H. Pylori and its link to Gastric Cancer Discovery
In 2005, Australian scientists Dr. Barry Marshall and Dr. Robin Warren were awarded the Nobel Prize in Medicine for their groundbreaking discovery of Helicobacter pylori (H. pylori) bacterium and its role in causing chronic gastritis and gastric ulcers. Their discovery also underscored the potential link between chronic H. pylori infection and the increased risk of developing gastric cancer, highlighting the importance of addressing this infection to prevent more severe gastrointestinal diseases. This was a pivotal moment in medical science, demonstrating that H. pylori infection is the main cause of these conditions, fundamentally shifting how these diseases are treated.
What is H. Pylori?
Pylori is a gram-negative bacterium which causes chronic gastritis and plays important roles in peptic ulcer disease, gastric carcinoma, and gastric lymphoma. H. pylori has been found in the stomachs of humans in all parts of the world. In developing countries, 70 to 90% of the population carries H. pylori. In developed countries, the prevalence of infection is lower, however H. pylori remains to be the leading cause of stomach cancer.
How does H. Pylori cause Gastritis and Gastric cancer?
Pylori is usually transmitted in childhood and persists for life if untreated. It colonizes the stomach, where it is able to survive and thrive. This is made possible by unique properties and adaptations to survival within highly acidic environments of the human stomach. Its shape plays a crucial role in its survival; H. pylori is helix-shaped, which enables it to penetrate the stomach’s mucous lining and attach to the epithelial cells beneath. This not only shields the bacterium from acidic conditions but also places it close to the less acidic mucus layer near the stomach lining, providing a more hospitable environment. H. pylori has also got several mechanisms to neutralize the acid around it, the most notable being its ability to produce enzyme urease. It catalyzes the conversion of urea (naturally present in the stomach) to carbon dioxide and ammonia. The ammonia then reacts with the gastric acid to form ammonium, which helps buffer the stomach’s pH around the bacterium. This localized increase in pH protects H. pylori from the otherwise lethal acidity of the stomach, allowing it to colonize this challenging environment effectively. These adaptations not only aid its survival but also contribute to the pathogenic effects leading to gastric ulcers and increased risks of developing gastric cancer.
H. Pylori Symptoms
H. pylori causes persistent inflammation of the gastric mucosa, leading to frequent damage of the epithelial cells lining the stomach. This means that the cells need to be constantly regenerating, which increases the risk of mutations during DNA replication. This is exacerbated due to H. pylori’s ability to disrupt cellular pathways by activating oncogenes and inactivating tumor suppressor genes. H. pylori produces an oncoprotein CagA (cytotoxic associated gene A), which disrupts the Wnt pathway, which is crucial in cell regeneration, in gastric epithelial cells, compromising the proliferation and differentiation of gastric stem and progenitor cells and promoting carcinogenesis. This results in uncontrolled cell growth and accumulation of genetic abnormalities.
Diagnosing H. Pylori Infection
A variety of tests to diagnose H. pylori infection are now available. Histological examination of gastric tissue, culture, rapid urease testing, DNA probes, and PCR analysis, when used to test gastric tissue, all require endoscopy. During endoscopic biopsy, tissue samples are removed from the stomach lining to be tested for presence of H. pylori. It is highly accurate and can also assess the degree of stomach damage and the presence of cancerous changes.
Treating H. Pylori Infection
H. pylori treatment consists of a strong acid suppressant in various combinations with antibiotics and/or bismuth. The dramatic increase in resistance to key antibiotics used in H. pylori eradication demands antibiotic susceptibility testing, surveillance of resistance and antibiotic stewardship. The standard treatment involves a combination of two or three antibiotics (e.g., clarithromycin, amoxicillin, metronidazole) to overcome bacterial resistance, along with a proton pump inhibitor (PPI) to reduce stomach acid. This helps improve the antibiotics’ effectiveness and promotes healing of the stomach lining. Treatment typically lasts for two weeks. After completion, testing may be repeated to confirm that the infection has been successfully eradicated. However, in cases where complications such as ulcers have developed, additional treatments, including increased acid suppression or surgery, might be necessary.
Understanding the impact of Helicobacter pylori (H. pylori) infection is crucial due to its association with various serious stomach diseases. Increased awareness about how this bacterium is transmitted and its potential health consequences can lead to early detection and more effective management of related diseases.
If you or someone you know experiences persistent stomach discomfort, such as pain, bloating, nausea, or unexplained weight loss, it’s important to consult a healthcare provider. Early diagnosis and treatment of H. pylori infection can significantly reduce the risk of developing more severe gastrointestinal conditions. Don’t hesitate to seek medical advice to ensure your stomach health is maintained, and encourage others to do the same.
