Safety, tolerability, and acceptability of Lactobacillus crispatus CTV-05 (LACTIN-V) in pregnant women at high-risk of preterm birth

The vaginal microbiota is a determinant for the risk of preterm birth (PTB). Dominance of the vaginal niche by Lactobacillus crispatus associates with term delivery. This is the first observational clinical study of live vaginal biotherapeutics (Lactobacillus crispatus CTV-05 (LACTIN-V)) in pregnant women at high-risk of PTB. The primary aim was to explore safety, tolerability and acceptability of LACTIN-V in pregnancy. Women were offered a course of LACTIN-V at 14 weeks gestation for five consecutive days followed by weekly administration for six weeks. Participants were followed up at 15, 18-, 20-, 28- and 36-weeks' gestation and at delivery for assessment of adverse events, compliance and tolerability. Participants completed a questionnaire to gauge experience and acceptability. In total, 73 women were recruited, of whom eight withdrew, leaving a final cohort size of 61. Self-reported compliance to the course was high (56/60, 93%). Solicited adverse events were reported in 13 women (19%) including changes in vaginal discharge, odour, colour or consistency of urine, itching and vaginal bleeding. One unsolicited adverse event was reported as haematuria at 38 weeks gestation, but was judged to be unrelated to LACTIN-V. No serious adverse events occurred. One mild adverse event led to study withdrawal. Thirty-one women completed an experience and acceptability questionnaire. Women found LACTIN-V easy and comfortable to use and the majority (30/31, 97%) would use LACTIN-V in future pregnancies. Eight women (8/31, 26%) found the schedule of use difficult to remember. The rate of PTB <34 weeks in this cohort was 3.3% compared to 7% in a historical cohort of 2,190 women at similar background PTB risk. With satisfactory uptake and good compliance, we demonstrate that LACTIN-V is safe and accepted in pregnancy, with high tolerability. Further studies are needed to assess colonisation of Lactobacillus crispatus CTV-05 and clinical efficacy.

The association between vaginal bacterial composition and miscarriage: a nested case-control study

Objective

To characterise vaginal bacterial composition in early pregnancy and investigate its relationship with first and second trimester miscarriages.

Design

Nested case–control study.

Setting

Queen Charlotte’s and Chelsea Hospital, Imperial College Healthcare NHS Trust, London.

Population

161 pregnancies: 64 resulting in first trimester miscarriage, 14 in second trimester miscarriage and 83 term pregnancies.

Methods

Prospective profiling and comparison of vaginal bacteria composition using 16S rRNA gene‐based metataxonomics from 5 weeks’ gestation in pregnancies ending in miscarriage or uncomplicated term deliveries matched for age, gestation and body mass index.

Main outcome measures

Relative vaginal bacteria abundance, diversity and richness. Pregnancy outcomes defined as first or second trimester miscarriage, or uncomplicated term delivery.

Results

First trimester miscarriage associated with reduced prevalence of Lactobacillus spp.‐dominated vaginal microbiota classified using hierarchical clustering analysis (65.6 versus 87.7%; P = 0.005), higher alpha diversity (mean Inverse Simpson Index 2.5 [95% confidence interval 1.8–3.0] versus 1.5 [1.3–1.7], P = 0.003) and higher richness 25.1 (18.5–31.7) versus 16.7 (13.4–20), P = 0.017), compared with viable pregnancies. This was independent of vaginal bleeding and observable before first trimester miscarriage diagnosis (P = 0.015). Incomplete/complete miscarriage associated with higher proportions of Lactobacillus spp.‐depleted communities compared with missed miscarriage. Early pregnancy vaginal bacterial stability was similar between miscarriage and term pregnancies.

Conclusions

These findings associate the bacterial component of vaginal microbiota with first trimester miscarriage and indicate suboptimal community composition is established in early pregnancy. While further studies are required to elucidate the mechanism, vaginal bacterial composition may represent a modifiable risk factor for first trimester miscarriage.

Tweetable abstract

Vaginal bacterial composition in first trimester miscarriage is associated with reduced Lactobacillus spp. abundance and is independent of vaginal bleeding.

Vaginal bacterial composition in first trimester miscarriage is associated with reduced Lactobacillus spp. abundance and is independent of vaginal bleeding.

The vaginal microbiome in uterine transplantation

Women with congenital absolute uterine factor infertility (AUFI) often need vaginal restoration to optimise sexual function. Given their lack of procreative ability, little consideration has previously been given to the resultant vaginal microbiome (VM). Uterine transplantation (UTx) now offers the opportunity to restore these women's reproductive potential. The structure of the VM is associated with clinical and reproductive implications that are intricately intertwined with the process of UTx. Consideration of how vaginal restoration methods impact VM is now warranted and assessment of the VM in future UTx procedures is essential to understand the interrelation of the VM and clinical and reproductive outcomes. TWEETABLE ABSTRACT: The vaginal microbiome has numerous implications for clinical and reproductive outcomes in the context of uterine transplantation.

Prospective observational study of vaginal microbiota pre- and post-rescue cervical cerclage

OBJECTIVE

To investigate the relation between vaginal microbiota composition and outcome of rescue cervical cerclage.

DESIGN

Prospective observational study.

SETTING

Queen Charlotte's and Chelsea Hospital, London.

POPULATION

Twenty singleton pregnancies undergoing a rescue cervical cerclage.

METHODS

Vaginal microbiota composition was analysed in women presenting with a dilated cervix and exposed fetal membranes before and 10 days following rescue cervical cerclage and was correlated with clinical outcomes.

MAIN OUTCOME MEASURES

Composition of vaginal bacteria was characterised by culture-independent next generation sequencing. Successful cerclage was defined as that resulting in the birth of a neonate discharged from hospital without morbidity. Unsuccessful cerclage was defined as procedures culminating in miscarriage, intrauterine death, neonatal death or significant neonatal morbidity.

