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Intra-amniotic (IA) inflammation is associated with significant morbidities for both the mother and the fetus. Prior studies have illustrated many of the effects of IA inflammation on the uterine lining (decidua) and membranous layers of the placenta at the fetal-maternal interface. However, much less is known about the immunological response occurring within the villous placenta. Using a rhesus macaque model of lipopolysaccharide (LPS)-induced IA inflammation, we showed that pregnancy-matched choriodecidua and villi have distinct immunological profiles in rhesus pregnancies. In the choriodecidua, we show that the abundance of neutrophils, multiple populations of antigen-presenting cells, and two populations of natural killer (NK) cells changes with prenatal IA LPS exposure. In contrast, in immune cells within the villous placenta we observed alterations in the abundance of B cells, monocytes, and CD8 T cells. Prior work has illustrated that IA inflammation leads to an increase in tumor necrosis factor alpha (TNFα) at the fetal-maternal interface. In this study, pretreatment with a TNFα blockade partially reversed inflammation in the placental villi. Furthermore, we report that immune cells in the villous placenta sensed LPS during our experimental window, and subsequently activated T cells to produce proinflammatory cytokines. Moreover, this study is the first report of memory T cells in third-trimester non-human primate placental villi and provides evidence that manipulation of immune cells in the villi at the fetal-maternal interface should be considered as a potential therapeutic target for IA inflammation.

Human parturition at term and preterm is an inflammatory process synchronously executed by both fetomaternal tissues to transition them from a quiescent state t an active state of labor to ensure delivery. The initiators of the inflammatory signaling mechanism can be both maternal and fetal. The placental (fetal)‐maternal immune and endocrine mediated homeostatic imbalances and inflammation are well reported. However, the fetal inflammatory response (FIR) theories initiated by the fetal membranes (amniochorion) at the choriodecidual interface are not well established. Although immune cell migration, activation, and production of proparturition cytokines to the fetal membranes are reported, cellular level events that can generate a unique set of inflammation are not well discussed. This review discusses derangements to fetal membrane cells (physiologically and pathologically at term and preterm, respectively) in response to both endogenous and exogenous factors to generate inflammatory signals. In addition, the mechanisms of inflammatory signal propagation (fetal signaling of parturition) and how these signals cause immune imbalances at the choriodecidual interface are discussed. In addition to maternal inflammation, this review projects FIR as an additional mediator of inflammatory overload required to promote parturition. [ABSTRACT FROM AUTHOR]

Prolactin (PRL) is a pleiotropic hormone with a key role in pregnancy. In fetal membranes, PRL can regulate the secretion of pro-inflammatory factors, which induces the activation of matrix metalloproteinases (MMPs). The increase and activation of MMPs deregulate the turnover of the extracellular matrix in the fetal membranes, altering its structure and function, causing premature rupture of the membranes and preterm labor. In this work, we evaluate the effect of PRL upon the secretion of MMP-1, MMP-2, MMP-9, MMP-13, and the tissue inhibitors of metalloproteinases (TIMPs) in human fetal membranes after lipopolysaccharide (LPS) challenge. Nine fetal membranes from healthy non-laboring cesarean deliveries at term were cultured in a 2-independent chamber system and pre-treated with 250, 500, 1000 or 4000 ng/ml of PRL for 24 h, then choriodecidual region was stimulated with 500 ng/ml of LPS plus fresh PRL for 24 h. The MMPs and TIMPs secretion were quantified by ELISA, additionally MMP-2 and MMP-9 gelatinolytic activity was measured by zymography. LPS induced the MMP-9 and MMP-1 secretion, but no MMP-2 or MMP-13 in comparison with basal levels. PRL co-treatment decreased the MMP-2, MMP-9 and MMP-1 secretion induced by LPS. The active forms were present in the tissue extract, showing a response consistent with the secretion profile. TIMP-1 and TIMP-2 secretion was decreased after LPS treatment and the PRL co-treatment reverts this effect. The present results support that PRL may favor the balance between these factors involved in the structural maintenance of fetal membranes in an inflammatory event. [ABSTRACT FROM AUTHOR]

