Probiotics: An overview and their role in inflammatory bowel disease

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Probiotics An overview and their role in
inflammatory bowel disease

• Presented by
• Dr. Nazia Haque
• MPhil(2nd part student)
• Department of microbiology, MMC
• NEW HORIZON
• Year 2007 Volume 13 Issue 3
  Page 150-152

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Introduction

• The term "probiotic" meaning 'for life' was first
  coined in the 1960s by Lilly and Stillwell.
• Probiotics were defined as microorganisms proven
  to exert health-promoting influences in humans
  and animals.
• Probiotics were recently redefined by an expert
  group to be 'live microorganisms which when
  administered in adequate amounts confer a health
  benefit on the host'.
• Simplified definition of Probiotics as live,
  nonpathogenic bacteria that may be effective in
  the treatment or prevention of certain human
  diseases.

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• For example-
• The oral administration of live Lactobacillus
  rhamnosus strain GG significantly reduce the
  number of cases of nosocomial diarrhoea in young
  children.

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Beneficial effect of Probiotic

• Possible beneficial effect are
• Either in providing colonization resistance by
  which the non-pathogen excludes the pathogen from
  binding sites on the mucosa or
• Enhancing the immune response against the
  pathogen or
• In reducing the inflammatory response against the
  pathogen.

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Commonly Used Probiotic Organisms

• Two main genera of GP bacteria(Lactobacillus
  Bifidobacterium) are used extensively as
  probiotics.
• Other probiotics such as Escherichia ,
  Enterococcus Saccharomyces are also available
  in the market.
• Probiotic effects are strain-specific which means
  a beneficial effect produced by one strain cannot
  be assumed to be provided by another strain, even
  when it belongs to the same species.

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Possible Mechanisms of Benefit

• Mechanisms for the benefits of probiotics are
  incompletely understood. However, three general
  benefits have been described
• 1. Suppression of growth or epithelial
  binding/invasion by pathogenic bacteria
• 2. Improvement of intestinal barrier function
• 3. Modulation of the immune system.

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Theories exist regarding probiotic preparations

• Several theories exist regarding probiotic
  preparations. These include
• Stimulation of protective cytokines including
  IL-10 and TGFß.
• Suppression of pro-inflammatory cytokines such as
  TNF in the mucosa of patients with pouchitis and
  Crohn's disease.
• Limit the migration of TH1 cells in inflammed
  colon tissue in inflammatory bowel disease (IBD).
  

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Role of Probiotics in IBD

• It has been suggested that GI microflora are
  involved in the pathogenesis of inflammatory
  bowel diseases in genetically susceptible
  subjects.
• In support of this hypothesis is the observation
  that there is an increase in the number of
  microorganisms and a change in the various
  populations of normal flora in IBD patients.
• Interactions between the commensal microflora and
  the intestinal mucosa stimulate inflammatory
  activity.

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Probiotics in Ulcerative Colitis

• Various probiotic species have shown promise in
  the treatment of ulcerative colitis in small
  studies.
• Although a clear clinical benefit remains to be
  established. Prevention of relapse is more
  thoroughly documented than the treatment of
  active disease.

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• The following are illustrative controlled trials
• E. coli was as effective as low-dose
  5-aminosalicylic acid (5-ASA) in preventing
  relapse of ulcerative colitis.
• The combination of VSL3 plus balsalazide was
  slightly more effective than balsalazide or
  mesalazine alone in mild-to-moderate ulcerative
  colitis.
• The combination of a prebiotic (food intended to
  promote the growth of certain bacteria in the
  intestines) and a probiotic ( Bifidobacterium)
  was associated with improvement in histologic
  scores and immune activation in a one-month
  randomized controlled trial.

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• Lactobacillus more effective than standard
  treatment in patients with quiescent ulcerative
  colitis.
• A product containing B. breve , B. bifidum and L.
  acidophilus has been evaluated as a dietary
  adjunct in the treatment of ulcerative colitis.
• During the one-year duration of the study,
  exacerbation of symptoms occurred in three of 11
  patients in the supplemented group and in nine of
  ten patients in the placebo group but no
  difference was seen in the colonoscopic findings.
  
• The study by Kruis et al . was performed in a
  double-blind fashion in 103 patients for 12
  weeks. Relapse rates were 11 for mesalazine and
  16 for E. coli.

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In conclusion

• The benefits of probiotics for maintenance
  therapy in ulcerative colitis are still regarded
  as weak evidence since the effect is comparable
  with placebo.

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Probiotics in Crohn's Disease

• Probiotics are being investigated actively in the
  management of CD. Some of the more important
  studies
•  Preventive effect of Lactobacillus on the
  appearance of recurrent lesions of CD after
  surgery.

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• A combination of three Bifidobacterium species,
  four Lactobacillus species and S.salivarius ssp.
  has been evaluated for the prevention of
  recurrent inflammation after surgery.
• The patients either received a nonabsorbable
  antibiotic (rifaximin) for three months followed
  by nine months' intake of the probiotic.
• After one year, there was a significantly lower
  rate of severe endoscopic recurrence in patients
  treated with the antibiotic and probiotic
  combination.

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• Patients with active colonic CD were treated with
  prednisolone on a standard schedule and were also
  randomized to receive E. coli.
• Patients in the two groups had similar rates of
  remission but patients treated with prednisolone
  and E. coli had fewer relapses than patients in
  the placebo group.

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Probiotics and Pouchitis

•  Pouchitis is a nonspecific inflammation of the
  ileal reservoir after ileal-anal anastomosis for
  ulcerative colitis.
• Disturbances in the intestinal micro flora may be
  the triggering factor in its pathogenesis.

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• Probiotic was inefficient as primary therapy for
  the clinical improvement of pouch inflammation.
• Treatment with VSL3 was considered effective
  also in the prevention of acute pouchitis after
  surgery. Eight out of 20 patients treated with
  placebo and two of 20 treated with the probiotic
  product had an episode of acute pouchitis within
  one year.

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Conclusion

• Probiotic preparation (VSL3) containing 5 x 10
  per gram of four strains of Lactobacilli , three
  strains of Bifidobacteria and one strain of
  Streptococcus salivarius subspecies thermophilus
  may be effective in the prevention of pouchitis.