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Fowden AL, Vaughan OR, Murray AJ, Forhead AJ. Metabolic Consequences of Glucocorticoid Exposure before Birth. Nutrients 2022; 14:nu14112304. [PMID: 35684104 PMCID: PMC9182938 DOI: 10.3390/nu14112304] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 05/23/2022] [Accepted: 05/25/2022] [Indexed: 02/07/2023] Open
Abstract
Glucocorticoids have an important role in development of the metabolic phenotype in utero. They act as environmental and maturational signals in adapting feto-placental metabolism to maximize the chances of survival both before and at birth. They influence placental nutrient handling and fetal metabolic processes to support fetal growth, fuel storage and energy production with respect to nutrient availability. More specifically, they regulate the transport, utilization and production of a range of nutrients by the feto-placental tissues that enables greater metabolic flexibility in utero while minimizing any further drain on maternal resources during periods of stress. Near term, the natural rise in fetal glucocorticoid concentrations also stimulates key metabolic adaptations that prepare tissues for the new energy demanding functions after birth. Glucocorticoids, therefore, have a central role in the metabolic communication between the mother, placenta and fetus that optimizes offspring metabolic phenotype for survival to reproductive age. This review discusses the effects of maternal and fetal glucocorticoids on the supply and utilization of nutrients by the feto-placental tissues with particular emphasis on studies using quantitative methods to assess metabolism in rodents and sheep in vivo during late pregnancy. It considers the routes of glucocorticoid overexposure in utero, including experimental administration of synthetic glucocorticoids, and the mechanisms by which these hormones control feto-placental metabolism at the molecular, cellular and systems levels. It also briefly examines the consequences of intrauterine glucocorticoid overexposure for postnatal metabolic health and the generational inheritance of metabolic phenotype.
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Affiliation(s)
- Abigail L. Fowden
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK; (A.J.M.); (A.J.F.)
- Correspondence:
| | - Owen R. Vaughan
- EGA Institute for Women’s Health, University College London, London WC1E 6HX, UK;
| | - Andrew J. Murray
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK; (A.J.M.); (A.J.F.)
| | - Alison J. Forhead
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK; (A.J.M.); (A.J.F.)
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, UK
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2
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Hicks ZM, Beer HN, Herrera NJ, Gibbs RL, Lacey TA, Grijalva PC, Most MA, Yates DT. Hindlimb tissue composition shifts between the fetal and juvenile stages in the lamb. Transl Anim Sci 2021. [DOI: 10.1093/tas/txab164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Zena M Hicks
- Department of Animal Science, University of Nebraska – Lincoln, NE 68583, USA
| | - Haley N Beer
- Department of Animal Science, University of Nebraska – Lincoln, NE 68583, USA
| | - Nicolas J Herrera
- Department of Animal Science, University of Nebraska – Lincoln, NE 68583, USA
| | - Rachel L Gibbs
- Department of Animal Science, University of Nebraska – Lincoln, NE 68583, USA
| | - Taylor A Lacey
- Department of Animal Science, University of Nebraska – Lincoln, NE 68583, USA
| | - Pablo C Grijalva
- Department of Animal Science, University of Nebraska – Lincoln, NE 68583, USA
| | - Micah A Most
- Department of Animal Science, University of Nebraska – Lincoln, NE 68583, USA
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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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4
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Dall'asta A, Cagninelli G, Galli L, Frusca T, Ghi T. Monitoring fetal well-being in labor in late fetal growth restriction. Minerva Obstet Gynecol 2021; 73:453-461. [PMID: 33949824 DOI: 10.23736/s2724-606x.21.04819-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Late-onset fetal growth restriction (FGR) accounts for approximately 70-80% of all cases of FGR secondary to uteroplacental insufficiency. It is associated with an increased incidence of adverse antepartum and perinatal events, which in most instances result from hypoxic insults either present at the onset of labor or supervening during labor as a result of uterine contractions. Labor represents a stressful event for the fetoplacental unit being uterine contractions associated with an up-to 60% reduction of the uteroplacental perfusion. Intrapartum fetal heart rate monitoring by means of cardiotocography (CTG) currently represents the mainstay for the identification of fetal hypoxia during labor and is recommended for the fetal surveillance during labor in the case of FGR or other conditions associated with an increased risk of intrapartum hypoxia. In this review we discuss the potential implications of an impaired placental function on the intrapartum adaptation to the hypoxic stress and the role of the CTG and alternative techniques for the intrapartum monitoring of the fetal wellbeing in the context of FGR secondary to uteroplacental insufficiency.
