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Brombach C, Tong W, Giussani DA. Maternal obesity: new placental paradigms unfolded. Trends Mol Med 2022; 28:823-835. [PMID: 35760668 DOI: 10.1016/j.molmed.2022.05.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 05/27/2022] [Accepted: 05/31/2022] [Indexed: 01/24/2023]
Abstract
The prevalence of maternal obesity is increasing at an alarming rate, and is providing a major challenge for obstetric practice. Adverse effects on maternal and fetal health are mediated by complex interactions between metabolic, inflammatory, and oxidative stress signaling in the placenta. Endoplasmic reticulum (ER) stress and activation of the unfolded protein response (UPR) are common downstream pathways of cell stress, and there is evidence that this conserved homeostatic response may be a key mediator in the pathogenesis of placental dysfunction. We summarize the current literature on the placental cellular and molecular changes that occur in obese women. A special focus is cast onto placental ER stress in obese pregnancy, which may provide a novel link for future investigation.
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Affiliation(s)
| | - Wen Tong
- Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge CB2 3EL, UK; Centre for Trophoblast Research, University of Cambridge, Cambridge CB2 3EG, UK; Cambridge Strategic Research Initiative in Reproduction, Cambridge CB2 3EL, Cambridge UK.
| | - Dino A Giussani
- Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge CB2 3EL, UK; Centre for Trophoblast Research, University of Cambridge, Cambridge CB2 3EG, UK; Cambridge Strategic Research Initiative in Reproduction, Cambridge CB2 3EL, Cambridge UK; Cambridge Cardiovascular Centre for Research Excellence, Cambridge CB2 0QQ, UK.
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2
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King VJ, Bennet L, Stone PR, Clark A, Gunn AJ, Dhillon SK. Fetal growth restriction and stillbirth: Biomarkers for identifying at risk fetuses. Front Physiol 2022; 13:959750. [PMID: 36060697 PMCID: PMC9437293 DOI: 10.3389/fphys.2022.959750] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 07/29/2022] [Indexed: 11/13/2022] Open
Abstract
Fetal growth restriction (FGR) is a major cause of stillbirth, prematurity and impaired neurodevelopment. Its etiology is multifactorial, but many cases are related to impaired placental development and dysfunction, with reduced nutrient and oxygen supply. The fetus has a remarkable ability to respond to hypoxic challenges and mounts protective adaptations to match growth to reduced nutrient availability. However, with progressive placental dysfunction, chronic hypoxia may progress to a level where fetus can no longer adapt, or there may be superimposed acute hypoxic events. Improving detection and effective monitoring of progression is critical for the management of complicated pregnancies to balance the risk of worsening fetal oxygen deprivation in utero, against the consequences of iatrogenic preterm birth. Current surveillance modalities include frequent fetal Doppler ultrasound, and fetal heart rate monitoring. However, nearly half of FGR cases are not detected in utero, and conventional surveillance does not prevent a high proportion of stillbirths. We review diagnostic challenges and limitations in current screening and monitoring practices and discuss potential ways to better identify FGR, and, critically, to identify the “tipping point” when a chronically hypoxic fetus is at risk of progressive acidosis and stillbirth.
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Affiliation(s)
- Victoria J. King
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Laura Bennet
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Peter R. Stone
- Department of Obstetrics and Gynaecology, The University of Auckland, Auckland, New Zealand
| | - Alys Clark
- Department of Obstetrics and Gynaecology, The University of Auckland, Auckland, New Zealand
- Auckland Biomedical Engineering Institute, The University of Auckland, Auckland, New Zealand
| | - Alistair J. Gunn
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Simerdeep K. Dhillon
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
- *Correspondence: Simerdeep K. Dhillon,
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3
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Camm EJ, Cross CM, Kane AD, Tarry-Adkins JL, Ozanne SE, Giussani DA. Maternal antioxidant treatment protects adult offspring against memory loss and hippocampal atrophy in a rodent model of developmental hypoxia. FASEB J 2021; 35:e21477. [PMID: 33891326 DOI: 10.1096/fj.202002557rr] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 02/11/2021] [Accepted: 02/11/2021] [Indexed: 02/02/2023]
Abstract
Chronic fetal hypoxia is one of the most common outcomes in complicated pregnancy in humans. Despite this, its effects on the long-term health of the brain in offspring are largely unknown. Here, we investigated in rats whether hypoxic pregnancy affects brain structure and function in the adult offspring and explored underlying mechanisms with maternal antioxidant intervention. Pregnant rats were randomly chosen for normoxic or hypoxic (13% oxygen) pregnancy with or without maternal supplementation with vitamin C in their drinking water. In one cohort, the placenta and fetal tissues were collected at the end of gestation. In another, dams were allowed to deliver naturally, and offspring were reared under normoxic conditions until 4 months of age (young adult). Between 3.5 and 4 months, the behavior, cognition and brains of the adult offspring were studied. We demonstrated that prenatal hypoxia reduced neuronal number, as well as vascular and synaptic density, in the hippocampus, significantly impairing memory function in the adult offspring. These adverse effects of prenatal hypoxia were independent of the hypoxic pregnancy inducing fetal growth restriction or elevations in maternal or fetal plasma glucocorticoid levels. Maternal vitamin C supplementation during hypoxic pregnancy protected against oxidative stress in the placenta and prevented the adverse effects of prenatal hypoxia on hippocampal atrophy and memory loss in the adult offspring. Therefore, these data provide a link between prenatal hypoxia, placental oxidative stress, and offspring brain health in later life, providing insight into mechanism and identifying a therapeutic strategy.
