Jyh-Chin Yang

Accurate diagnosis of Helicobacter pylori infection by stool antigen test and 6 other currently available tests in children.

Invasive and noninvasive tests have been developed for the diagnosis of Helicobacter pylori infection. Because H pylori infection is acquired in childhood and adolescence, accurate diagnosis of the infection in the pediatric population is important. We conducted a study to compare invasive tests: culture, biopsy urease test, histology, and polymerase chain reaction on gastric biopsy specimens, with noninvasive tests: serology, (13)C-urea breath test, and a new diagnostic modality, stool antigen test to diagnose H pylori infection. A total of 53 children with symptoms were enrolled in this study, and all had completed the 7 diagnostic tests for H pylori. All the diagnostic tests except serology were excellent methods of diagnosing H pylori infection in children; the diagnostic accuracy was as follows: stool antigen test 96.2%, biopsy urease test 96.2%, histology 98.1%, polymerase chain reaction 94.3%, culture 98.1%, (13)C-urea breath test 100%, and serology 84.9%. The stool antigen test, being highly sensitive and specific, will be potentially very helpful in diagnosing H pylori infection in children.

Effective Prevention and Treatment of Helicobacter pylori Infection Using a Combination of Catechins and Sialic Acid in AGS Cells and BALB/c Mice

The increasing emergence of Helicobacter pylori strains resistant to antibiotics may cause unsuccessful treatment. An alternative agent or mixture with anti-H. pylori effect is urgently required to reduce H. pylori infection. We explored the preventive and therapeutic potential of a combination of catechins and sialic acid on H. pylori-infected human gastric cells in vitro and in mice in vivo. We evaluated the anti-H. pylori activity of catechins and/or sialic acid using the agar dilution and checkerboard methods. The effect of catechins and/or sialic acid on H. pylori infection-induced oxidative stress and apoptosis/autophagy in cell culture was explored using an ultrasensitive chemiluminescence analyzer, immunocytochemistry, and Western blotting. Specific pathogen-free BALB/c mice were divided into uninfected control, infected control, pretreated, and post-treated groups. The effects of catechins/sialic acid were determined by histology and immunocytochemistry. The combination of catechins and sialic acid showed synergistic or additive anti-H. pylori activity and significantly reduced inducible nitric oxide synthase expression and Bax/Bcl-2-mediated apoptosis but enhanced Beclin-1-mediated autophagy. All mice infected with H. pylori displayed gastritis and accumulation of 3-nitrotyrosine and 4-hydroxynonenal. Pretreatment with catechins/sialic acid completely prevented H. pylori infection and resulted in normal histology. Post-treatment with catechins/sialic acid decreased the bacterial load and gastritis score and eradicated up to 60% of H. pylori infections in a dose-dependent manner. This is the first demonstration to our knowledge of a nonprobiotic, nonantibiotic treatment that is 100% effective in preventing and has promising possibilities for treating H. pylori infection. Further studies are needed to confirm this result in humans.

Isolation of a Helicobacter pylori protein, FldA, associated with mucosa-associated lymphoid tissue lymphoma of the stomach

BACKGROUND & AIMS The growth of gastric mucosa-associated lymphoid tissue lymphoma (MALToma) seems to depend on the stimulation of Helicobacter pylori. We attempted to identify specific antigen(s) from H. pylori strains associated with MALToma. METHODS Membranous and secreted proteins of H. pylori were compared on sodium dodecyl sulfate-polyacrylamide gel electrophoresis by Western blot using sera from patients with MALToma. RESULTS A 19-kilodalton protein was seen in all strains isolated from patients with MALToma but uncommonly in other strains. The protein was purified and sequenced. Amino acid sequence comparison showed it was an FldA homologue, a putative flavodoxin protein. DNA sequencing in 26 strains revealed that a nucleotide G insertion at position 481 of the fldA gene was more frequently observed in strains associated with MALToma than other strains (9/9 vs. 6/17; P = 0.002). The mutation caused a short truncation. A recombinant protein with this truncation was expressed and tested. Sera of 12 (70.6%) of 17 patients with MALToma were positive for the antibody to the recombinant protein, and 7 (16.7%) of 42 control patients were positive (12/17 vs. 7/42; P < 0.0001). CONCLUSIONS Truncated FldA of H. pylori is associated with gastric MALToma. It may be involved in the pathogenesis of gastric MALToma. Antibody to this antigen could be used as a serological marker of the disease.

