Biomarkers for Helicobacter pylori infection and gastroduodenal diseases

Analysis of Gastric Diseases and Their Symptoms Based on Indexes of Pepsinogen I (PGI) and Pepsinogen II (PGII): Take 1106 Patients as Samples

In this study, preoperative analysis of 1106 gastropathy patients with abdominal pain, vomiting, dyspepsia, and other symptoms was conducted. Independent sample $t$ -test and correlation analysis and other ways were used for data cleansing and analysis. Findings were as follows: (1) Samples of different genders showed significance in PGI and PGII. The PGI and PGII values of women were significantly lower than those of men. (2) Age showed a significant positive correlation with PGI and PGII, which indicates that as the age increases, the PGI and PGII values become higher. (3) There was a significant negative correlation between age and abdominal pain. This signified that the younger the patient is, the more likely they will suffer abdominal pain. (4) PGI displayed a positive correlation with abdominal pain in the digestive tract (dyspepsia, gastrointestinal ulcers, gastrointestinal bleeding, etc.). It indicated that the higher the PGI value is, the more likely the patients will suffer abdominal pain and gastrointestinal diseases (dyspepsia, gastrointestinal ulcer, gastrointestinal hemorrhage, etc.). (5) PGII displayed a significant positive correlation with gastrointestinal diseases (dyspepsia, gastrointestinal ulcer, gastrointestinal hemorrhage, etc.) and a negative correlation with gastropathy (acute gastritis, chronic superficial gastritis, gastric ulcer, etc.). It indicated that the higher the value of PGII is, the more likely the patients will suffer symptoms of gastrointestinal diseases (dyspepsia, gastrointestinal ulcer, gastrointestinal hemorrhage, etc.), while less likely the patients will suffer gastropathy (acute gastritis, chronic superficial gastritis, gastric ulcer, etc.).

Matrix Metalloproteinases in Helicobacter pylori-Associated Gastritis and Gastric Cancer

Gastric cancer is one of the leading causes of the cancer-related mortality worldwide. The etiology of this disease is complex and involves genetic predisposition and environmental factors, including Helicobacter pylori. Infection of the stomach with H. pylori leads to gastritis and gastric atrophy, which can progress stepwise to gastric cancer. Matrix metalloproteinases (MMPs) actively participate in the pathology development. The further progression of gastric cancer seems to be less dependent on bacteria but of intra-tumor cell dynamics. Bioinformatics data confirmed an important role of the extracellular matrix constituents and specific MMPs in stomach carcinoma invasion and metastasis, and revised their potential as predictors of the disease outcome. In this review, we describe, in detail, the impact of MMPs in H. pylori-associated gastritis and gastric cancer.

Advances in diagnosis of Helicobacter pylori through biosensors: Point of care devices

Invasive as well as non-invasive conventional techniques for the detection of Helicobacter pylori (H. pylori) have several limitations that are being overcome by the development of novel, rapid and reliable biosensors. Herein, we describe several biosensors fabricated for the detection of H. pylori. This review aims to provide the principles of biosensors and their components including in the context to H. pylori detection. The major biorecognition elements in H. pylori detection include antigen/antibodies, oligonucleotides and enzymes. Furthermore, the review describes the transducers, such as electrochemical, optical and piezoelectric, also including microfluidics approaches. An overview of the biomarkers associated with H. pylori pathogenesis is also discussed. Finally, the prospects of advancement and commercialization of point-of-care tools are summarized.

Pepsinogen and Serum IgG Detection Is a Valuable Diagnostic Method for Helicobacter pylori Infection in a Low-Prevalence Country: A Report from Sri Lanka

The use of serum anti-Helicobacter pylori IgG and pepsinogen (PG) detection as a diagnostic method was evaluated in Sri Lanka. Gastric biopsies were performed (353 patients), and the prevalence of H. pylori infection was 1.7% (culture) and 2.0% (histology). IgG serology testing showed an area under the curve (AUC) of 0.922 (cut-off, 2.95 U/mL; specificity, 91.56%; sensitivity, 88.89%). Histological evaluation showed mild atrophy (34.3%), moderate atrophy (1.7%), metaplasia (1.7%), chronic gastritis (6.2%), and normal tissue (56%). The PGI/PGII ratio was significantly higher in H. pylori-negative patients (p < 0.01). PGII and PGI/PGII levels were lower in patients with metaplasia than in those with normal mucosa (p = 0.049 and p < 0.001, respectively). The PGI/PGII ratio best discriminated metaplasia and moderate atrophy (AUC 0.88 and 0.76, respectively). PGI and PGII alone showed poor discriminative ability, especially in mild atrophy (0.55 and 0.53, respectively) and chronic gastritis (0.55 and 0.53, respectively). The best cut-off to discriminate metaplasia was 3.25 U/mL (95.19% specificity, 83.33% sensitivity). Anti-H. pylori IgG and PG assessment (ABC method) was performed (group B, 2.0%; group A, 92.1%). The new cut-off more accurately identified patients with metaplasia requiring follow-up (group B, 5.4%). Assessment of anti-H. pylori IgG and PG is valuable in countries with a low prevalence of H. pylori infection.