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Affiliation(s)
- Emily J Camm
- Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge, UK
| | - Christine M Cross
- Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge, UK
| | - Andrew D Kane
- Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge, UK
| | - Jane L Tarry-Adkins
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, UK
| | - Susan E Ozanne
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, UK.,Cambridge Strategic Initiative in Reproduction, Cambridge, UK
| | - Dino A Giussani
- Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge, UK.,Cambridge Strategic Initiative in Reproduction, Cambridge, UK
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4
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Contag S, Visentin S, Goetzinger K, Cosmi E. Use of the Renal Artery Doppler to Identify Small for Gestational Age Fetuses at Risk for Adverse Neonatal Outcomes. J Clin Med 2021; 10:jcm10091835. [PMID: 33922550 PMCID: PMC8122939 DOI: 10.3390/jcm10091835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 04/18/2021] [Accepted: 04/19/2021] [Indexed: 11/21/2022] Open
Abstract
Objective: To measure the sensitivity and positive predictive value (PPV) for an adverse neonatal outcome among growth-restricted fetuses (FGR) comparing the cerebral–placental ratio (CPR) with the cerebral–renal ratio (CRR). Methods: Retrospective analysis of 92 women who underwent prenatal ultrasound at the University of Maryland and the University of Padua. Renal, middle cerebral and umbilical artery Doppler waveforms were recorded for all scans during the third trimester. The last scan prior to delivery was included for analysis. We calculated the test characteristics of the pulsatility indices (PI) of the umbilical and renal arteries in addition to the derived CPR and CRR to detect a composite adverse neonatal outcome. Results: The test characteristics of the four Doppler ratios to detect increased risk for the composite neonatal outcome demonstrated that the umbilical artery pulsatility index had the best test performance (sensitivity 64% (95% CI: 47–82%), PPV 24% (95% CI: 21–27), and positive likelihood ratio 2.7 (95% CI: 1.4–5.2)). There was no benefit to using the CRR compared with the CPR. The agreement between tests was moderate to poor (Kappa value CPR compared with CRR: 0.5 (95%CI 0.4–0.70), renal artery PI:−0.1 (95% CI −0.2–0.0), umbilical artery PI: 0.5 (95% CI 0.4–0.7)). Only the umbilical artery had an area under the receiver operating curve that was significantly better compared with the CPR as a reference (p-value < 0.01). Conclusions: The data that we present do not support the use of renal artery Doppler as a useful clinical test to identify a fetus at risk for an adverse neonatal outcome. Within the various indices applied to this population, umbilical artery Doppler performed the best in identifying the fetuses at risk for an adverse perinatal outcome.
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Affiliation(s)
- Stephen Contag
- Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology and Women’s Health, University of Minnesota, Minneapolis, MN 55455, USA;
| | - Silvia Visentin
- Department of Women and Child Heath, University of Padua School of Medicine, 35122 Padova, Italy;
| | - Katherine Goetzinger
- Division of Maternal Fetal Medicine, Department of Obstetrics, Gynecology & Reproductive Sciences, University of Maryland School of Medicine, Baltimore, MD 21201, USA;
| | - Erich Cosmi
- Department of Women and Child Heath, University of Padua School of Medicine, 35122 Padova, Italy;
- Correspondence:
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5
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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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Shaw CJ, Botting KJ, Niu Y, Lees CC, Giussani DA. Maternal and fetal cardiovascular and metabolic effects of intra-operative uterine handling under general anesthesia during pregnancy in sheep. Sci Rep 2020; 10:10867. [PMID: 32616745 PMCID: PMC7331497 DOI: 10.1038/s41598-020-67714-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 06/05/2020] [Indexed: 11/25/2022] Open
Abstract
A cohort study of 6,500,000 human pregnancies showed an increased risk of adverse fetal outcomes following abdominal but not non-abdominal surgery under general anesthesia. This may be the consequence of uterine handling during abdominal surgery. However, there are no data on any effects on the cardiometabolic physiology of the fetus or mother in response to uterine manipulation in otherwise healthy pregnancy. Consequently, 9 sheep in late gestation were anesthetized with isofluorane and maternal and fetal catheters and flow probes were implanted to determine cardiovascular and metabolic changes during uterine handling. Uterine handling led to an acute increase in uterine artery vascular resistance, fetal peripheral vasoconstriction, a reduction in oxygen delivery to the femoral circulation, worsening fetal acidosis. There was no evidence of systemic fetal hypoxia, or changes in fetal heart rate, carotid blood flow or carotid oxygen delivery. Therefore, the data support that uterine handling during abdominal surgery under general anesthesia can impact adversely on fetal cardiometabolic health. This may provide a potential explanation linking adverse fetal outcomes in abdominal compared with non-abdominal surgery during pregnancy. The data have important implications for human fetal surgery where the uterus is handled, as operative procedures during late gestation under general maternal anesthesia become more prevalent.
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Affiliation(s)
- Caroline J Shaw
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3EG, UK.,Institute of Reproductive and Developmental Biology, Imperial College London, London, UK
| | - Kimberley J Botting
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3EG, UK.,Cambridge Cardiovascular Research Initiative, Cambridge, UK
| | - Youguo Niu
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3EG, UK.,Cambridge Cardiovascular Research Initiative, Cambridge, UK
| | - Christoph C Lees
- Institute of Reproductive and Developmental Biology, Imperial College London, London, UK.,Department of Obstetrics and Gynecology, University Hospitals Leuven, Leuven, Belgium
| | - Dino A Giussani
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3EG, UK. .,Cambridge Cardiovascular Research Initiative, Cambridge, UK.