High-dose dual therapy is superior to standard first-line or rescue therapy for Helicobacter pylori infection.

BACKGROUND & AIMS The efficacy of treatment of Helicobacter pylori infection has decreased steadily because of increasing resistance to clarithromycin, metronidazole, and levofloxacin. Resistance to amoxicillin is generally low, and high intragastric pH increases the efficacy of amoxicillin, so we investigated whether a combination of a high-dose proton pump inhibitor and amoxicillin (dual therapy) was more effective than standard first-line or rescue therapies in eradicating H pylori. METHODS We performed a large-scale multihospital trial to compare the efficacy of a high-dose dual therapy (HDDT) with that of standard therapies in treatment-naive (n = 450) or treatment-experienced (n = 168) patients with H pylori infection. Treatment-naive patients were randomly assigned to groups given HDDT (rabeprazole 20 mg and amoxicillin 750 mg, 4 times/day for 14 days, group A1), sequential therapy for 10 days (group B1), or clarithromycin-containing triple therapy for 7 days (group C1). Treatment-experienced patients were randomly assigned to groups given HDDT for 14 days (group A2), sequential therapy for 10 days (B2), or levofloxacin-containing triple therapy for 7 days (C2). H pylori infection was detected by using the (13)C-urea breath test. We evaluated factors associated with treatment outcomes. RESULTS In the intention-to-treat analysis, H pylori was eradicated in 95.3% of patients in group A1 (95% confidence interval [CI], 91.9%-98.8%), 85.3% in B1 (95% CI, 79.6%-91.1%), and 80.7% in group C1 (95% CI, 74.3%-87.1%). Infection was eradicated in 89.3% of patients in group A2 (95% CI, 80.9%-97.6%), 51.8% in group B2 (95% CI, 38.3%-65.3%), and 78.6% (95% CI, 67.5%-89.7%) in group C2. The efficacy of HDDT was significantly higher than that of currently recommended regimens, irrespective of CYP2C19 genotype. Bacterial resistance to drugs was associated with treatment failure. There were no significant differences between groups in adverse events or patient adherence. CONCLUSIONS HDDT is superior to standard regimens as empirical first-line or rescue therapy for H pylori infection, with similar safety profiles and tolerability. ClinicalTrials.gov number: NCT01163435.

Treatment of Helicobacter pylori infection: Current status and future concepts

Helicobacter pylori (H. pylori) infection is highly associated with the occurrence of gastrointestinal diseases, including gastric inflammation, peptic ulcer, gastric cancer, and gastric mucosa-associated lymphoid-tissue lymphoma. Although alternative therapies, including phytomedicines and probiotics, have been used to improve eradication, current treatment still relies on a combination of antimicrobial agents, such as amoxicillin, clarithromycin, metronidazole, and levofloxacin, and antisecretory agents, such as proton pump inhibitors (PPIs). A standard triple therapy consisting of a PPI and two antibiotics (clarithromycin and amoxicillin/metronidazole) is widely used as the first-line regimen for treatment of infection, but the increased resistance of H. pylori to clarithromycin and metronidazole has significantly reduced the eradication rate using this therapy and bismuth-containing therapy or 10-d sequential therapy has therefore been proposed to replace standard triple therapy. Alternatively, levofloxacin-based triple therapy can be used as rescue therapy for H. pylori infection after failure of first-line therapy. The increase in resistance to antibiotics, including levofloxacin, may limit the applicability of such regimens. However, since resistance of H. pylori to amoxicillin is generally low, an optimized high dose dual therapy consisting of a PPI and amoxicillin can be an effective first-line or rescue therapy. In addition, the concomitant use of alternative medicine has the potential to provide additive or synergistic effects against H. pylori infection, though its efficacy needs to be verified in clinical studies.

