38 kinase and NF-κB pathways in human gastric epithelial cells

AIM: To investigate whether, or how, DA-9601, which is a new gastroprotective agent, inhibits TNF-α-induced inflammatory signals in gastric epithelial AGS cells.

METHODS: Cell viability was determined by MTT assay. IL-8 and CCL20 promoter activities were determined by a luciferease reporter gene assay. NF-κB-dependent transcriptional activity was determined by I-κBα degradation, NF-κB p65 nuclear translocation and a luciferase activity assay. IL-8 and CCL20 gene expression and protein secretion were determined by RT-PCR and an enzyme-linked immunosorbent assay (ELISA). Total and phosphorylated forms of mitogen-activated protein kinases (MAPKs) were determined by Western blot.

RESULTS: Treatment of AGS cells with DA-9601 reduced TNF-α-induced IL-8 and CCL20 promoter activities, as well as their gene expression and protein release. TNF-α also induced NF-κB-dependent transcriptional activity in AGS cells. In contrast, in cells treated with DA-9601, TNF-α-induced NF-κB activity was significantly blocked. Although all three MAP kinase family members were phosphorylated in response to TNF-α, a selective inhibitor of p38 kinase SB203580 only could inhibit both NF-κB-dependent transcriptional activity and IL-8 and CCL20 production, suggesting a potential link between p38 kinase and NF-κB-dependent pathways in AGS cells. Interestingly, DA-9601 also selectively inhibited p38 kinase phosphorylation induced by TNF-α.

CONCLUSION: DA-9601 blocked TNF-α-mediated inflammatory signals by potentially modulating the p38 kinase pathway and/or a signal leading to NF-κB-dependent pathways in gastric epithelial cells.

Eupatilin attenuates bile acid-induced hepatocyte apoptosis

BACKGROUND

In cases of cholestasis, bile acids induce hepatocyte apoptosis by activating death receptor-mediated apoptotic signaling cascades. Eupatilin (5,7-dihydroxy-3,4,6-trimethoxyflavone) is a pharmacologically active ingredient found in Artemisia asiatica and exhibits cytoprotective effects against experimentally induced gastrointestinal, pancreatic, and hepatic damage. This study was undertaken to examine if eupatilin modulates bile acid-induced hepatocyte apoptosis.

METHODS

Huh-BAT cells, a human hepatocellular carcinoma cell line stably transfected with a bile acid transporter, were used in this study. Apoptosis was quantified using 4',6-diamidino-2-phenylindole dihydrochloride staining, and its signaling cascades were explored by immunoblot analysis. Kinase signaling was evaluated by immunoblotting and by using selective inhibitors. Eupatilin's in vivo effect on bile acid-induced hepatocyte apoptosis was explored in bile duct-ligated rats.

RESULTS

Eupatilin significantly reduced bile acid-mediated hepatocyte apoptosis by attenuating bile acid-induced caspase 8 cleavage. Eupatilin diminished the bile acid-induced activation of mitogen-activated protein kinases, including p38 mitogen-activated protein kinase and c-Jun N-terminal kinase. In particular, the eupatilin-mediated inhibition of bile acid-induced c-Jun N-terminal kinase activation was found to be responsible for attenuating caspase 8 cleavage. Moreover, eupatilin diminished hepatocyte apoptosis in bile duct-ligated rats.

CONCLUSIONS

Eupatilin attenuates bile acid-induced hepatocyte apoptosis by suppressing bile acid-induced kinase activation. Therefore, eupatilin might be therapeutically efficacious in a variety of human liver diseases associated with cholestasis.

