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Bates ML, Levy PT, Nuyt AM, Goss KN, Lewandowski AJ, McNamara PJ. Adult Cardiovascular Health Risk and Cardiovascular Phenotypes of Prematurity. J Pediatr 2020; 227:17-30. [PMID: 32931771 DOI: 10.1016/j.jpeds.2020.09.019] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 08/25/2020] [Accepted: 09/09/2020] [Indexed: 02/07/2023]
Affiliation(s)
- Melissa L Bates
- Department of Health and Human Physiology, University of Iowa, Iowa City, IA; Division of Neonatology, Stead Family Department of Pediatrics, University of Iowa, Iowa City, IA
| | - Philip T Levy
- Division of Newborn Medicine, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, MA.
| | - Anne Monique Nuyt
- Division of Neonatology, Department of Pediatrics, CHU Sainte-Justine, Faculty of Medicine, Université de Montréal, Montréal, Quebec, Canada
| | - Kara N Goss
- Department of Pediatrics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI; Department of Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI
| | - Adam J Lewandowski
- Oxford Cardiovascular Clinical Research Facility, Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Patrick J McNamara
- Division of Neonatology, Stead Family Department of Pediatrics, University of Iowa, Iowa City, IA
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Garabedian C, Clermont-Hama Y, Sharma D, Aubry E, Butruille L, Deruelle P, Storme L, De Jonckheere J, Houfflin-Debarge V. Correlation of a new index reflecting the fluctuation of parasympathetic tone and fetal acidosis in an experimental study in a sheep model. PLoS One 2018; 13:e0190463. [PMID: 29320537 PMCID: PMC5761865 DOI: 10.1371/journal.pone.0190463] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Accepted: 11/20/2017] [Indexed: 12/21/2022] Open
Abstract
The autonomic nervous system plays a leading role in the control of fetal homeostasis. Fetal heart rate variability (HRV) analysis is a reflection of its activity. We developed a new index (the Fetal Stress Index, FSI) reflecting parasympathetic tone. The objective of this study was to evaluate this index as a predictor of fetal acid-base status. This was an experimental study on chronically instrumented fetal lambs (n = 11, surgery at 128 +/- 2 days gestational age, term = 145 days). The model was based on 75% occlusion of the umbilical cord for a maximum of 120 minutes or until an arterial pH ≤ 7.20 was reached. Hemodynamic, gasometric and FSI parameters were recorded throughout the experimentation. We studied the FSI during the 10 minutes prior to pH samplings and compared values for pH>7.20 and pH≤ 7.20. In order to analyze the FSI evolution during the 10 minutes periods, we analyzed the minimum, maximum and mean values of the FSI (respectively FSImin, FSImax and FSImean) over the periods. 11 experimentations were performed. During occlusion, the heart rate dropped with an increase in blood pressure (respectively 160(155-182) vs 106(101-120) bpm and 42(41-45) vs 58(55-62) mmHg after occlusion). The FSImin was 38.6 (35.2-43.3) in the group pH>7.20 and was higher in the group pH less than 7.20 (46.5 (43.3-52.0), p = 0.012). The correlation of FSImin was significant for arterial pH (coefficient of -0.671; p = 0.004) and for base excess (coefficient of -0.632; p = 0.009). The correlations were not significant for the other parameters. In conclusion, our new index seems well correlated with the fetal acid-base status. Other studies must be carried out in a situation close to the physiology of labor by sequential occlusion of the cord.