Prevalence and rapid identification of clarithromycin-resistant Helicobacter pylori isolates in children.

BACKGROUND Little is known about the prevalence of antibiotic-resistant Helicobacter pylori infection in children. Culture and antimicrobial susceptibility testing are generally time-consuming and not a routine in many hospitals. OBJECTIVE To investigate the prevalence of clarithromycin-resistant H. pylori strains in children, to identify those isolates via rapid methodology and to examine the severity of gastritis caused by the antibiotic-resistant H. pylori isolates. METHODS Enrolled were 245 children investigated for H. pylori infection by endoscopic examination. The gastric antral specimens were subjected to DNA extraction and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) with primers specific to the H. pylori 23S rRNA gene. Conventional bacterial cultures were performed simultaneously as the diagnostic standard. Minimal inhibitory concentrations of clarithromycin and metronidazole were determined by E test. This was used as a standard to determine the sensitivity and specificity of the above PCR-RFLP assay. The specimens were processed for histologic examination and evaluated by the updated Sydney system. RESULTS H. pylori was isolated in 67 of the 245 children; 12 (18%) of them were clarithromycin-resistant and 6 (9%) were metronidazole-resistant. No difference in histologic examinations was noted between the antibiotic-resistant and -susceptible strains. We performed PCR-RFLP with all 12 clarithromycin-resistant isolates: 10 had a 23S ribosomal RNA A2144G point mutation; 1 had a mixture of an A2143G point mutant and susceptible strains; and 1 had neither of the 2 mutations. CONCLUSIONS The prevalence of clarithromycin-resistant H. pylori isolates in Taiwanese children is 18%. PCR-RFLP had a high sensitivity (92%) and specificity (100%) for the clarithromycin resistance gene mutation determination. The dominant mutation is A2144G. PCR-RFLP provides a rapid and accurate approach to detect clarithromycin-resistant strains within 24 h.

Identification of 14‐3‐3β in human gastric cancer cells and its potency as a diagnostic and prognostic biomarker

Gastric cancer is the second most common cause of cancer deaths worldwide and due to its poor prognosis, it is important that specific biomarkers are identified to enable its early detection. Through 2‐D gel electrophoresis and MALDI‐TOF‐TOF‐based proteomics approaches, we found that 14‐3‐3β, which was one of the proteins that were differentially expressed by 5‐fluorouracil‐treated gastric cancer SC‐M1 cells, was upregulated in gastric cancer cells. 14‐3‐3β levels in tissues and serum were further validated in gastric cancer patients and controls. The results showed that 14‐3‐3β levels were elevated in tumor tissues (n=40) in comparison to normal tissues (n=40; p<0.01), and serum 14‐3‐3β levels in cancer patients (n=145) were also significantly higher than those in controls (n=63; p<0.0001). Elevated serum 14‐3‐3β levels highly correlated with the number of lymph node metastases, tumor size and a reduced survival rate. Moreover, overexpression of 14‐3‐3β enhanced the growth, invasiveness and migratory activities of tumor cells. Twenty‐eight proteins involved in anti‐apoptosis and tumor progression were also found to be differentially expressed in 14‐3‐3β‐overexpressing gastric cancer cells. Overall, these results highlight the significance of 14‐3‐3β in gastric cancer cell progression and suggest that it has the potential to be used as a diagnostic and prognostic biomarker in gastric cancer.

