Biochemical changes in the cervical tissue of rabbit induced by interleukin-8, interleukin-1beta, dehydroepiandrosterone sulphate and prostaglandin E2: a comparative study

Randomized control trial comparing hygroscopic cervical dilators to cervical ripening balloon for outpatient cervical ripening

BACKGROUND

Outpatient term preinduction cervical ripening with mechanical agents has been associated with reduced length of stay, decreased cesarean delivery rates, low maternal and neonatal complications, and increased incidence of vaginal delivery within 24 hours.

OBJECTIVE

This study aimed to demonstrate equivalent efficacy between synthetic hygroscopic dilators and the single-balloon catheter for outpatient cervical ripening.

STUDY DESIGN

This randomized control equivalence trial compared synthetic hygroscopic dilators with the 30-mL silicone single-balloon catheter in primiparous and multiparous patients undergoing labor induction. The primary outcome was time from admission to delivery, with a prespecified 3-hour margin of equivalence. The secondary objectives were patient outcomes and perspectives.

RESULTS

Between March 1, 2019, and May 31, 2021, 1605 patients met the screening criteria, and 174 patients completed the study. The mean admission-to-delivery time was equivalent at 18.01 hours for the dilator group vs 17.55 hours for the balloon group (P=.04). The cesarean delivery rate of primiparous patients was similar at 28.1% with dilators vs 29.7% with the balloon. The groups had similar median cervical dilation and pain scores on insertion and admission. Overall patient satisfaction was high, 92.8% with dilators vs 96.2% with the balloon. The balloon group had significantly higher rates of early admission and device expulsion.

CONCLUSION

Although the enrollment goal was not met, our study suggests that synthetic hygroscopic dilators and the single-balloon catheter for outpatient cervical ripening are both efficacious with similar time from admission to delivery, pain scores, and patient satisfaction with the procedure.

Raspberry Leaves and Extracts-Molecular Mechanism of Action and Its Effectiveness on Human Cervical Ripening and the Induction of Labor

The gestational period is an incredibly stressful time for a pregnant woman. Pregnant patients constantly seek effective and reliable compounds in order to achieve a healthy labor. Nowadays, increasing numbers of women use herbal preparations and supplements during pregnancy. One of the most popular and most frequently chosen herbs during pregnancy is the raspberry leaf (Rubus idaeus). Raspberry extracts are allegedly associated with a positive effect on childbirth through the induction of uterine contractions, acceleration of the cervical ripening, and shortening of childbirth. The history of the consumption of raspberry leaves throughout pregnancy is vast. This review shows the current status of the use of raspberry leaves in pregnancy, emphasizing the effect on the cervix, and the safety profile of this herb. The majority of women apply raspberry leaves during pregnancy to induce and ease labor. However, it has not been possible to determine the exact effect of using raspberry extracts on the course of childbirth and the perinatal period. Additionally, it is unclear whether this herb has only positive effects. The currently available data indicate a weak effect of raspberry leaf extracts on labor induction and, at the same time, their possible negative impact on cervical ripening.

Results of Induction of Labor with Prostaglandins E1 and E2 (The RIPE Study): A Real-World Data Analysis of Obstetrical Effectiveness and Clinical Outcomes of Pharmacological Induction of Labor with Vaginal Inserts

Despite extensive knowledge of the mechanisms responsible for childbirth, the course of labor induction is often unpredictable. Therefore, labor induction protocols using prostaglandin analogs have been developed and tested to assess their effectiveness in labor induction unequivocally. A total of 402 women were collected into two groups-receiving vaginal Misoprostol or vaginal Dinoprostone for induction of labor (IOL). Then, the patients were compared in groups depending on the agent they received and their gestational age. Most patients delivered within 48 h, and most of these patients had vaginal parturition. Patients who received the Dinoprostone vaginal insert required statistically significantly more oxytocin administration than patients who received the Misoprostol vaginal insert. Patients who received the Misoprostol vaginal insert used anesthesia during labor statistically more often. Patients who received Misoprostol vaginal inserts had a statistically significantly shorter time to delivery than those with Dinoprostone vaginal inserts. The prevalence of hyperstimulation was similar in all groups and remained low. Vaginal Misoprostol-based IOL is characterized by a shortened time to delivery irrespective of the parturition type, and a lower need for oxytocin augmentation, but also by an increased demand for intrapartum analgesia administration. A vaginal Dinoprostone-based IOL protocol might be considered a more harmonious and desirable option in modern perinatal care.

