Relationship of cytokines, oxidative stress and GI motility with bacterial overgrowth in ulcerative colitis patients

J Crohns Colitis. 2014 Aug;8(8):859-65. doi: 10.1016/j.crohns.2014.01.007. Epub 2014 Jan 21.


Background: Ulcerative colitis (UC) is idiopathic, chronic and relapsing inflammatory bowel disease. Factors which initiate and perpetuate UC are not well understood. It is still unclear if any relationship exists between cytokines, oxidative stress, gastrointestinal (GI) motility, and small intestinal bacterial overgrowth (SIBO) in UC patients.

Goals: To examine the relationship between these factors among UC patients.

Methods: A total of 120 UC patients and 125 age and sex matched controls with no GI symptoms were enrolled. Plasma levels of IL-6, IL-8, TNF-α and IL-10 were measured in all subjects by using ELISA. Lipid peroxidation (LPO) and reduced glutathione (GSH) were measured by standard methods. Orocecal transit time (OCTT) and SIBO were measured by lactulose and glucose hydrogen breath tests respectively.

Results: Out of the 120 UC patients, 74 were male with mean±SD age of 45.6±17.5years. Plasma levels of IL-6, IL-8, TNF-α and IL-10 in UC patients were significantly higher (p<0.01) as compared to controls. LPO in UC patients was significantly increased (p<0.01) while GSH was significantly decreased (p<0.01) as compared to controls. OCTT and SIBO were significantly higher in UC patients as compared to controls. UC patients with elevated inflammatory cytokines showed delayed OCTT and increased SIBO. It was also observed that there was a significant correlation between SIBO with IL-6, IL-8, TNF-α, and IL-10, LPO and GSH.

Conclusion: This study indicates that increase in cytokines and decrease in anti-oxidants in UC patients would have resulted in oxidative stress causing delayed GI motility leading to SIBO.

Keywords: Cytokines; Orocecal transit time; Oxidative stress; Small intestinal bacterial overgrowth; Ulcerative colitis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Case-Control Studies
  • Colitis, Ulcerative / etiology*
  • Colitis, Ulcerative / physiopathology
  • Cytokines / blood
  • Cytokines / physiology*
  • Enzyme-Linked Immunosorbent Assay
  • Gastrointestinal Motility / physiology*
  • Gastrointestinal Transit / physiology
  • Humans
  • Interleukin-10 / blood
  • Interleukin-10 / physiology
  • Interleukin-6 / blood
  • Interleukin-6 / physiology
  • Interleukin-8 / blood
  • Interleukin-8 / physiology
  • Lipid Peroxidation / physiology
  • Middle Aged
  • Oxidative Stress / physiology*
  • Tumor Necrosis Factor-alpha / blood
  • Tumor Necrosis Factor-alpha / physiology
  • Young Adult


  • Cytokines
  • Interleukin-6
  • Interleukin-8
  • Tumor Necrosis Factor-alpha
  • Interleukin-10