Gastric cancer and lymphoma

Occurrence of Helicobacter pylori in dental plaque and saliva of dyspeptic patients

BACKGROUND

Helicobacter pylori infection in the stomach is associated with gastric and duodenal ulcers, gastric cancers and gastric lymphoma. The organism is transmitted by ingestion, but the oral-oral route and the fecal-oral route are also suggested. The prevalence of infection with H. pylori in developing countries, including Brazil, is higher than in developed countries.

PURPOSE

This study aimed to evaluate the role of the oral cavity as a reservoir of this species, by evaluating the occurrence of H. pylori in supragingival dental plaque and in saliva of Brazilian dyspeptic patients, whether harboring the organism or not in the stomach.

MATERIAL AND METHODS

Forty-nine patients reporting dyspeptic symptoms were subjected to oral clinical examination and collection of saliva and supragingival dental plaque samples prior to the endoscopic examination. The detection of H. pylori in oral samples was performed by PCR using 16S rRNA primers. The bacteria were detected in stomach by means of the rapid urease test.

RESULTS

Helicobacter pylori was detected in the stomach of 20 of 49 subjects reporting dyspeptic symptoms. The organism was detected in only one supragingival plaque sample, obtained from a patient positive for the urease test in the stomach and in none of the salivary samples.

CONCLUSION

Supragingival dental plaque and saliva may not be relevant reservoirs of H. pylori.

A plasmid immunization construct encoding urease B of Helicobacter pylori induces an antigen-specific antibody response and upregulates the expression of beta-defensins and IL-10 in the stomachs of immunized mice

The objectives of this study were to investigate the efficacy of a prototype DNA immunization construct encoding the urease B subunit enzyme of Helicobacter pylori (H. pylori) for inducing adaptive and innate immune responses in mice immunized via intramuscular or subcutaneous routes and to further explore the adjuvant effects of the CpG motifs in the vector. Antibody, cytokine, and beta-defensin profiles were assessed in the stomachs of immunized animals: experiments were terminated 3 months after immunization because there was a significant increase in the anti-H. pylori urease B antibody response at Week 6 in mice immunized with the urease B construct. A long lasting expression of IL-10 mRNA was noted. Furthermore, a marked and sustained increase in the mRNA expression of beta-defensins was also observed, particularly beta1. This study demonstrates that an H. pylori urease B DNA construct can induce innate as well as adaptive immune responses in the stomachs of immunized mice. Upregulation of beta-defensin gene expression followed immunization and we believe that this is the first report of a DNA vaccine inducing innate anti-microbial responses. Such complex molecular interactions that modulate both innate and adaptive immune responses may be of critical importance in the control of mucosal pathogens, such as H. pylori.

Laboratory tests for the evaluation of Helicobacter pylori infections

Helicobacter pylori is a highly motile bacterium with multiple unipolar flagella, and it produces the urease enzyme. The flagella and urease are the virulence factors of H. pylori. H. pylori often establishes a chronic infection in the stomach that may lead to gastric and duodenal ulcers, gastric cancers, gastric lymphomas, and other gastrointestinal diseases. There are several different invasive and noninvasive clinical laboratory tests for H. pylori. Laboratory testing is not indicated in asymptomatic patients and should be considered only if treatment of H. pylori infection is planned. Invasive tests for H. pylori, such as tissue histology, culture, and rapid urease tests, are used if an endoscopy is performed on the patient. The noninvasive tests for H. pylori, such as enzyme antibody and urea breath tests, are recommended in patients whose symptoms do not warrant endoscopy. The urea breath test is very useful and is recommended to evaluate effectiveness in the eradication and treatment of H. pylori infections. Nucleic acid tests can complement other diagnostic procedures, and are useful in evaluating fixed biopsy tissue, environmental samples, gastric juices, oral secretions, and stool samples.