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Lammers SM, Peczkowski KK, Patel N, Abdelwahab M, Summerfield TL, Costantine MM, Janssen PML, Kniss DA, Frey HA. Maternal Body Mass Index, Myometrium Contractility and Uterotonic Receptor Expression in Pregnancy. Reprod Sci 2024:10.1007/s43032-024-01661-1. [PMID: 39060750 DOI: 10.1007/s43032-024-01661-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Accepted: 07/16/2024] [Indexed: 07/28/2024]
Abstract
Pregnant individuals with obesity (body mass index, BMI ≥ 30 kg/m2) are more likely to experience prolonged labor and have double the risk of cesarean compared with individuals with normal weight (BMI < 25 kg/m2). The aim of this study was to evaluate whether obesity in pregnancy is associated with reduced spontaneous and oxytocin-stimulated myometrial contractile activity using ex vivo preparations. We also assessed the relationship between maternal BMI and the expression of oxytocin (OXTR) and prostaglandin (FP) receptors in the myometrial tissue. We enrolled 73 individuals with a singleton gestation undergoing scheduled cesarean delivery at term in a prospective cohort study. This included 49 individuals with a pre-pregnancy BMI ≥ 30 kg/m2 and 24 with BMI < 25.0 kg/m2. After delivery, a small strip of myometrium was excised from the upper edge of the hysterotomy. Baseline spontaneous and oxytocin stimulated myometrial contractile activity was measured using ex vivo preparations. Additionally, expression of oxytocin and prostaglandin receptors from myometrial samples were compared using qRT-PCR and western blot techniques. Spontaneous and oxytocin-stimulated contraction frequency, duration, and force were not significantly different in myometrial samples from the obese and normal-weight individuals. Myometrial OXTR gene and protein expression was also similar in the two groups. While FP gene expression was lower in the myometrial samples from the obese group, protein expression did not differ. These data help to address an important knowledge gap related to the biological mechanisms underlying the association between maternal obesity and dysfunctional labor.
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Affiliation(s)
- Sydney M Lammers
- Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, The Ohio State University College of Medicine, 395 W. 12Th Ave, 5Th Floor, Columbus, OH, USA
| | - Kyra K Peczkowski
- Department of Physiology and Cell Biology, The Ohio State University, College of Medicine, Columbus, OH, USA
| | - Niharika Patel
- Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, The Ohio State University College of Medicine, 395 W. 12Th Ave, 5Th Floor, Columbus, OH, USA
| | - Mahmoud Abdelwahab
- Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, The Ohio State University College of Medicine, 395 W. 12Th Ave, 5Th Floor, Columbus, OH, USA
| | - Taryn L Summerfield
- Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, The Ohio State University College of Medicine, 395 W. 12Th Ave, 5Th Floor, Columbus, OH, USA
| | - Maged M Costantine
- Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, The Ohio State University College of Medicine, 395 W. 12Th Ave, 5Th Floor, Columbus, OH, USA
| | - Paul M L Janssen
- Department of Physiology and Cell Biology, The Ohio State University, College of Medicine, Columbus, OH, USA
| | - Douglas A Kniss
- Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, The Ohio State University College of Medicine, 395 W. 12Th Ave, 5Th Floor, Columbus, OH, USA
- Laboratory of Perinatal Research, The Ohio State University, Wexner Medical Center, Columbus, OH, USA
| | - Heather A Frey
- Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, The Ohio State University College of Medicine, 395 W. 12Th Ave, 5Th Floor, Columbus, OH, USA.