RESULTS

Reduced Lactobacillus spp. relative abundance was observed in 40% of cases prior to rescue cerclage compared with 10% of gestation age-matched controls (8/20, 40% versus 3/30, 10%, P = 0.017). Gardnerella vaginalis was over-represented in women presenting with symptoms (3/7, 43% versus 0/13, 0%, P = 0.03, linear discriminant analysis, LDA (log 10) and cases culminating in miscarriage (3/6, 50% versus 0/14, 0%, P = 0.017). In the majority of cases (10/14, 71%) bacterial composition was unchanged following cerclage insertion and perioperative interventions.

CONCLUSIONS

Reduced relative abundance of Lactobacillus spp. is associated with premature cervical dilation, whereas high levels of G. vaginalis are associated with unsuccessful rescue cerclage cases. The insertion of a rescue cerclage does not affect the underlying bacterial composition in the majority of cases.

TWEETABLE ABSTRACT

Preterm cervical dilatation associates with reduced Lactobacillus spp. Presence of Gardnerella vaginalis predicts rescue cerclage failure.

Progesterone and the Repression of Myometrial Inflammation: The Roles of MKP-1 and the AP-1 System

Progesterone (P4) maintains uterine quiescence during pregnancy and its functional withdrawal is associated with increased prostaglandin synthesis and the onset of labor. In primary human myometrial cells, the glucocorticoid receptor (GR) rather than the P4 receptor mediates P4 antagonism of IL-1β-induced cyclooxygenase-2 (COX-2) expression, the rate-limiting enzyme in prostaglandin synthesis. We now report that P4 also acts via GR to induce MAPK phosphatase (MKP)-1 and knockdown of MKP-1 impairs the ability of P4 to repress IL-1β-dependent COX-2 induction. Microarray analysis revealed that P4 repressed preferentially activator protein-1-responsive genes in response to IL-1β. Consistent with these observations, we found that the ability of P4 to reduce c-Jun activation was lost upon GR as well as MKP-1 knockdown. Interestingly, c-Jun levels in human myometrial cells declined upon GR and MKP-1 knockdown, which suggests the presence of an activator protein-1 feedback loop. This is supported by our observation that c-Jun levels declined after an initial rise in primary myometrial cells treated with phorbol 12-myrisatate 13-acetate, a potent activator of c-Jun N-terminal kinase. Finally, we show that MKP-1 is an intermediate in P4-mediated repression of some but not all IL-1β-responsive genes. For example, P4 repression of IL11 and IRAK3 was maintained upon MKP-1 knockdown. Taken together, the data show that P4 acts via GR to drive MKP-1 expression, which in turn inhibits IL-1β-dependent c-Jun activation and COX-2 expression.

Uterine stretch and progesterone action

CONTEXT

Progesterone administration reduces the risk of preterm labor in high-risk women with singleton pregnancies but has no effect in women with a multiple pregnancy.

OBJECTIVE

We investigated whether progesterone is able to inhibit stretch-induced gene expression and/or whether stretch in turn inhibits progesterone action, perhaps providing an explanation for the functional progesterone withdrawal associated with human labor.

METHODS AND RESULTS

In a series of in vitro studies using primary cultures of human myometrial cells, we found that preincubation with progesterone did not block stretch-induced ERK1/2 activation and cyclooxygenase-2 mRNA expression. Furthermore, we found that stretch did not alter the ability of progesterone to: 1) modulate progesterone-responsive gene expression; 2) activate a luciferase-linked progesterone response element; or 3) repress IL-1β-driven cyclooxygenase-2 mRNA expression. We did find that stretch reduced the expression of progesterone receptor mRNA via nuclear factor κB activation but that this did not alter myometrial progesterone response.

CONCLUSION

These data show that progesterone does not inhibit stretch-induced MAPK activation or gene expression, possibly explaining why progesterone is ineffective in the prevention of preterm labor in multiple pregnancy. Although stretch did reduce progesterone receptor expression in a nuclear factor κB-dependent manner, this was not sufficient to inhibit progesterone action, suggesting that it is not responsible for the functional progesterone withdrawal observed with the onset of human labor.

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.

Prostaglandin F2-alpha receptor regulation in human uterine myocytes

Investigations of the modulation of prostaglandin F(2alpha) receptor (FP) expression in primary cultures of human uterine myocytes showed that FP mRNA expression was reduced by progesterone, unaltered by cAMP (8-bromo cAMP or forskolin), but increased by the PKA antagonist H89. Interleukin (IL)-1beta, tumour necrosis factor-alpha and oxytocin increased FP mRNA expression and IL-6 and prostaglandin E(2) reduced FP mRNA expression. The changes in FP protein levels were similar to the mRNA responses. We found that the IL-1beta-induced increase in FP expression was mediated at least in part via protein kinase C (PKC), but was independent of mitogen-activated protein kinase, phospholipase C and PI3 kinase. Since IL-1beta activates NFkappaB, AP-1 and C/EBP, we over-expressed these transcription factors alone and in combination and found that only NFkappaB alone increased FP mRNA expression. Finally, we found that the IL-1beta-induced increase in FP expression was unaffected by progesterone and/or cAMP, but was accentuated by H89. These data suggest that the pregnancy-induced down-regulation in myometrial FP expression is mediated by progesterone and cAMP and that the increase with labour is induced by inflammatory cytokine activation of PKC and NFkappaB.