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Affiliation(s)
- Andrea Dall'asta
- Unit of Obstetrics and Gynecology, Department of Medicine and Surgery, University of Parma, Parma, Italy - .,Department of Metabolism, Digestion and Reproduction, Institute of Reproductive and Developmental Biology, Imperial College London, London, UK -
| | - Greta Cagninelli
- Unit of Obstetrics and Gynecology, Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Letizia Galli
- Unit of Obstetrics and Gynecology, AUSL-IRCCS Reggio Emilia, Reggio Emilia, Italy
| | - Tiziana Frusca
- Unit of Obstetrics and Gynecology, Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Tullio Ghi
- Unit of Obstetrics and Gynecology, Department of Medicine and Surgery, University of Parma, Parma, Italy
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5
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Amberg BJ, DeKoninck PLJ, Kashyap AJ, Skinner SM, Rodgers KA, McGillick EV, Deprest JA, Hooper SB, Crossley KJ, Hodges RJ. Placental gas exchange during amniotic carbon dioxide insufflation in sheep. ULTRASOUND IN OBSTETRICS & GYNECOLOGY : THE OFFICIAL JOURNAL OF THE INTERNATIONAL SOCIETY OF ULTRASOUND IN OBSTETRICS AND GYNECOLOGY 2021; 57:305-313. [PMID: 31765050 DOI: 10.1002/uog.21933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 11/14/2019] [Accepted: 11/15/2019] [Indexed: 06/10/2023]
Abstract
OBJECTIVE Insufflation of the amniotic cavity with carbon dioxide (CO2 ) is used clinically to improve visibility during complex fetoscopic surgery. Insufflation with heated, humidified CO2 has recently been shown to reduce fetal hypercapnia and acidosis in sheep, compared with use of cold and dry CO2 , but the underlying mechanisms are unclear. The aim of this study was to investigate whether differences in placental CO2 and oxygen (O2 ) exchange during insufflation with heated and humidified vs cold and dry CO2 could explain these findings. METHODS Thirteen fetal lambs at 105 days of gestation (term, 146 days) were exteriorized partially, via a midline laparotomy and hysterotomy, and instrumented with an umbilical artery catheter, an umbilical vein catheter and a common umbilical vein flow probe. Arterial and venous catheters and flow probes were also inserted into the maternal uterine circulation. Six ewes were insufflated with cold, dry CO2 (22°C; 0-5% humidity) and seven with heated, humidified CO2 (40°C; 95-100% humidity) at 15 mmHg for 180 min. Blood-flow recordings and paired arterial and venous blood gases were sampled from uterine and umbilical vessels. Rates of placental CO2 and O2 exchange were calculated. RESULTS After 180 min of insufflation, fetal survival was 33% (2/6) using cold, dry CO2 and 71% (5/7) using heated, humidified CO2 . By 120 min, fetuses insufflated with heated, humidified CO2 had lower arterial CO2 levels and higher arterial pH compared to those insufflated with cold, dry gas. Insufflation decreased significantly placental gas exchange in both groups, as measured by rates of both (i) fetal CO2 clearance and O2 uptake and (ii) maternal O2 delivery and CO2 uptake from the fetal compartment. CONCLUSIONS Lower arterial CO2 and higher pH levels in fetuses insufflated with heated and humidified, compared to cold and dry, CO2 could not be explained by differences in placental gas exchange. Instead, heated and humidified insufflation appeared to reduce fetal CO2 absorption from the uterus, supporting its use in preference to cold, dry CO2 . © 2019 International Society of Ultrasound in Obstetrics and Gynecology.
