Aurelija Dubicke

Pro-inflammatory and anti-inflammatory cytokines in human preterm and term cervical ripening

Cervical ripening is necessary for successful delivery. Since cytokines are believed to be involved in this process, the aim of this study was to investigate possible changes in the mRNA and protein expression of pro-inflammatory cytokines (interleukin (IL)-1alpha, IL-1beta, IL-12, IL-18) and anti-inflammatory cytokines (IL-4, IL-10, IL-13) in the human cervix during pregnancy, term and preterm labor. Cervical biopsies were taken from 59 women: 21 at preterm labor, 24 at term labor, 10 at term not in labor and 4 from non-pregnant women. mRNA was analyzed with real-time RT-PCR and protein expression and/or secretion with immunohistochemistry and ELISA. There was an upregulation of mRNA for IL-10, IL-13, IL-1alpha and IL-1beta in the laboring groups, while mRNA for IL-12 and IL-18 was downregulated. IL-4 mRNA was detected more frequently, while IL-12 mRNA expression was lower, in the preterm labor group than in the term labor group. The protein levels of IL-4 and IL-12 were lower and IL-18 tended to be higher in the labor groups, while IL-10 protein levels were unaffected by labor. IL-4 protein levels were significantly higher in the preterm subgroup with bacterial infection than in the non-infected group. IL-10 had higher expression in squamous epithelium at preterm labor than at term. In conclusion, the major changes in pro-inflammatory and anti-inflammatory cytokine mRNA and protein expression in cervix occur during the labor process irrespective of the length of gestation. Our results indicate that dysregulation of anti-inflammatory cytokines in the human cervix could be involved in the pathogenesis of preterm labor.

Different secretion patterns of matrix metalloproteinases and IL-8 and effect of corticotropin-releasing hormone in preterm and term cervical fibroblasts

The aims of the present study were to compare the levels of mRNA and protein expression of matrix metalloproteinase (MMP)-1, -3, -8 and -9 in human cervical tissue in preterm and term labor as well as not in labor and to determine if corticotropin-releasing hormone (CRH) has an effect on MMP-1, -3 and interleukin (IL)-8 secretion in both preterm and term cervical fibroblasts. Cervical biopsies were taken from 60 women: 18 at preterm labor, 7 at preterm not in labor, 18 at term labor and 17 at term not in labor. ELISA and Immulite were used for protein and real-time RT–PCR for mRNA analysis. Cervical fibroblast cultures were incubated for 18 h with different CRH concentrations (10−13–10−6 M). The mRNA expression of MMP-1, -3 and -9 was higher in laboring groups compared with term not in labor. Protein levels of MMP-8 and -9 were higher in term in labor group compared with non-laboring groups. There were no significant differences in mRNA and protein expression between the preterm and respective term control groups. CRH significantly increased secretion of IL-8 in preterm and term cervical fibroblasts compared with controls. The secretion of IL-8 and MMP-1 was significantly higher and MMP-3 secretion lower in preterm cervical fibroblasts. In conclusion, cervical ripening at preterm seems to be a similar inflammatory process as at term with CRH involved. However, preterm and term cervical fibroblasts might have different phenotypes based on different secretion patterns of IL-8, MMP-1 and MMP-3.

High-mobility group box protein 1 and its signalling receptors in human preterm and term cervix

The objective of this study was to identify possible changes in mRNA and protein expression of high-mobility group box protein 1 (HMGB1) and its suggested receptors - receptor for advanced glycation end-products (RAGE) and Toll-like receptor 2 (TLR2) and TLR4 - in human cervix during pregnancy, term and preterm labor. Cervical biopsies were taken from 58 women: 20 at preterm labor, 24 at term labor, 10 at term not in labor and 4 from non-pregnant women. Real-time RT-PCR was used to quantify mRNA expression, and immunohistochemistry and ELISA for protein analysis. HMGB1, RAGE, TLR2 and TLR4 proteins were localized and their mRNA expression was detected in the cervix. There was more extranuclear HMGB1 in the cervical epithelium and stroma in preterm and term labor compared to the term not in labor. TLR2 mRNA expression was upregulated 5-fold in term labor and 3-fold in preterm labor compared to term not in labor and non-pregnant controls. There was lower expression of TLR2 and TLR4 mRNAs in preterm labor compared to term. Lower mRNA expression of HMGB1 was found in the subgroup with preterm premature rupture of membranes than in the rest of the preterm group, where levels were significantly higher than in term labor. In conclusion, extranuclear expression of HMGB1 during labor suggests a possible role of HMGB1 during the process of cervical ripening. Changes in expression of mRNAs encoding HMGB1, TLR2 and TLR4 in preterm labor suggest differences in the mechanism of cervical ripening at preterm and term delivery.