Stretch and interleukin 1 beta: Pro-labour factors with similar mitogen-activated protein kinase effects but differential patterns of transcription factor activation and gene expression

IL-1beta and stretch increase uterine smooth muscle cell (USMC) prostaglandin H synthase 2 (PGHS-2) and interleukin (IL)-8 mRNA expression in a mitogen-activated protein kinase (MAPK) dependent mechanism. We have tested our hypothesis that stretch and IL-1beta activate different components of the MAPK cascade in USMC and investigated the effects of specific MAPK inhibitors on these components. Further, we have used a Jun N-terminal kinase (JNK) and p38 activator, anisomycin, to compare the effect of differential MAPK activation on the expression of PGHS-2, IL-8 and oxytocin receptor (OTR) mRNA with that seen in response to stretch and IL-1beta. Stretch, IL-1beta and anisomycin activated similar components of the MAPK cascade and specific inhibitors of MAPK altered phosphorylation of MAPK and downstream cascade components as expected. Expression of OTR mRNA was increased by stretch and anisomycin in a MAPK-independent manner. All three stimuli increased PGHS-2 and IL-8 mRNA expression in a MAPK-dependent manner, but while the MAPK inhibitors reduced the IL-1beta-induced activation of activating transcription factor (ATF)-2, liver activating protein (LAP) and c-jun, the stretch-induced increase in LAP was unaffected by MAPK-inhibition and only JNK inhibition appeared to reduce c-jun activation. These observations show that stretch, IL-1beta and anisomycin activate the same components of the MAPK cascade, but differentially activate LAP and liver inhibitory protein (LIP) perhaps accounting for the increase in OTR by stretch and anisomycin but not IL-1beta observed in this study.

Prostanoid receptors in human uterine myocytes: the effect of reproductive state and stretch

In the human, prostanoids are known to be important mediators of uterine relaxation and contraction during pregnancy and parturition. We have previously shown that stretch of uterine smooth muscle cells increased prostaglandin H synthase 2 (PGHS-2) mRNA expression, PGHS-2 peptide synthesis and activity, however, the net effect on uterine contractility of this increase in prostaglandin synthesis would be determined by the expression of the different prostanoid receptors. Therefore, the aims of this study were to establish the expression of prostanoid receptor mRNA in uterine myocytes obtained from women in different reproductive states and to test the hypothesis that stretch of uterine myocytes alters prostanoid receptor mRNA expression to promote uterine contractility. Myocytes were isolated from women undergoing hysterectomy (NP) and pregnant women undergoing LSCS either before (NL) or after the onset of labour (L) and were subjected to 11% stretch for 1 h (n = 6 in all cases). Copy numbers of the individual receptors varied widely with reproductive state but followed the pattern: FP > IP = DP = EP-4 > TP = EP-3 = EP-2 > EP-1. FP mRNA expression was significantly lower in the NL group compared to the NP group and EP-3, EP-4 and TP mRNA expression was significantly lower in both NL and L groups compared to NP group levels. The level of mRNA expression of EP-1, EP-2, DP and IP did not differ between NP, NL and L groups. Stretch of cells derived from the NP group resulted in a significant decrease in EP-4 mRNA expression alone and of the NL group a significant decrease in EP-2 mRNA expression alone. Stretch had no effect on cells derived from the L group. These data show that pregnancy is associated with a significant reduction in 3 of 4 pro-contraction associated prostanoid receptor mRNA expression and 1 of 4 pro-relaxant. Stretch elicited no consistent change in prostanoid receptor mRNA expression.

The mitogen-activated protein kinase dependent expression of prostaglandin H synthase-2 and interleukin-8 messenger ribonucleic acid by myometrial cells: the differential effect of stretch and interleukin-1{beta}

Infection and uterine stretch are the common causes of preterm labor. IL-1beta plays a key role in infection-induced preterm labor and increases prostaglandin H synthase 2 (PGHS-2) and IL-8 expression. We have shown that mechanical stretch of uterine myocytes in vitro up-regulates the expression of PGHS-2 and IL-8. In this study, we tested the hypotheses that both IL-1beta and mechanical stretch increase the myometrial expression of PGHS-2 and IL-8 via MAPK activation and that their effects are synergistic. MAPK activation was assessed in myocytes obtained from pregnant women undergoing cesarean section before the onset of labor after exposure to IL-1beta and stretch either alone or in combination. Specific inhibitors of ERK, p38, and c-Jun N-terminal kinase were used to define the role of each in the increased expression of PGHS-2 and IL-8 mRNA. We found that both IL-1beta and stretch activated all three MAPK subtypes but that they had no synergistic effect. The inhibitor studies showed that stretch-induced increases in both PGHS-2 and IL-8 mRNA expression were ERK1/2 and p38 dependent and that IL-1beta-induced increases of PGHS-2 mRNA expression were also ERK1/2 and p38 dependent, but those of IL-8 were dependent only on ERK1/2 activation. These data show that exposure of human uterine myocytes to both stretch and IL-1beta activates the MAPK system, which is responsible for the increase in PGHS-2 and IL-8 mRNA expression. We found no evidence of a synergistic effect of IL-1beta and stretch on myometrial expression of PGHS-2 and IL-8 mRNA.

Mechanical stretch of human uterine smooth muscle cells increases IL-8 mRNA expression and peptide synthesis

Labour is associated with increased synthesis of interleukin-8 (IL-8) by the fetal membranes and myometrium, which leads to an inflammatory infiltrate. Stretch has been shown to increase the expression of contraction-associated proteins in animal models of labour and in human myocytes in vitro. In this study, we tested the hypothesis that mechanical stretch of human myometrial cells increases IL-8 messenger ribonucleic acid (mRNA) expression. We isolated myocytes from non-pregnant women undergoing hysterectomy and pregnant women undergoing Caesarean section before and after the onset of labour. Myocytes in culture were subjected to stretch of varying intensity (6-16%) and duration (1 or 6 h) using the Flexercell system. IL-8 mRNA expression was lowest in myocytes from pregnant women not in labour, intermediate in those from non-pregnant women and greatest in those from pregnant women in labour. Stretch increased IL-8 mRNA expression independent of reproductive state. The stretch-induced increase in IL-8 mRNA expression was associated with higher IL-8 levels in the culture supernatant and enhanced promoter activity. These data suggest that stretch contributes to the increase in myometrial IL-8 synthesis associated with the onset of labour in humans.

