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Published on: May 21, 2015
PP063. TLR-4 expression and pro-inflammatory cytokine production by peripheral blood monocytes from preeclamptic
M Romao1, J C Peracoli1, C F Bannwart-Castro1
1Gynecology and Obstetrics, Botucatu, Brazil.
Introduction:
Toll-like receptor (TLR)-4 and TLR-2 are involved in inflammatory response of monocytes. These cells are activated in pregnant women with preeclampsia (PE), and over-produce inflammatory cytokines. TLR4 may recognize endogenous ligands, the so-called danger signals released by damaged cells, leading to production of pro-inflammatory cytokines.
Objectives:
This study investigated TLR2 and TLR4 expression and cytokine production by monocytes from women with PE before and after stimulation with TLR ligands.
Methods:
Monocytes (5×10(5)cell/mL) were obtained from 32 preeclamptic (PE) and 20 normotensive (NT) pregnant women in the last trimester of pregnancy. TLR2 and TLR4 expression on monocyte surface was determined by flow cytometry in non-stimulated cells, and after 18h of culture with lipopysaccharide (LPS) and peptidoglycan (PG). TNF-α, IL-10 and IL-12p70 production by these cells stimulated or not with LPS or PG was evaluated by enzyme immunoassay. Results were analyzed by non-parametric tests with significance level set at 5%.
Results:
In the absence of stimulation, the basal TLR4 expression by monocytes detected by the median fluorescence intensity (MFI) was significantly higher in the PE group than in the NT group while no significant differences were observed between groups in relation to endogenous TLR2 expression. An increase in TLR4 MFIs was detected after monocytes from NT pregnant women were stimulated with LPS while TLR2 expression was increased after PG-stimulation. No alterations in TLR expression was detected after LPS or PG-stimulation in monocytes from patients with PE. Evaluation of endogenous cytokine levels in supernatant culture of monocytes showed higher concentrations of TNF-α and IL-12p70 in preeclamptic women in comparison with the NT group, whereas IL-10 values were significantly higher in NT pregnant women than in the PE group. In contrast, when monocytes were stimulated with the TLRs ligands LPS and PG, the release of TNF-α was significantly reduced, while IL-12p70 levels were significantly higher in women with PE compared to NT group. IL-10 production was similar in both groups studied.
Conclusion:
The basal up-regulation of TLR4 expression associated with endogenous high TNF-α and IL-12p70 production by monocytes from preeclamptic women confirms the activated profile of these cells by the disease process. These findings provide new insights into possible roles for TLRs in the pathogenesis of systemic inflammation detected in PE.
Financial Support:
FAPESP 2009/11924-3 and 2010/20207-0.