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7
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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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8
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Contag S, Patel P, Payton S, Crimmins S, Goetzinger KR. Renal artery Doppler compared with the cerebral placental ratio to identify fetuses at risk for adverse neonatal outcome. J Matern Fetal Neonatal Med 2019; 34:532-540. [PMID: 31060397 DOI: 10.1080/14767058.2019.1610735] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Background: Current clinical practice incorporates an umbilical artery resistance index or a ratio of the middle cerebral artery (MCA PI) to the umbilical artery pulsatility index (UA PI) known as the cerebral placental ratio (CPR) to assess wellbeing in the small for gestational age fetus. Previous reports using the renal artery Doppler indices have not been consistent in regards to their design and clinical use. Our objective is to develop reference values for renal artery Doppler indices and validate their use compared with the UA PI or CPR to identify fetuses that will develop a composite neonatal outcome.Methods: We performed 9700 ultrasounds among 2852 women at 20-40 weeks of gestation at the University of Maryland between 1 June 2016 and 1 December 2016. Nomograms were first developed using one randomly selected scan from each of a subgroup of 860 women without any comorbidities. The nomograms were validated among a cohort of 550 women who subsequently delivered at the University of Maryland Medical Center. We compared the area under the receiver operating characteristic curve (AUROC) between the CPR and UA PI, and the renal artery Doppler parameters (renal artery pulsatility index (RA PI), systolic diastolic ratio (RA SDR), and peak systolic velocity (RA PSV)). The primary outcome was the development any one of the composite neonatal outcome components (death, intensive care unit admission, ventilator for more than 6 h, hypoxic ischemic encephalopathy or necrotizing enterocolitis) or admission to the neonatal intensive care unit (NICU) for any indication.Results: The renal artery Doppler indices did not improve identification of fetuses that would subsequently develop one of the components of the composite neonatal outcome (AUROC for CPR 0.54, 95% CI (0.49-0.59), versus the UA PI: 0.59 (0.54-0.64) p = .07, the RA PI: 0.51 (0.48-0.55) p = .41, RA SDR 0.54 (0.49-0.58) p = .99, or RA PSV 0.51 (0.47-0.55) p = .37). There was no difference when comparing AUROC to detect NICU admission (AUROC for CPR 0.53, 95% CI (0.49-0.58), versus the UA PI: 0.57 (0.52-0.62) p = .14, the RA PI: 0.50 (0.47-0.54) p = .44, RA SDR: 0.54 (0.50-0.59) p = .62 or RAPSV: 0.51 (0.47-0.55) p = .54).Conclusion: The renal artery indices do not improve detection of fetuses at risk for adverse neonatal outcomes compared with the CPR or the UA PI.
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Affiliation(s)
- Stephen Contag
- Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology and Women's Health, University of Minnesota, Minneapolis, MN, USA
| | - Pooja Patel
- Division of Maternal Fetal Medicine, Department of Obstetrics, Gynecology and Reproductive Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Stephanie Payton
- Division of Maternal Fetal Medicine, Department of Obstetrics, Gynecology and Reproductive Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Sarah Crimmins
- Division of Maternal Fetal Medicine, Department of Obstetrics, Gynecology and Reproductive Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Katherine R Goetzinger
- Division of Maternal Fetal Medicine, Department of Obstetrics, Gynecology and Reproductive Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA
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9
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Pacora P, Romero R, Jaiman S, Erez O, Bhatti G, Panaitescu B, Benshalom-Tirosh N, Jung Jung E, Hsu CD, Hassan SS, Yeo L, Kadar N. Mechanisms of death in structurally normal stillbirths. J Perinat Med 2019; 47:222-240. [PMID: 30231013 PMCID: PMC6349478 DOI: 10.1515/jpm-2018-0216] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 07/20/2018] [Indexed: 01/05/2023]
Abstract
Objectives To investigate mechanisms of in utero death in normally formed fetuses by measuring amniotic fluid (AF) biomarkers for hypoxia (erythropoietin [EPO]), myocardial damage (cardiac troponin I [cTnI]) and brain injury (glial fibrillary acidic protein [GFAP]), correlated with risk factors for fetal death and placental histopathology. Methods This retrospective, observational cohort study included intrauterine deaths with transabdominal amniocentesis prior to induction of labor. Women with a normal pregnancy and an indicated amniocentesis at term were randomly selected as controls. AF was assayed for EPO, cTnI and GFAP using commercial immunoassays. Placental histopathology was reviewed, and CD15-immunohistochemistry was used. Analyte concentrations >90th centile for controls were considered "raised". Raised AF EPO, AF cTnI and AF GFAP concentrations were considered evidence of hypoxia, myocardial and brain injury, respectively. Results There were 60 cases and 60 controls. Hypoxia was present in 88% (53/60), myocardial damage in 70% (42/60) and brain injury in 45% (27/60) of fetal deaths. Hypoxic fetuses had evidence of myocardial injury, brain injury or both in 77% (41/53), 49% (26/53) and 13% (7/53) of cases, respectively. Histopathological evidence for placental dysfunction was found in 74% (43/58) of these cases. Conclusion Hypoxia, secondary to placental dysfunction, was found to be the mechanism of death in the majority of fetal deaths among structurally normal fetuses. Ninety-one percent of hypoxic fetal deaths sustained brain, myocardial or both brain and myocardial injuries in utero. Hypoxic myocardial injury was an attributable mechanism of death in 70% of the cases. Non-hypoxic cases may be caused by cardiac arrhythmia secondary to a cardiac conduction defect.