Mechanical stretch activates type 2 cyclooxygenase via activator protein-1 transcription factor in human myometrial cells

The uterus is subject to stretch throughout pregnancy, which, in the presence of progesterone, is a potent stimulus for uterine growth. However, in the absence of progesterone or when stretch is excessive, as in multiple pregnancy, it may provoke the onset of labour. We have investigated the effect of stretch on prostaglandin synthesis in primary human uterine myocytes [non-pregnant (NP), pregnant not in labour (NL) and pregnant in labour (L)]. The cells were grown on flexible bottom culture plates and subjected to 1 or 6 h static stretch. Expression of type 2 cyclooxygenase (COX-2) mRNA was similar in samples obtained from NP and L groups and both were significantly greater than those found in the NL group. Stretch of cells from all groups resulted in increased COX-2 mRNA expression. In further studies carried out on cells taken from the NL group, 6 h of stretch resulted in increased COX-2 protein levels and, in the media, increases in prostaglandin (PG) I(2) metabolite and PGE(2) concentrations and a reduction in the concentration of PGF(2)alpha metabolites. After stretch, EMSA studies showed increased activator protein-1 (AP-1) nuclear protein DNA binding activity but not of nuclear factor kappaB. These data demonstrate that stretch of human myocytes results in increased COX-2 activity and suggest that this may occur through activation of the AP-1 system.

Identification of fetal mesenchymal stem cells in maternal blood: implications for non-invasive prenatal diagnosis

Strategies for genetic prenatal diagnosis on fetal cells in the maternal circulation have been limited by lack of a cell type present only in fetal blood. However, the recent identification of mesenchymal stem cells (MSC) in first trimester fetal blood offers the prospect of targeting MSC for non-invasive prenatal diagnosis. We developed protocols for fetal MSC enrichment from maternal blood and determined sensitivity and specificity in mixing experiments of male fetal MSC added to female blood, in dilutions from 1 in 10(5) to 10(8). We then used the optimal protocol to isolate fetal MSC from maternal blood in the first trimester, using blood taken after surgical termination of pregnancy as a model of increased feto-maternal haemorrhage. In model mixtures, we could amplify one male fetal MSC in 2.5 x 10(7) adult female nucleated cells, yielding a 100% pure population of fetal cells, but not one fetal MSC in 10(8) nucleated cells. Fetal MSC were identified in one of 20 post-termination maternal blood samples and confirmed as fetal MSC by XY fluorescence in-situ hybridization (FISH), immunophenotyping and osteogenic and adipogenic differentiation. We report the isolation of fetal MSC from maternal blood; however, their rarity in post-termination blood suggests they are unlikely to have a role in non-invasive prenatal diagnosis. Failure to locate these cells routinely may be attributed to their low frequency in maternal blood, to sensitivity limitations of enrichment technology, and/or to their engraftment in maternal tissues soon after transplacental passage. We speculate that gender microchimerism in post-reproductive maternal tissues might result from feto-maternal trafficking of MSC in early pregnancy.

The effects of a cytokine suppressive anti-inflammatory drug on the output of prostaglandin E(2) and interleukin-1 beta from human fetal membranes

Fetal membranes are a primary source of prostaglandins and pro-inflammatory cytokines implicated in human parturition, so the inhibition of inflammatory pathways may be of benefit in pregnancies complicated by premature labour. We have therefore investigated the effects of a cytokine-suppressant anti-inflammatory drug (CSAID) on the output of prostaglandin E(2) (PGE(2)) and interleukin (IL)-1 beta from human fetal membranes in vitro. Bacterial endotoxin increased the expression of mRNA for IL-1 beta and type-2 cyclo-oxygenase (COX-2), and there were corresponding increases in the output of IL-1 beta protein and PGE(2). The CSAID decreased IL-1 beta protein, COX-2 expression and PGE(2) output, but not mRNA for IL-1 beta, indicating a post-translational effect on the production of IL-1 beta and a transcriptional affect on COX-2, with an overall reduction in PGE(2). These findings are consistent with the effects of CSAIDs in other systems, and indicate that they are of possible use in premature labour.

Identification of mesenchymal stem/progenitor cells in human first-trimester fetal blood, liver, and bone marrow

Human mesenchymal stem/progenitor cells (MSCs) have been identified in adult bone marrow, but little is known about their presence during fetal life. MSCs were isolated and characterized in first-trimester fetal blood, liver, and bone marrow. When 10(6) fetal blood nucleated cells (median gestational age, 10(+2) weeks [10 weeks, 2 days]) were cultured in 10% fetal bovine serum, the mean number (+/- SEM) of adherent fibroblastlike colonies was 8.2 +/- 0.6/10(6) nucleated cells (69.6 +/- 10/microL fetal blood). Frequency declined with advancing gestation. Fetal blood MSCs could be expanded for at least 20 passages with a mean cumulative population doubling of 50.3 +/- 4.5. In their undifferentiated state, fetal blood MSCs were CD29(+), CD44(+), SH2(+), SH3(+), and SH4(+); produced prolyl-4-hydroxylase, alpha-smooth muscle actin, fibronectin, laminin, and vimentin; and were CD45(-), CD34(-), CD14(-), CD68(-), vWF(-), and HLA-DR(-). Fetal blood MSCs cultured in adipogenic, osteogenic, or chondrogenic media differentiated, respectively, into adipocytes, osteocytes, and chondrocytes. Fetal blood MSCs supported the proliferation and differentiation of cord blood CD34(+) cells in long-term culture. MSCs were also detected in first-trimester fetal liver (11.3 +/- 2.0/10(6) nucleated cells) and bone marrow (12.6 +/- 3.6/10(6) nucleated cells). Their morphology, growth kinetics, and immunophenotype were comparable to those of fetal blood-derived MSCs and similarly differentiated along adipogenic, osteogenic, and chondrogenic lineages, even after sorting and expansion of a single mesenchymal cell. MSCs similar to those derived from adult bone marrow, fetal liver, and fetal bone marrow circulate in first-trimester human blood and may provide novel targets for in utero cellular and gene therapy.