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Tyagi A, Nigam C, Malhotra RK, Bodh P, Deep S, Singla A. The minimum effective dose (ED 90) of prophylactic oxytocin infusion during cesarean delivery in patients with and without obesity: an up-down sequential allocation dose-response study. Int J Obstet Anesth 2024; 57:103962. [PMID: 38103940 DOI: 10.1016/j.ijoa.2023.103962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Revised: 11/14/2023] [Accepted: 11/27/2023] [Indexed: 12/19/2023]
Abstract
BACKGROUND Obesity is associated with greater oxytocin requirement during labor induction or augmentation. There are scant data exploring the intra-operative requirement during cesarean delivery in patients with obesity, and none comparing it with those without obesity. We evaluated the minimum effective dose (ED90) of an oxytocin infusion to achieve adequate uterine tone during cesarean delivery in patients with and without obesity. METHODS Patients (body mass index ≥30 kg/m2 represented patients with obesity) undergoing cesarean delivery using subarachnoid block were included. This prospective dual-arm dose-finding study used a 9:1 biased sequential allocation design. Oxytocin infusion was initiated at 13 IU/h at cord clamping in the first patient of each group. Uterine tone was graded as satisfactory or unsatisfactory by the obstetrician four minutes after initiation of the infusion. The dose of oxytocin infusion for subsequent patients was determined according to the response of the previous patient in the group. Oxytocin-associated side effects were evaluated. Dose-response data for the groups was evaluated using log-logistic function and ED90 estimates derived from fitted equations using the delta method. RESULTS The ED90 of oxytocin was significantly higher for patients with obesity (n = 40) compared with those without obesity (n = 40) [25.7 IU/h, 95% CI 18.6 to 32.9) vs. 16.6 IU/h, 95% CI 14.9 to 18.3)]; relative ratio 1.55 [95% CI 1.09 to 2.01] (P = 0.019). CONCLUSIONS Patients with obesity require a higher intra-operative oxytocin infusion dose rate to achieve a satisfactorily contracted uterus after fetal delivery when compared with patients without obesity.
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Affiliation(s)
- A Tyagi
- Department of Anaesthesiology and Critical Care, University College of Medical Sciences and GTB Hospital, Delhi, India.
| | - C Nigam
- Department of Anaesthesiology and Critical Care, University College of Medical Sciences and GTB Hospital, Delhi, India
| | - R K Malhotra
- Delhi Cancer Registry, Dr BR Ambedkar Institute-Rotary Cancer Hospital, All India Institute of Medical Sciences, New Delhi, India
| | - P Bodh
- Department of Anaesthesiology and Critical Care, University College of Medical Sciences and GTB Hospital, Delhi, India
| | - S Deep
- Department of Anaesthesiology and Critical Care, University College of Medical Sciences and GTB Hospital, Delhi, India
| | - A Singla
- Department of Obstetrics and Gynaecology, University College of Medical Sciences and GTB Hospital, Delhi, India
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Kissler K, Hurt KJ. The Pathophysiology of Labor Dystocia: Theme with Variations. Reprod Sci 2023; 30:729-742. [PMID: 35817950 PMCID: PMC10388369 DOI: 10.1007/s43032-022-01018-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 06/16/2022] [Indexed: 10/17/2022]
Abstract
Abnormally prolonged labor, or labor dystocia, is a common complication of parturition. It is the indication for about half of unplanned cesarean deliveries in low-risk nulliparous women. Reducing the rate of unplanned cesarean birth in the USA has been a public health priority over the last two decades with limited success. Labor dystocia is a complex disorder due to multiple causes with a common clinical outcome of slow cervical dilation and fetal descent. A better understanding of the pathophysiologic mechanisms of labor dystocia could lead to new clinical opportunities to increase the rate of normal vaginal delivery, reduce cesarean birth rates, and improve maternal and neonatal health. We conducted a literature review of the causes and pathophysiologic mechanisms of labor dystocia. We summarize known mechanisms supported by clinical and experimental data and newer hypotheses with less supporting evidence. We review recent data on uterine preparation for labor, uterine contractility, cervical preparation for labor, maternal obesity, cephalopelvic disproportion, fetal malposition, intrauterine infection, and maternal stress. We also describe current clinical approaches to preventing and managing labor dystocia. The variation in pathophysiologic causes of labor dystocia probably limits the utility of current general treatment options. However, treatments targeting specific underlying etiologies could be more effective. We found that the pathophysiologic basis of labor dystocia is under-researched, offering wide opportunities for translational investigation of individualized labor management, particularly regarding uterine metabolism and fetal position. More precise diagnostic tools and individualized therapies for labor dystocia might lead to better outcomes. We conclude that additional knowledge of parturition physiology coupled with rigorous clinical evaluation of novel biologically directed treatments could improve obstetric quality of care.
