Impacts of Tocolytics on Maternal and Neonatal Glucose Levels in Women With Gestational Diabetes Mellitus.

BACKGROUND: We investigated the impacts of tocolytic agents on maternal and neonatal blood glucose levels in women with gestational diabetes mellitus (GDM) who used tocolytics for preterm labor. METHODS: This multi-center, retrospective cohort study included women with GDM who were admitted for preterm labor from twelve hospitals in South Korea. We excluded women with multiple pregnancies, anomalies, overt DM diagnosed before pregnancy or 23 weeks of gestation, and women who received multiple tocolytics. The patients were divided according to the types of tocolytics; atosiban, ritodrine, and nifedipine group. We collected baseline maternal characteristics, pregnancy outcomes, maternal glucose levels during hospitalization, and neonatal glucose levels. We compared the frequency of maternal hyperglycemia and neonatal hypoglycemia among three groups. A multivariate logistic regression analysis was performed to evaluate the contributing factors to the occurrence of maternal hyperglycemia and neonatal hypoglycemia. RESULTS: A total of 128 women were included: 44 (34.4%), 51 (39.8%), and 33 (25.8%) women received atosiban, ritodrine, and nifedipine, respectively. Mean fasting blood glucose (FBG) (112.3, 109.6, and 89.5 mg/dL, P < 0.001) and 2-hour postprandial glucose (PPG2) levels (145.4, 148.3, and 116.5 mg/dL, P = 0.004) were significantly higher in atosiban and ritodrine group than those in nifedipine group. Even after adjusting for covariates including antenatal steroid use, gestational age at admission, and pre-pregnancy body mass index, there was an increased risk of high maternal mean FBG (≥ 95 mg/dL) and PPG2 (≥ 120 mg/dL) levels in the atosiban and ritodrine group than in nifedipine group. The atosiban and ritodrine groups are also at increased risk of neonatal hypoglycemia (< 47 mg/dL) compared to the nifedipine group with the odds ratio of 4.58 and 4.67, respectively (P < 0.05). CONCLUSION: There is an increased risk of maternal hyperglycemia and neonatal hypoglycemia in women with GDM using atosiban and ritodrine tocolytics for preterm labor compared to those using nifedipine.

Atosiban versus placebo in the treatment of threatened preterm birth between 30 and 34 weeks gestation: study protocol of the 4-year APOSTEL 8 follow-up.

INTRODUCTION: Currently, the majority of women worldwide with threatened preterm birth are treated with tocolytics. Although tocolytics can effectively delay birth for 48 hours, no tocolytic drug has convincingly been shown to improve neonatal outcomes and effects on long-term child development are unknown. The aim of this follow-up study of a placebo controlled randomised trial is to investigate the long-term effects of atosiban administration in case of threatened preterm birth on child's neurodevelopment and behaviour development, overall health and mortality. METHODS AND ANALYSIS: This protocol concerns a follow-up study of the multicentre randomised double-blind placebo controlled APOSTEL 8 trial (NL61439.018.17, EudraCT-number 2017-001007-72). In this trial, women with threatened preterm birth (between 30 and 34 weeks of gestation) defined as uterine contractions with (1) a cervical length of <15 mm or (2) a cervical length of 15-30 mm and a positive fibronectin test or (3) in centres where cervical length measurement is not part of the local protocol: a positive fibronectin test or Actim-Partus test or (4) ruptured membranes, are randomised to atosiban or placebo for 48 hours. The primary outcome is a composite of perinatal mortality and severe neonatal morbidity. Children born to mothers who participated in the APOSTEL 8 study (n=760) will be eligible for follow-up at 4 years of corrected age and assessed using four parent-reported questionnaires. Primary outcomes are neurodevelopment and behaviour problems. Secondary outcomes are on child growth and general health. All outcomes will be compared between the atosiban and placebo group with OR and corresponding 95% CI. Analyses will be performed using the intention-to-treat approach. ETHICS AND DISSEMINATION: The Medical Research Ethics Committee from Amsterdam UMC confirmed that de Medical Research Involving Human Subjects Act (Dutch WMO-law) did not apply to our study (W21_386 # 21.431). Results will be published in a peer-reviewed journal and shared with stakeholders and participants. This protocol is published before analysis of the results.