IL-1beta and IL-8 in human fetal membranes: changes with gestational age, labor, and culture conditions

PROBLEM

Interleukin (IL)-1beta and IL-8 are associated with labor. This study aimed to characterize their concentrations in fetal membranes and any changes in these with advancing gestation and to define as to whether there are interactions between the membranes in their expression.

METHOD OF STUDY

mRNA and protein content of amnion and choriodecidua at increasing gestations and before and after labor at term were quantified. Membranes were also collected before and after labor, separated, and cultured. Protein production was measured by ELISA.

RESULTS

IL-1beta and IL-8 concentration increased in third trimester amnion and choriodecidua. Further increased expression of mRNA of both cytokines was found after labor in both membranes except IL-8 production by amnion. Choriodecidua produced more of each cytokine than amnion, however, no interaction between the membranes was demonstrated by culture.

CONCLUSIONS

Increasing expression of IL-1beta and IL-8 in amnion and choriodecidua in the third trimester and after labor supports a role for these cytokines in the establishment of labor.

Progesterone receptor isoform A inhibits isoform B-mediated transactivation in human amnion

Human amnion cells were transfected with progesterone receptor A and/or B, and the progesterone-dependent reporter construct, mouse mammary tumor virus promoter (MMTV), linked to a luciferase gene. In progesterone receptor B-expressing amnion that had been cultured before the onset of labour, treatment with progesterone resulted in an eightfold increase of the reporter activity, whereas in laboured cells, no such increase was seen. In contrast, progesterone receptor A was a weak activator of transcription in laboured and non-laboured amniocytes. When the isoforms A and B of the progesterone receptor were co-transfected, progesterone receptor A exhibited a marked inhibitory effect on progesterone receptor B-mediated transcription. These results show that progesterone receptors A and B function differentially, and progesterone receptor A is a transdominant repressor of progesterone receptor B-mediated transcription in human term amnion.

Interactions between progesterone receptor isoforms in myometrial cells in human labour

Progesterone acts to maintain uterine quiescence during pregnancy. In contrast to many other species, no decrease in maternal serum levels of progesterone can be observed in humans before the onset of labour. Therefore, a 'functional' progesterone withdrawal in association with labour has been proposed. In humans the progesterone receptor (PR) exists in two isoforms, PR-A and PR-B. While PR-B generally mediates the effects of progesterone upon gene transcription, the role of PR-A during pregnancy, and in parturition, is unknown. In this study, term myometrium cells cultured before the onset of labour were transiently transfected with expression vectors for either PR-A or PR-B. Only those cells expressing PR-B significantly increased expression of a progesterone-sensitive reporter when stimulated with progesterone. Co-transfection of both isoforms of PR demonstrated that PR-A is a dominant repressor of transactivation in these cells. Western blot analysis showed that PR-A is present in human myometrium samples taken only after, but not before, the onset of labour. These data suggest that increased expression of PR-A in human myometrium may contribute to 'functional' progesterone withdrawal and the initiation of human labour.

Nuclear factor-kappa B is essential for up-regulation of interleukin-8 expression in human amnion and cervical epithelial cells

Interleukin-8 (IL-8) is a cytokine which recruits and activates neutrophils into tissue stroma. It is present in uterine tissues and its concentration increases in the third trimester and with labour. The promoter region of the IL-8 gene contains binding sites for the transcription factors, nuclear factor-kappa B (NF-kappaB), activator protein-1 (AP-1) and CCAAT/enhancer-binding protein (C/EBP). These are in close proximity to each other and to the coding region of the gene. This study used site-directed mutagenesis of each of these sites to examine the relative importance of each site in IL-8 gene expression in a cervical cell line and in amnion cells obtained before and after labour. We found that the NF-kappaB site was essential for basal and IL-1beta-stimulated gene expression in all cell types. Neither of the other binding sites was consistently essential for gene expression but may have an additive role in promoter activity. We conclude that the NF-kappaB binding site is essential for up-regulation of IL-8 gene expression in these uterine cell types. An increase in IL-8 expression has been shown to occur in the uterus in association with parturition and NF-kappaB binding to the promoter may be of importance at this time.

Simultaneous fetal cell identification and diagnosis by epsilon-globin chain immunophenotyping and chromosomal fluorescence in situ hybridization

Isolating fetal erythroblasts from maternal blood offers a promising noninvasive alternative for prenatal diagnosis. The current immunoenzymatic methods of identifying fetal cells from background maternal cells postenrichment by labeling gamma-globin are problematic. They are nonspecific because maternal cells may produce gamma-globin, give poor hybridization efficiencies with chromosomal fluorescence in situ hybridization (FISH), and do not permit simultaneous visualization of the fetal cell identifier and the FISH signal. We describe a novel technique that allows simultaneous visualization of fetal erythroblast morphology, chromosomal FISH, and epsilon-globin labeled with AMCA (7-amino-4-methylcoumarin-3-acetic acid). AMCA was chosen as the fluorescent label to circumvent the problem of heme autofluorescence because the mean difference in relative fluorescence intensity between fetal erythroblasts stained positive for antiglobin antibody and autofluorescence of unstained cells was greater with AMCA (mean 43.2; 95% confidence interval [CI], 34.6-51.9; SD = 14.0) as the reporting label compared with fluorescein isothiocyanate (mean 24.2; 95% CI, 16.4-31.9; SD = 12.4) or phycoerythrin (mean 9.8; 95% CI, 4.8-14.8; SD = 8.0). Median FISH hybridization efficiency was 97%, comparable to the 98% (n = 5 paired samples) using Carnoy fixative. One epsilon-positive fetal erythroblast was identified among 10(5) maternal nucleated cells in 6 paired mixture experiments of fetal erythroblasts in maternal blood (P <.001). Male epsilon-positive fetal erythroblasts were clearly distinguishable from adult female epsilon-negative erythroblasts, with no false positives (n = 1000). The frequency of fetal erythroblasts expressing epsilon-globin declines linearly from 7 to 14 weeks' gestation (y = -15.8 x + 230.8; R(2) = 0.8; P <.001). We describe a rapid and accurate method to detect simultaneously fetal erythroblast morphology, intracytoplasmic epsilon-globin, and nuclear FISH. (Blood. 2001;98:554-557)