Association between serum pepsinogen and atherosclerotic cardiovascular disease

BACKGROUND AND AIM

Serum pepsinogens (PGs) are biomarkers for gastric mucosal damage and have been reported to be associated with atherosclerosis. Its correlation with atherosclerotic cardiovascular disease (ASCVD) is still unknown. This study aimed to explore the association between serum PGs and ASCVD for providing physicians with an integrative picture to make rational plans in the diagnosis and treatment of ASCVD.

METHODS AND RESULTS

The concentrations of serum PGs and their distributions between ASCVD and non-ASCVD were compared by non-parametric test, Chi-squared test and Fisher exact test. The correlation between variables was analyzed by Spearman's correlation test. The association of serum PGs with ASCVD was analyzed by the binary logistic regression and two-piecewise linear regression. A total of 8355 recruited cases were eligible for the study. The concentrations of serum PGs were significantly different between the ASCVD and non-ASCVD groups (P = 0.025, P < 0.001). The lower PGI and PGR levels were significantly correlated with a high risk of ASCVD presence after adjustment for 26 potential covariates. Moreover, there was a linear relationship between the high level of PGII and the high risk of ASCVD [adjusted OR = 1.16 (1.00, 1.37), P = 0.07]. A nonlinear relationship of PGI/PGR and ASCVD (P = 0.08/<0.001) was also revealed. The risk of ASCVD increased with a range of log PGI ≥2.13 (PGI≥131 ng/mL) [adjusted OR = 4.67 (1.00, 23.17)], and decreased with a range of log PGR ≥0.22 (1.65) [adjusted OR = 0.59 (0.48, 0.74), P < 0.001].

CONCLUSIONS

Serum PGI and PGR are nonlinearly correlated with ASCVD, while PGII is linearly correlated with ASCVD. Among all PGs, PGR may serve as a reliable biomarker for ASCVD.

Gastric Damage and Cancer-Associated Biomarkers in Helicobacter pylori-Infected Children

Helicobacter pylori (H. pylori) is well-known to be involved in gastric carcinogenesis, associated with deregulation of cell proliferation and epigenetic changes in cancer-related genes. H. pylori infection is largely acquired during childhood, persisting long-term in about half of infected individuals, a subset of whom will go on to develop peptic ulcer disease and eventually gastric cancer, however, the sequence of events leading to disease is not completely understood. Knowledge on carcinogenesis and gastric damage-related biomarkers is abundant in adult populations, but scarce in children. We performed an extensive literature review focusing on gastric cancer related biomarkers identified in adult populations, which have been detected in children infected with H. pylori. Biomarkers were related to expression levels (RNA or protein) and/or methylation levels (DNA) in gastric tissue or blood of infected children as compared to non-infected controls. In this review, we identified 37 biomarkers of which 24 are over expressed, three are under expressed, and ten genes are significantly hypermethylated in H. pylori-infected children compared to healthy controls in at least 1 study. Only four of these biomarkers (pepsinogen I, pepsinogen II, gastrin, and SLC5A8) have been studied in asymptomatically infected children. Importantly, 13 of these biomarkers (β-catenin, C-MYC, GATA-4, DAPK1, CXCL13, DC-SIGN, TIMP3, EGFR, GRIN2B, PIM2, SLC5A8, CDH1, and VCAM-1.) are consistently deregulated in infected children and in adults with gastric cancer. Future studies should be designed to determine the clinical significance of these changes in infection-associated biomarkers in children and their persistence over time. The effect of eradication therapy over these biomarkers in children if proven significant, could lead to modifications in treatment guidelines for younger populations, and eventually promote the development of preventive strategies, such as vaccination, in the near future.

