Extragastric manifestations of Helicobacter pylori infection: Possible role of bacterium in liver and pancreas diseases.

Helicobacter pylori (H. pylori) is an ancient microorganism that has co-evolved with humans for over 60000 years. This bacterium typically colonizes the human stomach and it is currently recognized as the most common infectious pathogen of the gastroduodenal tract. Although its chronic infection is associated with gastritis, peptic ulcer, dysplasia, neoplasia, MALT lymphoma and gastric adenocarcinoma, it has been suggested the possible association of H. pylori infection with several extragastric effects including hepatobiliary and pancreatic diseases. Since a microorganism resembling H. pylori was detected in samples from patients with hepatobiliary disorders, several reports have been discussed the possible role of bacteria in hepatic diseases as hepatocellular carcinoma, cirrhosis and hepatic encephalopathy, nonalcoholic fatty liver disease and fibrosis. Additionally, studies have reported the possible association between H. pylori infection and pancreatic diseases, especially because it has been suggested that this infection could change the pancreatic physiology. Some of them have related a possible association between the microorganism and pancreatic cancer. H. pylori infection has also been suggested to play a role in the acute and chronic pancreatitis pathogenesis, autoimmune pancreatitis, diabetes mellitus and metabolic syndrome. Considering that association of H. pylori to liver and pancreas diseases needs further clarification, our work offers a review about the results of some investigations related to the potential pathogenicity of H. pylori in these extragastric diseases.

Virulence Factors of Helicobacter pylori: A Review.

Helicobacter pylori is a spiral-shaped Gram-negative bacterium that colonizes the human stomach and can establish a long-term infection of the gastric mucosa, a condition that affects the relative risk of developing various clinical disorders of the upper gastrointestinal tract, such as chronic gastritis, peptic ulcer disease, mucosa-associated lymphoid tissue (MALT) lymphoma, and gastric adenocarcinoma. H. pylori presents a high-level of genetic diversity, which can be an important factor in its adaptation to the host stomach and also for the clinical outcome of infection. There are important H. pylori virulence factors that, along with host characteristics and the external environment, have been associated with the different occurrences of diseases. This review is aimed to analyzing and summarizing the main of them and possible associations with the clinical outcome.

Evaluation of five DNA extraction methods for detection of H. pylori in formalin-fixed paraffin-embedded (FFPE) liver tissue from patients with hepatocellular carcinoma.

Since Helicobacter spp. DNA was identified in liver tissue resected from patients with hepatocelullar carcinoma (HCC), researchers have suggested a role of this bacterium in hepatic carcinogenesis. Archives of formalin-fixed, paraffin-embedded (FFPE) tissues represent an extraordinary source for clinical studies providing many advantages. However, DNA extraction from FFPE tissues is laborious, time-consuming and still remains a challenge. The aim of this study was to evaluate five protocols for DNA extraction from FFPE liver obtained from patients with HCC in order to detect Helicobacter pylori DNA. These methods were: (1) QIAamp FFPE Tissue Kit, (2) QIAamp DNA Mini Kit, (3) Wizard SV Genomic DNA Purification System, (4) RealiaPrep FFPE gDNA Miniprep System and (5) phenol-chloroform. H. pylori detection was performed using 16S rRNA gene amplification by PCR. The highest total amount of DNA was obtained using the phenol-chloroform method. Analyses of 16S rRNA gene amplification did not show statistically significant differences among the methods (p=0.466), although the highest percentage of positive cases (70%) was found in samples extracted with phenol-chloroform. We suggest that of the five methods evaluated, phenol/chloroform is the most suitable for detection of H. pylori in FFPE liver from patients with HCC.

Eradication Treatment of Helicobacter pylori Infection: Its Importance and Possible Relationship in Preventing the Development of Gastric Cancer.

Helicobacter pylori is the most important carcinogen for gastric adenocarcinoma. Bacterial virulence factors are essential players in modulating the immune response involved in the initiation of carcinogenesis in the stomach; host genetic factors contribute to the regulation of the inflammatory response and to the aggravation of mucosal damage. In terms of environmental factors, salt intake and smoking contribute to the development of lesions. Various therapeutic schemes are proposed to eradicate H. pylori infection, which could potentially prevent gastric cancer, offering the greatest benefit if performed before premalignant changes of the gastric mucosa have occurred.

Restriction fragment length polymorphism of urease C and urease B genes of Helicobacter pylori strains isolated from Brazilian patients with peptic ulcer and chronic gastritis.

The aim of the present work is to identify the presence of Helicobacter pylori bacterium in samples of gastric mucosa fragments, obtained by gastric biopsy, from Brazilian patients with peptic ulcer and chronic gastritis and also to determine differences among the prevalent strains in these two diseases by urease C and urease B genes amplification utilizing nested polymerase chain reaction (PCR) and PCR. We encountered 17 genotyping patterns for urease C and 7 for urease B and, although no significant differences were found among the patterns encountered for both diseases, we found predominant groups for each disease. Typing methods of the products obtained by nested PCR and PCR show a functional scheme and are of great importance for epidemiologic studies and H. pylori strain characterization, in addition to allowing correlation among the several strains and their role in the diseases caused by this microorganism.