Effects of curcumin on reflux esophagitis in rats

The preventive effect of curcumin, a compound isolated from the rhizome of Curcuma longa, on experimental reflux esophagitis in rats was investigated in order to validate its potential therapeutic use for gastroesophageal reflux disease. Curcumin (20 mg/kg, i.d.), the antioxidative agent dimethyl sulfoxide (DMSO) (1 ml/kg, i.p.) or the proton pump inhibitor lansoprazole (1 mg/kg, i.d.) inhibited the formation of acute acid reflux esophagitis by 52.5, 61.5 and 70.9% respectively. Curcumin alone was not effective in preventing chronic acid reflux esophagitis, but the combination of curcumin and DMSO reduced the mortality rate and the severity of the esophagitis ulcer index to the same extent (56.5%) as did the lansoprazole (53.9%). Intraduodenal administration of curcumin also markedly prevented the formation of acute mixed reflux esophagitis, together with reducing the incidence or the severity of neutrophil infiltration, when compared to a control group. In contrast, lansoprazole tended to increase the severity of all histopathological changes, when compared to either the control or the curcumin-treated group. Aminoguanidine, a specific inducible nitric oxide synthase inhibitor, had no preventive effect against both types of acute reflux esophagitis models, and increased the mortality in the chronic acid reflux esophagitis model. From these results, it is indicated that curcumin can effectively prevent acute reflux esophagitis formation. Although curcumin is less potent than lansoprazole in inhibiting acid reflux esophagitis, it is superior to lansoprazole in inhibiting mixed reflux esophagitis. The antiulcerogenic mechanisms are considered to be closely associated with its antioxidant nature and antiinflammatory property.

Helicobacter pylori extract induces nuclear factor-kappa B, activator protein-1, and cyclooxygenase-2 in esophageal epithelial cells

Helicobacter pylori infection is recognized as the major cause of gastritis and gastric cancer; however, its role in the development of gastroesophageal reflux disease and Barrett's adenocarcinoma is unclear. The expression of NF-kappaB, AP-1, and COX-2 may be important in inflammation and tumorigenesis in the esophagus. The aim of this study was to examine the effect of live H pylori or H pylori extract (HPE) on these factors in the esophageal epithelial cell lines SKGT-4 and OE33. NF-kappaB and AP-1 activity were assessed by gel shift assay and COX-2 by Western blotting. Coculture of SKGT-4 and OE33 with live H pylori and HPE induced NF-kappaB and AP-1 DNA-binding activity, and also decreased IkappaB-alpha levels. Treatment with the specific MEK1/2 MAPK inhibitor PD98059, but not the p38 MAPK inhibitor SB203580, inhibited NF-kappaB and AP-1 activity. The antioxidant vitamin C inhibited H pylori-induced NF-kappaB activation, but increased AP-1 expression. Moreover, HPE induced COX-2 expression and IL-8 production, and PD98059 inhibited COX-2 expression, ERK1/2 phosphorylation, and IL-8 production. These data demonstrate that both live H pylori and HPE induce NF-kappaB and AP-1 expression in esophageal epithelial cells. The induction of such transcription factors may play a role in the specific immune response within Barrett's mucosa and may indirectly cause inflammation of the gastric cardia and the distal esophagus.

Pharmacological targets in gastro-oesophageal reflux disease

Although proton pump inhibitors have become the mainstay of treatment in gastro-oesophageal reflux disease (GORD), there are still unmet needs in the management of this very common disorder. For example, all current proton pump inhibitors have a relatively slow onset of action and their activity is limited mainly to the post-prandial period with far less effective inhibition of nocturnal acid secretion. In order to achieve more potent, rapid and sustained acid inhibition several compounds are currently under development, such as new proton pump inhibitors with a prolonged plasma half-life, potassium competitive ATPase blockers (PCABs), histamine H3 agonists, and gastrin antagonists. Acid suppression does not, however, cure the disease and relapses are frequently observed after discontinuation of proton pump inhibitor therapy. Among the different abnormalities involved in the pathophysiology of this multifactorial disease, transient lower oesophageal sphincter relaxations represent the major mechanism responsible for episodes of reflux. Baclofen, the prototype GABA(B) receptor agonist, is one of the most potent inhibitors of transient lower oesophageal sphincter relaxations identified. To date the transfer of these relaxation-controlling pharmacological agents into clinical practice has however been hampered by the occurrence of unacceptable side effects. Beside "anti-relaxation therapy", the potential of novel prokinetics such as motilin agonists has been explored, especially since the motilin receptor has been cloned. Thus far the broad therapeutic value of prokinetics in GORD does, however, seem very limited in terms of efficacy with respect to oesophageal motility and acid exposure. Lastly, further research is necessary to better understand the complex mechanisms involved in oesophageal sensitivity and mucosal defence.

