Tag Archives: microbiome

Microbiome in pediatric ulcerative colitis

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Alterations in the gastrointestinal tract microbiome may play an important role in many digestive conditions.  A recent article examines microbiome alterations in children with severe ulcerative colitis (UC) (Inflamm Bowel Dis 2012; 18: 1799-1808).

Stool samples from 26 healthy children and 27 children with severe UC were prospectively studied.  After DNA extraction, PCR amplification and microarray hybirdization were performed and analyzed.   None of the patients in the study had received antibiotics or probiotics in the preceding month.

Key findings:

  • There were substantial reductions in “richness,” diversity, and evenness of the gut microbiome in UC patients.  (Richness is a term used to reflect the number of detected phylospecies.)
  • There was a decrease in signal in almost all  phylospecies.
  • The number of phylospecies was reduced in UC (266 ± 69) vs controls (758 ± 3)
  • Steroid responders had even fewer phylospecies compared with responders (142 ± 49  vs. 338 ± 62)

It is not surprising that the stools from these children are much different.  The issues of causation and whether a snapshot of the microbiome diversity will have clinical relevance is not clear.  It is possible that antimicrobials may make an individual more susceptible to inflammatory bowel disease by altering the individual’s microbiome.

Related blog entries:

Eat your veggies…if you don’t want to get sick | gutsandgrowth

Why are we seeing so many more cases | gutsandgrowth

Eat your veggies…if you don’t want to get sick

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Maybe your mother was right –you should eat your vegetables!   For a long time, it has been known that dietary changes can be used to treat Crohn’s disease.  The specifics about what type of diet and the reasons for how diet promotes a healthy gastrointestinal tract are being unraveled.  A person’s diet affects their microbiome; and, a number of recent articles have highlighted the microbiome in both functional and nonfunctional disorders (see below).

An even more fascinating article is in last week’s New England Journal of Medicine (NEJM 2012; 366: 181).  This article discusses two publications which show how certain dietary components interact with intestinal immune receptors.

  • Kiss EA et al. Science 2011 October 27 (Epub ahead of print).
  • Li Y et al. Cell 2011; 147: 629-40.

This NEJM article implicates a typical ‘Western’ diet as a contributor to inflammatory bowel disease (IBD).  However, a diet high in vegetables may prevent or reduce inflammation.  One mechanism whereby vegetables affect the GI tract is through the AhR (aryl hydrocarbon) receptor.  Some vegetables, like broccoli, cabbage, and brussel sprouts, are natural ligands for this receptor.  A mouse model has shown that AhR deficiency “results in increased epithelial vulnerability, immune activation, and altered composition of the microbiota.”  In addition, AhR is down-regulated in the intestinal tissue of persons with IBD.  AhR ligands are associated with increased interleukin-22 which promotes intestinal integrity.

Additional work regarding the optimal diet are ongoing.  There has been an interest in a ‘carbohydrate specific diet.’  This year’s NASPGHAN meeting (abstract #48)  presented data on this diet from a retrospective study.  This poster described five patients on monotherapy (diet alone) and at 6 months –good results in four patients (80%).  A few prospective studies are underway; in fact, a prospective study with patients from our office will be presented at this year’s DDW.  Initial results look promising (personal communication from lead investigator, Stan Cohen).

Additional references:

  • -Gastroenterology 2010; 139: 1816, 1844.  Microbiome & affect on IBD vs mucosal homeostasis.
  • -J Pediatr 2010; 157: 240.  Microbiota in pediatric IBD -increased E coli and decreased F praunsitzil in IBD pts.
  • -Gastro 2011; 141: 28, 208.  GM-CSF receptor (CD116) defective expression & function in 85% of IBD pts. n=52.
  • -Scand J Gastro 2001; 36: 383-8.  Elemental & polymeric diets successful in maintaining remission in ~43% of adults with complete steroid withdrawal.
  • -Clin Gastro & Hepatology 2006; 4: 744.  10 weeks of exclusive modulen (along with clears) had 79% response rate (n=37).  Better histologic response than steroids.
  • -J Pediatr 2000; 136: 285. Nutritional treatment w polymeric diet is effective w/in 8 weeks in 32/37.
  • -JPGN 2000; 31: 3 & 8.  EN about as effective as steroids for primary Rx.
  • -Can J Gastroenterol 1998; 12(8):544-49. Patients, diets and preferences in
    a pediatric population with Crohn’s disease.
  • -Gastroenterology 1988; 94:603-610. Chronic intermittent elemental diet improves growth failure in  children with Crohn’s disease.
  • -JPGN 1989; 8:8-12. Nutritional support for pediatric patients with inflammatory bowel disease.
  • -J Pediatr 2000; 136: 285-91. The role of nutrition in treating pediatric Crohn’s disease in the new millennium.