Human labour is associated with nuclear factor-kappaB activity which mediates cyclo-oxygenase-2 expression and is involved with the 'functional progesterone withdrawal'

Human labour is associated with the up-regulation of prostaglandins within the uterus, synthesized via the type-2 cyclo-oxygenase enzyme (COX-2). These lead to remodelling of the fetal membranes and cervix and to stimulation of myometrial contractions. In the human, the principal source of prostaglandins is the amnion. Progesterone acts to promote myometrial quiescence, and in many species the onset of labour is preceded by withdrawal of progesterone. Humans show no systemic progesterone withdrawal, although biochemical changes within the uterus are similar to those in other species. A mutual negative interaction between the transcription factor nuclear factor (NF)-kappaB and the progesterone receptor (PR) has been reported. Using transient transfections and assays for transcriptional activation and promoter binding, we have shown that there is constitutive activity of NF-kappaB in amnion cells at the time of labour, and that COX-2 expression depends upon NF-kappaB. In cells obtained before labour, in which NF-kappaB activity is low, increasing the concentration of PR represses NF-kappaB dependent transcription, while stimulation with IL-1beta both increases NF-kappaB activity and represses PR activity. Our data suggest that human labour is associated with constitutive NF-kappaB activity within the amnion, which functions to increase the expression of COX-2 and appears to contribute to the 'functional progesterone withdrawal'.

Quantitative digital analysis of regional placental perfusion using power Doppler in placental abruption

PURPOSE

To apply digital imaging techniques to the quantification of placental vascularity using power Doppler.

MATERIALS AND METHODS

Regional placental blood flow was measured in a case of large placental abruption, shortly after presentation and 1 week later. Images were stored digitally and analysed using purpose-designed software (CQ Analysis) to extract and measure vascular energy information. The integrated color energy (ICE) was determined in the main body of placental tissue and in a cotyledon isolated by the retroplacental clot.

RESULTS

Initial assessment at 25 weeks showed only a small difference in integrated energy between normal placenta and the isolated cotyledon (ICE ratio 1.44, P < 0.04). One week later, perfusion in the isolated cotyledon had fallen both on qualitative and quantitative assessment (ICE ratio 3.98, P < 0.0001). This area subsequently became devascularized.

CONCLUSION

Placental perfusion may be quantified using digital power Doppler analysis. Further studies are indicated to evaluate its role in assessing regional and/or global placental perfusion as well as fetal organ perfusion.

NF-kappaB and AP-1 are required for cyclo-oxygenase 2 gene expression in amnion epithelial cell line (WISH)

Prostaglandins are known to play an important role in human labour and are used clinically to induce labour onset. Cytokines, e.g. interleukin 1 beta (IL-1beta), are up-regulated in the amniotic fluid late in gestation and can increase prostaglandin production through the expression of cyclo-oxygenase 2 (COX-2), the prostaglandin synthetic isoform involved in human labour. We demonstrate in immortalized amnion epithelial (WISH) cells, that IL-1beta causes increased transcription of the COX-2 gene. Luciferase reporter constructs with site-directed mutagenesis of the two NF-kappaB sites and an AP-1 site in the COX-2 promoter showed reduced expression of luciferase in transient transfection studies. This suggests that the binding of transcription factors to these sites is essential for the regulation of COX-2 transcription in IL-1beta-treated WISH cells.

Interleukin 8 expression in human myometrium: changes in relation to labor onset and with gestational age

PROBLEM

Preterm labor remains the major cause of perinatal mortality and morbidity in normally formed babies. The mechanisms involved in the onset of preterm labor are poorly understood, mainly because the mechanisms initiating term labor remain ill-defined.

METHOD OF STUDY

Human myometrial samples were collected at cesarean delivery from preterm (26-36 weeks gestation) and term (37-41 weeks) women. Women at term were either non-laboring or laboring. The expressions of interleukin-8 (IL-8) mRNA and protein were measured by reverse transcriptase-polymerase chain reaction and enzyme-linked immunosorbent assay, respectively.

RESULTS

The expression of both IL-8 mRNA and protein significantly increased in the term laboring group, compared with either the term non-laboring or preterm groups. Levels of IL-8 expression did not alter with advancing gestational age.

CONCLUSIONS

The increased expression of IL-8 in laboring myometria at term supports the hypothesis that up-regulation of IL-8 has a role in the initiation of labor in association with an influx of neutrophils and the release of their collagenolytic enzymes into uterine tissues.

