Changes in the expression of the type-2 but not the type-1 cyclo-oxygenase enzyme in chorion-decidua with the onset of labour

Preterm labor with and without chorioamnionitis is associated with activation of myometrial inflammatory networks: a comprehensive transcriptomic analysis

BACKGROUND

The onset of preterm labor is associated with inflammation. Previous studies suggested that this is distinct from the inflammation observed during term labor. Our previous work on 44 genes differentially expressed in myometria in term labor demonstrated a different pattern of gene expression from that observed in preterm laboring and nonlaboring myometria. We found increased expression of inflammatory genes in preterm labor associated with chorioamnionitis, but in the absence of chorioamnionitis observed no difference in gene expression in preterm myometria regardless of laboring status, suggesting that preterm labor is associated with different myometrial genes or signals originating from outside the myometrium. Given that a small subset of genes were assessed, this study aimed to use RNA sequencing and bioinformatics to assess the myometrial transcriptome during preterm labor in the presence and absence of chorioamnionitis.

OBJECTIVE

This study aimed to comprehensively determine protein-coding transcriptomic differences between preterm nonlaboring and preterm laboring myometria with and without chorioamnionitis.

STUDY DESIGN

Myometria were collected at cesarean delivery from preterm patients not in labor (n=16) and preterm patients in labor with chorioamnionitis (n=8) or without chorioamnionitis (n=6). Extracted RNA from myometrial tissue was prepared and sequenced using Illumina NovaSeq. Gene expression was quantified by mapping the sequence reads to the human reference genome (hg38). Differential gene expression analysis, gene set enrichment analysis, and weighted gene coexpression network analysis were used to comprehensively interrogate transcriptomic differences and their associated biology.

RESULTS

Differential gene expression analysis comparing preterm patients in labor with chorioamnionitis with preterm patients not in labor identified 931 differentially expressed genes, whereas comparing preterm patients in labor without chorioamnionitis with preterm patients not in labor identified no statistically significant gene expression changes. In contrast, gene set enrichment analysis and weighted gene coexpression network analysis demonstrated that preterm labor with and without chorioamnionitis was associated with enrichment of pathways involved in activation of the innate immune system and inflammation, and activation of G protein-coupled receptors. Key genes identified included chemotactic CYP4F3, CXCL8, DOCK2, and IRF1 in preterm labor with chorioamnionitis and CYP4F3, FCAR, CHUK, and IL13RA2 in preterm labor without chorioamnionitis. There was marked overlap in the pathways enriched in both preterm labor subtypes.

CONCLUSION

Differential gene expression analysis demonstrated that myometria from preterm patients in labor without chorioamnionitis and preterm patients not in labor were transcriptionally similar, whereas the presence of chorioamnionitis was associated with marked gene changes. In contrast, comprehensive bioinformatic analysis indicated that preterm labor with or without chorioamnionitis was associated with innate immune activation. All causes of preterm labor were associated with activation of the innate immune system, but this was more marked in the presence of chorioamnionitis. These data suggest that anti-inflammatory therapy may be relevant in managing preterm labor of all etiologies.

Different Chemical Structures and Physiological/Pathological Roles of Cyclooxygenases

This review describes cyclooxygenase (COX), which synthesizes prostanoids that play an important role in living things. The authors conducted a national and international literature review on the subject. The COX enzyme uses arachidonic acid to form prostanoids, which play a role in several physiological and pathological conditions. This enzyme has different isoforms, mainly COX-1 and COX-2. The constitutive isoform is COX-1, while COX-2 is the inducible isoform. Both are expressed in different tissues and at different levels, but they may also coexist within the same tissue. Both isoforms show essentially the same mode of action, but their substrates and inhibitors may differ. The COX-1 isoform, which plays a role in the continuation of physiological events, has an increased expression level in various carcinomas, and the COX-2 isoform, which is increased in inflammatory conditions, is typically expressed at low physiological levels in some tissues such as the brain, kidney, and uterus. In addition to investigating the efficacies of the COX-1 and COX-2 isoforms, the discovery of potential new COX enzymes and their effect continues. This review also looks at the roles of the COX enzyme in certain physiological and pathological conditions.

PGE2 vs PGF2α in human parturition

Prostaglandin E2 (PGE2) and F2α (PGF2α) are the two most prominent prostanoids in parturition. They are involved in cervical ripening, membrane rupture, myometrial contraction and inflammation in gestational tissues. Because multiple receptor subtypes for PGE2 and PGF2α exist, coupled with diverse signaling pathways, the effects of PGE2 and PGF2α depend largely on the spatial and temporal expression of these receptors in intrauterine tissues. It appears that PGE2 and PGF2α play different roles in parturition. PGE2 is probably more important for labor onset, while PGF2α may play a more important role in labor accomplishment, which may be attributed to the differential effects of PGE2 and PGF2α in gestational tissues. PGE2 is more powerful than PGF2α in the induction of cervical ripening. In terms of myometrial contraction, PGE2 produces a biphasic effect with an initial contraction and a following relaxation, while PGF2α consistently stimulates myometrial contraction. In the fetal membranes, both PGE2 and PGF2α appear to be involved in the process of membrane rupture. In addition, PGE2 and PGF2α may also participate in the inflammatory process of intrauterine tissues at parturition by stimulating not only neutrophil influx and cytokine production but also cyclooxygenase-2 expression thereby intensifying their own production. This review summarizes the differential roles of PGE2 and PGF2α in parturition with respect to their production and expression of receptor subtypes in gestational tissues. Dissecting the specific mechanisms underlying the effects of PGE2 and PGF2α in parturition may assist in developing specific therapeutic targets for preterm and post-term birth.

Cyclooxygenase inhibitors for treating preterm labour: What is the molecular evidence? 1

Preterm birth (<37 weeks of gestation) significantly increases the risk of neonatal mortality and morbidity. As many as half of all preterm births occur following spontaneous preterm labour. Since in such cases there are no known reasons for the initiation of labour, treatment of preterm labour (tocolysis) has sought to stop labour contractions and delay delivery. Despite some success, the use of cyclooxygenase (COX) inhibitors is associated with maternal/fetal side effects, and possibly increased risk of preterm birth. Clinical use of these drugs predates the collection of molecular and biochemical evidence in vitro, examining the expression and activity of COX enzymes in pregnant uterine tissues with and without labour. Such evidence is important to the rationale that COX enzymes are, or are not, appropriate targets for the tocolysis. The current study systematically searched existing scientific evidence to address the hypothesis that COX expression/activity is increased with the onset of human labour, in an effort to determine whether there is a rationale for the use of COX inhibitors as tocolytics. Our review identified 44 studies, but determined that there is insufficient evidence to support or refute a role of COX-1/-2 in the onset of preterm labour that supports COX-targeted tocolysis.

