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Kane AD, Herrera EA, Niu Y, Camm EJ, Allison BJ, Tijsseling D, Lusby C, Derks JB, Brain KL, Bronckers IM, Cross CM, Berends L, Giussani DA. Combined Statin and Glucocorticoid Therapy for the Safer Treatment of Preterm Birth. Hypertension 2023; 80:837-851. [PMID: 36724801 PMCID: PMC10017302 DOI: 10.1161/hypertensionaha.122.19647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 01/03/2023] [Indexed: 02/03/2023]
Abstract
BACKGROUND Prematurity is strongly associated with poor respiratory function in the neonate. Rescue therapies include treatment with glucocorticoids due to their anti-inflammatory and maturational effects on the developing lung. However, glucocorticoid treatment in the infant can increase the risk of long-term cardiovascular complications including hypertension, cardiac, and endothelial dysfunction. Accumulating evidence implicates a molecular link between glucocorticoid excess and depletion of nitric oxide (NO) bioavailability as a mechanism underlying the detrimental effects of postnatal steroids on the heart and circulation. Therefore, combined glucocorticoid and statin therapy, by increasing NO bioavailability, may protect the developing cardiovascular system while maintaining beneficial effects on the lung. METHODS We investigated combined glucocorticoid and statin therapy using an established rodent model of prematurity and combined experiments of cardiovascular function in vivo, with those in isolated organs as well as measurements at the cellular and molecular levels. RESULTS We show that neonatal glucocorticoid treatment increases the risk of later cardiovascular dysfunction in the offspring. Underlying mechanisms include decreased circulating NO bioavailability, sympathetic hyper-reactivity, and NO-dependent endothelial dysfunction. Combined neonatal glucocorticoid and statin therapy protects the developing cardiovascular system by normalizing NO and sympathetic signaling, without affecting pulmonary maturational or anti-inflammatory effects of glucocorticoids. CONCLUSIONS Therefore, combined glucocorticoid and statin therapy may be safer than glucocorticoids alone for the treatment of preterm birth.
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Affiliation(s)
- Andrew D. Kane
- Department of Physiology, Development and Neuroscience, University of Cambridge, United Kingdom (A.D.K., E.A.H., Y.N., E.J.C., B.J.A., C.L., K.L.B., C.M.C., D.A.G.)
| | - Emilio A. Herrera
- Department of Physiology, Development and Neuroscience, University of Cambridge, United Kingdom (A.D.K., E.A.H., Y.N., E.J.C., B.J.A., C.L., K.L.B., C.M.C., D.A.G.)
- Laboratory of Vascular Function & Reactivity, Pathophysiology Program, ICBM, Faculty of Medicine, Universidad de Chile, Santiago, Chile (E.A.H.)
| | - Youguo Niu
- Department of Physiology, Development and Neuroscience, University of Cambridge, United Kingdom (A.D.K., E.A.H., Y.N., E.J.C., B.J.A., C.L., K.L.B., C.M.C., D.A.G.)
- The Cambridge BHF Centre for Research Excellence, Cambridge, United Kingdom (Y.N., D.A.G.)
- The Cambridge Strategic Research Initiative in Reproduction, Cambridge, United Kingdom (Y.N., D.A.G.)
| | - Emily J. Camm
- Department of Physiology, Development and Neuroscience, University of Cambridge, United Kingdom (A.D.K., E.A.H., Y.N., E.J.C., B.J.A., C.L., K.L.B., C.M.C., D.A.G.)
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia (E.J.C., B.J.A.)
| | - Beth J. Allison
- Department of Physiology, Development and Neuroscience, University of Cambridge, United Kingdom (A.D.K., E.A.H., Y.N., E.J.C., B.J.A., C.L., K.L.B., C.M.C., D.A.G.)
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia (E.J.C., B.J.A.)
| | - Deodata Tijsseling
- Perinatal Center, University Medical Center, Utrecht, the Netherlands (D.T., J.B.D.)
| | - Ciara Lusby
- Department of Physiology, Development and Neuroscience, University of Cambridge, United Kingdom (A.D.K., E.A.H., Y.N., E.J.C., B.J.A., C.L., K.L.B., C.M.C., D.A.G.)
| | - Jan B. Derks
- Perinatal Center, University Medical Center, Utrecht, the Netherlands (D.T., J.B.D.)
| | - Kirsty L. Brain
- Department of Physiology, Development and Neuroscience, University of Cambridge, United Kingdom (A.D.K., E.A.H., Y.N., E.J.C., B.J.A., C.L., K.L.B., C.M.C., D.A.G.)
| | - Inge M. Bronckers
- Department of Obstetrics and Gynecology, Radboud University Nijmegen Medical Centre, the Netherlands (I.M.B.)
| | - Christine M. Cross
- Department of Physiology, Development and Neuroscience, University of Cambridge, United Kingdom (A.D.K., E.A.H., Y.N., E.J.C., B.J.A., C.L., K.L.B., C.M.C., D.A.G.)
| | - Lindsey Berends
- Institute of Metabolic Science, University of Cambridge Metabolic Research Laboratories, Addenbrooke’s Hospital, Cambridge, United Kingdom (L.B.)
| | - Dino A. Giussani
- Department of Physiology, Development and Neuroscience, University of Cambridge, United Kingdom (A.D.K., E.A.H., Y.N., E.J.C., B.J.A., C.L., K.L.B., C.M.C., D.A.G.)
- The Cambridge BHF Centre for Research Excellence, Cambridge, United Kingdom (Y.N., D.A.G.)
- The Cambridge Strategic Research Initiative in Reproduction, Cambridge, United Kingdom (Y.N., D.A.G.)
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Hansell JA, Richter HG, Camm EJ, Herrera EA, Blanco CE, Villamor E, Patey OV, Lock MC, Trafford AW, Galli GLJ, Giussani DA. Maternal melatonin: Effective intervention against developmental programming of cardiovascular dysfunction in adult offspring of complicated pregnancy. J Pineal Res 2022; 72:e12766. [PMID: 34634151 DOI: 10.1111/jpi.12766] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 08/16/2021] [Accepted: 08/26/2021] [Indexed: 12/01/2022]
Abstract
Adopting an integrative approach, by combining studies of cardiovascular function with those at cellular and molecular levels, this study investigated whether maternal treatment with melatonin protects against programmed cardiovascular dysfunction in the offspring using an established rodent model of hypoxic pregnancy. Wistar rats were divided into normoxic (N) or hypoxic (H, 10% O2 ) pregnancy ± melatonin (M) treatment (5 μg·ml-1 .day-1 ) in the maternal drinking water. Hypoxia ± melatonin treatment was from day 15-20 of gestation (term is ca. 22 days). To control for possible effects of maternal hypoxia-induced reductions in maternal food intake, additional dams underwent pregnancy under normoxic conditions but were pair-fed (PF) to the daily amount consumed by hypoxic dams from day 15 of gestation. In one cohort of animals from each experimental group (N, NM, H, HM, PF, PFM), measurements were made at the end of gestation. In another, following delivery of the offspring, investigations were made at adulthood. In both fetal and adult offspring, fixed aorta and hearts were studied stereologically and frozen hearts were processed for molecular studies. In adult offspring, mesenteric vessels were isolated and vascular reactivity determined by in-vitro wire myography. Melatonin treatment during normoxic, hypoxic or pair-fed pregnancy elevated circulating plasma melatonin in the pregnant dam and fetus. Relative to normoxic pregnancy, hypoxic pregnancy increased fetal haematocrit, promoted asymmetric fetal growth restriction and resulted in accelerated postnatal catch-up growth. Whilst fetal offspring of hypoxic pregnancy showed aortic wall thickening, adult offspring of hypoxic pregnancy showed dilated cardiomyopathy. Similarly, whilst cardiac protein expression of eNOS was downregulated in the fetal heart, eNOS protein expression was elevated in the heart of adult offspring of hypoxic pregnancy. Adult offspring of hypoxic pregnancy further showed enhanced mesenteric vasoconstrictor reactivity to phenylephrine and the thromboxane mimetic U46619. The effects of hypoxic pregnancy on cardiovascular remodelling and function in the fetal and adult offspring were independent of hypoxia-induced reductions in maternal food intake. Conversely, the effects of hypoxic pregnancy on fetal and postanal growth were similar in pair-fed pregnancies. Whilst maternal treatment of normoxic or pair-fed pregnancies with melatonin on the offspring cardiovascular system was unremarkable, treatment of hypoxic pregnancies with melatonin in doses lower than those recommended for overcoming jet lag in humans enhanced fetal cardiac eNOS expression and prevented all alterations in cardiovascular structure and function in fetal and adult offspring. Therefore, the data support that melatonin is a potential therapeutic target for clinical intervention against developmental origins of cardiovascular dysfunction in pregnancy complicated by chronic fetal hypoxia.