Signaling Pathways Regulating Human Cervical Ripening in Preterm and Term Delivery

At the end of gestation, the cervical tissue changes profoundly. As a result of these changes, the uterine cervix becomes soft and vulnerable to dilation. The process occurring in the cervical tissue can be described as cervical ripening. The ripening is a process derivative of enzymatic breakdown and inflammatory response. Therefore, it is apparent that cervical remodeling is a derivative of the reactions mediated by multiple factors such as hormones, prostaglandins, nitric oxide, and inflammatory cytokines. However, despite the research carried out over the years, the cellular pathways responsible for regulating this process are still poorly understood. A comprehensive understanding of the entire process of cervical ripening seems crucial in the context of labor induction. Greater knowledge could provide us with the means to help women who suffer from dysfunctional labor. The overall objective of this review is to present the current understanding of cervical ripening in terms of molecular regulation and cell signaling.

Requirement for oxytocin augmentation in spontaneous parturition is associated with the maternal serum steroid hormones assessed by liquid chromatography coupled to the tandem mass spectrometry

AIM

The aim of research was to evaluate the maternal serum concentration of selected endogenous steroid hormones during spontaneous parturition at term and to determinate their association with the need for oxytocin augmentation.

METHODS

Blood of 108 healthy pregnant women whose parturition started with the regular spontaneous uterine contractions was drawn at the beginning of the labor. Liquid chromatography coupled to the tandem mass spectrometry device was utilized for measurement of sex hormone binding globulin, aldosterone, androstenedione, cortisol, cortisone, corticosterone, dehydroepiandrosterone, dehydroepiandrosteron sulphate, 17-hydroxyprogesterone, progesterone, and testosterone. Mann-Whitney U test, chi-square test, univariate and multivariate logistic regression, and receiver operating characteristic (ROC) analysis were used for the data analysis.

RESULTS

Reference ranges of the selected hormones assessed by liquid chromatography coupled to the tandem mass spectrometry in maternal serum were established. Statistically significant differences in the serum concentration of corticosterone, dehydroepiandrosterone, and androstenedione between mothers requiring oxytocin augmentation and the rest of women having spontaneous parturition were found (p = 0.002, p = 0.008, and p = 0.04, respectively). Concentrations were lower in the group of mothers who required oxytocin infusion for progression of labor. ROC analysis showed that all the mothers with dehydroepiandrosterone serum concentration above 21.6 nmol/L have lower chance to use oxytocin infusion for the labor progression ( area under the curve (AUC)  = 0.649, sensitivity = 71.7%, specificity = 59.6%, p = 0.006).

CONCLUSION

This research provided reference ranges for the selected maternal serum steroid hormones at the beginning of parturition. Association of corticosterone, dehydroepiandrosterone, and androstenedione with the need for the oxytocin infusion usage has been established. Dehydroepiandrosterone could be potential predictor of oxytocin infusion augmentation for progression of the parturition.

Positive correlation between patency and mRNA levels for cyclooxygenase-2 and prostaglandin E synthase in the uterine cervix of bitches with pyometra

Factors involved in patency of uterine cervices in the bitch with pyometra remain to be clarified. This study examined relationship between patency and mRNA levels for inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)-1, COX-2 and prostaglandin E synthase (PGES) in the uterine cervix of bitches with pyometra. Cervical patency was measured by inserting the stainless steel rods with different diameter into cervical canals. Levels of mRNA expression were determined by semi-quantitative reverse transcription-polymerase chain reaction. The cervical patency was positively correlated with mRNA levels for COX-2 and PGES, but not those for iNOS and COX-1. The results suggest that gene expression of COX-2 and PGES may be involved in the regulation of patency in the uterine cervix of bitches with pyometra.