Abstract Background Human labor is associated with an inflammatory process that takes place at the maternal–fetal interface, where leukocytes infiltrate and contribute to the local production of effector molecules such as cytokines, chemokines, MMPs, etc. This process may be altered by a low‐grade chronic inflammation, characteristic of obesity, resulting in adverse pregnancy outcomes. In this cross‐sectional pilot study, we analyzed the relationship between maternal adiposity and inflammation‐related gene expression in leukocytes from six healthy women with term pregnancies without labor. Methods We estimated maternal adiposity and examined the relative expression of 211 inflammation‐related genes in maternal peripheral blood leukocytes (MAT), placental intervillous blood leukocytes (PLA), and choriodecidual leukocytes (CHD) by real‐time qPCR. Finally, we analyzed the correlation between maternal adiposity and gene expression. Results Participants’ adiposity ranged from 27.6% to 61.1% (n = 6). The expression of 23 genes significantly differed (p 0.7) mostly positively with the expression of genes related to activation, migration, infiltration, and proinflammation in MAT (36 genes) and PLA (31 genes). In contrast, in CHD leukocytes maternal adiposity correlated only negatively with seven genes, involved in migration and infiltration. Conclusion Our findings suggest that during term pregnancy, increased maternal adiposity may enhance the priming of peripheral leukocytes, while in choriodecidua it may alter leukocyte recruitment and proinflammatory activity. Maternal adiposity must be considered an important variable in further studies that analyze inflammation‐related gene expression in pregnant women.

Intra-amniotic (IA) inflammation is associated with significant morbidities for both the mother and the fetus. Prior studies have illustrated many of the effects of IA inflammation on the uterine lining (decidua) and membranous layers of the placenta at the fetal–maternal interface. However, much less is known about the immunological response occurring within the villous placenta. Using a rhesus macaque model of lipopolysaccharide (LPS)-induced IA inflammation, we showed that pregnancy-matched choriodecidua and villi have distinct immunological profiles in rhesus pregnancies. In the choriodecidua, we show that the abundance of neutrophils, multiple populations of antigen-presenting cells, and two populations of natural killer (NK) cells changes with prenatal IA LPS exposure. In contrast, in immune cells within the villous placenta we observed alterations in the abundance of B cells, monocytes, and CD8 T cells. Prior work has illustrated that IA inflammation leads to an increase in tumor necrosis factor alpha (TNFα) at the fetal–maternal interface. In this study, pretreatment with a TNFα blockade partially reversed inflammation in the placental villi. Furthermore, we report that immune cells in the villous placenta sensed LPS during our experimental window, and subsequently activated T cells to produce proinflammatory cytokines. Moreover, this study is the first report of memory T cells in third-trimester non-human primate placental villi and provides evidence that manipulation of immune cells in the villi at the fetal–maternal interface should be considered as a potential therapeutic target for IA inflammation.

Background: Human labor is associated with an inflammatory process that takes place at the maternal–fetal interface, where leukocytes infiltrate and contribute to the local production of effector molecules such as cytokines, chemokines, MMPs, etc. This process may be altered by a low‐grade chronic inflammation, characteristic of obesity, resulting in adverse pregnancy outcomes. In this cross‐sectional pilot study, we analyzed the relationship between maternal adiposity and inflammation‐related gene expression in leukocytes from six healthy women with term pregnancies without labor. Methods: We estimated maternal adiposity and examined the relative expression of 211 inflammation‐related genes in maternal peripheral blood leukocytes (MAT), placental intervillous blood leukocytes (PLA), and choriodecidual leukocytes (CHD) by real‐time qPCR. Finally, we analyzed the correlation between maternal adiposity and gene expression. Results: Participants' adiposity ranged from 27.6% to 61.1% (n = 6). The expression of 23 genes significantly differed (p < 0.05) in MAT, PLA, and CHD leukocytes, most of which code for chemokines and proinflammatory cytokines. Importantly, increasing maternal adiposity correlated (r > 0.7) mostly positively with the expression of genes related to activation, migration, infiltration, and proinflammation in MAT (36 genes) and PLA (31 genes). In contrast, in CHD leukocytes maternal adiposity correlated only negatively with seven genes, involved in migration and infiltration. Conclusion: Our findings suggest that during term pregnancy, increased maternal adiposity may enhance the priming of peripheral leukocytes, while in choriodecidua it may alter leukocyte recruitment and proinflammatory activity. Maternal adiposity must be considered an important variable in further studies that analyze inflammation‐related gene expression in pregnant women. [ABSTRACT FROM AUTHOR]