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Affiliation(s)
- Jeremy A Hansell
- Department of Physiology Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Hans G Richter
- Facultad de Medicina, Instituto de Anatomía, Histología y Patología, Universidad Austral de Chile, Valdivia, Chile
| | - Emily J Camm
- Department of Physiology Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Emilio A Herrera
- Programa de Fisiopatología, Facultad de Medicina, Instituto de Ciencias Biomédicas (ICBM), Universidad de Chile, Santiago, Chile
| | - Carlos E Blanco
- National Children's Research Centre, Our Lady's Children's Hospital, Dublin, Ireland
| | - Eduardo Villamor
- Department of Pediatrics, School for Oncology and Developmental Biology (GROW), Maastricht University Medical Center (MUMC+), Maastricht, The Netherlands
| | - Olga V Patey
- Department of Physiology Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Mitchell C Lock
- Division of Cardiovascular Sciences, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK
| | - Andrew W Trafford
- Division of Cardiovascular Sciences, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK
| | - Gina L J Galli
- Division of Cardiovascular Sciences, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK
| | - Dino A Giussani
- Department of Physiology Development and Neuroscience, University of Cambridge, Cambridge, UK
- Cambridge BHF Centre for Research Excellence, Cambridge, UK
- Cambridge Strategic Research Initiative in Reproduction, Cambridge, UK
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Joseph S, Li M, Zhang S, Horne L, Stacpoole PW, Wohlgemuth SE, Edison AS, Wood C, Keller-Wood M. Sodium dichloroacetate stimulates cardiac mitochondrial metabolism and improves cardiac conduction in the ovine fetus during labor. Am J Physiol Regul Integr Comp Physiol 2022; 322:R83-R98. [PMID: 34851727 PMCID: PMC8791792 DOI: 10.1152/ajpregu.00185.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Previous studies in our laboratory have suggested that the increase in stillbirth in pregnancies complicated by chronic maternal stress or hypercortisolemia is associated with cardiac dysfunction in late stages of labor and delivery. Transcriptomics analysis of the overly represented differentially expressed genes in the fetal heart of hypercortisolemic ewes indicated involvement of mitochondrial function. Sodium dichloroacetate (DCA) has been used to improve mitochondrial function in several disease states. We hypothesized that administration of DCA to laboring ewes would improve both cardiac mitochondrial activity and cardiac function in their fetuses. Four groups of ewes and their fetuses were studied: control, cortisol-infused (1 g/kg/day from 115 to term; CORT), DCA-treated (over 24 h), and DCA + CORT-treated; oxytocin was delivered starting 48 h before the DCA treatment. DCA significantly decreased cardiac lactate, alanine, and glucose/glucose-6-phosphate and increased acetylcarnitine/isobutyryl-carnitine. DCA increased mitochondrial activity, increasing oxidative phosphorylation (PCI, PCI + II) per tissue weight or per unit of citrate synthase. DCA also decreased the duration of the QRS, attenuating the prolongation of the QRS observed in CORT fetuses. The effect to reduce QRS duration with DCA treatment correlated with increased glycerophosphocholine and serine and decreased phosphorylcholine after DCA treatment. There were negative correlations of acetylcarnitine/isobutyryl-carnitine to both heart rate (HR) and mean arterial pressure (MAP). These results suggest that improvements in mitochondrial respiration with DCA produced changes in the cardiac lipid metabolism that favor improved conduction in the heart. DCA may therefore be an effective treatment of fetal cardiac metabolic disturbances in labor that can contribute to impairments of fetal cardiac conduction.
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Affiliation(s)
- Serene Joseph
- 1Department of Pharmacodynamics, University of Florida College of Pharmacy, Gainesville, Florida
| | - Mengchen Li
- 2Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, Florida
| | - Sicong Zhang
- 3Department of Biochemistry and Molecular Biology and Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia
| | - Lloyd Horne
- 4Department of Medicine and Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Gainesville, Florida
| | - Peter. W. Stacpoole
- 4Department of Medicine and Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Gainesville, Florida
| | - Stephanie E. Wohlgemuth
- 5Department of Aging and Geriatric Research, University of Florida College of Medicine, Gainesville, Florida
| | - Arthur S. Edison
- 3Department of Biochemistry and Molecular Biology and Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia
| | - Charles Wood
- 2Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, Florida
| | - Maureen Keller-Wood
- 1Department of Pharmacodynamics, University of Florida College of Pharmacy, Gainesville, Florida
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Abstract
Heart disease remains one of the greatest killers. In addition to genetics and traditional lifestyle risk factors, we now understand that adverse conditions during pregnancy can also increase susceptibility to cardiovascular disease in the offspring. Therefore, the mechanisms by which this occurs and possible preventative therapies are of significant contemporary interest to the cardiovascular community. A common suboptimal pregnancy condition is a sustained reduction in fetal oxygenation. Chronic fetal hypoxia results from any pregnancy with increased placental vascular resistance, such as in preeclampsia, placental infection, or maternal obesity. Chronic fetal hypoxia may also arise during pregnancy at high altitude or because of maternal respiratory disease. This article reviews the short- and long-term effects of hypoxia on the fetal cardiovascular system, and the importance of chronic fetal hypoxia in triggering a developmental origin of future heart disease in the adult progeny. The work summarizes evidence derived from human studies as well as from rodent, avian, and ovine models. There is a focus on the discovery of the molecular link between prenatal hypoxia, oxidative stress, and increased cardiovascular risk in adult offspring. Discussion of mitochondria-targeted antioxidant therapy offers potential targets for clinical intervention in human pregnancy complicated by chronic fetal hypoxia.
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Affiliation(s)
- Dino A Giussani
- Department of Physiology, Development, and Neuroscience; The Barcroft Centre; Cambridge Cardiovascular British Heart Foundation Centre for Research Excellence; and Cambridge Strategic Research Initiative in Reproduction, University of Cambridge, UK
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5
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Tardelli LP, Duchatsch F, Herrera NA, Vicentini CA, Okoshi K, Amaral SL. Differential effects of dexamethasone on arterial stiffness, myocardial remodeling and blood pressure between normotensive and spontaneously hypertensive rats. J Appl Toxicol 2021; 41:1673-1686. [PMID: 33629383 DOI: 10.1002/jat.4155] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 02/01/2021] [Accepted: 02/10/2021] [Indexed: 12/11/2022]
Abstract
Dexamethasone (DEX)-induced hypertension is observed in normotensive rats, but little is known about the effects of DEX on spontaneously hypertensive animals (SHR). This study aimed to evaluate the effects of DEX on hemodynamics, cardiac hypertrophy and arterial stiffness in normotensive and hypertensive rats. Wistar rats and SHR were treated with DEX (50 μg/kg s.c., 14 d) or saline. Pulse wave velocity (PWV), echocardiographic parameters, blood pressure (BP), autonomic modulation and histological analyses of heart and thoracic aorta were performed. SHR had higher BP compared with Wistar, associated with autonomic unbalance to the heart. Echocardiographic changes in SHR (vs. Wistar) were suggestive of cardiac remodeling: higher relative wall thickness (RWT, +28%) and left ventricle mass index (LVMI, +26%) and lower left ventricle systolic diameter (LVSD, -19%) and LV diastolic diameter (LVDD, -10%), with slightly systolic dysfunction and preserved diastolic dysfunction. Also, SHR had lower myocardial capillary density and similar collagen deposition area. PWV was higher in SHR due to higher aortic collagen deposition. DEX-treated Wistar rats presented higher BP (~23%) and autonomic unbalance. DEX did not change cardiac structure in Wistar, but PWV (+21%) and aortic collagen deposition area (+21%) were higher compared with control. On the other side, DEX did not change BP or autonomic balance to the heart in SHR, but reduced RWT and LV collagen deposition area (-12% vs. SHRCT ). In conclusion, the results suggest a differential effect of dexamethasone on arterial stiffness, myocardial remodeling and blood pressure between normotensive and spontaneously hypertensive rats.
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Affiliation(s)
- Lidieli P Tardelli
- Joint Graduate Program in Physiological Sciences, PIPGCF UFSCar/UNESP, São Carlos, Brazil
| | - Francine Duchatsch
- Joint Graduate Program in Physiological Sciences, PIPGCF UFSCar/UNESP, São Carlos, Brazil
| | - Naiara A Herrera
- Joint Graduate Program in Physiological Sciences, PIPGCF UFSCar/UNESP, São Carlos, Brazil
| | | | - Katashi Okoshi
- Department of Medical Clinic, Botucatu Medical School, São Paulo State University (UNESP), Botucatu, Brazil
| | - Sandra L Amaral
- Joint Graduate Program in Physiological Sciences, PIPGCF UFSCar/UNESP, São Carlos, Brazil.,Department of Physical Education, School of Sciences, São Paulo State University (UNESP), Bauru, Brazil
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Fratelli N, Prefumo F, Wolf H, Hecher K, Visser GHA, Giussani D, Derks JB, Shaw CJ, Frusca T, Ghi T, Ferrazzi E, Lees CC. Effects of Antenatal Betamethasone on Fetal Doppler Indices and Short Term Fetal Heart Rate Variation in Early Growth Restricted Fetuses. ULTRASCHALL IN DER MEDIZIN (STUTTGART, GERMANY : 1980) 2021; 42:56-64. [PMID: 31476786 DOI: 10.1055/a-0972-1098] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
PURPOSE To investigate the effects of the antenatal administration of betamethasone on fetal Doppler and short term fetal heart rate variation (CTG-STV) in early growth restricted (FGR) fetuses. MATERIALS AND METHODS Post hoc analysis of data derived from the TRUFFLE study, a prospective, multicenter, randomized management trial of severe early onset FGR. Repeat Doppler and CTG-STV measurements between the last recording within 48 hours before the first dose of betamethasone (baseline value) and for 10 days after were evaluated. Multilevel analysis was performed to analyze the longitudinal course of the umbilico-cerebral ratio (UC ratio), the ductus venosus pulsatility index (DVPIV) and CTG-STV. RESULTS We included 115 fetuses. A significant increase from baseline in CTG-STV was found on day + 1 (p = 0.019) but no difference thereafter. The DVPIV was not significantly different from baseline in any of the 10 days following the first dose of betamethasone (p = 0.167). Multilevel analysis revealed that, over 10 days, the time elapsed from antenatal administration of betamethasone was significantly associated with a decrease in CTG-STV (p = 0.045) and an increase in the DVPIV (p = 0.001) and UC ratio (p < 0.001). CONCLUSION Although steroid administration in early FGR has a minimal effect on increasing CTG-STV one day afterwards, the effects on Doppler parameters were extremely slight with regression coefficients of small magnitude suggesting no clinical significance, and were most likely related to the deterioration with time in FGR. Hence, arterial and venous Doppler assessment of fetal health remains informative following antenatal steroid administration to accelerate fetal lung maturation.