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Affiliation(s)
- Katherine Kissler
- College of Nursing, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - K Joseph Hurt
- Division of Reproductive Sciences, Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, 12700 East 19th Avenue, Aurora, CO, 80045, USA.
- Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, 12700 East 19th Avenue, Mailstop 8613, Aurora, CO, 80045, USA.
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Grimm MJ. Forces Involved with Labor and Delivery-A Biomechanical Perspective. Ann Biomed Eng 2021; 49:1819-1835. [PMID: 33432512 DOI: 10.1007/s10439-020-02718-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Accepted: 12/25/2020] [Indexed: 12/20/2022]
Abstract
Childbirth is a primarily biomechanical process of physiology, and one that engineers have recently begun to address in a broader fashion. Computational models are being developed to address the biomechanical effects of parturition on both maternal and fetal tissues. Experimental research is being conducted to understand how maternal tissues adapt to intrauterine forces near the onset of labor. All of this research requires an understanding of the forces that are developed through maternal efforts-both uterine contractions and semi-voluntary pushing-and that can be applied by the clinician to assist with the delivery. This work reviews the current state of knowledge regarding forces of labor and delivery, with a focus on macro-level biomechanics.
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Affiliation(s)
- Michele J Grimm
- Departments of Mechanical Engineering and Biomedical Engineering, Michigan State University, 428 S. Shaw Lane, East Lansing, MI, 48824, USA.
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5
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A Swedish register-based study exploring primary postpartum hemorrhage in 405 936 full term vaginal births between 2005 and 2015. Eur J Obstet Gynecol Reprod Biol 2021; 258:184-188. [PMID: 33450708 DOI: 10.1016/j.ejogrb.2020.12.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Revised: 11/25/2020] [Accepted: 12/06/2020] [Indexed: 11/23/2022]
Abstract
OBJECTIVE To explore diagnoses of postpartum haemorrhage following vaginal birth, in relation to socio-demographic and obstetrical data from women who gave birth at term, in Sweden, during the years 2005-2015. STUDY DESIGN A register-based cohort study was carried out, describing and comparing socio-demographic variables, obstetric variables and infant variables in 52 367 cases of diagnosed postpartum haemorrhage compared to 353 569 controls without a postpartum haemorrhage diagnosis. Postpartum hemorrhage was identified in The Swedish Medical Birth Register by ICD-10 code O72. Variables for maternal characteristics were dichotomized and used to calculate odds ratios to find possible explanatory variables for postpartum haemorrhage. RESULTS Between 2005 and 2015 there was no statistically significant decrease in diagnoses of postpartum haemorrhage after vaginal birth at term. Primiparity was associated with the highest risk and women birthing their fifth or subsequent child were associated with the lowest risk of postpartum hemorrhage. Increased maternal age (> 35 years) and/or obesity (BMI > 30) were associated with higher odds of postpartum haemorrhage. The risk of postpartum hemorrhage was 55 % higher when vaginal birth followed induction as compared to vaginal birth after spontaneous onset. Some of the factors known to be associated with postpartum haemorrhage were poorly documented in The Swedish Medical Birth Register. CONCLUSIONS Birthing women in a Swedish contemporary setting are, despite efforts to improve care, still at risk of birth being complicated by postpartum haemorrhage. Primiparity, increasing maternal age and/or obesity are found to provoke an increased risk and the reasons for these findings need to be further investigated. However, grand multi-parity did not increase the risk for postpartum hemorrhage. Codes for diagnoses require correct documentation in the birth records: only when local statistics are sound and correctly reported can intrapartum care be improved, and the incidence of postpartum haemorrhage reduced.