Identification of SMAD3 as a Novel Mediator of Inflammation in Human Myometrium In Vitro

Preterm birth remains the primary cause of early neonatal death and is a major determinant for long-term health consequences. Aberrant intrauterine inflammation and infection are known to augment the synthesis of proinflammatory cytokines and induce uterine contractions, which can subsequently lead to preterm birth. The transforming growth factor-β (TGF-β) superfamily members regulate numerous cellular processes through the activation of intracellular mediators known as mothers against decapentaplegic homolog (SMADs). Studies in nongestational tissues have shown that SMAD3 plays a role in immune regulation and inflammation; however, its role in human labour remains unknown. Thus, the present study aimed at (i) characterising the expression of SMAD3 in the human myometrium; (ii) determining the effect of bacterial and viral products and proinflammatory cytokines on SMAD3 transcriptional activity in primary human myometrial cells; and (iii) investigating the effect of SMAD3 siRNA knockdown on the production of prolabour mediators in primary human myometrial cells. Phosphorylated (i.e., active) SMAD3 protein expression was lower in the myometrium after spontaneous term labour compared to the myometrium from nonlabouring women. Using a luciferase assay, the proinflammatory cytokines IL-1β and TNF, and viral analogue polyinosinic : polycytidylic acid (poly(I : C)) significantly reduced SMAD3 transcriptional activity in human primary myometrial cells. Loss-of-function studies found that SMAD3 knockdown in myometrial cells significantly increased IL-1β- and poly(I : C)-induced proinflammatory cytokines (IL-1A, IL-6), chemokines (IL-8, MCP-1), the adhesion molecule ICAM-1, COX-2 mRNA expression, and subsequent PGF2α release. In conclusion, SMAD3 deficiency is associated with increased production of proinflammatory and prolabour mediators in the human myometrium.

Preterm labor in the absence of acute histologic chorioamnionitis is characterized by cellular senescence of the chorioamniotic membranes

BACKGROUND

Decidual senescence has been considered a mechanism of disease for spontaneous preterm labor in the absence of severe acute inflammation. Yet, signs of cellular senescence have also been observed in the chorioamniotic membranes from women who underwent the physiological process of labor at term.

OBJECTIVE

We aimed to investigate whether, in the absence of acute histologic chorioamnionitis, the chorioamniotic membranes from women who underwent spontaneous preterm labor or labor at term exhibit signs of cellular senescence.

STUDY DESIGN

Chorioamniotic membrane samples were collected from women who underwent spontaneous preterm labor or labor at term. Gestational age-matched nonlabor controls were also included. Senescence-associated genes/proteins were determined using reverse transcription quantitative polymerase chain reaction analysis (n = 7-9 each for array; n = 26-28 each for validation), enzyme-linked immunosorbent assays (n = 7-9 each), immunoblotting (n = 6-7 each), and immunohistochemistry (n = 7-8 each). Senescence-associated β-galactosidase activity (n = 7-11 each) and telomere length (n = 15-22 each) were also evaluated.

RESULTS

In the chorioamniotic membranes without acute histologic chorioamnionitis: (1) the expression profile of senescence-associated genes was different between the labor groups (term in labor and preterm in labor) and the nonlabor groups (term no labor and preterm no labor), yet there were differences between the term in labor and preterm in labor groups; (2) most of the differentially expressed genes among the groups were closely related to the tumor suppressor protein (TP53) pathway; (3) the expression of TP53 was down-regulated in the term in labor and preterm in labor groups compared to their nonlabor counterparts; (4) the expression of CDKN1A (gene coding for p21) was up-regulated in the term in labor and preterm in labor groups compared to their nonlabor counterparts; (5) the expression of the cyclin kinase CDK2 and cyclins CCNA2, CCNB1, and CCNE1 was down-regulated in the preterm in labor group compared to the preterm no labor group; (6) the concentration of TP53 was lower in the preterm in labor group than in the preterm no labor and term in labor groups; (7) the senescence-associated β-galactosidase activity was greater in the preterm in labor group than in the preterm no labor and term in labor groups; (8) the concentration of phospho-S6 ribosomal protein was reduced in the term in labor group compared to its nonlabor counterpart, but no differences were observed between the preterm in labor and preterm no labor groups; and (9) no significant differences were observed in relative telomere length among the study groups (term no labor, term in labor, preterm no labor, and preterm in labor).

CONCLUSION

In the absence of acute histologic chorioamnionitis, signs of cellular senescence are present in the chorioamniotic membranes from women who underwent spontaneous preterm labor compared to those who delivered preterm in the absence of labor. However, the chorioamniotic membranes from women who underwent spontaneous labor at term did not show consistent signs of cellular senescence in the absence of histologic chorioamnionitis. These results suggest that different pathways are implicated in the pathological and physiological processes of labor.

Gestational tissue inflammatory biomarkers at term labor: A systematic review of literature

Parturition at term is characterized by inflammatory overload in both feto-maternal tissues. Despite the large number of individual studies on changes in inflammatory biomarkers linked to labor, a comprehensive profile of them in each of the uterine compartments is not available to better understand their mechanistic contributions to labor. This systematic review investigated the pro- and anti-inflammatory biomarkers reported in intra-uterine tissues (amnion, chorion, decidua, placenta, and myometrium) at term labor. We conducted a systematic review of studies on pro- and anti-inflammatory biomarkers (mRNA and/or protein) reported in feto-maternal tissues during normal human term labor, published in English (1980-2016), in 3 electronic data bases. From a total of 3712 citations, 172 were included for final review. Each tissue expresses a unique set of biomarkers at the time of term labor, but there is significant overlap between tissues. All tissues had IL-6, IL-8, IL-1β, COX-2, PGE-2, TNF-α, and hCAP18 in common at term labor. Common and unique inflammatory biomarkers are expressed in various feto-maternal compartments at term labor. Increase in pro-inflammatory markers in all gestational tissue signifies their harmonious functional role in promoting labor. Anti-inflammatory markers at term labor are hardly reported.

Leukocyte Density and Proinflammatory Mediator Expression in Regional Human Fetal Membranes and Decidua Before and During Labot at Term

OBJECTIVES

The region of fetal membranes overlying the cervix, known as the zone of altered morphology (ZAM), is considered to be the principle site of membrane inflammatory activity and extracellular matrix remodelling. We wished to quantify the relative contribution of each area of fetal membranes to the inflammatory process of parturition. Specifically, we aimed to quantify and compare (1) leukocyte densities in three regions of fetal membranes and decidua before and during spontaneous labor at term, and (2) mRNA expression of interleukin (IL)-1beta, IL-6, IL-8, cyclo-oxygenase type 1 (COX-1), and COX-2 in three regions of fetal membranes and decidua before and during spontaneous labor at term.

METHODS

Biopsies of fetal membranes and decidua were obtained from pregnant women delivered by cesarean section at term both before and during spontaneous labor (n = 8 both groups). Fetal membranes were sampled from three areas, the ZAM, midzone (MZ), and periplacental (PP) regions. Leukocytes were identified by immunohistochemistry and their density quantified. Inflammatory mediator expression was quantified using TaqMan technology (Applied Biosystems, Foster City, CA).

RESULTS

There was a significantly greater density of leukocytes in (1) the PP region of membranes compared with the ZAM, and (2) the decidua compared with amnion, amniotic connective tissue, and chorion. IL-1beta, IL-6, and IL-8 mRNA expression was significantly greater in all regions following spontaneous labor compared with nonlaboring tissues. There were no regional differences in cytokine expression within the fetal membranes. Choriodecidua expressed significantly more IL-1beta mRNA than amnion. Amnion expressed more COX-2 mRNA than choriodecidua.