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Affiliation(s)
- Nicola Fratelli
- Department of Obstetrics and Gynaecology, University of Brescia, Spedali Civili di Brescia, Brescia, Italy
| | - Federico Prefumo
- Department of Obstetrics and Gynaecology, University of Brescia, Spedali Civili di Brescia, Brescia, Italy
| | - Hans Wolf
- Department of Obstetrics and Gynecology, Academic Medical Centre, Amsterdam, Netherlands
| | - Kurt Hecher
- Department of Obstetrics and Fetal Medicine, University Medical Center, Hamburg-Eppendorf, Germany
| | - Gerard H A Visser
- Department of Perinatal Medicine, University of Utrecht, Netherlands
| | - Dino Giussani
- Department of Physiology Development & Neuroscience, University of Cambridge, United Kingdom of Great Britain and Northern Ireland
| | - Jan B Derks
- Department of Perinatal Medicine, University of Utrecht, Netherlands
| | - Caroline J Shaw
- Department of Surgery and Cancer, Imperial College London, United Kingdom of Great Britain and Northern Ireland
| | - Tiziana Frusca
- Department of Surgical Sciences, Obstetrics and Gynecology Unit, University of Parma, Italy
| | - Tullio Ghi
- Department of Surgical Sciences, Obstetrics and Gynecology Unit, University of Parma, Italy
| | - E Ferrazzi
- Children's Hospital Buzzi, University of Milan, Italy
| | - Christoph C Lees
- Department of Surgery and Cancer, Imperial College London, United Kingdom of Great Britain and Northern Ireland
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Lear CA, Davidson JO, Dhillon SK, King VJ, Lear BA, Magawa S, Maeda Y, Ikeda T, Gunn AJ, Bennet L. Effects of antenatal dexamethasone and hyperglycemia on cardiovascular adaptation to asphyxia in preterm fetal sheep. Am J Physiol Regul Integr Comp Physiol 2020; 319:R653-R665. [PMID: 33074015 DOI: 10.1152/ajpregu.00216.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Antenatal glucocorticoids improve outcomes among premature infants but are associated with hyperglycemia, which can exacerbate hypoxic-ischemic injury. It is still unclear how antenatal glucocorticoids or hyperglycemia modulate fetal cardiovascular adaptations to severe asphyxia. In this study, preterm fetal sheep received either saline or 12 mg im maternal dexamethasone, followed 4 h later by complete umbilical cord occlusion (UCO) for 25 min. An additional cohort of fetuses received titrated glucose infusions followed 4 h later by UCO to control for the possibility that hyperglycemia contributed to the cardiovascular effects of dexamethasone. Fetuses were studied for 7 days after UCO. Maternal dexamethasone was associated with fetal hyperglycemia (P < 0.001), increased arterial pressure (P < 0.001), and reduced femoral (P < 0.005) and carotid (P < 0.05) vascular conductance before UCO. UCO was associated with bradycardia, femoral vasoconstriction, and transient hypertension. For the first 5 min of UCO, fetal blood pressure in the dexamethasone-asphyxia group was greater than saline-asphyxia (P < 0.001). However, the relative increase in arterial pressure was not different from saline-asphyxia. Fetal heart rate and femoral vascular conductance fell to similar nadirs in both saline and dexamethasone-asphyxia groups. Dexamethasone did not affect the progressive decline in femoral vascular tone or arterial pressure during continuing UCO. By contrast, there were no effects of glucose infusions on the response to UCO. In summary, maternal dexamethasone but not fetal hyperglycemia increased fetal arterial pressure before and for the first 5 min of prolonged UCO but did not augment the cardiovascular adaptations to acute asphyxia.
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Affiliation(s)
- Christopher A Lear
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Joanne O Davidson
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Simerdeep K Dhillon
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Victoria J King
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Benjamin A Lear
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Shoichi Magawa
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand.,Department of Obstetrics and Gynecology, Mie University, Mie, Japan
| | - Yoshiki Maeda
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand.,Department of Obstetrics and Gynecology, Mie University, Mie, Japan
| | - Tomoaki Ikeda
- Department of Obstetrics and Gynecology, Mie University, Mie, Japan
| | - Alistair J Gunn
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Laura Bennet
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
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8
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Allison BJ, Brain KL, Niu Y, Kane AD, Herrera EA, Thakor AS, Botting KJ, Cross CM, Itani N, Shaw CJ, Skeffington KL, Beck C, Giussani DA. Altered Cardiovascular Defense to Hypotensive Stress in the Chronically Hypoxic Fetus. Hypertension 2020; 76:1195-1207. [PMID: 32862711 PMCID: PMC7480941 DOI: 10.1161/hypertensionaha.120.15384] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Supplemental Digital Content is available in the text. The hypoxic fetus is at greater risk of cardiovascular demise during a challenge, but the reasons behind this are unknown. Clinically, progress has been hampered by the inability to study the human fetus non-invasively for long period of gestation. Using experimental animals, there has also been an inability to induce gestational hypoxia while recording fetal cardiovascular function as the hypoxic pregnancy is occurring. We use novel technology in sheep pregnancy that combines induction of controlled chronic hypoxia with simultaneous, wireless recording of blood pressure and blood flow signals from the fetus. Here, we investigated the cardiovascular defense of the hypoxic fetus to superimposed acute hypotension. Pregnant ewes carrying singleton fetuses surgically prepared with catheters and flow probes were randomly exposed to normoxia or chronic hypoxia from 121±1 days of gestation (term ≈145 days). After 10 days of exposure, fetuses were subjected to acute hypotension via fetal nitroprusside intravenous infusion. Underlying in vivo mechanisms were explored by (1) analyzing fetal cardiac and peripheral vasomotor baroreflex function; (2) measuring the fetal plasma catecholamines; and (3) establishing fetal femoral vasoconstrictor responses to the α1-adrenergic agonist phenylephrine. Relative to controls, chronically hypoxic fetal sheep had reversed cardiac and impaired vasomotor baroreflex function, despite similar noradrenaline and greater adrenaline increments in plasma during hypotension. Chronic hypoxia markedly diminished the fetal vasopressor responses to phenylephrine. Therefore, we show that the chronically hypoxic fetus displays markedly different cardiovascular responses to acute hypotension, providing in vivo evidence of mechanisms linking its greater susceptibility to superimposed stress.
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Affiliation(s)
- Beth J Allison
- From the Department of Physiology, Development and Neuroscience, University of Cambridge, United Kingdom (B.J.A., K.L.B., Y.N., A.D.K., E.A.H., A.S.T., K.J.B., C.M.C., N.I., C.J.S., K.L.S., C.B., D.A.G.)
| | - Kirsty L Brain
- From the Department of Physiology, Development and Neuroscience, University of Cambridge, United Kingdom (B.J.A., K.L.B., Y.N., A.D.K., E.A.H., A.S.T., K.J.B., C.M.C., N.I., C.J.S., K.L.S., C.B., D.A.G.)
| | - Youguo Niu
- From the Department of Physiology, Development and Neuroscience, University of Cambridge, United Kingdom (B.J.A., K.L.B., Y.N., A.D.K., E.A.H., A.S.T., K.J.B., C.M.C., N.I., C.J.S., K.L.S., C.B., D.A.G.)
| | - Andrew D Kane
- From the Department of Physiology, Development and Neuroscience, University of Cambridge, United Kingdom (B.J.A., K.L.B., Y.N., A.D.K., E.A.H., A.S.T., K.J.B., C.M.C., N.I., C.J.S., K.L.S., C.B., D.A.G.)
| | | | - Avnesh S Thakor
- From the Department of Physiology, Development and Neuroscience, University of Cambridge, United Kingdom (B.J.A., K.L.B., Y.N., A.D.K., E.A.H., A.S.T., K.J.B., C.M.C., N.I., C.J.S., K.L.S., C.B., D.A.G.)
| | - Kimberley J Botting
- From the Department of Physiology, Development and Neuroscience, University of Cambridge, United Kingdom (B.J.A., K.L.B., Y.N., A.D.K., E.A.H., A.S.T., K.J.B., C.M.C., N.I., C.J.S., K.L.S., C.B., D.A.G.)
| | - Christine M Cross
- From the Department of Physiology, Development and Neuroscience, University of Cambridge, United Kingdom (B.J.A., K.L.B., Y.N., A.D.K., E.A.H., A.S.T., K.J.B., C.M.C., N.I., C.J.S., K.L.S., C.B., D.A.G.)
| | - Nozomi Itani
- From the Department of Physiology, Development and Neuroscience, University of Cambridge, United Kingdom (B.J.A., K.L.B., Y.N., A.D.K., E.A.H., A.S.T., K.J.B., C.M.C., N.I., C.J.S., K.L.S., C.B., D.A.G.)
| | - Caroline J Shaw
- From the Department of Physiology, Development and Neuroscience, University of Cambridge, United Kingdom (B.J.A., K.L.B., Y.N., A.D.K., E.A.H., A.S.T., K.J.B., C.M.C., N.I., C.J.S., K.L.S., C.B., D.A.G.).,Institute of Reproductive and Developmental Biology, Imperial College, London United Kingdom (C.J.S.)
| | - Katie L Skeffington
- From the Department of Physiology, Development and Neuroscience, University of Cambridge, United Kingdom (B.J.A., K.L.B., Y.N., A.D.K., E.A.H., A.S.T., K.J.B., C.M.C., N.I., C.J.S., K.L.S., C.B., D.A.G.)
| | - Chritian Beck
- From the Department of Physiology, Development and Neuroscience, University of Cambridge, United Kingdom (B.J.A., K.L.B., Y.N., A.D.K., E.A.H., A.S.T., K.J.B., C.M.C., N.I., C.J.S., K.L.S., C.B., D.A.G.)
| | - Dino A Giussani
- From the Department of Physiology, Development and Neuroscience, University of Cambridge, United Kingdom (B.J.A., K.L.B., Y.N., A.D.K., E.A.H., A.S.T., K.J.B., C.M.C., N.I., C.J.S., K.L.S., C.B., D.A.G.).,Cambridge Cardiovascular Strategic Research Initiative (D.A.G.).,Cambridge Strategic Research Initiative in Reproduction (D.A.G.)
