Cholesterol glucosylation-based survival strategy in Helicobacter pylori

Antihyperlipidemic drugs mitigate the elevated incidence of peptic ulcer disease caused by hyperlipidemia: A cohort study

BACKGROUND

Several risk factors for peptic ulcer disease (PUD) have been identified; however, the recurrence rate of PUD remains high even with standard ulcer treatments. High cholesterol levels have been proposed as a risk factor for PUD, but clinical evidence remains limited. Therefore, this database study investigated whether hyperlipidemia increases PUD risk and whether antihyperlipidemic drugs reduce this risk.

METHODS

A long-term cohort design was adopted, and Taiwan's National Health Insurance Research Database was used to enroll patients diagnosed with hyperlipidemia between 2000 and 2016. Patients without hyperlipidemia were randomly matched based on variables such as age and gender to establish a comparison cohort at a 1:1 ratio. Another cohort study was conducted to determine whether antihyperlipidemic drugs or red yeast rice prescriptions can reduce the incidence of PUD in patients with hyperlipidemia.

RESULTS

The overall incidence of PUD was 1.48 times higher in the hyperlipidemia cohort (203,235 patients) than in the nonhyperlipidemia cohort (adjusted hazard ratio, 1.48; 95% CI, 1.46-1.50; p < 0.001). Among the patients with hyperlipidemia, those who used antihyperlipidemic drugs with or without red yeast rice prescriptions exhibited a lower risk of developing PUD relative to those who did not use them; the adjusted hazard ratios were 0.33 (95% CI, 0.21-0.52) and 0.81 (95% CI, 0.78-0.84), respectively. When the cumulative exposure to antihyperlipidemic drugs and red yeast rice prescriptions increased, the risk of developing PUD showed a decreasing trend, which was statistically significant for antihyperlipidemic drugs but not for red yeast rice.

CONCLUSION

Hyperlipidemia is associated with a higher risk of PUD, which can be reduced through the administration of antihyperlipidemic drugs with or without red yeast rice prescriptions.

[Viable Bacteria Assay of Helicobacter pylori by RT-qPCR Measurement of cgt Gene Expression Levels: Establishment and Application of a New Method]

Objective

To establish a viable bacteria assay for Helicobacter pylori (H. pylori) by assessing the cgt gene expression, and to develop accordingly a rapid and novel testing method for clinical precision treatment.

Methods

Viable bacteria count was determined in bacterial cultures. The transcriptional expression level of cgt (hp0421), the conserved gene that encodes cholesterol-α-glucosyltransferase (CGT) in H. pylori, was measured by RT-PCR. The correlation between the number of colonies and cgt gene transcription expression was analyzed and the regression model was constructed. The linear range, sensitivity, and specificity of the new method were examined accordingly. The bactericidal action of clarithromycin was assessed using this method to verify the performance of the method in determining clinical bacterial drug resistance.

Results

The Ct values of cgt for H. pylori colony counts of 102, 104, 106, and 108 CFU/mL were 29.67±0.14, 23.37±0.36, 17.65±0.37, and 11.38±0.39, respectively. In the range of 101-108 CFU/mL, the regression equation for cgt gene expression and viable bacterial counts determined by RT-qPCR was y=-0.3501x+12.49, with the correlation coefficient being R 2=0.9992 and the sensitivity being 101 CFU/mL, showing no cross-reaction with 13 other bacteria. The lg values of live H. pylori bacteria treated with clarithromycin at 0, 5, 10, 20, and 40 μg/mL for 12 h were 2.57±0.02, 2.45±0.01, 2.19±0.02, 1.91±0.07, and 1.33±0.05, respectively. The corresponding cgt gene Ct values were 27.76±0.09, 28.37±0.24, 29.51±0.14, 30.11±0.12, and 31.66±0.11. By applying the cgt gene expression in the equation, the estimated counts of viable bacteria were found to be 2.73±0.03, 2.52±0.08, 2.11±0.05, 1.89±0.02, and 1.33±0.04, showing no significant difference in statistical analysis (P>0.05).

Conclusion

The method for assessing viable bacteria account by evaluating cgt gene expression in H. pylori was successfully established, significantly reducing the time required to determine viable bacteria count and providing a new method for clinical viable bacteria testing.

