Helicobacter pylori infection has declined over recent decades. However, its prevalence remains high, and nearly 50% of the global population has been infected. In Korea, seroprevalence has steadily decreased in adults, but the status of H. pylori infection in children is unknown. The current status or trend of H. pylori infection in children is important because it can help estimate H. pylori-related diseases including gastric cancer in later life. In this review, the authors discuss the change in H. pylori infection rate among children and adolescents based on literature reviews and our research.

It has been demonstrated that vitamin C exhibits anti-cancer activity in various tumor cell lines; however, its specific mechanism of action remains unknown. Although the diagnosis and therapy of cancer patients have markedly improved in recent years, safer and more cost-effective treatments are still required. Therefore, the present study examined the effect of vitamin C on the induction of cell death in gastric cancer and its underlying mechanism of action. It was observed that the cytotoxicity of vitamin C on the human gastric cancer cell line AGS is dependent on the apoptotic pathway, including caspase cascades, but not on the necroptotic pathway. It was demonstrated that the vitamin C-induced calcium influx and ROS generation have critical roles in the induction of apoptosis. Furthermore, vitamin C treatment depleted adenosine triphosphate (ATP) production in AGS cells, and the autophagy pathway may be involved in this process. Taken together, the current study suggests that a high dose of vitamin C may induce gastric cancer cell apoptosis through the dysfunction of mitochondria, including calcium influx, reactive oxygen species generation and ATP depletion.

We tested correlations between anti-Helicobacter pylori IgG and IgA levels and the urease test, anti-CagA protein antibody, degree of gastritis, and age. In total, 509 children (0–15 years) were enrolled. Subjects were stratified as 0–4 years (n = 132), 5–9 years (n = 274), and 10–15 years (n = 103) and subjected to the urease test, histopathology, ELISA, and western blot using whole-cell lysates of H. pylori strain 51. The positivity rate in the urease test (P = 0.003), the degree of chronic gastritis (P = 0.021), and H. pylori infiltration (P < 0.001) increased with age. The median titer for anti-H. pylori IgG was 732.5 IU/mL at 0–4 years, 689.0 IU/mL at 5–9 years, and 966.0 IU/mL at 10–15 years (P < 0.001); the median titer for anti-H. pylori IgA was 61.0 IU/mL at 0–4 years, 63.5 IU/mL at 5–9 years, and 75.0 IU/mL at 10–15 years (P < 0.001). The CagA-positivity rate was 26.5% at 0–4 years, 36.5% at 5–9 years, and 46.6% at 10–15 years for IgG (P = 0.036), and 11.3% at 0–4 years, 18.6% at 5–9 years, and 23.3% at 10–15 years for IgA (P < 0.001). Anti-H. pylori IgG and IgA titers increased with the urease test grade, chronic gastritis degree, active gastritis, and H. pylori infiltration. Presence of CagA-positivity is well correlated with a high urease test grade and high anti-H. pylori IgG/IgA levels.

To identify the Helicobacter pylori antigens operating during early infection in sera from infected infants using proteomics and immunoblot analysis. Two-dimensional (2D) large and small gel electrophoresis was performed using H. pylori strain 51. We performed 2D immunoglobulin G (IgG), immunoglobulin A (IgA), and immunoglobulin M (IgM) antibody immunoblotting using small gels on sera collected at the Gyeongsang National University Hospital from 4–11-month-old infants confirmed with H. pylori infection by pre-embedding immunoelectron microscopy. Immunoblot spots appearing to represent early infection markers in infant sera were compared to those of the large 2D gel for H. pylori strain 51. Corresponding spots were analyzed by matrix-assisted laser desorption/ionization time of flight-mass spectrometry (MALDI-TOF-MS). The peptide fingerprints obtained were searched in the National Center for Biotechnology Information (NCBI) database. Eight infant patients were confirmed with H. pylori infection based on urease tests, histopathologic examinations, and pre-embedding immunoelectron microscopy. One infant showed a 2D IgM immunoblot pattern that seemed to represent early infection. Immunoblot spots were compared with those from whole-cell extracts of H. pylori strain 51 and 18 spots were excised, digested in gel, and analyzed by MALDI-TOF-MS. Of the 10 peptide fingerprints obtained, the H. pylori proteins flagellin A (FlaA), urease β subunit (UreB), pyruvate ferredoxin oxidoreductase (POR), and translation elongation factor Ts (EF-Ts) were identified and appeared to be active during the early infection periods. These results might aid identification of serological markers for the serodiagnosis of early H. pylori infection in infants.

PurposeTo assess gastric pH and its relationship with urease-test positivity and histological findings in children with Helicobacter pylori infection.MethodsFasting gastric juices and endoscopic antral biopsy specimens were collected from 562 children and subjected to the urease test and histopathological examination. The subjects were divided into 3 age groups: 0-4, 5-9, and 10-15 years. The histopathological grade was assessed using the Updated Sydney System, while the gastric juice pH was determined using a pH meter.ResultsThe median gastric juice pH did not differ significantly among the age groups (p=0.655). The proportion of individuals with gastric pH >4.0 was 1.3% in the 0-4 years group, 6.1% in the 5-9 years group, and 8.2% in 10-15 years (p=0.101). The proportions of moderate and severe chronic gastritis, active gastritis, and H. pylori infiltration increased with age (p<0.005). Urease-test positivity was higher in children with hypochlorhydria (77.8%) than in those with normal gastric pH (31.7%) (p<0.001). Chronic and active gastritis were more severe in the former than the latter (p<0.001), but the degree of H. pylori infiltration did not differ (20.9% vs. 38.9%; p=0.186).ConclusionGastric pH while fasting is normal in most children regardless of age. Urease-test positivity may be related to hypochlorhydria in children, and hypochlorhydria is in turn related to H. pylori infection.