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9
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Shaw CJ, Rivens I, Civale J, Botting KJ, Allison BJ, Brain KL, Niu Y, Ter Haar G, Giussani DA, Lees CC. Maternal and fetal cardiometabolic recovery following ultrasound-guided high-intensity focused ultrasound placental vascular occlusion. J R Soc Interface 2020; 16:20190013. [PMID: 31039691 PMCID: PMC6544891 DOI: 10.1098/rsif.2019.0013] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
High-intensity focused ultrasound (HIFU) is a non-invasive method of selective placental vascular occlusion, providing a potential therapy for conditions such as twin–twin transfusion syndrome. In order to translate this technique into human studies, evidence of prolonged fetal recovery and maintenance of a healthy fetal physiology following exposure to HIFU is essential. At 116 ± 2 days gestation, 12 pregnant ewes were assigned to control (n = 6) or HIFU vascular occlusion (n = 6) groups and anaesthetized. Placental blood vessels were identified using colour Doppler ultrasound; HIFU-mediated vascular occlusion was performed through intact maternal skin (1.66 MHz, 5 s duration, in situ ISPTA 1.8–3.9 kW cm−2). Unidentifiable colour Doppler signals in targeted vessels following HIFU exposure denoted successful occlusion. Ewes and fetuses were then surgically instrumented with vascular catheters and transonic flow probes and recovered from anaesthesia. A custom-made wireless data acquisition system, which records continuous maternal and fetal cardiovascular data, and daily blood sampling were used to assess wellbeing for 20 days, followed by post-mortem examination. Based on a comparison of pre- and post-treatment colour Doppler imaging, 100% (36/36) of placental vessels were occluded following HIFU, and occlusion persisted for 20 days. All fetuses survived. No differences in maternal or fetal blood pressure, heart rate, heart rate variability, metabolic status or oxygenation were observed between treatment groups. There was evidence of normal fetal maturation and no evidence of chronic fetal stress. There were no maternal injuries and no placental vascular haemorrhage. There was both a uterine and fetal burn, which did not result in any obstetric or fetal complications. This study demonstrates normal long-term recovery of fetal sheep from exposure to HIFU-mediated placental vascular occlusion and underlines the potential of HIFU as a potential non-invasive therapy in human pregnancy.
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Affiliation(s)
- Caroline J Shaw
- 1 Department of Physiology, Development and Neuroscience, University of Cambridge , Cambridge CB2 3EG , UK.,2 Institute of Reproductive and Developmental Biology, Imperial College London , London W12 0HS , UK
| | - Ian Rivens
- 3 Joint Department of Physics, Institute of Cancer Research , Sutton SM2 5NG , UK
| | - John Civale
- 3 Joint Department of Physics, Institute of Cancer Research , Sutton SM2 5NG , UK
| | - Kimberley J Botting
- 1 Department of Physiology, Development and Neuroscience, University of Cambridge , Cambridge CB2 3EG , UK.,4 Cardiovascular Strategic Research Initiative, University of Cambridge , Cambridge , UK
| | - Beth J Allison
- 1 Department of Physiology, Development and Neuroscience, University of Cambridge , Cambridge CB2 3EG , UK
| | - Kirsty L Brain
- 1 Department of Physiology, Development and Neuroscience, University of Cambridge , Cambridge CB2 3EG , UK
| | - Y Niu
- 1 Department of Physiology, Development and Neuroscience, University of Cambridge , Cambridge CB2 3EG , UK.,4 Cardiovascular Strategic Research Initiative, University of Cambridge , Cambridge , UK
| | - Gail Ter Haar
- 3 Joint Department of Physics, Institute of Cancer Research , Sutton SM2 5NG , UK
| | - Dino A Giussani
- 1 Department of Physiology, Development and Neuroscience, University of Cambridge , Cambridge CB2 3EG , UK.,4 Cardiovascular Strategic Research Initiative, University of Cambridge , Cambridge , UK
| | - Christoph C Lees
- 2 Institute of Reproductive and Developmental Biology, Imperial College London , London W12 0HS , UK.,5 Department of Obstetrics and Gynaecology, University Hospitals Leuven , 3000 Leuven , Belgium
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10
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Varcoe TJ, Darby JRT, Holman SL, Bradshaw EL, Kuchel T, Vaughan L, Seed M, Wiese MD, Morrison JL. Fetal cardiovascular response to acute hypoxia during maternal anesthesia. Physiol Rep 2020; 8:e14365. [PMID: 32026576 PMCID: PMC7002532 DOI: 10.14814/phy2.14365] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Accepted: 01/03/2020] [Indexed: 12/23/2022] Open
Abstract
Preclinical imaging studies of fetal hemodynamics require anesthesia to immobilize the animal. This may induce cardiovascular depression and confound measures under investigation. We compared the impact of four anesthetic regimes upon maternal and fetal blood gas and hemodynamics during baseline periods of normoxia, and in response to an acute hypoxic challenge in pregnant sheep. Merino ewes were surgically prepared with maternal and fetal vascular catheters and a fetal femoral artery flow probe at 105-109 days gestation. At 110-120 days gestation, ewes were anesthetized with either isoflurane (1.6%), isoflurane (0.8%) plus ketamine (3.6 mg·kg-1 ·h-1 ), ketamine (12.6 mg·kg-1 ·h-1 ) plus midazolam (0.78 mg·kg-1 ·h-1 ), propofol (30 mg·kg-1 ·h-1 ), or remained conscious. Following 60 min of baseline recording, nitrogen was administered directly into the maternal trachea to displace oxygen and induce maternal and thus fetal hypoxemia. During normoxia, maternal PaO2 was ~30 mmHg lower in anesthetized ewes compared to conscious controls, regardless of the type of anesthesia (p < .001). There was no effect of anesthesia on fetal mean arterial blood pressure (MAP; p > .05), but heart rate was 32 ± 8 bpm lower in fetuses from ewes administered isoflurane (p = .044). During maternal hypoxia, fetal MAP increased, and peripheral blood flow decreased in all fetuses except those administered propofol (p < .05). Unexpectedly, hypoxemia also induced fetal tachycardia regardless of the anesthetic regime (p < .05). These results indicate that despite maternal anesthesia, the fetus can mount a cardiovascular response to acute hypoxia by increasing blood pressure and reducing peripheral blood flow, although the heart rate response may differ from when no anesthesia is present.
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Affiliation(s)
- Tamara J. Varcoe
- Early Origins of Adult Health Research GroupUniversity of South AustraliaAdelaideAustralia
- School of Pharmacy and Medical SciencesUniversity of South AustraliaAdelaideAustralia
| | - Jack R. T. Darby
- Early Origins of Adult Health Research GroupUniversity of South AustraliaAdelaideAustralia
- School of Pharmacy and Medical SciencesUniversity of South AustraliaAdelaideAustralia
| | - Stacey L. Holman
- Early Origins of Adult Health Research GroupUniversity of South AustraliaAdelaideAustralia
- School of Pharmacy and Medical SciencesUniversity of South AustraliaAdelaideAustralia
| | - Emma L. Bradshaw
- Early Origins of Adult Health Research GroupUniversity of South AustraliaAdelaideAustralia
- School of Pharmacy and Medical SciencesUniversity of South AustraliaAdelaideAustralia
| | - Tim Kuchel
- South Australian Health and Medical Research InstituteAdelaideAustralia
| | - Lewis Vaughan
- South Australian Health and Medical Research InstituteAdelaideAustralia
| | | | - Michael D. Wiese
- School of Pharmacy and Medical SciencesUniversity of South AustraliaAdelaideAustralia
| | - Janna L. Morrison
- Early Origins of Adult Health Research GroupUniversity of South AustraliaAdelaideAustralia
- School of Pharmacy and Medical SciencesUniversity of South AustraliaAdelaideAustralia
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11
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Jellyman JK, Fletcher AJW, Fowden AL, Giussani DA. Glucocorticoid Maturation of Fetal Cardiovascular Function. Trends Mol Med 2020; 26:170-184. [PMID: 31718939 DOI: 10.1016/j.molmed.2019.09.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 09/17/2019] [Accepted: 09/30/2019] [Indexed: 12/27/2022]
Abstract
The last decade has seen rapid advances in the understanding of the central role of glucocorticoids in preparing the fetus for life after birth. However, relative to other organ systems, maturation by glucocorticoids of the fetal cardiovascular system has been ignored. Here, we review the effects of glucocorticoids on fetal basal cardiovascular function and on the fetal cardiovascular defense responses to acute stress. This is important because glucocorticoid-driven maturational changes in fetal cardiovascular function under basal and stressful conditions are central to the successful transition from intra- to extrauterine life. The cost-benefit balance for the cardiovascular health of the preterm baby of antenatal glucocorticoid therapy administered to pregnant women threatened with preterm birth is also discussed.
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Affiliation(s)
- Juanita K Jellyman
- Department of Biological Sciences, California State Polytechnic University, Pomona, CA, USA.
| | | | - Abigail L Fowden
- Department of Physiology Development and Neuroscience, University of Cambridge, Cambridge, UK; Cambridge Cardiovascular Strategic Research Initiative, Cambridge, UK; Cambridge Strategic Research Initiative in Reproduction, Cambridge, UK
| | - Dino A Giussani
- Department of Physiology Development and Neuroscience, University of Cambridge, Cambridge, UK; Cambridge Cardiovascular Strategic Research Initiative, Cambridge, UK; Cambridge Strategic Research Initiative in Reproduction, Cambridge, UK.
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12
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Garrud TAC, Giussani DA. Combined Antioxidant and Glucocorticoid Therapy for Safer Treatment of Preterm Birth. Trends Endocrinol Metab 2019; 30:258-269. [PMID: 30850263 DOI: 10.1016/j.tem.2019.02.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 01/31/2019] [Accepted: 02/05/2019] [Indexed: 12/31/2022]
Abstract
Ante- and postnatal glucocorticoid therapy reduces morbidity and mortality in the preterm infant, and it is therefore one of the best examples of the successful translation of basic experimental science into human clinical practice. However, accruing evidence derived from human clinical studies and from experimental studies in animal models raise serious concerns about potential long-term adverse effects of treatment on growth and neurological and cardiovascular function in the offspring. This review explores whether combined antioxidant and glucocorticoid therapy may be safer than glucocorticoid therapy alone for the treatment of preterm birth.
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Affiliation(s)
- Tessa A C Garrud
- Department of Physiology Development & Neuroscience, University of Cambridge, Cambridge, UK; Cambridge Cardiovascular Strategic Research Initiative, University of Cambridge, Cambridge, UK; Cambridge Strategic Research Initiative on Reproduction, University of Cambridge, Cambridge, UK
| | - Dino A Giussani
- Department of Physiology Development & Neuroscience, University of Cambridge, Cambridge, UK; Cambridge Cardiovascular Strategic Research Initiative, University of Cambridge, Cambridge, UK; Cambridge Strategic Research Initiative on Reproduction, University of Cambridge, Cambridge, UK.
