Search

Background: Spontaneous preterm birth is the leading cause of perinatal morbidity and mortality. Tocolytics are drugs used to inhibit uterine contractions in cases of imminent preterm birth, however, few are effective in stopping labour once initiated and all have side effects. Combination approaches involving drugs that target multiple signalling pathways that regulate contractions may increase efficacy, reduce dosage and improve tolerability. Both non-steroidal anti-inflammatory drugs (NSAIDs) and hydrogen sulphide (H 2 S)-releasing compounds can reduce myometrial contractions. In a novel approach we evaluated the tocolytic properties of ATB-346-a H 2 S-releasing derivative of the NSAID naproxen, shown clinically to reduce pain and inflammation in arthritis., Methods: Using organ baths, paired strips of human myometrium were exposed to increasing concentrations of ATB-346, or equimolar concentrations (10µM and 30µM) of the parent drug, naproxen, or the H 2 S-releasing moiety, 4-hydroxy-thiobenzamide (TBZ), alone. The ability of ATB-346 versus the individual components of ATB-346 to decrease ex vivo spontaneous contractions was investigated, and the potency was compared to a known H 2 S donor, Na 2 S., Results: Acute application of Na 2 S produced a concentration-dependent decrease in force amplitude and force integral (area under the curve) of contraction. ATB-346 produced a more profound decrease in contraction compared to equimolar concentrations of naproxen or TZB alone and was more potent than the equivalent concentration of Na 2 S., Conclusions: ATB-346 exhibits potent tocolytic properties in human myometrium. These exciting results call for further exploration of ATB-346, with a view to repurposing this or similar drugs as novel therapies for delaying preterm labour., Competing Interests: Declarations. Conflict of interest: The authors have nothing to disclose., (© 2024. The Author(s).)

Objective: To compare the effects of nifedipine and indomethacin, used for tocolytic purposes in the treatment of preterm labor (PTL), on fetal-maternal Doppler blood flows and perinatal outcomes., Materials and Methods: Eighty pregnant women between weeks 24 and 32 of gestation who used nifedipine (n = 40) and indomethacin (n = 40) as tocolytic treatments due to PTL were prospectively and consecutively included in the study. Sociodemographic, obstetric, and laboratory and Doppler flow parameters were compared between the groups., Results: Statistically significant differences were observed between the groups in terms of gestational age at delivery and birth weight, Doppler flows (umbilical artery (UA) Pulsatility Index (PI), and UA Resistance Index (RI)) at 12, 24, and 48 h, middle cerebral artery RI at 12 h, and ductus venosus (DV) PI and DV-RI at 12, 24, and 48 h (p < 0.05)., Conclusions: The findings of this study showed that nifedipine and indomethacin used in the treatment of PTL had significant effects on UA-PI and UA-RI Doppler flows at 12, 24, and 24 h, MCA-RI Doppler flows at 12 h, and DV-PI and DV-RI Doppler flows at 12, 24, and 48 h. Further studies involving larger numbers of participants are now needed to support these results., (© 2024 Wiley Periodicals LLC.)

There is a lack of FDA-approved tocolytics for the management of preterm labor (PL). In prior drug discovery efforts, we identified mundulone and mundulone acetate (MA) as inhibitors of in vitro intracellular Ca 2+ -regulated myometrial contractility. In this study, we probed the tocolytic potential of these compounds using human myometrial samples and a mouse model of preterm birth. In a phenotypic assay, mundulone displayed greater efficacy, while MA showed greater potency and uterine-selectivity in the inhibition of intracellular-Ca 2+ mobilization. Cell viability assays revealed that MA was significantly less cytotoxic. Organ bath and vessel myography studies showed that only mundulone exerted inhibition of myometrial contractions and that neither compounds affected vasoreactivity of ductus arteriosus. A high-throughput combination screen identified that mundulone exhibits synergism with two clinical-tocolytics (atosiban and nifedipine), and MA displayed synergistic efficacy with nifedipine. Of these combinations, mundulone+atosiban demonstrated a significant improvement in the in vitro therapeutic index compared to mundulone alone. The ex vivo and in vivo synergism of mundulone+atosiban was substantiated, yielding greater tocolytic efficacy and potency on myometrial tissue and reduced preterm birth rates in a mouse model of PL compared to each single agent. Treatment with mundulone after mifepristone administration dose-dependently delayed the timing of delivery. Importantly, mundulone+atosiban permitted long-term management of PL, allowing 71% dams to deliver viable pups at term (>day 19, 4-5 days post-mifepristone exposure) without visible maternal and fetal consequences. Collectively, these studies provide a strong foundation for the development of mundulone as a single or combination tocolytic for management of PL., Competing Interests: Declaration of Competing Interest None., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Preterm labor leading to preterm birth is the leading cause of infant morbidity and mortality. At the present time, nothing can reliably halt labor once it begins. The knowledge that agonists of the β2 adrenergic receptor relax airway smooth muscle and are effective in the treatment of asthma led to the notion that β2 mimetics would prevent preterm birth by relaxing uterine smooth muscle. The activation of cAMP-dependent protein kinase by β2 receptors is unable to provide meaningful tocolysis. The failure of β2 agonists such as ritodrine and terbutaline to prevent preterm birth suggests that the regulation of uterine smooth muscle is disparate from that of airway. Other smooth muscle quiescent-mediating molecules, such as nitric oxide, relax vascular smooth muscle in a cGMP-protein kinase G-dependent manner; however, nitric oxide activation of protein kinase G fails to explain the relaxation of the myometrium to nitric oxide. Moreover, nitric oxide-mediated relaxation is blunted in preterm labor, and thus, for this reason and because of the fall in maternal blood pressure, nitric oxide cannot be employed as a tocolytic. The β3 adrenergic receptor-mediated relaxation of the human myometrium is claimed to be cAMP-dependent protein kinase-dependent. This is scientifically displeasing given the failure of β2 agonists as tocolytics and suggests a non-canonical signaling role for β3AR in myometrium. The addition of the β3 agonist mirabegron to pregnant human myometrial strips in the tissue bath relaxes oxytocin-induced contractions. Mirabegron stimulates nitric oxide production in myometrial microvascular endothelial cells, and the relaxation of uterine tissue in vitro is partially blocked by the addition of the endothelial nitric oxide synthase blocker Nω-Nitro-L-arginine. Recent data suggest that both endothelial and smooth muscle cells respond to β3 stimulation and contribute to relaxation through disparate signaling pathways. The repurposing of approved medications such as mirabegron (Mybetriq™) tested in human myometrium as uterine tocolytics can advance the prevention of preterm birth.

Spontaneous preterm birth is the leading cause of perinatal morbidity and mortality. Tocolytics are drugs used in cases of imminent preterm birth to inhibit uterine contractions. Nifedipine is a calcium channel blocking agent used to delay threatened spontaneous preterm birth, however, has limited efficacy and lacks preclinical data regarding mechanisms of action. It is unknown if nifedipine affects the pro-inflammatory environment associated with preterm labour pathophysiology and we hypothesise nifedipine only targets myometrial contraction rather than also mitigating inflammation. We assessed anti-inflammatory and anti-contractile effects of nifedipine on human myometrium using in vitro and ex vivo techniques, and a mouse model of preterm birth. We show that nifedipine treatment inhibited contractions in myometrial in vitro contraction assays (P = 0.004 vs. vehicle control) and potently blocked spontaneous and oxytocin-induced contractions in ex vivo myometrial tissue in muscle myography studies (P = 0.01 vs. baseline). Nifedipine treatment did not reduce gene expression or protein secretion of pro-inflammatory cytokines in either cultured myometrial cells or ex vivo tissues. Although nifedipine could delay preterm birth in some mice, this was not consistent in all dams and was overall not statistically significant. Our data suggests nifedipine does not modulate preterm birth via inflammatory pathways in the myometrium, and this may account for its limited clinical efficacy., (© 2023. The Author(s).)

Introduction: Preterm delivery and its complications are among the biggest challenges and health risks in obstetrical practice. Several tocolytic agents are used in clinical practice, although the efficacy and side effect profiles of these drugs are not satisfying. The aim of this study was to investigate the uterus relaxant effect of the coadministration of β 2 -mimetic terbutaline and magnesium sulfate (MgSO 4 ) in an isolated organ bath and to perform in vivo smooth muscle electromyographic (SMEMG) studies in pregnant rats. In addition, we also investigated whether the tachycardia-inducing effect of terbutaline can be reduced by the presence of magnesium, due to the opposite heart rate modifying effects of the two agents., Material and Methods: In the isolated organ bath studies, rhythmic contractions of 22-day- pregnant Sprague-Dawley rats were stimulated with KCl, and cumulative dose-response curves were constructed in the presence of MgSO 4 or terbutaline. The uterus-relaxing effects of terbutaline were also investigated in the presence of MgSO 4 in both normal buffer and Ca 2+ -poor buffer. The in vivo SMEMG studies were carried out under anesthesia with the subcutaneous implantation of an electrode pair. The animals were treated with MgSO 4 or terbutaline alone or in combination in a cumulative bolus injection. The implanted electrode pair also detected the heart rate., Results: Both MgSO 4 and terbutaline reduced uterine contractions in vitro and in vivo, furthermore, the administration of a small dose of MgSO 4 significantly enhanced the relaxant effect of terbutaline, especially in the lower range. However, in Ca 2+ -poor environment, MgSO 4 was not able to increase the effect of terbutaline, indicating the role of MgSO 4 as a Ca 2+ channel blocker. In the cardiovascular studies, MgSO 4 significantly decreased the tachycardia-inducing effect of terbutaline in late pregnant rats., Conclusions: The combined application of MgSO 4 and terbutaline may have clinical significance in tocolysis, which must be confirmed in clinical trials. Furthermore, MgSO 4 could substantially reduce the tachycardia-inducing side effect of terbutaline., (© 2023 The Authors. Acta Obstetricia et Gynecologica Scandinavica published by John Wiley & Sons Ltd on behalf of Nordic Federation of Societies of Obstetrics and Gynecology (NFOG).)