High sensitivity of fetal DNA in plasma compared to serum and nucleated cells using unnested PCR in maternal blood

DNA analysis of blood is conventionally performed on cells - plasma and serum are discarded. Free DNA has been demonstrated in serum in cancer and autoimmune disorders and in pregnancy. We investigated possible noninvasive prenatal diagnosis using fetal DNA from maternal plasma and serum in pregnancy. Fetal gender was determined by PCR on DNA from maternal venous blood, serum and plasma of 65 women by boiling with or without phenol/chloroform extraction. When sensitivities were compared for plasma, additional phenol/chloroform extraction proved more sensitive than boiling alone (89 vs. 50%), the observed difference was 50% (CI 19 to 81%). Extracted plasma amplified better than extracted serum (89 vs. 46%), the observed difference being 44% (CI 22 to 66%). In contrast, fetal gender could not reliably be determined from DNA extracted from maternal nucleated blood cells. The size of plasma and serum DNA at 15-17 weeks of gestation was >1,500 bp. This work confirms the presence of fetal DNA in maternal plasma and serum which may be applicable to noninvasive prenatal diagnosis of paternally derived DNA sequences. We conclude that optimal sensitivity requires two methods of DNA extraction and that the use of plasma is preferred to that of serum.

The regulation of prostaglandin output from term intact fetal membranes by anti-inflammatory cytokines

Prostaglandins are some of the main mediators which control parturition, and their production by intrauterine tissues can be up-regulated by pro-inflammatory cytokines. Anti-inflammatory cytokines may oppose these effects, and in this study we have investigated how two such cytokines affected fetal membrane function. Interleukin-10 (IL-10) inhibited the output of prostaglandin E2 (PGE2) from intact fetal membranes under basal and lipopolysaccharide (LPS)-stimulated conditions, and there was a parallel decrease in the expression of mRNA for COX-2. IL-10 also inhibited the production of interleukin-1beta (IL-1beta) and the expression of mRNA for IL-1beta, indicating that this cytokine has a broad anti-inflammatory effect. Transforming growth factor-beta1 (TGF-beta1), which is generally considered to be anti-inflammatory had opposite effects on PGE2 production, in that it increased the output of PGE2 for up to 8 hr. TGF-beta1 increased levels of type-2 cyclo-oxygenase (COX-2) and cytosolic phospholipase A2 (cPLA2) protein, and also activated the cPLA2 enzyme present; the profile of effects is similar to that of the pro-inflammatory cytokine IL-1beta, and was not expected. Combinations of TGF-beta1 with IL-1beta also increased PGE2 output and caused appropriate changes in prostaglandin pathway enzymes, whereas TGF-beta1 and IL-1alpha had more limited effects. Further studies are needed to establish the physiological significance of these findings, but TGF-beta1 does not seem to act as an inhibitory cytokine in intact fetal membranes at term.

The roles of the cyclo-oxygenases types one and two in prostaglandin synthesis in human fetal membranes at term

The aim of this study was to determine the relative contributions of cyclo-oxygenase (COX) types 1 and 2 to prostaglandin synthesis at term.

METHODS

Fetal membranes were collected from 6 pregnancies after elective caesarean section at term, prior to labour. The presence of COX-1 and COX-2 protein was determined using Western analysis. The relative contributions of the two isoforms of COX to prostaglandin synthesis were determined by incubation of fetal membrane discs with either a COX-2 selective inhibitor, SC236, or a COX-1 selective inhibitor, SC560, and measurement of prostaglandin release during 24 h using enzyme-linked immuno-sorbent assay (ELISA).

RESULTS

Both COX-1 and COX-2 protein were demonstrated in amnion and chorion-decidua. The COX-2 selective inhibitor, SC-236, significantly reduced prostaglandin synthesis, both in its COX-2 specific and higher, non-specific concentration ranges. The COX-1 selective inhibitor, SC-560, had no effect upon prostaglandin synthesis in its COX-1 specific concentration range, but did significantly reduce prostaglandin synthesis at higher, non-selective concentrations.

CONCLUSIONS

Fetal membranes contain both COX-1 and COX-2 at term, but only COX-2 contributes towards prostaglandin synthesis. COX-2 selective NSAI drugs will be as effective as non-selective agents in inhibition of fetal membrane prostaglandin synthesis and may represent a new strategy for tocolysis.

Expression of nitric oxide synthase isoforms in pregnant human myometrium

1. Endogenous nitric oxide has been proposed to play a role in the control of myometrial contractility in pregnancy. In this study, the expression, localisation and regulation of nitric oxide synthase (NOS) isoforms have been examined in human pregnant myometrium and cultured human myometrial smooth muscle cells, by immunoblotting, immunohistochemistry and reverse transcription-polymerase chain reaction. 2. Immunoblotting of extracts from freshly isolated myometrial tissue, affinity-enriched for NOS proteins by precipitation with ADP-sepharose, revealed expression of endothelial NOS (eNOS or NOS3) in tissues from preterm, term non-labour and active labour at term. Inducible NOS (iNOS or NOS2) and neuronal NOS (nNOS or NOS1) proteins were not detected at any stage of pregnancy. 3. Immunohistochemical detection showed that expression of eNOS protein was restricted to the endothelium of the myometrial vasculature, with no staining detected in myometrial smooth muscle cells. 4. Messenger RNA for all three NOS isoforms was detected, although iNOS and nNOS mRNAs were detectable only with high cycle number, implying a low copy number. 5. NOS isoforms were not detectable in human myometrial smooth muscle cells cultured from term non-labour pregnancies. Cytokine stimulation of cultured myometrial cells did not induce iNOS expression or nitrite accumulation in the culture medium, although both iNOS protein and nitrite release were detected in the human pulmonary epithelial cell line A549. 6. Levels of eNOS protein and of NOS mRNA expression were not correlated with gestational stage, suggesting that endogenously produced NO is not likely to be a modulator of myometrial tone during human pregnancy.

