Dr Gerald Holtmann and colleagues from Australia tested whether irritable bowel syndrome (IBS) is characterized by an augmented cellular immune response with enhanced production of proinflammatory cytokines.
The researchers further aimed to explore whether symptoms and psychiatric comorbidity in IBS are linked to the release of proinflammatory cytokines.
The team characterized basal and Escherichia coli lipopolysaccharide-induced cytokine production in peripheral blood mononuclear cells.
The research team evaluated 55 IBS patients, and 36 healthy controls.
Peripheral blood mononuclear cells were isolated by density gradient centrifugation, and cultured for 24 hours with or without lipopolysaccharides.
|Tumor necrosis factor-α levels were associated with anxiety|
Cytokine production was measured by enzyme-linked immunosorbent assay.
The team assessed abdominal symptoms and psychiatric comorbidities by using the validated Bowel Disease Questionnaire.
The researchers also used the Hospital Anxiety and Depression Scale.
IBS patients showed significantly higher baseline tumor necrosis factor-α, interleukin-1β, and interleukin-6.
The team identified higher lipopolysaccharide-induced interleukin-6 levels in IBS patients.
The researchers found that all cytokine levels were significantly higher in diarrhea-predominant IBS patients.
In contrast, the team noted that constipation-predominant IBS patients showed increased lipopolysaccharide-induced interleukin-1β levels.
Baseline tumor necrosis factor-α levels were higher in patients reporting more than 3 bowel movements per day, urgency, watery stools and pain.
Lipopolysaccharide-induced tumor necrosis factor-α, and interleukin-6 levels were higher in patients reporting more than 3 bowel movements per day.The team observed that these cytokine levels were also higher patients reporting urgency, watery stools, and pain associated with diarrhea.
The researchers found that lipopolysaccharide-induced tumor necrosis factor-α production was associated with anxiety in patients with IBS.
Dr Holtmann's team concludes, “Patients with diarrhea-predominant IBS display enhanced proinflammatory cytokine release, and this may be associated with symptoms and anxiety.”