In pursuit of more effective-labor delaying tocolytic agents, the prostaglandin F2α (PGF2α) receptor (FP) modulator PDC113.824 [(6S)-2] represents a potent lead for developing therapy to treat preterm birth. Derivatives of FP modulator (6S)-2 were synthesized, possessing respectively 5- and 7-hydroxyl groups on the indolizidin-2-one amino acid (I 2 aa) residue. The effects of the alcohol substituents were examined in a PGF2α-induced myometrial contraction assay. Based on knowledge of dihedral angle values of model I 2 aa peptides from X-ray analyses, the results of the study indicate respectively encouraging and limited potential for creating improved tocolytic agents by modifications at the 5- and 7-positions., (© 2022 European Peptide Society and John Wiley & Sons Ltd.)

The intracellular signaling pathways that regulate myometrial contractions can be targeted by drugs for tocolysis. The agents, 2-APB, glycyl-H-1152, and HC-067047, have been identified as inhibitors of uterine contractility and may have tocolytic potential. However, the contraction-blocking potency of these novel tocolytics was yet to be comprehensively assessed and compared to agents that have seen greater scrutiny, such as the phosphodiesterase inhibitors, aminophylline and rolipram, or the clinically used tocolytics, nifedipine and indomethacin. We determined the IC 50 concentrations (inhibit 50% of baseline contractility) for 2-APB, glycyl-H-1152, HC-067047, aminophylline, rolipram, nifedipine, and indomethacin against spontaneous ex vivo contractions in pregnant human myometrium, and then compared their tocolytic potency. Myometrial strips obtained from term, not-in-labor women, were treated with cumulative concentrations of the contraction-blocking agents. Comprehensive dose-response curves were generated. The IC 50 concentrations were 53 µM for 2-APB, 18.2 µM for glycyl-H-1152, 48 µM for HC-067047, 318.5 µM for aminophylline, 4.3 µM for rolipram, 10 nM for nifedipine, and 59.5 µM for indomethacin. A single treatment with each drug at the determined IC 50 concentration was confirmed to reduce contraction performance (AUC) by approximately 50%. Of the three novel tocolytics examined, glycyl-H-1152 was the most potent inhibitor. However, of all the drugs examined, the overall order of contraction-blocking potency in decreasing order was nifedipine > rolipram > glycyl-H-1152 > HC-067047 > 2-APB > indomethacin > aminophylline. These data provide greater insight into the contraction-blocking properties of some novel tocolytics, with glycyl-H-1152, in particular, emerging as a potential novel tocolytic for preventing preterm birth., (© 2022. The Author(s).)

Preterm labor leading to preterm birth is the leading cause of infant morbidity and mortality. Although β2 adrenergic agonists fail to provide adequate tocolysis, the expression of the β3 adrenergic receptor in myometrium and its unique signaling suggest a role for β3 agonist in the management of preterm labor. Western blot analysis showed that the β3 adrenergic receptor expression increased in human pregnancy myometrium compared to nonpregnant tissues (p < 0.0001). There was no difference in β3 adrenergic receptor expression throughout pregnancy (p > 0.05). The addition of the β3 agonist mirabegron in the tissue bath relaxed oxytocin contracted myometrium with an EC 50 of 41.5 µM. Relaxation was partially blocked by the addition of the eNOS blocker Nω-nitro-L-arginine, or the large conductance potassium channel blocker paxilline. Combination of Nω-nitro-L-arginine and paxilline prevented mirabegron-mediated relaxation. Imaging revealed that the β3 adrenergic receptors are expressed by both myocyte and microvascular endothelial cells isolated from human myometrium. Nitric oxide production measured by 4-amino-5-methylamino-2',7'-difluorofluorescein diacetate revealed that mirabegron stimulated nitric oxide production in myometrial endothelial cells. These data suggest that both endothelial and smooth muscle cells contribute to relaxation through disparate signaling pathways. Repurposing of approved medications tested in human myometrium as uterine tocolytics can advance prevention of preterm birth. These data argue that further examination of β3 adrenergic receptor signaling in myometrium may reveal mirabegron as a useful tocolytic in combination tocolysis regimens., (© 2022. The Author(s).)

In this study, the effects of isoxsuprine hydrochloride applied 14 and 15 days after insemination in Anatolian Merino Sheep on lamb yield and some blood parameters were investigated. The research was conducted during the breeding season and 54 ewes inseminated on the same day were used. The ewes were assigned to three groups. Group I: For the placebo effect, physiological saline was injected on the 14th day into half of the control group and on the 15th day into the other half after insemination (n=18). Group II: Tocolytic drug was injected on the 14th day after insemination (n=18). Grop III: Tocolytic drug was injected on the 15th day after insemination (n=18). As the tocolytic drug, isoxsuprine hydrochloride (HCl) 3 ml (Utelax, Sanovel, Türki̇ye) was used intramuscularly. The number of pregnant and viviparous ewes, single and multiple birth ewes, lambs per viviparous ewes were determined as reproductive parameters. Blood progesterone, cortisol and calcium concentration were determined. As a result, it was determined that the single application of isoxsuprine hydrochloride (3 ml) in the implantation period did not have a positive or negative effect on reproductive parameters, and did not change the blood progesterone, calcium and cortisol concentration in ewes., (Copyright© by the Polish Academy of Sciences.)

Ethnopharmacological Relevance: The species Lippia origanoides Kunth, popularly known as "salva-de-marajó", is used in Brazilian traditional "quilombola" communities to treat menstrual cramps and uterine inflammation., Aim of the Study: Evaluate the spasmolytic activity of Lippia origanoides essential oil (LOO) on experimental models of uterine conditions related to menstrual cramps and investigate its mechanism of action., Materials and Methods: Virgin rat-isolated uterus was mounted in the organ bath apparatus to evaluate the spasmolytic effect of LOO on basal tonus and contractions induced by carbachol, KCl, or oxytocin. We used pharmacological agents to verify the relaxation mechanism of LOO. The evaluation of uterine contractility in virgin rats, after treatment with LOO for three consecutive days, was carried out by the construction of a concentration-response curve with oxytocin or carbachol. The primary dysmenorrhea animal model was replicated with an injection of estradiol cypionate in female mice for three consecutive days, followed by intraperitoneal application of oxytocin., Results: LOO relaxed the rat uterus precontracted with 10 -2 IU/mL oxytocin (logEC 50  = 1.98 ± 0.07), 1 μM carbachol (logEC 50  = 1.42 ± 0.07) or 60 mM KCl (logEC 50  = 1.53 ± 0.05). It was also able relax uterus on spontaneous contractions (logEC 50  = 0.41 ± 0.05). Preincubation with glibenclamide, propranolol, phentolamine or L-NAME in contractions induced by carbachol did not alter significantly the relaxing effect of LOO. However, in the presence of 4-aminopyridine, CsCl or tetraethylammonium there was a reduction of LOO potency, whereas the blockers methylene blue, ODQ, aminophylline and heparin potentiated the LOO relaxing effect. Preincubation with LOO in a Ca 2+ free medium at concentrations of 27 μg/mL or 81 μg/mL reduced the contraction induced by carbachol. The administration of LOO for 3 days did not alter uterus contractility. The treatment with LOO at 30 or 100 mg/kg intraperitoneally, or 100 mg/kg orally, inhibited writhing in female mice. The association of LOO at 10 mg/kg with nifedipine or mefenamic acid potentiated writhing inhibition in mice., Conclusions: The essential oil of L. origanoides has tocolytic activity in rat isolated uterus pre-contracted with KCl, oxytocin, or carbachol. This effect is possibly related to the opening of potassium channels (K ir , K V, and K Ca ), cAMP increase, and diminution of intracellular Ca 2+ . This relaxant effect, probably, contributed to reduce the number of writhings in an animal model of dysmenorrhea being potentiated by nifedipine or mefenamic acid. Taken together, the results here presented indicate that this species has a pharmacological potential for the treatment of primary dysmenorrhea, supporting its use in folk medicine., (Copyright © 2022 Elsevier B.V. All rights reserved.)

A great need exists to develop tocolytic and uterotonic drugs that combat poor, labor-related maternal and fetal outcomes. A widely utilized method to assess novel compounds for their tocolytic and uterotonic efficacy is the isometric organ bath contractility assay. Unfortunately, water-insoluble compounds can be difficult to test using the physiological, buffer-based, organ bath assay. Common methods for overcoming solubility issues include solvent variation, cosolvency, surfactant or complexion use, and emulsification. However, these options for drug delivery or formulation can impact tissue function. Therefore, the goal of this study was to evaluate the ability of common solvents, surfactants, cosolvents, and emulsions to adequately solubilize compounds in the organ bath assay without affecting mouse myometrial contractility. We found that acetone, acetonitrile, and ethanol had the least effect, while dimethylacetamide, ethyl acetate, and isopropanol displayed the greatest inhibition of myometrial contractility based on area under the contractile curve analyses. The minimum concentration of surfactants, cosolvents, and human serum albumin required to solubilize nifedipine, a current tocolytic drug, resulted in extensive bubbling in the organ bath assay, precluding their use. Finally, we report that an oil-in-water base emulsion containing no drug has no statistical effect beyond the control (water), while the drug emulsion yielded the same potency and efficacy as the freely solubilized drug., (© 2021. The Author(s).)