Intra-amniotic (IA) inflammation is associated with significant morbidities for both the mother and the fetus. Prior studies have illustrated many of the effects of IA inflammation on the uterine lining (decidua) and membranous layers of the placenta at the fetal–maternal interface. However, much less is known about the immunological response occurring within the villous placenta. Using a rhesus macaque model of lipopolysaccharide (LPS)-induced IA inflammation, we showed that pregnancy-matched choriodecidua and villi have distinct immunological profiles in rhesus pregnancies. In the choriodecidua, we show that the abundance of neutrophils, multiple populations of antigen-presenting cells, and two populations of natural killer (NK) cells changes with prenatal IA LPS exposure. In contrast, in immune cells within the villous placenta we observed alterations in the abundance of B cells, monocytes, and CD8 T cells. Prior work has illustrated that IA inflammation leads to an increase in tumor necrosis factor alpha (TNFα) at the fetal–maternal interface. In this study, pretreatment with a TNFα blockade partially reversed inflammation in the placental villi. Furthermore, we report that immune cells in the villous placenta sensed LPS during our experimental window, and subsequently activated T cells to produce proinflammatory cytokines. Moreover, this study is the first report of memory T cells in third-trimester non-human primate placental villi and provides evidence that manipulation of immune cells in the villi at the fetal–maternal interface should be considered as a potential therapeutic target for IA inflammation. [ABSTRACT FROM AUTHOR]

During pregnancy, the fetal membranes composed of the amnion and chorodecidua constitute a selective barrier separating two distinct environments, maternal and fetal. These tissues have the function of delimiting the amniotic cavity. Their histological complexity gives them physical, mechanical, and immunological properties to protect the fetus. Although the study of the amnion, chorion, and decidua separately provides knowledge about the functions of the fetal membranes, the protocol we describe in this chapter has the advantage of maintaining the biological and functional complexity of these tissues. In addition, this experimental model allows the researcher to recreate various pathological scenarios because this model allows for differential stimulation of the amnion or choriodecidua., (© 2024. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

During human pregnancy, leukocytes that infiltrate the maternal-fetal interface play a major role in establishing a delicate balance between immune tolerance and functional response and setting the inflammatory process that leads to labor. Here we describe two methods for isolating immune cells from the chorioamniotic membranes (decidua parietalis) and placental blood (decidua basalis) that combine gentle enzymatic digestion, magnetic cell sorting, and density gradient. Isolated leukocytes can be immunophenotypified by flow cytometry, and both isolation methods are compatible with downstream cellular and molecular applications, such as cell culture, transcriptome, and proteome analyses., (© 2024. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

Leukocyte infiltration into the maternal-fetal interface is a consequence of the robust inflammation in the gestational tissues during term labor and preterm labor with or without infection. During pregnancy, the fetal membranes act as a physical barrier that isolates the fetus into the amniotic cavity, keeping it in an optimal environment for its development. In addition, the fetal membranes possess immunological competencies such as the secretion of cytokines and chemokines in response to different stimuli. Clinical and experimental evidence indicates that these tissues are involved in the extensive chemotaxis of immune cells in normal or pathological conditions.Few studies have evaluated the chemotactic capacities of the fetal membranes considering that this tissue is composed of two adjacent tissues, the amnion and the chorion, which have different characteristics. Although these tissues function as a unit, their response is complex since there is an interaction between them, where each tissue contributes differently. The protocol described here allows us to evaluate the in vitro chemotactic capacities of fetal membranes in response to various applied stimuli, considering the contribution of each of their components (amnion and choriodecidua) using a Boyden chamber assay and phenotyping the chemo-attracted leukocytes by flow cytometry., (© 2024. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

