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The
fruit of the date palm (Phoenix dactylifera L.) is a rich source of dietary
fibre and polyphenols. We have investigated gut bacterial changes induced by
the whole date fruit extract (digested date extract; DDE) and its
polyphenol-rich extract (date polyphenol extract; DPE) using faecal,
pH-controlled, mixed batch cultures mimicking the distal part of the human
large intestine, and utilising an array of microbial group-specific 16S rRNA
oligonucleotide probes. Fluorescence microscopic enumeration indicated that
there was a significant increase in the growth of bifidobacteria in response
to both treatments, whilst whole dates also increased bacteroides at 24 h and
the total bacterial counts at later fermentation time points when compared
with DPE alone. Bacterial metabolism of whole date fruit led to the
production of SCFA, with acetate significantly increasing following bacterial
incubation with DDE. In addition, the production of flavonoid aglycones
(myricetin, luteolin, quercetin and apigenin) and the anthocyanidin petunidin
in less than 1 h was also observed. Lastly, the potential of DDE, DPE and
metabolites to inhibit Caco-2 cell growth was investigated, indicating that
both were capable of potentially acting as antiproliferative agents in vitro,
following a 48 h exposure. This potential to inhibit growth was reduced
following fermentation. Together these data suggest that consumption of date
fruits may enhance colon health by increasing beneficial bacterial growth and
inhibiting the proliferation of colon cancer cells. This is an early
suggestion that date intake by humans may aid in the maintenance of bowel
health and even the reduction of colorectal cancer development.
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BACKGROUND:
Ageing increases risk of respiratory infections and
impairs the response to influenza vaccination. Pre- and probiotics offer an
opportunity to modulate anti-viral defenses and the response to vaccination
via alteration of the gut microbiota. This study investigated the effect of a
novel probiotic, Bifidobacterium longum bv. infantis CCUG 52,486, combined
with a prebiotic, gluco-oligosaccharide (B. longum + Gl-OS), on the response
to seasonal influenza vaccination in young and older subjects in a double-blind,
randomized controlled trial, taking into account the influence of
immunosenescence markers at baseline.
RESULTS:
Vaccination resulted in a significant increase in
total antibody titres, vaccine-specific IgA, IgM and IgG and seroprotection
to all three subunits of the vaccine in both young and older subjects, and in
general, the increases in young subjects were greater. There was little
effect of the synbiotic, although it tended to reduce seroconversion to the
Brisbane subunit of the vaccine and the vaccine-specific IgG response in
older subjects. Immunological characterization revealed that older subjects
randomized to the synbiotic had a significantly higher number of senescent
(CD28(-)CD57(+)) helper T cells at baseline compared with those randomized to
the placebo, and they also had significantly higher plasma levels of anti-CMV
IgG and a greater tendency for CMV seropositivity. Moreover, higher numbers
of CD28(-)CD57(+) helper T cells were associated with failure to seroconvert
to Brisbane, strongly suggesting that the subjects randomized to the
synbiotic were already at a significant disadvantage in terms of likely
ability to respond to the vaccine compared with those randomized to the
placebo.
CONCLUSIONS:
Ageing was associated with marked impairment of the
antibody response to influenza vaccination in older subjects and the
synbiotic failed to reverse this impairment. However, the older subjects
randomized to the synbiotic were at a significant disadvantage due to a
greater degree of immunosenscence at baseline compared with those randomized
to the placebo. Thus, baseline differences in immunosenescence between the
randomized groups are likely to have influenced the outcome of the
intervention, highlighting the need for detailed immunological
characterization of subjects prior to interventions.
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ملخص المشاركة:
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Bifidobacterium longum bv. infantis CCUG52486 has immunomodulatory properties, which
are strongly influenced by ageing. The
PRIMAGE (Probiotics, Immunity and AGEing) study examined the influence of
this probiotic in combination with glucooligosaccharide on the immune
response to influenza vaccination in young and older subjects; effects on the
regulatory CD4+CD25high T-cell response are reported
here.
58 young (18-35y) and 54 older (60-85y)
subjects were treated with B. longum + Gl-OS, or with placebo (maltodextrin) for 8 weeks in total, with the
influenza vaccination (2010-2011 northern hemisphere) being given at 4 weeks.
Blood samples were taken at weeks 0, 4, 6 and 8. T-cells were analysed by
flow cytometry.
The
antibody response to influenza vaccination was lower in older subjects. B. longum + Gl-OS significantly
reduced the antibody response to the Brisbane subunit in older subjects;
however, it significantly decreased the duration of flu-like symptoms in the
6 month period following vaccination in the older subjects. B. longum +Gl-OS resulted in a greater
increase in the percentage and absolute number of CD25highCD4+
T-cells after vaccination in older subjects compared with placebo. This
increase was not correlated with the antibody response to influenza
vaccination but was associated with lower incidence of flu and was inversely
correlated with the duration of flu illness.
In conclusion, ageing impaired the antibody
response to influenza vaccination. The B.
longum + Gl-OS reduced the antibody response to the Brisbane subunit in
older subjects, but reduced the duration of flu-like symptoms and enhanced
the production of CD25highCD4+ T-cells after
vaccination
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