Androgens in pregnancy: roles in parturition

BACKGROUND

Understanding the physiology of pregnancy enables effective management of pregnancy complications that could otherwise be life threatening for both mother and fetus. A functional uterus (i) retains the fetus in utero during pregnancy without initiating stretch-induced contractions and (ii) is able to dilate the cervix and contract the myometrium at term to deliver the fetus. The onset of labour is associated with successful cervical remodelling and contraction of myometrium, arising from concomitant activation of uterine immune and endocrine systems. A large body of evidence suggests that actions of local steroid hormones may drive changes occurring in the uterine microenvironment at term. Although there have been a number of studies considering the potential role(s) played by progesterone and estrogen at the time of parturition, the bio-availability and effects of androgens during pregnancy have received less scrutiny. The aim of this review is to highlight potential roles of androgens in the biology of pregnancy and parturition.

METHODS

A review of published literature was performed to address (i) androgen concentrations, including biosynthesis and clearance, in maternal and fetal compartments throughout gestation, (ii) associations of androgen concentrations with adverse pregnancy outcomes, (iii) the role of androgens in the physiology of cervical remodelling and finally (iv) the role of androgens in the physiology of myometrial function including any impact on contractility.

RESULTS

Some, but not all, androgens increase throughout gestation in maternal circulation. The effects of this increase are not fully understood; however, evidence suggests that increased androgens might regulate key processes during pregnancy and parturition. For example, androgens are believed to be critical for cervical remodelling at term, in particular cervical ripening, via regulation of cervical collagen fibril organization. Additionally, a number of studies highlight potential roles for androgens in myometrial relaxation via non-genomic, AR-independent pathways critical for the pregnancy reaching term. Understanding of the molecular events leading to myometrial relaxation is an important step towards development of novel targeted tocolytic drugs.

CONCLUSIONS

The increase in androgen levels throughout gestation is likely to be important for establishment and maintenance of pregnancy and initiation of parturition. Further investigation of the underlying mechanisms of androgen action on cervical remodelling and myometrial contractility is needed. The insights gained may facilitate the development of new therapeutic approaches to manage pregnancy complications such as preterm birth.

Forkhead box O1 (FOXO1) in pregnant human myometrial cells: a role as a pro-inflammatory mediator in human parturition

Prematurity is the most important complication contributing to neonatal morbidity and mortality. It is the untimely activation of the terminal events of human parturition that lead to preterm birth, with inflammation playing a driving role in initiating uterine contractions. The purpose of this study was to investigate the role of Forkhead box O1 (FOXO1), a pro-inflammatory modulator, during human parturition. FOXO1 mRNA expression was quantified using qRT-PCR, and protein expression using Western blotting in myometrial biopsies from pregnant non-labouring and labouring women at term. In addition, the effect of FOXO1 knockdown in human myometrial cells on IL-β-stimulated expression of pro-inflammatory mediators was investigated. Levels of FOXO1, at both the gene and protein levels, were higher in myometrium obtained from women in labour compared with samples taken from non-labouring women. FOXO1 deletion in myometrial cells attenuated the capacity of IL-1β to induce inflammatory gene expression. Specifically, FOXO1 knockdown significantly decreased IL-1β-induced IL-6 and IL-8 expression; production and COX-2 expression and subsequent prostaglandin (PGE2 and PGF2α) release; and MMP-9 mRNA expression and activity. In summary, this study demonstrates for the first time the potential role of FOXO1 inflammatory events of both physiological and pathological labour in human myometrium, and may provide a therapeutic target in the management of preterm labour.

Factors associated with patency of the uterine cervix in bitches with pyometra

This study examined factors involved in the patency of uterine cervices in the bitch with pyometra. The uterine cervices were obtained from the bitches with pyometra at the time of ovariohysterectomy. Cervical patency was measured by inserting the stainless steel rods with different diameter into cervical canals. Collagen concentration and collagenase activity (for type I collagen) in the tissue were determined and the number of neutrophils, which contain the enzymes related to collagen metabolism, and morphological changes in collagenous fibers were studied by histological examination. Levels of mRNA expressions for hormonal factors, estrogen receptor-α (ER-α), progesterone receptor (PR), relaxin (Rlx) and an attractant of neutrophils, interleukin-8 (IL-8), were determined by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). In the statistical analysis, the cervical patency positively correlated with the collagenase activity, and negative correlation was found between the cervical patency and collagen concentration. Histological examination indicated distinct positive correlation between the cervical patency and the number of neutrophils in the cervical stroma and that the collagenous fiber in the uterine cervix became thinner and degraded with increase of the cervical patency. Although there was no relationship between the cervical patency and the level of mRNA for ER-α, PR or Rlx, IL-8 mRNA level has significant positive correlation with the cervical patency and the number of neutrophils in the cervical stroma. These results suggest that the increased number of neutrophils in the uterine cervix, which could be related to the local expression of IL-8, may be involved in collagen degradation and connective tissue remodeling to increase cervical patency in the bitch with pyometra.