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Affiliation(s)
- Percy Pacora
- Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, Maryland, and Detroit, Michigan,Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, Michigan
| | - Roberto Romero
- Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, Maryland, and Detroit, Michigan,Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, Michigan,Department of Epidemiology and Biostatistics, Michigan State University, East Lansing, Michigan,Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan
| | - Sunil Jaiman
- Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, Maryland, and Detroit, Michigan,Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, Michigan
| | - Offer Erez
- Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, Maryland, and Detroit, Michigan,Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, Michigan,Department of Obstetrics and Gynecology, Soroka University Medical Center, School of Medicine, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beersheba, Israel
| | - Gaurav Bhatti
- Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, Maryland, and Detroit, Michigan,Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, Michigan
| | - Bogdan Panaitescu
- Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, Maryland, and Detroit, Michigan,Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, Michigan
| | - Neta Benshalom-Tirosh
- Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, Maryland, and Detroit, Michigan,Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, Michigan,Department of Obstetrics and Gynecology, Soroka University Medical Center, School of Medicine, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beersheba, Israel
| | - Eun Jung Jung
- Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, Maryland, and Detroit, Michigan,Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, Michigan
| | - Chaur-Dong Hsu
- Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, Michigan
| | - Sonia S. Hassan
- Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, Maryland, and Detroit, Michigan,Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, Michigan,Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan
| | - Lami Yeo
- Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, Maryland, and Detroit, Michigan,Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, Michigan
| | - Nicholas Kadar
- Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, Maryland, and Detroit, Michigan,Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, Michigan
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10
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Isolating the direct effects of adverse developmental conditions on in vivo cardiovascular function at adulthood: the avian model. J Dev Orig Health Dis 2018; 9:460-466. [PMID: 29692274 PMCID: PMC6075699 DOI: 10.1017/s2040174418000247] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
It is now well accepted that exposure to adverse environmental conditions in utero can predispose a fetus to disease later in life. Using an avian model to study the programming of disease has a unique advantage as it allows isolation of the direct effects of adverse conditions on fetal physiology, without any confounding effects via the mother or placenta. However, experiments in avian models are limited by the lack of well-established surgical protocols for the adult bird, which we have established in this study. Surgery was performed on seven young adult Bovan Brown chickens (body weight 1617±214 g, mean±s.d.) in order to instrument them with femoral arterial and venous catheters and a femoral arterial flow probe. Isoflurane and lidocaine were both found to have depressive effects on chicken cardiovascular function. Optimised methods of anaesthesia, intraoperative monitoring, surgical approach, postoperative care, and experimentation are described. Chickens recovered rapidly from surgery without significant blood gas perturbation, and basal in vivo cardiovascular studies were performed following 5 days of recovery. These techniques allow detailed investigation of avian cardiometabolic function, permitting determination of the consequences in later life of direct environmental insults to fetal physiology, isolated from additional effects on maternal physiology and/or placental endocrinology.
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11
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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: 226] [Impact Index Per Article: 28.3] [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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12
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Farías JG, Herrera EA, Carrasco-Pozo C, Sotomayor-Zárate R, Cruz G, Morales P, Castillo RL. Pharmacological models and approaches for pathophysiological conditions associated with hypoxia and oxidative stress. Pharmacol Ther 2015; 158:1-23. [PMID: 26617218 DOI: 10.1016/j.pharmthera.2015.11.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Hypoxia is the failure of oxygenation at the tissue level, where the reduced oxygen delivered is not enough to satisfy tissue demands. Metabolic depression is the physiological adaptation associated with reduced oxygen consumption, which evidently does not cause any harm to organs that are exposed to acute and short hypoxic insults. Oxidative stress (OS) refers to the imbalance between the generation of reactive oxygen species (ROS) and the ability of endogenous antioxidant systems to scavenge ROS, where ROS overwhelms the antioxidant capacity. Oxidative stress plays a crucial role in the pathogenesis of diseases related to hypoxia during intrauterine development and postnatal life. Thus, excessive ROS are implicated in the irreversible damage to cell membranes, DNA, and other cellular structures by oxidizing lipids, proteins, and nucleic acids. Here, we describe several pathophysiological conditions and in vivo and ex vivo models developed for the study of hypoxic and oxidative stress injury. We reviewed existing literature on the responses to hypoxia and oxidative stress of the cardiovascular, renal, reproductive, and central nervous systems, and discussed paradigms of chronic and intermittent hypobaric hypoxia. This systematic review is a critical analysis of the advantages in the application of some experimental strategies and their contributions leading to novel pharmacological therapies.
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Affiliation(s)
- Jorge G Farías
- Facultad de Ingeniería y Ciencias, Departamento de Ingeniería Química, Universidad de la Frontera, Casilla 54-D, Temuco, Chile
| | - Emilio A Herrera
- Programa de Fisiopatología, ICBM, Facultad de Medicina, Universidad de Chile, Chile; International Center for Andean Studies (INCAS), Universidad de Chile, Chile
| | | | - Ramón Sotomayor-Zárate
- Centro de Neurobiología y Plasticidad Cerebral (CNPC), Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Chile
| | - Gonzalo Cruz
- Centro de Neurobiología y Plasticidad Cerebral (CNPC), Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Chile
| | - Paola Morales
- Programa de Farmacología Molecular y Clínica, ICBM, Facultad de Medicina, Universidad de Chile, Chile
| | - Rodrigo L Castillo
- Programa de Fisiopatología, ICBM, Facultad de Medicina, Universidad de Chile, Chile.
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13
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Su EJ. Role of the fetoplacental endothelium in fetal growth restriction with abnormal umbilical artery Doppler velocimetry. Am J Obstet Gynecol 2015; 213:S123-30. [PMID: 26428491 DOI: 10.1016/j.ajog.2015.06.038] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 06/12/2015] [Accepted: 06/16/2015] [Indexed: 01/30/2023]
Abstract
Growth-restricted fetuses with absent or reversed end-diastolic velocities in the umbilical artery are at substantially increased risk for adverse perinatal and long-term outcome, even in comparison to growth-restricted fetuses with preserved end-diastolic velocities. Translational studies show that this Doppler velocimetry correlates with fetoplacental blood flow, with absent or reversed end-diastolic velocities signifying abnormally elevated resistance within the placental vasculature. The fetoplacental vasculature is unique in that it is not subject to autonomic regulation, unlike other vascular beds. Instead, humoral mediators, many of which are synthesized by local endothelial cells, regulate placental vascular resistance. Existing data demonstrate that in growth-restricted pregnancies complicated by absent or reversed umbilical artery end-diastolic velocities, an imbalance in production of these vasoactive substances occurs, favoring vasoconstriction. Morphologically, placentas from these pregnancies also demonstrate impaired angiogenesis, whereby vessels within the terminal villi are sparsely branched, abnormally thin, and elongated. This structural deviation from normal placental angiogenesis restricts blood flow and further contributes to elevated fetoplacental vascular resistance. Although considerable work has been done in the field of fetoplacental vascular development and function, much remains unknown about the mechanisms underlying impaired development and function of the human fetoplacental vasculature, especially in the context of severe fetal growth restriction with absent or reversed umbilical artery end-diastolic velocities. Fetoplacental endothelial cells are key regulators of angiogenesis and vasomotor tone. A thorough understanding of their role in placental vascular biology carries the significant potential of discovering clinically relevant and innovative approaches to prevention and treatment of fetal growth restriction with compromised umbilical artery end-diastolic velocities.