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Ryan GA, Nicholson SM, Crankshaw DJ, Morrison JJ. Spontaneous Human Myometrial Contractility in the Third Trimester of Pregnancy in Relation to Past Mode of Delivery. Am J Perinatol 2021; 38:126-130. [PMID: 31430820 DOI: 10.1055/s-0039-1694980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
OBJECTIVE It is well established that women with a previous vaginal delivery have higher success rates in relation to vaginal birth after cesarean than those without. The aim of this study was to examine the effect of past mode of delivery on contractile parameters of human myometrium in vitro. STUDY DESIGN Myometrial strips were excised from 64 women at cesarean delivery (CD) and recordings of spontaneous contractile activity analyzed and compared across three clinical groups: (1) women with no previous delivery (Group 1); (2) women with CD only (Group 2); and (3) women with a history of vaginal delivery and CD (Group 3). RESULTS Myometrial samples from women in Group 3, women who had a previous vaginal delivery, had a significantly greater maximum amplitude of contractions (p < 0.05), a greater force (mean contractile force) of contractions (p < 0.01), and a faster rate of rise (p < 0.01) and relaxation of contractions (p < 0.05) than those in Groups 1 and 2. CONCLUSION Many of the functional parameters of human uterine contractions are altered, or enhanced, in the women who have had a previous vaginal delivery, when compared with those without. This may partly explain the clinical differences observed in labor.
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Affiliation(s)
- Gillian A Ryan
- Department of Obstetrics and Gynecology, Galway University Hospital, National University of Ireland Galway, Galway, Ireland.,Department of Obstetrics and Gynecology, Lambe Institute for Translational Research, National University of Ireland Galway, Galway, Ireland
| | - Sarah M Nicholson
- Department of Obstetrics and Gynecology, Galway University Hospital, National University of Ireland Galway, Galway, Ireland
| | - Denis J Crankshaw
- Department of Obstetrics and Gynecology, Galway University Hospital, National University of Ireland Galway, Galway, Ireland.,Department of Obstetrics and Gynecology, Lambe Institute for Translational Research, National University of Ireland Galway, Galway, Ireland
| | - John J Morrison
- Department of Obstetrics and Gynecology, Galway University Hospital, National University of Ireland Galway, Galway, Ireland.,Department of Obstetrics and Gynecology, Lambe Institute for Translational Research, National University of Ireland Galway, Galway, Ireland
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The effect of morbid obesity or advanced maternal age on oxytocin-induced myometrial contractions: an in vitro study. Can J Anaesth 2020; 67:836-846. [PMID: 32189217 DOI: 10.1007/s12630-020-01615-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 01/29/2020] [Accepted: 02/01/2020] [Indexed: 12/13/2022] Open
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Prendergast C. Maternal phenotype: how do age, obesity and diabetes affect myometrial function? CURRENT OPINION IN PHYSIOLOGY 2020. [DOI: 10.1016/j.cophys.2019.10.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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9
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Vyas V, Guerra DD, Bok R, Powell T, Jansson T, Hurt KJ. Adiponectin links maternal metabolism to uterine contractility. FASEB J 2019; 33:14588-14601. [PMID: 31665924 PMCID: PMC6894045 DOI: 10.1096/fj.201901646r] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2019] [Accepted: 09/23/2019] [Indexed: 12/31/2022]
Abstract
Adiponectin is secreted by adipose tissue and promotes insulin sensitivity. Low circulating adiponectin is associated with increased risk for preterm labor, but the influence of adiponectin on uterine myometrial physiology is unknown. We hypothesized that adiponectin receptors (AdipoRs) decrease myometrial contractility via AMPK to promote uterine quiescence in pregnancy. Using quantitative RT-PCR, we found that nonpregnant or pregnant human and mouse myometrium express AdipoR1 and AdipoR2 mRNAs. We confirmed AdipoR2 protein expression in human and mouse myometrium, with increased abundance in late mouse pregnancy. Both recombinant adiponectin and a pharmacologic AdipoR agonist, AdipoRon, potently inhibited uterine myometrial strip contractions in physiologic organ bath. The relaxation was independent of contractile stimulus (oxytocin, KCl, U46619). AdipoR agonists increased AMPK phosphorylation in pregnant mouse myometrium, and the direct AMPK activator A769662 also relaxed myometrial strips. However, the AMPK inhibitor dorsomorphin (compound C) blocked AMPK phosphorylation but did not abolish relaxation with either AdipoRon or A769662. In summary, adiponectin inhibits myometrial contractility consistent with the possibility that it is a previously unrecognized link between maternal metabolism and pregnancy maintenance. We also identify a separate role for AMPK regulating myometrial contractions that may influence labor onset.-Vyas, V., Guerra, D. D., Bok, R., Powell, T., Jansson, T., Hurt, K. J. Adiponectin links maternal metabolism to uterine contractility.