NFκB and AP-1 drive human myometrial IL8 expression

The uterine expression of the chemokine IL8 increases dramatically with the onset of labour both at term and preterm. The IL8 promoter contains binding sites for the transcription factors nuclear factor-kappa B (NFκB), activator protein-1 (AP-1), and CCAAT/enhancer-binding protein (CEBP). In this study we investigated the roles of these transcription factors in IL1B regulation of the IL8 gene in human myometrium. Using chromatin immune precipitation (ChIP) assay, we showed that each of NFκB, CEBP, and AP-1 binds to the IL8 promoter upon IL1B stimulation. To examine the relative importance of each site in IL8 gene expression, site-directed mutagenesis of each of these sites was performed. We found that the NFκB site was essential for basal and IL1B-stimulated gene expression. Mutation of the AP-1 site reduced both basal and IL1B-stimulated expression but to a lesser extent. Mutation of the CEBP site had no effect upon basal expression but eliminated the IL1B response. Small interfering RNA (siRNA) silencing of NFκB abolished the IL8 response to IL1B significantly; siRNA against AP-1 reduced it to a lesser extent whilst knockdown of CEBP enhanced the response. Our data confirms a central and essential role for NFκB in regulation of IL8 in human myometrium.

Does progesterone inhibit bacteria-stimulated interleukin-8 production by lower genital tract epithelial cells?

OBJECTIVE

Progesterone (P(4)) has been clinically shown to prevent the recurrence of preterm birth. The mechanism(s) of action is unclear, but may involve modulation of the immunologic inflammatory response of the lower genital tract. We evaluated the effects of P(4) on interleukin-8 (IL-8) production by vaginal and cervical epithelial cells stimulated with bacterial species that are commonly associated with preterm birth.

METHODS

Vaginal and endocervical epithelial cells were incubated with up to 10,000 ng/mL P(4) overnight and stimulated with heat-killed Escherichia coli, Gardnerella vaginalis, or Ureaplasma urealyticum. Concentrations of IL-8 in conditioned medium were quantified by ELISA and viability of the cell cultures was measured by the reduction of a tetrazolium salt.

RESULTS

E. coli, G. vaginalis and U. urealyticum-stimulated IL-8 production for both cell lines. P(4) inhibited basal and bacteria-stimulated IL-8 production for vaginal epithelial cells but enhanced IL-8 production by endocervical cells. P(4) reduced the number of viable cells for both cell lines.

CONCLUSIONS

P(4) inhibits IL-8 production by vaginal epithelial cells stimulated with pathogens associated with preterm birth, possibly by reducing the number of viable cells or by inhibiting their proliferation. Although P(4) also reduces proliferation of endocervical cells it also increases their production of IL-8.

PREMATURE CERVICAL CHANGE AND THE USE OF CERVICAL CERCLAGE

Preterm birth and its subsequent consequences continue to be a major challenge worldwide. In the United States in 2004, 12.5% of infants were born preterm, making the annual societal economic burden associated with preterm birth in excess of $26.2 billion (and this is a modest estimate). Spontaneous preterm birth accounts for about 75% of all preterm births; however, at earlier gestations iatrogenic preterm birth accounts for a greater proportion of all preterm births; at 27–28 weeks 50% are iatrogenic. The proportion of babies transferred to the neonatal unit is more than 90% for those born before 33 completed weeks of gestation compared with 31% at 36 weeks; delivery between 33 completed weeks and 36 completed weeks has a relatively low morbidity and mortality. Nonetheless, 1 in 3 children born preterm but beyond 32 weeks have educational and behavioural problems at the age of 7, with 1 in 4 children born between 32 and 35 weeks requiring support from non-teaching assistants at school. Although more than 40% of babies at 35 completed weeks show signs of maturity, some still need ventilation at 38 completed weeks. Almost one-fifth of all infants born at less than 32 weeks gestation do not survive the first year of life.