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13
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Shaw CJ, Allison BJ, Itani N, Botting KJ, Niu Y, Lees CC, Giussani DA. Altered autonomic control of heart rate variability in the chronically hypoxic fetus. J Physiol 2018; 596:6105-6119. [PMID: 29604064 PMCID: PMC6265555 DOI: 10.1113/jp275659] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 03/19/2018] [Indexed: 12/28/2022] Open
Abstract
KEY POINTS Fetal heart rate variability (FHRV) has long been recognised as a powerful predictor of fetal wellbeing, and a decrease in FHRV is associated with fetal compromise. However, the mechanisms by which FHRV is reduced in the chronically hypoxic fetus have yet to be established. The sympathetic and parasympathetic influences on heart rate mature at different rates throughout fetal life, and can be assessed by time domain and power spectral analysis of FHRV. In this study of chronically instrumented fetal sheep in late gestation, we analysed FHRV daily over a 16 day period towards term, and compared changes between fetuses of control and chronically hypoxic pregnancy. We show that FHRV in sheep is reduced by chronic hypoxia, predominantly due to dysregulation of the sympathetic control of the fetal heart rate. This presents a potential mechanism by which a reduction in indices of FHRV predicts fetuses at increased risk of neonatal morbidity and mortality in humans. Reduction in overall FHRV may therefore provide a biomarker that autonomic dysregulation of fetal heart rate control has taken place in a fetus where uteroplacental dysfunction is suspected. ABSTRACT Although fetal heart rate variability (FHRV) has long been recognised as a powerful predictor of fetal wellbeing, the mechanisms by which it is reduced in the chronically hypoxic fetus have yet to be established. In particular, the physiological mechanism underlying the reduction of short term variation (STV) in fetal compromise remains unclear. In this study, we present a longitudinal study of the development of autonomic control of FHRV, assessed by indirect indices, time domain and power spectral analysis, in normoxic and chronically hypoxic, chronically catheterised, singleton fetal sheep over the last third of gestation. We used isobaric chambers able to maintain pregnant sheep for prolonged periods in hypoxic conditions (stable fetal femoral arterial P O 2 10-12 mmHg), and a customised wireless data acquisition system to record beat-to-beat variation in the fetal heart rate. We determined in vivo longitudinal changes in overall FHRV and the sympathetic and parasympathetic contribution to FHRV in hypoxic (n = 6) and normoxic (n = 6) ovine fetuses with advancing gestational age. Normoxic fetuses show gestational age-related increases in overall indices of FHRV, and in the sympathetic nervous system contribution to FHRV (P < 0.001). Conversely, gestational age-related increases in overall FHRV were impaired by exposure to chronic hypoxia, and there was evidence of suppression of the sympathetic nervous system control of FHRV after 72 h of exposure to hypoxia (P < 0.001). This demonstrates that exposure to late gestation isolated chronic fetal hypoxia has the potential to alter the development of the autonomic nervous system control of FHRV in sheep. This presents a potential mechanism by which a reduction in indices of FHRV in human fetuses affected by uteroplacental dysfunction can predict fetuses at increased risk.
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Affiliation(s)
- C. J. Shaw
- Department of Physiology, Development and NeuroscienceUniversity of CambridgeCambridgeUK
- Institute of Reproductive and Developmental BiologyImperial College LondonLondonUK
| | - B. J. Allison
- Department of Physiology, Development and NeuroscienceUniversity of CambridgeCambridgeUK
| | - N. Itani
- Department of Physiology, Development and NeuroscienceUniversity of CambridgeCambridgeUK
| | - K. J. Botting
- Department of Physiology, Development and NeuroscienceUniversity of CambridgeCambridgeUK
- Cambridge Cardiovascular Research InitiativeAddenbrooke's HospitalCambridgeUK
| | - Y. Niu
- Department of Physiology, Development and NeuroscienceUniversity of CambridgeCambridgeUK
- Cambridge Cardiovascular Research InitiativeAddenbrooke's HospitalCambridgeUK
| | - C. C. Lees
- Institute of Reproductive and Developmental BiologyImperial College LondonLondonUK
- Department of Obstetrics and GynaecologyUniversity Hospitals LeuvenLeuvenBelgium
| | - D. A. Giussani
- Department of Physiology, Development and NeuroscienceUniversity of CambridgeCambridgeUK
- Cambridge Cardiovascular Research InitiativeAddenbrooke's HospitalCambridgeUK
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14
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Lear CA, Wassink G, Westgate JA, Nijhuis JG, Ugwumadu A, Galinsky R, Bennet L, Gunn AJ. The peripheral chemoreflex: indefatigable guardian of fetal physiological adaptation to labour. J Physiol 2018; 596:5611-5623. [PMID: 29604081 DOI: 10.1113/jp274937] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 03/29/2018] [Indexed: 01/10/2023] Open
Abstract
The fetus is consistently exposed to repeated periods of impaired oxygen (hypoxaemia) and nutrient supply in labour. This is balanced by the healthy fetus's remarkable anaerobic tolerance and impressive ability to mount protective adaptations to hypoxaemia. The most important mediator of fetal adaptations to brief repeated hypoxaemia is the peripheral chemoreflex, a rapid reflex response to acute falls in arterial oxygen tension. The overwhelming majority of fetuses are able to respond to repeated uterine contractions without developing hypotension or hypoxic-ischaemic injury. In contrast, fetuses who are either exposed to severe hypoxaemia, for example during uterine hyperstimulation, or enter labour with reduced anaerobic reserve (e.g. as shown by severe fetal growth restriction) are at increased risk of developing intermittent hypotension and cerebral hypoperfusion. It is remarkable to note that when fetuses develop hypotension during such repeated severe hypoxaemia, it is not mediated by impaired reflex adaptation, but by failure to maintain combined ventricular output, likely due to a combination of exhaustion of myocardial glycogen and evolving myocardial injury. The chemoreflex is suppressed by relatively long periods of severe hypoxaemia of 1.5-2 min, longer than the typical contraction. Even in this setting, the peripheral chemoreflex is consistently reactivated between contractions. These findings demonstrate that the peripheral chemoreflex is an indefatigable guardian of fetal adaptation to labour.
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Affiliation(s)
- Christopher A Lear
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Guido Wassink
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Jenny A Westgate
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand.,Department of Obstetrics and Gynaecology, The University of Auckland, Auckland, New Zealand
| | - Jan G Nijhuis
- Department of Obstetrics and Gynaecology, GROW School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht, the Netherlands
| | - Austin Ugwumadu
- Department of Obstetrics and Gynaecology, St George's, University of London, London, UK
| | - Robert Galinsky
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Laura Bennet
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Alistair J Gunn
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
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15
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Antolic A, Wood CE, Keller-Wood M. Chronic maternal hypercortisolemia in late gestation alters fetal cardiac function at birth. Am J Physiol Regul Integr Comp Physiol 2017; 314:R342-R352. [PMID: 29092858 DOI: 10.1152/ajpregu.00296.2017] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Studies in our laboratory have shown that modest chronic increases in maternal cortisol concentrations over the last 0.20 of gestation impair maternal glucose metabolism and increase the incidence of perinatal stillbirth. Previous studies had found that an increase in maternal cortisol concentrations from 115 to 130 days of gestation in sheep increased both proliferation in fetal cardiomyocytes and apoptosis in the fetal cardiac Purkinje fibers. We hypothesized that the adverse effects of excess cortisol may result in defects in cardiac conduction during labor and delivery. In the present study, we infused cortisol (1 mg·kg-1·day-1) into late gestation pregnant ewes and continuously monitored fetal aortic pressure and ECG through labor and delivery. We found that, although the fetuses of cortisol infused ewes had normal late gestation patterns of arterial pressure and heart rate, there was a significant decrease in fetal aortic pressure and heart rate on the day of birth, specifically in the final hour before delivery. Significant changes in the fetal ECG were also apparent on the day of birth, including prolongation of the P wave and P-R interval. We speculate that chronic exposure to glucocorticoids alters cardiac metabolism or ion homeostasis, contributing to cardiac dysfunction, precipitated by active labor and delivery.
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Affiliation(s)
- Andrew Antolic
- Department of Pharmacodynamics, University of Florida , Gainesville, Florida
| | - Charles E Wood
- Department of Physiology and Functional Genomics, University of Florida , Gainesville, Florida
| | - Maureen Keller-Wood
- Department of Pharmacodynamics, University of Florida , Gainesville, Florida
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16
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Giussani DA. Mind the gap: fetal physiology from bench to bedside. Acta Obstet Gynecol Scand 2016; 95:617-20. [PMID: 27273234 DOI: 10.1111/aogs.12926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Dino A Giussani
- Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge, UK
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17
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Lear CA, Galinsky R, Wassink G, Yamaguchi K, Davidson JO, Westgate JA, Bennet L, Gunn AJ. The myths and physiology surrounding intrapartum decelerations: the critical role of the peripheral chemoreflex. J Physiol 2016; 594:4711-25. [PMID: 27328617 DOI: 10.1113/jp271205] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2015] [Accepted: 02/17/2016] [Indexed: 11/08/2022] Open
Abstract
A distinctive pattern of recurrent rapid falls in fetal heart rate, called decelerations, are commonly associated with uterine contractions during labour. These brief decelerations are mediated by vagal activation. The reflex triggering this vagal response has been variably attributed to a mechanoreceptor response to fetal head compression, to baroreflex activation following increased blood pressure during umbilical cord compression, and/or a Bezold-Jarisch reflex response to reduced venous return from the placenta. Although these complex explanations are still widespread today, there is no consistent evidence that they are common during labour. Instead, the only mechanism that has been systematically investigated, proven to be reliably active during labour and, crucially, capable of producing rapid decelerations is the peripheral chemoreflex. The peripheral chemoreflex is triggered by transient periods of asphyxia that are a normal phenomenon associated with all uterine contractions. This should not cause concern as the healthy fetus has a remarkable ability to adapt to these repeated but short periods of asphyxia. This means that the healthy fetus is typically not at risk of hypotension and injury during uncomplicated labour even during repeated brief decelerations. The physiologically incorrect theories surrounding decelerations that ignore the natural occurrence of repeated asphyxia probably gained widespread support to help explain why many babies are born healthy despite repeated decelerations during labour. We propose that a unified and physiological understanding of intrapartum decelerations that accepts the true nature of labour is critical to improve interpretation of intrapartum fetal heart rate patterns.