Atosiban interacts with growth hormones as adjuvants in frozen-thawed embryo transfer cycles.

Objective: To investigate the interaction between atosiban and growth hormone (GH) as adjuvants in frozen-thawed embryo transfer (FET) cycles. Method: A total of 11627 patients who underwent FET at Xiamen University Affiliated Chenggong Hospital between January 2018 to December 2022 were retrospectively analyzed. Among them, 482 patients received atosiban and 275 patients received GH. The interactions were estimated by comparing the odds ratio (OR) for pregnancy comparing patients with or without atosiban adjuvant in cohorts stratified according to the presence of GH use in either the overall cohort or a propensity score (PS) matched cohort. An interaction term (atosiban × GH) was introduced to a multivariate model to calculate the ratio of OR (ORR) adjusted for confounders. Results: For all patients receiving atosiban administration, no obvious effect on pregnancy was observed in comparison with either matched or unmatched controls. However, when the patients were stratified according to GH administration, atosiban showed a significant association with clinical pregnancy in comparison with either matched or unmatched controls among patients with GH treatment with rate ratios (RR) of 1.32 (95%CI: 1.05,1.67) and 1.35 (95%CI: 1,1.82), respectively. On the other hand, however, the association was absent among patients without GH treatment. The adjusted ORRs in both matched and unmatched cohorts were 2.44 (95%CI: 1.07,5.84) and 1.95 (95%CI: 1.05, 3.49) respectively. Conclusion: The combination use of atosiban and GH in FET cycles is potentially beneficial to the pregnancy. However, indications for the use of atosiban and GH may need further assessment.

Administration of Atosiban, an oxytocin receptor antagonist, ameliorates autistic-like behaviors in a female rat model of valproic acid-induced autism.

Autism spectrum disorder (ASD) is a pervasive developmental disorder with gender differences. Oxytocin (OXT) is currently an important candidate drug for autism, but the lack of data on female autism is a big issue. It has been reported that the effect of OXT is likely to be different between male and female ASD patients. In the study, we specifically explored the role of the OXT signaling pathway in a VPA-induced female rat's model of autism. The data showed that there was an increase of either oxytocin or its receptor expressions in both the hippocampus and the prefrontal cortex of VPA-induced female offspring. To determine if the excess of OXT signaling contributed to autism symptoms in female rats, exogenous oxytocin and oxytocin receptor antagonists Atosiban were used in the experiment. It was found that exogenous oxytocin triggered autism-like behaviors in wild-type female rats by intranasal administration. More interestingly, several autism-like deficits including social interaction, anxiety, and repeat stereotypical sexual behavior in the VPA female offspring were significantly attenuated by oxytocin receptor antagonists Atosiban. Moreover, Atosiban also effectively improved the synaptic plasticity impairment induced by VPA in female offspring. Our results suggest that oxytocin receptor antagonists significantly improve autistic-like behaviors in a female rat model of valproic acid-induced autism.

The oxytocin antagonist cligosiban reduces human prostate contractility: Implications for the treatment of benign prostatic hyperplasia.

BACKGROUND AND PURPOSE: With increasing life expectancy, benign prostatic hyperplasia (BPH) consequently affects more ageing men, illustrating the urgent need for advancements in BPH therapy. One emerging possibility may be the use of oxytocin antagonists to relax smooth muscle cells in the prostate, similar to the currently used (although often associated with side effects) α1-adrenoceptor blockers. EXPERIMENTAL APPROACH: For the first time we used live-imaging, combined with a novel image analysis method, to investigate the multidirectional contractions of the human prostate and determine their changes in response to oxytocin and the oxytocin antagonists atosiban and cligosiban. Human prostate samples were obtained and compared from patients undergoing prostatectomy due to prostate cancer as well as from patients with transurethral resection of prostate tissue due to severe BPH. KEY RESULTS: The two cohorts of tissue samples showed spontaneous multidirectional contractions, which significantly increased after the addition of oxytocin. Different to atosiban, which showed ambiguous effects of short duration, only long-acting cligosiban reliably prevented, as well as counteracted, any contractile oxytocin effect. Furthermore, cligosiban visibly reduced not only oxytocin-induced contractions, but also showed intrinsic activity to relax prostatic tissue. CONCLUSION AND IMPLICATIONS: Thus, the oxytocin antagonist cligosiban could be an interesting candidate in the search for novel BPH treatment options.