A novel external esophageal perfusion model for reflux esophageal injury

The current animal models of esophagitis and Barrett's esophagus consist of surgeries that divert the gastroduodenal contents to the esophagus. The limitations of these models are the inability to control the amount and concentration of the refluxate and the causing of significant postoperative stress and morbidity. Eighteen adult rats were cannulated at the upper esophagus and connected to a subcutaneous osmotic micropump to perfuse the esophageal lumen with bile and acid. Animals were sacrificed after 7 days of perfusion. Histological changes were determined. Cell proliferation, apoptosis, lipid peroxidation, and glutathione were measured. Histopathological changes in the bile- or acid-perfused esophagus were consistent with the findings associated with reflux esophagitis. Enhanced proliferation and apoptosis were seen, along with increased oxidative stress. The external esophageal perfusion model enabled precise control of the injurious agent. It induced the histologic and cellular injury of reflux esophagitis after 7 days.

Role of pancreatic trypsin in chronic esophagitis induced by gastroduodenal reflux in rats

BACKGROUND

Reflux of the duodenal contents with gastric acid has been reported to contribute to the development of esophageal mucosal damage and inflammation. Recent studies show that pancreatic trypsin can stimulate the production of inflammatory mediators, including chemokines and prostaglandins from human esophageal epithelial cells in vitro. The aim of the present study was to investigate the role of pancreatic trypsin in the pathogenesis of chronic esophageal inflammation induced by gastroduodenal reflux in rats.

METHODS

Esophagogastroduodenal anastomosis was carried out in male Wistar rats by anastomosing the jejunum to the gastroesophageal junction under diethyl ether inhalation anesthesia. The animals undergoing surgery were treated with the control diet, rabeprazole sodium, nizatidine, ecabet sodium, camostat mesilate (CMM), ONO-1714, a specific inducible nitric oxide synthase (iNOS) inhibitor, or meloxicam, a selective cyclooxygenase-2 (COX-2) inhibitor. Esophageal injury was evaluated by macroscopic and microscopic findings, and mRNA expression for CINC-1, COX-2, and iNOS was determined by real-time polymerase chain reaction (PCR). Trypsin activity within the esophageal lumen was measured 2 weeks after surgery, and the expression of protease-activated receptor (PAR)-1 and -2 was confirmed by reverse transcription (RT)-PCR.

RESULTS

At 8 weeks after surgery, gastroduodenal reflux induced esophageal erosions and ulcer formation as well as marked thickening of the esophageal wall. Histological study showed an increase of thickness of the esophageal mucosa, hyperplasia of the epidermis and basal cells, ulcer formation, and marked infiltration of inflammatory cells. The macroscopic ulcer score and histological ulcer length were significantly reduced by treatment with rabeprazole or CMM but not by nizatidine or ecabet sodium, compared with each control. Rabeprazole, nizatidine, or ecabet sodium did not affect the severity of mucosal hyperplastic scores or histological parameters in esophagitis. In contrast, the CMM group showed a significant decrease in the mucosal hyperplastic and inflammatory scores. The enhanced expression of CINC-1, COX-2, and iNOS mRNA in the control group was also markedly inhibited in the CMM-treated group. ONO-1714 or meloxicam treatment significantly reduced the macroscopic scores of ulcer and hyperplasia. The trypsin activity in the esophageal lumen was significantly increased in the control diet group, and this increase was significantly inhibited in the CMM-treated group. The expression of PAR-1 and -2 mRNA was confirmed in rat esophageal epithelium.

CONCLUSIONS

With this model, we have demonstrated that CMM significantly reduces inflammation and hyperplasia in the esophageal mucosa. These results indicate that trypsin, which is primarily inhibited by CMM, plays an important role in the mucosal damage induced by gastroduodenal reflux and that it can be a therapeutic target in patients with gastroduodenal reflux esophagitis.

Oxidative damage in an experimentally induced gastric and gastroduodenal reflux model

