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Gan HW, Leeson C, Aitkenhead H, Dattani M. Inaccuracies in plasma oxytocin extraction and enzyme immunoassay techniques. COMPREHENSIVE PSYCHONEUROENDOCRINOLOGY 2023; 15:100188. [PMID: 37360277 PMCID: PMC10285453 DOI: 10.1016/j.cpnec.2023.100188] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 06/01/2023] [Accepted: 06/04/2023] [Indexed: 06/28/2023] Open
Abstract
Numerous studies have reported extensive associations between plasma oxytocin (OXT) concentrations and various human physiological and neurobehavioral processes. Measurement of OXT is fraught with difficulty due to its low molecular weight and plasma concentrations, with no consensus as to the optimal conditions for pre-analytical sample extraction, standards for immunoassay validation or the ideal protease inhibitors to prevent OXT degradation. Previous attempts at determining the efficacy of various purification techniques such as solid phase extraction (SPE) or ultrafiltration have only utilized human plasma samples, making it difficult to dissect out whether the effect of interference comes from the extraction process itself or cross-reactivity with other proteins. By testing these on pure OXT solutions, we demonstrate poor recovery efficacy and reliability of reversed phase SPE (maximum 58.1%) and ultrafiltration (<1%) techniques, and the potential for the former to introduce interference into enzyme immunoassay (EIA) measurements. The clonality of antibodies used in EIA kits also potentially contributes to the differences in the readings obtained, and we validate an EIA kit which did not require pre-analytical sample extraction with low cross-reactivity and high reliability (intraclass correlation coefficient 0.980 (95% CI 0.896-0.999). Biochemical techniques used for measuring plasma OXT concentrations must therefore be internally validated prior to translation into clinical studies.
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Affiliation(s)
- Hoong-Wei Gan
- Genetics & Genomic Medicine Research and Training Department, UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, United Kingdom
- Great Ormond Street Hospital for Children NHS Foundation Trust, Great Ormond Street, London, WC1N 3JH, United Kingdom
| | - Clare Leeson
- Great Ormond Street Hospital for Children NHS Foundation Trust, Great Ormond Street, London, WC1N 3JH, United Kingdom
| | - Helen Aitkenhead
- Great Ormond Street Hospital for Children NHS Foundation Trust, Great Ormond Street, London, WC1N 3JH, United Kingdom
| | - Mehul Dattani
- Genetics & Genomic Medicine Research and Training Department, UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, United Kingdom
- Great Ormond Street Hospital for Children NHS Foundation Trust, Great Ormond Street, London, WC1N 3JH, United Kingdom
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2
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Buckley S, Uvnäs-Moberg K, Pajalic Z, Luegmair K, Ekström-Bergström A, Dencker A, Massarotti C, Kotlowska A, Callaway L, Morano S, Olza I, Magistretti CM. Maternal and newborn plasma oxytocin levels in response to maternal synthetic oxytocin administration during labour, birth and postpartum - a systematic review with implications for the function of the oxytocinergic system. BMC Pregnancy Childbirth 2023; 23:137. [PMID: 36864410 PMCID: PMC9979579 DOI: 10.1186/s12884-022-05221-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 11/15/2022] [Indexed: 03/04/2023] Open
Abstract
BACKGROUND The reproductive hormone oxytocin facilitates labour, birth and postpartum adaptations for women and newborns. Synthetic oxytocin is commonly given to induce or augment labour and to decrease postpartum bleeding. AIM To systematically review studies measuring plasma oxytocin levels in women and newborns following maternal administration of synthetic oxytocin during labour, birth and/or postpartum and to consider possible impacts on endogenous oxytocin and related systems. METHODS Systematic searches of PubMed, CINAHL, PsycInfo and Scopus databases followed PRISMA guidelines, including all peer-reviewed studies in languages understood by the authors. Thirty-five publications met inclusion criteria, including 1373 women and 148 newborns. Studies varied substantially in design and methodology, so classical meta-analysis was not possible. Therefore, results were categorized, analysed and summarised in text and tables. RESULTS Infusions of synthetic oxytocin increased maternal plasma oxytocin levels dose-dependently; doubling the infusion rate approximately doubled oxytocin levels. Infusions below 10 milliunits per minute (mU/min) did not raise maternal oxytocin above the range observed in physiological labour. At high intrapartum infusion rates (up to 32 mU/min) maternal plasma oxytocin reached 2-3 times physiological levels. Postpartum synthetic oxytocin regimens used comparatively higher doses with shorter duration compared to labour, giving greater but transient maternal oxytocin elevations. Total postpartum dose was comparable to total intrapartum dose following vaginal birth, but post-caesarean dosages were higher. Newborn oxytocin levels were higher in the umbilical artery vs. umbilical vein, and both were higher than maternal plasma levels, implying substantial fetal oxytocin production in labour. Newborn oxytocin levels were not further elevated following maternal intrapartum synthetic oxytocin, suggesting that synthetic oxytocin at clinical doses does not cross from mother to fetus. CONCLUSIONS Synthetic oxytocin infusion during labour increased maternal plasma oxytocin levels 2-3-fold at the highest doses and was not associated with neonatal plasma oxytocin elevations. Therefore, direct effects from synthetic oxytocin transfer to maternal brain or fetus are unlikely. However, infusions of synthetic oxytocin in labour change uterine contraction patterns. This may influence uterine blood flow and maternal autonomic nervous system activity, potentially harming the fetus and increasing maternal pain and stress.
