Myometrial inflammation is thought to have a pivotal role in the onset of term and some forms of preterm labour. This is based on the comparison of samples taken from women undergoing term elective ...CS prior to the onset of labour with those taken from women in established labour. Consequently, it is not clear whether myometrial inflammation is a cause or a consequence of labour. Our objective is to test the hypothesis that myometrial inflammation is a consequence of the onset of labour. To test this hypothesis, we have obtained myometrial samples from women at various stages of pregnancy and spontaneous labour and studied the activation of the AP-1 (c-Jun) and NFκB (p65) systems, cytokine mRNA expression and protein levels and inflammatory cell infiltration and activation. We found that the activation of p65 declined from preterm to term not in labour samples and thereafter increased in early and established labour. Cytokine mRNA expression and protein levels increased in established labour only. Using flow cytometry of myometrial tissue, we found that the number of neutrophils did increase with the onset of labour, but on tissue section, these were seen to be intravascular and not infiltrating into the myometrium. These data suggest that myometrial inflammation is a consequence rather than a cause of term labour.
High throughput sequencing has previously identified differentially expressed genes (DEGs) and enriched signalling networks in human myometrium for term (≥37 weeks) gestation labour, when defined as ...a singular state of activity at comparison to the non-labouring state. However, transcriptome changes that occur during transition from early to established labour (defined as ≤3 and >3 cm cervical dilatation, respectively) and potentially altered by fetal membrane rupture (ROM), when adapting from onset to completion of childbirth, remained to be defined. In the present study, we assessed whether differences for these two clinically observable factors of labour are associated with different myometrial transcriptome profiles. Analysis of our tissue ('bulk') RNA-seq data (NCBI Gene Expression Omnibus: GSE80172) with classification of labour into four groups, each compared to the same non-labour group, identified more DEGs for early than established labour; ROM was the strongest up-regulator of DEGs. We propose that lower DEGs frequency for early labour and/or ROM negative myometrium was attributed to bulk RNA-seq limitations associated with tissue heterogeneity, as well as the possibility that processes other than gene transcription are of more importance at labour onset. Integrative analysis with future data from additional samples, which have at least equivalent refined clinical classification for labour status, and alternative omics approaches will help to explain what truly contributes to transcriptomic changes that are critical for labour onset. Lastly, we identified five DEGs common to all labour groupings; two of which (AREG and PER3) were validated by qPCR and not differentially expressed in placenta and choriodecidua.
Preterm labor (PTL) is the predominant cause of childhood morbidity and mortality. It has several phenotypes, each with a distinct etiology often involving inflammation. Here, in samples of ...reproductive tissues obtained in early PTL from women with phenotypically defined PTL, we examined the presence and distribution of inflammation and its relationship with prolabor gene expression. In chorioamnionitis (CA-PTL), cytokine protein concentrations were increased across all tissues; in idiopathic (I-PTL), the inflammatory changes were limited to the choriodecidua; inflammation was not a feature of placental abruption (PA-PTL). CA-PTL was associated with activation of p65 in the myometrium and AP-1 in the choriodecidua, and PA-PTL with CREB in the choriodecidua. In the myometrium, PGHS-2 mRNA level was increased in CA- and I-PTL; in the amnion, PGHS-2 mRNA level was higher in PA- and I-PTL, while in CA-PTL, OT, OTR mRNA, and CX-43 expression were increased. In the choriodecidua, PGHS-2 mRNA level was unchanged, but in CA and I-PTL, OT mRNA level were increased and OTR was reduced. These data show that CA-PTL is associated with widespread inflammation and prolabor gene expression. In contrast, in I-PTL, inflammation is limited to the choriodecidua, with discrete increases in PGHS-2 in the amnion and OT in the choriodecidua. Inflammation is not a feature of PA-PTL, which is associated with increased OT and OTR in the amnion. Summary Sentence These data show distinct patterns of gene expression in different types of PTL and, consequently, have important implications for both therapy and our understanding of PTL etiology.
High throughput sequencing has previously identified differentially expressed genes (DEGs) and enriched signalling networks in human myometrium for term (≥37 weeks) gestation labour, when defined as ...a singular state of activity at comparison to the non-labouring state. However, transcriptome changes that occur during transition from early to established labour (defined as ≤3 and >3 cm cervical dilatation, respectively) and potentially altered by fetal membrane rupture (ROM), when adapting from onset to completion of childbirth, remained to be defined. In the present study, we assessed whether differences for these two clinically observable factors of labour are associated with different myometrial transcriptome profiles. Analysis of our tissue ('bulk') RNA-seq data (NCBI Gene Expression Omnibus: GSE80172) with classification of labour into four groups, each compared to the same non-labour group, identified more DEGs for early than established labour; ROM was the strongest up-regulator of DEGs. We propose that lower DEGs frequency for early labour and/or ROM negative myometrium was attributed to bulk RNA-seq limitations associated with tissue heterogeneity, as well as the possibility that processes other than gene transcription are of more importance at labour onset. Integrative analysis with future data from additional samples, which have at least equivalent refined clinical classification for labour status, and alternative omics approaches will help to explain what truly contributes to transcriptomic changes that are critical for labour onset. Lastly, we identified five DEGs common to all labour groupings; two of which (AREG and PER3) were validated by qPCR and not differentially expressed in placenta and choriodecidua.
Systemic inflammatory responsiveness was studied in normal human pregnancy and its specific inflammatory disorder, pre-eclampsia. Compared with nonpregnancy, monocytes were primed to produce more ...TNF-alpha throughout normal pregnancy, more IL-12p70 in the first and second trimesters, and more IL-18 in the first trimester only. Intracellular cytokine measurements (TNF-alpha and IL12p70) showed little change by comparison. IFN-gamma production was suppressed in all three trimesters. In pre-eclampsia, IL-18 secretion was increased. Secreted but not intracellular measures of TNF-alpha and IL-12p70 were also further enhanced compared with normal pregnancy. Inhibition of IFN-gamma production was lost and involved both CD56(+) NK and CD56(-) lymphocyte subsets. We determined whether circulating syncytiotrophoblast microparticles (STBM) could contribute to these inflammatory changes. Unbound STBM could be detected in normal pregnancy by the second trimester and increased significantly in the third. They were also bound in vivo to circulating monocytes. Women with pre-eclampsia had significantly more circulating free but not cell-bound STBMs. STBMs prepared by perfusion of normal placental lobules stimulated production of inflammatory cytokines (TNF-alpha, IL12p70, and IL-18 but not IFN-gamma) when cultured with PBMCs from healthy nonpregnant women. Inflammatory priming of PBMCs during pregnancy is confirmed and is established by the first trimester. It is associated with early inhibition of IFN-gamma production. The inflammatory response is enhanced in pre-eclampsia with loss of the IFN-gamma suppression. Circulating STBMs bind to monocytes and stimulate the production of inflammatory cytokines. It is concluded that they are potential contributors to altered systemic inflammatory responsiveness in pregnancy and pre-eclampsia.
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