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Affiliation(s)
- Vibhuti Vyas
- Division of Reproductive Sciences, Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Damian D. Guerra
- Division of Reproductive Sciences, Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Rachael Bok
- Division of Reproductive Sciences, Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Theresa Powell
- Division of Reproductive Sciences, Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
- Division of Neonatology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA; and
| | - Thomas Jansson
- Division of Reproductive Sciences, Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - K. Joseph Hurt
- Division of Reproductive Sciences, Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
- Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
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Maternal parity and functional contractility of human myometrium in vitro in the third trimester of pregnancy. J Perinatol 2019; 39:439-444. [PMID: 30655596 DOI: 10.1038/s41372-019-0312-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Revised: 12/06/2018] [Accepted: 12/23/2018] [Indexed: 01/28/2023]
Abstract
OBJECTIVE It is well established that the duration of the first and second stages of labor are shorter in parous women than in their nulliparous counterparts, a phenomenon not well understood. The aim was to examine the effect of maternal parity on contractile parameters of human myometrium. DESIGN Myometrial strips were excised from n = 74 women at cesarean delivery and recordings of contractile activity analyzed and compared across three clinical groups: 1. No previous delivery (P0); 2. One previous delivery (P1); 3. Greater than one previous delivery (P>1). RESULTS There was a trend towards greater mean contractile force in the P>1 group than the P1 and P0 groups (P = 0.412). Frequency of contractions was less in the P1 group than in the P0 and P>1 groups(P = 0.027). No differences were observed in relation to all other parameters. CONCLUSION Excluding frequency, no intrinsic differences were observed in the functional parameters of human uterine contractions in relation to parity.
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11
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McDonald S, Satterfield NA, May LE, Newton ER, Livingston J, Fang X. Influence of maternal exercise on fetal heart response during labor and delivery. Health Sci Rep 2018; 1:e81. [PMID: 30623037 PMCID: PMC6266368 DOI: 10.1002/hsr2.81] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 06/26/2018] [Accepted: 07/09/2018] [Indexed: 11/29/2022] Open
Abstract
OBJECTIVES The purpose of this study was to determine if prenatal exercise alters the maternal and fetal heart responses during labor and delivery. We hypothesized that fetuses of exercising mothers would exhibit a lower baseline heart rate (HR), increased HR variability (HRV), and no differences in fetal heart accelerations and decelerations. DESIGN This study employed a cross-sectional design. METHODS The Modifiable Physical Activity Questionnaire was used for group classification. Exercising women were those participating in 30 minutes of moderate-to-vigorous exercise at least 3×/week throughout the entire pregnancy. Women achieving a lower dose of exercise were classified as non-exercisers. Cardiotocography recordings during the first hour of labor and delivery assessed fetal baseline HR, HRV, accelerations, decelerations, and contractions. ANCOVA analyses were performed to assess group differences in these outcomes and were adjusted for maternal body mass index. RESULTS Thirty-one women were included in the analyses. No group mean differences were found for maternal and fetal characteristics, except for maternal age (EX: mean (SD) 28.5 (±4.6y) vs NON-EX: 24.1 (±1.2y)). After controlling for body mass index, no statistical differences in maternal HR response (β = 3.9, SE = 5.0, 95%CI -6.4-14.2) or fetal HR response (β = 3.9, SE = 2.5, 95%CI -1.2-9.11), accelerations and decelerations (β= -0.03, SE = 0.4, 95%CI -0.9-0.8; β= -0.10, SE = 0.4, 95%CI -0.8-0.9, respectively), or HRV (β = 0.6, SE = 1.7, 95%CI -2.8-4.0) were observed. CONCLUSIONS Based on the findings of this study, we found no evidence that maternal exercise during pregnancy was associated with maternal or fetal HR response during labor and delivery. These data suggest maternal exercise may not elicit positive or negative effects on maternal and fetal cardiovascular responses to the physiological stress of labor and delivery.