Bryophyllum pinnatum Inhibits Oxytocin and Vasopressin Signaling in Myometrial Cells.

The medicinal plant Bryophyllum pinnatum was previously shown to block oxytocin (OT)-induced signals in myometrial cells, consistent with its tocolytic effect observed in patients. OT activates not only OT receptors but also V1A receptors, two receptors with high receptor homology that are both expressed in the myometrium and play a crucial role in myometrial contraction signaling. We aimed to study the molecular pharmacology of B. pinnatum herbal preparations using specific receptor ligands, the human myometrial cell line hTERT-C3, and cell lines expressing recombinant human OT and V1A receptors.We found that press juice from B. pinnatum (BPJ) inhibits both OT- and vasopressin (AVP)-induced intracellular calcium increases in hTERT-C3 myometrial cells. In additional assays performed with cells expressing recombinant receptors, BPJ also inhibited OT and V1A receptor-mediated signals with a similar potency (IC50 about 0.5 mg/mL). We further studied endogenous OT- and AVP-sensitive receptors in hTERT-C3 cells and found that OT and AVP stimulated those receptors with similar potency (EC50 of ~ 1 nM), suggesting expression of both receptor subtypes. This interpretation was corroborated by the antagonist potencies of atosiban and relcovaptan that we found. However, using qPCR, we almost exclusively found expression of OT receptors suggesting a pharmacological difference between recombinant OT receptors and native receptors expressed in hTERT-C3 cells.In conclusion, we show that B. pinnatum inhibits both OT and AVP signaling, which may point beyond its tocolytic effects to other indications involving a disbalance in the vasopressinergic system.

Comparison of terbutaline and atosiban as tocolytic agents in intrauterine repair of myelomeningocele: a retrospective cohort study.

BACKGROUND: Myelomeningocele (MMC) is a neural tube defect disease. Antenatal repair of fetal MMC is an alternative to postnatal repair. Many agents can be used as tocolytics during the in utero fetal repair such as ß2-agonists and oxytocin receptor antagonists, with possible maternal and fetal repercussions. This study aims to compare maternal arterial blood gas analysis between terbutaline or atosiban, as tocolytic agents, during intrauterine MMC repair. METHODS: Retrospective cohort study. Patients were divided into two groups depending on the main tocolytic agent used during intrauterine MMC repair: atosiban (16) or terbutaline (9). Maternal arterial blood gas samples were analyzed on three moments: post induction (baseline, before the start of tocolysis), before extubation, and two hours after the end of the surgery. RESULTS: Twenty-five patients were included and assessed. Before extubation, the terbutaline group showed lower arterial pH (7.347 ± 0.05 vs. 7.396 ± 0.02 for atosiban, p = 0.006) and higher arterial lactate (28.33 ± 12.76 mg.dL-1 vs. 13.06 ± 6.35 mg.dL-1, for atosiban, p = 0.001) levels. CONCLUSIONS: Patients who received terbutaline had more acidosis and higher levels of lactate, compared to those who received atosiban, during intrauterine fetal MMC repair.

Effects of atosiban on clinical outcome in frozen-thawed embryo transfer: a propensity score matching study.

PURPOSE: To evaluate the effects of atosiban on clinical outcomes in patients undergoing frozen-thawed embryo transfer. METHODS: The clinical data of 1093 infertile patients who underwent frozen-thawed embryo transfer in our center from January 2019 to December 2020 were retrospectively analyzed (control, 418; atosiban, 675). Propensity score matching (PSM) analysis identified 400 matched pairs of patients. The implantation rate, clinical pregnancy rate, live birth rate, biochemical pregnancy rate, abortion rate, multiple pregnancy rate, and ectopic pregnancy rate between the two groups were compared. RESULTS: Before PSM, patients differed by infertility factors, number of transferred embryos, and endometrial preparation protocol (P < 0.05). After PSM, characteristics were similar in corresponding patients of the atosiban and control groups. After propensity score matching, we found that there was no significant difference in the implantation rate, clinical pregnancy rate, live birth rate, biochemical pregnancy rate, abortion rate, multiple pregnancy rate, and ectopic pregnancy rate in atosiban and control group (P > 0.05). CONCLUSION: Atosiban did not improve the clinical outcomes of infertile patients with frozen-thawed embryo transfer.