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14
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Thakor AS, Allison BJ, Niu Y, Botting KJ, Serón-Ferré M, Herrera EA, Giussani DA. Melatonin modulates the fetal cardiovascular defense response to acute hypoxia. J Pineal Res 2015; 59:80-90. [PMID: 25908097 PMCID: PMC4528231 DOI: 10.1111/jpi.12242] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2015] [Accepted: 04/20/2015] [Indexed: 12/12/2022]
Abstract
Experimental studies in animal models supporting protective effects on the fetus of melatonin in adverse pregnancy have prompted clinical trials in human pregnancy complicated by fetal growth restriction. However, the effects of melatonin on the fetal defense to acute hypoxia, such as that which may occur during labor, remain unknown. This translational study tested the hypothesis, in vivo, that melatonin modulates the fetal cardiometabolic defense responses to acute hypoxia in chronically instrumented late gestation fetal sheep via alterations in fetal nitric oxide (NO) bioavailability. Under anesthesia, 6 fetal sheep at 0.85 gestation were instrumented with vascular catheters and a Transonic flow probe around a femoral artery. Five days later, fetuses were exposed to acute hypoxia with or without melatonin treatment. Fetal blood was taken to determine blood gas and metabolic status and plasma catecholamine concentrations. Hypoxia during melatonin treatment was repeated during in vivo NO blockade with the NO clamp. This technique permits blockade of de novo synthesis of NO while compensating for the tonic production of the gas, thereby maintaining basal cardiovascular function. Melatonin suppressed the redistribution of blood flow away from peripheral circulations and the glycemic and plasma catecholamine responses to acute hypoxia. These are important components of the fetal brain sparing response to acute hypoxia. The effects of melatonin involved NO-dependent mechanisms as the responses were reverted by fetal treatment with the NO clamp. Melatonin modulates the in vivo fetal cardiometabolic responses to acute hypoxia by increasing NO bioavailability.
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Affiliation(s)
- Avnesh S Thakor
- Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge, UK
- Department of Radiology, Stanford University, Stanford, CA, USA
| | - Beth J Allison
- Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge, UK
| | - Youguo Niu
- Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge, UK
| | - Kimberley J Botting
- Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge, UK
| | - Maria Serón-Ferré
- Facultad de Medicina, Programa de Fisiopatología, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile
| | - Emilio A Herrera
- Facultad de Medicina, Programa de Fisiopatología, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile
| | - Dino A Giussani
- Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge, UK
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15
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Giussani DA, Niu Y, Herrera EA, Richter HG, Camm EJ, Thakor AS, Kane AD, Hansell JA, Brain KL, Skeffington KL, Itani N, Wooding FBP, Cross CM, Allison BJ. Heart Disease Link to Fetal Hypoxia and Oxidative Stress. ADVANCES IN FETAL AND NEONATAL PHYSIOLOGY 2014; 814:77-87. [DOI: 10.1007/978-1-4939-1031-1_7] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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16
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Kane AD, Hansell JA, Herrera EA, Allison BJ, Niu Y, Brain KL, Kaandorp JJ, Derks JB, Giussani DA. Xanthine oxidase and the fetal cardiovascular defence to hypoxia in late gestation ovine pregnancy. J Physiol 2013; 592:475-89. [PMID: 24247986 DOI: 10.1113/jphysiol.2013.264275] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Hypoxia is a common challenge to the fetus, promoting a physiological defence to redistribute blood flow towards the brain and away from peripheral circulations. During acute hypoxia, reactive oxygen species (ROS) interact with nitric oxide (NO) to provide an oxidant tone. This contributes to the mechanisms redistributing the fetal cardiac output, although the source of ROS is unknown. Here, we investigated whether ROS derived from xanthine oxidase (XO) contribute to the fetal peripheral vasoconstrictor response to hypoxia via interaction with NO-dependent mechanisms. Pregnant ewes and their fetuses were surgically prepared for long-term recording at 118 days of gestation (term approximately 145 days). After 5 days of recovery, mothers were infused i.v. for 30 min with either vehicle (n = 11), low dose (30 mg kg(-1), n = 5) or high dose (150 mg kg(-1), n = 9) allopurinol, or high dose allopurinol with fetal NO blockade (n = 6). Following allopurinol treatment, fetal hypoxia was induced by reducing maternal inspired O2 such that fetal basal P aO 2 decreased approximately by 50% for 30 min. Allopurinol inhibited the increase in fetal plasma uric acid and suppressed the fetal femoral vasoconstrictor, glycaemic and lactate acidaemic responses during hypoxia (all P < 0.05), effects that were restored to control levels with fetal NO blockade. The data provide evidence for the activation of fetal XO in vivo during hypoxia and for XO-derived ROS in contributing to the fetal peripheral vasoconstriction, part of the fetal defence to hypoxia. The data are of significance to the understanding of the physiological control of the fetal cardiovascular system during hypoxic stress. The findings are also of clinical relevance in the context of obstetric trials in which allopurinol is being administered to pregnant women when the fetus shows signs of hypoxic distress.