Currently available tocolytics are ineffective at significantly delaying preterm birth. This is due in part to our failure to better understand the mechanisms that drive spontaneous preterm labor (sPTL). Cyclic nucleotides are not the primary contributors to myometrial quiescence, but instead nitric oxide (NO)-mediated protein S -nitrosation (SNO) is integral to the relaxation of the tissue. Connexin-43 (Cx43), a myometrial "contractile-associated protein" that functions as either a gap junction channel or an hemichannel (HC), was the focus of this study. Protein analysis determined that Cx43 is downregulated in sPTL myometrium. Furthermore, Cx43 is S -nitrosated by NO, which correlates with an increase of phosphorylated Cx43 at serine 368 (Cx43-pS368 -gap junction inhibition) as well as an increase in the HC open-state probability (quiescence). Pharmacologic inhibition of Cx43 with 18 β -glycyrrhetinic acid (18 β -GA) exhibits a negative inotropic effect on the myometrium in a dose-dependent manner, as does administration of nebivolol, an NO synthase activator that increases total protein SNOs. When 18 β -GA and nebivolol were coadministered at their IC 50 values, the effect on contractile dynamics was additive and all but eliminated contractions. The development of new tocolytics demands a better understanding of the underlying mechanisms of sPTL. Here it has been shown that 18 β -GA and nebivolol leverage dysregulated pathways in the myometrium, resulting in a novel approach for the treatment of sPTL. SIGNIFICANCE STATEMENT: Although there are many known causes of preterm labor (PTL), the mechanisms of "spontaneous" PTL (sPTL) remain obfuscated, which is why treating this condition is so challenging. Here we have identified that connexin-43 (Cx43), an important contractile-associated protein, is dysregulated in sPTL myometrium and that the pharmacologic inhibition of Cx43 and its S -nitrosation with 18 β -glycyrrhetinic acid and nebivolol, respectively, significantly blunts contraction in human myometrial tissue, presenting a novel approach to tocolysis that leverages maladjusted pathways in women who experience sPTL., (Copyright © 2021 by The Author(s).)

The essential oil of Lippia microphylla (LM-OE) presents several pharmacological activities. This work evaluates the tocolytic effect of LM-OE on rats. LM-OE inhibited phasic contractions and relaxed tonic contractions on rat uterus. Considering that nitric oxide (NO) pathway regulates uterine contraction, LM-OE potency was attenuated in the presence of NO synthase (NOS) inhibitor and this reduction was reversed in the presence of a NOS substrate. Similarly, the relaxant potency of LM-OE was reduced in the presence of soluble guanylyl cyclase (sGC) and protein kinase G (PKG) inhibitors. LM-OE also demonstrates a positive modulation of large and small conductance calcium-activated, voltage-gated and adenosine triphosphate-sensitive potassium channels and inhibited curves to CaCl 2 as well as relaxed the uterus pre-contracted by S-(-)-Bay K8644, suggesting voltage-gated calcium channels type-1 (Ca V 1) blockade. Thus, the tocolytic effect of LM-OE on rat involves positive modulation of NO/NOS/sGC/PKG/K + -channels pathway and Ca 2+ influx blockade through Ca V 1.[Formula: see text].

Background: Currently available tocolytic agents are not effective treatment for preterm labor beyond 48 h. A major reason is the development of maternal side effects which preclude the maintenance of an effective steady-state drug concentration. One strategy that can mitigate these side effects is utilizing synergistic drug combinations to reduce the drug concentrations necessary to elicit a clinical effect. We have previously shown that three anoctamin 1 (ANO1) antagonists mediate potent relaxation of precontracted human uterine smooth muscle (USM). In this study, we aimed to determine whether a combination of sub-relaxatory doses of tocolytic drugs in current clinical use [the L-type voltage-gated calcium channel (VGCC) blocker, nifedipine (NIF); and the β 2 -adrenergic (β2AR) agonist, terbutaline (TRB)] will potentiate USM relaxation with two ANO1 antagonists [benzbromarone (BB) and MONNA (MN)]., Objective: This study sought to examine the synergistic potency and mechanistic basis of two ANO1 antagonists with currently available tocolytic drugs. Functional endpoints assessed included relaxation of pre-contracting pregnant human USM tissue, inhibition of intracellular calcium release, and reduction of spontaneous transient inward current (STIC) recordings in human uterine smooth muscle cells., Methods: Human myometrial strips and primary human USM cells were used in organ bath and calcium flux experiments with different combinations of sub-threshold doses of ANO1 antagonists and terbutaline or nifedipine to determine if ANO1 antagonists potentiate tocolytic drugs., Results: The combination of sub-threshold doses of two ANO1 antagonists and current tocolytic drugs demonstrate a significant degree of synergy to relax human pregnant USM compared to the effects achieved when these drugs are administered individually., Conclusion: A combination of sub-threshold doses of VGCC blocker and β2AR agonist with ANO1 antagonists potentiates relaxation of oxytocin-induced contractility and calcium flux in human USM ex vivo. Our findings may serve as a foundation for novel tocolytic drug combinations.

Despite the wide application of carvacrol (CAR) in different biological and medical areas, there is still insufficient electrophysiological data on the mechanisms of action of CAR, particularly in the pregnant uterine function. The aim of this study was to evaluate the in vitro tocolytic effect of CAR on the contractility of isolated pregnant rat uterus in the presence of a calcium channel antagonist (nifedipine) and a cyclooxygenase inhibitor (indomethacin). The uteri were isolated from pregnant Wistar rats at 16-18 days of pregnancy and suspended in an isolated organ bath chamber containing a Ringer's physiological solution and aerated with 95% O 2 and 5% CO 2 . Samples were used in functional tests to evaluate the inhibitory effect of CAR at increasing concentrations on the rhythmic spontaneous, oxytocin-induced phasic, K + -induced tonic, and Ca 2+ -induced contractions. The differences in inhibitory concentration-50 and E max among the compounds were determined using the one-way ANOVA followed by a post hoc Student-Newman-Keuls or Bonferroni test, in all casesP < 0.05 was considered statistically significant. Nifedipine was used as positive controls where required. CAR caused a significant concentration-dependent inhibition of the uterine contractions induced by the pharmaco- and electro-mechanic stimuli. We showed that the inhibitory effects of CAR depends on the type of muscle contraction stimuli, and that it acts stronger in spontaneous rhythmic activity and in contractions of isolated rat uterus induced by Ca 2+ . Nifedipine was more potent than CAR and indomethacin on the uterine contractility (P < 0.05), but none of them was more effective than nifedipine. Therefore, the tocolytic effect induced by CAR was associated with the blockade of the calcium channels in the pregnant rat uterus. This property placed CAR as a potentially safe and effective adjuvant agent in cases of preterm labor, an area of pharmacological treatment that requires urgent improvement., Competing Interests: None

We tested the hypothesis that 17α-hydroxyprogesterone caproate (17α-OHP-C) may decrease preterm delivery (PTD) in women with placenta praevia. This was a randomised controlled trial included 114 women with placenta praevia (between 24 and 28 weeks). They were randomly assigned to group I (17α-OHP-C) who received weekly injection of 17α-OHP-C (250 mg/IM) till completing 37 weeks' gestation or group II (Non 17α-OHP-C). The percentage of placenta praevia patients went into PTD in the 17α-OHP-C group was significantly less in comparison to the PTD in the Non 17α-OHP-C group (∼37% vs. 63.5%, p  = .004). Furthermore, the mean gestational age was significantly longer (36.7 ± 0.7 vs. 34.9 ± 1.2 weeks, p  < .000), the mean number of bleeding attacks was significantly less and the mean birth weight was significantly higher (2841 ± 159 vs. 2561 ± 168 g, p  < .000). In conclusion, maintenance tocolysis with intramuscular 17α-OHP-C in placenta praevia women appears beneficial in decreasing the number of bleeding attacks, the percentage of PTD and the neonatal ICU admission.IMPACT STATEMENT What is already known on this subject? Over the last two decades, a large number of studies indicated that placenta praevia is a major risk factor for preterm labour and prematurity with its neonatal complications. Increasing caesarean section rates had proportionally increased the incidence of placenta praevia. What do the results of this study add? Up to now, the effective and safe tocolytic agent among these patients is not established. The results of this study (prospective, randomised and controlled with calculated sample size) added a considerable support for hydroxyprogesterone caproate as an effective, safe and cheap tocolytic agent with excellent patient compliance. What are the implications of these findings for clinical practice and/or further research? Our findings may prompt researchers to conduct a large multicentre study to evaluate the prophylactic use of hydroxyprogesterone caproate to decrease preterm labour due to placenta praevia.

