Hypothalamic-pituitary-gut axis dysregulation in irritable bowel syndrome: plasma cytokines as a potential biomarker?

Gastroenterology. 2006 Feb;130(2):304-11. doi: 10.1053/j.gastro.2005.11.033.


Background & aims: Irritable bowel syndrome (IBS) is a functional disorder with an etiology that has been linked to both psychological stress and infection. The primary aim of this study was to examine the hypothalamic-pituitary-adrenal axis in patients with IBS and to relate such response to plasma cytokine profiles.

Methods: A total of 151 subjects, 76 patients and 75 controls, were recruited. The patients with IBS were diagnosed according to Rome II criteria. Forty-nine patients and 48 matched controls had cytokine levels measured, and a subset of 21 patients and 21 controls also underwent a corticotropin-releasing hormone (CRH) stimulation test with plasma levels of adrenocorticotropic hormone (ACTH) and cortisol measured. The remaining 27 patients and 27 controls underwent a dexamethasone (1 mg) challenge.

Results: Cortisol and the proinflammatory cytokines interleukin (IL)-6 (together with its soluble receptor) and IL-8 were elevated in all IBS subgroups (diarrhea predominant, constipated, and alternators), although the elevation was most marked in the constipated subgroup. There was no alteration in the anti-inflammatory cytokine IL-10. Following CRH infusion, an exaggerated release of both ACTH and cortisol was observed in patients with IBS. There was a significant correlation between the ACTH response (deltaACTH) and the IL-6 levels. A similar relationship existed between the deltaACTH/deltacortisol ratio and the IL-6 levels. Dexamethasone suppression of cortisol was similar in patients and controls.

Conclusions: IBS is characterized by an overactivation of the hypothalamic-pituitary-adrenal axis and a proinflammatory cytokine increase.

Publication types

  • Comment
  • Comparative Study
  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adrenocorticotropic Hormone / blood
  • Adult
  • Alcohol Drinking
  • Biomarkers / blood
  • Cytokines / blood*
  • Dexamethasone
  • Female
  • Humans
  • Hypothalamo-Hypophyseal System / physiopathology*
  • Interleukin-10 / blood
  • Interleukin-6 / blood
  • Interleukin-8 / blood
  • Intestines / physiopathology*
  • Ireland
  • Irritable Bowel Syndrome / blood
  • Irritable Bowel Syndrome / physiopathology*
  • Male
  • Pain
  • Reference Values


  • Biomarkers
  • Cytokines
  • Interleukin-6
  • Interleukin-8
  • Interleukin-10
  • Dexamethasone
  • Adrenocorticotropic Hormone