Safety, tolerability and efficacy of a novel self-use biodegradable device for management of obesity.

OBJECTIVE: Obesity is a major public health issue with significant impact on quality of life, morbidity and mortality rates. It is estimated that if the current trends continue, 18% of men and 21% of women worldwide will be obese by 2025. All the current therapies are not optimal due to limited efficacy or safety; thus, there is a need for additional devices for the treatment of obesity. This study aimed to examine the safety, tolerability, and efficacy of a biodegradable encapsulated Epitomee device for weight loss. The technology is based on absorbent pharmaceuticals polymers and bonding materials that self-expand in the stomach to create a pH-sensitive super absorbent gel structure for weight loss. METHODS: A prospective, 12-week twice daily use of the encapsulated device in patients with body mass index of 27-40 kg m-2. Efficacy endpoints were the percent total body weight loss (%TBWL), proportion of participants with 5% TBWL and changes in cardio-metabolic markers. Safety analysis included evaluation of adverse events, laboratory and endoscopic findings. RESULTS: Overall, 52 patients completed the study. TBWL per intension-to-treat analysis was 3.68 ± 3.07% (3.23 ± 2.69 kg) and 4.52 ± 2.97% (3.95 ± 2.57 kg) per protocol. No device serious adverse effects reported. The most common adverse events were headache (18.1%), viral infection (11.5%), abdominal discomfort (10.1%), bloating (7.9%), nausea and constipation (5% each) and flatulence (4.3%). Endoscopy in 26 patients revealed mild, asymptomatic gastric/duodenal erythema without erosions in five patients. CONCLUSIONS: Twelve weeks of Epitomee capsules treatment combined with lifestyle counselling resulted in 3.68-4.52% of TBWL. With continued research, the Epitomee capsules have considerable potential to become a non-invasive, safe and effective treatment option for weight loss.

Promotion of cytoplasmic mislocalization of p27 by Helicobacter pylori in gastric cancer.

The cyclin-dependent kinase (CDK) inhibitor p27 has an important role in cell cycle regulation. Reduced expression of p27 is commonly associated with poor prognosis in many malignancies, including gastric cancer. Cytoplasmic p27 mislocalization may be an additional indicator of high-grade tumors and poor prognosis in cancer. As chronic infection by Helicobacter pylori is the most important risk factor for gastric cancer development, we evaluated the effects of H. pylori on p27 expression and localization in gastric cancer cells. Co-culture of gastric cells with H. pylori induced cytoplasmic p27 expression and reduced nuclear p27 expression in vitro. Cytoplasmic p27 expression was associated with and dependent upon phosphorylation of p27 at T157 and T198: wild-type p27 accumulated in the cytoplasm, but non-phosphorylatable mutants affecting T157 or T198 were nuclear in H. pylori-infected cells. These post-translational p27 changes were secondary to activation of cellular phosphoinositide-3 kinase (PI3K) and AKT signaling pathways, and dependent upon a functional H. pylori cag pathogenicity island. We investigated the clinical significance of cytoplasmic p27 mislocalization in 164 cases of resected gastric cancer in tissue microarrays. In 97 cases (59%), cytoplasmic p27 mislocalization was observed, and this was associated with increased mortality in multivariate analysis. These results show that H. pylori infection induces AKT/PI3K-mediated phosphorylation of p27 at T157 and T198 to cause cytoplasmic p27 mislocalization in gastric cancer, and that p27 mislocalization is an adverse prognostic feature in gastric cancer. This is the first demonstration of the translocation of a specific bacterial virulence factor that post-translationally regulates a host cell CDK inhibitor. This is of particular significance, because p27 has both tumor-suppressive and oncogenic activities, depending upon its subcellular localization. Cytoplasmic mislocalization of p27 induced by H. pylori may be an important mechanistic link between H. pylori infection and gastric carcinogenesis.

Diagnosis and management of non-erosive reflux disease--the Vevey NERD Consensus Group.