Ethnopharmacology Relevance: Pimpinella anisum is a well-known traditional medicinal herb which has been used in folk medicine as an antiulcer, anticancer, antibacterial and as a muscle relaxant., Aim of the Study: This study was performed to explore the modulatory effects of Pimpinella anisum on term-pregnant rat uterine contractility and to investigate its possible underlying mechanisms., Material and Methods: Intact uterine strips without endometrial layer were isolated from female term-pregnant Wistar rats (22 days of gestation) and mounted in a tissue bath apparatus for in vitro isometric force recording. The effects of different concentrations of Pimpinella anisum extract (PAE) (1, 3, 5, and 7 mg/mL) were examined on uterine contractions generated spontaneously or induced with oxytocin (5 nmol/L), Bay K8644 (1 μmol/L), and carbachol (10 μmol/L). In some experiments, PAE was applied on depolarized myometrium in the presence of high-KCl solution (60 mmol/L). The effect on Ca 2+ release was also examined., Results: Application of PAE significantly reduced uterine contractions generated spontaneously or induced with oxytocin, Bay K8644, and carbachol in a concentration-dependent manner (n = 7; P < 0.01). In depolarized myometrium, PAE significantly reduced the tonic force induced by high-KCl solution (n = 7; P < 0.01). PAE prevented oxytocin-induced transient contraction in the entire absence of external calcium (n = 7; P < 0.01)., Conclusion: The present findings demonstrate the potentials of PAE to relax pregnant uterine contractions possibly by blocking Ca 2+ entry via L-type calcium channels and inhibiting Ca 2+ release from the internal store. The tocolytic effects of PAE may be a potential adjuvant against strong premature uterine contractions which threaten early pregnancy although clinical studies are required., Competing Interests: Declaration of competing interest None declared., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Ethno-Pharmacological Relevance: Corchorus olitorius is reportedly used in ethno-medicine to arrest threatened miscarriage and other conditions associated with excessive uterine contractions. The plant is also used as a purgative, demulscent and an anti-inflammatory agent., Aim of the Study: Against the background of ethno-medicinal use, this current work was designed to evaluate the gastrointestinal and uterine smooth muscles relaxant and anti-inflammatory effects of Corchorus olitorius leaf extract (COLE)., Materials and Methods: Pieces of uterine and gastrointestinal tissues were suspended separately in organ baths containing ideal physiological salt solutions bubbled with air and were tested for responses to standard drugs and COLE, then repeated in the presence of antagonists. Anti-inflammatory study was carried out via the egg albumin-induced paw edema model in rats., Results: The application of COLE to pieces of uterine tissue significantly decreased the amplitudes of contractions in a dose dependent manner such that the highest dose applied (666.67 μg/ml) achieved a 100% inhibitory effect. Oxytocin induced contractions were also significantly inhibited by both salbutamol and COLE. On the isolated rabbit jejunum, the effect of COLE was also inhibitory and like atropine, significantly inhibited acetylcholine induced contractions. In the in vivo study, the extract inhibited charcoal meal movement in test rats when compared with control. Anti-inflammatory effect of COLE was significant and compared favourably with that of aspirin following in vivo trials., Conclusions: COLE therefore, may be a good tocolytic, anti-diarrheal and anti-inflammatory agent and offers hope of new drug discovery for such uses., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Background: The herbal medicine Bryophyllum pinnatum has been used as a tocolytic agent in anthroposophic medicine and, recently, in conventional settings alone or as an add-on medication with tocolytic agents such as atosiban or nifedipine. We wanted to compare the inhibitory effect of atosiban and nifedipine on human myometrial contractility in vitro in the absence and in the presence of B. pinnatum press juice (BPJ)., Methods: Myometrium biopsies were collected during elective Caesarean sections. Myometrial strips were placed under tension into an organ bath and allowed to contract spontaneously. Test substances alone and at concentrations known to moderately affect contractility in this setup, or in combination, were added to the organ bath, and contractility was recorded throughout the experiments. Changes in the strength (measured as area under the curve (AUC) and amplitude) and frequency of contractions after the addition of all test substances were determined. Cell viability assays were performed with the human myometrium hTERT-C3 and PHM1-41 cell lines., Results: BPJ (2.5 μg/mL), atosiban (0.27 μg/mL), and nifedipine (3 ng/mL), moderately reduced the strength of spontaneous myometrium contractions. When BPJ was added together with atosiban or nifedipine, inhibition of contraction strength was significantly higher than with the tocolytics alone (p = 0.03 and p < 0.001, respectively). In the case of AUC, BPJ plus atosiban promoted a decrease to 48.8 ± 6.3% of initial, whereas BPJ and atosiban alone lowered it to 70.9 ± 4.7% and to 80.9 ± 4.1% of initial, respectively. Also in the case of AUC, BPJ plus nifedipine promoted a decrease to 39.9 ± 4.6% of initial, at the same time that BPJ and nifedipine alone lowered it to 78.9 ± 3.8% and 71.0 ± 3.4% of initial. Amplitude data supported those AUC data. The inhibitory effects of BPJ plus atosiban and of BPJ plus nifedipine on contractions strength were concentration-dependent. None of the test substances, alone or in combination, decreased myometrial cell viability., Conclusions: BPJ enhances the inhibitory effect of atosiban and nifedipine on the strength of myometrial contractions, without affecting myometrium tissue or cell viability. The combination treatment of BPJ with atosiban or nifedipine has therapeutic potential.

Ethnopharmacological Relevance: The leaves of Justicia flava are traditionally used in the South of Nigeria to prevent preterm births., Aim of the Study: In this study, the activity of the methanol leaf extract of J. flava (JF) was investigated on uterine contractility in non-pregnant and pregnant isolated mouse tissues., Material and Methods: The effects on spontaneous, oxytocin, and KCl-induced contractions were determined. The effects in calcium-free media were also determined. Possible mechanisms of activity were investigated using receptor and channel modulators. Mass spectrometric analysis was additionally performed on the leaf extract to identify secondary metabolites., Results: JF was observed to inhibit spontaneous, oxytocin and high KCl-induced uterine contractility. JF also inhibited contractions in Ca 2+ -free media. JF was found to exert its inhibitory effect via interaction with inositol triphosphate and ryanodine receptors and also through modulation of K + - channels. Lignans and alkaloids were identified with the lignans being the most abundant in JF., Conclusion: JF has been shown to potently inhibit uterine contractions in non-pregnant and pregnant isolated mouse uterus. The inhibitory activity of JF has been shown to occur via blockade of extracellular and intracellular calcium entry and these effects may be due to the lignans identified in - JF. JF has therefore been shown in this study to be a lead plant in the discovery of new drugs with uterine inhibitory activity., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Oxytocin receptor antagonists (OTR-A) have been developed as tocolytics for the management of preterm labour due to the significant role of oxytocin (OT) in the onset of both term and preterm labour. Similar to OT, prostaglandins (PGs) play key roles in myometrial contractility and cervical ripening. Inhibition of PG synthesis/activity is used to delay preterm birth. Thus, targeting the PG pathway in combination with an OTR-A may be an effective strategy for delaying preterm delivery. In this study, we examined the effects of atosiban and nolasiban on PGF 2α -induced contractions and pro-inflammatory responses in human pregnant myometrium. Both OTR-As, atosiban and nolasiban, inhibited PGF 2α -induced contractions in a dose-dependent manner (p < 0.001 and p < 0.01, respectively). These inhibitory effects involved the suppression of PGF 2α -mediated increase in intracellular calcium levels. In addition, the OTR-As significantly suppressed PGF 2α -induced activation of pro-inflammatory pathways such as NF-κB and mitogen activated protein kinases (MAPKs), and the subsequent expression of contraction-associated-protein, COX-2. We have demonstrated that atosiban and nolasiban not only inhibit contractions elicited by OT, but also inhibit contractions and inflammation induced by PGF 2α . This suggests a possible crosstalk between OTR and PG receptor signalling and highlights the importance of understanding G protein-coupled receptor interactions/crosstalk in the development of future tocolytics.

Despite considerable progress in the field of perinatal care, infectious diseases, especially when caused by gram negative bacteria, remain a major reason for neonatal morbidity and mortality. Notably infants born prematurely and those with very low birth weight are at risk due to their immature and deficient immune system and their prolonged hospitalization which promotes nosocomial infections. In case of impending preterm birth, betamethasone is given to induce lung maturation and tocolytic agents like indomethacin or fenoterol are administered to suppress premature labor. The aim of this study was to analyze the effects of these drugs on the immune system of mothers and neonates. Therefore, mononuclear cells from cord blood and peripheral maternal blood were stimulated with Escherichia coli and incubated with betamethasone, indomethacin and fenoterol. Subsequently the effect of the treatment on cytokine production was determined. Betamethasone alone and in combination with tocolytic agents inhibited the production of pro- and anti-inflammatory cytokines. Not only does betamethasone dampen the immune response by reducing the production of cytokines, it also has a variety of other detrimental short- and long-term effects on the neonate. In conclusion we would recommend using biological markers to determine if premature labor actually leads to preterm birth and subsequently administer betamethasone only to mothers giving birth prematurely., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Background and Purpose: Prostanoid EP 2 receptor agonists exhibit several activities including ocular hypotension, tocolysis and anti-inflammatory activity. This report describes the affinity and selectivity of a structurally novel, non-prostanoid EP 2 receptor agonist, PGN-9856, and its therapeutic potential., Experimental Approach: The pharmacology of a series of non-prostanoid EP 2 receptor agonists was determined according to functional and radioligand binding studies, mostly using human recombinant prostanoid receptor transfectants. The selectivity of PGN-9856, as the preferred compound, was subsequently determined by using a diverse variety of non-prostanoid target proteins. The therapeutic potential of PGN-9856 was addressed by determining its activity in relevant primate cell, tissue and disease models., Key Results: PGN-9856 was a selective and high affinity (pKi ≥ 8.3) ligand at human recombinant EP 2 receptors. In addition to high affinity binding, it was a potent and full EP 2 receptor agonist with a high level of selectivity at EP 1 , EP 3 , EP 4 , DP, FP, IP and TP receptors. In cells overexpressing human recombinant EP 2 receptors, PGN-9856 displayed a potency (pEC 50 ≥ 8.5) and a maximal response (increase in cAMP) comparable to that of the endogenous agonist PGE 2 . PGN-9856 exhibited no appreciable affinity (up 10 μM) for a range of 53 other receptors, ion channels and enzymes. Finally, PGN-9856 exhibited tocolytic, anti-inflammatory and long-acting ocular hypotensive properties consistent with its potent EP 2 receptor agonist properties., Conclusions and Implications: PGN-9856 is a potent, selective and efficacious prostanoid EP 2 receptor agonist with diverse potential therapeutic applications: tocolytic, anti-inflammatory and notably anti-glaucoma., (© 2018 The Authors. British Journal of Pharmacology published by John Wiley & Sons Ltd on behalf of British Pharmacological Society.)

Objectives To measure the tocolytic effect of the combination of the oxytocin receptor antagonist atosiban with the β-mimetic agent fenoterol on human myometrium of pregnant women. Methods An in vitro study of contractility in human myometrium at the Laboratory of the Department of Obstetrics, University Hospital of Zürich, Switzerland, was performed. Thirty-six human myometrial biopsies were obtained during elective caesarean sections of singleton pregnancies at term. Tissue samples were exposed to atosiban, fenoterol and the combination of atosiban with fenoterol. Contractility was measured as area under the curve during 30 min of spontaneous contractions. The effect of treatment was expressed as the percentage of change from basal activity during 30 min of exposure. Differences were calculated using a paired Wilcoxon signed-rank test. An additive effect of dual tocolysis was assumed when no significant difference was detected between the observed and expected inhibition of dual tocolysis. When inhibition was greater or lower than expected, the dual combination was characterised as "synergistic" or "antagonistic", respectively. Results Atosiban and fenoterol alone suppressed contractions by a median of 43.2% and 29.8%, respectively. The combination of atosiban plus fenoterol was measured at a level of 67.3% inhibition. There was no significant difference in the expected (63.2%) and observed inhibition effect of dual tocolysis (P=0.945). Conclusion This study demonstrated an additive effect of dual tocolysis of atosiban and fenoterol on human myometrium in vitro, but no synergistic or antagonistic effect.