CONCLUSIONS

All regions of fetal membranes and decidua contribute to the inflammatory process of human parturition; however, their relative contributions differ in magnitude. Although the ZAM may be specifically important for membrane rupture, it does not appear to play a key or exclusive role in the other inflammatory processes of parturition. When studying fetal membranes, it is relevant to identify and define the area sampled for consistency and comparison with other studies.

Prostaglandin pathway gene expression in human placenta, amnion and choriodecidua is differentially affected by preterm and term labour and by uterine inflammation

Background

Elucidation of the biochemical pathways involved in activation of preterm and term human labour would facilitate the development of effective management and inform judgements regarding the necessity for preterm tocolysis and post-term induction. Prostaglandins act at all stages of human reproduction, and are potentially activators of labour.

Methods

Expression of 15 genes involved in prostaglandin synthesis, transport and degradation was measured by qPCR using tissue samples from human placenta, amnion and choriodecidua at preterm and full-term vaginal and caesarean delivery. Cellular localisation of eight prostaglandin pathway proteins was determined by immunohistochemistry.

Results

Expression of prostaglandin pathway genes was differentially affected by factors including gestational age at delivery, and the incidence and duration of labour. Chorioamnionitis/deciduitis was associated with upregulation of PTGS2 (prostaglandin-endoperoxide synthase 2 (prostaglandin G/H synthase and cyclooxygenase)), along with the inflammatory genes IL8 (interleukin 8), S100A8 (S100 calcium binding protein A8) and TLR2 (toll-like receptor 2), in amnion and choriodecidua, and with downregulation of CBR1 (carbonyl reductase 1) and HPGD (hydroxyprostaglandin dehydrogenase 15-(NAD)) in choriodecidua. Protein localisation differed greatly between the various maternal and fetal cell types.

Conclusions

Preterm and term labour are associated with distinct prostaglandin pathway expression profiles; inflammation provokes specific changes, unrelated to the presence of labour; spontaneous and induced term labour are indistinguishable.

Labor and inflammation increase the expression of oxytocin receptor in human amnion

The oxytocin/oxytocin receptor (OXT/OXTR) system plays an important role in the regulation of parturition. The amnion is a major source of prostaglandins and inflammatory cytokine synthesis, which increase both before and during labor. Amnion is a noncontractile tissue; therefore, the role played by OXT/OXTR in this tissue will be fundamentally different from the role played in myometrial contractions. In the present study, we demonstrate increased OXTR mRNA and protein concentrations in human amnion epithelial cells associated with the onset of labor. We show that incubation of primary human amnion epithelial cells with IL1B results in a rapid, transient up-regulation of OXTR mRNA expression, which peaks in prelabor samples after 6 h. Incubation of prelabor amnion epithelial cells with OXT results in a marked increase of prostaglandin E(2) synthesis, and we demonstrate that OXT activates the extracellular signal-regulated protein kinase signal transduction pathway to stimulate up-regulation of cyclo-oxygenase 2 in human amnion epithelial cells. The increased ability of human amnion to produce prostaglandins in response to OXT treatment suggests a complementary role for the OXT/OXTR system in the activation of human amnion and the onset of labor.

Evidence for a spatial and temporal regulation of prostaglandin-endoperoxide synthase 2 expression in human amnion in term and preterm parturition

CONTEXT

Prostaglandin-endoperoxide synthase 2 (PTGS2) is a key enzyme involved in parturition. PTGS2 mRNA was found to be differentially expressed between placental amnion (amnion overlying the placental disc) and reflected amnion (amnion of the extraplacental chorioamniotic membranes) in term placentas.

OBJECTIVE

The aim was to evaluate the spatial and temporal regulation of PTGS2 expression in the amnion and the chorion-decidua.

DESIGN

PTGS2 expression was analyzed in the amnion and chorion-decidua obtained from 32 women: term not in labor (n = 12), term in labor (n = 12), and preterm labor (n = 8), by immunoblotting and densitometry. Prostaglandin E(2) (PGE(2)) in the amnion and chorion-decidua was measured by a specific immunoassay.

RESULTS

Compared to preterm labor cases, PTGS2 expression increased at term before the onset of labor far more prominently in placental amnion (4.5-fold; P = 0.002) than in reflected amnion (1.4-fold; P = 0.007). There was a significant increase in PTGS2 expression in reflected amnion (2.9-fold; P < 0.01) but not in placental amnion with labor at term. PTGS2 expression was higher in reflected amnion than in chorion-decidua in labor at term (2.9-fold; P < 0.01). PTGS2 was barely detected in amnion and chorion-decidua with preterm labor. Expression of PGE(2) showed a good correlation with PTGS2 expression (r = 0.722; P < 0.001).

CONCLUSION

PTGS2 expression in the amnion shows a distinct spatial and temporal regulation. Spontaneous labor at term and pathological preterm labor clearly differ in amniotic PTGS2 and PGE(2) abundance. Our observations underscore the biological significance of the amnion and amniotic fluid in human parturition.

Role of Non-Steroidal Anti-Inflammatory Drugs in Gynecology

This review summarizes the current use of non-steroidal anti-inflammatory drugs (NSAIDs) in obstetrics, gynecology and infertility. These medications are commonly used in different fields of reproductive medicine, for pain management after operative procedures and to relieve dysmenorrhea. In addition to their analgesic effect, NSAIDs are helpful in the management of menorrhagia by decreasing menstrual blood loss. NSAIDs alleviate pain associated with medical abortion, assist in undertaking natural cycle in-vitro fertilization by preventing follicular rupture and reducing premature ovulation, and serve as tocolytics in preterm labor. New NSAIDs may have a growing role in management of women's health.

Expression and regulation of prostaglandin receptors in the human placenta and fetal membranes at term and preterm

Prostaglandins (PGs) play an important role in parturition in many species, including humans. The present study examined the distribution of PG receptor subtypes (EP1-4 and FP) in intrauterine tissues at term and preterm birth. Placentas and fetal membranes were collected from patients at term in labour (n = 12) or not in labour (n = 12). Preterm tissue was collected from three different groups of patients: (1) idiopathic preterm labour (PTL) without chorioamnionitis or betamethasone (BM) treatment (n = 9), (2) idiopathic PTL that received BM with no chorioamnionitis (PTL-BM; n = 9) and (3) pregnancies that were complicated with chorioamnionitis and had no BM (PTL-CHA; n = 6). EP1-4 and FP receptors were localised and levels of expression were determined by western blot analysis. All EP receptors and FP were localised to the amnion, placenta and choriodecidua. Moreover, isolated amnion mesenchymal, amnion epithelial, chorion trophoblast and syncytiotrophoblast cells in primary culture also expressed PG receptors. A significant increase was observed in EP1, EP3 and FP expression in placenta, chorion and amnion with labour. Maternal betamethasone treatment increased EP1, EP3 and FP receptor protein expression and chorioamnionitis decreased expression in all the receptor subtypes. These changes in PG receptors in the fetal membranes are consistent with the development of a feed-forwards cascade mediated through PG action that may contribute to the birth process.

Chronic infection during placental malaria is associated with up-regulation of cycloxygenase-2

BACKGROUND

Placental malaria (PM) is associated with poor foetal development, but the pathophysiological processes involved are poorly understood. Cyclooxygenase (COX) and lipoxygenase (LOX) which convert fatty acids to prostaglandins and leukotrienes, play important roles in pregnancy and foetal development. COX-2, currently targeted by specific drugs, plays a dual role as it associates with both pre-eclampsia pathology and recovery during infection. The role of COX during PM was questioned by quantifying at delivery COX-1, COX-2, 15-LOX, and IL-10 expression in two groups of malaria infected and uninfected placenta.