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Affiliation(s)
- Andrew D Kane
- Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK.
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17
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Herrera EA, Kane AD, Hansell JA, Thakor AS, Allison BJ, Niu Y, Giussani DA. A role for xanthine oxidase in the control of fetal cardiovascular function in late gestation sheep. J Physiol 2012; 590:1825-37. [PMID: 22331413 DOI: 10.1113/jphysiol.2011.224576] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Virtually nothing is known about the effects on fetal physiology of xanthine oxidase inhibition. This is despite maternal treatment with the xanthine oxidase inhibitor allopurinol being considered in human complicated pregnancy to protect the infant’s brain from excessive generation of ROS.We investigated the in vivo effects of maternal treatment with allopurinol on fetal cardiovascular function in ovine pregnancy in late gestation. Under anaesthesia, pregnant ewes and their singleton fetus were instrumented with vascular catheters and flow probes around an umbilical and a fetal femoral artery at 118±1 dGA (days of gestational age; termca. 145 days). Five days later, mothers were infused I.V. with either vehicle (n =11) or allopurinol (n =10). Fetal cardiovascular function was stimulated with increasing bolus doses of phenylephrine (PE) following maternal vehicle or allopurinol. The effects of maternal allopurinol on maternal and fetal cardiovascular function were also investigated following fetal NO blockade (n =6) or fetal β1-adrenergic antagonism (n =7). Maternal allopurinol led to significant increases in fetal heart rate, umbilical blood flow and umbilical vascular conductance, effects abolished by fetal β1-adrenergic antagonism but not by fetal NO blockade. Maternal allopurinol impaired fetal α1-adrenergic pressor and femoral vasopressor responses and enhanced the gain of the fetal cardiac baroreflex. These effects of maternal allopurinol were restored to control levels during fetal NO blockade. Maternal treatment with allopurinol induced maternal hypotension, tachycardia and acid–base disturbance. We conclude that maternal treatment with allopurinol alters in vivo maternal, umbilical and fetal vascular function via mechanisms involving NO and β1-adrenergic stimulation. The evidence suggests that the use of allopurinol in clinical practice should be approached with caution.
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Affiliation(s)
- E A Herrera
- Department of Physiology Development & Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK
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18
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Kane AD, Herrera EA, Hansell JA, Giussani DA. Statin treatment depresses the fetal defence to acute hypoxia via increasing nitric oxide bioavailability. J Physiol 2011; 590:323-34. [PMID: 22106179 DOI: 10.1113/jphysiol.2011.217968] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
In addition to lowering cholesterol, statins increase nitric oxide (NO) bioavailability, improving endothelial function. In the fetus, enhanced NO during acute hypoxia opposes the fetal peripheral vasoconstrictor response, part of the brain-sparing defence. This study tested the hypothesis that treatment with statins depresses the fetal circulatory response to acute hypoxic stress via increasing NO bioavailability. Under anaesthesia, 12 fetal sheep at 118 ± 1 days of gestation (term ca 145 days) were instrumented with vascular catheters and a femoral artery Transonic flow probe for chronic recording. Five days later, all animals were subjected to 30 min of acute hypoxia (fetal arterial partial pressure of O(2) ( ) reduced by ca 50%) before and 24 h after fetal treatment with pravastatin (25 mg i.v.). In half of the fetuses (n = 6), responses to hypoxia post-pravastatin were evaluated during NO synthesis blockade. Fetal exposure to pravastatin did not affect fetal basal cardiovascular function. Fetal was similarly reduced in all acute hypoxia experiments from ca 21 to 10 mmHg. Fetal exposure to pravastatin markedly diminished the fetal femoral vasoconstrictor (5.1 ± 0.9 vs. 2.5 ± 0.5 mmHg (ml min(-1))(-1)) and lactic acidaemic (4.4 ± 0.5 vs. 3.0 ± 0.3 mm) responses to acute hypoxia (both P < 0.05), without affecting plasma catecholamine responses. Post-pravastatin, the circulatory (5.8 ± 1.5 mmHg (ml min(-1))(-1)) and metabolic (3.9 ± 0.3 mm) responses could be restored to control levels during fetal treatment with NO synthase blockade. Pravastatin depresses the fetal cardiovascular and metabolic defences to acute hypoxia via increasing NO bioavailability. The use of statins during pregnancy should be viewed with extreme caution.