BACKGROUND/AIMS: Although considerable information exists regarding gastroesophageal reflux disease with erosions, much less is known of non-erosive reflux disease (NERD), the dominant form of reflux disease in the developed world. METHODS: An expert international group using the modified Delphi technique examined the quality of evidence and established levels of agreement relating to different aspects of NERD. Discussion focused on clinical presentation, assessment of clinical outcome, pathobiological mechanisms, and clinical strategies for diagnosis and management. RESULTS: Consensus was reached on 85 specific statements. NERD was defined as a condition with reflux symptoms in the absence of mucosal lesions or breaks detected by conventional endoscopy, and without prior effective acid-suppressive therapy. Evidence supporting this diagnosis included: responsiveness to acid suppression therapy, abnormal reflux monitoring or the identification of specific novel endoscopic and histological findings. Functional heartburn was considered a separate entity not related to acid reflux. Proton pump inhibitors are the definitive therapy for NERD, with efficacy best evaluated by validated quality-of-life instruments. Adjunctive antacids or H(2) receptor antagonists are ineffective, surgery seldom indicated. CONCLUSIONS: Little is known of the pathobiology of NERD. Further elucidation of the mechanisms of mucosal and visceral hypersensitivity is required to improve NERD management.

Intestinal necrosis due to sodium polystyrene sulfonate (Kayexalate) in sorbitol.

BACKGROUND: Sodium polystyrene sulfonate (SPS, Kayexalate) has been implicated in the development of intestinal necrosis. Sorbitol, added as a cathartic agent, may be primarily responsible. Previous studies have documented bowel necrosis primarily in postoperative, dialysis, and transplant patients. We sought to identify additional clinical characteristics among patients with probable SPS-induced intestinal necrosis. METHODS: Rhode Island Hospital surgical pathology records were reviewed to identify all gastrointestinal specimens reported as containing SPS crystals from December 1998 to June 2007. Patient demographics, medical comorbidities, and hospital courses of histologically verified cases of intestinal necrosis were extracted from the medical records. RESULTS: Twenty-nine patients with reports of SPS crystals were identified. Nine cases were excluded as incidental findings with normal mucosa. Nine patients were excluded as their symptoms began before SPS administration or because an alternate etiology for bowel ischemia was identified. Eleven patients had confirmed intestinal necrosis and a temporal relationship with SPS administration suggestive of SPS-induced necrosis. Only 2 patients were postoperative, and only 4 had end-stage renal disease (ESRD). All patients had documented hyperkalemia, received oral SPS, and developed symptoms of intestinal injury between 3 hours and 11 days after SPS administration. Four patients died. CONCLUSION: Intestinal ischemia is a recognized risk of SPS in sorbitol. Our series highlights that patients may be susceptible even in the absence of ESRD, surgical intervention, or significant comorbidity.

Review article: RNA interference--potential therapeutic applications for the gastroenterologist.

BACKGROUND: A new technique of gene regulation, termed RNA interference, has emerged recently. RNA interference utilizes short double-stranded RNA to inhibit selectively gene expression of complementary RNA nucleotide sequences after transcription, but prior to translation. Gastrointestinal and hepatic disorders may be particularly amenable to therapeutic RNA interference intervention because of the relative ease of delivery of drugs to the gastrointestinal tract and liver. AIM: To examine the published literature for potential clinical uses of RNA interference in gastroenterology and speculate on future therapies for luminal disease. METHODS: Reports were identified using PubMed and the search term 'RNA interference', focusing on therapeutic uses related to gastrointestinal and liver disease. RESULTS: Cellular and animal models demonstrate the potential application of short-interfering RNA-based therapies for viral hepatitis and inflammatory bowel disease. With validation of specific targets and better in vivo delivery of short-interfering RNA, RNA interference may represent a new frontier for molecular-targeted therapy in gastroenterology and hepatology. CONCLUSIONS: Short-interfering RNA provides a novel and specific means to inhibit gene expression. Translation to the clinical arena will require further definition of side-effects, off-target effects and delivery systems. Ultimately, mucosally applied or endoscopically delivered short-interfering RNA could be one of the earliest clinical uses of short-interfering RNA therapy.

Global analysis of the human gastric epithelial transcriptome altered by Helicobacter pylori eradication in vivo.

OBJECTIVE: The transcriptional profile of gastric epithelial cell lines cocultured with Helicobacter pylori and the global gene expression of whole gastric mucosa has been described previously. We aimed to overcome limitations of previous studies by determining the effects of H pylori eradication on the transcriptome of purified human gastric epithelium using each patient as their own control. DESIGN: Laser capture microdissection (LCM) was used to extract mRNA from paraffin-embedded antral epithelium from 10 patients with peptic ulcer disease, before and after H pylori eradication. mRNA was reverse transcribed and applied on to Affymetrix cDNA microarray chips customised for formalin-fixed tissue. Differentially expressed genes were identified and a subset validated by real-time polymerase chain reaction (PCR). RESULTS: A total of 13 817 transcripts decreased and 9680 increased after H pylori eradication. Applying cut-off criteria (p<0.02, fold-change threshold 2.5) reduced the sample to 98 differentially expressed genes. Genes detected included those previously implicated in H pylori pathophysiology such as interleukin 8, chemokine ligand 3, beta defensin and somatostatin, as well as novel genes such as GDDR (TFIZ1), chemokine receptors 7 and 8, and gastrokine. CONCLUSIONS: LCM of archival specimens has enabled the identification of gastric epithelial genes whose expression is considerably altered after H pylori eradication. This study has confirmed the presence of genes previously implicated in the pathogenesis of H pylori, as well as highlighted novel candidates for further investigation.