A randomized double blind comparison of atosiban in patients with recurrent implantation failure undergoing IVF treatment.

BACKGROUND: Patients with recurrent implantation failure (RIF) may have more uterine contractions. Several observational studies suggested that atosiban administration around embryo transfer resulted in higher pregnancy rates in RIF patients. This study aimed to evaluate the effect of atosiban given before fresh embryo transfer on pregnancy outcomes of women with RIF. METHODS: A prospective, randomized, double-blind controlled clinical trial was performed in IVF center of Shanghai First Maternity and Infant Hospital. According to a computer-generated randomization list, 194 infertile women with RIF received fresh embryo transfer between July 2017 and December 2019 were randomly allocated into the atosiban (n = 97) and the placebo (n = 97) groups. Women in the treatment group received atosiban intravenously about 30 min before embryo transfer with a bolus dose of 6.75 mg over one minute. Those in the placebo group received only normal saline infusion for the same duration. RESULTS: There was no significant difference in the live birth rate between the atosiban and placebo groups (42.3% vs 35.1%, P = 0.302, RR = 1.206 (0.844-1.723)). No significant differences were found between the two groups in the positive pregnancy test, clinical pregnancy, ongoing pregnancy, miscarriage, multiple pregnancy, ectopic pregnancy and implantation rates. Similar results were found when stratified by the number of embryos previously transferred, number of previous failed embryo transfers, frequency of endometrial peristalsis on embryo transfer day (≥ 3 waves/min) or serum estradiol (E2) on the day of hCG above the median level. And, there was no correlation between the serum E2 level on the day of hCG and the frequency of endometrial peristalsis on embryo transfer day. The frequency of endometrial peristalsis on embryo transfer day, total FSH/HMG dosage and duration were the significant factors which independently predicted the likelihood of a live birth. CONCLUSIONS: These results suggested that atosiban treatment before fresh embryo transfer might not improve the live birth rate in RIF patients. TRIAL REGISTRATION: The study had been approved by the Institutional Review Board of the hospital (2017 ethics No.43) and was registered under Clinicaltrials.gov with an identifier NCT02893722.

Simulated Y-site compatibility of atosiban acetate with selected intravenous drugs.

OBJECTIVE: The physical compatibility of atosiban and selected drugs during simulated Y-site administration was evaluated. We also searched for any compatibility predictions regarding its physicochemical properties. STUDY DESIGN: Test admixtures were prepared by mixing 5 mL of each study drug solution with 5 mL of atosiban solution in a 1:1 ratio to simulate Y-site infusion. Assessments were made immediately after mixing (baseline), and at 0.5, 1, and 3 h. Visual incompatibility was defined as a presence of haze or any visible particulate matter, gas formation, or colour change. Turbidity and pH variation of the admixtures were also assessed using instrumental methods. RESULTS: None of the admixtures used with atosiban exhibited visual changes and no incompatibility regarding instrumental methods were observed, because no admixture had an increase of 0.5 nephelometric turbidity units, and no pH change was above one unit when compared to baseline. However, the pH of ampicillin and omeprazole admixtures fell outside of the atosiban stability range. CONCLUSIONS: Our study showed no physical incompatibility between atosiban and the test drugs in terms of visual changes or nephelometric and pH measurements. However, we recommend against atosiban and ampicillin or omeprazole coadministration until complementary compatibility studies are performed.

Tocolysis with nifedipine versus atosiban and perinatal outcome: an individual participant data meta-analysis.