Low molecular weight heparin stimulates myometrial contractility and cervical remodeling in vitro

Objectives. The low molecular weight heparin, Dalteparin, shortens human labor time. The aim of this study was to investigate if the mechanism behind this effect involves myometrial contractility and cervical ripening and if the anticoagulative activity is necessary for its effect. Design. Experimental in vitro study. Setting. Lund University and Karolinska Institute, Sweden. Methods. The effect of low molecular weight heparins with or without anticoagulative properties on myometrial contractility was measured in vitro on smooth muscle strips from biopsies obtained at elective cesarean sections. The effects on cervical ripening were assessed in cervical fibroblasts cultured from explants of cervical biopsies obtained at delivery. Main outcome measures. Mean force and number of contractions in uterine smooth muscle strips and interleukin‐8 (IL‐8) secretion in cervical fibroblasts. Results. Myometrial smooth muscle strips pretreated with low molecular weight heparins showed increased contractile activity compared to untreated smooth muscle strips. Secretion of IL‐8 from cultured cervical fibroblasts was significantly increased after treatment with low molecular weight heparin. Both these effects were independent of anticoagulative activity of the low molecular weight heparin. Conclusions. A possible underlying mechanism for the shortened labor time after low molecular weight heparin treatment is enhanced myometrial contractility and an increased IL‐8 secretion in cervical fibroblast, mimicking the final cervical ripening in vivo. Our data support the notion that anticoagulant activity is not required to promote labor.

Does low molecular weight heparin shorten term labor

Dalteparin, a low molecular weight heparin (LMWH), is given to pregnant women with thrombotic disorders. Clinical observations together with the documented changes of heparan sulfate proteoglycans in normal and protracted labor fostered the idea that LMWH shortens delivery time. Labor time was retrospectively determined among nulliparous pregnant women treated with dalteparin because of previous venous thromboembolism (VTE), thrombophilia or acute VTE during current pregnancy. Their labor time was compared to matched untreated controls. The proportion of instrumental deliveries and neonatal outcome was also compared. The dalteparin‐treated group showed a significantly (30%) shorter labor time compared to matched controls. Total instrumental deliveries were the same in the two groups but operative intervention due to protracted labor was significantly less common in dalteparin‐treated women. There was no difference in neonatal outcome. Dalteparin most likely shortens parturition time and may decrease the number of operative interventions due to protracted labor.

Negative Emotions and Cytokines in Maternal and Cord Serum at Preterm Birth

Problem  This study investigates whether affectivity differs between mothers delivering preterm and term and whether maternal and umbilical cord serum cytokines differ between these groups. Further, whether there are associations between mothers’ emotions and maternal and cord cytokines at preterm and term birth.

Differences in heparan sulfate production in cervical fibroblast cultures from women undergoing term and preterm delivery

Objective. An extensive remodeling of the human cervical connective tissue occurs throughout pregnancy, with a decrease in the total concentration of collagen and proteoglycans. We hypothesized that the profound changes in proteoglycan production in the cervix would be seen in corresponding cervical fibroblasts as well. Methods. Cervical biopsies were obtained from five non‐pregnant women, five women undergoing elective Cesarean section, six women directly after spontaneous term parturition and four directly after spontaneous preterm parturition. By explant technique, fibroblasts were cultured from the biopsies. Subcultures of the primary fibroblasts were treated with antibodies to heparan sulfate proteoglycans and labeled with radioactive sulfate. The labeled proteoglycans were purified by ion‐exchange chromatography and separated by gel electrophoresis. Results. Proteoglycan production was reduced by 50% in fibroblasts obtained from term and preterm women. In comparison to equivalent control cultures from non‐pregnant women, this decline was significant. Production of the proteoglycans biglycan and perlecan was similar in term partal and preterm partal cell cultures. Biglycan production was significantly reduced (by 40%) and perlecan production was significantly induced (by 60%) compared to control cultures. Fibroblast cultures established from women with preterm delivery had significantly higher production of heparan sulfate proteoglycans than those obtained from non‐pregnant donors. Heparan sulfate proteoglycans were localized to cell membranes and intracellular compartments. Conclusions. The changes in proteoglycan production in the human pregnant cervix can also be seen in corresponding cervical fibroblasts. Term partal and preterm partal cells differed from their non‐pregnant counterpart, which suggests a role for proteoglycans in cervical ripening.