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Affiliation(s)
- B J Amberg
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria, Australia
| | - P L J DeKoninck
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria, Australia
- Department of Obstetrics and Gynaecology, Erasmus MC-Sophia Children's Hospital, Rotterdam, The Netherlands
| | - A J Kashyap
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria, Australia
| | - S M Skinner
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia
| | - K A Rodgers
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia
| | - E V McGillick
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria, Australia
| | - J A Deprest
- Department of Obstetrics and Gynaecology, Division Woman and Child, University Hospitals Leuven, Leuven, Belgium
- Department of Development and Regeneration, Cluster Organ Systems, Faculty of Medicine, KU Leuven, Leuven, Belgium
| | - S B Hooper
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria, Australia
| | - K J Crossley
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria, Australia
| | - R J Hodges
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria, Australia
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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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7
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Skeffington KL, Beck C, Itani N, Niu Y, Shaw CJ, Giussani DA. Hypertension Programmed in Adult Hens by Isolated Effects of Developmental Hypoxia In Ovo. Hypertension 2020; 76:533-544. [PMID: 32536277 PMCID: PMC7340221 DOI: 10.1161/hypertensionaha.120.15045] [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: 02/02/2023]
Abstract
In mammals, pregnancy complicated by chronic hypoxia can program hypertension in the adult offspring. However, mechanisms remain uncertain because the partial contributions of the challenge on the placenta, mother, and fetus are difficult to disentangle. Here, we used chronic hypoxia in the chicken embryo-an established model system that permits isolation of the direct effects of developmental hypoxia on the cardiovascular system of the offspring, independent of additional effects on the mother or the placenta. Fertilized chicken eggs were exposed to normoxia (N; 21% O2) or hypoxia (H; 13.5%-14% O2) from the start of incubation (day 0) until day 19 (hatching, ≈day 21). Following hatching, all birds were maintained under normoxic conditions until ≈6 months of adulthood. Hypoxic incubation increased hematocrit (+27%) in the chicken embryo and induced asymmetrical growth restriction (body weight, -8.6%; biparietal diameter/body weight ratio, +7.5%) in the hatchlings (all P<0.05). At adulthood (181±4 days), chickens from hypoxic incubations remained smaller (body weight, -7.5%) and showed reduced basal and stimulated in vivo NO bioavailability (pressor response to NG-nitro-L-arginine methyl ester, -43%; phenylephrine pressor response during NO blockade, -61%) with significant hypertension (mean arterial blood pressure, +18%), increased cardiac work (ejection fraction, +12%; fractional shortening, +25%; enhanced baroreflex gain, +456%), and left ventricular wall thickening (left ventricular wall volume, +36%; all P<0.05). Therefore, we show that chronic hypoxia can act directly on a developing embryo to program hypertension, cardiovascular dysfunction, and cardiac wall remodeling in adulthood in the absence of any maternal or placental effects.
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Affiliation(s)
- Katie L. Skeffington
- From the Department of Physiology, Development and Neuroscience, University of Cambridge, United Kingdom (K.L.S., C.B., N.I., Y.N., C.J.S., D.A.G.)
| | - Christian Beck
- From the Department of Physiology, Development and Neuroscience, University of Cambridge, United Kingdom (K.L.S., C.B., N.I., Y.N., C.J.S., D.A.G.)
| | - Nozomi Itani
- From the Department of Physiology, Development and Neuroscience, University of Cambridge, United Kingdom (K.L.S., C.B., N.I., Y.N., C.J.S., D.A.G.)
| | - Youguo Niu
- From the Department of Physiology, Development and Neuroscience, University of Cambridge, United Kingdom (K.L.S., C.B., N.I., Y.N., C.J.S., D.A.G.)
| | - Caroline J. Shaw
- From the Department of Physiology, Development and Neuroscience, University of Cambridge, United Kingdom (K.L.S., C.B., N.I., Y.N., C.J.S., D.A.G.),Department of Metabolism, Digestion and Reproduction, Institute of Reproductive and Developmental Biology, Imperial College London, United Kingdom (C.J.S.)
| | - Dino A. Giussani
- From the Department of Physiology, Development and Neuroscience, University of Cambridge, United Kingdom (K.L.S., C.B., N.I., Y.N., C.J.S., D.A.G.)