CYP2C19 genotypes in the pharmacokinetics/pharmacodynamics of proton pump inhibitor-based therapy of Helicobacter pylori infection

Importance of the field: Proton pump inhibitors (PPIs) are potent gastric acid inhibitors. Therapies with a PPI and antibiotics are used to cure Helicobacter pylori (H. pylori) infection, which is closely related to many gastrointestinal diseases. Most PPIs are mainly metabolized by cytochrome 2C19 (CYP2C19). The genetic polymorphisms of CYP2C19 may lead to the differences in pharmacokinetics (PK), pharmacodynamics (PD) and clinical efficacy of PPIs. Areas covered in this review: The roles of PPIs on the eradication of H. pylori are summarized. The impact f CYP2C19 polymorphism on the PK and PD of PPIs is addressed and related to the present status of therapy for H. pylori infection. The opinions on the strategy of PPIs-based therapies of H. pylori infection are provided. What the reader will gain: Update the factors that may influence the PPIs-based therapies of H. pylori infection. Take home message: The eradication rates of H. pylori infection are significantly different between patients who are CYP2C19 extensive metabolizers and poor metabolizers, partly because of the differences in the PK and PD of PPIs. Nonetheless, the differences can be improved by adjusting the regimens of PPIs and using antibiotics that have less H. pylori-resistance.

CagA tyrosine phosphorylation in gastric epithelial cells caused by Helicobacter pylori in patients with gastric adenocarcinoma.

Background. Tyrosine phosphorylation of Helicobacter pylori cytotoxin‐associated protein of in gastric epithelial cells is reported. The goals of this study are first to examine the occurrence of CagA tyrosine phosphorylation in H. pylori strains isolated from patients with gastric adenocarcinoma and gastritis, and second to clarify the relationship between the diversity of tyrosine phosphorylation motifs and the presence of CagA tyrosine phosphorylation.

Sialic Acid Rescues Repurified Lipopolysaccharide-Induced Acute Renal Failure via Inhibiting TLR4/PKC/gp91-Mediated Endoplasmic Reticulum Stress, Apoptosis, Autophagy, and Pyroptosis Signaling

Lipopolysaccharides (LPS) through Toll-like receptor 2 (TLR2) and Toll-like receptor 4 (TLR4) activation induce systemic inflammation where oxidative damage plays a key role in multiple organ failure. Because of the neutralization of LPS toxicity by sialic acid (SA), we determined its effect and mechanisms on repurified LPS (rLPS)-evoked acute renal failure. We assessed the effect of intravenous SA (10 mg/kg body weight) on rLPS-induced renal injury in female Wistar rats by evaluating blood and kidney reactive oxygen species (ROS) responses, renal and systemic hemodynamics, renal function, histopathology, and molecular mechanisms. SA can interact with rLPS through a high binding affinity. rLPS dose- and time-dependently reduced arterial blood pressure, renal microcirculation and blood flow, and increased vascular resistance in the rats. rLPS enhanced monocyte/macrophage (ED-1) infiltration and ROS production and impaired kidneys by triggering p-IRE1α/p-JNK/CHOP/GRP78/ATF4-mediated endoplasmic reticulum (ER) stress, Bax/PARP-mediated apoptosis, Beclin-1/Atg5-Atg12/LC3-II-mediated autophagy, and caspase 1/IL-1β-mediated pyroptosis in the kidneys. SA treatment at 30 min, but not 60 min after rLPS stimulation, gp91 siRNA and protein kinase C-α (PKC) inhibitor efficiently rescued rLPS-induced acute renal failure via inhibition of TLR4/PKC/NADPH oxidase gp91-mediated ER stress, apoptosis, autophagy and pyroptosis in renal proximal tubular cells, and rat kidneys. In response to rLPS or IFNγ, the enhanced Atg5, FADD, LC3-II, and PARP expression can be inhibited by Atg5 siRNA. Albumin (10 mg/kg body weight) did not rescue rLPS-induced injury. In conclusion, early treatment (within 30 min) of SA attenuates rLPS-induced renal failure via the reduction in LPS toxicity and subsequently inhibiting rLPS-activated TLR4/PKC/gp91/ER stress/apoptosis/autophagy/pyroptosis signaling.