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Affiliation(s)
- Christopher A Lear
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Robert Galinsky
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Guido Wassink
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Kyohei Yamaguchi
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand.,Department of Obstetrics and Gynaecology, Mie University Graduate School of Medicine, Mie, Japan
| | - Joanne O Davidson
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Jenny A Westgate
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand.,Department of Obstetrics and Gynaecology, The University of Auckland, Auckland, New Zealand
| | - Laura Bennet
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Alistair J Gunn
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand.,Starship Children's Hospital, Auckland, New Zealand
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18
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Giussani DA. The fetal brain sparing response to hypoxia: physiological mechanisms. J Physiol 2016; 594:1215-30. [PMID: 26496004 DOI: 10.1113/jp271099] [Citation(s) in RCA: 224] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 10/12/2015] [Indexed: 01/13/2023] Open
Abstract
How the fetus withstands an environment of reduced oxygenation during life in the womb has been a vibrant area of research since this field was introduced by Joseph Barcroft, a century ago. Studies spanning five decades have since used the chronically instrumented fetal sheep preparation to investigate the fetal compensatory responses to hypoxia. This defence is contingent on the fetal cardiovascular system, which in late gestation adopts strategies to decrease oxygen consumption and redistribute the cardiac output away from peripheral vascular beds and towards essential circulations, such as those perfusing the brain. The introduction of simultaneous measurement of blood flow in the fetal carotid and femoral circulations by ultrasonic transducers has permitted investigation of the dynamics of the fetal brain sparing response for the first time. Now we know that major components of fetal brain sparing during acute hypoxia are triggered exclusively by a carotid chemoreflex and that they are modified by endocrine agents and the recently discovered vascular oxidant tone. The latter is determined by the interaction between nitric oxide and reactive oxygen species. The fetal brain sparing response matures as the fetus approaches term, in association with the prepartum increase in fetal plasma cortisol, and treatment of the preterm fetus with clinically relevant doses of synthetic steroids mimics this maturation. Despite intense interest into how the fetal brain sparing response may be affected by adverse intrauterine conditions, this area of research has been comparatively scant, but it is likely to take centre stage in the near future.
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Affiliation(s)
- Dino A Giussani
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3EG, UK
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19
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Fowden AL, Forhead AJ. Glucocorticoids as regulatory signals during intrauterine development. Exp Physiol 2015; 100:1477-87. [PMID: 26040783 DOI: 10.1113/ep085212] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 05/22/2015] [Indexed: 01/03/2023]
Abstract
NEW FINDINGS What is the topic of this review? This review discusses the role of the glucocorticoids as regulatory signals during intrauterine development. It examines the functional significance of these hormones as maturational, environmental and programming signals in determining offspring phenotype. What advances does it highlight? It focuses on the extensive nature of the regulatory actions of these hormones. It highlights the emerging data that these actions are mediated, in part, by the placenta, other endocrine systems and epigenetic modifications of the genome. Glucocorticoids are important regulatory signals during intrauterine development. They act as maturational, environmental and programming signals that modify the developing phenotype to optimize offspring viability and fitness. They affect development of a wide range of fetal tissues by inducing changes in cellular expression of structural, transport and signalling proteins, which have widespread functional consequences at the whole organ and systems levels. Glucocorticoids, therefore, activate many of the physiological systems that have little function in utero but are vital at birth to replace the respiratory, nutritive and excretory functions previously carried out by the placenta. However, by switching tissues from accretion to differentiation, early glucocorticoid overexposure in response to adverse conditions can programme fetal development with longer term physiological consequences for the adult offspring, which can extend to the next generation. The developmental effects of the glucocorticoids can be direct on fetal tissues with glucocorticoid receptors or mediated by changes in placental function or other endocrine systems. At the molecular level, glucocorticoids can act directly on gene transcription via their receptors or indirectly by epigenetic modifications of the genome. In this review, we examine the role and functional significance of glucocorticoids as regulatory signals during intrauterine development and discuss the mechanisms by which they act in utero to alter the developing epigenome and ensuing phenotype.
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Affiliation(s)
- Abigail L Fowden
- Centre for Trophoblast Research and Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3EG, UK
| | - Alison J Forhead
- Centre for Trophoblast Research and Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3EG, UK
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20
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Keller-Wood M, Feng X, Wood CE, Richards E, Anthony RV, Dahl GE, Tao S. Elevated maternal cortisol leads to relative maternal hyperglycemia and increased stillbirth in ovine pregnancy. Am J Physiol Regul Integr Comp Physiol 2014; 307:R405-13. [PMID: 24920731 DOI: 10.1152/ajpregu.00530.2013] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
In normal pregnancy, cortisol increases; however, further pathological increases in cortisol are associated with maternal and fetal morbidities. These experiments were designed to test the hypothesis that increased maternal cortisol would increase maternal glucose concentrations, suppress fetal growth, and impair neonatal glucose homeostasis. Ewes were infused with cortisol (1 mg·kg(-1)·day(-1)) from day 115 of gestation to term; maternal glucose, insulin, ovine placental lactogen, estrone, progesterone, nonesterified free fatty acids (NEFA), β-hydroxybutyrate (BHB), and electrolytes were measured. Infusion of cortisol increased maternal glucose concentration and slowed the glucose disappearance after injection of glucose; maternal infusion of cortisol also increased the incidence of fetal death at or near parturition. The design of the study was altered to terminate the study prior to delivery, and post hoc analysis of the data was performed to test the hypothesis that maternal metabolic factors predict the fetal outcome. In cortisol-infused ewes that had stillborn lambs, plasma insulin was increased relative to control ewes or cortisol-infused ewes with live lambs. Maternal cortisol infusion did not alter maternal food intake or plasma NEFA, BHB, estrone, progesterone or placental lactogen concentrations, and it did not alter fetal body weight, ponderal index, or fetal organ weights. Our study suggests that the adverse effect of elevated maternal cortisol on pregnancy outcome may be related to the effects of cortisol on maternal glucose homeostasis, and that chronic maternal stress or adrenal hypersecretion of cortisol may create fetal pathophysiology paralleling some aspects of maternal gestational diabetes.
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Affiliation(s)
- Maureen Keller-Wood
- Department of Pharmacodynamics, University of Florida, Gainesville, Florida;
| | - Xiaodi Feng
- Department of Pharmacodynamics, University of Florida, Gainesville, Florida
| | - Charles E Wood
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida
| | - Elaine Richards
- Department of Pharmacodynamics, University of Florida, Gainesville, Florida
| | - Russell V Anthony
- Department of Biomedical Sciences, College of Veterinary Medicine, Colorado State University, Fort Collins, Colorado
| | - Geoffrey E Dahl
- Department of Animal Sciences, University of Florida, Gainesville, Florida; and
| | - Sha Tao
- Department of Animal Sciences, University of Florida, Gainesville, Florida; and
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Richards EM, Wood CE, Rabaglino MB, Antolic A, Keller-Wood M. Mechanisms for the adverse effects of late gestational increases in maternal cortisol on the heart revealed by transcriptomic analyses of the fetal septum. Physiol Genomics 2014; 46:547-59. [PMID: 24867915 DOI: 10.1152/physiolgenomics.00009.2014] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
We have previously shown in sheep that 10 days of modest chronic increase in maternal cortisol resulting from maternal infusion of cortisol (1 mg/kg/day) caused fetal heart enlargement and Purkinje cell apoptosis. In subsequent studies we extended the cortisol infusion to term, finding a dramatic incidence of stillbirth in the pregnancies with chronically increased cortisol. To investigate effects of maternal cortisol on the heart, we performed transcriptomic analyses on the septa using ovine microarrays and Webgestalt and Cytoscape programs for pathway inference. Analyses of the transcriptomic effects of maternal cortisol infusion for 10 days (130 day cortisol vs 130 day control), or ∼25 days (140 day cortisol vs 140 day control) and of normal maturation (140 day control vs 130 day control) were performed. Gene ontology terms related to immune function and cytokine actions were significantly overrepresented as genes altered by both cortisol and maturation in the septa. After 10 days of cortisol, growth factor and muscle cell apoptosis pathways were significantly overrepresented, consistent with our previous histologic findings. In the term fetuses (∼25 days of cortisol) nutrient pathways were significantly overrepresented, consistent with altered metabolism and reduced mitochondria. Analysis of mitochondrial number by mitochondrial DNA expression confirmed a significant decrease in mitochondria. The metabolic pathways modeled as altered by cortisol treatment to term were different from those modeled during maturation of the heart to term, and thus changes in gene expression in these metabolic pathways may be indicative of the fetal heart pathophysiologies seen in pregnancies complicated by stillbirth, including gestational diabetes, Cushing's disease and chronic stress.