Regulation of hyaluronan synthases in mouse uterine cervix

We examined the expression pattern of hyaluronan synthase (HAS) mRNAs in the uterine cervix of pregnant mice. The expression levels of HAS-1 and -2 mRNAs peaked at delivery, whereas that of HAS-3 mRNA peaked on the 15th day of pregnancy. The regulation of HAS mRNA expression was examined in pregnant mouse uterine cervical fibroblasts. The expression of HAS-1, -2, and -3 mRNAs was significantly augmented by interleukin-1beta (IL-1beta). Progesterone significantly interfered with expression of HAS-1 and -2 mRNAs, but significantly increased the expression of HAS-3 mRNA. Low-molecular-weight hyaluronan significantly enhanced only the expression of HAS-1 mRNA. These results indicate that HAS in the uterine cervix is regulated in a complex manner by IL-1beta, progesterone, and low-molecular-weight hyaluronan, of which changes in the cervical tissue and serum closely participate in uterine cervical ripening and/or inflammation.

Is there a place for inhibition of cervical ripening in the management of preterm labour?

Although premature cervical ripening is one of the two major pathophysiological processes occurring in preterm labour, research has mostly focused on the development of tocolytic agents. Our goal in this study was to review the recent progress made in the understanding of cervical ripening physiology and to explore the molecules that could be targeted for the development of new pharmacological compounds capable of inhibiting this process and to further improve the management of preterm labour.

Effect of urinary trypsin inhibitor on potassium currents: fetus modulates membrane excitability by production of UTI

BACKGROUND

Amniotic fluid contains a significant level of urinary trypsin inhibitor (UTI). Previously, we reported that UTI inhibits calcium influx of myometrium and it is effective in preventing uterine contraction. This study examined the effects of UTI upon potassium channels, which is important for membrane excitability.

METHODS

Whole-cell patch-clamp recordings were performed in fibroblasts derived from human fetal skin. Potassium currents were recorded and the effects of exogenous UTI and/or cadmium determined.

RESULTS

Tetraethylammonium sensitive potassium currents were elicited by step or ramp stimulations at depolarized membrane potentials (over +30 mV). Administration of 1 micro M UTI significantly increased these potassium currents by 16.9%. When calcium channels were blocked by the administration of cadmium, UTI increased the rest of the potassium currents by 4.8%. This indicates that UTI increased calcium-dependent potassium currents by 94.8% but only increased voltage-dependent potassium currents by 4.8%.

CONCLUSIONS

Urinary trypsin inhibitor is a physiological substance of fetal origin that modulates calcium-dependent and voltage-dependent potassium channels. These data suggest that UTI is capable of regulating the membrane properties of the fetal and myometrial cells in contact with amniotic fluid.

Progesterone represses interleukin-8 and cyclo-oxygenase-2 in human lower segment fibroblast cells and amnion epithelial cells

Labor is preceded by cervical ripening through upregulation of interleukin (IL)-1beta, IL-8, and increased prostaglandin synthesis via inducible type 2 cyclooxygenase (COX-2). Progesterone maintains myometrial quiescence during pregnancy. In this study, we examined the effects of IL-1beta and progesterone on IL-8 and prostaglandin E2 (PGE2) synthesis and IL-8 and COX-2 mRNA and promoter activity in amnion cells and lower segment fibroblast (LSF) cells. In both cell types, progesterone had no effect on basal IL-8 or PGE2 synthesis. In LSF cells, IL-1beta significantly increased IL-8 and PGE2 synthesis and COX-2 and IL-8 mRNA expression, but progesterone significantly attenuated these effects. In prelabor amnion cells, IL-1beta also increased IL-8 and PGE2 synthesis and both COX-2 and IL-8 mRNA and promoter expression; however, progesterone significantly attenuated these effects on IL-8 and PGE2 synthesis and COX-2 expression. In postlabor amnion cells, IL-1beta increased IL-8 and PGE2 synthesis and COX-2 expression, but progesterone did not attenuate the effect of IL-1beta upon IL-8 synthesis. Progesterone repression of IL-8 and COX-2 in LSF cells suggests that IL-8 and COX-2 have similar regulatory mechanisms in LSF cells and that progesterone may play a role in maintenance of cervical competence. The lack of effect of progesterone on IL-8 in postlabor cells may be the result of downregulation of the progesterone receptor during labor.