Review article: from gastrin to gastro-oesophageal reflux disease--a century of acid suppression.

To commemorate Edkins' discovery of gastrin in 1905, we review a century of progress in the physiology and pathobiology of gastrin and acid secretion especially as it pertains to clinical aspects of gastro-oesophageal reflux disease. Although initially ignored, Edkins' observations eventually led to the enthusiastic investigation of gastrin and acid regulation in peptic ulcer disease, culminating in important therapeutic advances in the management of acid peptic disease. Following the improved understanding of gastric secretory physiology, and the development of acid suppressants with increasing efficacy, the use of surgical intervention for peptic ulcer disease was almost eliminated. Surgery became obsolete with the discovery of Helicobacter pylori. Three other advances are also influencing modern practice: the gastrotoxicity of aspirin and non-steroidal anti-inflammatory drugs is now increasingly appreciated, the role of endoscopy in the diagnosis and therapy of upper gastrointestinal bleeding, and the use of intravenous acid-suppressive agents. The major issue for the future resides within the epidemic of gastro-oesophageal reflux disease. How to diagnose, categorize and treat this condition and how to identify and prevent neoplasia, are the challenges of the new century.

Masking of 13C urea breath test by proton pump inhibitors is dependent on type of medication: comparison between omeprazole, pantoprazole, lansoprazole and esomeprazole.

BACKGROUND: The need to withhold acid suppression therapy while awaiting urea breath test results is a common clinical problem in symptomatic patients. It is unclear at present if the dose or type of proton pump inhibitor or the type of test meal govern the apparent masking effect of proton pump inhibitors on the urea breath test. AIM: To prospectively evaluate Helicobacter pylori detection rates during treatment with four different proton pump inhibitors, utilizing a high-dose citric acid-based 13C urea breath test. METHODS: Patients positive for Helicobacter pylori by urea breath test were randomized to receive either omeprazole 20 mg/day, pantoprazole 40 mg/day, lansoprazole 30 mg/day or esomeprazole 40 mg/day for 14 days. A repeat breath test was performed on day 14 of treatment. RESULTS: One hundred and seventy-nine patients, mean age 45.8 +/- 16.8, completed the study. Treatment with omeprazole or pantoprazole prior to urea breath test (UBT) was associated with low false negative results, while lansoprazole and esomeprazole caused clinically unacceptable high false negative rates (pantoprazole 2.2% vs. lansoprazole 16.6%, P = 0.02, vs. esomeprazole 13.6%, P = 0.05; omeprazole 4.1% vs. lansoprazole 16.6%, P = 0.05). CONCLUSIONS: Proton pump inhibitor-induced false negative results on high-dose citric acid based urea breath test vary with the type of proton pump inhibitor used. Selection of the appropriate test meal and proton pump inhibitor may allow symptomatic individuals to continue their proton pump inhibitors prior to performing a urea breath test.

P27kip1 regulates the apoptotic response of gastric epithelial cells to Helicobacter pylori.

BACKGROUND: Helicobacter pylori infection increases the risk of gastric cancer but the molecular mechanisms responsible are not well understood. Gastric cells chronically exposed to H pylori in vitro develop resistance to apoptosis associated with low levels of p27, a cyclin dependent kinase inhibitor and haplo insufficient tumour suppressor gene that is downregulated in gastric cancer. AIM: To determine whether the low level of p27 protein is responsible for the resistance to apoptosis of gastric cancer cells. METHODS: The effects of increasing the expression of p27 protein were examined by transiently and stably transfecting a plasmid encoding full length p27 mRNA into apoptosis resistant gastric cancer cell lines with low p27 expression that were derived from AGS gastric cancer cells by chronic H pylori coculture followed by dilutional cloning. RESULTS: Low p27 expression in the apoptosis resistant derivative cell lines was associated with an approximate 30% decrease in p27 mRNA and an 80% decrease in p27 protein that was not due to increased proteasome dependent degradation of p27 protein. Transient or stable transfection with p27 constructs partially restored the sensitivity of the apoptosis resistant cells to 5-fluorouracil and H pylori induced apoptosis without altering spontaneous apoptotic cell death. CONCLUSIONS: These results demonstrate that p27 positively regulates, at least in part, the apoptotic response of gastric epithelial cells to H pylori. Low gastric p27 may promote gastric carcinogenesis associated with H pylori infection by inhibiting apoptotic pathways.

