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An Assessment of Cognitive Function in Irritable Bowel Syndrome

The recruitment status of this study is unknown. The completion date has passed and the status has not been verified in more than two years.
Verified February 2011 by University College Cork.
Recruitment status was:  Recruiting
Science Foundation of Ireland
American Neurogastroenterology and Motility Society
Information provided by:
University College Cork Identifier:
First received: February 24, 2011
Last updated: NA
Last verified: February 2011
History: No changes posted

Irritable bowel syndrome (IBS) is a common disorder affecting up to 20% of the general population. Despite the prevalence of the disorder, it remains poorly understood. This is reflected in a symptom based diagnostic scheme, the lack of a suitable biological marker and inadequate treatment options. Current knowledge suggests the disorder is as a result of a dysregulated brain-gut axis, a complex construct describing the bidirectional communication systems underpinning normal gastrointestinal functioning.

The investigators hypothesize here that the disruption of this brain-gut axis is facilitated by an increased degradation of tryptophan along the kynurenine pathway. This metabolic abnormality has the potential to impact on both GI and CNS signaling through its effects on serotonergic signaling and the impact of metabolites like kynurenic acid and quinolinic acid on cognitive processes respectively.

Previous data from our laboratory indicated increased tryptophan degradation in IBS patients and suggested the metabolites produced as putative biological markers of the condition. In this study the investigators aim to reconcile cognitive impairment in IBS with GI and CNS symptom severity and kynurenine pathway metabolites.

The investigators will establish these baseline measures in IBS compared to control subjects. A battery of cognitive assessments will be carried out using a computerized testing system. Standardized rating scales will be used to assess GI and CNS symptom severity. GC-MS/MS, a recently acquired technology platform in our laboratory, will be used to quantify plasma quinolinic acid levels.

Irritable Bowel Syndrome

Study Type: Observational
Study Design: Observational Model: Case Control
Time Perspective: Cross-Sectional
Official Title: Kynurenine Pathway Metabolites as Novel Translational Biological Markers of Irritable Bowel Syndrome: Relationship to Gastrointestinal Function, Cognition and Co-morbid Depression

Further study details as provided by University College Cork:

Primary Outcome Measures:
  • CANTAB Assessments [ Time Frame: Baseline ]
    Cognitive assessments using CANTAB, a computerised cognitive assessment package

  • IBS Symptom Severity [ Time Frame: Baseline ]
    As assessment of IBS symptom severity using validated questionnaires

  • Kynurenine Pathway Metabolies [ Time Frame: Baseline ]
    Plasma tryptophan, kynurenine, kynurenic acid, quinolinic acid

  • Glucocorticoids [ Time Frame: Baseline ]
    Plasma/Salivary Cortisol

  • Cytokines [ Time Frame: Baseline ]
    Plasma Cytokine concentrations

  • Psychiatric Comorbidity [ Time Frame: Baseline ]
    Psychiatric comorbidity will be assessed according to DSM-IV criteria

Secondary Outcome Measures:
  • Sleep Quality [ Time Frame: Baseline ]
    The potential confounding effect of sleep quality will be established using the Pittsburg Sleep Quality Index

Biospecimen Retention:   Samples With DNA
Plasma Serum Saliva

Estimated Enrollment: 85
Study Start Date: January 2011
Estimated Study Completion Date: January 2012
Estimated Primary Completion Date: December 2011 (Final data collection date for primary outcome measure)
Healthy Control Subjects
IBS Group
Subjects diagnosed with IBS

  Show Detailed Description


Ages Eligible for Study:   18 Years to 65 Years   (Adult)
Sexes Eligible for Study:   Female
Accepts Healthy Volunteers:   Yes
Sampling Method:   Non-Probability Sample
Study Population

IBS Patients will be recruited from a university database of IBS patients, comprising people who have previously either attended gastroenterology clinics at Cork University Hospital or responded to direct advertisement regarding participation in IBS research.

Healthy Controls will be recruited from responders to a direct advertisement regarding participation in IBS research


Inclusion Criteria:

  • Be able to give written informed consent,
  • Be between the ages of 18 and 65 years of age,
  • Must be female,
  • IBS patients must have a confirmed clinical diagnosis IBS using Rome III criteria
  • Healthy subjects must be in generally good health as determined by the investigator
  • Pregnant women
  • Individuals with known lactose intolerance or immunodeficiency will be excluded

Exclusion Criteria:

  • Are less than 18 and greater than 65 years of age,
  • Have a significant acute or chronic coexisting illness [cardiovascular, gastrointestinal, immunological, or any condition which contraindicates, in the investigators judgement, entry to the study].
  • Having a condition or taking a medication that the investigator believes would interfere with the objectives of the study, pose a safety risk or confound the interpretation of the study results; to include, anti-psychotics and steroids (in healthy and IBS subjects).
  • Have evidence of immunodeficiency; bleeding disorder or coagulopathy.
  • Subjects may not be receiving treatment involving experimental drugs. If the subject has been in a recent experimental trial, these must have been completed not less than 30 days prior to this study.
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Please refer to this study by its identifier: NCT01304355

Contact: Gerard Clarke, PhD 003535214901415

Cork University Hospial Recruiting
Cork, Ireland
Contact: Gerard Clarke, PhD    00353214901415   
Principal Investigator: Gerard Clarke, PhD         
Principal Investigator: Timothy G Dinan, Professor         
Principal Investigator: John F Cryan, PhD         
University College Cork Recruiting
Cork, Ireland
Contact: Gerard Clarke, PhD    00353214901415   
Principal Investigator: Gerard Clarke, PhD         
Principal Investigator: Timothy G Dinan, Professor         
Principal Investigator: John F Cryan, PhD         
Sponsors and Collaborators
University College Cork
Science Foundation of Ireland
American Neurogastroenterology and Motility Society
Principal Investigator: Gerard Clarke, PhD University College Cork
Principal Investigator: Timothy G Dinan, Professor University College Cork
Principal Investigator: John F Cryan, PhD University College Cork
  More Information

Additional Information:

Responsible Party: Professor Ted Dinan, University College Cork Identifier: NCT01304355     History of Changes
Other Study ID Numbers: APC024-GC/ANMS
Study First Received: February 24, 2011
Last Updated: February 24, 2011

Keywords provided by University College Cork:
Kynurenine Pathway

Additional relevant MeSH terms:
Irritable Bowel Syndrome
Pathologic Processes
Colonic Diseases, Functional
Colonic Diseases
Intestinal Diseases
Gastrointestinal Diseases
Digestive System Diseases processed this record on May 25, 2017