BACKGROUND: Worldwide, nifedipine and atosiban are the two most commonly used tocolytic agents for the treatment of threatened preterm birth. The aim of this study was to evaluate the effectiveness of nifedipine and atosiban in an individual participant data meta-analysis (IPDMA). METHODS: We investigated the occurrence of adverse neonatal outcomes in women with threatened preterm birth by performing an IPDMA, and sought to identify possible subgroups in which one treatment may be preferred. We searched PubMed, Embase, and Cochrane for trials comparing nifedipine and atosiban for treatment of threatened preterm birth between 240/7 and 340/7 weeks' gestational age. Primary outcome was a composite of perinatal mortality and neonatal morbidities including respiratory distress syndrome, intraventricular haemorrhage, periventricular leucomalacia, necrotising enterocolitis, and sepsis. Secondary outcomes included NICU admission, prolongation of pregnancy and GA at delivery. For studies that did not have the original databases available, metadata was used. This led to a two-stage meta-analysis that combined individual participant data with aggregate metadata. RESULTS: We detected four studies (N = 791 women), of which two provided individual participant data (N = 650 women). The composite neonatal outcome occurred in 58/364 (16%) after nifedipine versus 69/359 (19%) after atosiban (OR 0.76, 95%CI 0.47-1.23). Perinatal death occurred in 14/392 (3.6%) after nifedipine versus 7/380 (1.8%) after atosiban (OR 2.0, 95%CI 0.80-5.1). Nifedipine results in longer prolongation of pregnancy, with a 18 days to delivery compared with 10 days for atosiban (HR 0.83 (96% CI 0.69-0.99)). NICU admission occurred less often after nifedipine (46%) than after atosiban (59%), (OR 0.32, 95%CI 0.14-0.75). The sensitivity analysis revealed no difference in prolongation of pregnancy for 48 hours (OR 1.0, 95% CI 0.73-1.4) or 7 days (OR 1.3, 95% CI 0.85-5.8) between nifedipine and atosiban. There was a non-significant higher neonatal mortality in the nifedipine-exposed group (OR 1.4, 95% CI 0.60-3.4). CONCLUSIONS: In this IPDMA, we found no differences in composite outcome between nifedipine and atosiban in the treatment of threatened preterm birth. However, the non-significant higher mortality after administering nifedipine warrants further investigation of the use of nifedipine as a tocolytic drug. STUDY REGISTRATION: We conducted this study according to a prospectively prepared protocol, registered with PROSPERO (the International Prospective Register of Systematic Reviews) under CRD42016024244.

Synergistic antitumor activity of 5-fluorouracil and atosiban against microsatellite stable colorectal cancer through restoring GATA3.

Clinically, 5-fluorouracil (5-Fu) is a first-line drug for the treatment of patients with colorectal cancer (CRC). However, chemoresistance to 5-Fu-based chemotherapy is a leading obstacle in achieving effective treatment for CRC, especially microsatellite stable (MSS) CRC. Since the cytotoxicity of 5-Fu is negatively correlated with oxytocin receptor (OXTR) expression in MSS CRC cell lines, our current study aimed to investigate the synergistic antitumor activity of 5-Fu combined with atosiban, an antagonist of OXTR. Our results suggested that atosiban remarkably potentiated the inhibitory effect of 5-Fu on the growth of MSS-type CRC cells in vitro and in vivo. Moreover, 5-Fu induced GATA3 in MSS CRC cells and tumors, which were eradicated by atosiban. Further investigation showed that atosiban strengthened the antitumor activity of 5-Fu through eradiation of 5-Fu-induced GATA3 in MSS-type CRC cells. Taken together, our findings suggest that atosiban potentiates the antitumor effect of 5-Fu by abolishing 5-Fu-induced GATA3, which provides a novel therapeutic strategy for MSS-type CRC via the combination of atosiban and 5-Fu.

Production of Atosiban's Key Intermediate Pentapeptide: Synthetic Approaches to the Development of a Peptide Synthesis with Less Racemization and Simplifier Purification Process.

The key intermediate NH2-Ile-Thr(Bzl)-Asn-Cys(Bzl)-Pro-COOH of Atosiban was prepared from N-Boc-S-Bzl-cysteine by the stepwise lengthening of the chain according to the repetitive N,O-bis(trimethylsilyl)acetamide/N-hydroxysuccinimide ester (BSA/NHS) strategy. This synthetic route required no chromatography purification and can be readily performed, yielding a highly pure pentapeptide compound.