Abstract Leukocytes found at the human maternal-fetal interface participate in the inflammatory process associated with both preterm and term labor; therein, effective methods for their isolation that allow further phenotypic and functional analyses are necessary. Leukocyte isolation is usually carried out through scraping or enzyme digestion of the choriodecidua, however both methods usually limit the use of downstream immunophenotyping or transcriptomic techniques. Here we describe an isolation method based on gentle trypsin digestion that yields a leukocyte-enriched cell mixture with high lymphocyte viability, although less viable myeloid cells. We show that the method does not compromise cell surface markers since isolated leukocytes are suitable for flow cytometry; and that high quality RNA can be obtained from these cells for qRT-PCR and microarray analyses. [ABSTRACT FROM AUTHOR]

Trisomy 21 (T21) is the most common chromosome abnormality in humans and is associated with a spectrum of phenotypes, including cognitive impairment, congenital heart defects and immune system defects. In addition, T21 is also associated with abnormalities of fetal membranes including chorioamniotic separation, delayed fusion of the chorioamniotic membranes, defects in syncytiotrophoblast formation, as well as amniocyte senescence. There is evidence indicating miRNAs encoded by sequences on chromosome 21 (Chr-21) are involved in several of the cognitive and neurological phenotypes of T21, but the role of Chr-21 derived miRNAs in fetal membrane abnormalities associated with T21 has not been investigated. In the current study, we determined the expression patterns of three miRNAs derived from a cluster on Chr-21 - hsa-miR-99a, hsa-miR-125b and hsa-let-7c in chorioamniotic membranes obtained from term pregnancies with spontaneous rupture (n = 20). Tissue and location specific expression patterns within the chorioamniotic membranes were identified. The rupture zone in the choriodecidua had distinct expression patterns compared to other fetal membrane locations. Despite the increased gene dosage associated with T21, the expression of all three miRNAs was reduced in cultured T21 amniocytes as compared to cultured euploid amniocytes. In silico analysis of experimentally validated targets of the three miRNAs suggest these Chr-21 derived miRNAs play a potential role in fetal membrane rupture and the fetal membrane defects associated with T21. [ABSTRACT FROM AUTHOR]

Rupture of the fetal membranes (FM) is precipitated by stretch forces acting upon biochemically mediated, pre-weakened tissue. Term FM develop a para-cervical weak zone, characterized by collagen remodeling and apoptosis, within which FM rupture is thought to initiate. Preterm FM also have a weak region but are stronger overall than term FM. Inflammation/infection and decidual bleeding/abruption are strongly associated with preterm premature FM rupture (pPROM), but the specific mechanisms causing FM weakening-rupture in pPROM are unknown. There are no animal models for study of FM weakening and rupture. Over a decade ago we developed equipment and methodology to test human FM strength and incorporated it into a FM explant system to create an in-vitro human FM weakening model system. Within this model TNF (modeling inflammation) and Thrombin (modeling bleeding) both weaken human FM with concomitant up regulation of MMP9 and cellular apoptosis, mimicking the characteristics of the spontaneous FM rupture site. The model has been enhanced so that test agents can be applied directionally to the choriodecidual side of the FM explant consistent with the in-vivo situation. With this enhanced system we have demonstrated that the pathways involving inflammation/TNF and bleeding/Thrombin induced FM weakening overlap. Furthermore GM-CSF production was demonstrated to be a critical common intermediate step in both the TNF and the Thrombin induced FM weakening pathways. This model system has also been used to test potential inhibitors of FM weakening and therefore pPROM. The dietary supplement α-lipoic acid and progestogens (P4, MPA and 17α-hydroxyprogesterone) have been shown to inhibit both TNF and Thrombin induced FM weakening. The progestogens act at multiple points by inhibiting both GM-CSF production and GM-CSF action. The use of a combined biomechanical/biochemical in-vitro human FM weakening model system has allowed the pathways of fetal membrane weakening to be delineated, and agents that may be of clinical use in inhibiting these pathways to be tested. [ABSTRACT FROM AUTHOR]