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8
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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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9
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Almendros I, Martínez-Ros P, Farré N, Rubio-Zaragoza M, Torres M, Gutiérrez-Bautista ÁJ, Carrillo-Poveda JM, Sopena-Juncosa JJ, Gozal D, Gonzalez-Bulnes A, Farré R. Placental oxygen transfer reduces hypoxia-reoxygenation swings in fetal blood in a sheep model of gestational sleep apnea. J Appl Physiol (1985) 2019; 127:745-752. [PMID: 31369330 DOI: 10.1152/japplphysiol.00303.2019] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Obstructive sleep apnea (OSA), characterized by events of hypoxia-reoxygenation, is highly prevalent in pregnancy, negatively affecting the gestation process and particularly the fetus. Whether the consequences of OSA for the fetus and offspring are mainly caused by systemic alterations in the mother or by a direct effect of intermittent hypoxia in the fetus is unknown. In fact, how apnea-induced hypoxemic swings in OSA are transmitted across the placenta remains to be investigated. The aim of this study was to test the hypothesis, based on a theoretical background on the damping effect of oxygen transfer in the placenta, that oxygen partial pressure (Po2) swings resulting from obstructive apneas mimicking OSA are mitigated in the fetal circulation. To this end, four anesthetized ewes close to term pregnancy were subjected to obstructive apneas consisting of 25-s airway obstructions. Real-time Po2 was measured in the maternal carotid artery and in the umbilical vein with fast-response fiber-optic oxygen sensors. The amplitudes of Po2 swings in the umbilical vein were considerably smaller [3.1 ± 1.0 vs. 21.0 ± 6.1 mmHg (mean ± SE); P < 0.05]. Corresponding estimated swings in fetal and maternal oxyhemoglobin saturation tracked Po2 swings. This study provides novel insights into fetal oxygenation in a model of gestational OSA and highlights the importance of further understanding the impact of sleep-disordered breathing on fetal and offspring development.NEW & NOTEWORTHY This study in an airway obstruction sheep model of gestational sleep apnea provides novel data on how swings in oxygen partial pressure (Po2) translate from maternal to fetal blood. Real-time simultaneous measurement of Po2 in maternal artery and in umbilical vein shows that placenta transfer attenuates the magnitude of oxygenation swings. These data prompt further investigation of the extent to which maternal apneas could induce similar direct oxidative stress in fetal and maternal tissues.
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Affiliation(s)
- Isaac Almendros
- Unitat de Biofísica i Bioenginyeria, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain.,CIBER de Enfermedades Respiratorias, Madrid, Spain.,Institut d'Investigacions Biomediques August Pi Sunyer, Barcelona, Spain
| | - Paula Martínez-Ros
- Animal Production and Health Department, Veterinary Faculty, Universidad Cardenal Herrera-CEU Universities, Valencia, Spain
| | - Nuria Farré
- Department of Cardiology, Hospital del Mar, Barcelona, Spain.,Heart Diseases Biomedical Research Group, Hospital del Mar Medical Research Institute, Barcelona, Spain.,Department of Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Mónica Rubio-Zaragoza
- Bioregenerative Medicine and Applied Surgery Research Group, Animal Medicine and Surgery Department, Veterinary Faculty, Universidad Cardenal Herrera-CEU Universities, Valencia, Spain.,García Cugat Foundation for Biomedical Research, Barcelona, Spain
| | - Marta Torres
- CIBER de Enfermedades Respiratorias, Madrid, Spain.,Servei de Pneumologia, Hospital Clínic, Barcelona, Spain
| | - Álvaro J Gutiérrez-Bautista
- Anaesthesia Unit, Veterinary Teaching Hospital, Animal Medicine and Surgery Department, Veterinary Faculty, Universidad Cardenal Herrera-CEU Universities, Valencia, Spain
| | - José M Carrillo-Poveda
- Bioregenerative Medicine and Applied Surgery Research Group, Animal Medicine and Surgery Department, Veterinary Faculty, Universidad Cardenal Herrera-CEU Universities, Valencia, Spain.,García Cugat Foundation for Biomedical Research, Barcelona, Spain
| | - Joaquín J Sopena-Juncosa
