Study of Glucagon- Like Peptide 1 in Irritable Bowel Syndrome

Abstract EN

Background : Irritable bowel syndrome (IBS) is the most common chronic gastrointestinal disorder, affecting about 20 % of the world’s population.

Chronic abdominal pain or discomfort relieved by defecation and associated with altered bowel habits are the mainstay in diagnosis.

The pathophysiology of IBS remains unknown.

This biopsychological disorder involves dysregulation of the nervous system, altered intestinal motility, and increased visceral sensitivity.

All of these result from dysregualtion of the bi-directional communication between the gut with its enteric nervous system and the brain (the brain-gut axis), modulated by various psychosocial and environmental factors (e.g.

infection, inflammation).

Also changes in the gut hormones and their effect on motility and visceral sensitivity play important role in IBS.

Glucagon-like peptide-I (7-36) amide (GLP-1) is an incretin hormone of the enter insular axis released rapidly after meals.

Despite the fact that GLP-1 secreting cells (L-cells) occur predominantly in the distal gut.

The importance of this hormone in controlling gut motility and postprandial blood glucose level is under great deal of research now.

Objective : The present work aimed to study GLP-1 levels in response to oral glucose load in patients meeting the criteria for diagnosis of IBS and presenting with symptoms of diarrhea versus those presenting with constipation.

Study Design: 30 participants will be included in the study, 10 patients with IBS mainly diarrhea, 10 patients with IBS mainly constipation and 10 healthy control subjects.

With inclusion criteria as follow : chronic or recurrent gastrointestinal symptoms characterized by abdominal pain, altered bowel habits and bloatedness for at least three months, not explained by structural or biochemical abnormalities.

Exclusion criteria : diabetes, inflammatory bowel disease, infection (giardia, amoebae, schistosoma), neoplasms, peptic ulcer, gall bladder diseases, malabsorption, menstruation and antidepressants, oral contraceptive.

All the participants will undergo through history taking, physical examination, and then will perform : oral glucose tolerance test (100) in which GLP-1 will be measured in fasting state, 30 minutes, and 120 minutes after oral glucose, CBC, ESR, serum albumin and prothrombin time, liver and kidney functions and spot stool analysis, occult blood in stool, flexible sigmoidoscopy and colonic biopsy when indicated.

Results : In the present study we found respectable difference in the fasting levels between IBS patients and controls, with the highest levels of GLP-1 in diarrhea predominant IBS (P < 0.0001).

Postprandial levels also showed respectable difference between the three groups with the highest levels still among IBS group, but this time was among constipation predominant IBS.

Also pattern of change in plasma GLP-1 in response to glucose ingestion varies among IBS patients showing abnormal response.

Conclusion : GLP-1 could play a role in the pathophysiology of IBS either by inducing dismotility of the colon or affecting the enteric or central nervous system.