Reciprocal impact of host factors and Helicobacter pylori genotypes on gastric diseases

Helicobacter pylori Outer Membrane Proteins and Virulence Factors: Potential Targets for Novel Therapies and Vaccines

Helicobacter pylori is a gastric oncopathogen that infects over half of the world's human population. It is a Gram-negative, microaerophilic, helix-shaped bacterium that is equipped with flagella, which provide high motility. Colonization of the stomach is asymptomatic in up to 90% of people but is a recognized risk factor for developing various gastric disorders such as gastric ulcers, gastric cancer and gastritis. Invasion of the human stomach occurs via numerous virulence factors such as CagA and VacA. Similarly, outer membrane proteins (OMPs) play an important role in H. pylori pathogenicity as a means to adapt to the epithelial environment and thereby facilitate infection. While some OMPs are porins, others are adhesins. The epithelial cell receptors SabA, BabA, AlpA, OipA, HopQ and HopZ have been extensively researched to evaluate their epidemiology, structure, role and genes. Moreover, numerous studies have been performed to seek to understand the complex relationship between these factors and gastric diseases. Associations exist between different H. pylori virulence factors, the co-expression of which appears to boost the pathogenicity of the bacterium. Improved knowledge of OMPs is a major step towards combatting this global disease. Here, we provide a current overview of different H. pylori OMPs and discuss their pathogenicity, epidemiology and correlation with various gastric diseases.

Detection of Helicobacter pylori strain types and analysis of risk factors among subjects from Hainan Province, China

OBJECTIVE

To explore the prevalence of type I and type II Helicobacter pylori infection and investigate risk factors in a population from Hainan Province in China.

METHODS

Data came from a large, cross-sectional study conducted from August 2022 to April 2023 involving five cities of Hainan. Subjects with confirmed 14C-urea breath test (UBT) and positive serological assay were included. All subjects had a gastroscopy. According to presence or absence of CagA/VacA proteins, subjects were classified as either type I (present) or type II strains (absent). Gastroscopic findings and several socio-demographic factors were examined for correlation with antibody serotyping.

RESULTS

In total, 410 subjects were investigated for H. pylori strain types. The overall prevalence of the highly virulent, type I H. pylori strain was 79% (324/410) and type II strain was 21% (86/410). There was a strong association between type I strain and peptic ulcer disease. Of several sociodemographic factors investigated, only smoking and data over baseline (DOB) values showed significant differences between type 1 and type II strains. Logistic regression analysis showed a lower risk of type I H. pylori infection in smokers compared with non-smokers, and a higher risk of H. pylori type I infection in subjects with medium and high data over baseline (DOB) values compared with subjects who had low DOB values.

CONCLUSION

Highly virulent, type I H. pylori infections predominate in Hainan and the co-positivity of CagA and VacA antibodies are related to type I H. pylori infection. We found that Type I H. pylori was closely associated with peptic ulcer disease and the DOB values were generally high.

Use of immunoinformatics and the simulation approach to identify Helicobacter pylori epitopes to design a multi-epitope subunit vaccine for B- and T-cells

BACKGROUND

Helicobacter pylori cause a variety of gastric malignancies, gastric ulcers, and cause erosive diseases. The extreme nature of the bacterium and the implantation of this bacterium protects it against designing a potent drug against it. Therefore, employing a precise and effective design for a more safe and stable antigenic vaccine against this pathogen can effectively control its associated infections. This study, aimed at improving the design of multiple subunit vaccines against H. pylori, adopts multiple immunoinformatics approaches in combination with other computational approaches.

RESULTS

In this regard, 10 HTL, and 11 CTL epitopes were employed based on appropriate adopted MHC binding scores and c-terminal cut-off scores of 4 main selected proteins (APO, LeoA, IceA1, and IceA2). An adjuvant was added to the N end of the vaccine to achieve higher stability. For validation, immunogenicity and sensitization of physicochemical analyses were performed. The vaccine could be antigenic with significantly strong interactions with TOLK-2, 4, 5, and 9 receptors. The designed vaccine was subjected to Gromacs simulation and immune response prediction modelling that confirmed expression and immune-stimulating response efficiency. Besides, the designed vaccine showed better interactions with TLK-9.

CONCLUSIONS

Based on our analyses, although the suggested vaccine could induce a clear response against H. pylori, precise laboratory validation is required to confirm its immunogenicity and safety status.

Helicobacter pylori Related Diseases and Osteoporotic Fractures (Narrative Review)

Osteoporosis (OP) and osteoporotic fractures (OFs) are common multifactorial and heterogenic disorders of increasing incidence. Helicobacter pylori (H.p.) colonizes the stomach approximately in half of the world's population, causes gastroduodenal diseases and is prevalent in numerous extra-digestive diseases known to be associated with OP/OF. The studies regarding relationship between H.p. infection (HPI) and OP/OFs are inconsistent. The current review summarizes the relevant literature on the potential role of HPI in OP, falls and OFs and highlights the reasons for controversies in the publications. In the first section, after a brief overview of HPI biological features, we analyze the studies evaluating the association of HPI and bone status. The second part includes data on the prevalence of OP/OFs in HPI-induced gastroduodenal diseases (peptic ulcer, chronic/atrophic gastritis and cancer) and the effects of acid-suppressive drugs. In the next section, we discuss the possible contribution of HPI-associated extra-digestive diseases and medications to OP/OF, focusing on conditions affecting both bone homeostasis and predisposing to falls. In the last section, we describe clinical implications of accumulated data on HPI as a co-factor of OP/OF and present a feasible five-step algorithm for OP/OF risk assessment and management in regard to HPI, emphasizing the importance of an integrative (but differentiated) holistic approach. Increased awareness about the consequences of HPI linked to OP/OF can aid early detection and management. Further research on the HPI-OP/OF relationship is needed to close current knowledge gaps and improve clinical management of both OP/OF and HPI-related disorders.