The exact pathophysiologic mechanisms of esophageal cell damage and carcinogenesis by gastroesophageal reflux are not clearly understood. The aim of this study was to evaluate the damage to the esophageal epithelium that occurs after acid reflex and mixed acid and bile reflux by assessing histopathology, reactive oxygen species, and DNA damage. Eighty 10-week-old male Sprague-Dawley rats were divided into two groups, an acid reflux group and a mixed (acid/bile) reflux group. Acid reflux was achieved by esophagogastroplasty in which mixed reflux was encouraged via esophagoduodenal anastomosis. Each group contained a control subgroup that underwent sham laparotomy alone. The rats were killed 3, 6, 9, and 12 months after surgery. Malondialdehyde, protein carbonyl content, and DNA damage were determined in lymphocytes. Histopathologic analysis was performed according to the histologic activity index. Inflammation, ulcer, and regeneration in both reflux groups were significantly increased in the esophagus at 3, 6, 9, and 12 months compared with the control group. Mucosal damage was greater in the mixed reflux group compared with the gastric reflux group. Malondialdehyde and carbonyl content in the serum, and DNA damage in lymphocytes, were significantly increased in both reflux groups. At 9 and 12 months, oxidative damage was increased in the mixed reflux group compared with the acid reflux group. Oxygen-derived free radicals seem to be one of the important mediators in the evaluation and generation of reflux esophagitis. The impact of oxygen free radicals, as demonstrated in this study, can be evaluated by assessing the damage that they incur to lipid membranes, serum proteins, and circulating lymphocyte DNA. Serum malondialdehyde and carbonyl content as well as lymphocyte DNA damage were significantly increased in the setting of acid and mixed acid/bile reflux in these rodent models. Further, these serum and lymphocytic changes were associated with esophageal ulceration, inflammation, and regeneration. Evaluation of such markers as serum malondialdehyde and carbonyl content as well as evaluation of lymphocyte DNA might prove to be useful investigations in patients with precancerous and cancerous conditions in addition to conventional methods of diagnosis. Further studies, both animal and human are warranted.

Therapeutic effect of DA-9601 on chronic reflux gastritis induced by sodium taurocholate in rats

AIM

To investigate the therapeutic effects of DA-9601 on sodium taurocholate (TCA)-induced chronic reflux gastritis in SD rats.

METHODS

In this study, we have investigated the therapeutic effects of DA-9601 on chronic erosive and atrophic gastritis induced by 6 mo of TCA administration (5 mmol/L in drinking water) in SD rats.

RESULTS

Four weeks of DA-9601 administration (0.065%, 0.216% in rat chow), following the withdrawal of TCA treatment, resulted in a significant decrease in total length of erosions in rats in a dose-dependent manner. Furthermore, the indicators of atrophic gastritis, such as reduced mucosal thickness and reduction in the number of parietal cells, were improved by the administration of DA-9601 in a dose-related manner. DA-9601 also attenuated inflammatory cell infiltration and the proliferation of collagenous fiber in the gastric mucosa. The improvement in the reduction of the gastric mucus was observed in the rats receiving a high dose of DA-9601 (0.216%). The therapeutic effect of DA-9601 on experimental chronic erosive gastritis was superior to that of rebamipide (1.08% in rat chow). Biochemical analyses showed increased mucosal prostaglandin E2 and reduced glutathione levels by DA-9601 treatment.

CONCLUSION

We suggest that DA-9601 is a promising agent for the treatment of chronic erosive and atrophic gastritis with an etiological factor of bile reflux. Increased mucosal prostaglandin E2 and reduced glutathione by DA-9601 treatment may be therapeutic mechanisms for chronic erosive and atrophic gastritis.

The impact of antireflux surgery on oxidative stress of esophageal mucosa caused by gastroesophageal reflux disease: 4-yr follow-up study

BACKGROUND AND AIM

Oxidative stress to esophageal mucosa plays a key role in the pathogenesis of gastroesophageal reflux disease (GERD), Barrett's esophagus, and adenocarcinoma. We investigated whether successful antireflux surgery eliminates oxidative stress.

METHODS

Oxidative stress of esophageal mucosa was measured in 20 GERD patients, before antireflux surgery and 6 and 48 months after it, and compared with normal controls' mucosa (N = 9). Preoperatively, 12 of the 20 had erosive esophagitis or Barrett's metaplasia. Postoperatively, healing of GERD was verified with endoscopy and 24-h pH monitoring. We measured oxidative stress by myeloperoxidase activity (MPA), superoxide dismutase activity, and glutathione content (GSH) in distal esophagus samples from endoscopy.

RESULTS

No patient had reflux symptoms after surgery, and pH measurements had normalized. MPA in the distal esophagus decreased (p < 0.05) after successful antireflux surgery, but remained higher than that of controls both 6 months and 4 yr postoperatively (p < 0.05). At all time-points, MPA was higher in patients with preoperatively detected erosive reflux disease (ERD) as compared to non-erosive reflux disease (NERD) (p < 0.01, p < 0.05, and p < 0.05, respectively). GSH values decreased with time only in NERD. At all time-points, GSH levels in distal esophagus were lower than control levels.

CONCLUSIONS

Antireflux surgery can heal macroscopic esophagitis but cannot fully reverse the oxidative stress (as reflected by MPA and GSH) upon the distal esophageal mucosa.