METHODS

Placental biopsies were collected at delivery for mRNA isolation and quantification, using real time PCR.

RESULTS

COX-2 and IL-10 mRNAs increased mainly during chronic infections (nine- and five-times, respectively), whereas COX-1 transcripts remained constant. COX-2 over-expression was associated with a higher birth weight of the baby, but with a lower rate of haemoglobin of the mother. It was associated with a macrophage infiltration of the placenta and with a low haemozoin infiltration. In the opposite way, placental infection was associated with lower expression of 15-LOX mRNA. A high degree of haemozoin deposition correlates with low birth weight and decreased expression of COX-2.

CONCLUSION

These data provide evidence that COX-2 and IL-10 are highly induced during chronic infection of the placenta, but were not associated with preterm delivery or low birth weight. The data support the involvement of COX-2 in the recovery phase of the placental infection.

Experience of the use of nimesulide, a cyclo-oxygenase-2 selective prostaglandin synthesis inhibitor, in the prevention of preterm labour in 44 high-risk cases

We report pregnancy outcome and fetal side effects in women at high risk of second trimester loss and early preterm delivery treated with nimesulide. This was a prospective observational study of 44 women treated with nimesulide from 17 to 32 weeks. All women underwent weekly ultrasound scans for AFI, Doppler studies of the ductus arteriosus and transvaginal assessment of cervical length. Outcome data were collected. Oligohydramnios occurred in 54% of cases; this returned to normal in all cases on discontinuation of treatment. There were no cases of constriction of the ductus arteriosus. Thirty-nine women took home a live baby. The mean gestation at delivery was 33 weeks and 1 day and the mean birth weight was 2105 g. Nimesulide appeared to have a significant benefit in women at high risk of preterm delivery with no long-term harmful effects on the fetus if monitored closely with an intensive ultrasound scanning regimen. Randomised placebo controlled trials are required to assess fully the benefit of COX-2 selective and specific prostaglandin synthesis inhibitors.

The cyclopentenone 15-deoxy-delta 12,14-prostaglandin J(2) delays lipopolysaccharide-induced preterm delivery and reduces mortality in the newborn mouse

Intrauterine infection is a common trigger for preterm birth and is also a risk factor for the subsequent development of neurodevelopmental abnormalities in the neonate. Bacterial lipopolysaccharide (LPS) binds to toll-like receptor-4 (TLR-4) to activate proinflammatory signaling pathways, which are implicated in both preterm delivery and antenatal brain injury. The transcription factor nuclear factor-kappaB (NF-kappaB) is a key player in the orchestration of the inflammatory response and has a central role in parturition. Here we show that intrauterine administration of TLR-4-specific LPS to pregnant mice results in the activation of NF-kappaB in the maternal uterus and the fetal brain, up-regulation of proinflammatory proteins cyclooxygenase-2, chemokine ligand 1, ChemoKine (C-C motif) ligand 2, and cytosolic phospholipase A(2) in myometrium, and induction of preterm delivery. 15-Deoxy-Delta(12,14)-prostaglandin J(2) (15d-PGJ(2)) is an antiinflammatory prostaglandin that plays a role in promoting the resolution of inflammation. We report that coadministration of 15d-PGJ(2) and LPS to pregnant mice delays LPS-induced preterm delivery and confers protection from LPS-induced fetal mortality. This is associated with inhibition of myometrial NF-kappaB, cytosolic phospholipase A(2), and c-Jun N-terminal kinase activation, and of inflammatory protein synthesis. Therefore 15d-PGJ(2) has anti-inflammatory effects via inhibition of multiple aspects of inflammation-driven TRL-4 signaling pathway. Thus, 15d-PGJ(2) or compounds with similar antiinflammatory functions may have potential as therapeutic agents in the management of preterm labor with the added advantage of preventing detrimental effects to the fetus that may result from infection/inflammation.

Association of cyclooxygenase-2 and interleukin-1 receptor antagonist gene polymorphisms with the time interval between labor induction and delivery

OBJECTIVE

The interval between induction and delivery may change in association with different polymorphisms in genes regulating inflammation.

STUDY DESIGN

Seventy participants in a trial for induction of labor at term were tested for a -765 G>C cyclooxygenase-2 and an intron 2 length interleukin-1 receptor antagonist gene polymorphism.

RESULTS

The interleukin-1 receptor antagonist allele 2 frequency was 33.3% in the 12 women who delivered at < or =10 hours, compared with 13.8% in those delivered >10 hours (P = .03). The interleukin-1 receptor antagonist allele 2 frequency was 25.0% in women induced because of postdates as opposed to 7.9% induced for other indications (P = .01). The cyclooxygenase-2 allele C frequency was 30.0% in 35 women delivered at < or =20 hours as opposed to 11.4% in women delivered at >20 hours (P = .01). The cyclooxygenase-2 allele C frequency was 26.9% in 26 subjects induced because of postdates as opposed to 13.6% induced for other indications (P = .07).

CONCLUSION

Cyclooxygenase-2 allele C and interleukin-1 receptor antagonist allele 2 are associated with a reduced time interval from labor induction to delivery.

Celecoxib versus magnesium sulfate to arrest preterm labor: randomized trial

AIM

The effectiveness of the management of preterm birth remains an important health care issue, especially when considering that more than two thirds of singleton neonatal death occurs in preterm labor. The purpose of this study was to compare oral celecoxib with intravenous magnesium sulfate as tocolytic.

METHODS

This was a randomized study of patients who were between 24 and 34 weeks of gestation with preterm labor. One hundred and four pregnant women with preterm labor were randomly assigned to receive celecoxib 100 mg b.i.d. for 48 h or intravenous magnesium sulfate (MgSO4) for maximum of 48 h. Outcome variables included delay of delivery for 48 h and the incidence of side-effects. Data was analyzed using the Student t-test and the chi(2) test.

RESULTS

There was no difference between the groups over the course of the study in demographic characteristics, cervical examination and amniotic fluid index. Labor was arrested for 48 h was in 42 (81%) and 45 (87%) of the patients in the celecoxib and magnesium sulfate groups, respectively (p-0.298). There were no severe maternal or neonatal complications in either group.

CONCLUSION

Celecoxib is as effective as magnesium sulfate for primary tocolysis.

A fetal cyclooxygenase-2 gene polymorphism is associated with placental malperfusion

Prostaglandin levels vary during pregnancy, mostly under the control of the inducible enzyme cyclooxygenase-2 (COX-2). The expression of COX-2 has been associated with ischemic events in the heart and brain, but its direct effect on human placental perfusion has not been previously examined. The purpose of this study was to investigate whether a functional polymorphism in the COX-2 gene that controls enzyme expression levels is associated with placental histopathologic lesions. Maternal and neonatal DNA from twin gestations were analyzed by a polymerase chain reaction-based assay for a single G to C nucleotide polymorphism at position -765 in the COX-2 gene promoter. Placental histopathology was evaluated in 6 major categories: meconium, malperfusion, inflammation, umbilical cord problems, villitis, and thrombosis. There was no significant association between placental histopathologic findings and polymorphisms of the COX-2 gene in the mother. In the fetus, carriage of the COX-2 C allele, which is correlated with decreased COX-2 gene expression, was negatively associated with lesions of placental ischemia/malperfusion (P = 0.02). Placental ischemic lesions were positively associated with intrauterine growth restriction (IUGR; P < 0.001). No other group of histopathologic lesions was associated with fetal polymorphisms in the COX-2 gene or with IUGR. Thus, a fetal polymorphism in the COX-2 gene influences the occurrence of placental malperfusion and ischemia, which may be of sufficient severity to promote or allow the development of IUGR.