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Affiliation(s)
- Elaine M Richards
- Department of Pharmacodynamics, University of Florida, Gainesville, Florida; and
| | - Charles E Wood
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida
| | - Maria Belen Rabaglino
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida
| | - Andrew Antolic
- Department of Pharmacodynamics, University of Florida, Gainesville, Florida; and
| | - Maureen Keller-Wood
- Department of Pharmacodynamics, University of Florida, Gainesville, Florida; and
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Hemodynamic and metabolic correlates of perinatal white matter injury severity. PLoS One 2013; 8:e82940. [PMID: 24416093 PMCID: PMC3886849 DOI: 10.1371/journal.pone.0082940] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Accepted: 11/07/2013] [Indexed: 11/21/2022] Open
Abstract
Background and Purpose Although the spectrum of perinatal white matter injury (WMI) in preterm infants is shifting from cystic encephalomalacia to milder forms of WMI, the factors that contribute to this changing spectrum are unclear. We hypothesized that the variability in WMI quantified by immunohistochemical markers of inflammation could be correlated with the severity of impaired blood oxygen, glucose and lactate. Methods We employed a preterm fetal sheep model of in utero moderate hypoxemia and global severe but not complete cerebral ischemia that reproduces the spectrum of human WMI. Since there is small but measurable residual brain blood flow during occlusion, we sought to determine if the metabolic state of the residual arterial blood was associated with severity of WMI. Near the conclusion of hypoxia-ischemia, we recorded cephalic arterial blood pressure, blood oxygen, glucose and lactate levels. To define the spectrum of WMI, an ordinal WMI rating scale was compared against an unbiased quantitative image analysis protocol that provided continuous histo-pathological outcome measures for astrogliosis and microgliosis derived from the entire white matter. Results A spectrum of WMI was observed that ranged from diffuse non-necrotic lesions to more severe injury that comprised discrete foci of microscopic or macroscopic necrosis. Residual arterial pressure, oxygen content and blood glucose displayed a significant inverse association with WMI and lactate concentrations were directly related. Elevated glucose levels were the most significantly associated with less severe WMI. Conclusions Our results suggest that under conditions of hypoxemia and severe cephalic hypotension, WMI severity measured using unbiased immunohistochemical measurements correlated with several physiologic parameters, including glucose, which may be a useful marker of fetal response to hypoxia or provide protection against energy failure and more severe WMI.
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Gupta A, Srivastava S, Bhatnagar A. Cord blood thyroid stimulating hormone level — interpretation in light of perinatal factors. Indian Pediatr 2013; 51:32-6. [DOI: 10.1007/s13312-014-0330-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 08/21/2013] [Indexed: 11/24/2022]
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Glucocorticoids and preterm hypoxic-ischemic brain injury: the good and the bad. J Pregnancy 2012; 2012:751694. [PMID: 22970371 PMCID: PMC3431094 DOI: 10.1155/2012/751694] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Accepted: 07/13/2012] [Indexed: 12/20/2022] Open
Abstract
Fetuses at risk of premature delivery are now routinely exposed to maternal treatment with synthetic glucocorticoids. In randomized clinical trials, these substantially reduce acute neonatal systemic morbidity, and mortality, after premature birth and reduce intraventricular hemorrhage. However, the overall neurodevelopmental impact is surprisingly unclear; worryingly, postnatal glucocorticoids are consistently associated with impaired brain development. We review the clinical and experimental evidence on how glucocorticoids may affect the developing brain and highlight the need for systematic research.
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Salinas CE, Villena M, Blanco CE, Giussani DA. Adrenocortical suppression in highland chick embryos is restored during incubation at sea level. High Alt Med Biol 2011; 12:79-87. [PMID: 21452969 DOI: 10.1089/ham.2010.1040] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
By combining the chick embryo model with incubation at high altitude, this study tested the hypothesis that development at high altitude is related to a fetal origin of adrenocortical but not adrenomedullary suppression and that hypoxia is the mechanism underlying the relationship. Fertilized eggs from sea-level or high altitude hens were incubated at sea level or high altitude. Fertilized eggs from sea-level hens were also incubated at altitude with oxygen supplementation. At day 20 of incubation, embryonic blood was taken for measurement of plasma corticotropin, corticosterone, and Po(2). Following biometry, the adrenal glands were collected and frozen for measurement of catecholamine content. Development of chick embryos at high altitude led to pronounced adrenocortical blunting, but an increase in adrenal catecholamine content. These effects were similar whether the fertilized eggs were laid by sea-level or high altitude hens. The effects of high altitude on the stress axes were completely prevented by incubation at high altitude with oxygen supplementation. When chick embryos from high altitude hens were incubated at sea level, plasma hormones and adrenal catecholamine content were partially restored toward levels measured in sea-level chick embryos. There was a significant correlation between adrenocortical blunting and elevated adrenal catecholamine content with both asymmetric growth restriction and fetal hypoxia. The data support the hypothesis tested and provide evidence to isolate the direct contribution of developmental hypoxia to alterations in the stress system.
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Affiliation(s)
- Carlos E Salinas
- Instituto Boliviano de Biología de Altura, Facultad de Medicina, Universidad Mayor de San Andrés, La Paz, Bolivia
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Jellyman JK, Gardner DS, McGarrigle HH, Fowden AL, Giussani DA. Antenatal glucocorticoid therapy increases glucose delivery to cerebral circulations during acute hypoxemia in fetal sheep during late gestation. Am J Obstet Gynecol 2009; 201:82.e1-8. [PMID: 19371860 DOI: 10.1016/j.ajog.2009.01.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2008] [Revised: 11/25/2008] [Accepted: 01/13/2009] [Indexed: 11/17/2022]
Abstract
OBJECTIVE To determine the effects of 2 maternal injections with dexamethasone on the calculated oxygen and glucose deliveries to fetal cerebral and peripheral circulations during acute hypoxemia in sheep. STUDY DESIGN Beginning at 124 days, ewes received 2 intramuscular injections of either dexamethasone (2 x 12 mg, n = 10) or saline solution (2 x 2 mL, n = 12) 24 hours apart. Hypoxemia (1 hour) was induced 32 hours after the first injection (H1) and 3 days after the second (H2). RESULTS In saline solution-treated fetuses, glucose delivery was unchanged or increased in femoral and carotid circulations, respectively, during H1 and H2. In dexamethasone-treated fetuses, the increase in glucose delivery to the head tended to be greater during H1 and was significantly enhanced in dexamethasone- vs saline solution-treated fetuses during H2. CONCLUSION Two maternal injections with dexamethasone significantly enhanced glucose delivery to the head during acute hypoxemia in the ovine fetus.
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Affiliation(s)
- Juanita K Jellyman
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
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Wood CE. Fetal stress. Focus on "effects of acute acidemia on the fetal cardiovascular defense to acute hypoxemia" by Thakor and Giussani. Am J Physiol Regul Integr Comp Physiol 2008; 296:R88-9. [PMID: 19020289 DOI: 10.1152/ajpregu.90861.2008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Igosheva N, Taylor PD, Poston L, Glover V. Prenatal stress in the rat results in increased blood pressure responsiveness to stress and enhanced arterial reactivity to neuropeptide Y in adulthood. J Physiol 2007; 582:665-74. [PMID: 17495046 PMCID: PMC2075315 DOI: 10.1113/jphysiol.2007.130252] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
We have shown previously that stress in the pregnant rat leads to a heightened cardiovascular response to restraint in adult offspring. The present study was undertaken to explore further the persistent cardiovascular effects of prenatal stress, with a focus on peripheral vascular function. Sprague-Dawley female rats were exposed to restraint/bright light three times daily in the last week of pregnancy. Litters from stressed and control females were cross-fostered to control dams to eliminate possible effects of maternal stress on nursing behaviour. At 120 days, offspring cardiovascular variables were measured by radiotelemetry. Reactivity of mesenteric small arteries was assessed by myography, and responses to electrical field stimulation determined. Resting cardiovascular parameters in prenatally stressed (PS) offspring were similar to controls but PS rats showed a greater increase in systolic blood pressure following restraint stress (P<0.05). Recovery was also prolonged in PS animals compared with controls and was of longer duration in PS females than in PS males (P<0.05). Adult PS females, but not males, also had elevated basal plasma corticosterone levels in comparison with controls (P<0.05). Vascular reactivity to neuropeptide Y (P<0.05) and electrical field stimulation (P<0.05) in mesenteric arteries was also significantly increased in PS animals. Vascular responses to adrenergic agonists as well as endothelial dilator function did not differ between PS and controls. We conclude that prenatal stress during late gestation has long-lasting effects on cardiovascular responsiveness and vascular reactivity to neuropeptide Y in the offspring.
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Affiliation(s)
- Natalia Igosheva
- Maternal & Fetal Research Unit, Division of Reproduction and Endocrinology, King's College London, St. Thomas' Hospital, Lambeth Palace Road, London SE1 7EH, UK.
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Fletcher AJW, Gardner DS, Edwards CMB, Fowden AL, Giussani DA. Development of the ovine fetal cardiovascular defense to hypoxemia towards full term. Am J Physiol Heart Circ Physiol 2006; 291:H3023-34. [PMID: 16861695 DOI: 10.1152/ajpheart.00504.2006] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We tested the hypothesis that fetal cardiovascular responses to hypoxemia change close to full term in relation to the prepartum increase in fetal basal cortisol and investigated, in vivo, the neural and endocrine mechanisms underlying these changes. Fetal heart rate and peripheral hemodynamic responses to 1 h of hypoxemia were studied in 25 chronically instrumented sheep within three narrow gestational age ranges: 125–130 ( n = 13), 135–140 ( n = 6), and >140 ( n = 6) days (full term ∼145 days). Chemoreflex function and plasma concentrations of vasoconstrictor hormones were measured. Reductions in fetal arterial Po2 during hypoxemia were similar at all ages. At 125–130 days, hypoxemia elicited transient bradycardia, femoral vasoconstriction, and increases in plasma concentrations of catecholamines, neuropeptide Y (NPY), AVP, ACTH, and cortisol. Close to full term, in association with the prepartum increase in fetal basal cortisol, there was a developmental increase in the magnitude and persistence of fetal bradycardia and in the magnitude of the femoral constrictor response to hypoxemia. The mechanisms mediating these changes close to full term included increases in the gain of chemoreflex function and in the magnitudes of the fetal NPY and AVP responses to hypoxemia. Data combined irrespective of gestational age revealed significant correlations between fetal basal cortisol and fetal bradycardia, femoral resistance, chemoreflex function, and plasma AVP concentrations. The data show that the fetal cardiovascular defense to hypoxemia changes in pattern and magnitude just before full term because of alterations in the gain of the neural and endocrine mechanisms mediating them, in parallel with the prepartum increase in fetal basal cortisol.
