ABH and Lewis blood group systems and their relation to diagnosis and risk of Helicobacter pylori infection

The immune microenvironment in gastric adenocarcinoma

Like most solid tumours, the microenvironment of epithelial-derived gastric adenocarcinoma (GAC) consists of a variety of stromal cell types, including fibroblasts, and neuronal, endothelial and immune cells. In this article, we review the role of the immune microenvironment in the progression of chronic inflammation to GAC, primarily the immune microenvironment driven by the gram-negative bacterial species Helicobacter pylori. The infection-driven nature of most GACs has renewed awareness of the immune microenvironment and its effect on tumour development and progression. About 75-90% of GACs are associated with prior H. pylori infection and 5-10% with Epstein-Barr virus infection. Although 50% of the world's population is infected with H. pylori, only 1-3% will progress to GAC, with progression the result of a combination of the H. pylori strain, host susceptibility and composition of the chronic inflammatory response. Other environmental risk factors include exposure to a high-salt diet and nitrates. Genetically, chromosome instability occurs in ~50% of GACs and 21% of GACs are microsatellite instability-high tumours. Here, we review the timeline and pathogenesis of the events triggered by H. pylori that can create an immunosuppressive microenvironment by modulating the host's innate and adaptive immune responses, and subsequently favour GAC development.

Development of an easy-to-use urease kit for detecting Helicobacter pylori in canine gastric mucosa

BACKGROUND AND AIM

Helicobacter pylori is an important pathogen in humans and animals involved in chronic gastritis, leading to the development of gastric cancer. Urease produced by H. pylori is an enzyme that promotes bacterial colonization and can be used clinically as a biomarker of H. pylori infection as part of a rapid urease test (RUT). A test with high specificity (95-100%) would be more convenient and faster than histopathology, bacterial culture, and polymerase chain reaction (PCR). The aim of this study was to develop a simple, cheap, and fast kit for detecting H. pylori infection in the gastric mucosa of canines, which can be used in clinical practice for diagnosing infection with this bacterium.

MATERIALS AND METHODS

The RUT assays developed were prepared using 1% agar, 1% sodium phosphate monobasic, and 1% urea followed by the addition of 3% methyl red indicator. The cutoff value of sensitivity of the RUT assay was established using the urease of H. pylori ATCC 43504 and color change was monitored for 24 h. Comparisons of the sensitivity to H. pylori ATCC 43504 were made between the developed RUT assays and the Hp Fast™ commercial kit. Then, the limit of detection for H. pylori ATCC 43504 number was analyzed by the SYBR Green real-time PCR assay to measure the copy number of the ureC gene. Gastric biopsy samples from the antrum, body, and fundus of the stomach were collected from eight canines presenting with vomiting and gastroenteritis. Analyses were performed on fresh samples using the developed RUT assays and the Hp Fast™ commercial kit, which were read within 24 h; then, the results were confirmed with SYBR Green real-time PCR. The specificity of the RUT assays was tested with a number of different bacteria, including Staphylococcus pseudintermedius, Proteus spp., Pseudomonas aeruginosa, Klebsiella pneumoniae, Enterococcus spp., Escherichia coli, and Salmonella spp.; H. pylori ATCC 43504 was used as a positive control.

RESULTS

The results showed that the developed assays were sensitive to the urease enzyme at 0.1 mg/mL. The lowest detection limit of this assay for H. pylori ATCC 43504 was found to be 102 copies at 30 min. The sensitivity of detection of H. pylori in gastric biopsies of canines occurred in a minimum of 30 min. The RUT showed similar results to the Hp Fast™ commercial kit. In the developed RUT, the color change of the test from red to yellow could be clearly distinguished between the color of the positive test and the negative one; however, in the commercial Hp Fast™, it was difficult to observe the gel color changein the negative pH range of 5.8 and the positive pH of 6.5. The developed RUT was specific for H. pylori and did not detect any of the other tested bacteria. The test kit can also be stored for 6 months at 4°C.

CONCLUSION

The sensitivity of the developed assays allowed the detection of urease enzyme at a minimum concentration of 0.1 mg/mL. Our RUT could also detect H. pylori from one in eight canine specimens at a minimum of 102 copies within 30 min. This RUT is specific to H. pylori as it did not detect any of the other tested bacteria.