- Bioregenerative Medicine and Applied Surgery Research Group, Animal Medicine and Surgery Department, Veterinary Faculty, Universidad Cardenal Herrera-CEU Universities, Valencia, Spain.,García Cugat Foundation for Biomedical Research, Barcelona, Spain
| | - David Gozal
- Department of Child Health, University of Missouri School of Medicine, Columbia, Missouri
| | - Antonio Gonzalez-Bulnes
- Department of Animal Reproduction, Deputy Directorate General of Research and Technology-Spanish National Institute for Agricultural and Food Research and Technology, Madrid, Spain
| | - Ramon Farré
- Unitat de Biofísica i Bioenginyeria, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain.,CIBER de Enfermedades Respiratorias, Madrid, Spain.,Institut d'Investigacions Biomediques August Pi Sunyer, Barcelona, Spain
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10
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Rozance PJ, Zastoupil L, Wesolowski SR, Goldstrohm DA, Strahan B, Cree-Green M, Sheffield-Moore M, Meschia G, Hay WW, Wilkening RB, Brown LD. Skeletal muscle protein accretion rates and hindlimb growth are reduced in late gestation intrauterine growth-restricted fetal sheep. J Physiol 2017; 596:67-82. [PMID: 28940557 DOI: 10.1113/jp275230] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 09/12/2017] [Indexed: 12/29/2022] Open
Abstract
KEY POINTS Adults who were affected by intrauterine growth restriction (IUGR) suffer from reductions in muscle mass, which may contribute to insulin resistance and the development of diabetes. We demonstrate slower hindlimb linear growth and muscle protein synthesis rates that match the reduced hindlimb blood flow and oxygen consumption rates in IUGR fetal sheep. These adaptations resulted in hindlimb blood flow rates in IUGR that were similar to control fetuses on a weight-specific basis. Net hindlimb glucose uptake and lactate output rates were similar between groups, whereas amino acid uptake was significantly lower in IUGR fetal sheep. Among all fetuses, blood O2 saturation and plasma glucose, insulin and insulin-like growth factor-1 were positively associated and norepinephrine was negatively associated with hindlimb weight. These results further our understanding of the metabolic and hormonal adaptations to reduced oxygen and nutrient supply with placental insufficiency that develop to slow hindlimb growth and muscle protein accretion. ABSTRACT Reduced skeletal muscle mass in the fetus with intrauterine growth restriction (IUGR) persists into adulthood and may contribute to increased metabolic disease risk. To determine how placental insufficiency with reduced oxygen and nutrient supply to the fetus affects hindlimb blood flow, substrate uptake and protein accretion rates in skeletal muscle, late gestation control (CON) (n = 8) and IUGR (n = 13) fetal sheep were catheterized with aortic and femoral catheters and a flow transducer around the external iliac artery. Muscle protein kinetic rates were measured using isotopic tracers. Hindlimb weight, linear growth rate, muscle protein accretion rate and fractional synthetic rate were lower in IUGR compared to CON (P < 0.05). Absolute hindlimb blood flow was reduced in IUGR (IUGR: 32.9 ± 5.6 ml min-1 ; CON: 60.9 ± 6.5 ml min-1 ; P < 0.005), although flow normalized to hindlimb weight was similar between groups. Hindlimb oxygen consumption rate was lower in IUGR (IUGR: 10.4 ± 1.4 μmol min-1 100 g-1 ; CON: 14.7 ± 1.3 μmol min-1 100 g-1 ; P < 0.05). Hindlimb glucose uptake and lactate output rates were similar between groups, whereas amino acid uptake was lower in IUGR (IUGR: 1.3 ± 0.5 μmol min-1 100 g-1 ; CON: 2.9 ± 0.2 μmol min-1 100 g-1 ; P < 0.05). Blood O2 saturation (r2 = 0.80, P < 0.0001) and plasma glucose (r2 = 0.68, P < 0.0001), insulin (r2 = 0.40, P < 0.005) and insulin-like growth factor (IGF)-1 (r2 = 0.80, P < 0.0001) were positively associated and norepinephrine (r2 = 0.59, P < 0.0001) was negatively associated with hindlimb weight. Slower hindlimb linear growth and muscle protein synthesis rates match reduced hindlimb blood flow and oxygen consumption rates in the IUGR fetus. Metabolic adaptations to slow hindlimb growth are probably hormonally-mediated by mechanisms that include increased fetal norepinephrine and reduced IGF-1 and insulin.