Objective: Antenatal magnesium sulfate (MgSO 4 ) is known to affect the central nervous system of preterm infants, and there is biologic rationale for influence on other phenotypes. This study investigated the effect of MgSO 4 exposure on the trajectory of ponderal index (PI, kg/m 3 ) from birth to 2 years of age., Study Design: A secondary analysis of a U.S. randomized controlled trial investigating MgSO 4 versus placebo administration among women at high risk for preterm delivery was performed. Multivariable logistic regression was used to assess the relationship between PI from birth to 2 years of age and exposure to MgSO 4 versus placebo., Results: There was a larger decrement in PI from birth to 2 years of age in infants exposed to MgSO 4 compared with placebo ( p  = 0.032). There was a statistically significant one-way interaction between newborn sex and treatment group ( p  = 0.019). Change in PI in males exhibited a greater decrement in those exposed to MgSO 4 versus placebo ( p  = 0.227), whereas female infants exposed to MgSO 4 had a smaller decrement ( p  = 0.04)., Conclusion: MgSO 4 exposure in preterm infants is associated with a larger decrease in PI from birth to 2 years of age. In addition, the direction of effect of MgSO 4 on the change in PI over the first 2 years of life is different by sex., Competing Interests: None., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

The aim of this study was to investigate the tocolytic properties of Ananas comosus extract in rat and human uterine tissue in vitro and in the rat in vivo. Organ bath technique was employed to perform functional studies in vitro. The PhysioTel transmitter was implanted in SD rats to measure the changes in intrauterine pressure (IUP) in vivo. Analyses of F2 was performed using LC-HRMS. F2 produced a non-selective inhibitory response on oxytocin, prostaglandin F2α, acetylcholine and KCl. The inhibitory activity of F2 on oxytocin-induced contraction was not attenuated by propranolol, TEA, glibenclamide and indomethacin. Nω-Nitro-L-arginine, a nitric oxide synthase inhibitor, suppressed the maximal tocolytic activity of F2 by 25%. DIDS, an inhibitor of chloride channels, appeared to suppress the relaxant effect of F2. F2 suppressed the oxytocin-induced contraction in Ca 2+ free solution. The in vivo tocolytic activity of F2 and ritodrine were observed in non-pregnant rats during the estrous stage by suppressing the frequency and amplitude of IUP peaks following intrauterine administration. Chemical analysis confirmed the involvement of citric acid in the tocolytic activity of F2. However, another less polar fraction is essential to accompany citric acid to produce such potent inhibitory response of F2. It is likely that F2 exerted tocolytic activity by multiple mechanisms, including antagonizing L-type Ca 2+ channels, interfering with the intracellular Ca 2+ release mechanism and releasing nitric oxide. F2 would be a promising candidate to develop as a tocolytic agent., (Copyright © 2018 Elsevier Masson SAS. All rights reserved.)

Purpose: Cerebral palsy is often associated with prematurity and magnesium sulfate (MgSO 4 ) has been used as a neuroprotector, with favorable results. However, its mechanism of action has not been fully elucidated. This study aimed to evaluate the association between MgSO 4 at the imminent premature delivery and neonatal hemodynamic effects., Materials and Methods: A cross-sectional study involving 94 newborns (NB) between 24 and 32 weeks at a Brazilian hospital was performed. Bivariate analysis between the use or the non-use of MgSO 4 and hemodynamic characteristics was performed, using the Chi-square test., Results: NB were evaluated between those who received MgSO 4 (27.7) and those who did not (72.3%). Normal heart rate was verified in 62.8% of NB, normal respiratory rate in 70.2%, and normal temperature in 22.3%. Oxygen saturation higher or equal than 95% was evidenced in 85.1% of NB, normal hemoglucotest in 74.5%, and hemoglobin greater or equal than 16.4 g/dL in 30.9%. Non-invasive ventilation was performed in 48.9% of NB, while 51.1% were submitted to endotracheal ventilation. There was no significance relation detected between the use of MgSO 4 and the hemodynamic characteristics., Conclusions: MgSO 4 does not appear to influence hemodynamic factors as a cause of the neuroprotection in premature NB.

Objective: We aimed to assess the impact of antenatal MgSO 4 therapy given to women with PPROM before 32 weeks' gestation on latency, maternal outcomes, perinatal outcomes, and neurodevelopmental outcomes., Methods: We undertook a retrospective cohort observational study of 184 singleton pregnancies complicated by PPROM at 23°-31 6  weeks who were hospitalized and received magnesium therapy for tocolysis (MgSO 4 group) or did not receive tocolytic therapy (no MgSO 4 group) between 2005 and 2013. Furthermore, patients were subdivided into two groups based on the gestational age at the onset of PPROM (23°-27 6 weeks' gestation and 28°-31 6 weeks' gestation)., Results: We included 184 women, of whom 143 received magnesium therapy and 41 did not. The latency period was significantly longer in the MgSO 4 group compared with no MgSO 4 group (7.9 ± 9.0 versus 4.0 ± 6.0 days, p = .0017). Antenatal magnesium therapy was significantly associated with decreased stillbirth (1.4% versus 14.6%, p = .0012) and perinatal mortality (7% versus 19.5%, p = .0375) without significant increase in the risk of neonatal morbidities and chorioamnionitis. However, neonates who were exposed to antenatal MgSO 4 were associated with higher Mg levels (3.63 ± 1.05 mg/dl versus 2.13 ± 0.48 mg/dl, p < .0001) and phosphate levels (6.90 ± 1.36 mg/d versus 6.40 ± 1.01 mg/dl, p = .0459) than those who were not exposed. Neonates who were exposed to MgSO 4 showed significantly reduced risks of IVH (20.4% versus 58.3%; RR, 0.35; 95%CI, 0.17-0.71) and PVL (27.8% versus 58.3%; RR, 0.48; 95%CI, 0.25-0.91) in the subgroup of 23°-27 6 weeks' gestation. And the incidence of developmental delay in the subgroup of 23°-27 6 weeks' gestation was significantly lower in the MgSO 4 group (6.5% versus 36.4%; RR, 0.18; 95%CI, 0.05-0.69). However, there were no significant differences in the development of IVH, PVL, and developmental delay between the two groups for patients in the subgroup of 28°-31 6 weeks' gestation. A similar trend was observed for cerebral palsy, with 22.2% of unexposed children affected compared with only 7.0% of exposed children (RR, 0.31; 95%CI, 0.10-1.00)., Conclusions: Antenatal magnesium therapy in women with PPROM before 32 weeks' gestation could prolong latency period, allowing for corticosteroid benefit. Moreover, MgSO 4 showed fetal neuroprotective effects for neonatal IVH and PVL, and for developmental delay in infancy while prolonging latency. However, these benefits were primarily limited to the subgroup of 23°-27 6 weeks' gestation and prolonged in utero exposure to MgSO 4 was associated with bone mineralization in the neonates.

Purpose: Uterine activity plays a crucial role in labor, especially when utero-tonic materials are administered. We aimed to determine the electrical responsiveness of the uterine musculature to labor augmentation with oxytocin using electrical uterine myography (EUM) technology, and to assess whether the kinetics of the EUM device may serve as a predictor for successful vaginal delivery., Methods: EUM prospectively measured electrical uterine activity in women with singleton gestations at term (≥ 37 + 0 weeks) undergoing labor augmentation by oxytocin administration. The results were reported as the EUM index, which represented the mean electrical activity in 10-min intervals and measured in units of microwatt per second (mW/s). Measurements were performed at least 30 min before oxytocin initiation and until at least four contractions per 10 min were recorded by standard tocodynamometry. The delta EUM index was defined as the difference between the mean EUM index before and after the initiation of oxytocin., Results: The mean EUM index increased significantly during oxytocin augmentation in all the parturients (P < 0.001). Mean and minimum (but not maximum) uterine electrical activity during oxytocin infusion correlated with the baseline uterine activity. The delta EUM index was not significantly affected by demographic or obstetric parameters. There was no correlation between the delta EUM index and time to delivery or the mean EUM index during oxytocin administration and time to delivery., Conclusions: Uterine electrical activity as evaluated by EUM is significantly intensified following oxytocin administration, regardless of obstetrical characteristics, and is correlated with the baseline uterine electrical activity prior to oxytocin infusion.

Aim: We evaluated whether maintenance tocolysis (intravenous ritodrine hydrochloride and/or magnesium sulfate) was effective in cases of spontaneous preterm labor with intact membranes., Methods: One hundred and thirty preterm labor patients who reached 36 weeks of gestation by maintenance tocolysis were selected. Immediate delivery (ID) after ceasing maintenance tocolysis was defined as an 'effective case'. The correlated factors between ID and no immediate delivery (NID) were statistically analyzed., Results: Thirty-six patients delivered < two days after ceasing maintenance tocolysis (27.7%) and were defined as effective cases. Multiple logistic regression analysis revealed that amniotic fluid interleukin-8 at admission (≥ 2.3 ng/mL; odds ratio [OR] 5.6, 95% confidence interval [CI] 2.1-17.6; P < 0.001), pre-pregnancy body mass index (≤ 21.4; OR 5.3, 95% CI 2.0-16.2; P < 0.001) and cerclage (OR 3.6, 95% CI 1.1-11.8; P = 0.028) were independent factors correlated with ID (< 2 days)., Conclusion: Maintenance tocolysis may be effective in limited cases with mild intra-amniotic inflammation, in lean women and in cerclage cases. Maintenance tocolysis should be ceased in cases without these clinical factors when clinical symptoms disappear., (© 2017 Japan Society of Obstetrics and Gynecology.)