Effects of H. pylori infection of gastric epithelial cells on cell cycle control.

Chronic infection of the gastric mucosa by the bacterium H. pylori results in an intense inflammatory response which can last for decades. An associated host response is a chronic hyperproliferative state, in which there is increased cell turnover and also increased apoptosis of the gastric epithelial cells. Recent studies have also demonstrated abnormalities in the expression of cell cycle control proteins. This review describes these events, emphasizing recent studies on the effects of H. pylori infection on cell cycle progression and the expression of cell cycle regulatory proteins. The systems that have been studied include in vivo studies in humans and in experimental animals, and in vitro studies in which gastric epithelial cells were co-cultivated with H. pylori. The earliest event following H. pylori's interaction with epithelial cells appears to be growth inhibition and apoptosis. The hyperproliferative response observed in the gastric mucosa is secondary to this initial insult and is associated with increased expression of cyclin D1, the cyclin dependent kinase inhibitor p16ink4a and of p53 and decreased expression of the cyclin dependent kinase inhibitor p27kip1. Dysregulation of the hyperproliferative response may, ultimately, be responsible for the ability of H. pylori to enhance the development of gastric cancer.

Novel (4-piperazin-1-ylquinolin-6-yl) arylsulfonamides with high affinity and selectivity for the 5-HT(6) receptor.

The discovery of (4-piperazin-1-ylquinolin-6-yl) arylsulfonamides and their binding affinities for a selection of 5-HT and dopamine subreceptors is described. Many compounds show high affinity (pK(i)>8) for the 5-HT(6) receptor and >100-fold selectivity against a range of other receptors. Structure-activity relationships of these compounds are discussed.

Effect of ectopic expression of rat trefoil factor family 3 (intestinal trefoil factor) in the jejunum of transgenic mice.

To further examine the function of the trefoil factor family (TFF), the expression of which is up-regulated at sites of injury, we have produced transgenic mice that chronically express rat TFF3 within the jejunum (using a rat fatty acid-binding protein promoter). The expression of rat TFF3 was limited to the villi of the jejunum and had no effect on base-line morphology. Rat TFF3 expression did result, however, in a reduced sensitivity to indomethacin (85 mg/kg subcutaneously), which only caused a 29% reduction in villus height in transgenics versus 51% reduction in controls (p < 0.01). Indomethacin increased initial intestinal epithelial cell proliferation and migration, but the presence of rat TFF3 caused no additional change in proliferation (bromodeoxyuridine), cell migration ([(3)H]thymidine and bromodeoxyuridine), apoptosis (terminal deoxyuridine nucleotidyl nick end labeling), or E-cadherin immunostaining. In vitro studies following changes in resistance of intestinal strips in Ussing chambers (voltage-clamp technique) showed increased base-line resistance in the rat TFF3-expressing region (326 +/- 60 versus 195 +/- 48 ohm.cm(2) in controls, p < 0.05) and reduced the fall in resistance following HCl exposure by about 40% (p < 0.01). Overexpression of TFF3 stabilizes the mucosa against noxious agents, supporting its role in mucosal protection/repair. It may therefore provide a novel approach to the prevention and/or treatment of intestinal ulceration.

Increased gastric epithelial cell apoptosis associated with colonization with cagA + Helicobacter pylori strains.

Gastric colonization by Helicobacter pylori is a risk factor for noncardia gastric cancer. The association between H. pylori and cancer may be attributable to increased epithelial cell turnover, possibly related to antigastric antibodies. Two previous studies reported a disproportionate increase in proliferation relative to apoptosis in patients with H. pylori strains expressing the virulence-related cagA gene. This has led to the hypothesis that an abrogation of apoptosis by cagA-positive strains may promote neoplasia. We, therefore, examined the effect of H. pylori on gastric epithelial proliferation, apoptosis, and the presence of serum antiparietal cell antibodies in a large prospective study. Proliferation and apoptosis were evaluated "blindly" using validated immunohistochemical methods in two antral and two gastric corpus biopsies from 60 patients with nonulcer dyspepsia, and results were correlated with the presence of serum antiparietal cell antibodies. H. pylori colonization was assessed by histology, biopsy urease test, and serology. Proliferation was increased 2-fold in both antrum and corpus in H. pylori-positive patients, was not related to H. pylori cagA status, and was positively correlated with histological gastritis. Apoptosis was increased in the antrum and body only in patients with cagA-positive H. pylori strains. Antiparietal cell antibodies were not more prevalent in H. pylori colonization, and their presence was inversely related to epithelial apoptosis scores we therefore conclude that in patients with nonulcer dyspepsia, H. pylori carriage is associated with increased proliferation. Futhermore the cag pathogenicity island is associated with increased apoptosis. Our results do not support the hypothesis that there is a relative deficiency of gastric epithelial cell apoptosis associated with the carriage of cagA-positive strains. Host factors may be more important than bacterial products in determining the long-term outcome of H. pylori colonization.