Problem Inflammation is a driver of labor in myometrium and cervix; however, the involvement of decidua is poorly defined. We have reported decidual leukocyte infiltration prior to and during labor; the regulators of these inflammatory processes are unknown. Method of study Choriodecidua RNA obtained after term labor or elective cesarean delivery was applied to Affymetrix GeneChips. Pathway analysis and gene validation were performed. Results Extensive inflammatory activation was identified in choriodecidua following labor, predominantly upregulation of genes regulating leukocyte trafficking and cytokine signalling. Genes governing cell fate, tissue remodelling, and translation were also altered. Upregulation of candidate genes ( ICAM1, CXCR4, CD44, TLR4, SOCS3, BCL2A, and IDO) was confirmed. NFκB, STAT1&3, HMGB1, and mi RNA-21, mi RNA-46, mi RNA-141, and mi RNA-200 were predicted upstream regulators. Conclusion This study confirms inflammatory processes are major players in labor events in choriodecidua, as in other gestational tissues. Suppressing uterine inflammation is likely to be critical for arresting premature labor. [ABSTRACT FROM AUTHOR]

Problem Human parturition is associated with an intrauterine pro-inflammatory environment in the choriodecidua. Evidence that some mediators of this signaling cascade also elicit responses leading to labor prompted us to characterize the cellular sources of these mediators in the human choriodecidua. Method of study Leukocyte-enriched preparations from human choriodecidua ( Ch L) and intervillous placental blood leukocytes ( PL) were maintained in culture. Secretions of inflammatory cytokines, chemokines, and MMP-9 were documented. Leukocyte phenotype of Ch L and PL was determined by flow cytometry using specific fluorochrome-conjugated antibodies. Results and Conclusions Ch L showed a distinct pro-inflammatory secretion pattern of cytokines and chemokines when compared with PL, including higher amounts of TNF-α and IL-6, and decreased secretions of IL-4 and IL-1ra. Ch L also secreted more MIP-1α and MCP-1 and MMP-9 than PL. No significant differences were found in leukocytes subsets between compartments. Based on our findings, we propose that Ch L isolated from fetal membranes at term are functionally different from PL and may collaborate to modulate the microenvironment linked to induction and progression of human labor. [ABSTRACT FROM AUTHOR]

Abstract: Introduction: Labour and delivery are processes associated with inflammation within intrauterine and cervical tissues. The mechanisms that induce labour-associated changes and, in particular, the role of microRNAs (miRNAs) remain to be elucidated. MiRNAs are small non-coding RNAs that repress gene expression via mRNA degradation and translational repression. Let-7 miRNAs are negatively regulated by RNA-binding protein, Lin28, and both function downstream of NF-κB signalling. In non-gestational tissues, let-7 and Lin28 reportedy function as negative and positive regulators of IL-6 expression. We hypothesised that labour-associated inflammation involves the downregulation of let-7 miRNAs and upregulation of Lin28 expression. Aim: To determine the expression of Lin28 protein and let-7 miRNA in human gestational tissue obtained before and after labour. Method: Gestational tissues were collected from women at term by Caesarean section with and without labour and following normal vaginal delivery (n = 6 per group). Protein and RNA was extracted and Lin28 and let-7 miRNA expression was measured by Western blotting and real-time PCR. Results: The data obtained established that let-7 miRNA and Lin28 display tissue-specific expression: Lin28 was strongly expressed in the placenta and choriodecidua, but not measurable in amnion; and let-7b and -7c expression were significantly lower in choriodecidua compare to placenta and amnion, whereas the amnion expressed less let-7d and -7f than other tissues. Conclusion: While the expression of Lin28 protein and let-7 miRNA did not vary significantly with labour onset and delivery, changes in their bioactivity and impact on nuclear signalling pathways in human gestational tissues remain to be established. [Copyright &y& Elsevier]

