Effect of rleptin on cytokine gene expression in cord blood and adult peripheral blood T-cells and monocytes^≠.

≠<p>Results from RT-PCR performed on purified cb and adult CD3+ T-cells and CD14+ monocytes cultured for 8h ± rleptin. The numbers denote positive samples; in parentheses, the range of gene intensities in pixels for the positive samples (<b>^#</b>Students’ t-test, P<0.05). Culture, culture conditions; cb, cord blood; PB, peripheral blood; n, number of samples; CM, plain culture medium;</p>*<p>adult monocyte samples that did not express any of the cytokine genes tested in CM and responded to rleptin; rleptin did not affect the IL-10 expression of the 6 positive samples in CM (<b>^¥</b>).</p

Anthropometric characteristics of the newborns^#.

#<p>Summary statistics calculated separately for the subgroups SGA, AGA and LGA. Data are presented as mean (± standard deviation) with minimum and maximum values. PI, ponderal index: birthweight (g) ×100<b>/</b>height (cm)³; Head circ., head circumference.</p

Cytokine gene expression (mean ±%CV) by CBMC of 40 healthy neonates and PBMC of 20 adults.

<p>The cells were cultured for 8h in plain culture medium (CM) or with mitogens (P/I) or with recombinant leptin (leptin). The levels of expression were normalized according to β2m expression levels. Statistically significant differences are indicated by asterisks (***, P<0.001, compared with 2-way ANOVA).</p

Demographic characteristics of the neonates^*.

*<p>Data are presented as the frequency count and percentages.</p

Anthropometric characteristics of the mothers^*.

*<p>Data are presented as mean (± standard deviation) with minimum and maximum values.</p

Proposed model of leptin regulation of cytokine production by cord blood T-cells and monocytes.

<p>Leptin is produced by adipocytes (and other tissues including the placenta), binds to its receptor (OB-R) on T-cells and monocytes <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0040830#pone.0040830-Mouzaki1" target="_blank">[29]</a>, and directly activates them to express cytokines. T-cells express the Th0/Th1 cytokine genes IFN-γ and IL-2 and the Th2 cytokine gene IL-4, that mediate effector functions <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0040830#pone.0040830-Zhu1" target="_blank">[57]</a>, and monocytes express IL-10, a main anti-inflammatory cytokine that limits the immune response and prevents damage to the host <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0040830#pone.0040830-Couper1" target="_blank">[58]</a>. In infants with very high leptin levels, leptin stimulation of IFN-γ production by T-cells overrides IL-10 production by monocytes <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0040830#pone.0040830-Chomarat1" target="_blank">[59]</a>; in this milieu, a Th1 response predominates; in addition, IFN-γ may enhance cytokine stimulation of leptin synthesis by adipocytes <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0040830#pone.0040830-Rocha1" target="_blank">[51]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0040830#pone.0040830-Wong1" target="_blank">[52]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0040830#pone.0040830-Gerhardt1" target="_blank">[60]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0040830#pone.0040830-Trujillo1" target="_blank">[61]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0040830#pone.0040830-Simons1" target="_blank">[62]</a> and perpetuate the Th1 polarization.</p

Scatter plot of cord blood leptin levels vs birth weight to show the populations from which the study groups A, B and C were selected and analyzed further for serum cytokine levels.

<p>The black circle includes 19 neonates with mean leptin levels over the 90^th percentile (group A), the red circle includes 17 neonates with mean leptin levels around the 50^th percentile (group B) and the orange circle includes 20 neonates with mean leptin level below the 10^th percentile.</p

Leptin levels correlated with IFN-γ levels, r = 0.356, P<0.01 (Spearman’s r for non parametric values).

<p>There was no correlation between leptin and the other cytokines tested. Correlation is significant at the P<0.01 level (2-tailed).</p

Cord blood (ln)leptin levels in SGA, AGA and LGA neonates.

<p>Values show mean ± SD. Statistically significant differences are indicated by asterisks (*, P<0.05; **, P<0.01, compared with the Kruskal-Wallis test). The table shows the min. and max. values (ng/ml) and the number of subjects (n) per group (total, males, females).</p

Cord blood leptin levels in healthy neonates categorized by birth weight.

<p>Median serum leptin levels in 7 weight categories (g); each includes leptin values for the total sample, male and female infants. The table shows the min. and max. leptin values (ng/ml) and the number of subjects (n) per weight group (total, males, females).</p