Expression of cyclo-oxygenase types-1 and -2 in human myometrium throughout pregnancy

Human labour is associated with increased prostaglandin synthesis within the uterus. The aim of this study was to examine the expression of the two isoforms of the central prostaglandin synthetic enzyme, cyclo-oxygenase (COX-1 and COX-2) in human myometrium throughout pregnancy and to test the hypothesis that COX in the myometrium may play a role in labour onset. Expression of COX-1 and COX-2 at the mRNA level was analysed using reverse transcriptase-polymerase chain reaction (RT-PCR) and at the protein level using Western blotting. No significant changes of COX-1 RNA or protein expression were observed either with gestational age or labour. COX-2 mRNA and protein expression increased at term with significant up-regulation occurring prior to the onset of labour (P < 0.005). These data would suggest that up-regulation of COX-2, rather than COX-1, mediates increased prostaglandin synthesis in human myometrium at term. The increased COX-2 expression observed preceded labour onset, suggesting that COX-2 has a role in labour onset, rather than its presence merely a consequence of labour.

Expression of 5-lipoxygenase and 5-lipoxygenase-activating protein in human fetal membranes throughout pregnancy and at term

Lipoxygenase metabolites may be involved in human parturition. 5-lipoxygenase (5-LOX) catalyses the first steps in the synthesis of leukotrienes from arachidonic acid, and its activity is dependent on 5-LOX activating protein (FLAP). The expression of 5-LOX and FLAP were investigated in fetal membranes to determine whether there are changes with gestational age or at term with the onset of labour. No significant differences were found in the expression of 5-LOX or FLAP mRNA in the amnion at different gestational ages or at term. In the chorion-decidua, 5-LOX mRNA expression was significantly higher in the first trimester of pregnancy than in the second and third trimesters. At term, there was a significant increase in both 5-LOX mRNA and protein expression in the chorion-decidua in the time after labour, compared with the time before labour. The expression of FLAP mRNA was also significantly higher in the chorion-decidua in the first trimester of pregnancy compared with the third trimester, and at term in the time after labour compared with the time before labour. Expression of FLAP protein was not studied, as an antibody is not currently available. These results are consistent with a role for 5-LOX and FLAP in the control of parturition at term, and also suggest an involvement earlier in pregnancy.

The production of interleukin-1beta from human fetal membranes is not obligatory for increased prostaglandin output

Bacterial endotoxin increased the expression of mRNA (maximal after 4 hr) for interleukin-1beta (IL-1beta) and the release of mature protein from intact human fetal membranes. In contrast, the change in expression of mRNA for type 2 cyclo-oxygenase (COX-2) was biphasic, with peaks after 0.5-1 hr and after 8 hr of culture. An antibody to IL-1beta was without effect after 4 hr of culture, inhibited endotoxin-stimulated prostaglandin E2 (PGE2) production after 8 hr of culture, and caused a parallel decrease in the expression of mRNA for COX-2. We conclude that endotoxin induced the expression of COX-2 through IL-1beta-independent and IL-1beta-dependent mechanisms, and these differences are time dependent. Corticotrophin-releasing hormone (CRH) or platelet-activating factor (PAF) also increased the expression of mRNA for IL-1beta and the release of IL-1beta from some, but not all, fetal membranes. The antibody to IL-1beta did not affect CRH-stimulated or PAF-stimulated PGE2 production or COX-2 expression. We conclude that CRH and PAF can induce the expression of IL-1beta, but this is not obligatory for increased PGE2 release, and the effect of these stimuli on COX-2 expression is a direct, IL-1beta-independent effect.

An inhibitor of type-1 cyclo-oxygenase in tissues from human pregnancy

BACKGROUND

Previous work has shown that first trimester human decidua contains a protein which directly inhibits the activity of type-1 cyclo-oxygenase (COX-1).

METHODS

Activity assays for cyclo-oxygenase types I and II were developed. Cell cytosol was prepared from a number of different sources: human placenta and decidua (first and third trimester), two placental cell-lines (BeWo and TCL-1), an endometrial stromal cell-line and K562 erythroleukemia cells. The effects of all cytosols on activity of type I cyclo-oxygenase, and of cytosols from BeWo choriocarcinoma and decidual cells on type II enzyme, were tested.

RESULTS

Cytosols from first trimester human placenta, two placental cell-lines, an endometrial stromal cell-line and K562 erythroleukemia cells all inhibited the type I enzyme. The inhibitor protein could not be detected in third trimester human decidual cells after labor, and was present only at very low levels in third trimester decidua prior to the onset of labor. Cytosols from BeWo and decidual cells had no effect on the activity of the type-2 cyclo-oxygenase enzyme.

CONCLUSIONS

The inhibitor of type I cyclo-oxygenase was not specific to pregnancy-related tissues, and may be a general regulator of this enzyme. Lower levels of inhibitor were present at term, but the physiological significance of this is unclear. The cytosolic inhibitor appears to be specific to the type I enzyme.

Corticotrophin-releasing hormone and platelet-activating factor induce transcription of the type-2 cyclo-oxygenase gene in human fetal membranes

Corticotrophin-releasing hormone (CRH) and platelet-activating factor (PAF) are considered to be involved in the physiological processes of human labour. Both may have dual effects, directly regulating myometrial contractility and fetal membrane prostaglandin production. During this study, we investigated the mechanisms through which CRH and PAF exert their latter effect. CRH and PAF increased prostaglandin production from intact fetal membrane discs, with a maximum stimulation after 8 h of culture. Reverse transcription-polymerase chain reaction (RT-PCR) analyses using primers specific for type-2 cyclo-oxygenase (COX-2) showed that CRH and PAF increased the transcription of COX-2 mRNA two-fold after 8 h culture. These data indicate that the increased fetal membrane prostaglandin production in response to CRH or PAF may involve the induction of COX-2.

Recent advances in the therapeutic management of preterm labour

Preterm labour and delivery pose an increasing problem to the obstetrician. Improvements in tocolysis with the recent introduction of new therapeutic targeting strategies, and a reappraisal of the safety and relative efficacy of some older compounds, have led to a tendency away from prescribing beta-sympathomimetic agents. Infection prophylaxis and promotion of fetal lung maturity are deemed advantageous, but treatment protocols have not been clarified. This review examines the important publications of the past year in these areas.