Helicobacter pylori strain-specific differences in genetic content, identified by microarray, influence host inflammatory responses.

Helicobacter pylori enhances the risk for ulcer disease and gastric cancer, yet only a minority of H. pylori-colonized individuals develop disease. We examined the ability of two H. pylori isolates to induce differential host responses in vivo or in vitro, and then used an H. pylori whole genome microarray to identify bacterial determinants related to pathogenesis. Gastric ulcer strain B128 induced more severe gastritis, proliferation, and apoptosis in gerbil mucosa than did duodenal ulcer strain G1.1, and gastric ulceration and atrophy occurred only in B128+ gerbils. In vitro, gerbil-passaged B128 derivatives significantly increased IL-8 secretion and apoptosis compared with G1.1 strains. DNA hybridization to the microarray identified several strain-specific differences in gene composition including a large deletion of the cag pathogenicity island in strain G1.1. Partial and complete disruption of the cag island in strain B128 attenuated induction of IL-8 in vitro and significantly decreased gastric inflammation in vivo. These results indicate that the ability of H. pylori to regulate epithelial cell responses related to inflammation depends on the presence of an intact cag pathogenicity island. Use of an H pylori whole genome microarray is an effective method to identify differences in gene content between H. pylori strains that induce distinct pathological outcomes in a rodent model of H. pylori infection.

Helicobacter pylori decreases gastric mucosal glutathione.

Activation of oxidative stress pathways may contribute to gastric epithelial damage and mutagenesis caused by Helicobacter pylori. We measured the effect of H. pylori on the concentrations of reduced glutathione (GSH), an important endogenous defense against oxidant damage, in gastric epithelial cells in vivo and in vitro. GSH concentrations were significantly lower in gastric biopsies from 19 H. pylori-infected patients than 38 normal controls, and correlated inversely with inflammatory cell numbers. In vitro, H. pylori initially increased GSH levels in AGS cells, but subsequently depleted intracellular GSH stores completely after 24 h. No GSH was detected in H. pylori. Our data suggest that diminished GSH levels with H. pylori colonization of the gastric mucosa may be due to a direct effect of the bacterium as well as through the associated inflammatory response.

Antiproliferative effects of S-allylmercaptocysteine on colon cancer cells when tested alone or in combination with sulindac sulfide.

Epidemiological studies link increased garlic (Allium sativum) consumption with a reduced incidence of colon cancer in various human populations. Experimental carcinogenesis studies in animal models and in cell culture systems indicate that several allium-derived compounds exhibit inhibitory effects and that the underlying mechanisms may involve both the initiation and promotion phases of carcinogenesis. To provide a better understanding of the effects of allium derivatives on the prevention of colon cancer, we examined two water-soluble derivatives of garlic, S-allylcysteine (SAC) and S-allylmercaptocysteine (SAMC), for their effects on proliferation and cell cycle progression in two human colon cancer cell lines, SW-480 and HT-29. For comparison, we included the compound sulindac sulfide (SS), because sulindac compounds are well-established colon cancer chemopreventive agents. We found that SAMC, but not SAC, inhibited the growth of both cell lines at doses similar to that of SS. SAMC also induced apoptosis, and this was associated with an increase in caspase3-like activity. These affects of SAMC were accompanied by induction of jun kinase activity and a marked increase in endogenous levels of reduced glutathione. Although SS caused inhibition of cell cycle progression from G1 to S, SAMC inhibited progression at G2-M, and a fraction of the SW-480 and HT-29 cells were specifically arrested in mitosis. Coadministration of SS with SAMC enhanced the growth inhibitory and apoptotic effects of SS. These findings suggest that SAMC may be useful in colon cancer prevention when used alone or in combination with SS or other chemopreventive agents.