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Affiliation(s)
- Andrew D Kane
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK
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19
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Thompson JA, Gimbel SA, Richardson BS, Gagnon R, Regnault TRH. The Effect of Intermittent Umbilical Cord Occlusion on Elastin Composition in the Ovine Fetus. Reprod Sci 2011; 18:990-7. [DOI: 10.1177/1933719111401655] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Jennifer A. Thompson
- Department of Physiology, The University of Western Ontario, London, Ontario, Canada
| | - Sarah A. Gimbel
- Department of Obstetrics and Gynecology, The University of Western Ontario, London, Ontario, Canada
| | - Bryan S. Richardson
- Department of Physiology, The University of Western Ontario, London, Ontario, Canada
- Department of Obstetrics and Gynecology, The University of Western Ontario, London, Ontario, Canada
| | - Robert Gagnon
- Department of Obstetrics and Gynecology, McGill University, Montreal, Quebec, Canada
| | - Timothy R. H. Regnault
- Department of Physiology, The University of Western Ontario, London, Ontario, Canada
- Department of Obstetrics and Gynecology, The University of Western Ontario, London, Ontario, Canada
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20
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Thakor AS, Herrera EA, Serón-Ferré M, Giussani DA. Melatonin and vitamin C increase umbilical blood flow via nitric oxide-dependent mechanisms. J Pineal Res 2010; 49:399-406. [PMID: 20958954 DOI: 10.1111/j.1600-079x.2010.00813.x] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Inadequate umbilical blood flow leads to intrauterine growth restriction, a major killer in perinatal medicine today. Nitric oxide (NO) is important in the maintenance of umbilical blood flow, and antioxidants increase NO bioavailability. What remains unknown is whether antioxidants can increase umbilical blood flow. Melatonin participates in circadian, seasonal, and reproductive physiology, but has also been reported to act as a potent endogenous antioxidant. We tested the hypothesis that treatment during pregnancy with melatonin increases umbilical blood flow via NO-dependent mechanisms. This was tested in pregnant sheep by investigating in vivo the effects on continuous measurement of umbilical blood flow of melatonin before and after NO blockade with a NO clamp. These effects of melatonin were compared with those of the traditional antioxidant, vitamin C. Under anesthesia, 12 pregnant sheep and their fetuses (0.8 of gestation) were fitted with catheters and a Transonic probe around an umbilical artery, inside the fetal abdomen. Following 5 days of recovery, cardiovascular variables were recorded during fetal i.v. treatment with either melatonin (n=6, 0.5±0.1 μg/kg/min) or vitamin C (n=6, 8.9±0.4 mg/kg/min) before and after fetal NO blockade with the NO clamp. Fetal treatment with melatonin or vitamin C increased umbilical blood flow, independent of changes in fetal arterial blood pressure. Fetal NO blockade prevented the increase in umbilical blood flow induced by melatonin or vitamin C. Antioxidant treatment could be a useful clinical tool to increase or maintain umbilical blood flow in complicated pregnancy.
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Affiliation(s)
- Avnesh S Thakor
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
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21
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Dyer JL, McMillen IC, Warnes KE, Morrison JL. No evidence for an enhanced role of endothelial nitric oxide in the maintenance of arterial blood pressure in the IUGR sheep fetus. Placenta 2009; 30:705-10. [PMID: 19515421 DOI: 10.1016/j.placenta.2009.05.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2009] [Revised: 04/15/2009] [Accepted: 05/07/2009] [Indexed: 01/21/2023]
Abstract
The fetus makes a number of physiological adaptations to a restriction of placental substrate supply, including a decrease in body growth and an increase in peripheral vasoconstriction which maintains mean arterial pressure (MAP) and supports a redistribution of cardiac output to key fetal organs. It is not known, however, whether chronic restriction of placental substrate supply results in an enhanced or diminished role for vasodilators such as endothelial nitric oxide in the regulation of MAP. We hypothesised that there is an increased contribution of NO to blood pressure regulation in growth restricted fetuses and that a 2h infusion of a nitric oxide synthase inhibitor, N(omega)-nitro-l-arginine methyl ester (l-NAME) would result in an augmented rise in MAP in chronically hypoxemic, placentally restricted (PR, n=8) fetuses compared to controls (n=6) in late gestation. There was no difference in the increase in fetal MAP and decrease in HR during l-NAME infusion between Control and PR fetuses. In the PR group, fetuses with lower mean gestational PaO(2) had a lower increase in MAP during l-NAME infusion. Thus we have found no evidence for an enhanced role of NO in the maintenance of MAP in the chronically hypoxemic IUGR fetus.
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Affiliation(s)
- J L Dyer
- Discipline of Physiology, University of Adelaide, Adelaide, SA 5005, Australia
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22
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Abstract
Goals to understand the etiology of essential hypertension have proposed that this problem arises, in part, because of changes within brainstem circuits involved in arterial blood pressure (ABP) control. It has been suggested that nitric oxide (NO) exerts inhibitory influences on the integration of afferent discharge from the arterial baroreceptors. This study tested the hypothesis that the inhibitory influence of NO on the arterial baroreflex is present in fetal life. Fetal baroreflex sensitivity was calculated in fetal sheep, before and during the NO-clamp; a technique that permits NO synthase (NOS) blockade with l-NAME while maintaining basal cardiovascular function with sodium nitroprusside. Under halothane anesthesia, five fetal sheep at 0.8 gestation were instrumented with vascular catheters. Five days later, fetuses received a range of bolus doses of phenylephrine (5-75 microg I.A.) in randomized order either during saline or treatment with the NO clamp. Basal fetal ABP and heart rate before (50 +/- 4 mm Hg, 170 +/- 3 bpm) or during (51 +/- 4 mm Hg, 173 +/- 3 bpm) the NO-clamp were similar. The gradient of the pulse interval-ABP relationship was nearly doubled during NOS blockade (14.2 =/- 2.5 versus 7.8 +/- 1.6 ms/mm Hg). The data provide in vivo evidence that NO attenuates the sensitivity of the cardiac baroreflex during fetal life.
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Affiliation(s)
- Avnesh S Thakor
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, United Kingdom
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Thakor AS, Giussani DA. Role of Nitric Oxide in Mediating In Vivo Vascular Responses to Calcitonin Gene-Related Peptide in Essential and Peripheral Circulations in the Fetus. Circulation 2005; 112:2510-6. [PMID: 16216959 DOI: 10.1161/circulationaha.105.562546] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background—
The role of calcitonin gene-related peptide (CGRP) in cardiovascular regulation is gaining clinical and scientific interest. In the adult, in vivo studies have shown that CGRP-stimulated vasodilation in several vascular beds depends, at least in part, on nitric oxide (NO). However, whether CGRP acts as a vasodilator in the fetus in vivo and whether this effect is mediated via NO have been addressed only minimally. This study tested the hypothesis that CGRP has potent NO-dependent vasodilator actions in essential and peripheral vascular beds in the fetus in late gestation.