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Affiliation(s)
- Samantha McDonald
- School of Dental MedicineEast Carolina University (ECU)GreenvilleNCUSA
| | | | - Linda E. May
- Department of Obstetrics and GynecologyECUGreenvilleNCUSA
- Department of Kinesiology, College of Health and Human PerformanceECUGreenvilleNCUSA
- Foundational Sciences and Research, School of Dental MedicineECUGreenvilleNCUSA
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12
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Arrowsmith S, Keov P, Muttenthaler M, Gruber CW. Contractility Measurements of Human Uterine Smooth Muscle to Aid Drug Development. J Vis Exp 2018. [PMID: 29443077 PMCID: PMC5841565 DOI: 10.3791/56639] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Discovery and characterization of novel pharmaceutical compounds or biochemical probes rely on robust and physiologically relevant assay systems. We describe methods to measure ex vivo myometrium contractility. This assay can be used to investigate factors and molecules involved in the modulation of myometrial contraction and to determine their excitatory or inhibitory actions, and hence their therapeutic potential in vivo. Biopsies are obtained from women undergoing cesarean section delivery with informed consent. Fine strips of myometrium are dissected, clipped and attached to a force transducer within 1 mL organ baths superfused with physiological saline solution at 37 °C. Strips develop spontaneous contractions within 2-3 h under set tension and remain stable for many hours (>6 h). Strips can also be stimulated to contract such as by the endogenous hormones, oxytocin and vasopressin, which cause concentration-dependent modulation of contraction frequency, force and duration, to more closely resemble contractions in labor. Hence, the effect of known and novel drug leads can be tested on spontaneous and agonist-induced contractions. This protocol specifically details how this assay can be used to determine the potency of known and novel agents by measuring their effects on various parameters of human myometrial contraction. We use the oxytocin- and V1a receptor antagonists, atosiban and SR49059 as examples of known compounds which inhibit oxytocin- and vasopressin-induced contractions, and demonstrate how this method can be used to complement and validate pharmacological data obtained from cell-based assays to aid drug development. The effects of novel agonists in comparison to oxytocin and vasopressin can also be characterized. Whilst we use the example of the oxytocin/ vasopressin system, this method can also be used to study other receptors and ion channels that play a role in uterine contraction and relaxation to advance the understanding of human uterine physiology and pathophysiology.