Novel cyclooxygenase-catalyzed bioactive prostaglandin F2alpha from physiology to new principles in inflammation

Prostaglandin F2alpha (PGF2alpha), a foremost stable vasoactive cyclooxygenase (COX)-catalyzed prostaglandin, regulates a number of key physiological functions such as luteolysis, ovarian function, luteal maintenance of pregnancy, and parturition as a constitutive part of ongoing reproductive processes of the body. It has recently been implicated in the regulation of intricate pathophysiological processes, such as acute and chronic inflammation, cardiovascular and rheumatic diseases. Since the discovery of a second isoform of COXs, it has been shown that PGF2alpha can be formed in vivo from arachidonic acid through both isoforms of COXs, namely cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2). Being synthesized in various parts of the body, it metabolizes instantly to a number of rather inactive metabolites mainly in the lungs, liver, kidney, and efficiently excretes into the urine. 15-Keto-dihydro-PGF2alpha, a major stable metabolite of PGF2alpha that reflects in vivo PGF2alpha biosynthesis, is found in larger quantities than its parent compound in the circulation and urine in basal physiological conditions, with short-lived pulses during luteolysis, induced termination of pregnancy and parturition, and is increased in tissues and various body fluids during acute, sub-chronic, and severe chronic inflammation. Further, the close relationship of PGF2alpha with a number of risk factors for atherosclerosis indicates its major role in inflammation pathology. This review addresses multiple aspects of PGF2alpha in addition to its emerging role in physiology to inflammation.

Feto-placental communication system with the myometrium inpregnancy and parturition: the role of hormones, neurohormones, inflammatory mediators, and locally active factors

Pregnancy is a unique condition in which the conceptus is allowed to implant, survive, develop, and reach a considerable organ growth and maturation within the maternal body despite the fact that it is half genetically different from the mother. Moreover, it deeply influences the overall endocrine, metabolic, and immunological functions of the recipient mother. These objectives are accomplished through the establishment of several communication systems in which a large array of substances produced by the feto-placental unit reach specific maternal target organs and/or systems and modulate their function. The myometrium is a fundamental reproductive tissue involved in pregnancy maintenance as well as in labor onset and progression and is a potential target organ for such a communication system. An appropriate regulation of myometrial function is a key condition required for pregnancy to develop physiologically until full term is reached and for labor to start. Emerging experimental and clinical evidence suggests that a very complex feto-placental biomolecular communication system exists with the myometrium and is actively operative in the control of myometrial contractility in pregnancy and parturition through the production of a continuously increasing number of substances with endocrine, paracrine, and immunoregulatory actions.

Effects of maternally administered drugs on the fetal and neonatal kidney

The number of pregnant women and women of childbearing age who are receiving drugs is increasing. A variety of drugs are prescribed for either complications of pregnancy or maternal diseases that existed prior to the pregnancy. Such drugs cross the placental barrier, enter the fetal circulation and potentially alter fetal development, particularly the development of the kidneys. Increased incidences of intrauterine growth retardation and adverse renal effects have been reported. The fetus and the newborn infant may thus experience renal failure, varying from transient oligohydramnios to severe neonatal renal insufficiency leading to death. Such adverse effects may particularly occur when fetuses are exposed to NSAIDs, ACE inhibitors and specific angiotensin II receptor type 1 antagonists. In addition to functional adverse effects, in utero exposure to drugs may affect renal structure itself and produce renal congenital abnormalities, including cystic dysplasia, tubular dysgenesis, ischaemic damage and a reduced nephron number. Experimental studies raise the question of potential long-term adverse effects, including renal dysfunction and arterial hypertension in adulthood. Although neonatal data for many drugs are reassuring, such findings stress the importance of long-term follow-up of infants exposed in utero to certain drugs that have been administered to the mother.

The role of nuclear factor kappa B in human labour

Preterm birth remains the leading cause of perinatal mortality and morbidity, largely as a result of a poor understanding of the precise mechanisms controlling labour onset in humans. Inflammation has long been recognised as a key feature of both preterm and term labour, with an influx of inflammatory cells into the uterus and elevated levels of pro-inflammatory cytokines observed during parturition. Nuclear factor kappa B (NF-κB) is a transcription factor family classically associated with inflammation. Accumulating evidence points to a role for NF-κB in the physiology and pathophysiology of labour. NF-κB activity increases with labour onset and is central to multiple prolabour pathways. Premature or aberrant activation of NF-κB may thus contribute to preterm labour. The current understanding of NF-κB in the context of human labour is discussed here.

TOCOX--a randomised, double-blind, placebo-controlled trial of rofecoxib (a COX-2-specific prostaglandin inhibitor) for the prevention of preterm delivery in women at high risk

OBJECTIVE

To assess the safety and efficacy of the long term prophylactic use of rofecoxib (a COX-2-specific inhibitor) in women at high risk of preterm delivery.

DESIGN

A randomised, double-blind, placebo-controlled trial.

SETTING

Queen Charlotte's and Chelsea Hospital, London and Guys and St Thomas' Hospitals, London.

POPULATION

Ninety-eight singleton pregnancies at high risk of preterm labour.

METHODS

Treatment from 16 to 32 weeks. Weekly ultrasound surveillance.

MAIN OUTCOME MEASURES

Fetal renal function and ductus arteriosus blood flow changes. Preterm delivery rates and neonatal outcome.

RESULTS

Rofecoxib caused a reduction in hourly fetal urine production rates (-34%, 95% CI -13 to -50%, P = 0.004) and amniotic fluid index (-2.2, 95% CI -3.2 to -1.2, P < 0.001). This effect did not increase with time on treatment and reversed in all cases on discontinuation of treatment. Rofecoxib had an effect on the ductus arteriosus, increasing maximum systolic velocity (0.1 m/s, 95% CI 0.03-0.16, P = 0.02) and minimum diastolic velocity (0.007 m/s, 95% CI 0.0007-0.013, P= 0.03). This effect increased with time on treatment but was reversed with discontinuation of treatment and had no long term clinical sequelae. There was no difference in preterm delivery rates <30 weeks (28% on placebo vs 33% on rofecoxib, Mantel-Haensel [M-H]-adjusted risk 1.11, 95% CI 0.67-1.87). There were more deliveries <37 weeks in those on rofecoxib (40%vs 67%, M-H-adjusted risk 1.59, 95% CI 1.09-2.32). Rates of preterm prelabour rupture of membranes (PPROM) were higher in those on rofecoxib (RR 2.5, 95% CI 1.3-4.7).

CONCLUSION

Rofecoxib has a significant but reversible effect on fetal renal function and the ductus arteriosus. It does not reduce the incidence of early preterm delivery <30 weeks and is associated with an increased risk of delivery before 37 weeks in women at high risk.