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Affiliation(s)
- Paul J Rozance
- Department of Pediatrics, University of Colorado School of Medicine, Perinatal Research Center, Aurora, CO, USA
| | - Laura Zastoupil
- Department of Pediatrics, University of Colorado School of Medicine, Perinatal Research Center, Aurora, CO, USA
| | - Stephanie R Wesolowski
- Department of Pediatrics, University of Colorado School of Medicine, Perinatal Research Center, Aurora, CO, USA
| | - David A Goldstrohm
- Department of Pediatrics, University of Colorado School of Medicine, Perinatal Research Center, Aurora, CO, USA
| | - Brittany Strahan
- Department of Pediatrics, University of Colorado School of Medicine, Perinatal Research Center, Aurora, CO, USA
| | - Melanie Cree-Green
- Department of Pediatrics, University of Colorado School of Medicine, Perinatal Research Center, Aurora, CO, USA
| | - Melinda Sheffield-Moore
- Department of Internal Medicine, University of Texas Medical Branch, Division of Endocrinology, Galveston, TX, USA
| | - Giacomo Meschia
- Department of Pediatrics, University of Colorado School of Medicine, Perinatal Research Center, Aurora, CO, USA
| | - William W Hay
- Department of Pediatrics, University of Colorado School of Medicine, Perinatal Research Center, Aurora, CO, USA
| | - Randall B Wilkening
- Department of Pediatrics, University of Colorado School of Medicine, Perinatal Research Center, Aurora, CO, USA
| | - Laura D Brown
- Department of Pediatrics, University of Colorado School of Medicine, Perinatal Research Center, Aurora, CO, USA
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11
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Soto SM, Blake AC, Wesolowski SR, Rozance PJ, Barthel KB, Gao B, Hetrick B, McCurdy CE, Garza NG, Hay WW, Leinwand LA, Friedman JE, Brown LD. Myoblast replication is reduced in the IUGR fetus despite maintained proliferative capacity in vitro. J Endocrinol 2017; 232:475-491. [PMID: 28053000 PMCID: PMC5440081 DOI: 10.1530/joe-16-0123] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 01/04/2017] [Indexed: 02/04/2023]
Abstract
Adults who were affected by intrauterine growth restriction (IUGR) suffer from reductions in muscle mass and insulin resistance, suggesting muscle growth may be restricted by molecular events that occur during fetal development. To explore the basis of restricted fetal muscle growth, we used a sheep model of progressive placental insufficiency-induced IUGR to assess myoblast proliferation within intact skeletal muscle in vivo and isolated myoblasts stimulated with insulin in vitro Gastrocnemius and soleus muscle weights were reduced by 25% in IUGR fetuses compared to those in controls (CON). The ratio of PAX7+ nuclei (a marker of myoblasts) to total nuclei was maintained in IUGR muscle compared to CON, but the fraction of PAX7+ myoblasts that also expressed Ki-67 (a marker of cellular proliferation) was reduced by 23%. Despite reduced proliferation in vivo, fetal myoblasts isolated from IUGR biceps femoris and cultured in enriched media in vitro responded robustly to insulin in a dose- and time-dependent manner to increase proliferation. Similarly, insulin stimulation of IUGR myoblasts upregulated key cell cycle genes and DNA replication. There were no differences in the expression of myogenic regulatory transcription factors that drive commitment to muscle differentiation between CON and IUGR groups. These results demonstrate that the molecular machinery necessary for transcriptional control of proliferation remains intact in IUGR fetal myoblasts, indicating that in vivo factors such as reduced insulin and IGF1, hypoxia and/or elevated counter-regulatory hormones may be inhibiting muscle growth in IUGR fetuses.
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Affiliation(s)
- Susan M Soto
- Department of PediatricsUniversity of Colorado School of Medicine, Perinatal Research Center, Aurora, Colorado, USA
| | - Amy C Blake
- Department of PediatricsUniversity of Colorado School of Medicine, Perinatal Research Center, Aurora, Colorado, USA
| | - Stephanie R Wesolowski
- Department of PediatricsUniversity of Colorado School of Medicine, Perinatal Research Center, Aurora, Colorado, USA
| | - Paul J Rozance
- Department of PediatricsUniversity of Colorado School of Medicine, Perinatal Research Center, Aurora, Colorado, USA
| | - Kristen B Barthel
- Department of MolecularCellular, and Developmental Biology, University of Colorado Boulder, BioFrontiers Institute, Boulder, Colorado, USA
| | - Bifeng Gao
- Department of MedicineUniversity of Colorado School of Medicine, Aurora, Colorado, USA
| | - Byron Hetrick
- Department of Human PhysiologyUniversity of Oregon, Eugene, Oregon, USA
| | - Carrie E McCurdy
- Department of Human PhysiologyUniversity of Oregon, Eugene, Oregon, USA
| | - Natalia G Garza
- Department of PediatricsUniversity of Colorado School of Medicine, Perinatal Research Center, Aurora, Colorado, USA
| | - William W Hay
- Department of PediatricsUniversity of Colorado School of Medicine, Perinatal Research Center, Aurora, Colorado, USA
| | - Leslie A Leinwand
- Department of MolecularCellular, and Developmental Biology, University of Colorado Boulder, BioFrontiers Institute, Boulder, Colorado, USA
| | - Jacob E Friedman