Atosiban versus ritodrine as tocolytics in external cephalic version.

OBJECTIVE: To assess the efficacy of atosiban versus ritodrine as tocolytics in external cephalic version (ECV). MATERIALS AND METHODS: A prospective comparative trial was carried out in a tertiary hospital. 430 women with singleton breech pregnancies ≥36 weeks were recruited for ECV, 215 with ritodrine and 215 with atosiban as tocolytic agents. The efficacy, complications and perinatal outcomes were compared between both groups. The associations between variables were analyzed using the chi-square test (χ2) (qualitative), Student's t test (quantitative, parametric) or Mann-Whitney test (nonparametric). Statistical significance was established as p < .05. RESULTS: The overall ECV success rate was 47.9% (206/430), 46.0% in the atosiban group (99/215) and 49.8% in the ritodrine group (107/215). This difference showed no statistical significance (p = .440). A higher rate of uterine contractions after the maneuver was observed in the atosiban group (34.4 versus 22.8%; p = .008), but without clinical relevance. Perinatal outcomes were similar in both groups, with no significant differences. CONCLUSION: Atosiban and ritodrine showed similar efficacy as tocolytic agents in ECV, with no differences in complications and perinatal outcomes between these two agents.

Effects of atosiban on uterine peristalsis following frozen embryo transfer: A randomized controlled trial.

OBJECTIVES: To compare the effects of atosiban (oxytocin antagonist) on uterine peristalsis and pregnancy outcomes in the frozen embryo transfer (FET) cycle. SETTING: Srinagarind Hospital, a university hospital, Khon Kaen, Thailand. DESIGN: A randomized, double-blinded, controlled trial. METHODS: Fifty infertile women were randomized into the atosiban (n = 25) and placebo group (n = 25). Women in the study group received intravenous atosiban 6.75 mg, 30 min before embryo transfer, and continued infusion at 18 mg/h for 1 h. The dose was reduced to 6 mg/h for another 2 h. Saline solution was applied in the placebo group. The uterine peristalsis frequency was measured by transvaginal ultrasound 30 min before and 3 h after the embryo transfer. RESULTS: The respective mean baseline uterine peristalsis frequency (time) in the atosiban and placebo group was 10.3 ± 2.4 and 9.2 ± 3.4. The respective duration of uterine peristalsis in the atosiban and placebo group after receiving the intervention was reduced to 7.9 ± 2.1 and 6.9 ± 2.7. The implantation rate and clinical pregnancy rate were not statistically significant different between atosiban group and placebo group (37.5% versus 31.0%, RR 1.21, 95%CI: 0.60-2.44 and 44% versus 36%, RR 1.22, 95%CI: 0.62-2.42, respectively). Subgroup analysis indicated that the clinical pregnancy rate in those >35 years of age was not significantly different between both groups (31.6% and 18.8 %, RR 1.68, 95%CI: 0.50-5.68). CONCLUSION: Adding atosiban in FET did not reduce uterine peristalsis but may benefit the advanced age group.

Short-Term Outcomes of Atosiban in the Treatment of Preterm Labour at the Sultan Qaboos University Hospital, Muscat, Oman: A tertiary care experience.

OBJECTIVES: This study aimed to generate baseline evidence regarding the effectiveness of atosiban in delaying delivery by ≥48 hours among pregnant women presenting with threatened preterm labour (TPL). The secondary objective was to assess the relationship between atosiban success and various perinatal factors and neonatal outcomes. METHODS: This retrospective study was conducted between June 2008 and May 2018 at the Sultan Qaboos University Hospital, Muscat, Oman. The medical records of all pregnant women who received atosiban between 24-34 gestational weeks for TPL during this period were reviewed. RESULTS: A total of 159 women were included in the study. Atosiban was successful in delaying delivery by ≥48 hours in 130 cases (81.8%). Approximately half of the women (50.9%) achieved uterine quiescence in <12 hours. Failure to delay delivery by ≥48 hours was significantly lower among women with normal versus abnormal cervical findings (11.1% versus 25.6%; P = 0.023). Only 9.4% of women experienced minor side-effects. Mean birth weight (2,724.55 versus 1,707.59 g; P <0.001) and Apgar scores at 5 minutes (9.66 versus 8.28; P <0.001) were significantly higher among neonates delivered at ≥48 versus <48 hours post-atosiban, whereas the rate of neonatal respiratory distress syndrome was significantly lower (18.4% versus 81.6%; P <0.001). CONCLUSION: Atosiban was highly effective in delaying delivery by ≥48 hours and resulted in few adverse maternal side-effects and neonatal outcomes. To the best of the authors' knowledge, this is the first study conducted in Oman to evaluate the effectiveness of atosiban in preventing preterm labour.

