Irritable bowel syndrome: diagnosis and pathogenesis

Area of Science:

• Gastroenterology
• Neurogastroenterology
• Biomarker Research

Background:

• Irritable bowel syndrome (IBS) is a prevalent gastrointestinal disorder significantly impacting patient quality of life and imposing economic burdens.
• Current IBS diagnosis relies on symptom assessment (Rome III criteria) and invasive procedures like gastroscopy and colonoscopy.
• The multifactorial pathogenesis of IBS involves genetics, diet, microbiota, low-grade inflammation, and gut neuroendocrine system (NES) disturbances.

Purpose of the Study:

• To explore the role of the gut neuroendocrine system (NES) in IBS pathogenesis.
• To identify potential biomarkers for IBS diagnosis.
• To understand the contribution of low-grade inflammation and NES alterations in specific IBS subtypes like post-infectious IBS (PI-IBS) and inflammatory bowel disease-associated IBS (IBD-IBS).

Main Methods:

• Review of diagnostic criteria for IBS, including Rome III criteria.
• Assessment of duodenal chromogranin A cell density as a potential diagnostic biomarker.
• Analysis of proposed etiological factors in IBS, including genetics, diet, microbiota, inflammation, and NES function.
• Examination of pathological findings in PI-IBS and IBD-IBS patients.

Main Results:

• Duodenal chromogranin A cell density shows promise as a biomarker for IBS diagnosis.
• A hypothesis suggests that altered gut NES leads to characteristic IBS symptoms like abnormal GI motility, secretions, and sensation.
• Low-grade mucosal inflammation and NES abnormalities are observed in PI-IBS and IBD-IBS patients.

Conclusions:

• The gut neuroendocrine system (NES) plays a central role in IBS pathogenesis, potentially influenced by genetic, dietary, microbial, and inflammatory factors.
• Duodenal chromogranin A cell density is a potential biomarker for IBS.
• Inflammation and NES alterations are significant in specific IBS subtypes, highlighting the complexity of the disorder.