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
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”.
For example• The oral administration of live Lactobacillus
rhamnosus strain GG significantly reduce the
number of cases of nosocomial diarrhoea in young
children.
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.
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.
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.
Theories exist regarding probiotic
preparations:
Several theories exist regarding probiotic preparations.
These include:
• Stimulation of protective cytokines including IL-10 and
TGFβ.
• 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).
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.
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.
• 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 VSL#3 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.
• 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 doubleblind fashion in 103 patients for 12 weeks. Relapse
rates were 11% for mesalazine and 16% for E. coli.
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.
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.
• 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.
• 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.
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.
• Probiotic was inefficient as primary therapy for the
clinical improvement of pouch inflammation.
• Treatment with VSL#3 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.
Conclusion
• Probiotic preparation (VSL#3) 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.