Problem Spontaneous labor at term involves leukocyte recruitment and infiltration into the choriodecidua; yet, characterization of these leukocytes and their immunological mediators is incomplete. The purpose of this study was to characterize the immunophenotype of choriodecidual leukocytes as well as the expression of inflammatory mediators in human spontaneous parturition at term. Method of study Choriodecidual leukocytes were analyzed by FACS, immunohistochemistry, and RT- PCR in three different groups: (i) preterm gestation delivered for medical indications without labor; (ii) term pregnancy without labor; and (iii) term pregnancy after spontaneous labor. Results Two T-cell subsets of memory-like T cells ( CD3+ CD4+ CD45 RO+ and CD3+ CD4− CD8− CD45 RO+ cells) were identified in the choriodecidua of women who had spontaneous labor. Evidence for an extensive immune signaling network composed of chemokines ( CXCL8 and CXCL10), chemokine receptors ( CXCR1-3), cytokines ( IL-1β and TNF-α), cell adhesion molecules, and MMP-9 was identified in these cells during spontaneous labor at term. Conclusions The influx of memory-like T cells in the choriodecidua and the evidence that they are active by producing chemokines and cytokines, and expressing chemokine receptors, cell adhesion molecules, and a matrix-degrading enzyme provides support for the participation of the adaptive immune system in the mechanisms of spontaneous parturition at term. [ABSTRACT FROM AUTHOR]

Abstract: Intrauterine infection frequently leads to preterm birth (PTB), with the pathophysiology involving activation of the innate immune system and its associated inflammatory response. The choriodecidua produces relaxin (RLN) and elevated levels are associated with preterm premature rupture of the fetal membranes. However, it is not increased in bacterially-mediated PTB, but may act as an endogenous sterile inflammatory mediator. Elevated systemic RLN levels from the corpus luteum are also associated with PTB, but the mechanism is unknown. In clinical obstetrics, intrauterine inflammation or infection can coexist with elevated RLN. Therefore, in this study, we further characterized the effects of RLN alone or together with an inflammatory mediator on the production of IL1B, CSF2 (GM-CSF), IL6, IL8 and TNF, from chorionic cytotrophoblasts (CyT), decidual fibroblasts (DF) and stromal cells (DSC), using interleukin-1 beta (IL1B) to mimic sterile inflammation or lipopolysaccharide (LPS) for bacterial infection. Endogenous differences between the cells showed that the CyT expressed more RLN, its receptor RXFP1 and the RXFP1 splice variant D. CyT also showed the most robust cAMP response to RLN with increased IL6 secreted after 4 h, preceded by increased transcription at 1 h, likely due to activation of RXFP1 and cAMP. When all cell types were treated with IL1B and RLN, RLN augmented secretion of IL6 and IL8 from CyT and DF, but not DSC. Similarly, RLN augmented LPS-induced IL6 secretion from CyT and DF. Despite the structural similarity between TLR4 and RXFP1, blocking TLR4 in CyT had no effect on RLN-induced IL6 secretion, suggesting specific activation of RXFP1. Thus, we have shown that in the presence of a low level of intrauterine inflammation/infection, elevated RLN could act on the CyT and DF to augment the inflammatory response, contributing to the pathophysiology of PTB. Summary: RLN augments the inflammatory responses induced by IL1B or LPS in chorionic cytotrophoblasts and decidual fibroblasts. [Copyright &y& Elsevier]

Because relevant biochemical changes are known to begin at the choriodecidual interface some weeks before actual clinical onset of labor, we hypothesized that the preterm choriodecidua may display gene and protein expression patterns specific to preterm labor. Transcriptomic (microarray) and proteomic (2-dimensional gel electrophoresis [2DGE]) profiling methodologies were used to compare changes in choriodecidual tissue collected from women who delivered before 35 weeks of gestation following spontaneous preterm labor (n = 12) and gestation-matched nonlaboring controls (n = 7). Additionally, 2DGE was used to compare differences in protein expression during term and preterm labor and to construct a choriodecidual proteome map. Overall, expressed transcripts and proteins indicated active tissue remodeling independent of labor status and an association with inflammatory processes during labor. Spontaneous, infection-induced and abruption-associated preterm deliveries were each defined by distinct transcriptional profiles. Proteins osteoglycin and progesterone receptor component 2 (PGRMC2) were upregulated during term and preterm labor while galectin 1, annexin 3, annexin 5, and protein disulfide isomerase (PDI) were upregulated only during preterm labor, suggesting a probable association with the underlying pathology. Together, these results represent novel data that warrant further investigations to elucidate plausible causal relationships of these molecules with spontaneous preterm delivery. [ABSTRACT FROM AUTHOR]

