A proteomic view of probiotic Lactobacillus rhamnosus GG

Review of the Literature
and thus help the host strengthen its innate
defence mechanisms (Schlee et al., 2008; Wehkamp
et al., 2004). Probiotics have also been
shown to enhance the integrity of the host
intestinal barrier; treatment of human colonic
cells with L. rhamnosus GG prevented injuries
in the epithelial cell barrier that were induced
by enterohemorrhagic E. coli (Johnson-Henry
et al., 2008), and L. acidophilus LB protected
human colonic cells from aspirin-induced
damage in tight junctions (Montalto et al.,
2004).
Submucosal eff ects include the eff ects of
probiotics on the host immune system. Probiotics
have been shown to improve the intestine’s
immunological barrier functions and
alleviate the intestinal infl ammatory response
by mechanisms that include diverse effects
on immune activation, cytokine production,
immunomodulation, and infl ammation (Delcenserie
et al., 2008; Wells, 2011).
1.1.1.2. Main proper� es of probio� c
bacteria
To be suitable for probiotic use, a bacterial
strain should have certain characteristics.
It should survive the passage through the
GIT and thus be resistant to GIT conditions,
including acidic pH and bile acids (Bezkorovainy,
2001; Fuller, 1989). Th e safety of the
strain must be evident (EFSA, 2008; FAO/
WHO, 2002; Fuller, 1989), and strains of
human origin are usually preferred to achieve
host-specifi c probiotic eff ects (Ouwehand et
al., 2002). Th e ability to adhere to intestinal
mucosa is a desired property of a probiotic
because close contact and prolonged colonization
may intensify the favorable effects
of probiotics (Ouwehand et al., 2002). Good
technological properties are also important
for a strain to be used in a commercial probiotic
product; the strain should be suitable
2
for large-scale cultivation, remain viable and
stable under storage, and should not confer
an unpleasant taste on the product (Saarela et
al., 2000). Naturally, a probiotic strain also has
to impair benefi cial health eff ects to the host
(FAO/WHO, 2002; Fuller, 1989).
1.1.1.3. Health-benefi cial eff ects of
probio� cs
Th e potential health eff ects of probiotics have
been studied for several diseases and conditions
using a variety of diff erent strains, and
varying results have been achieved. Th e bestproven
health benefit for several probiotic
strains is the reduction of the risk of diarrhea
(e.g., antibiotic-associated and traveler’s diarrhea)
and the shortening of diarrheal episodes
(Hickson et al., 2007; Minocha, 2009; Ouwehand
et al., 2002; Saxelin et al., 2005; Weichselbaum,
2009). A meta-analysis of 34 blinded,
randomized, placebo-controlled trials studying
the eff ect of diff erent probiotics (mainly
Lactobacillus strains) in the prevention of
acute diarrhea showed that probiotics signifi -
cantly reduced antibiotic-associated diarrhea
by 52% and acute diarrhea of various causes
by 34% (Sazawal et al., 2006). Other diseases
of the gut may also be alleviated with probiotics.
A meta-analysis of twenty randomized,
controlled, blinded trials showed that probiotic
use may be associated with an improvement
in irritable bowel syndrome symptoms compared
to placebo (McFarland & Dublin, 2008).
The use of probiotics may be related to the
relief of constipation (Koebnick et al., 2003;
Weichselbaum, 2009) and lactose intolerance
(Vesa et al., 2000). Probiotics may increase
host immune defenses and thus decrease the
frequency or duration of infections like the
common cold (de Vrese et al., 2005; Minocha,
2009; Weichselbaum, 2009; Weizman et al.,
2005). In a double-blind, randomized trial, the