Cytokine concentrations in the amniotic fluid during parturition at term: correlation to lower uterine segment values and to labor

BACKGROUND

In previous studies a significant increase in interleukin (IL)-6 and IL-8 concentrations in the lower uterine segment parallel to cervical dilatation at term could be found, however only a weak correlation to duration of labor was detected. This study compares amniotic fluid concentrations of interleukin (IL)-6 and IL-8 with those in the lower uterine segment, and the duration of labor.

METHODS

Amniotic fluid and lower uterine segment specimens were obtained from 29 patients during cesarean section at term. The patients were divided into groups according to cervical dilatation (< 2 cm, 2-3.9 cm, 4-6 cm, > 6 cm) and to labor (0 h, > 0-12 h, > 12 h). Interleukin-6 and IL-8 concentrations were determined by enzyme immunoassay.

RESULTS

Amniotic fluid IL-6 already increased at 2-3.9 cm (p = 0.02), while the steepest increase in IL-8 was observed at > 6 cm (p = 0.003). No correlation with lower uterine segment values was observed for either of the cytokines. However, the amniotic fluid IL-6 concentration correlated with labor (p = 0.0008).

CONCLUSION

The increase in the concentration of IL-6 in the amniotic fluid earlier than its increase in the lower uterine segment supports the hypothesis that IL-6 plays a crucial role for the promotion of labor in the first place, and afterwards for the biochemical degradation processes in the lower uterine segment. The fact that the greatest increase in IL-8 concentration occurs only at > 6 cm indicates that this chemotactic cytokine has only minor significance in the initiation of parturition by its concentration in the amniotic fluid.

Fertility following radical, conservative-surgical or medical treatment for tubal pregnancy: a population-based study

OBJECTIVE

To investigate the factors influencing the choice of treatment for ectopic pregnancy and to compare the subsequent fertility rates of radical, conservative-surgical or medical treatments.

DESIGN

Population-based study of 835 ectopic pregnancies registered between 1992 and 1996.

SETTING

Auvergne Ectopic Pregnancy Register (France).

SAMPLE

Four hundred and seventy-six women with tubal ectopic pregnancy who were not using contraception at the time of conception. Subsequent fertility was studied for the 291 women who attempted to conceive again.

METHODS

Comparison of reproductive outcomes according to ectopic pregnancy treatment. Cumulative fertility curves were calculated by the Kaplan-Meier estimator and compared by log rank test for univariate analysis and by Cox regression to take into account confounding variables.

MAIN OUTCOME MEASURE

Recurrence and fertility rates after ectopic pregnancy.

RESULTS

The first treatment given was 'radical' for 178 women (37%), 'conservative-surgical' for 262 (55%), and 'medical' for 35 (8%). The treatment failed in 1% for radical treatment, 5% for conservative-surgical treatment, and 36% for medical treatment. The two-year cumulative rate of recurrence was 27% with no significant difference between treatments. For women with previous infertility factors (in particular diseased contralateral tube), the treatments differed significantly, with the rate of intrauterine pregnancy lower for radical treatment and higher for medical treatment than for conservative-surgical treatment. For women with no infertility factor, there was no significant difference between treatments.

CONCLUSIONS

These results should be confirmed in a controlled trial. The results of this study provide the elements necessary to plan such a trial.

Platelet-activating factor induces an imbalance between matrix metalloproteinase-1 and tissue inhibitor of metalloproteinases-1 expression in human uterine cervical fibroblasts

Platelet-activating factor (PAF) is involved in such reproductive processes as parturition. We investigated the effect of PAF on the expression of matrix metalloproteinase-1 (MMP-1) and that of tissue inhibitor of metalloproteinases-1 (TIMP-1) in human uterine cervical fibroblasts. Uterine cervical tissue was obtained from patients who underwent cesarean section at term. Collagenase-dispersed fibroblasts were cultured and used in the experiments. PAF receptor was identified in the uterine cervical fibroblasts by use of reverse transcription-polymerase chain reaction and Southern blot analysis. Northern blot analysis showed that PAF increased the expression of MMP-1 mRNA in a time-dependent manner, whereas expression of TIMP-1 mRNA was not affected by PAF. Concentration of MMP-1 protein in the PAF-treated culture media significantly exceeded that in control cultures. The PAF-induced production of MMP-1 protein was abolished by treatment with WEB 2170, a specific PAF receptor antagonist. Results suggest that PAF may accelerate collagenolysis in the human uterine cervix by inducing an imbalance in the activity between MMP-1 and TIMP-1, thus contributing to the cervical ripening during parturition.