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Affiliation(s)
- Sarah Buckley
- grid.1003.20000 0000 9320 7537Faculty of Medicine, The University of Queensland, Brisbane, Australia
| | | | - Zada Pajalic
- grid.463529.f0000 0004 0610 6148Faculty for Health Sciences, VID Specialized University, Oslo, Norway
| | - Karolina Luegmair
- grid.9018.00000 0001 0679 2801Institute for Health Care and Nursing Studies, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Anette Ekström-Bergström
- grid.412716.70000 0000 8970 3706Department of Health Sciences, University West, Trollhättan, Sweden
| | - Anna Dencker
- grid.8761.80000 0000 9919 9582Institute of Health and Care Sciences, The Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden
| | - Claudia Massarotti
- grid.5606.50000 0001 2151 3065Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy
| | - Alicja Kotlowska
- grid.11451.300000 0001 0531 3426Department of Clinical and Experimental Endocrinology, Faculty of Health Sciences, Medical University of Gdańsk, Gdańsk, Poland
| | - Leonie Callaway
- grid.1003.20000 0000 9320 7537Faculty of Medicine, The University of Queensland, Brisbane, Australia
| | - Sandra Morano
- grid.5606.50000 0001 2151 3065Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy
| | - Ibone Olza
- European Institute of Perinatal Mental Health, Madrid, Spain
| | - Claudia Meier Magistretti
- grid.425064.10000 0001 2191 8943Institute for Health Policies, Prevention and Health Promotion, Lucerne University of Applied Sciences and Arts, Luzern, Switzerland
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Nathan NO, Hedegaard M, Karlsson G, Knudsen LE, Mathiesen L. Intrapartum transfer of oxytocin across the human placenta: An ex vivo perfusion experiment. Placenta 2021; 112:105-110. [PMID: 34329968 DOI: 10.1016/j.placenta.2021.07.289] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 05/24/2021] [Accepted: 07/19/2021] [Indexed: 11/26/2022]
Abstract
INTRODUCTION Investigation of the maternal to fetal transfer of oxytocin across the dually perfused term human placenta. METHODS Human placentae obtained from term singleton pregnancies were utilized in a dual recirculating model of ex vivo placental perfusion. Six placentae from women delivering by elective cesarean at term were perfused, one blank and five with the test substance synthetic oxytocin (0.8 ng/mL) (OX) added to the maternal perfusate for 180 min. Antipyrine was used as positive control to validate overlap of the maternal and fetal circuits. The concentration of OX was determined by radioimmunoassay. RESULTS A fall in maternal concentration of OX was seen throughout the experiment. At 90 min of perfusion a state of equilibrium was reached between maternal and fetal concentrations; however after 180 min the fetal concentration of OX was higher than that of the maternal. 31 % of the test substance was accounted for at the end of the experiment - suggesting OX protein binding and a high degree of oxytocinase activity. DISCUSSION The ex vivo perfusion experiments revealed low transfer of OX to the fetal circuit below physiologically relevant concentrations.