A functional selective effect of oxytocin secreted under restraint stress in rats.

Restraint stress (RS) is an unavoidable stress model that triggers activation of the autonomic nervous system, endocrine activity, and behavioral changes in rodents. Furthermore, RS induces secretion of oxytocin into the bloodstream, indicating a possible physiological role in the stress response in this model. The presence of oxytocin receptors in vessels and heart favors this possible idea. However, the role of oxytocin secreted in RS and effects on the cardiovascular system are still unclear. The aim of this study was to analyze the influence of oxytocin on cardiovascular effects during RS sessions. Rats were subjected to pharmacological (blockade of either oxytocin, vasopressin, or muscarinic receptors) or surgical (hypophysectomy or sinoaortic denervation) approaches to study the functional role of oxytocin and its receptor during RS. Plasma levels of oxytocin and vasopressin were measured after RS. RS increased arterial pressure, heart rate, and plasma oxytocin content, but not vasopressin. Treatment with atosiban (a Gi biased agonist) inhibited restraint-evoked tachycardia without affecting blood pressure. However, this effect was no longer observed after sinoaortic denervation, homatropine (M2 muscarinic antagonist) treatment or hypophysectomy, indicating that parasympathetic activation mediated by oxytocin secreted to the periphery is responsible for blocking the increase in tachycardic responses observed in the atosiban-treated group. Corroborating this, L-368,899 (oxytocin antagonist) treatment showed an opposite effect to atosiban, increasing tachycardic responses to restraint. Thus, this provides evidence that oxytocin secreted to the periphery attenuates tachycardic responses evoked by restraint via increased parasympathetic activity, promoting cardioprotection by reducing the stress-evoked heart rate increase.

Atosiban Combined with Ritodrine for Late Threatened Abortion or Threatened Premature Labor Patients with No Response to Ritodrine: A Clinical Trial.

BACKGROUND Premature labor is an important cause of infant death and long-term disability. This study aimed to explore the safety and effectiveness of combining the tocolytic agents atosiban and ritodrine to extend gestation. MATERIAL AND METHODS The study included 52 patients with late threatened abortion and threatened premature labor between 20°â¸7 and 336⸍7 weeks' gestation who were administrated continuous tocolytic agents for 48 h. Patients were divided into a research group receiving ritodrine combined with atosiban, owing to having no response to ritodrine alone (n=30), and a control group receiving ritodrine alone (n=22). The mean infusion rate and duration of tocolytic administration, gestation extension, pregnancy outcomes, and adverse effects were recorded. Routine blood tests, including C-reactive protein, and cultures for leukorrhea, candida, and mycoplasma were performed before and 1 week after treatment. RESULTS Patients receiving ritodrine with atosiban had a mean gestation extension of 42.53±31.70 days. The extension of gestation of the research group was statistically shorter than that of the control group (P<0.05). The fetal loss rate, newborn birth weight, and Apgar score at 1 min were similar between the 2 groups (all, P>0.05). The research group had a lower incidence of palpitations than the control group (P<0.05). CONCLUSIONS For patients with late threatened abortion or threatened premature labor not controlled with ritodrine alone, ritodrine combined with atosiban extends gestation and improves pregnancy outcomes. For patients with abnormal uterine contractions, routine testing for reproductive tract infection should be performed. When infection is present, anti-infective therapy should be administered.

Oxytocin receptor antagonists as a novel pharmacological agent for reducing smooth muscle tone in the human prostate.