- Department of PediatricsUniversity of Colorado School of Medicine, Perinatal Research Center, Aurora, Colorado, USA
| | - Laura D Brown
- Department of PediatricsUniversity of Colorado School of Medicine, Perinatal Research Center, Aurora, Colorado, USA
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12
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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: 228] [Impact Index Per Article: 28.5] [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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13
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14
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Thakor AS, Giussani DA. Effects of acute acidemia on the fetal cardiovascular defense to acute hypoxemia. Am J Physiol Regul Integr Comp Physiol 2008; 296:R90-9. [PMID: 18922958 DOI: 10.1152/ajpregu.90689.2008] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In complicated pregnancy, fetal hypoxemia rarely occurs in isolation but is often accompanied by fetal acidemia. There is growing clinical concern about the combined effects of fetal hypoxemia and fetal acidemia on neonatal outcome. However, the effects on the fetal defense responses to acute hypoxemia during fetal acidemia are not well understood. This study tested the hypothesis that fetal acidemia affects the fetal defense responses to acute hypoxemia. The hypothesis was tested by investigating, in the late-gestation sheep fetus surgically prepared for long-term recording, the in vivo effects of acute fetal acidemia on 1) the fetal cardiovascular responses to acute hypoxemia and 2) the neural and endocrine mechanisms mediating these responses. Under general anesthesia, five sheep fetuses at 0.8 gestation were instrumented with catheters and Transonic flow probes around the femoral and umbilical arteries. After 5 days, animals were subjected to an acute hypoxemia protocol during intravenous infusion of saline or treatment with acidified saline. Treatment with acidified saline reduced fetal basal pH from 7.35 +/- 0.01 to 7.29 +/- 0.01 but did not alter basal cardiovascular variables, blood glucose, or plasma concentrations of catecholamines, ACTH, and cortisol. During hypoxemia, treatment with acidified saline increased the magnitude of the fetal bradycardia and femoral vasoconstriction and concomitantly increased chemoreflex function and enhanced the increments in plasma concentrations of catecholamines, ACTH, and cortisol. Acidemia also reversed the increase in umbilical vascular conductance during hypoxemia to vasoconstriction. In conclusion, the data support our hypothesis and show that acute acidemia markedly alters fetal hemodynamic, metabolic, and endocrine responses to acute hypoxemia.
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Affiliation(s)
- A S Thakor
- Dept. of Physiology, Development & Neuroscience, Univ. of Cambridge, Cambridge CB2 3EG, UK
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15
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Thakor AS, Bloomfield MR, Patterson M, Giussani DA. Calcitonin gene-related peptide antagonism attenuates the haemodynamic and glycaemic responses to acute hypoxaemia in the late gestation sheep fetus. J Physiol 2005; 566:587-97. [PMID: 15860534 PMCID: PMC1464744 DOI: 10.1113/jphysiol.2005.085431] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2005] [Accepted: 04/27/2005] [Indexed: 12/14/2022] Open
Abstract
The fetal defence to acute hypoxaemia involves cardiovascular and metabolic responses, which include peripheral vasoconstriction and hyperglycaemia. Both these responses are mediated via neuroendocrine mechanisms, which require the stimulation of the sympathetic nervous system. In the adult, accumulating evidence supports a role for calcitonin gene-related peptide (CGRP) in the activation of sympathetic outflow. However, the role of CGRP in stimulated cardiovascular and metabolic functions before birth is completely unknown. This study tested the hypothesis that CGRP plays a role in the fetal cardiovascular and metabolic defence responses to acute hypoxaemia by affecting sympathetic outflow. Under anaesthesia, five sheep fetuses at 0.8 of gestation were surgically instrumented with catheters and a femoral arterial Transonic flow-probe. Five days later, fetuses were subjected to 0.5 h hypoxaemia during either i.v. saline or a selective CGRP antagonist in randomised order. Treatment started 30 min before hypoxaemia and ran continuously until the end of the challenge. Arterial samples were taken for blood gases, metabolic status and hormone analyses. CGRP antagonism did not alter basal arterial blood gas, metabolic, cardiovascular or endocrine status. During hypoxaemia, similar falls in Pa,O2 occurred in all fetuses. During saline infusion, hypoxaemia induced hypertension, bradycardia, femoral vasoconstriction, hyperglycaemia and an increase in haemoglobin, catecholamines and neuropeptide Y (NPY). In contrast, CGRP antagonism markedly diminished the femoral vasoconstrictor and glycaemic responses to hypoxaemia, and attenuated the increases in haemoglobin, catecholamines and NPY. Combined, these results strongly support the hypothesis that CGRP plays a role in the fetal cardiovascular and metabolic defence to hypoxaemia by affecting sympathetic outflow.