Current research on the interaction between Helicobacter pylori and macrophages

Helicobacter pylori (H. pylori) is a gram-negative bacteria with a worldwide infection rate of 50%, known to induce gastritis, ulcers and gastric cancer. The interplay between H. pylori and immune cells within the gastric mucosa is pivotal in the pathogenesis of H. pylori-related disease. Following H. pylori infection, there is an observed increase in gastric mucosal macrophages, which are associated with the progression of gastritis. H. pylori elicits macrophage polarization, releases cytokines, reactive oxygen species (ROS) and nitric oxide (NO) to promote inflammatory response and eliminate H. pylori. Meanwhile, H. pylori has developed mechanisms to evade the host immune response in order to maintain the persistent infection, including interference with macrophage phagocytosis and antigen presentation, as well as induction of macrophage apoptosis. Consequently, the interaction between H. pylori and macrophages can significantly impact the progression, pathogenesis, and resolution of H. pylori infection. Moreover, macrophages are emerging as potential therapeutic targets for H. pylori-associated gastritis. Therefore, elucidating the involvement of macrophages in H. pylori infection may provide novel insights into the pathogenesis, progression, and management of H. pylori-related disease.

Cell lipid biology in infections: an overview

Lipids are a big family of molecules with a vast number of functions in the cell membranes, within the cytoplasm, and extracellularly. Lipid droplets (LDs) are the most common storage organelles and are present in almost every tissue type in the body. They also have structural functions serving as building blocks of cellular membranes and may be precursors of other molecules such as hormones, and lipoproteins, and as messengers in signal transduction. Fatty acids (FAs), such as sterol esters and triacylglycerols, are stored in LDs and are used in β-oxidation as fuel for tricarboxylic acid cycle (TCA) and adenosine triphosphate (ATP) generation. FA uptake and entrance in the cytoplasm are mediated by membrane receptors. After a cytoplasmic round of α- and β-oxidation, FAs are guided into the mitochondrial matrix by the L-carnitine shuttle system, where they are fully metabolized, and enter the TCA cycle. Pathogen infections may lead to impaired lipid metabolism, usage of membrane phospholipids, and LD accumulation in the cytoplasm of infected cells. Otherwise, bacterial pathogens may use lipid metabolism as a carbon source, thus altering the reactions and leading to cellular and organelles malfunctioning. This review aims to describe cellular lipid metabolism and alterations that occur upon infections.

Inhibitory and Injury-Protection Effects of O-Glycan on Gastric Epithelial Cells Infected with Helicobacter pylori

Helicobacter pylori (H. pylori) is an important pathogen that can cause gastric cancer. Multiple adhesion molecules mediated H. pylori adherence to cells is the initial step in the infection of host cells. H. pylori cholesterol-α-glucosyltransferase (CGT) recognizes and extracts cholesterol from cell membranes to destroy lipid raft structure, further promotes H. pylori adhesion to gastric epithelial cells. O-Glycan, a substance secreted by the deep gastric mucosa, can competitively inhibit CGT activity and may serve as an important factor to prevent H. pylori colonization in the deep gastric mucosa. However, the inhibitory and injury-protection effects of O-Glycan against H. pylori infection has not been well investigated. In this study, we found that O-Glycan significantly inhibited the relative urease content in the coinfection system. In the presence of O-glycan, the injury of GES-1 cells in H. pylori persistent infection model was attenuated and the cell viability was increased. We use fluorescein isothiocyanate-conjugated cholera toxin subunit B (FITC-CTX-B) to detect lipid rafts on gastric epithelial cells and observed that O-glycan can protect H. pylori from damaging lipid raft structures on cell membranes. In addition, transcriptome data showed that O-glycan treatment significantly reduced the activation of inflammatory cancer transformation pathway caused by H. pylori infection. Our results suggest that O-Glycan is able to inhibit H. pylori persistent infection of gastric epithelial cells, reduce the damage caused by H. pylori, and could serve as a potential medicine to treat patients infected with H. pylori.

Exosomal CagA from Helicobacter pylori aggravates intestinal epithelium barrier dysfunction in chronic colitis by facilitating Claudin-2 expression

BACKGROUND

The chronic infection with Helicobacter pylori (H. pylori), especially cytotoxin-associated gene A-positive (CagA⁺) strains, has been associated with various extragastric disorders. Evaluating the potential impacts of virulence factor CagA on intestine may provide a better understanding of H. pylori pathogenesis such as colitis. The intestinal mucosal barrier is essential for maintaining its integrity and functions. However, how persistent CagA⁺ H. pylori colonization influences barrier disruption and thereby affects chronic colitis is not fully understood.