Cellular coupling of beta 3 -adrenoceptors (β 3 -ADR) to potassium channels in myometrium is largely unknown. In vitro study was undertaken to unravel the presence of β 3 -adrenergic receptors (ADR) and the role of K + -channels in mediating β 3 -ADR-induced relaxation in isolated myometrial strips from cyclic non-pregnant water buffaloes. Isometric tension was recorded in isolated myometrial strips using data acquisition system based physiograph. Compared to SR 59230A, BRL 37344 was found to be more potent in inducing β 3 -dependent myometrial relaxation which was significantly (p < 0.05) inhibited in the presence of β 3 antagonist, SAR 150640. The immunoreactive protein to β 3 -ADR was also detected in membrane fraction of myometrial protein. Further, incubation with BRL 37344 (10 μM) significantly (p < 0.05) increased c-AMP accumulation (37.58 ± 9.52 pmol/mg protein; n = 4) in the myometrial strips compared to basal c-AMP level (16.85 ± 3.87 pmol/mg protein; n = 4). The concentration response curves (CRC) of BRL 37344 were significantly (p < 0.05) shifted towards right in the presence of K ATP channels specific blocker, glibenclamide (10 μM) and maxi K + -channels (BK Ca ) specific blocker, iberiotoxin (100 nM), with decrease in both efficacy and potency as compared to control. However, 4-aminopyridine (4-AP), a specific blocker of the voltage gated K + -channels (Kv), failed to alter the CRC of BRL 37344. Existence of immunoreactive protein to Kir6.1, α-subunit of BK Ca and Kv1.1 channels were also detected in the membrane fraction of myometrial protein. Based on the above findings, it can be concluded that BRL 37344 is a potent stimulator of β 3 -adrenoceptors in buffalo myometrium and besides mediating their effect through rise in c-AMP, they are coupled to K ATP and BK Ca channels in inducing tocolytic effects., (Copyright © 2017 Elsevier Inc. All rights reserved.)

The non-canonical NF-κB signaling (RelB/p52) pathway drives pro-labor genes in the human placenta, including corticotropin-releasing hormone (CRH) and cyclooxygenase-2 (COX-2), making this a potential therapeutic target to delay onset of labor. Here we sought to identify small molecule compounds from a pre-existing chemical library of orally active drugs that can inhibit this NF-κB signaling, and in turn, human placental CRH and COX-2 production. We used a cell-based assay coupled with a dual-luciferase reporter system to perform an in vitro screening of a small molecule library of 1,120 compounds for inhibition of the non-canonical NF-κB pathway. Cell toxicity studies and drug efflux transport MRP1 assays were used to further characterize the lead compounds. We have found that 14 drugs have selective inhibitory activity against lymphotoxin beta complex-induced activation of RelB/p52 in HEK293T cells, several of which also inhibited expression of CRH and COX-2 in human term trophoblast. We identified sulfapyridine and propranolol with activity against CRH and COX-2 that deserve further study. These drugs could serve as the basis for development of orally active drugs to affect length of gestation, first in an animal model, and then in clinical trials to prevent preterm birth during human pregnancy.

Background: Pre-term birth is a major health care challenge throughout the world, and preterm labor represents a potentially reversible component of this problem. Current tocolytics do not improve preterm labor beyond 48 h. We have previously shown that anoctamin 1 (ANO1) channel blockade results in relaxation of pre-contracted human uterine smooth muscle (USM). Three drug classes with reported medicinal effects in humans also have members with ANO1 antagonism. In this study, we compared the ability of representatives from these 3 classes to reduce human USM contractility and excitability., Objective: This study sought to examine the comparative potency of 3 ANO1 antagonists on pregnant human USM relaxation, contraction frequency reduction, inhibition of intracellular calcium release and membrane hyperpolarization., Methods: Experiments were performed using: 1) Ex vivo organ bath (human pregnant tissue), 2) Oxytocin-induced calcium flux (in vitro human USM cells) and 3) Membrane potential assay (in vitro human USM cells)., Results: Benzbromarone (BB) demonstrated the greatest potency among the compounds tested with respect to force, frequency inhibition, reducing calcium elevation and depolarizing membrane potential., Conclusion: While all 3 ANO1 antagonists attenuate pregnant human uterine tissue contractility and excitability, BB is the most potent tocolytic drug. Our findings may serve as a foundation for future structure-function analyses for novel tocolytic drug development.

Background: Galetin 3,6-dimethyl ether (FGAL) is a flavonoid isolated from aerial parts of Piptadenia stipulacea. Previously, FGAL was shown to inhibit both carbachol- and oxytocin-induced phasic contractions in the rat uterus, which was more potent with oxytocin. Thus, in this study, we aimed to investigate the tocolytic action mechanism of FGAL on the rat uterus., Methods: Segments of rat uterus ileum were suspended in organ bath containing modified Locke-Ringer solution at 32 °C, bubbled with carbogen mixture under a resting tension of 1 g. Isotonic contractions were registered using kymographs and isometric contractions using force transducer., Results: FGAL was more potent in relaxing uterus pre-contracted with oxytocin than with KCl. Additionally, FGAL shifted oxytocin-induced cumulative contractions curves to the right in a non-parallel manner, with E max reduction, indicating a pseudo-irreversible noncompetitive antagonism of oxytocin receptors (OTR) or a downstream pathway target. Moreover, FGAL shifted CaCl 2 -induced cumulative contraction curves to the right in a non-parallel manner in depolarizing medium, nominally without Ca 2+ , with E max reduction, suggesting the inhibition of Ca 2+ influx through Ca V . The relaxant potency of FGAL was reduced by CsCl, a non-selective K + channel blocker, suggesting positive modulation of these channels. Furthermore, in presence of apamin, 4-aminopyridine, glibenclamide or 1 mM TEA + , the relaxant potency of FGAL was attenuated, indicating the participation of SK Ca , K V , K ATP and highlighting BK Ca . Aminophylline, a non-selective phosphodiesterase (PDE) blocker, did not affect the FGAL relaxant potency, excluding the modulation of cyclic nucleotide PDEs pathway by FGAL., Conclusion: Tocolytic effect of FGAL on rat uterus occurs by pseudo-irreversible noncompetitive antagonism of OTR and activation of K + channels, primarily BK Ca , leading to calcium influx reduction through Ca V .

Background: In the present study, we used Doppler velocimetry in the ophthalmic artery to evaluate the hemodynamic status of the intracranial vasculature. This is the first time in the literature that indices of ophthalmic artery Doppler sonography of women with preeclampsia were evaluated before and after the use of magnesium sulfate to prevent eclampsia., Case Presentation: Indices of ophthalmic artery Doppler sonography of six women with severe preeclampsia at 27 to 33 weeks of gestational age were evaluated before and after the use of magnesium sulfate (10 minutes, 30 minutes, and 60 minutes after the magnesium sulfate loading dosage. The patients' ages were 26 years (patient 01), 29 years (patient 02), 20 years (patient 03), 21 years (patient 04), 20 years (patient 05), and 19 years (patient 06). The ethnic group of patients 01 and 04 was white and the ethnic group of patients 02, 03, 05 and 06 was mulatto., Conclusions: The apparent increase in resistance index and pulsatility index values, although there is no statistical significance in this series of cases, and the decrease in peak ratio values after the administration of magnesium sulfate reflect an increase in the impedance to flow in the ophthalmic artery and consequently a reduction in cerebral perfusion after the use of magnesium sulfate. This may explain how magnesium sulfate protects women with severe preeclampsia against cerebral damage and prevents acute convulsions in these patients. We believe that this case series report may have a broader clinical impact across medicine because the mechanism of how magnesium sulfate can protect patients and prevent acute convulsions is controversial.

Aim: Our aim was to investigate the effect of the prophylactic use of vaginal progesterone on the latency period from the initiation of tocolytic therapy to delivery in twin pregnancies with preterm labor., Methods: This study was a secondary analysis of a randomized, double-blind, placebo-controlled trial of twin pregnancies in mothers who were exposed to a 200 mg vaginal progesterone ovule or a placebo ovule daily from 18 to 34 weeks gestation. Patients who were administered tocolysis with Atosiban because of preterm labor were included. The latency from tocolysis to delivery, mean gestational age at delivery and the rates of delivery within 48 h and within seven days were compared between progesterone and placebo groups., Results: The analysis included 27 women in the progesterone group and 30 in the placebo group. The baseline characteristics were similar between the groups. Overall, there were no differences in the latency period to delivery (17.54 ± 13.54 days and 21.58 ± 13.52 days; P = 0.289), rates of delivery within 48 h (14.8% and 6.7%; P = 0.40) or within seven days (29.64% and 23.3%; P = 0.76) or mean gestational age at delivery (32.53 ± 3.33 and 34.13 ± 2.87; P = 0.08) between the progesterone and placebo groups, respectively., Conclusions: Prophylactic use of 200 mg of vaginal progesterone does not influence the latency to delivery in women with twin pregnancies treated with tocolysis because of preterm labor., (© 2017 Japan Society of Obstetrics and Gynecology.)

Objectives: Evidence for the efficacy of atosiban in improving pregnancy outcomes among patients undergoing assisted reproductive technology (ART) remains inconsistent., Methods: The PubMed, EMBASE, and CNKI databases were searched using keywords such as 'atosiban', 'infertility', and 'ART'. Studies that explored the efficacy of atosiban in the field of ART for patients with embryo transfer (ET) were included if they evaluated pregnancy outcomes. Combing using subgroups and sensitivity analysis were conducted, and risk ratios (RRs), and 95% confidence intervals (CIs) were calculated., Results: Six studies were included. Atosiban treatment could improve pregnancy outcomes for all patients undergoing ET, especially for the subgroups of patients with repeated implantation failure (RIF) (implantation rate: RR = 1.806, 95% CI = 1.473-2.215; clinical pregnancy rate: RR = 1.725, 95% CI = 1.394-2.135; live birth rate: RR = 2.141, 95% CI = 1.494-3.068), as shown by the comparison with placebo or no-treatment groups. However, no statistical significance was detected in subgroups of patients undergoing their first or second ET cycle. In addition, no significant differences were observed in positive pregnancy tests, miscarriage rates, multiple pregnancy rates, or ectopic pregnancy rates., Conclusions: Supplementation with atosiban has a positive effect on ART and embryo transfer procedure, especially for women undergoing their third or more ET cycle.