Analysis of the gut microbiota in alopecia areata: identification of bacterial biomarkers

BACKGROUND

Alopecia areata is a T-cell-mediated autoimmune disease with an unknown etiopathogenesis. Gut microbiota has been revealed as a key modulator of systemic immunity.

OBJECTIVE

To determine whether patients affected by alopecia universalis present differences in gut bacteria composition compared with healthy controls and investigate possible bacterial biomarkers of the disease.

METHODS

We conducted a cross-sectional study that involved 15 patients affected by alopecia universalis and 15 controls. Gut microbiome of the study subjects was analysed by sequencing the 16SrRNA of stool samples. We searched for bacterial biomarkers of alopecia universalis using the linear discriminant analysis effect size (LEFse) tool.

RESULTS

In total, 30 study subjects (46.6% female; mean [SD] age, 40.1 [9.8] years) were enrolled. Neither alpha (Shannon diversity index 5.31 ± 0.43 vs. 5.03 ± 0.43, P 0.1) or beta diversity (ADONIS P value: 0.35) of gut microbiota showed statistically significant differences between cases and controls. In patients affected with alopecia, we found an enriched presence (LDA SCORE > 2) of Holdemania filiformis, Erysipelotrichacea, Lachnospiraceae, Parabacteroides johnsonii, Clostridiales vadin BB60 group, Bacteroides eggerthii and Parabacteroides distasonis. A predictive model based on the number of bacterial counts of Parabacteroides distasonis and Clostridiales vadin BB60 group correctly predicted disease status in 80% of patients (AUC 0.804 (0.633-0.976), P 0.004).

CONCLUSION

Alopecia universalis does not seem to affect broadly gut microbiota structure. Bacterial biomarkers found associated with the disease (Holdemania filiformis, Erysipelotrichacea, Lachnospiraceae, Parabacteroides johnsonii, Eggerthellaceae, Clostridiales vadin BB60 group, Bacteroides eggerthii and Parabacteroides distasonis) should be further studied as they could be involved in its pathophysiology or be used as diagnostic tools.

Carrying a 112 bp-segment in Helicobacter pylori dupA may associate with increased risk of duodenal ulcer

The discovery of Helicobacter pylori in 1983 challenged researchers around the world to identify this pathogen's major virulence factors. The main rationale for this kind of research was to identify a biomarker associated with specific diseases following H. pylori colonization. Among different investigated virulence factors, duodenal ulcer promoting gene A (dupA) has been found to be associated with duodenal ulcer (DU), but its effect was different in various geographical regions. To determine the prevalence of dupA, we applied both classic primer pairs and our newly developed primers producing a highly conserved segment in PCR method. In our survey, 143 (47%) H. pylori isolates were obtained from 304H. pylori-colonized individuals [age range of 19-92; 113 (37%) males with the mean age of 50 and 191 (63%) females with the mean age of 49]. The presence of the dupA gene was investigated by using the different specific primers. The prevalence of the 112 bp segment isolated from H. pylori strains recovered from DU, GU and atrophy groups were significantly higher (81%, p value = .002, 64%, p = .065, 68% and p = .047 38%, respectively) than our control group, where the prevalence of the 112 bp segment was only 38%. Interestingly, a significant relationship was observed between the occurrence of DU and the presence of the 112 bp segment [p = .002; OR: 6.98; (95% CI: 1.94-25.00)]. Taken as a whole, we believe the 112 bp region of H. pylori dupA may serve as the first detected biomarker for the early detection of DU in patients admitted to hospitals.

Searching for serum protein markers of equine squamous gastric disease using gel electrophoresis and mass spectrometry

BACKGROUND

Equine squamous gastric disease (ESGD) is a very common disorder but an accurate and practical screening technique for detecting ESGD is currently lacking.

OBJECTIVES

To identify serum protein markers to detect ESGD using electrophoresis and mass spectrometry.

STUDY DESIGN

Proteomic analysis and bioinformatics.

METHODS

ESGD was diagnosed using gastroscopy in 30 horses. Gastric ulceration was categorised into three groups: normal, mild/moderate and severe ESGD. Pooled sera from each group were compared using 1D electrophoresis and mass spectrometry. The candidate proteins for ESGD markers were selected based on their specifically high expression in nonglandular stomach, and their association with gastric ulceration using public gene and protein databases.

RESULTS

The prevalence of ESGD in this study was 43% (with mild/moderate ESGD at 33% and severe ESGD at 10%). The proteomic study revealed that the identified serum protein markers for normal equine stomach were B4GALNT2 and XDH. The marker for mild/moderate EGSD was KRT10, while the marker for severe ESGD was KLK13. Furthermore, markers for both ulcer types were SLC4A7, PPARG, FCGBP, PKP1, ASPRV1 and KRT5-like proteins.