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Affiliation(s)
- A S Thakor
- Department of Physiology, University of Cambridge, Downing Street, Cambridge CB2 3EG, UK
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16
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Armitage JA, Khan IY, Taylor PD, Nathanielsz PW, Poston L. Developmental programming of the metabolic syndrome by maternal nutritional imbalance: how strong is the evidence from experimental models in mammals? J Physiol 2004; 561:355-77. [PMID: 15459241 PMCID: PMC1665360 DOI: 10.1113/jphysiol.2004.072009] [Citation(s) in RCA: 429] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2004] [Accepted: 09/28/2004] [Indexed: 12/24/2022] Open
Abstract
The incidence of the metabolic syndrome, a cluster of abnormalities focusing on insulin resistance and associated with high risk for cardiovascular disease and diabetes, is reaching epidemic proportions. Prevalent in both developed and developing countries, the metabolic syndrome has largely been attributed to altered dietary and lifestyle factors that favour the development of central obesity. However, population-based studies have suggested that predisposition to the metabolic syndrome may be acquired very early in development through inappropriate fetal or neonatal nutrition. Further evidence for developmental programming of the metabolic syndrome has now been suggested by animal studies in which the fetal environment has been manipulated through altered maternal dietary intake or modification of uterine artery blood flow. This review examines these studies and assesses whether the metabolic syndrome can be reliably induced by the interventions made. The validity of the different species, diets, feeding regimes and end-point measures used is also discussed.
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Affiliation(s)
- James A Armitage
- Maternal and Fetal Research Unit, Department of Women's Health, Guy's, King's and St Thomas' School of Medicine, King's College London, UK.
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17
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Abstract
The aim of this paper is to review the mechanisms by which animal and human fetuses survive prolonged periods of substrate deprivation in utero. Two reasons why such information is important for those who care for growth-restricted fetuses and neonates are as follows. (1) Understanding the physiology is central to designing appropriate tests for determining fetal well-being. For instance, most currently available techniques for monitoring fetal well-being are actually better designed to detect acute than chronic fetal hypoxaemia. (2) There is increasing interest in the medium- and long-term consequences of fetal growth restriction on cardiovascular, neurological and lung function. As an example, the reasons why chronic oxygen deprivation may influence cerebral structure and function are discussed.
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Affiliation(s)
- Donald M Peebles
- Department of Obstetrics and Gynaecology, University College London, 86-96 Chenies Mews, London WC1E 6HX, UK.
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18
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Li X, Tang D, Zhou S, Zhou G, Wang C, Zhuang Y, Wu G, Shen L. Redistribution of power spectrum of heart rate variability during acute umbilical artery embolism and hypoxemia in late-gestation fetal sheep. Eur J Obstet Gynecol Reprod Biol 2004; 114:137-43. [PMID: 15140505 DOI: 10.1016/j.ejogrb.2003.10.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2003] [Revised: 08/04/2003] [Accepted: 10/08/2003] [Indexed: 11/28/2022]
Abstract
OBJECTS Fetal heart rate variability (HRV) is subject to a number of factors, including fetal distress. The aim of this study was to investigate the power spectral distribution of fetal heart rate variability during acute hypoxemia following umbilical artery embolism and to test the hypothesis that the relative proportion of frequency domains in total power of HRV, reflects the changes in HRV during hypoxemia more closely than the absolute values. METHODS Acute hypoxemia was induced in seven catheterized late-gestation fetal sheep by repeated injections of microspheres to cause umbilical artery embolism. The very-low, low-, middle- and high-frequency domains (0-0.025, 0.025-0.125, 0.125-0.20, and 0.20-0.50 cycles/beat, respectively) were determined by power spectral analysis. RESULTS Umbilical artery embolism induced marked fetal hypoxemia, hypercapnia and acidosis, accompanied by an increase in heart rate and a decrease in arterial blood pressure. These changes were associated with the increase in power over the entire frequency range and in the relative power in the low-frequency range (P<0.01), and with decrease in the relative power in the high-frequency range (P<0.05). Correlations were found between the relative power in the low- and high-frequency ranges and PO2 and between the relative power in these ranges and mean arterial blood pressure (P<0.05), but not PCO2 or pH. CONCLUSIONS The present study indicates that acute hypoxemia induced by umbilical artery embolism leads to the redistribution of power spectral density of fetal HRV and that the relative proportion of individual frequency domains may reflect the changes in HRV during acute hypoxemia more closely than the absolute power values.
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Affiliation(s)
- Xiaotian Li
- The Obstetrics & Gynecology Hospital, Fudan University, 419 Fangxie Road, Shanghai 200011, China.
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