Abstract: Introduction: The fetal membrane (FM) layers, amnion and choriodecidua, are frequently noted to have varying degrees of separation following delivery. FM layers normally separate prior to rupture during in vitro biomechanical testing. We hypothesized that the adherence between amnion and choriodecidua decreases prior to delivery resulting in separation of the FM layers and facilitating FM rupture. Methods: FM from 232 consecutively delivered patients were examined to determine the extent of spontaneous separation of the FM layers at delivery. Percent separation was determined by the weight of separated FM tissue divided by the total FM weight. Separately, the adherence between intact FM layers was determined. FM adherence was tested following term vaginal delivery (13), term unlabored cesarean section (10), and preterm delivery (6). Results: Subjects enrolled in the two studies had similar demographic and clinical characteristics. FM separation was present in 92.1% of membranes. Only 4.3% of FM delivered following spontaneous rupture of the fetal membranes (SROM) had no detectable separation. 64.7% of FM had greater than 10% separation. FM from term vaginal deliveries had significantly more separation and were less adherent than FM of term unlabored, elective cesarean section (39.0±34.4% vs 22.5±30.9%, p=.046 and 0.041±0.018N/cm vs 0.048±0.019N/cm, p<.005). Preterm FM had less separation and were more adherent than term FM (9.95±17.7% vs 37.5±34.4% and 0.070±0.040N/cm vs 0.044±0.020N/cm; both p<.001). Conclusions: Separation of the amnion from choriodecidua at delivery is almost universal. Increased separation is associated with decreased adherence as measured in vitro. Increased separation and decreased adherence are seen both with increasing gestation and with labor suggesting both biochemical and mechanical etiologies. The data are consistent with the hypothesis that FM layer separation is part of the FM weakening process during normal parturition. [Copyright &y& Elsevier]

Abstract: Chorioamnionitis is implicated in the pathogenesis of preterm delivery. However, the detailed mechanisms by which infection induces preterm labor are not well understood. This study has assessed the involvement of mitogen-activated protein (MAP) kinases in lipopolysaccharide (LPS)-induced pro- and anti-inflammatory cytokine and prostaglandin (PG) production in human choriodecidua. Samples of choriodecidua were collected before the onset of labor from women undergoing elective cesarean sections at term for breech presentation, previous cesarean delivery or cephalopelvic disproportion. Concentrations of TNFα, IL-10, PGE2 and PGF2α in culture supernatants were measured by ELISA. Expression of COX-2 protein was analyzed by Western blotting. In human choriodecidual explants, LPS induced TNFα and IL-10 production in a dose- and time-dependent manner. LPS also up-regulated COX-2 expression and PG synthesis. Phosphorylations of extracellular signal-regulated kinase (ERK) 1/2, p38 MAPK, and c-Jun N-terminal kinases (JNK) were also confirmed by Western blotting. Furthermore, the effect of MAPK inhibitors was examined on LPS-induced pro- and anti-inflammatory cytokines and PG synthesis. Among the MAPK inhibitors examined, the p38 MAPK inhibitor, SB202190, significantly suppressed LPS-induced cytokine and PG production. SB202190 most profoundly suppressed the TNFα to IL-10 ratio, demonstrating that p38 MAPK inhibitor reduced predominantly TNFα other than IL-10 production. Phospho-p38 MAPK immunostaining was intense in extravillous trophoblast cells. The p38 MAPK seems to be most involved in signaling mechanisms when infection and inflammation cause preterm labor through PG synthesis. Novel therapeutic modalities targeting p38 MAPK may prevent to arrest preterm labor. [Copyright &y& Elsevier]

