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Monday, March 13, 2017

The stomach in health and disease

Abstract (as presented by the authors of the scientific work):

"The stomach is traditionally regarded as a hollow muscular sac that initiates the second phase of digestion. Yet this simple view ignores the fact that it is the most sophisticated endocrine organ with unique physiology, biochemistry, immunology and microbiology. All ingested materials, including our nutrition, have to negotiate this organ first, and as such, the stomach is arguably the most important segment within the GI tract. The unique biological function of gastric acid secretion not only initiates the digestive process but also acts as a first line of defence against food-borne microbes. Normal gastric physiology and morphology may be disrupted by Helicobacter pylori infection, the most common chronic bacterial infection in the world and the aetiological agent for most peptic ulcers and gastric cancer. In this state-of-the-art review, the most relevant new aspects of the stomach in health and disease are addressed. Topics include gastric physiology and the role of gastric dysmotility in dyspepsia and gastroparesis; the stomach in appetite control and obesity; there is an update on the immunology of the stomach and the emerging field of the gastric microbiome. H. pylori-induced gastritis and its associated diseases including peptic ulcers and gastric cancer are addressed together with advances in diagnosis. The conclusions provide a future approach to gastric diseases underpinned by the concept that a healthy stomach is the gateway to a healthy and balanced host. This philosophy should reinforce any public health efforts designed to eradicate major gastric diseases, including stomach cancer."

Covered topics (the letter size corresponds to the frequency of mentioning in the text):

Conclusions (as presented by the authors of the scientific work):

"Healthy stomach: future approach to gastric diseases

The stomach occupies the central role in orchestrating the digestive process, and this is frequently underestimated. Moreover, gastric acid secretion in the last decades has been seen as a ‘bystander’ with little function but with deleterious potential for itself and adjacent organs, the oesophagus and duodenum. As a consequence, the pharmacological approach has been towards the development of more potent drugs for acid inhibition. Due to the increasing awareness of GI functional disorders, the role of the stomach has been revisited in its role as site of origin for dyspeptic symptoms. More recently, attention has focused on the stomach for its control function in food intake and for contributing to maintenance of metabolic balance (figure 10).

The future approach to gastric diseases (box 3) is directed to maintaining a healthy stomach, which is free from discomfort, ulceration and the risk of complications and malignancy. The main challenge remains the elimination of H. pylori infection from individual patients and from populations. An estimated 20% of H. pylori-infected people will continue to suffer from overt clinical upper GI symptoms and complications over their lifetime, and some may develop extra-digestive diseases. The individual outcome of anyone infected with H. pylori cannot be predicted. Therefore, a public health approach should be directed towards ‘screen and treat’ strategies that will have to be adapted to the needs of different populations according to the prevalence of H. pylori infection and gastric cancer risk stratification. Gastric disease prevention programmes should be integrated with more comprehensive GI prevention strategies. The combination of H. pylori screening and eradication programmes with colorectal cancer screening is an initiative promoted and coordinated by the Healthy Stomach Initiative (HSI) (http://www.hsinitiative.org).

Gastric cancer is still a major challenge worldwide, and because detection is frequently made only at an advanced stage, mortality has remained high.216 ,217 Gastric cancer prevention programmes by H. pylori eradication have been shown of benefit in high-risk populations.193 The best results from gastric cancer prevention strategies are obtained when H. pylori eradication is performed before advanced atrophic gastritis with pre-neoplastic changes becomes established and thus implementation of H. pylori screening and treatment in early adulthood is required. Secondary prevention by H. pylori eradication following endoscopic resection of early gastric cancer has major limitations.218 With pre-neoplastic conditions such as atrophy and IM already present, carcinogenic pathways are more likely to progress in spite of the eradication of H. pylori infection. Future research will need to focus on unravelling mechanisms involved in progression from pre-neoplastic lesions to cancer.

The recent definition of H. pylori gastritis as an infectious disease by the Kyoto global consensus conference, January 2014, is expected to raise concern and engender support from regulatory authorities towards the global elimination of H. pylori infection and its serious sequelae.150

Despite these important indications and calls for a widespread approach to the eradication of H. pylori infection, there remain substantial challenges. The first includes achieving the ideal effective therapy without significant side effects and no antibiotic resistance. Such an ideal therapy is not yet available, and therefore, H. pylori eradication therapy, beyond the established specific clinical indications, should embark on selected screen and treat strategies. For the time being, these strategies will have to address populations with a high to moderate incidence of gastric cancer. The search for a ‘golden treatment bullet’ continues to remain one option while the second option is an intensified search for a vaccine.

Second, H. pylori infection may confer some benefits to those who do not have gastroduodenal symptoms, nor present with gastroduodenal disease or complications. The reduced prevalence of atopic diseases, such as asthma in patients infected with H. pylori up to young adulthood, requires intensive investigation to understand the mechanism of this phenomenon. Epidemiological and experimental evidence is still limited and cannot yet offer any conclusions about a causal relationship.93 ,219 ,220 Studies on the relationship of H. pylori gastritis will lead to better understanding of both local and systemic immune responses and their impact on gastric diseases.

In addition to the initiatives and strategies to eradicate H. pylori infection, studies are required to better understand the role of the stomach in food intake, accommodation, pre-digestion and the delivery of nutrient for intestinal digestion.38 Research should focus on ways to modulate gastric functions and their role as ‘weight watcher’ and their integration in the balance of hunger and satiety. Studies will need to address to what extent gastric acid should be inhibited and for how long during the 24 h period in patients who suffer from acid-related diseases. Moreover, it will be important to define just how much acid is required to preserve a ‘healthy’ gut microbiome. The role of the gastric microbiota in the presence and absence of H. pylori infection on the diversity of microbiota in the small bowel will be of enormous relevance in understanding and tackling gastric, hepatic and intestinal diseases.221–223

Last, but by no means least, education with effective presentation of new knowledge to the general public to ensure gastric health and prevent disease is a major task to be accomplished and the creation of the HSI for public awareness is a step in this direction."

Full-text access of the referenced scientific work:

Hunt RH, Camilleri M, Crowe SE, El-Omar EM, Fox JG, Kuipers EJ, Malfertheiner P, McColl KE, Pritchard DM, Rugge M, Sonnenberg A, Sugano K, Tack J. The stomach in health and disease. Gut. 2015 Oct;64(10):1650-68. doi:10.1136/gutjnl-2014-307595. Review. PubMed PMID: 26342014; PubMed Central PMCID: PMC4835810.


Prof. Atanas G. Atanasov (Dr. habil., PhD)

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