Background: Although physiologic transition from rhythmic contractions to uterine retraction postpartum remains a poorly understood process, it has been shown that the latter is essential in the prevention of hemorrhage and its negative consequences., Objective: To investigate the transition from oscillatory contractions to tonic contracture in human myometrium after delivery, a mechanism purported to facilitate postpartum hemostasis. Protein kinase C (PKC) plays a key regulatory role in human uterine contractions because it can prevent dephosphorylation of regulatory proteins and sensitize the contractile machinery to low Ca 2+ . Thus, activation of PKC by phorbol 12,13-dibutyrate (PDBu) may act as a strong uterotonic agent., Study Design: Uterine biopsies were obtained from consenting women undergoing elective caesarian delivery at term without labor (N = 19). Isometric tension measurements were performed on uterine strips (n = 114). The amplitudes and area under the curve of phasic contractions and tonic responses were measured and compared. A total of 1 μM PDBu was added to the isolated organ baths, and maximal tension of the uterine contracture was determined in the absence and presence of either 1 μM of staurosporine, 100 nM nifedipine, or 10 μM cyclopiazonic acid to assess the role of PKC and calcium sensitivity on uterine contractility., Results: On the addition of PDBu on either basal or oxytocin-induced activity, consistent contractures were obtained concomitant with complete inhibition of phasic contractions. After a 30-minute incubation period, the mean amplitude of the PDBu-induced tone represented 65.3% of the amplitude of spontaneous contraction. Staurosporine, a protein kinase inhibitor, induced a 91.9% inhibition of PDBu contractures, a process not affected by nifedipine or cyclopiazonic acid, thus indicating that this mechanism is largely Ca 2+ independent., Conclusion: Pharmacologic activation of PKC leads to a significant contracture of the myometrium. Together, these data suggest that the up-regulation of PKC plays a physiologic role in the modulation of uterine contracture after delivery. A switch from phasic to strong tonic contractions potentially may facilitate postpartum hemostasis., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: In addition to its role as a circulating hormone, oxytocin can also act as a neurotransmitter and a neuromodulator within the brain. In this study, we investigated the intra-hippocampal effect of oxytocin on an experimental seizure model induced by pentylenetetrazole (PTZ) in rats. We also used atosiban (oxytocin antagonist), diazepam and flumazenil (gamma-aminobutyric acid or GABA-benzodiazepine receptor agonist and antagonist, respectively) to clarify the involved mechanism., Method: In ketamine-xylazine anesthetized rats, the right and left sides of the dorsal hippocampus (CA1) were implanted with two guide cannulas. Epileptic behaviors were induced by intraperitoneal (ip) injection of PTZ (60mg/kg), and the latency time to onset of first myoclonic jerk, and the duration of epileptic seizures were determined for 30min., Results: Intra-hippocampal microinjections of oxytocin at doses of 10 and 20ng/site, diazepam (100 and 200ng/site) and co-administration of their ineffective doses significantly (p<0.01) increased the onset of first myoclonic jerk and decreased duration of epileptic seizure. Antiepileptic effects of oxytocin (20ng/site) were inhibited by atosiban (20 and 40ng/site) and flumazenil (100 and 200ng/site) pretreatments. On the other hand, prior administration of flumazenil (100 and 200ng/site) and atosiban (20 and 40ng/site) prevented the antiepileptic effects induced by diazepam (100 and 200ng/site)., Conclusions: The results of the present study showed that at the level of the hippocampus oxytocin suppressed the severity of epileptic behaviors. A hippocampal GABA-benzodiazepine receptor mechanism may be involved in antiepileptic effect of oxytocin., (Copyright © 2017 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.)

Purpose: The purpose of this study was to determine the contractile patterns induced by oxytocin in myometrium exposed to magnesium sulfate (MgSO 4 ). We hypothesized that MgSO 4 pretreatment would reduce oxytocin-induced myometrial contractions in both oxytocin-naïve and oxytocin-desensitized myometrium., Methods: In this prospective in vitro study, myometrial samples were obtained from 26 women undergoing elective Cesarean deliveries. Samples were divided into six groups. Four groups were apportioned to no pretreatment (control group), oxytocin 10 -5 M pretreatment (desensitization group), MgSO 4 3.5 mM pretreatment, and MgSO 4 3.5 mM + oxytocin 10 -5 M pretreatment. This was followed by dose-response testing to oxytocin 10 -10 to 10 -5 M in all four groups. Two additional groups included MgSO 4 3.5 mM pretreatment and MgSO 4 3.5 mM + oxytocin 10 -5 M pretreatment, followed by dose-response testing to oxytocin along with MgSO 4 3.5 mM. The outcomes were motility index (MI), as defined by the amplitude (g) × frequency of myometrial contractions (c) over ten minutes, and area under the curve (AUC)., Results: In oxytocin-naïve myometrium, the mean (standard error [SE]) MI was not affected by MgSO 4 pretreatment [3.31 (0.20) √g⋅c/10 min] as compared with control (P = 0.88), even when MgSO 4 was continued during dose-response testing [2.50 (0.19) √g⋅c/10 min; P = 0.41]. In the oxytocin-desensitized model, mean (SE) MI was not affected by MgSO 4 pretreatment [2.60 (0.21) √g⋅c/10 min; P = 0.68], but when MgSO 4 was continued during the dose-response period, the MI was significantly reduced compared with control [1.89 (0.13) √g⋅c/10 min; P < 0.001]. The results for AUC were similar to MI, except for a significant reduction in oxytocin-naïve myometrium when MgSO 4 was continued during dose-response testing (P = 0.02)., Conclusion: Magnesium sulfate pretreatment does not impair oxytocin-induced myometrial contractility in oxytocin-naïve or desensitized myometrium unless it is continued during oxytocin dose-response testing. These results suggest that its tocolytic effect is likely dependent on an extracellular mechanism. The study was registered with ClinicalTrials.gov, number NCT02647268.

Objectives: Preeclampsia is characterised by systemic endothelial cell dysfunction thought to be triggered by toxic/dangerous factors from the placenta, including placental extracellular vesicles (EVs). Why placental EVs become toxic is unknown. We previously reported that preeclamptic sera produced toxic/dangerous placental macrovesicles but whether small EVs are also toxic/dangerous in preeclampsia is unknown., Study Design: First trimester placental explants were treated with 10% preeclamptic or control sera (n=10) for 24h. Micro- and nano-vesicles were harvested by sequential centrifugation. Micro- or nano-vesicles were also exposed to monolayers of endothelial cells in the presence or absence of nifedipine (50μg/ml) or labetalol (0.5μg/ml) which are well-known anti-hypertensives in clinical practices., Main Outcomes Measures: The number and size of micro- and nano-vesicles were counted. Endothelial cell-surface intercellular adhesion molecule 1 (ICAM-1) and high mobility group box 1 (HMGB1) levels in micro- or nano-vesicles were measured by immunoassays., Results: Neither the amount nor size of both micro- and nano-vesicles was different after treating placental explants with preeclamptic or control sera. The levels of HMGB1 were significantly increased in both micro- and nano-vesicles from preeclamptic sera treated placental explants (p<0.03). Exposing endothelial cells to micro- or nano-vesicles from preeclamptic sera-treated placental explants induced endothelial activation, but it was reversed by co-incubation with nifedipine (p=0.004) or labetalol (p=0.002)., Conclusion: Our data demonstrate that preeclamptic sera produce toxic/dangerous micro- and nano-placental EVs which activated endothelial cells. This effect was reversed by antihypertensives. The increased levels of HMGB1 in EVs may contribute to endothelial cell activation., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Aim: This quality Improvement study evaluated the applicability of our protocol for early-onset severe pre-eclampsia, prepared in April 2013., Methods: We collected data from all women with early-onset severe pre-eclampsia treated at our hospital between March 2008 and August 2015. Neonatal and maternal outcomes were compared between protocol-based (n = 17) and non-protocol-based management groups (n = 28)., Results: The latency period was significantly longer in the protocol-based than in the non-protocol-based group (21.9 ± 3.7 vs 11.0 ± 2.9 days). Gestational age at delivery was significantly more advanced in the protocol-based than in the non-protocol-based group (31.4 ± 0.6 vs 29.8 ± 0.4 weeks). Serious neonatal complications were significantly less prevalent in the protocol-based than in the non-protocol-based group (26% vs 79%). Among the protocol components, magnesium sulfate use was the only independent factor contributing to the absence of serious neonatal complications. The percentages of women exhibiting persistent proteinuria or hypertension at one, two and three months post-partum were similar between the groups., Conclusions: Strict adherence to our protocol improved neonatal outcomes without affecting maternal prognosis. Routine use of magnesium sulfate could be the most important component of the protocol., (© 2017 Japan Society of Obstetrics and Gynecology.)

Many pharmacological agents have been investigated to manage preterm labor; we postulate that a combination of tocolytic drugs may achieve a better effect in the prevention of uterine contractions without dose-dependent adverse effects. The aim of this study was to evaluate the inhibitory effect of dual combinations of tocolytics in vitro. Human myometrium was obtained during elective cesarean sections (term without labor; n = 40). Myometrial strips were placed in organ baths for the measurement of isometric tension. Contractile activity was induced by oxytocin (10 - 8 mol/L), then a concentration-response curve to single or dual combinations of tocolytics was started. All studied tocolytics (nifedipine, ritodrine, nitroglycerin, atosiban, and NS-1619), when used alone, significantly inhibited myometrial contractions. When combined, nifedipine plus ritodrine produced a significantly greater inhibition of contractility than each drug alone in the midrange of concentrations. The combination of nifedipine plus nitroglycerin or nifedipine plus atosiban produced a significantly greater inhibition than nitroglycerin or atosiban alone but not greater than nifedipine. The combination of nifedipine plus NS-1619 (Ca +2 -activated K + [BK Ca ] channel opener) reduced the inhibitory effect of each drug. We concluded that a selected combination of tocolytics (nifedipine plus ritodrine) produced a significantly greater inhibitory effect on contractility than each drug alone at intermediate concentrations. Thus, specific combinations of tocolytics with different intracellular signaling pathways may have a synergic effect constituting a provocative new option for preterm labor treatment.