Esophageal injury with external esophageal perfusion

BACKGROUND

External esophageal perfusion (EEP) with the idea that esophageal perfusion can be controlled with a single ingredient at a constant rate and concentration, might be used to dissect the injurious role of gastro-duodenal secretions for the progression from esophagitis to Barrett's esophagus (BE) and esophageal adenocarcinoma (EAC). This study is to evaluate the EEP rat model for esophagitis induced by using a micro-osmotic pump with bile perfusion.

METHODS

Eighteen adult rats underwent the EEP procedure. Bile (0.5% bovine bile, pH 7.4) was used as perfusion agent and three types of perfusions were performed: 1 week perfusion, 2 weeks perfusion, and 4 weeks perfusion compared to saline perfusion and sham operation. Histological changes, cell proliferation, apoptosis, 8-hydroxy-deoxyguanosine (8-OH-dG) and Manganese superoxide dismutase (MnSOD) were observed after perfusion and compared.

RESULTS

The bile perfusion for 1 week, 2 weeks, and 4 weeks induced mucosa infiltration of inflammatory cells, basal cell hyperproliferation, and papillae hypertrophy in all animals. Histopathology and cellular changes consistent with the findings associated with reflux esophagitis. The apoptotic index, the proliferating index, and expression of 8-OH-dG were significantly increased in the esophageal mucosa compared to controls. MnSOD expression was decreased with bile perfusion compared to saline controls.

CONCLUSIONS

The external esophageal perfusion model enabled precise control of the injurious agent. It induced the typical histological injury and cellular changes seen in severe reflux esophagitis. The cellular changes in apoptosis, proliferation and anti-oxidant defense make this model unique for reflux esophagitis studies. Further studies are needed to induce Barrett's esophagus and esophageal adenocarcinoma.

Prevention by rebamipide of acute reflux esophagitis in rats

Proinflammatory factors, including neutrophil-derived oxygen free radicals and inflammatory cytokines, have recently been implicated in the pathogenesis of reflux esophagitis. Rebamipide has been widely used as an anti-ulcer agent. The aim of the present study was to assess the protective effect of rebamipide against acute reflux esophagitis in rats. Esophagitis was induced in rats by ligation at the limiting ridge and the lower portion of the duodenum. Vehicle or rebamipide were given as a single dose intraduodenally. Lesion index (LI), thiobarbituric acid-reactive substances (TBA-RS), myeloperoxidase (MPO) activity, mRNA and protein of tumor necrosis factor (TNF)-alpha and cytokine-induced neutrophil chemoattractant (CINC)-1 in the esophageal mucosa were markedly increased; pretreatment with rebamipide, however, significantly reduced both macroscopic and microscopic injuries and increases in inflammatory mediators. The results of this study indicate that rebamipide protects against the occurrence of esophagitis and has highly promising potential as a new therapeutic agent for reflux esophagitis.

Proinflammatory cytokine and nuclear factor kappa-B expression along the inflammation-metaplasia-dysplasia-adenocarcinoma sequence in the esophagus

BACKGROUND

The incidence of esophageal adenocarcinoma has increased significantly in the western world over the last 20 yr. Most cases arise in a background of chronic gastroesophageal reflux, and specialized intestinal metaplasia in Barrett's esophagus is frequently an antecedent phenotype or evident in association with adenocarcinoma. The molecular events that characterize the pathway from inflammation to metaplasia to dysplasia and adenocarcinoma are poorly understood.

AIMS

To examine the expression of the proinflammatory cytokines IL-8 and IL-1beta along the esophagitis, metaplasia, dysplasia, and adenocarcinoma pathway, and to correlate this with histological changes and expression of the transcription factor NF-kappaB.

PATIENTS AND METHODS

Fresh biopsy specimens were collected from patients with reflux esophagitis (n=15), Barrett's esophagus (n=35), Barrett's adjacent to adenocarcinoma (n=8), and esophageal adenocarcinoma (n=35). IL-8 and IL-1beta expression were measured using enzyme-linked immunosorbent assay. NF-kappaB expression was measured by electrophoretic mobility shift assay.