The influence of prostaglandins on leukocyte-endothelium interactions in rabbit mesenteric venules

Contradictory results have been reported concerning the effects of prostaglandins (PGs) on leukocyte-endothelium interactions. Therefore, we investigated the in vivo effects of PGE1, PGE2, Iloprost (a stable PGI2-analogue), and also of a combination of these PGs on leukocyte rolling and FMLP-induced leukocyte adhesion in venules of rabbit mesentery. This preparation was used because of its low level of vasoactivity, eliminating hemodynamic effects on leukocyte-endothelium interactions. The mesentery was superfused with PGs or vehicle. After 30 min FMLP was added to the PG-solution for 15 min, whereupon the tissue was superfused with the PG-solution alone for another 30 min. Neither the PGs nor the cocktail influenced leukocyte rolling. During FMLP administration leukocyte adhesion increased and leukocyte rolling decreased; adhesion was highest in the presence of PGE2. The FMLP-induced decrease in leukocyte rolling was similar in all groups. After FMLP administration had been stopped the number of adherent cells almost returned to baseline and the level of leukocyte rolling increased, the baseline level being reached only in the presence of PGE2. In conclusion, these findings indicate that the effects of PGs on leukocyte-endothelium interactions are limited.

A preliminary study on the usefulness of huIL-8 in cervical relaxation of the ewe for artificial insemination and for embryo transfer

The efficacy of using human interleukin 8 (huIL-8) as an agent for inducing cervical relaxation in estrous and diestrous sheep was assessed in a small pilot study. Multiparous, estrus-synchronized ewes were treated for either 2 or 5 consecutive days with vaginal suppositories with or without 5 micrograms cytokine. Cervical penetration with an insemination instrument was then assessed in vivo. After euthanasia, physical, histological and enzymological properties of the cervix were examined. Treatment of diestrous sheep with huIL-8 did not result in recruitment of neutrophils into the cervix. Treatment of estrous sheep with huIL-8 usually led to neutrophil recruitment to the cervix and to either full or partial penetration of the cervix. However, some animals receiving placebo treatment had neutrophil infiltration of both the vagina and cervix and, in one of these, partial penetration of the cervix was also achieved. Thus, treatment with IL-8 as the sole agent in the vaginal suppository was not sufficient to relax the cervix of the nonpregnant ewe in this study.

Pro-inflammatory cytokines induce expression of matrix-metabolizing enzymes in human cervical smooth muscle cells

The process of cervical ripening has been likened to an inflammatory reaction associated with the catabolism of cervical extracellular matrix by enzymes released from infiltrating leukocytes. We hypothesized that smooth muscle cells in the cervix also participate in this process and that pro-inflammatory cytokines act on cervical smooth muscle cells (CSMC) to provoke the expression of matrix-degrading enzymes. We treated primary cultures of human CSMC with tumor necrosis factor-alpha (TNF-alpha) and examined expression of the elastinolytic enzyme, cathepsin S, the collagen metabolizing matrix metalloproteinases (MMP)-1, -3, -9, and the tissue inhibitor of metalloproteinase (TIMP)-1 and -2. A time course analysis revealed that 10 ng/ml of TNF-alpha induced cathepsin S, MMP-1, -3, and -9 mRNA expression with the maximal response observed after 24-48 hours. TNF-alpha induced cathepsin S, MMP-1, -3, and -9 mRNA expression in a dose-dependent manner: the maximal effect was observed at a concentration of 10 ng/ml, with appreciable increases observed at concentrations of 0.1 to 1.0 ng/ml. In contrast, TIMP-1 and -2 mRNAs were not significantly increased by TNF-alpha treatment. Interleukin-1beta produced a pattern of gene expression in the CSMC similar to that observed following TNF-alpha treatment. Western blot analysis and zymography confirmed the induction of proMMP-1, -3, and -9 in response to TNF-alpha, but MMP-2 immunoreactivity and zymographic activity were unaffected. TNF-alpha increased secretion of procathepsin S, but did not affect TIMP-1 and reduced TIMP-2 production. We conclude that CSMC are targets of pro-inflammatory cytokines, which induce a repertoire of enzymes capable of degrading the cervical extracellular matrix. The induction of these enzymes may facilitate the normal ripening of the cervix at term and participate in the premature cervical changes associated with preterm labor.

