Chemistry Reference
In-Depth Information
for Le
x
, which is a unit contained in some human milk oligosaccharides,
suggesting that the unknown inhibitory milk components could be milk
oligosaccharides. The putative complex oligosaccharides with multiple Le
x
determinants may inhibit DC-SIGN-mediated interactions similar to the
multivalent binding hypothesis for selectins (Bode, 2006; Naaling, 2005).
The question of whether human milk oligosaccharides influence cytokine
production and activation of cord blood T cells has recently been investigated
(Eiwegger et al., 2004). Cord blood mononuclear cells from randomly chosen
healthy newborns were co-cultured for 20 days with acidic or neutral oligosac-
charides, and intracellular cytokine production and surface marker expression
of T cells were studied using flow cytometry. The authors used concentrations
of oligosaccharides (neutral human milk oligosaccharides, 10 mg/ml; acidic
human milk oligosaccharides, 1 mg/ml) that were considered by them to
mimic physiologic conditions, although these concentrations are considerably
lower than the calculated values of 100-200 mg/L for circulating human milk
oligosaccharides mentioned by Bode (2006). The acidic, but not the neutral
oligosaccharide fraction, increased the percentage of interferon-
-producing
CD3+CD4+ and CD3+CD8+ cells, of IL-13 production in CD3+CD8+ cells
and significantly elevated CD25+ expression in CD3+CD4+ cells. These
results showed that human milk oligosaccharides affect cytokine production
and activation of cord blood-derived T cells in vitro.Oligosaccharidesand,in
particular, acidic milk oligosaccharides may therefore influence lymphocyte
maturation in breast-fed newborns. The authors concluded that human milk
oligosaccharides can modulate the immune system of the maturing infant.
A recent study on rats showed that goat milk oligosaccharides have an
anti-inflammatory effect in the colon (Daddaowa et al., 2006). In this study,
colitis was induced by the hapten, trinitrobenzenesulfonic acid (TNBS). The
experimental rats (OS) were fed a diet containing 500 mg/kg per day of goat
milk oligosaccharides, from 2 days prior to the induction until day 6, after
which all the rats were killed, the entire colon was removed, opened and
scored for visible damage and then divided into several pieces for biochemical
determinations. When the OS rats were compared with control rats in which
colitis had been induced by TNBS but that had not been treated with oligo-
saccharides, it was found that the OS rats showed decreased anorexia,
reduced loss of body weight, reduced bowel wall thickening and less necrosis
of the colon. Biochemically, the colon of the rats had lower levels of inducible
oxide nitric synthase (iNOS), cyclooxygenase 2 (COX2), interleukin-1
and
mucin 3, as well as increased trefoil factor 3. These results showed that goat
milk oligosaccharides are anti-inflammatory when administered as a pre-
treatment in the TNBS model of rat colitis, most likely due to their action
as prebiotics resulting in favorable changes in the colonic bacterial flora.
Since
TNBS-induced
colitis
is
widely
used
as
a
preclinical
model
of