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Affiliation(s)
- Nina Olsén Nathan
- The Research Unit Women's and Children's Health, The Juliane Marie Centre for Women, Children and Reproduction, Copenhagen University Hospital, Rigshospitalet, Tagensvej 22, 2200, Copenhagen, Denmark; Department of Obstetrics, Copenhagen University Hospital Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark
| | - Morten Hedegaard
- Department of Obstetrics, Copenhagen University Hospital Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark
| | - Gösta Karlsson
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden; Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
| | - Lisbeth E Knudsen
- Section of Environmental Health, Department of Public Health, University of Copenhagen, Øster Farimagsgade 5, Building 9, 1014, Copenhagen, Denmark
| | - Line Mathiesen
- Section of Environmental Health, Department of Public Health, University of Copenhagen, Øster Farimagsgade 5, Building 9, 1014, Copenhagen, Denmark.
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Arrowsmith S, Wray S. Oxytocin: its mechanism of action and receptor signalling in the myometrium. J Neuroendocrinol 2014; 26:356-69. [PMID: 24888645 DOI: 10.1111/jne.12154] [Citation(s) in RCA: 165] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 03/14/2014] [Accepted: 03/28/2014] [Indexed: 12/17/2022]
Abstract
Oxytocin is a nonapeptide hormone that has a central role in the regulation of parturition and lactation. In this review, we address oxytocin receptor (OTR) signalling and its role in the myometrium during pregnancy and in labour. The OTR belongs to the rhodopsin-type (Class 1) of the G-protein coupled receptor superfamily and is regulated by changes in receptor expression, receptor desensitisation and local changes in oxytocin concentration. Receptor activation triggers a number of signalling events to stimulate contraction, primarily by elevating intracellular calcium (Ca(2+) ). This includes inositol-tris-phosphate-mediated store calcium release, store-operated Ca(2+) entry and voltage-operated Ca(2+) entry. We discuss each mechanism in turn and also discuss Ca(2+) -independent mechanisms such as Ca(2+) sensitisation. Because oxytocin induces contraction in the myometrium, both the activation and the inhibition of its receptor have long been targets in the management of dysfunctional and preterm labours, respectively. We discuss current and novel OTR agonists and antagonists and their use and potential benefit in obstetric practice. In this regard, we highlight three clinical scenarios: dysfunctional labour, postpartum haemorrhage and preterm birth.
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Affiliation(s)
- S Arrowsmith
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
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Mazzuca M, Minlebaev M, Shakirzyanova A, Tyzio R, Taccola G, Janackova S, Gataullina S, Ben-Ari Y, Giniatullin R, Khazipov R. Newborn Analgesia Mediated by Oxytocin during Delivery. Front Cell Neurosci 2011; 5:3. [PMID: 21519396 PMCID: PMC3080614 DOI: 10.3389/fncel.2011.00003] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Accepted: 03/31/2011] [Indexed: 12/02/2022] Open
Abstract
The mechanisms controlling pain in newborns during delivery are poorly understood. We explored the hypothesis that oxytocin, an essential hormone for labor and a powerful neuromodulator, exerts analgesic actions on newborns during delivery. Using a thermal tail-flick assay, we report that pain sensitivity is two-fold lower in rat pups immediately after birth than 2 days later. Oxytocin receptor antagonists strongly enhanced pain sensitivity in newborn, but not in 2-day-old rats, whereas oxytocin reduced pain at both ages suggesting an endogenous analgesia by oxytocin during delivery. Similar analgesic effects of oxytocin, measured as attenuation of pain-vocalization induced by electrical whisker pad stimulation, were also observed in decerebrated newborns. Oxytocin reduced GABA-evoked calcium responses and depolarizing GABA driving force in isolated neonatal trigeminal neurons suggesting that oxytocin effects are mediated by alterations of intracellular chloride. Unlike GABA signaling, oxytocin did not affect responses mediated by P2X3 and TRPV1 receptors. In keeping with a GABAergic mechanism, reduction of intracellular chloride by the diuretic NKCC1 chloride co-transporter antagonist bumetanide mimicked the analgesic actions of oxytocin and its effects on GABA responses in nociceptive neurons. Therefore, endogenous oxytocin exerts an analgesic action in newborn pups that involves a reduction of the depolarizing action of GABA on nociceptive neurons. Therefore, the same hormone that triggers delivery also acts as a natural pain killer revealing a novel facet of the protective actions of oxytocin in the fetus at birth.