Methods and Results—
Under anesthesia, 5 fetal sheep at 0.8 gestation were instrumented with vascular catheters and Transonic flow probes around an umbilical artery and a femoral artery. Five days later, fetuses received 2- and 5-μg doses of exogenous CGRP intra-arterially in randomized order. Doses were repeated during NO blockade with the NO clamp. This technique permits blockade of de novo synthesis of NO while compensating for tonic production of the gas, thereby maintaining basal cardiovascular function. CGRP resulted in potent and long-lasting NO-dependent dilation in the umbilical and femoral circulations, hypotension, and a positive cardiac chronotropic effect. During NO blockade, the femoral vasodilator response to CGRP was diminished. In contrast, in the umbilical vascular bed, the dilator response was not only prevented but reversed to vasoconstriction.
Conclusions—
CGRP has potent NO-dependent vasodilator actions in fetal essential and peripheral vascular beds. CGRP-induced NO-dependent effects in the umbilical vascular bed may provide an important mechanism in the control and maintenance of umbilical blood flow during pregnancy.
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Affiliation(s)
- A S Thakor
- Department of Physiology, University of Cambridge, Cambridge, CB2 3EG, UK
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Giussani DA, Thakor AS, Frulio R, Gazzolo D. Acute hypoxia increases S100beta protein in association with blood flow redistribution away from peripheral circulations in fetal sheep. Pediatr Res 2005; 58:179-84. [PMID: 16006424 DOI: 10.1203/01.pdr.0000169999.66157.c0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We investigated in fetal sheep during late gestation the effects of acute hypoxemia on fetal plasma S100beta protein concentrations and how these relate to fetal redistribution of blood flow and acid-base status. Under general anesthesia, five Welsh Mountain sheep fetuses were instrumented with vascular catheters, and transit-time flow transducers were implanted around a femoral artery and an umbilical artery. At least 5 d after surgery, fetuses were subjected to 1 h of normoxia, 0.5 h of hypoxemia, and 1 h of recovery. Hypoxemia induced significant falls in fetal pH(a), arterial oxygen pressure, acid-base excess, and [HCO(3)(-)], without alteration to arterial partial pressure of carbon dioxide. An increase in arterial blood pressure, a fall in heart rate, an increase in femoral vascular resistance, and a decrease in umbilical vascular resistance occurred in all fetuses. During hypoxemia, plasma S100beta increased significantly and remained elevated until the end of the protocol. Within individual fetuses, plasma S100beta correlated with femoral vascular resistance and pH. In contrast, no relationship was found between S100beta and umbilical vascular resistance. This study reports for the first time that a controlled period of fetal hypoxemia with associated acidemia leads to persistent elevations in plasma S100beta concentrations that strongly correlate with hemodynamic changes that are known to occur during fetal blood flow redistribution. These findings open up a new role for changes in fetal S100beta concentrations as a possible early marker of fetal hypoxia with associated acidemia in perinatal medicine.
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Affiliation(s)
- Dino A Giussani
- Department of Physiology, University of Cambridge, Cambridge, CB2 3EG, United Kingdom.
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Thakor AS, Giussani DA. Calcitonin gene-related peptide contributes to the umbilical haemodynamic defence response to acute hypoxaemia. J Physiol 2004; 563:309-17. [PMID: 15611032 PMCID: PMC1665566 DOI: 10.1113/jphysiol.2004.077024] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Despite clinical advances in obstetric practice, undiagnosed fetal hypoxaemia still contributes to a high incidence of perinatal morbidity. The fetal defence to hypoxaemia involves a redistribution of blood flow away from peripheral circulations towards essential vascular beds, such as the umbilical, cerebral, myocardial and adrenal circulations. In marked contrast to other essential vascular beds, the mechanisms mediating maintained perfusion of the umbilical circulation during hypoxaemia remain unknown. This study determined the role of calcitonin gene-related peptide (CGRP) in the maintenance of umbilical blood flow during basal and hypoxaemic conditions. Under anaesthesia, five sheep fetuses were instrumented with catheters and a Transonic probe around an umbilical artery, inside the fetal abdomen, at 0.8 of gestation. 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. The CGRP antagonist did not alter basal blood gas or cardiovascular status in the fetus. A similar fall in Pa,O2 occurred in fetuses during either saline (21 +/- 0.8 to 9 +/- 0.9 mmHg) or antagonist treatment (20 +/- 0.9 to 9 +/- 1.2 mmHg). Hypoxaemia during saline led to significant increases in arterial blood pressure, umbilical blood flow and umbilical vascular conductance. In marked contrast, hypoxaemia during CGRP antagonist treatment led to pronounced falls in both umbilical blood flow and umbilical vascular conductance without affecting the magnitude of the hypertensive response. In conclusion, CGRP plays an important role in the umbilical haemodynamic defence response to hypoxaemia in the late gestation fetus.
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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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Abstract
Considering the life-long influences of fetal growth biology, it is of interest to further elucidate the nature of the fetal growth process itself. Previous analyses of longitudinal fetal ultrasound data led to the hypothesis that hypoxia signals were important aspects of normal growth biology and directed attention to the place of oxygen as a basic nutrient. From the perspective of the cell, both hypoxia and lack of energy substrate trigger a common adaptive pathway through their effects on ATP availability. Comparative data from animal studies and cell culture provide evidence for an integrated energy/oxygen signaling system that acts redundantly and hierarchically with cellular differentiation programs, providing opportunities for developmental flexibility in response to variable ecologic or environmental challenge. The multinodal and interactive design of the fetal growth process suggests that it follows what has been described as the "bow tie" model of metabolism, with implications for robust and inventive approaches to cell, organ, and whole organism construction.
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Affiliation(s)
- Michelle Lampl
- Department of Anthropology, Emory University, Atlanta, Georgia 30322, USA.
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