Objective: To evaluate autonomic modulation of heart rate in pregnant women treated with oxytocin to induce labor and with atosiban (an oxytocin antagonist) to arrest preterm labor., Methods: A prospective study with two cohorts: 14 pregnant women treated with atosiban for premature uterine contractions, and 28 women undergoing induction of labor with oxytocin. Computerized analyses of the electrocardiogram were performed with spectral and nonlinear dynamic analyses., Results: Atosiban did not alter any of the variables associated with heart rate variability, whereas oxytocin showed a dose-dependent decrease in heart rate (p < 0.05) and a significant increase in all spectral variables studied (p < 0.01)., Conclusions: Atosiban has no adverse effects on the cardiovascular system or the modulation of heart rate. Oxytocin, on the other hand, can cause a dose-dependent bradycardic effect and an increase in the spectral power, thus should be used with caution in certain pregnant women.

Aim: Our aim is to evaluate the effect of nifedipine on fetoplacental hemodynamic parameters., Methods: A retrospective study was conducted at a tertiary center with 30 patients for whom nifedipine treatment was used as a tocolytic therapy for preterm labor. Initiation of this treatment was at 31.6±2.5 weeks of gestation. We combined the pulse Doppler imaging parameters with grayscale imaging via the Bernoulli theorem, which is called the "continuity equation", to get the fetoplacental perfusion (FPP). Evaluated parameters were the resistance index (RI), the pulsatility index (PI), systole/diastole ratios (S/D), the velocity-time integral of the umbilical artery (VTI), the radius of the umbilical artery, the peak systolic velocity and the mean pressure gradient in the umbilical artery. From these parameters, the FPP was acquired., Results: We found that the RI, the PI and the S/D ratio did not change after treatment with nifedipine. The mean pressure gradient, the VTI and the peak systolic velocity increased after treatment with nifedipine. Nifedipine increases FPP from 166±73.81 beat.cm3/min to 220±83.3 beat.cm3/min., Discussion: Although nifedipine had no effect on the PI, the RI or the S/D, it increased the mean pressure gradient, the VTI and FPP.

Background: Preterm birth at <37 weeks of gestation is the most common and costly complication of pregnancy and remains the leading cause of neonatal morbidity, death, and reduced achievement in surviving infants. Magnesium sulfate is 1 class of tocolytics for threatened preterm labor; however, its clinical efficacy has been questioned. Twin pregnancies are at increased risk of preterm delivery compared with singleton gestations, which suggests that there is twin-specific risk to preterm delivery in twins. The prevention strategies that are applied to singleton pregnancies, however, have not been shown to be effective in twin pregnancies., Objective: The purpose of this study was to compare the relaxant effect of magnesium sulfate on spontaneous and oxytocin-augmented contractions of human myometrium from singleton and twin pregnancies and to examine whether the effect of oxytocin on magnesium sulfate's potency could be reversed with the use of the oxytocin receptor antagonist, atosiban., Study Design: Myometrium was obtained at the time of prelabor cesarean section (36-40 weeks of gestation) from women with singleton (n=23) or twin (n=12) pregnancy. Isometric tension recordings were made on myometrial strips that were mounted in organ baths that were superfused with physiologic saline solution. Strips were exposed to rising concentrations of magnesium sulfate, and the effect on spontaneous contractions or stimulated with oxytocin (0.5 nmol/L) and in the presence or absence of atosiban (100 nmol/L) was recorded. The contractile characteristics after each application of magnesium sulfate, which included amplitude of contraction and activity integral, were measured. Concentration-response curves were fitted with the use of nonlinear regression and comparison of the negative logarithm of the 50% reduction in activity values., Results: Magnesium sulfate exerted an equal concentration-dependent inhibitory effect on spontaneous myometrial contractions from both singleton and twin myometrium (P>.05). The application of oxytocin produced a significant rightward shift in the concentration-response curves (P<.0001), but no differences were found between pregnancy groups (P>.05). The addition of atosiban shifted concentration-response curves significantly back to the left for amplitude of contraction and activity integral in singletons (P<.0001). However, only activity integral was significantly reversed in twins (P<.01)., Conclusion: Magnesium sulfate is equipotent in suppressing contractions in singleton and twin myometrium. Oxytocin (0.5 nmol/L) significantly reduces the tocolytic potency of magnesium sulfate, which may explain, in part, magnesium sulfate's poor efficacy in vivo; however, this can be reversed partially by the use of an oxytocin receptor antagonist. Combination tocolysis that involves oxytocin receptor antagonists requires further investigation., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Objective: The potency of acute montelukast treatment, a leukotriene receptor antagonist, has been demonstrated as tocolytic on in vitro myometrial contractility. This study assessed the ability of a 48h montelukast treatment to modify in vitro contractions under inflammatory conditions in a pregnant rat model., Study Design: Pregnant Sprague-Dawley rats were injected intraperitoneally (gestational days 20-22) with lipopolysaccharides (LPS) 200μg/kg (4 treatments at 12h intervals) alone or combined with montelukast 10mg/kg/day or a saline solution for a 48h period. Uterine rings (n=72) were obtained by median laparotomy at day 22. Spontaneous contractile activities were compared using pharmacological compounds (oxytocin, nifedipine) along with assessment of contractile parameters. Myometrial subcellular fractions were also analyzed by Western blot to quantify oxytocin, cysteinyl leukotriene receptors and inflammation markers., Results: In in vitro experiments, the area under the curve, the amplitude and the duration of phasic contractions were significantly reduced following 48h of LPS+montelukast treatment comparatively to the LPS group. Moreover, in this same group, oxytocin (10 -9 -10 -7 M) largely decreased uterine sensitivity (p=0.04). Following LPS and montelukast treatment, the tocolytic effectiveness of nifedipine (10 -9 -10 -7 M) was increased (p<0.01). Western blot analysis confirmed the presence of type 1 CysLT receptors in all treated groups. Hence, montelukast treatment restored TNF-α and COX-2 basal levels., Conclusion: Our results strongly suggest that montelukast treatment could facilitate a relative uterine quiescence by decreasing its sensitivity to uterotonic agent or by increasing tocolytic efficiency under proinflammatory conditions., (Published by Elsevier Ireland Ltd.)

Preterm labor caused by uterine contractions is a major contributor to neonatal morbidity and mortality. Treatment intended to reduce uterine contractions include tocolytic agents, such as indomethacin. Unfortunately, clinically used tocolytics are frequently inefficient and cross the placenta causing fetal side effects. Here we show for the first time in obstetrics the use of a targeted nanoparticle directed to the pregnant uterus and loaded with a tocolytic for reducing its placental passage and sustaining its efficacy. Nanoliposomes encapsulating indomethacin and decorated with clinically used oxytocin receptor antagonist were designed and evaluated in-vitro, ex-vivo and in-vivo. The proposed approach resulted in targeting uterine cells in-vitro, inhibiting uterine contractions ex-vivo, while doubling uterine drug concentration, decreasing fetal levels, and maintaining the preterm birth rate in vivo in a pregnant mouse model. This promising approach opens new horizons for drug development in obstetrics that could greatly impact preterm birth, which currently has no successful treatments.

Background: Premature cervical remodeling resulting in spontaneous preterm birth may begin with premature failure or relaxation at the internal os (termed "funneling"). To date, we do not understand why the internal os fails or why funneling occurs in some cases of premature cervical remodeling. Although the human cervix is thought to be mostly collagen with minimal cellular content, cervical smooth muscle cells are present in the cervix and can cause cervical tissue contractility., Objective: To understand why the internal os relaxes or why funneling occurs in some cases of premature cervical remodeling, we sought to evaluate cervical smooth muscle cell content and distribution throughout human cervix and correlate if cervical smooth muscle organization influences regional cervical tissue contractility., Study Design: Using institutional review board-approved protocols, nonpregnant women <50 years old undergoing hysterectomy for benign indications were consented. Cervical tissue from the internal and external os were immunostained for smooth muscle cell markers (α-smooth muscle actin, smooth muscle protein 22 calponin) and contraction-associated proteins (connexin 43, cyclooxygenase-2, oxytocin receptor). To evaluate cervical smooth muscle cell morphology throughout the entire cervix, whole cervical slices were obtained from the internal os, midcervix, and external os and immunostained with smooth muscle actin. To correlate tissue structure with function, whole slices from the internal and external os were stimulated to contract with 1 μmol/L of oxytocin in organ baths. In separate samples, we tested if the cervix responds to a common tocolytic, nifedipine. Cervical slices from the internal os were treated with oxytocin alone or oxytocin + increasing doses of nifedipine to generate a dose response and half maximal inhibitory concentration. Student t test was used where appropriate., Results: Cervical tissue was collected from 41 women. Immunohistochemistry showed cervical smooth muscle cells at the internal and external os expressed mature smooth muscle cell markers and contraction-associated proteins. The cervix exhibited a gradient of cervical smooth muscle cells. The area of the internal os contained 50-60% cervical smooth muscle cells that were circumferentially organized in the periphery of the stroma, which may resemble a sphincter-like pattern. The external os contained approximately 10% cervical smooth muscle cells that were randomly scattered in the tissue. In organ bath studies, oxytocin stimulated the internal os to contract with more than double the force of the external os (1341 ± 693 vs 523 ± 536 integrated grams × seconds, respectively, P = .009). Nifedipine significantly decreased cervical tissue muscle force compared to timed vehicle control (oxytocin alone) at doses of 10(-5) mol/L (vehicle 47% ± 15% vs oxytocin + nifedipine 24% ± 16%, P = .007), 10(-4) mol/L (vehicle 46% ± 16% vs oxytocin + nifedipine -4% ± 20%, P = .003), and 10(-3) mol/L (vehicle 42% ± 14% vs oxytocin + nifedipine -15% ± 18%, P = .0006). The half maximal inhibitory concentration for nifedipine was 1.35 × 10(-5) mol/L., Conclusion: Our findings suggest a new paradigm for cervical tissue morphology-one that includes the possibility of a specialized sphincter at the internal os. This new paradigm introduces novel avenues to further investigate potential mechanisms of normal and premature cervical remodeling., (Copyright © 2016 Elsevier Inc. All rights reserved.)