The Role of Helicobacter pylori and Serum Pepsinogen Levels in Metachronous Gastric Cancer After Endoscopic Gastrectomy

PURPOSE

The current study aimed to explore the role of Helicobacter pylori (Hp) infection and serum pepsinogen (PG) levels in the occurrence of metachronous gastric cancer after endoscopic gastrectomy.

MATERIALS AND METHODS

Totally, 50 patients with metachronous gastric cancer, 50 patients with chronic atrophic gastritis and 50 healthy subjects were collected from October 2015 to October 2018. Patients in the gastric cancer group underwent endoscopic gastrectomy. Serum samples were collected for detection and correlation analysis of serum PG I, PG II, and Hp. In addition, the contents of serum PG and gastrin and postoperative adverse events were statistically analyzed.

RESULTS

There was a statistically significant difference in serum PG I levels, positive Hp infection rate, the number of mast cells, plasma motilin levels and postoperative adverse events among the 3 groups (P<0.01). There was also a significant difference in PG II levels among the groups (P<0.05). On the basis of the results, the amount of inflammatory cells in the gastric cancer group was significantly higher than that in the gastritis group, and there was a remarkable difference in gastric cancer patients before and after operation. Through data analysis, it was found that the levels of PG I and II were the highest in the healthy control group and the lowest in the gastric cancer group, the number of mast cells was the largest in the gastric cancer group, and the level of motilin was the highest in the healthy control group.

CONCLUSION

Hp infection and serum PG levels are associated with metachronous gastric cancer.

Effective antimicrobial activity of rifabutin against multidrug-resistant Helicobacter pylori

BACKGROUND

Helicobacter pylori resistance to more than one antibiotic is the main reason for failure in bacterial eradication in a considerable number of patients. Rifabutin (RFB) with a broad-spectrum of antimicrobial therapy has been suggested for treatment of refractory multidrug-resistant infections.

METHODS

Helicobacter pylori isolates from 104 patients were examined for resistance to 5 currently used antibiotics and RFB, using agar dilution method. Twofold serial dilutions of antibiotics were used and MICs (μg/mL) determined as metronidazole (MTZ 8), clarithromycin (CLR 2), amoxicillin (AMX 1), tetracycline (TET 0.5), furazolidone (FRZ 0.5), and RFB (0.06).

RESULTS

Of 104 H. pylori isolates, only 7 (6.7%) were sensitive to all the 6 antibiotics. However, 30 (28.8%) were resistant to one antibiotic, 28 (26.9%) to two, 19 (18.2%) to three, 14 (13.4%) to four, and 6 (5.7%) to five currently used antibiotics. Overall, 67(64.4%) of isolates were resistant to 2-5 currently used antibiotics and considered as multidrug-resistant (MDR), with 59 (88.1%) showing sensitivity to RFB and 8 (11.9%) resistance (P < 0.05). Of 33 isolates resistant to both MTZ and CLR, 25 (75.7%) were sensitive to RFB and 8 (24.3%) resistant (P < 0.05).

DISCUSSION

In vitro antimicrobial effectiveness of RFB on MDR H. pylori including those with resistance to both MTZ and CLR was demonstrated. However, RFB efficacy decreased as the number of antibiotics responsible for MDR increased. Considering that RFB inhibits both extra- and intracellular H. pylori, it can be suggested as an effective antibiotic against of MDR H. pylori.

Different serum motilin, gastrin, and pepsinogen levels in patients with different chronic gastric diseases associated with H. pylori infection

AIM

To investigate the differences in the number of mast cells (MCs) and plasma motilin (MTL), gastrin, and pepsinogen (PG) levels in the gastric mucosa of patients with Helicobacter pylori (H. pylori) infection related chronic gastric disease.

METHODS

From January 2015 to January 2017, 74 patients with H. pylori associated gastric ulcer (GU), 68 patients with H. pylori associated duodenal ulcer (DU), and 76 patients with chronic atrophic gastritis (CAG) treated at the Qixian Hospital of Keqiao District and Shaoxing Central Hospital were included in this study. Eighty healthy people who underwent medical examination in the same period at the Qixian Hospital of Keqiao District and Shaoxing Central Hospital were included as a control group (without H. pylori infection). The number of MCs and serum levels of motilin (MTL), gastrin, and PG were compared among the four groups.

RESULTS

The number of MCs was significantly higher and serum level of MTL was significantly lower in the CAG, GU, and DU groups than in the control group (P < 0.05). The DU group had the highest gastrin-17 level, followed by the GU, CAG, and control groups. PG I, PG II, and PG 1/2 ratio were significantly higher in the GU and DU groups than in the control group (199.74 mg/L ± 80.53 mg/L, 13.72 mg/L ± 5.75 mg/L vs 14.53 ± 5.42), while PG I and PG 1/2 ratio were significantly lower in the CAG group than in the control group (P < 0.05).

CONCLUSION

H. pylori infection may promote the development of GU, DU, and CAG by regulating serum levels of MTL, gastrin, and PG.