MAIN LIMITATIONS

The functions of the identified proteins are not well characterised in horse. Proteomics is a tool for screening protein markers, but confirmation of putative protein markers with specific antibodies is required.

CONCLUSIONS

In total, 10 serum proteins found in this study may be used as putative markers for ESGD. However, confirmation of candidate proteins with specific antibodies in a larger study cohort is necessary before it can be used in the veterinary clinic or on horse farms. The Summary is available in Portuguese - see Supporting Information.

Circulating microRNA signatures serve as potential diagnostic biomarkers for Helicobacter pylori infection

Helicobacter pylor (H pylori), a Gram-negative, microaerobic human pathogen, has been found to be involved in many gastroduodenal diseases. Accurate diagnosis of H pylori infection is a vital part of the effective management of gastroduodenal diseases. Circulating microRNAs (miRNAs) have shown the potential to be used as noninvasive biomarkers for the diagnosis of infectious diseases. The aim of this study was to explore plasma miRNAs as noninvasive biomarkers for H pylori infection. We performed a plasma miRNA expression profile using Illumina high-throughput sequencing and validated the levels of differentially expressed miRNAs in the plasma of 63 H pylori-infected patients and 41 healthy volunteers by quantitative real-time polymerase chain reaction (qRT-PCR). The sequencing results showed that 37 miRNAs were upregulated in the H pylori-infected patients compared with that in the healthy volunteers, while six miRNAs were downregulated. qRT-PCR and receiver operator characteristic analysis suggested that the expression of miR-28-3p, miR-143-3p, miR-151a-3p, and miR-148a-3p were closely associated with H pylori infection. Therefore, the four plasma miRNA panels mentioned above could serve as promising noninvasive biomarkers of H pylori infection.

MicroRNA-Regulated Rickettsial Invasion into Host Endothelium via Fibroblast Growth Factor 2 and Its Receptor FGFR1

Microvascular endothelial cells (ECs) represent the primary target cells during human rickettsioses and respond to infection via the activation of immediate–early signaling cascades and the resultant induction of gene expression. As small noncoding RNAs dispersed throughout the genome, microRNAs (miRNAs) regulate gene expression post-transcriptionally to govern a wide range of biological processes. Based on our recent findings demonstrating the involvement of fibroblast growth factor receptor 1 (FGFR1) in facilitating rickettsial invasion into host cells and published reports suggesting miR-424 and miR-503 as regulators of FGF2/FGFR1, we measured the expression of miR-424 and miR-503 during R. conorii infection of human dermal microvascular endothelial cells (HMECs). Our results revealed a significant decrease in miR-424 and miR-503 expression in apparent correlation with increased expression of FGF2 and FGFR1. Considering the established phenomenon of endothelial heterogeneity and pulmonary and cerebral edema as the prominent pathogenic features of rickettsial infections, and significant pathogen burden in the lungs and brain in established mouse models of disease, we next quantified miR-424 and miR-503 expression in pulmonary and cerebral microvascular ECs. Again, R. conorii infection dramatically downregulated both miRNAs in these tissue-specific ECs as early as 30 min post-infection in correlation with higher FGF2/FGFR1 expression. Changes in the expression of both miRNAs and FGF2/FGFR1 were next confirmed in a mouse model of R. conorii infection. Furthermore, miR-424 overexpression via transfection of a mimic into host ECs reduced the expression of FGF2/FGFR1 and gave a corresponding decrease in R. conorii invasion, while an inhibitor of miR-424 had the expected opposite effect. Together, these findings implicate the rickettsial manipulation of host gene expression via regulatory miRNAs to ensure efficient cellular entry as the critical requirement to establish intracellular infection.