RESULTS

Chronic colitis models of CagA⁺ H. pylori-colonized mice treated with 2% Dextran sulphate sodium (DSS) were established to assess the disease activity and pertinent expression of tight junction proteins closely related to mucosal integrity. The aggravating effect of CagA⁺ H. pylori infection on DSS-induced chronic colitis was confirmed in mouse models. In addition, augmented Claudin-2 expression was detected in CagA⁺ H. pylori infection conditions and selected for mechanistic analysis. Next, GES-1 human gastric epithelial cells were cultured with CagA⁺ H. pylori or a recombinant CagA protein, and exosomes isolated from conditioned media were then identified. We assessed the Claudin-2 levels after exposure to CagA⁺ exosomes, CagA^- exosomes, and IFN-γ incubation, revealing that CagA⁺ H. pylori compromised the colonic mucosal barrier and facilitated IFN-γ-induced intestinal epithelial destruction through CagA-containing exosome-mediated mechanisms. Specifically, CagA upregulated Claudin-2 expression at the transcriptional level via a CDX2-dependent mechanism to slow the restoration of wounded mucosa in colitis in vitro.

CONCLUSIONS

These data suggest that exosomes containing CagA facilitate CDX2-dependent Claudin-2 maintenance. The exosome-dependent mechanisms of CagA⁺ H. pylori infection are indispensable for damaging the mucosal barrier integrity in chronic colitis, which may provide a new idea for inflammatory bowel disease (IBD) treatment.

Emerging Trends and their Impacts on Peptic Ulcer Diseases: Treatments and Techniques

Background:

Peptic ulcer disease (PUD) is prevalent in almost all parts of the world. PUD complications are creating a major source of preventable health care expenses. The major factors responsible for the incidence of PUD and its complication have changed over the past few decades after the identification of non-steroidal inflammatory drugs (NSAIDs) and Helicobacter pylori bacterial infection along with a marked increase in the use of proton-pump inhibitors (PPIs) as drug therapy. The management of PUD has become more complex and challenging due to antimicrobial resistance.

Objective:

The objective of the study was to highlight current therapy and novel techniques used in the treatment of peptic ulcer diseases.

Methods:

An exhaustive literature search has been conducted across PubMed, Google, Scopus and Web of Science as an electronic database to add the crucial information from the relevant literature.

Results:

In the present review, we have discussed PUD and its pathophysiology. The recent trends in PUD and possible treatments with novel techniques have also been discussed. The type and presence of ulcers cannot be predicted accurately based on symptoms. The available treatment approaches for peptic ulcers based on their clinical presentation and etiology are anti-secretary therapy, endoscopy to reveal ulcers followed by drug therapy, and triple therapy for H pylori infection.

Conclusion:

Thus, the popular and effective methods are very beneficial in controlling PUD. The treatment based on diagnosis is the foremost requirement for ameliorating any disorder. In this article, the emerging techniques and development in the treatment and diagnosis of PUD have been reviewed.

Immunological Perspective: Helicobacter pylori Infection and Gastritis

Helicobacter pylori is a spiral-shaped gram-negative bacterium. Its infection is mainly transmitted via oral-oral and fecal-oral routes usually during early childhood. It can achieve persistent colonization by manipulating the host immune responses, which also causes mucosal damage and inflammation. H. pylori gastritis is an infectious disease and results in chronic gastritis of different severity in near all patients with infection. It may develop from acute/chronic inflammation, chronic atrophic gastritis, intestinal metaplasia, dysplasia, and intraepithelial neoplasia, eventually to gastric cancer. This review attempts to cover recent studies which provide important insights into how H. pylori causes chronic inflammation and what the characteristic is, which will immunologically explain H. pylori gastritis.

Genome Dynamics and Evolution of Multiple-Drug-Resistant Bacteria: Implications for Global Infection Control Priorities

Genomics-driven molecular epidemiology of pathogenic bacteria has largely been carried out through functionally neutral/inert sequences, mostly entailing polymorphic gene loci or repetitive tracts. However, it is very important to harness phenotypically relevant markers to assign a valid functional epidemiological context to tracking of pathogens. These should include microbial acumen to acquire multiple drug resistance (MDR), their physiological coordinates with reference to clinical or community-level dynamics of incidence/transmission, and their response or refractoriness to the activated immune system. We propose that multidimensional and multicentric approaches, based on diverse data integration coupled with comparative genomics and functional molecular infection epidemiology, would likely be successful in tracking the emergence and spread of MDR pathogens and thereby guiding the global infection control strategies in a highly informed manner.