Delay of preterm birth in sheep by THG113.31, a prostaglandin F2alpha receptor antagonist

OBJECTIVE

A novel prostaglandin F2alpha receptor antagonist, THG113.31, was tested for the suppression of uterine contractility and delay of preterm labor in sheep.

STUDY DESIGN

We determined the tocolytic effectiveness of THG113.31 on contractions that were stimulated in vitro by prostaglandin F2alpha and E2 in longitudinal and circular myometrial strips. We also tested the ability of THG113.31 in vivo to lower uterine electromyographic activity that was induced by the progesterone receptor blocker, RU486, and to delay preterm birth.

RESULTS

THG113.31 suppressed the amplitude of prostaglandin F2alpha, but not prostaglandin E2-induced contractions of both circular and longitudinal myometrium (P<.01). The times to delivery after RU486 were 34.8+/-1.1 hours (saline solution) and 41.9+/-0.5 hours (THG113.31; P<.001) or an average delay of 7.1 hours. There were no changes in fetal blood gases (PaO2 , PaCO2 , pH, or SaO2) because of THG113.31. Fetal cortisol levels rose in each group, and fetal and maternal prostaglandin E2 and F2alpha metabolite concentrations rose similarly in both groups.

CONCLUSION

THG113.31 specifically suppresses prostaglandin F2alpha-induced myometrial contractility and delays delivery.

Placental expression of enzymes regulating prostaglandin synthesis and degradation

OBJECTIVE

The purpose of this study was to characterize placental expression of the prostaglandin synthase enzymes cyclooxygenase (COX) -1 and -2 and prostaglandin dehydrogenase (PGDH, a degrading enzyme).

STUDY DESIGN

Forty-one women between 20 and 37 weeks' gestation and 39 matched term controls with either spontaneous labor or premature rupture of membranes were enrolled in a prospective case-control study. The relative amounts of placental RNAs at delivery were determined using real-time polymerase chain reaction (PCR).

RESULTS

Placental COX-1 RNA decreased with advancing gestational age at delivery (R(2) = 0.13, P = .001), and increased by 43% when chorioamnionitis was present (P = .006). Among patients presenting at term, oxytocin use was associated with 30% lower expression of COX-1 (P = .01). COX-2 and PGDH were not associated with these variables.

CONCLUSION

Placental COX-1 RNA at delivery decreases with advancing gestational age and with oxytocin use at term. Thus, expression of placental COX-1 is not constitutive. Placental expression of COX-2 and PGDH do not correlate with gestational age, chorioamnionitis, or oxytocin use.

Molecular and biochemical mechanisms of preterm labour

Parturition involves the synchronization of myometrial activity and structural changes of the cervix, leading to regular co-ordinated uterine contractions and cervical dilatation and effacement. The biochemical events involved in parturition resemble an inflammatory reaction, with growing evidence pointing to a crucial role for pro-inflammatory cytokines and prostaglandins in labour. There is accumulating evidence that there are common mediators involved in the regulation of 'labour-associated proteins', and that, in each case, an increase or decrease in gene expression mediates changes in their concentration. It is possible, therefore, that targeting these common mediators may represent newer strategies for the prevention of preterm labour. Our aim is to review the mechanical and biochemical mechanisms that may be involved in the processes of term and preterm labour. Specifically, we will consider the regulation of some of the 'labour-associated proteins', chemotactic cytokines, prostaglandins and enzymes of the prostaglandin biosynthetic pathway and the oxytocin receptor.

Comparison of effects of cyclooxygenase inhibitors on myometrial contraction and constriction of ductus arteriosus in rats

The aim of this study was to compare the tocolytic effect of a selective cyclooxygenase-2 inhibitor, DFU (5,5-dimethyl-3(3-fluorophenyl)-4-(4-methylsulphonyl)phenyl-2(5H)-furanone), indomethacin and nimesulide on myometrial strips isolated from rats in both lipopolysaccharide-induced preterm labour and term labour. We also compared the constrictor effects of DFU and indomethacin on the fetal ductus arteriosus. Myometrial strips were obtained from preterm and term labour Wistar albino rats and were mounted in organ baths for the recording of isometric tension. DFU, nimesulide and indomethacin significantly inhibited KCl-, oxytocin-, prostaglandin E(2)- and prostaglandin F(2 alpha)-stimulated contractions of myometrial strips isolated from rats in preterm and term labour. The E(max) value of indomethacin was significantly lower than those for DFU and nimesulide (P<0.05), with no change-log (10) EC(50) values. There was no significant difference between in -log (10) EC(50) and E(max) values of DFU and nimesulide for any of the tissues (P>0.05). In addition, there was no significant difference between -log (10) EC(50) and E(max) values for each of these three agents in myometrial tissues isolated from rats in preterm and term labour (P>0.05). Fetal ductus arteriosus was significantly constricted by DFU (10 or 100 mg/kg) in preterm and term rats, although DFU (10 or 100 mg/kg)-induced constriction ratios were significantly lower than those for indomethacin (P<0.05). These data demonstrate that DFU, a specific cyclooxygenase-2 inhibitor, could be considered as a new therapeutic agent for preterm labour. However, careful attention should be given to constriction of the fetal ductus arteriosus.

Rofecoxib Versus Magnesium Sulfate to Arrest Preterm Labor: A Randomized Trial

OBJECTIVE

To compare oral rofecoxib with intravenous magnesium sulfate as a tocolytic.

METHODS

This was a randomized study of patients who were between 22 and 34 weeks of gestation with preterm labor. Patients were randomly assigned to receive either daily oral rofecoxib (50 mg) or intravenous magnesium sulfate for a maximum of 48 hours. Outcome variables included delay of delivery for 48 hours and the incidence of side effects. Data were analyzed by using the Student t test, Mann-Whitney U test, chi(2) test, and repeated-measures analysis of variance. Sample size calculations were based on previous studies of tocolytic efficacy.

RESULTS

Two hundred fourteen patients were randomly assigned (105 received rofecoxib and 109 received magnesium sulfate). Delivery was delayed for 48 hours in 95 (90.4%) and 96 (88%) of the patients in the rofecoxib and magnesium sulfate groups, respectively (relative risk 0.97; 95% confidence interval 0.89, 1.06). To show a statistically significant benefit in delay of delivery past 48 hours, a total of 2,686 patients would be required in each group. There was no difference between the groups over the course of the study in cervical dilatation, amniotic fluid index, or cervical length by vaginal ultrasonography. The median hospital days on the original admission were also similar at 2 for both groups (P =.10). There was a higher reported incidence of maternal side effects in the magnesium sulfate group (relative risk 1.81; 95% confidence interval 1.07, 3.06). There was no difference in the incidence of neonatal side effects.

CONCLUSION

There was no difference between oral rofecoxib and intravenous magnesium sulfate in arresting preterm labor.

Transcriptional regulation of genes for enzymes of the prostaglandin biosynthetic pathway

Numerous studies over the years have demonstrated changes in prostaglandin (PG) levels in intrauterine tissues in association with labour, and PG administration has long been used to induce delivery. While it is now widely accepted that PGs play a major role in human parturition, the complex regulation of their levels is still being elucidated, with the focus on the transcriptional control of the enzymes responsible for the various steps in PG biosynthesis and catabolism.