Optimisation of a serum albumin removal protocol for use in a proteomic study to identify the protein biomarkers for silent gastric ulceration in horses

Silent gastric ulceration occurs without evidence of clinical signs and is common in horses. There is currently no a simple and effective method to diagnose this disease. Proteomics can be used to identify serum biomarkers, but the most abundant serum protein, albumin, could conceal candidate biomarkers. Therefore, it is recommended to remove albumin before a proteomic study; however, there is no specific albumin depletion kit or standard protocol available for horse samples. The objectives of this study were to optimise a protocol to remove equine serum albumin and to use albumin-depleted serum to identify the protein biomarkers for silent gastric ulceration. Gastroscopy was used to identify gastric ulceration, and serum was obtained from horses with either a healthy gastric mucosa or gastric ulceration. Serum albumin was removed using the trichloroacetic acid (TCA) protein precipitation method, and this protocol was optimised by varying the concentration of TCA, type of organic solvents, ratio of serum to protein precipitation solution, and incubation times. Electrophoresis and image analysis were used to compare the amounts of albumin, immunoglobulins G (IgG), and protein degradation before and after TCA precipitation. The best protocol was chosen to remove albumin for a proteomic study (electrophoresis and mass spectrometry). The results revealed that protocol 2 (ratio of serum to solution 1:5, 10% TCA in acetone, and 90 min incubation) was the most efficient protocol to remove albumin (98%) and IgG heavy (80%) and light (98%) chains without degrading other proteins. After electrophoresis and mass spectrometry analysis, KRT1, KRT6A and KRT18 were identified as potential markers for silent gastric ulceration.

Pepsinogen C expression, regulation and its relationship with cancer

Pepsinogen C (PGC) belongs to the aspartic protease family and is secreted by gastric chief cells. PGC could be activated to pepsin C and digests polypeptides and amino acids, but as a zymogen PGC’s functions is unclear. In normal physiological conditions, PGC is initially detected in the late embryonic stage and is mainly expressed in gastric mucosa. The in situ expression of PGC in gastric mucosa is decreased considerably in the process of superficial gastritis → atrophic gastritis → gastric cancer (GC), proving that PGC is a comparatively ideal negative marker of GC. Serum PGC, and PGA levels and the PGA/PGC ratio have satisfactory sensitivity, specificity and price–quality ratio for predicting high GC risk. Ectopic PGC expression is significantly increased in prostate cancer, breast cancer, ovary cancer and endometrial cancer. In those sex-related cancers high level PGC expression indicates better prognosis and longer survival. The regulation of PGC expression involves genetic and epigenetic alteration of the encoding PGC gene, hormones modulation and interactions between PGC with other transcription factors and protein kinases. More and more research evidence hinted that PGC has strong correlation with cancer. In the systematic review, we respectively elaborate the structure, potential physiological functions, expression characteristics and regulation of PGC, and especially focus on the relationship between PGC expression and cancer to highlight the role of PGC in the tumorigenesis and its application value in clinical practice.

Association Between IL-4 and IL-6 Expression Variants and Gastric Cancer Among Portuguese Population

Introduction

Multiple studies have reported strong associations between Helicobacter pylori (Hp) inflammation and gastric cancer (GC) development. Altered expressions of pro/anti-inflammatory cytokines have a crucial role in Hp and GC proliferation. Although there are many studies related to cytokines polymorphisms involvement in GC risk, the role of Interleukin-4 (IL-4) and Interleukin-6 (IL-6) in gastric inflammation process is not yet clarified.

Aim

This study aimed to investigate the impact of common IL-4 and IL-6 polymorphisms in GC development risk among Portuguese population.

Methods

A total of 100 GC biopsies (50 with intestinal type, IGC, 50 with diffuse type, DGC) and 50 chronic gastritis cases, used as control group, were included in this case-control study. IL-4 and IL-6 common polymorphisms were genotyped by PCR-SSP, using commercially available kits.

Results

IL-4 low producer genotypes, IL-4-590TT (OR = 6.7; 95% CI 1.4–32.4) and IL-4-1098GG (OR = 4.4; 95% CI 1.7–16.9) were found associated with IGC and DGC, respectively. We also verified that IL-4 TTT haplotype was linked with both IGC (OR = 5.8; 95% CI 2.3–14.4) and DGC (OR = 2.3; 95% CI 1.0–5.5) groups. Concerning IL-6 results, IL-6-174CG genotype showed a higher prevalence among IGC cases (OR = 7.3; 95% CI 2.7–20.3), and IL-6-174CC (OR = 3.8; 95% CI 1.7–8.7) showed upper prevalence within DGC subjects. Finally, IL-6-174/nt565CG haplotype showed a significant association with both IGC (OR = 7.3; 95% CI 2.7–20.3) and DGC (OR = 7.9; 95% CI 4.2–14.9).

Conclusion

IL-6 and IL-4 expression variants seem to have an important role in GC risk mechanisms. This study provides preliminary evidence that IL-4 and IL-6 polymorphisms, although not directly linked to the disease, may be useful tools in the study of this multifactorial disease.