RESULTS

Elevated expression of NF-kappaB was found in 2 (13%) out of 15 patients with reflux esophagitis, 21 (60%) out of 35 patients with Barrett's esophagus, and 28 (80%) out of 35 patients with esophageal adenocarcinoma. All 5 patients with Barrett's esophagus and high-grade dysplasia showed elevated expression of NF-kappaB. IL-8 and IL-1beta were significantly increased in esophagitis, Barrett's, and adenocarcinoma compared with squamous epithelium, and in adenocarcinoma compared with all other groups. There was a stepwise increase in the expression of IL-8, IL-1beta, and NF-kappaB from normal through Barrett's epithelium to adenocarcinoma in eight cases of esophageal adenocarcinoma. The levels of both IL-8 and IL-1beta in adenocarcinoma patients correlated with stage of disease. Patients with adenocarcinoma who were NF-kappaB positive had significantly higher levels of both IL-8 (p=0.04) and IL-1beta (p=0.03) compared to adenocarcinoma patients who were NF-kappaB negative.

CONCLUSIONS

The proinflammatory cytokines IL-8 and IL-1beta are elevated in esophagitis and Barrett's epithelium, and markedly elevated in adenocarcinoma. NF-kappaB activation is infrequent in esophagitis, but is increased in Barrett's epithelium and adenocarcinoma. The association of NF-kappaB activation with cytokine upregulation was only evident in patients with adenocarcinoma. These patterns may play an important role in Barrett's inflammation and tumourigenesis, and inhibition of the NF-kappaB/proinflammatory cytokine pathway may be an important target for future chemoprevention strategies.

Novel antioxidant ameliorates the fibrosis and inflammation of cerulein-induced chronic pancreatitis in a mouse model

BACKGROUND/AIM

Oxygen free radicals (OFRs) mediate an important step in the initiation of experimental acute pancreatitis and several clinical findings suggested the possible contribution of OFRs to the pathogenesis of pancreatic fibrosis. So far, there are no studies which reporting potential role of OFRs in development of chronic pancreatitis with the prevention with antioxidants. This study was aimed to establish the mice model of chronic fibrosing pancreatitis and to prove the involvement of OFRs in chronic pancreatitis with fibrosis.

METHODS

Repeated intraperitoneal cerulein injection was performed to induce chronic pancreatitis in mice. Histological changes in the pancreas were examined, and markers for oxidative stress were measured in the pancreatic tissue and serum of the mice. DA-9601, a phytochemical possessing anti-inflammatory and antioxidative action, was given together with cerulein to the mice.

RESULTS

Repeated intraperitoneal injection of cerulein provoked significant severity of chronic fibrosing pancreatitis after 5 weeks. After treatment of DA-9601, the extents of pancreatic fibrosis were statistically significantly decreased in accordance with lessened pancreatic inflammations. The NF-kappaB binding activities were increased in chronic pancreatitis, which were significantly attenuated after DA-9601 treatment. The levels of myeloperoxidase and iNOS activities were also significantly decreased in DA-9601-treated group compared to the pancreatitis only group. Cytoprotective proteins such as heat shock protein-70 (HSP) and metallothionein were significantly increased in the DA-9601-treated group. DA-9601 decreased the expressions of alpha-SMA and type I collagen in cultured pancreatic stellate cells.

CONCLUSIONS

Oxidative stress was principally involved in the pathogenesis of chronic pancreatitis with fibrosis.

DA-9601 for erosive gastritis: Results of a double-blind placebo-controlled phase III clinical trial

AIM: To determine the efficacy and safety of DA-9601 on erosive gastritis versus cetraxate as a standard drug by gastrointestinal endoscopy.

METHODS: Five hundred and twelve patients with erosive gastritis were divided into three groups. The groups received 180 mg or 360 mg of DA-9601, or 600 mg of cetraxate (Neuer^TM) t.i.d. for 2 wk, respectively. Endoscopic observations were performed before and 2 wk after the treatment, and the cure and improvement rates were investigated.

RESULTS: Of the 512 intention-to-treat (ITT) population, 457 patients comprised the per protocol (PP) analysis. Endoscopic cure rate was significantly higher in the DA-9601 group than in the cetraxate group in both the PP (56%, 58% vs 36%; DA-9601 180 mg, 360 mg and cetraxate, respectively) and ITT (52%, 51% vs 35%) populations. Two DA-9601 groups (180 and 360 mg) had significantly higher endoscopic improvement rates than the cetraxate group in both the PP (67%, 65% vs 46%) and ITT (63%, 58% vs 45%) populations. The percentage of symptom relief over the 2 wk was found not significantly different between groups. During the study, both DA-9601 and cetraxate produced no treatment-associated adverse events.