Changes in the cervical extracellular matrix during pregnancy and parturition

The key function of the uterine cervix to maintain pregnancy is biochemically characterized by an increased synthesis of proteins (e.g., collagen), proteoglycans, and glycoproteins (e.g., fibronectin) as well as by defined interactions between these components of the extracellular matrix. In contrast to the slow phase of the cervical ripening process in late pregnancy, cervical dilatation during parturition requires the rapid production and action of catabolic enzymes leading mainly to collagen degradation and changes in its architecture but also to degradation of other fundamental matrix proteins. Evidence suggests that an increased production of TNF-alpha and IL-1 beta, e.g., induces a rise in the expression of endothelial adhesion molecules with subsequent extravasation of neutrophils into the cervical stroma and that the chemotaxis and degranulation of these cells is triggered by an increased concentration of IL-8. Rising concentrations of hyaluronan at this time have been considered as potent inducers of IL-1 beta and TNF-alpha synthesis by various leukocyte populations. The increase in IL-6 synthesis stimulates prostaglandin and leukotriene production causing dilatation of cervical vessels and further promoting the extravasation of leukocytes. The proteases released after degranulation of neutrophils encounter an already destabilized collagenous fiber network. Since a sustained action of proteases may lead to severe tissue damage, this process is strictly limited in time and is controlled by increasing concentrations of tissue inhibitors of protease in the lower uterine segment immediately after delivery. The clinical consequences of this basic research is to develop new concepts in a more causal treatment of cervical pathology during pregnancy and parturition.

The importance of extracellular matrix in the induction of preterm delivery

Evidence suggests that in the lower uterine segment at term an increased production of tumor necrosis factor (TNF) alpha and interleukin (IL)-1 beta induces an increase in the expression of adhesion molecules by the endothelium. The expression of endothelial-leukocyte adhesion molecule-1 and vascular cell adhesion molecule-1 were found to increase from a cervical dilatation of 2-3 cm and reaches a maximum at cervical dilatation of more than 6 cm. Increased adhesiveness of the endothelium leads to extravasation of neutrophils into the cervical stroma. The chemotaxis and degranulation of these cells is triggered by a rise in the concentration of IL-8 found in the lower uterine segment when cervical dilatation progresses. A significant increase in stroma invasion by neutrophils with progressive cervical dilatation was observed. This finding coincides with a rise in the granulocytic matrix metalloproteinases (MMP)-8 and MMP-9 concentrations up to complete cervical dilatation. We found similar patterns of cytokine concentrations in the lower uterine segment of patients with preterm delivery: at 2-3 cm dilatation the concentrations of IL-1 beta, IL-6- und IL-8 were significantly higher than at less than 2 cm. Concomitantly, we also found an increase in MMP-8, MMP-9 and tissue inhibitor of metalloproteinases-1 concentrations from less than 2 cm to 2-3 cm cervical dilatation. These findings suggest that the changes in the lower uterine segment during preterm parturition seem to be similar to those at term and both resemble an inflammatory process.

Sensitivity of the early luteal phase ovine cervix to prostaglandin E2 (PGE2) and expression of EP3 receptor mRNA

The effects and mechanism of action of prostaglandin E2 (PGE2) on the ovine cervix are largely unknown in the luteal phase. In these studies we have shown that low levels of EP3-receptor (EP3R) mRNA are present in the ovine cervix and that the PGE2 induces activation of polymorphonuclear leukocytes in the ovine cervix on day 6 of the oestrous cycle. It is possible, therefore, that PGE2 acts on the ovine cervix through coupling to EP3 receptors.