Prostaglandin endoperoxide H synthase inhibitors and other tocolytics in preterm labour

Preterm delivery (<37 weeks of gestation) is the major obstetrical complication in developed countries, yet attempts to delay labour and prolong pregnancy have largely been unsuccessful. One of the many reasons it is so difficult to prevent preterm birth is that the nature of preterm labour changes as a function of gestational age, maternal lifestyle factors or infection, to list a few of the reasons. The inhibitors of prostaglandin endoperoxide H synthase (PGHS), known as the Non-steroidal Antiinflammatory Drugs, have been viewed with interest as tocolytics with promising effectiveness under most conditions of preterm labour. Three isoforms of PGHS exist; the first two, PGHS-1 and -2, have been studied for their catalytic activity, X-ray crystallographic structure, and physiological roles in the adult and the foetus. Mixed inhibitors and isoform-specific inhibitors of PGHS have been developed, and their roles in delaying preterm labour are examined and compared to other tocolytics.

Prostaglandin inhibitors in preterm labour

Prematurity accounts for the majority of neonatal morbidity and mortality in the developed world. The process of labour resembles inflammation, with prostaglandin and cytokine production both before and during labour. Anti-inflammatory drugs therefore have the potential to prevent preterm delivery. Indomethacin is the only tocolytic drug proven to delay delivery beyond 37 weeks and to reduce the incidence of low birth weight (<2500 g). There are, however, fetal side-effects such as ductal constriction and impaired renal function associated with its use. It is the type 2 isoform of cyclo-oxygenase (COX-2), which is important for the production of prostaglandins within intrauterine tissues and that up-regulation of COX-2 is associated with labour. Although indomethacin is currently the most common non-steroidal anti-inflammatory drug (NSAID) used in the treatment of preterm labour, it was hoped that COX-2-selective drugs, used as tocolytics, would target COX-2 activity and potentially spare COX-1-specific fetal side-effects. Experience with sulindac and nimesulide has been linked with both constriction of the ductus arteriosus and oligohydramnios. It is unclear whether this is due to COX-2-dependent side-effects, or due to accumulation of drug in the fetal circulation leading to levels that would cause COX-1 inhibition. Currently, the use of COX-2-selective drugs should therefore be confined to randomized controlled trials.

Myometrial activation and preterm labour: evidence supporting a role for the prostaglandin F receptor--a review

An increase in the myometrial expression of the prostaglandin (PG) receptors, and especially the PGF(2alpha) receptor (FP), may be an important component of the process initiating preterm labour. In this review of the literature and presentation of new possibilities, evidence will be discussed that demonstrates an increase in mouse uterine FP mRNA occurs at preterm birth whereas uterine PGF(2alpha) concentrations do not increase, suggesting elevated uterine receptor expression and sensitivity is a mechanism for preterm labour initiation. The first examination of the complete human myometrial FP promoter will be described and evidence presented that demonstrates the pro-inflammatory cytokine, interleukin-1beta, stimulates FP mRNA expression. Finally new data showing that administration of a specific FP antagonist delays preterm birth in sheep will be presented.

COX-2 inhibitors and their role in gynecology

This review summarizes current knowledge about the roles of cyclooxygenases and prostaglandins in reproductive medicine. With the development of COX-2 specific inhibitors, new therapeutic options are available to obstetricians and gynecologists, offering better-tolerated alternatives to conventional NSAIDs. The analgesic effectiveness of COX-2 specific inhibitors is well established, and they are already in use in a range of painful conditions. Both celecoxib and valdecoxib are indicated for the treatment of primary dysmenorrhea, and may be effective in postoperative pain, including hysterectomy, and pain associated with endometriosis. There is also speculation that COX-2 specific inhibitors may be effective tocolytic agents without the risks to the fetus seen with conventional NSAIDs. The role of COX-2 in oncogenesis is also under investigation, and COX-2 specific inhibitors may eventually be used in the prevention and treatment of gynecologic malignancies.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians Learning Objectives: After completion of this article, the reader will be able to describe the two types of cylooxygenase enzymes (COX), to list the effects and side effects of NSAIDs and COX-2 medications, and to outline the various changes in COX expression during pregnancy.

In vitro study of tocolytic effect of rofecoxib, a specific cyclo-oxygenase 2 inhibitor. Comparison and combination with other tocolytic agents

OBJECTIVE

The aim of this work was to study and compare the tocolytic effects of rofecoxib with indomethacin, ritodrine, nicardipine and atosiban. We also studied the combination of rofecoxib with each agent.

DESIGN

In vitro animal experimental study.

SETTING

Non-selective cyclo-oxygenase (COX) inhibitors have potent tocolytic effect. However, they also have major fetal side effects that seem to be due to COX-1 inhibition. A specific COX-2 inhibitor could be a potent tocolytic agent with less fetal toxicity.

SAMPLE

Myometrial strips from pregnant Wistar rats at 18 days of gestation.

METHODS

Isometric tension was recorded from 112 pregnant rat myometrial strips in vitro. Strips were exposed to increase molar concentration of one drug or combination.

MAIN OUTCOME MEASURES

Contractile activity was assessed by calculating the area under the curve, to obtain a dose-response curve of each drug. EC50 and mean maximal inhibiting concentration were compared using ANOVA. Chemical interaction was defined for each combination.

RESULTS

The in vitro tocolytic effect of rofecoxib was demonstrated. Contractile activity stopped at a concentration of 1.6 x 10(-7) M. Effective concentrations were 1000 times less than for indomethacin and significantly lower than ritodrine and atosiban. Rofecoxib combined with ritodrine had a synergic effect. Other combinations only had an additive effect.

CONCLUSIONS

Rofecoxib has a potent tocolytic effect in vitro. The high specificity and low effective concentrations of COX-2 may result in low fetal toxicity. Animal fetal side effects need to be explored.

The expression of corticotropin-releasing hormone in melanoma

We previously demonstrated that advanced melanoma cells express high amounts of proopiomelanocortin (POMC) that correlate with tumor progression. We now investigated whether the high expression of POMC derives from increased expression of corticotropin-releasing hormone (CRH) and the possible role of CRH as a melanoma growth factor. Forty-five cases of melanoma [25 primary malignant melanoma; 20 metastatic melanoma (MetM)] were immunohistochemically analysed for coexpression of POMC and CRH peptides. The ability of CRH to induce POMC expression in cultured melanoma cells was examined using CRH and a CRH antagonist. In CRH positive melanomas, seven out of nine cases (78%) of primary melanoma, and 7 out of 12 cases (58%) of MetM showed colocalization of CRH and POMC peptides. CRH induced POMC mRNA expression, an effect that was inhibited by a CRH antagonist. These results provide evidence for the existence of the CRH/POMC axis in pigmented lesions.

