((Master thesis))
Abstract
Introduction:
Helicobacter pylori is one of the most important human stomach pathogens. BabA2, Hpa HsP genes are essential in binding to gastric epithelial cells and bacterial pathogenicity. The frequency of these genes is different in different geographical regions. The aim of this study was to evaluate the frequency of BabA2, Hsp Hpa genes in Helicobacter pylori isolates isolated from gastric biopsies and their relationship with gastritis, ulcer and gastric cancer.
Research method:
Stomach biopsy samples taken by a gastroenterologist from patients with digestive disorders
One sample was sent to the laboratory for urease test and histopathology examination and another sample was sent to the laboratory for DNA extraction. After DNA extraction, the frequency of Hpa, BabA2, and Hpa genes were checked using their specific primers and molecular PCR method. Findings: Among 80 patients infected with Helicobacter pylori, 36 patients had gastritis, 18 patients had gastric cancer, and 26 patients had stomach ulcers and 80 biopsy samples In the investigated stomach, 51 samples (63%) were positive for the gene. The frequency of BabA2 gene in Helicobacter pylori isolated from biopsies of patients in gastric cancer was (13.8%) and in gastritis (26.2%) and gastric ulcer (23.8%). Also, 49 samples (61%) were positive for Hsp gene. 49 samples (61%) were positive for Hsp gene. The frequency of Hsp gene in Helicobacter pylori isolated from biopsies of patients with gastric cancer (10%), gastritis (26.2%) and gastric ulcer (25%) was 49 samples (61%) were positive for Hsp gene. The frequency of Hsp gene in Helicobacter pylori isolated from the biopsies of patients with gastric cancer (10%), gastritis (26.2%), and gastric ulcer (25%) has been patients with gastric cancer (10%), gastritis (26.2%) and gastric ulcer (25%) also 57 samples (71.2%) were positive for Hpa gene. The frequency of Hpa gene in Helicobacter pylori isolated from biopsies of patients with gastric cancer (12%) and gastritis (31%) and gastric ulcer (27.5%) was high. No significant correlation was observed between the presence of these genes and the type of gastric pathology. (p>0.05)
Conclusion:
In this study The frequency of babA2, hpa and hsp genes was higher in gastric ulcer and gastritis samples. And there was no statistically significant relationship between the presence of genes and the type of pathology caused by Helicobacter pylori. The reason for the difference in the frequency of these genes in different studies can be due to the difference in geographical diversity or the use of different primers to track these genes.
Key words:
Helicobacter pylori, BabA2 gene, Hpa gene, Hsp gene, peptic ulcer, gastric cancer
Introduction:
Helicobacter pylori is a microaerophilic gram-negative bacillus. The main habitat of bacteria is the human gastric mucosa, which is replaced under the mucous layer. It is the most common bacterial infection in the world, epidemiological studies have shown that nearly half of the population and the majority of people in developing countries are infected with this bacterium. Humans are the primary natural reservoir of Helicobacter pylori infection, which is mainly transmitted through fecal-oral, oral-oral, or through the consumption of drinking water or contaminated vegetables.
Infection with this bacterium is very widespread among the human population, it is known that it plays an important role in the pathogenesis of the digestive tract, in diseases such as gastric ulcer, duodenal ulcer, lymphoma of the gastric mucosa in connection with lymphoid tissue, and cancer of the end of the stomach. slow, so that it causes 95% of chronic inflammation of the stomach, 70-80% of gastroduodenal diseases and causes stomach cancer. Chronic Helicobacter pylori infection may be associated with chronic gastritis, peptic ulcer diseases, gastric adenocarcinoma. (11, 14) Recent studies show that people infected with Helicobacter pylori are highly prone to tissue lymphoma.(11, 14) Recent studies show that people with Helicobacter pylori infection are highly prepared to develop MALTOMA, Mucosal Associated Lymphoid Tissue, and distal adenocarcinoma, and all patients with duodenal ulcers have gastritis caused by Helicobacter pylori, so that the wound heals after treating Helicobacter pylori infection. (12)
The results published by the World Health Organization consistently show that approximately 50% of adults in developed countries and approximately 90% of adults in developing countries are infected with Helicobacter pylori, and in most cases, these people do not show any clinical symptoms, therefore, a person infected with Helicobacter pylori may develop a disease
years after the beginning of the infection, and until then the microbe is settled in the stomach of the infected person without causing any symptoms. (13)
The presence of Helicobacter pylori in the stomach tissue stimulates the immune system and produces antibodies against the bacteria, which can be detected using serological tests and the PCR (Polymerase Chain Reaction) molecular method and represents the infection in the person.
Several virulence factors such as antigens related to secreted proteins are involved in the pathogenesis of Helicobacter pylori. These antigens include:
urease, hemagglutinin, LPs, CagA protein, vacuolating cytotoxin called Vac, as well as other pathogenic factors such as flagellum, outer membrane proteins, and heat shock proteins or HSP are also involved, which are among the antigenic factors. (17, 7)
The pathogenicity of OMP and HSP of Helicobacter pylori are able to penetrate the adhesive layers of the gastric mucosa and cause the destruction of gastric epithelial cells and gastric mucosal ulceration, and the result is modulation of the host's immune system. (14, 15) Outer membrane proteins (OMP) include: (Heat shock) 70 and HsP 60, (H. Pylori agglutinin) HPaA and A-E HoPs and HoPZ and AoB Alp and BabA and (Proteins) LPs and Nap (in)mu gastric for adhesion) LPs and antigen LPsO and Core
and proteins 63 and 61, 25, 6, 19 kilodaltons and cellular receptors of Lewin b, N acetylneurasinyl lactose (sialic acid), lactosyl ser acid sulfate, laminin, Lewis X, moisin, heparan sulfate and other sulfated polysaccharides, phosphatidylethanolamine, gangliotriacylceramide, beta integrin. Heat shock proteins play an important role in directing and delivering antigens through MHC class I and inducing cell responses. Today, this role of HSPs is used as a suitable marker for the preparation of anti-cancer vaccines.
HSP proteins play a role as molecular chaperones in the processes of accumulation and transfer of peptides and processing of antigens under physiological conditions. These Helicobacter pylori adhesins are used as a molecular marker in Hpylori diagnosis. (3 and 19)
A hpa, 2 babA, hsp70 genes encode proteins that facilitate bacterial virulence by increasing cytotoxin production and increasing host cell adhesion. The presence of these genes causes severe clinical consequences in gastroduodenal and dyspepsia patients. (3, 7, 10, 8)
History of the discovery of Helicobacter pylori:
For the first time in 1893, the existence of spiral organisms colonized in the gastric mucosa of healthy dogs was reported by Bizzozero in Italy, but the first human case was reported more than 20 years later, in 1906 by Krienits (97).