CONCLUSION: From these results, it appears that DA-9601 has excellent efficacy on erosive gastritis. This study also confirms the safety profile of DA-9601.

Activation of NFkappaB represents the central event in the neoplastic progression associated with Barrett's esophagus: a possible link to the inflammation and overexpression of COX-2, PPARgamma and growth factors

The molecular mechanisms responsible for the progression of malignant transformation in Barrett's esophagus (BE) are still poorly understood. This study was undertaken (1) to investigate the gene and protein expression of cyclooxygenase-2 (COX-2), peroxisome proliferator-activated receptor-gamma (PPARgamma), interleukin-8 (IL-8), hepatocyte growth factor (HGF), gastrin, and its receptor (CCK-2) in the Barrett's epithelium; (2) to analyze the activity of NFkappaB in Barrett's esophagus with low-grade dysplasia; and (3) to assess the effects of PPARgamma ligand (ciglitazone) and gastrin on cell proliferation in the cell line derived from esophageal adenocarcinoma (OE-33). COX-2, PPARgamma, IL-8, HGF, gastrin, and CCK-2 expression levels relative to the control gene encoding GAPDH were analyzed by RT-PCR and Western blot in specimens of BE with low-grade dysplasia (n = 20) and compared with that in the normal squamous esophageal mucosa from the middle portion of the esophagus (n = 20). In vitro experiments included the incubation of cell line OE-33 with ciglitazone (1-15 microM) and gastrin (100 nM). NFkappaB activity in biopsies specimens was measured by highly sensitive ELISA. COX-2, PPARgamma, IL-8, HGF, gastrin, and CCK-2 expressions were significantly increased in BE compared with normal squamous esophageal mucosa. NFkappaB activity was significantly upregulated in BE. Ciglitazone inhibited cell proliferation of OE-33 cells as assessed by BrdU and this effect was attenuated partly by gastrin. (1) COX-2, PPARgamma, HGF, gastrin, and its receptor are significantly upregulated in BE, suggesting a possible role for these factors in Barrett's carcinogenesis; (2) the increased NFkappaB activity is probably linked to increased IL-8 and COX-2 expression; and (3) PPARgamma ligands might be useful as a new therapeutic option in the prevention and treatment of Barrett's carcinoma.

Enhanced expression of interleukin-8 and activation of nuclear factor kappa-B in endoscopy-negative gastroesophageal reflux disease

OBJECTIVE

Interleukin-8 (IL-8) mediates neutrophil trafficking via its receptors. Recent studies have shown that IL-8 is likely involved in the development and progression of erosive reflux esophagitis (RE), yet little is known about its implication in endoscopy-negative gastroesophageal reflux disease (GERD). The purpose of this study was to determine IL-8 messenger ribonucleic acid (mRNA) expression levels in endoscopy-negative GERD, along with assessment of nuclear factor kappaB (NF-kappaB) activation, which upregulates IL-8 expression.

METHODS

We studied 31 patients with endoscopy-negative GERD, 15 patients with erosive RE, and 15 asymptomatic controls. Paired biopsy samples were taken from the esophagus 3 cm above the gastroesophageal junction; one biopsy was snap-frozen for measurement of IL-8 mRNA levels by real-time quantitative polymerase chain reaction, and another was formalin-fixed for histopathological evaluation. In nine endoscopy-negative GERD patients, the IL-8 mRNA expression levels were measured before and 8 wk after treatment with lansoprazole. We also sampled additional specimens for NF-kappaB-DNA binding assay and immunohistochemical analyses of NF-kappaB p65 and p50 subunits, IL-8 and specific IL-8 receptor, CXCR-1.

RESULTS

The relative IL-8 mRNA expression levels were significantly higher in esophageal mucosa of patients with endoscopy-negative GERD than those of the controls. The presence of basal zone hyperplasia and intraepithelial neutrophils, histopathological hallmarks of GERD, were associated with higher levels of IL-8 mRNA. Lansoprazole treatment significantly reduced the IL-8 mRNA expression levels. The esophageal epithelium of patients with GERD showed intense immunoreactivity for IL-8, and expressed CXCR-1 antigen. We found NF-kappaB activation in esophageal mucosa in GERD patients and the NF-kappaB subunits were localized predominantly in the nuclei of IL-8-expressing cells.

