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15th
World Congress Clinical Nutrition
19th
– 22nd September 2010 El Sokhna Resort - Egypt
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Copyright © 2010.
WCCN2010.COM
All rights reserved |
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Probiotics and
immunoregulation
Elena Mengheri
National Research Institute for Food
and Nutrition (INRAN), Rome, Italy
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Probiotics are defined as “live
microorganisms which when
administered in adequate amounts
confer a health benefit on the
host”. These bacteria may prevent or
ameliorate different diseases, such
as allergy and intestinal
inflammation, and reduce the changes
associated with age. Although the
exact mode of action of probiotics
is still largely unknown, the
immunoregulation plays a major role
through enhancement of the innate
and adaptive immune system,
including modulation of cytokines
and induction of regulatory T-cell
suppressive effects.
Probiotics may provide protection
against pathogen infection by
maintaining the membrane barrier,
and we showed that the protection
against pathogen induced membrane
damages was achieved through
cytokine mediated preservation of
correct organization of the tight
junctions and cytoskeleton
proteins.Dysregulated intestinal
immune responses towards commensal
bacteria is a major cause of the
pathogenesis of inflammatory bowel
diseases (IBD), and probiotics have
been shown to be protective against
IBD, depending on the strain and/or
mixture of such bacteria. In an
animal model of colitis, we showed
that a mixture of Lactobacillus
acidophylus La5 and Bifidobacterium
BB12 prevented intestinal
inflammation through regulation of
both innate and adaptive immune
response. We found an inhibition of
inflammatory cells infiltration into
gut mucosa, expansion of Treg
(CD4+CD25+Foxp3+) and Tr1
(CD4+IL-10+) cells in
intraepithelial lymphocytes (IELs),
inhibition of pro-inflammatory
cytokines (TNF-, MCP-1, IL-12 and
IFN-), induction of IL-10, and
increased apoptosis of
IELs.Probiotics may also improve the
age-associated immune disorders.
Changes in gut microbiota with a
decrease of bifidobacteria and at
less extent of lactobacilli, occur
during aging, and therefore
supplementation with probiotics has
been suggested to counteract the
immunosenescence process. Our
studies indicated that probiotic
administration induced a different
immunoregulation of T cells in IELs
and LPLs of old mice and a
modulation of regulatory T cells in
elderly.
Work partly supported by MiPAAF
grant, project Alieta
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