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Affiliation(s)
- Michel Mazzuca
- INMED/INSERM U901, Université de la Méditerranée Marseille, France
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Endoh H, Fujioka T, Endo H, Inazuka Y, Furukawa S, Nakamura S. Stimulation of Fetal Hypothalamus Induces Uterine Contractions in Pregnant Rats at Term1. Biol Reprod 2008; 79:633-7. [DOI: 10.1095/biolreprod.108.069120] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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Tyzio R, Cossart R, Khalilov I, Represa A, Ben-Ari Y, Khazipov R. Response to Comment on "Maternal Oxytocin Triggers a Transient Inhibitory Switch in GABA Signaling in the Fetal Brain During Delivery". Science 2007. [DOI: 10.1126/science.1141555] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Wilson L, Parsons MT, Ouano L, Flouret G. A new tocolytic agent: development of an oxytocin antagonist for inhibiting uterine contractions. Am J Obstet Gynecol 1990; 163:195-202. [PMID: 2375344 DOI: 10.1016/s0002-9378(11)90698-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A potent oxytocin antagonist has been developed and tested on both the rat and human uterus. In the rat the oxytocin antagonist: (1) inhibited in vitro and in vivo uterine contractions in the nonpregnant animal in response to exogenous oxytocin, (2) inhibited milk letdown, and (3) disrupted the progress of labor. In addition, the oxytocin antagonist inhibited the in vitro contractile response to exogenous oxytocin of human myometrial tissue obtained by cesarean section at term. The results of these studies suggest that the oxytocin antagonist can be used to study the role of oxytocin in labor and has the potential of inhibiting preterm labor in humans.
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Affiliation(s)
- L Wilson
- Department of Obstetrics and Gynecology, University of Illinois, College of Medicine, Chicago 60612
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Marchini G, Lagercrantz H, Winberg J, Uvnäs-Moberg K. Fetal and maternal plasma levels of gastrin, somatostatin and oxytocin after vaginal delivery and elective cesarean section. Early Hum Dev 1988; 18:73-9. [PMID: 2906866 DOI: 10.1016/0378-3782(88)90044-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
We measured the cord levels of gastrin, somatostatin and oxytocin with radioimmunoassay in plasma collected from the umbilical artery after vaginal delivery and after elective cesarean section. Maternal venous samples after the two labour modalities were also assayed for the same hormones. Fetal gastrin, somatostatin and oxytocin levels were significantly higher after vaginal delivery than after elective cesarean section. Independently of labour type, the fetal gastrin and somatostatin levels were always higher than the maternal levels. We suggest that the observed high levels of gastrin, somatostatin and oxytocin could be due to a stress-related stimulation of the oxytocin- as well as of the gastric gastrin- and somatostatin-producing cells, occurring particularly during vaginal delivery. The significant inverse correlation found between fetal pH and the recorded hormone levels is consistent with this hypothesis.
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Affiliation(s)
- G Marchini
- Department of Paediatrics, Karolinska Hospital, Stockholm, Sweden
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Padayachi T, Norman RJ, Dhavaraj K, Kemp M, Joubert SM. Serial oxytocin levels in amniotic fluid and maternal plasma during normal and induced labour. BRITISH JOURNAL OF OBSTETRICS AND GYNAECOLOGY 1988; 95:888-93. [PMID: 3191062 DOI: 10.1111/j.1471-0528.1988.tb06575.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Oxytocin was measured by a specific and sensitive radioimmunoassay in plasma and amniotic fluid after extraction with Sep-Pak cartridges in patients undergoing elective caesarean sections, normal labour and labour induced with oxytocin infusion or prostaglandins. In maternal plasma, levels of oxytocin correlated with the period of gestation; concentrations at term were significantly higher than in the first two trimesters. Maternal plasma levels of oxytocin before the onset of contractions were not significantly different from those at the onset of spontaneous labour or at full cervical dilatation. Levels of oxytocin in patients induced with oxytocin were not statistically different from levels observed in spontaneous labour. Amniotic fluid oxytocin levels were not significantly different between the groups either at the onset of labour or immediately before delivery. Umbilical arterio-venous differences in oxytocin were present in all groups except the prostaglandin-induced group. Increased prostaglandins associated with the onset of normal labour are probably not a consequence of changes in oxytocin concentrations.
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Affiliation(s)
- T Padayachi
- University of Natal Medical School, Natal, Republic of South Africa
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