CONCLUSIONS

Our results demonstrate enhanced mucosal expression of IL-8 in incipient GERD even without mucosal breaks. NF-kappaB activation may be implicated in the pathogenesis in GERD.

Inhibitory effects of DA-9601 on ethanol-induced gastrohemorrhagic lesions and gastric xanthine oxidase activity in rats

The exposure of gastric mucosa to ethanol produces pathological changes such as inflammatory process, hemorrhagic erosions, even acute ulcers. The gastric mucosal lesions accompanied by a significant decrease of gastric blood flow and increase of reactive oxygen species (ROS) implicate a role of xanthine oxidase in ethanol-induced gastric hemorrhagic erosions. DA-9601, a novel antipeptic formulation of extracts of Artemisia asiatica Nakai, was studied for its inhibitory effect on gastric xanthine oxidase activity and type conversion of the enzyme that has a profound role in free radical generation. Intubation of absolute ethanol (4 g/kg) significantly induced gastrohemorrhagic lesions and lipid peroxidation in the rat stomach. Oral administration of DA-9601 at 40 mg/kg body weight significantly reduced ethanol-induced gastric mucosal hemorrhagic lesions and lipid peroxidation, which was proportional to the inhibitory effect of DA-9601 on alcohol-induced xanthine oxidase-type conversion and enzyme activity. The results suggest that alcohol-induced gastric mucosal damage may be, in part, due to the increased activity of xanthine oxidase and type conversion rate of the enzyme and that the preventive effect of DA-9601 on gastrohemorrhagic lesions would result from its inhibitory action against xanthine oxidase and oxidative stress in alcohol-treated rats.

Reflux, Barrett's oesophagus and adenocarcinoma: burning questions

The incidence of oesophageal adenocarcinoma is increasing rapidly in Western populations. Gastro-oesophageal reflux disease is a strong risk factor for both this tumour and the pre-cancerous lesion Barrett's oesophagus, but the underlying disease mechanisms remain unclear. Developing a better understanding of the aetiology and pathogenesis of Barrett's oesophagus, including the induction of DNA damage and genetic alterations, might provide opportunities for improved management of individuals with this disease. This could include a better rationale for screening and surveillance programmes, as well as targeted intervention strategies.

Duodenal reflux produces hyperproliferative epithelial esophagitis--a possible precursor to esophageal adenocarcinoma in the rat

Esophageal reflux of duodenal contents converts a rat nitrosamine esophageal cancer model from squamous cell carcinoma to adenocarcinoma. Further, there was a tendency for male rats to have a higher incidence of cancer than female rats. However, chemical castration with the gonadotropin-releasing hormone analog leuprolide did not protect male or female animals from developing cancer. We have identified an early (6-week) hyperproliferative epithelial cell reaction to duodenal reflux. We carried out experiments to assess the specificity of duodenal reflux in producing the hyperproliferative epithelial precursor lesion. Animals underwent specific surgical procedures to produce esophageal reflux of pure duodenal contents, mixed gastroduodenal, or bland intestinal contents. A hyperproliferative mucosal esophagitis developed in the group with duodenal reflux but not in the other groups. Mucosal thickness in the duodenal reflux group reached seven times that of normal mucosa at 6 weeks. These results suggest that esophageal reflux of duodenal contents plays an important role in the pathogenicity of proliferative esophagitis and the potential development of esophageal adenocarcinoma.

Overview of medical therapy for gastroesophageal disease

The last twenty years have seen an evolution of much improved strategies in the medical treatment of GERD. Current therapy is targeted at acid suppression, to deal with consequences of mucosal injury and afford resolution of symptoms. Given their modest efficacy, there is no longer much support for initial treatment with H2RAs. PPIs have been shown to provide the highest levels of symptom relief and esophageal healing, in addition to preventing relapse and complications. With this class of agents, the clinician is able to prescribe a drug that is as highly effective as surgery for the purpose intended, without worrying about long term sequelae of acid suppression. It appears that patients with extraesophageal GERD must be treated with higher doses of pharmacologic therapy, principally with the PPIs, for longer periods of time to achieve complete relief of symptoms when compared to patients with heartburn and erosive esophagitis. There is still no clear consensus as to whether aggressive acid suppression alters the natural history of Barrett's esophagus. Based on their initial success, it appears that the next generation of evolving medical therapies will continue to play an important role in the management of GERD. The outcome from medical therapy is the standard against which the results of the novel endoscopy anti-reflux treatments will be measured.