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Affiliation(s)
- Andrew J W Fletcher
- Dept. of Physiology, Development & Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK
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O'Connor SJ, Ousey JC, Gardner DS, Fowden AL, Giussani DA. Development of baroreflex function and hind limb vascular reactivity in the horse fetus. J Physiol 2006; 572:155-64. [PMID: 16469779 PMCID: PMC1779647 DOI: 10.1113/jphysiol.2006.105635] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
This study investigated, in vivo, the mechanisms underlying the development of cardiovascular function in the horse fetus, with particular relevance to baroreflex function and hind limb vascular arterial reactivity to constrictor agonists. Under general anaesthesia, vascular catheters were inserted and a Transonic flow probe was implanted around one of the metatarsal arteries of 13 horse fetuses, either at 0.6 of gestation (n= 6) or at 0.9 of gestation (n= 7, term approximately 335 days). At least 5 days after surgery, pressor, vasoconstrictor and cardiac chronotropic responses to exogenous bolus doses of phenylephrine, angiotensin II and arginine vasopressin were recorded. Fetal cardiac baroreflex slopes were obtained using the peak pressor and heart rate responses to increasing doses of phenylephrine. Fetal treatment with phenylephrine, angiotensin II and vasopressin produced significant changes in arterial blood pressure, hind limb vascular resistance and heart rate. Pressor and vasopressor responses to all agonists were greater at 0.9 than at 0.6 of gestation; however, fetal cardiac baroreflex sensitivity decreased with advancing gestational age. Correlation analysis revealed that fetal plasma cortisol rather than gestational age was a greater determinant of pressor and vasopressor reactivity. In contrast, gestational age rather than cortisol better determined heart rate and baroreflex responsiveness in the equine fetus. The data show that development of cardiovascular function in the equine fetus occurs via cortisol-dependent and -independent pathways.
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Affiliation(s)
- Susie J O'Connor
- Department of Physiology, University of Cambridge, Cambridge CB2 3EG, UK.
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Sanhueza EM, Riquelme RA, Herrera EA, Giussani DA, Blanco CE, Hanson MA, Llanos AJ. Vasodilator tone in the llama fetus: the role of nitric oxide during normoxemia and hypoxemia. Am J Physiol Regul Integr Comp Physiol 2005; 289:R776-83. [PMID: 15905225 DOI: 10.1152/ajpregu.00071.2005] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The fetal llama responds to hypoxemia, with a marked peripheral vasoconstriction but, unlike the sheep, with little or no increase in cerebral blood flow. We tested the hypothesis that the role of nitric oxide (NO) may be increased during hypoxemia in this species, to counterbalance a strong vasoconstrictor effect. Ten fetal llamas were operated under general anesthesia. Mean arterial pressure (MAP), heart rate, cardiac output, total vascular resistance, blood flows, and vascular resistances in cerebral, carotid and femoral vascular beds were determined. Two groups were studied, one with nitric oxide synthase (NOS) blocker NG-nitro-l-arginine methyl ester (l-NAME), and the other with 0.9% NaCl (control group), during normoxemia, hypoxemia, and recovery. During normoxemia, l-NAME produced an increase in fetal MAP and a rapid bradycardia. Cerebral, carotid, and femoral vascular resistance increased and blood flow decreased to carotid and femoral beds, while cerebral blood flow did not change significantly. However, during hypoxemia cerebral and carotid vascular resistance fell by 44% from its value in normoxemia after l-NAME, although femoral vascular resistance progressively increased and remained high during recovery. We conclude that in the llama fetus: 1) NO has an important role in maintaining a vasodilator tone during both normoxemia and hypoxemia in cerebral and femoral vascular beds and 2) during hypoxemia, NOS blockade unmasked the action of other vasodilator agents that contribute, with nitric oxide, to preserving blood flow and oxygen delivery to the tissues.
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Affiliation(s)
- Emilia M Sanhueza
- Programa de Fisiopatología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Casilla 16038, Santiago 9, Chile.
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Wood CE, Chen GF, Keller-Wood M. Expression of nitric oxide synthase isoforms is reduced in late-gestation ovine fetal brainstem. Am J Physiol Regul Integr Comp Physiol 2005; 289:R613-R619. [PMID: 16014452 DOI: 10.1152/ajpregu.00722.2004] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Fetal baroreflex responsiveness increases in late gestation. An important modulator of baroreflex activity is the generation of nitric oxide in the brainstem nuclei that integrate afferent and efferent reflex activity. The present study was designed to test the hypothesis that nitric oxide synthase (NOS) isoforms are expressed in the fetal brainstem and that the expression of one or more of these enzymes is reduced in late gestation. Brainstem tissue was rapidly collected from fetal sheep of known gestational ages (80, 100, 120, 130, 145 days gestation and 1 day and 1 wk postnatal). Neuronal (nNOS), inducible (iNOS), and endothelial (eNOS) mRNA was measured using real-time PCR methodology specific for ovine NOS isoforms. The three enzymes were measured at the protein level using Western blot methodology. In tissue prepared for histology separately, the cellular pattern of immunostaining was identified in medullae from late-gestation fetal sheep. Fetal brainstem contained mRNA and protein of all three NOS isoforms, with nNOS the most abundant, followed by iNOS and eNOS, respectively. nNOS and iNOS mRNA abundances were highest at 80 days' gestation, with statistically significant decreases in abundance in more mature fetuses and postnatal animals. nNOS and eNOS protein abundance also decreased as a function of developmental age. nNOS and eNOS were expressed in neurons, iNOS was expressed in glia, and eNOS was expressed in vascular endothelial cells. We conclude that all three isoforms of NOS are constitutively expressed within the fetal brainstem, and the expression of all three forms is reduced with advancing gestation. We speculate that the reduced expression of NOS in this brain region plays a role in the increased fetal baroreflex activity in late gestation.
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Affiliation(s)
- Charles E Wood
- Dept. of Physiology and Functional Genomics, University of Florida College of Medicine, P.O. Box 100274, Gainesville, FL 32610-0274, USA.
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Jellyman JK, Gardner DS, Edwards CMB, Fowden AL, Giussani DA. Fetal cardiovascular, metabolic and endocrine responses to acute hypoxaemia during and following maternal treatment with dexamethasone in sheep. J Physiol 2005; 567:673-88. [PMID: 15975982 PMCID: PMC1474208 DOI: 10.1113/jphysiol.2005.089805] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
In sheep, direct fetal treatment with dexamethasone alters basal cardiovascular function and the cardiovascular response to acute hypoxaemia. However, in human clinical practice, dexamethasone is administered to the mother, not to the fetus. Hence, this study investigated physiological responses to acute hypoxaemia in fetal sheep during and following maternal treatment with dexamethasone in doses and at dose intervals used in human clinical practice. Under anaesthesia, 18 fetal sheep were instrumented with vascular and amniotic catheters, a carotid flow probe and a femoral flow probe at 118 days gestation (term ca 145 days). Following 6 days recovery at 124 days gestation, 10 ewes received dexamethasone (2 x 12 mg daily i.m. injections in saline). The remaining animals were saline-injected as age-matched controls. Two episodes of hypoxaemia (H) were induced in all animals by reducing the maternal F(IO2)for 1 h (H1, 8 h after the second injection; H2, 3 days after the second injection). In fetuses whose mothers received saline, hypoxaemia induced significant increases in fetal arterial blood pressure, carotid blood flow and carotid vascular conductance and femoral vascular resistance, significant falls in femoral blood flow and femoral vascular conductance and transient bradycardia. These cardiovascular responses were accompanied by a fall in arterial pH, increases in blood glucose and blood lactate concentrations and increased plasma concentrations of catecholamines. In fetuses whose mothers were treated with dexamethasone, bradycardia persisted throughout hypoxaemia, the magnitude of the femoral vasoconstriction, the glycaemic, lactacidaemic and acidaemic responses and the plasma concentration of neuropeptide Y (NPY) were all enhanced during H1. However, during H2, all of these physiological responses were similar to saline controls. In dexamethasone fetuses, the increase in plasma adrenaline was attenuated during H1 and the increase in carotid vascular conductance during hypoxaemia failed to reach statistical significance both during H1 and during H2. These data show that maternal treatment with dexamethasone in doses and intervals used in human obstetric practice modified the fetal cardiovascular, metabolic and endocrine defence responses to acute hypoxaemia. Furthermore, dexamethasone-induced alterations to these defences depended on whether the hypoxaemic challenge occurred during or following maternal dexamethasone treatment.
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Affiliation(s)
- J K Jellyman
- The Department of Physiology, University of Cambridge, Downing Street, Cambridge CB2 3EG, UK
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Quaedackers JS, Roelfsema V, Fraser M, Gunn AJ, Bennet L. Cardiovascular and endocrine effects of a single course of maternal dexamethasone treatment in preterm fetal sheep. BJOG 2005; 112:182-91. [PMID: 15663582 DOI: 10.1111/j.1471-0528.2004.00344.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To determine the effects of a single course of maternally administered dexamethasone on preterm fetal sheep in utero. DESIGN Prospective randomised controlled trial. SETTING University laboratory. SAMPLE Pregnant sheep at 0.7 of gestation. METHODS Pregnant ewes at 103 days of pregnancy (term = 147 days) were given two intramuscular injections of vehicle (n= 7) or 12 mg of dexamethasone (DEX; n= 8) 24 hours apart. Fetuses were continuously monitored for five days. MAIN OUTCOME MEASURES Fetal mean arterial blood pressure, carotid and femoral arterial blood flow and vascular resistance, heart rate, heart rate variability, fetal plasma cortisol and ACTH and fetal body movements. RESULTS DEX injections led to an acute increase in mean arterial blood pressure with a rise in carotid and femoral vascular resistance, a fall in femoral arterial blood flow, and a brief fall in fetal heart rate followed by significant tachycardia. From 24 hours after the injections, mean arterial blood pressure and vascular resistance returned to control values, however, a mild tachycardia [200 (3) vs 184 (4) bpm, P < 0.05] and loss of the circadian pattern of fetal heart rate variability persisted until the end of recording. Plasma ACTH and cortisol were markedly suppressed by DEX (P < 0.05), with values returning to control levels 32 and 72 hours after the first injection, respectively. There was no effect on basal fetal heart rate variability, body movements, carotid arterial blood flow, or the circadian pattern of fetal heart rate. CONCLUSION In contrast to previous experiments utilising direct fetal infusion of steroids, maternal administration of DEX was associated with only transient hypertension.
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Affiliation(s)
- Mark J M Nijland
- Department of Obstetrics and Gynecology, New York University School of Medicine, New York 10016, USA.
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