Pharmacotherapies for the treatment of Benign Prostatic Hyperplasia (BPH) are targeted at reducing cellular proliferation (static component) or reducing smooth muscle tone (dynamic component), but response is unpredictable and many patients fail to respond. An impediment to identifying novel pharmacotherapies is the incomplete understanding of paracrine signalling. Oxytocin has been highlighted as a potential paracrine mediator of BPH. To better understand oxytocin signalling, we investigated the effects of exogenous oxytocin on both stromal cell proliferation, and inherent spontaneous prostate contractions using primary models derived from human prostate tissue. We show that the Oxytocin Receptor (OXTR) is widely expressed in the human prostate, and co-localises to contractile cells within the prostate stroma. Exogenous oxytocin did not modulate prostatic fibroblast proliferation, but did significantly (p < 0.05) upregulate the frequency of spontaneous contractions in prostate tissue, indicating a role in generating smooth muscle tone. Application of atosiban, an OXTR antagonist, significantly (p < 0.05) reduced spontaneous contractions. Individual tissue responsiveness to both exogenous oxytocin (R2 = 0.697, p < 0.01) and atosiban (R2 = 0.472, p < 0.05) was greater in tissue collected from older men. Overall, our data suggest that oxytocin is a key regulator of inherent spontaneous prostate contractions, and targeting of the OXTR and associated downstream signalling is an attractive prospect in the development of novel BPH pharmacotherapies.

Usefulness of atosiban for tocolysis during external cephalic version: Systematic review and meta-analysis.

INTRODUCTION: Breech/transverse presentation is responsible for about 30-50 % of cesarean sections in the world. Cesarean section carries a five-fold greater morbidity than vaginal delivery, deeply impacting on women's health. External Cephalic Version (ECV) is an external manipulation used to convert a non-cephalic to a cephalic presentation. The use of tocolysis might facilitate this procedure; however, it is still controversial which drug should be considered as first choice. OBJECTIVE: To assess the effectiveness of tocolysis with atosiban, a competitive oxytocin receptor antagonist, in order to increase the rate of successful ECV. STUDY DESIGN: Nine databases (including MEDLINE, CINAHL, LILACS, EMBASE, Scopus, ClinicalTrials.gov, Scielo, PROSPERO, Cochrane at CENTRAL) were searched from the inception to August 2020 using a combination of MeSH terms and keywords regarding "atosiban" and "external cephalic version". We included trials of women with a singleton pregnancy who reached at least 36 weeks of gestation and were scheduled to ECV and tocolysis with atosiban (intervention group) compared to beta-agonists or other drugs (control group). The primary outcome was the incidence of successful ECV. Summary measures were reported as relative risk (RR) with 95 % confidence interval (CI). DATA COLLECTION AND ANALYSIS: Four studies (1534 women) were eligible for analysis. ECV success rate was significantly lower in women randomized to atosiban (36.7 % vs 45.3 %; RR 0.78 [95 % CI 0.6 to 0.98]). Cesarean section and vaginal delivery rates did not differ between intervention and control group ((59.8 % vs 52.6 %; RR 1.17 [0.98-1.38] and (38.6 % vs 45.0 %; RR 0.83 [95 % CI 0.69-1.01] respectively). Cephalic (36.9 % vs 44.6 %; RR 0.81 [95 % CI 0.65 to 1.01], or breech/transverse presentation at labor (63.4 % vs 55.1 %; RR 1.18 [95 % CI 0.99-1.40]), APGAR score less than 7 at 5 min (1.6 % vs 2.0 %; RR 1.14 [95 % CI 0.27-4.73], NICU admissions (44.2 % vs 48.1 %; RR 0.92 [95 % CI 0.58-1.46] and Umbilical cord pH were similar in both groups. Drug-related side effects were lower in women randomized to atosiban, compared with control group (16.0 % vs 42.9 %; RR 0.38 [95 % CI 0.31 to 0.47]. CONCLUSION: The use of atosiban for tocolysis does not improve the rate of successful ECVs when compared to beta-agonists. However, atosiban was associated with a significantly lower incidence of side effects and comparable cesarean section rates.