The effect of thioredoxin on the expression of proopiomelanocortin-derived peptides, the melanocortin 1 receptor and cell survival of normal human keratinocytes

An important constituent of the cellular antioxidant buffering system that controls the redox state of proteins is thioredoxin (TRX), a 13 kDa protein that catalyzes thiol-disulfide exchange reactions, regulates activation of transcription factors, and possesses several other biologic functions similar to cytokines. We have previously reported that TRX released from UVB-irradiated keratinocytes stimulates melanogenesis by upregulating MSH receptor expression and its binding activity in melanocytes. The purpose of this study was to examine the effects of TRX on keratinocytes as an autocrine factor. TRX suppressed the UVB-induced production and secretion of alpha-melanocyte stimulating hormone (alpha-MSH) and of adrenocorticotropic hormone (ACTH), and also suppressed proopiomelanocortin (POMC) mRNA expression by normal human keratinocytes; however, TRX upregulated melanocortin 1 receptor (MC1-R) expression synergistically with UVB in normal human keratinocytes. These results suggest that exogenous TRX regulates expression of those genes in different manners. Furthermore, addition of an antibody against TRX induced cell death in keratinocytes, probably due to enhanced signaling of MSH, as it has been shown that MSH suppresses heat shock protein (hsp) 70 expression in differentiated keratinocytes, which express high levels of MC1-R and decreases their survival rate during oxidative stress. Taken together, the results suggest that keratinocyte-derived TRX regulates the expression of stress inducible neuropeptides and their receptor, and is critically involved in the survival of keratinocytes.

Regulation of prostaglandin biosynthesis in dispersed choriodecidual cells in culture

We have evaluated the prostaglandin (PG) production and PG biosynthetic gene expression in a choriodecidual dispersed cell culture system. Cells dispersed from human choriodecidual membranes by dispase and trypsin digestion were evaluated after 1,3,5 and 7 days of culture for basal and tumour necrosis factor alpha (F-alpha) stimulated PGE2 production. The highest rates of production (P < 0.05) were obtained with cells treated after 3 days of culture, (3.7 +/- 1) x 10(2) pg PGE2 per 16 h per microg total cellular protein (mean +/- SEM), which was 3.9 times basal rate after 3 days culture. In choriodecidual cells treated after 3 days in culture, expression of prostaglandin endoperoxide H synthase-2 (PGHS-2) mRNAwas similarly responsive toTNF-alpha (3.9 times basal within 3 h of 30 ng/ml TNF-alpha) while there was little effect on PGHS-1 or cytosolic phospholipase A2 expression. Hence, the dispersed choriodecidual cell culture system described retainsTNF-alpha responsive PG biosynthetic capacity which is at least in part upregulated via increased expression of PGHS-2 mRNA.

Anaphylactoid reactions associated with menstruation affecting two sisters

Cyclical anaphylactoid reactions associated with menstruation are exceedingly rare. We report two sisters who were both affected, one severely and one mildly. Treatment involved suppression of menstruation and use of a cyclooxygenase-2 (COX-2) inhibitor. An abnormal reaction to prostaglandins, perhaps produced by COX-2 enzyme activity in the endometrium, is a possible mechanism.

Expression of prostaglandin H synthase-1 and -2 in murine intrauterine and gestational tissues from mid pregnancy until term

These studies were undertaken to evaluate the changes in mRNA expression of prostaglandin H synthase (PGHS)-1 and -2 in murine gestational tissues during the latter half of pregnancy. Gestational tissues (decidual caps, membranes surrounding the fetus, and placentae), uterus, and cervix were collected from pregnant mice at days 12, 14, 16, 18, and 19 (am and pm) of gestation (n = 4), and total RNA was isolated and evaluated for PGHS-1 and PGHS-2 expression by northern blot analysis. Expression was normalized to GAPDH. There were no significant increases in PGHS-2 mRNA expression in any of the tissues studied through gestation. In contrast, expression of PGHS-1 mRNA increased significantly at term in the uterus and fetal membranes. In the placenta, mRNA for PGHS-1 was elevated at day 18 and remained elevated over the remainder of the study. These findings suggest that, in the mouse, increased production of PGs by uterine and intrauterine tissues during pregnancy is associated with up-regulation of PGHS-1 and not PGHS-2.

Expression of cyclooxygenase-2 and prostanoid receptors by human myometrium

Prostanoids play an important role in the regulation of parturition. All reproductive tissues, including fetal membranes, decidua, and myometrium, have the capacity to synthesize prostanoids, and fetal membranes have been shown to express elevated levels of cyclooxygenase-2 (Cox-2) at the onset of labor. We have now investigated the expression of Cox-2 in human myometrium. Myometrial samples collected from women in labor during lower segment cesarean section expressed 15-fold higher levels of Cox-2 messenger ribonucleic acid (mRNA) compared to myometrial specimens collected from women not in labor, as detected by Northern blot analysis. Immunohistochemical detection of Cox-2 protein showed cytoplasmic staining in the smooth muscle cells of the myometrium. Cultured myometrial cells expressed low levels of Cox-2 mRNA under baseline conditions, but interleukin-1beta (IL-1beta) caused a 17-fold induction of expression of the Cox-2 transcript after incubation for 6 h. IL-1beta also induced expression of biologically active Cox-2 protein, as detected by immunofluorescence, Western blot analysis, and measuring the conversion of arachidonic acid to prostanoids in the presence and absence of a Cox-2-selective inhibitor, NS-398. PGE2 receptor subtype EP2 mRNA was expressed in cultured myometrial smooth muscle cells, whereas transcripts for EP1, EP3, EP4, FP, and IP were low or below the detection limit as measured by Northern blot analysis. However, IL-1beta stimulated expression of EP4 receptor mRNA. Our data suggest that expression of Cox-2 transcript is elevated at the onset of labor in myometrial smooth muscle cells, which may depend on induction by cytokines. As, in addition to Cox-2, the expression of prostanoid receptors is regulated, not only the production of prostanoids, but also responsiveness to them, may be modulated.

Prostaglandin endoperoxide H synthase mRNA expression in the fetal membranes correlates with fetal fibronectin concentration in the cervico-vaginal fluids at term: evidence of enzyme induction before the onset of labour

OBJECTIVE

To determine the relationship of prostaglandin endoperoxide H synthase (PGHS) expression in the gestational tissues and fetal fibronectin in cervico-vaginal fluids before the onset of labour at term.

DESIGN

Cross-sectional, observational study.

SAMPLES

Amnion, chorion laeve and decidua were collected from 24 term pregnant women following elective caesarean section. Samples of cervico-vaginal secretions were obtained from the same women immediately before caesarean section.

METHODS

PGHS-1 and PGHS-2 mRNA levels in tissues were determined by specific ribonuclease protection assays. Fetal fibronectin concentrations in the cervico-vaginal fluids were measured by enzyme-linked immunosorbent assay. The abundance of PGHS mRNA was compared between groups of patients with the same mean gestational age but different cervico-vaginal fetal fibronectin levels. Linear regression analysis was used to determine the association between PGHS levels and fetal fibronectin.

RESULTS

Two groups of women were identified who had significantly different fetal fibronectin values but the same gestational ages. The group with the higher fetal fibronectin concentrations had significantly higher PGHS- 1 and PGHS-2 mRNA levels in the chorion laeve and higher PGHS-2 mRNA levels in the amnion, than the group with lower fetal fibronectin concentrations. PGHS- 1 and PGHS-2 mRNA levels in the chorion laeve and PGHS-2 mRNA in the amnion showed an overall significant association with fetal fibronectin levels.

CONCLUSIONS

High concentrations of fetal fibronectin in cervico-vaginal secretions before the onset of spontaneous labour at term are associated with high levels of PGHS-2 mRNA in the chorion laeve and the amnion and of PGHS- 1 mRNA in the chorion laeve. Increased expression of PGHS in these tissues may therefore be involved in the events leading to term birth.