The preterm cervix reveals a transcriptomic signature in the presence of premature prelabor rupture of membranes

BACKGROUND: Premature prelabor rupture of fetal membranes accounts for 30% of all premature births and is associated with detrimental long‐term infant outcomes. Premature cervical remodeling, facilitated by matrix metalloproteinases, may trigger rupture at the zone of the fetal membranes overlying the cervix. The similarities and differences underlying cervical remodeling in premature prelabor rupture of fetal membranes and spontaneous preterm labor with intact membranes are unexplored. OBJECTIVES: We aimed to perform the first transcriptomic assessment of the preterm human cervix to identify differences between premature prelabor rupture of fetal membranes and preterm labor with intact membranes and to compare the enzymatic activities of matrix metalloproteinases‐2 and ‐9 between premature prelabor rupture of fetal membranes and preterm labor with intact membranes. STUDY DESIGN: Cervical biopsies were collected following preterm labor with intact membranes (n = 6) and premature prelabor rupture of fetal membranes (n = 5). Biopsies were also collected from reference groups at term labor (n = 12) or term not labor (n = 5). The Illumina HT‐12 version 4.0 BeadChips microarray was utilized, and a novel network graph approach determined the specificity of changes between premature prelabor rupture of fetal membranes and preterm labor with intact membranes. Quantitative reverse transcription–polymerase chain reaction and Western blotting confirmed the microarray findings. Immunofluorescence was used for localization studies and gelatin zymography to assess matrix metalloproteinase activity. RESULTS: PML‐RARA‐regulated adapter molecule 1, FYVE‐RhoGEF and PH domain‐containing protein 3 and carcinoembryonic antigen‐ralated cell adhesion molecule 3 were significantly higher, whereas N‐myc downstream regulated gene 2 was lower in the premature prelabor rupture of fetal membranes cervix when compared with the cervix in preterm labor with intact membranes, term labor, and term not labor. PRAM1 and CEACAM3 were localized to immune cells at the cervical stroma and NDRG2 and FGD3 were localized to cervical myofibroblasts. The activity of matrix metalloproteinase‐9 was higher (1.22 ± 4.403‐fold, P < .05) in the cervix in premature prelabor rupture of fetal membranes compared with preterm labor with intact membranes. CONCLUSION: We identified 4 novel proteins with a potential role in the regulation of cervical remodeling leading to premature prelabor rupture of fetal membranes. Our findings contribute to the studies dissecting the mechanisms underlying premature prelabor rupture of fetal membranes and inspire further investigations toward the development of premature prelabor rupture of fetal membranes therapeutics.

Low levels of anti‐secretory factor in placenta are associated with preterm birth and inflammation

Anti‐secretory factor is a protein that regulates secretory and inflammatory processes and preterm birth is associated with inflammation. Therefore, our hypothesis was that anti‐secretory factor might play a role in immune reactivity and homeostasis during pregnancy.

Does Low Molecular Weight Heparin Shorten Term Labor? Editorial Comment

Clinical experience has fostered the belief among some clinicians that women who receive low molecular weight heparins (LMWHs) are less likely to have protracted labor and therefore, less likely to require operative delivery. Previous studies have identified changes in the uterine and cervical extracellular matrix of heparan sulfate proteoglycans in normal and protracted labor. These changes and clinical observations suggest that LMWHs may influence the parturition process and shorten delivery time. This retrospective study investigated the effects of LMWHs on parturition time in pregnant women with a history of thrombotic disorders. The study subjects were 99 nulliparous pregnant women who had been treated with an LMWH (dalteparin) because of a history of previous venous thromboembolism, thrombophilia, or an acute venous thromboembolism during the current pregnancy. The women had been treated for 1 to 6 months before delivery. The control group was comprised of 198 untreated healthy nulliparous women with spontaneous onset of labor matched according to age and parity. The study and control groups were compared with respect to labor time, proportion of operative deliveries, and neonatal outcomes. Among women who had a spontaneous vaginal delivery, labor time was significantly shorter in those treated with dalteparin than in the untreated controls (6 vs. 9 hours, P < 0.0001). The number of operative deliveries was the same in the dalteparin and control groups, but the dalteparin-treated women required fewer operative interventions due to protracted labor (P = 0.0014). There was no difference in neonatal outcome between the groups. These findings suggest that LMWH therapy is associated with shorter labor time and a decreased number of operative interventions for protracted labor.