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Affiliation(s)
- Sarah Arrowsmith
- Harris-Wellbeing Preterm Birth Research Centre, Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool;
| | - Peter Keov
- School of Biomedical Sciences, The University of Queensland
| | - Markus Muttenthaler
- Faculty of Chemistry, Institute of Biological Chemistry, University of Vienna; Institute for Molecular Bioscience, University of Queensland
| | - Christian W Gruber
- School of Biomedical Sciences, The University of Queensland; Center for Physiology and Pharmacology, Medical University of Vienna;
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13
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Gam CMBF, Larsen LH, Mortensen OH, Engelbrechtsen L, Poulsen SS, Qvortrup K, Mathiesen ER, Damm P, Quistorff B. Unchanged mitochondrial phenotype, but accumulation of lipids in the myometrium in obese pregnant women. J Physiol 2017; 595:7109-7122. [PMID: 29119568 DOI: 10.1113/jp274838] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 09/13/2017] [Indexed: 12/17/2022] Open
Abstract
KEY POINTS Obesity during pregnancy and childbirth is associated with labour dystocia leading to instrumental or operative delivery, but the underlying pathophysiological mechanisms remain unclear and insufficient uterine contractility has been suggested. This study examined whether reduced myometrial mitochondrial capacity or quantity could contribute as a pathophysiological mechanism to labour dystocia. Data did not support reduced myometrial mitochondrial capacity or quantity in the myometrium at term in obese women, but a reduced myocyte density with increased triglyceride content was demonstrated, which could lead to poorer uterine contractility. These results add to the understanding of systemic effects of obesity, placing also the myometrium at term as an affected non-adipose tissue. ABSTRACT Obesity is known to increase the risk of labour dystocia and insufficient energy supply, due to reduced mitochondrial capacity or quantity, could be a possible mechanism leading to reduced efficiency of uterine contractility during labour. In the present study of 36 women having an elective Caesarean section at term, obesity did not change mitochondrial phenotype in the myometrial myocyte obtained from uterine biopsies taken at delivery. Respiration rates in isolated mitochondria were unaffected by obesity. No indication of reduced content, investigated by quantification of the complexes of the respiratory chain, or altered regulation, examined by myometrial mRNA levels of genes related to mitochondrial biogenesis and inflammation, was detected. Yet we found increased myometrial triglyceride content in the obese group (2.39 ± 0.26 vs. 1.56 ± 0.20 mm, P = 0.024), while protein content and citrate synthase activity per gram wet weight myometrium were significantly lower in the obese (109.2 ± 7.2 vs. 139.4 ± 5.6 mg g-1 , P = 0.002, and 24.8 ± 1.0 vs. 29.6 ± 1.4 U g-1 wet wt, P = 0.008, respectively). These differences were substantiated by our histological findings where staining for nuclei, cytoplasm, glycogen and collagen supported the idea of a smaller muscle content in the myometrium in obese women. In conclusion no indication of myometrial mitochondrial dysfunction in the isolated state was found, but the observed increase of lipid content might play a role in the pathophysiological mechanisms behind labour dystocia in obese women.
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Affiliation(s)
- Christiane Marie Bourgin Folke Gam
- Cellular and Metabolic Research Section, Department of Biomedical Sciences, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, Denmark, 2200.,Center for Pregnant Women with Diabetes, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark, 2100.,Department of Obstetrics, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark, 2100
| | - Lea Hüche Larsen
- Cellular and Metabolic Research Section, Department of Biomedical Sciences, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, Denmark, 2200
| | - Ole Hartvig Mortensen
- Cellular and Metabolic Research Section, Department of Biomedical Sciences, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, Denmark, 2200
| | - Line Engelbrechtsen
- Department of Obstetrics, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark, 2100
| | - Steen Seier Poulsen
- Endocrinology Research Section, Department of Biomedical Sciences, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, Denmark, 2200
| | - Klaus Qvortrup
- Core Facility for Integrated Microscopy, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, Denmark, 2200
| | - Elisabeth Reinhart Mathiesen
- Center for Pregnant Women with Diabetes, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark, 2100.,Department of Endocrinology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark, 2100.,Institute of Clinical Medicine, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, Denmark, 2200
| | - Peter Damm
- Center for Pregnant Women with Diabetes, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark, 2100.,Department of Obstetrics, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark, 2100.,Institute of Clinical Medicine, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, Denmark, 2200
| | - Bjørn Quistorff
- Cellular and Metabolic Research Section, Department of Biomedical Sciences, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, Denmark, 2200
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