Objective: This study was undertaken to determine the sequence of events that occur during fetal membrane (FM) rupture and to compare the biophysical properties of intact FM with its separated individual components (amnion and choriodecidua). Study design: FM physical properties were determined with computerized, specially adapted, industrial, strength testing equipment and the rupture sequence (in vitro) video documented. Separated individual FM component properties were compared with those of reapproximated components, and of intact FMs. Results: The sequence of FM rupture was (1) FM components stretch together under load; (2) amnion separates from choriodecidua; (3) choriodecidua ruptures: (4) amnion distends further, nonelastically; and (5) amnion ruptures. In all FMs tested, amnion was stronger, stiffer, and more ductile than choriodecidua. The sum of work required to rupture separated FM components (amnion + choriodecidua), or reapproximated components, was significantly less than that of intact FMs. Conclusion: Separation of amnion from choriodecidua occurs as part of normal term FM rupture. FMs become significantly weaker as a result of this separation. [ABSTRACT FROM AUTHOR]

Objective: Uterine overdistention is thought to induce preterm labor in women with twin and multiple pregnancies, but the pathophysiology remains unclear. We investigated for the first time the pathogenesis of preterm birth associated with rapid uterine distention in a pregnant nonhuman primate model.Study Design: A nonhuman primate model of uterine overdistention was created using preterm chronically catheterized pregnant pigtail macaques (Macaca nemestrina) by inflation of intraamniotic balloons (N = 6), which were compared to saline controls (N = 5). Cesarean delivery was performed due to preterm labor or at experimental end. Microarray, quantitative reverse transcriptase polymerase chain reaction, Luminex (Austin, TX), and enzyme-linked immunosorbent assay were used to measure messenger RNA (mRNA) and/or protein levels from monkey (amniotic fluid, myometrium, maternal plasma) and human (amniocytes, amnion, myometrium) tissues. Statistical analysis employed analysis of covariance and Wilcoxon rank sum. Biomechanical forces were calculated using the law of Laplace.Results: Preterm labor occurred in 3 of 6 animals after balloon inflation and correlated with greater balloon volume and uterine wall stress. Significant elevations of inflammatory cytokines and prostaglandins occurred following uterine overdistention in an "inflammatory pulse" that correlated with preterm labor (interleukin [IL]-1β, tumor necrosis factor [TNF]-α, IL-6, IL-8, CCL2, prostaglandin E2, prostaglandin F2α, all P < .05). A similar inflammatory response was observed in amniocytes in vitro following mechanical stretch (IL1β, IL6, and IL8 mRNA multiple time points, P < .05), in amnion of women with polyhydramnios (IL6 and TNF mRNA, P < .05) and in amnion (TNF-α) and myometrium of women with twins in early labor (IL6, IL8, CCL2, all P < .05). Genes differentially expressed in the nonhuman primate after balloon inflation and in women with polyhydramnios and twins are involved in tissue remodeling and muscle growth.Conclusion: Uterine overdistention by inflation of an intraamniotic balloon is associated with an inflammatory pulse that precedes and correlates with preterm labor. Our results indicate that inflammation is an early event after a mechanical stress on the uterus and leads to preterm labor when the stress is sufficiently great. Further, we find evidence of uterine tissue remodeling and muscle growth as a common, perhaps compensatory, response to uterine distension. [ABSTRACT FROM AUTHOR]

Objective: The purpose of this study was to compare the chemotactic activity of the choriodecidua and amnion, and to identify the phenotype of the leukocytes chemoattracted by each tissue. Study Design: Amnion, choriodecidua and whole fetal membranes extracts were obtained from women at term (>37 weeks of gestation) with or without labor (n = 5 each). Extracts were assayed for leukocyte chemotactic activity, and the number and phenotype of the chemoattracted leukocytes were characterized by flow cytometry. Results: Although all of the extracts exhibited chemotactic activity, more leukocytes were chemoattracted by the choriodecidua and the whole fetal membranes during labor compared with no labor (P = .010, .008). During labor the choriodecidua is responsible for granulocyte, T-lymphocyte, monocyte, and natural killer-cell chemoattraction, and the amnion is responsible for B-lymphocyte chemoattraction. Conclusion: Choriodecidua and amnion exhibit chemotactic activity for selective leukocytes and thus, each fetal membrane differentially regulates leukocyte chemotactic activity during labor. [ABSTRACT FROM AUTHOR]