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Affiliation(s)
- C. Garabedian
- Univ. Lille, EA 4489 –Perinatal Environment and Health, Lille, France
- CHU Lille, Department of Obstetrics, Lille, France
- * E-mail:
| | - Y. Clermont-Hama
- Univ. Lille, EA 4489 –Perinatal Environment and Health, Lille, France
- CHU Lille, Department of Obstetrics, Lille, France
| | - D. Sharma
- Univ. Lille, EA 4489 –Perinatal Environment and Health, Lille, France
- CHU Lille, Department of Pediatric Surgery, Lille, France
| | - E. Aubry
- Univ. Lille, EA 4489 –Perinatal Environment and Health, Lille, France
- CHU Lille, Department of Pediatric Surgery, Lille, France
| | - L. Butruille
- Univ. Lille, EA 4489 –Perinatal Environment and Health, Lille, France
| | - P. Deruelle
- Univ. Lille, EA 4489 –Perinatal Environment and Health, Lille, France
- CHU Lille, Department of Obstetrics, Lille, France
| | - L. Storme
- Univ. Lille, EA 4489 –Perinatal Environment and Health, Lille, France
- CHU Lille, Department of Neonatology, Lille, France
| | - J. De Jonckheere
- Univ. Lille, EA 4489 –Perinatal Environment and Health, Lille, France
- CHU Lille, CIC-IT 1403, Lille, France
| | - V. Houfflin-Debarge
- Univ. Lille, EA 4489 –Perinatal Environment and Health, Lille, France
- CHU Lille, Department of Obstetrics, Lille, France
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Allison BJ, Nguyen V, Yiallourou SR, Nitsos I, Black MJ, Polglase GR. The effect of sex and prematurity on the cardiovascular baroreflex response in sheep. Exp Physiol 2018; 103:9-18. [PMID: 29072344 DOI: 10.1113/ep086494] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 10/13/2017] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? Late preterm infants are often assumed to escape long-term morbidities known to impact earlier preterm offspring. Is this true for the cardiovascular system? What is the main finding and its importance? We show that late preterm birth is a risk factor for cardiovascular dysfunction in early adulthood and is influenced by sex. Early signs of cardiovascular dysfunction might predispose to heart disease in adulthood. Very preterm infants have an increased risk of cardiovascular disease; however, the effects of a late preterm birth on future cardiovascular function are not known. We hypothesized that after a late preterm birth, the well-described impairments in heart rate variability and baroreflex sensitivity would persist into adulthood. To test this hypothesis, sheep born preterm (0.9 gestation; nine male and seven female) or term (11 male and six female) underwent surgery at 14 months of age for insertion of femoral arterial and venous catheters and a femoral flow probe. After recovery, heart rate variability was assessed, followed by a baroreflex challenge (using the vasoactive agents phenylephrine and sodium nitroprusside) in conscious adult lambs. Our data demonstrate decreased low-frequency normalised units (LFnu) and low-frequency/high-frequency ratio in female but not male ex-preterm sheep at rest. When challenged, mature male ex-preterm sheep have an increased blood pressure response but dampened heart rate baroreflex response. We show that even a late preterm birth leads to cardiovascular dysfunction in adulthood. These early signs of cardiovascular dysfunction might underpin the later hypertension and increased risk of heart disease observed in adults born preterm. These findings are particularly important because late preterm infants are often assumed to escape the long-term morbidities known to impact on very preterm and extremely preterm offspring.
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Affiliation(s)
- Beth J Allison
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia.,Department of Obstetrics and Gynecology, Monash University, Clayton, Victoria, Australia
| | - Vivian Nguyen
- Department of Anatomy and Developmental Biology and Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Stephanie R Yiallourou
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia.,Department of Obstetrics and Gynecology, Monash University, Clayton, Victoria, Australia
| | - Ilias Nitsos
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
| | - Mary Jane Black
- Department of Anatomy and Developmental Biology and Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Graeme R Polglase
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia.,Department of Obstetrics and Gynecology, Monash University, Clayton, Victoria, Australia
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Lear CA, Galinsky R, Wassink G, Yamaguchi K, Davidson JO, Westgate JA, Bennet L, Gunn AJ. The myths and physiology surrounding intrapartum decelerations: the critical role of the peripheral chemoreflex. J Physiol 2016; 594:4711-25. [PMID: 27328617 DOI: 10.1113/jp271205] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2015] [Accepted: 02/17/2016] [Indexed: 11/08/2022] Open
Abstract
A distinctive pattern of recurrent rapid falls in fetal heart rate, called decelerations, are commonly associated with uterine contractions during labour. These brief decelerations are mediated by vagal activation. The reflex triggering this vagal response has been variably attributed to a mechanoreceptor response to fetal head compression, to baroreflex activation following increased blood pressure during umbilical cord compression, and/or a Bezold-Jarisch reflex response to reduced venous return from the placenta. Although these complex explanations are still widespread today, there is no consistent evidence that they are common during labour. Instead, the only mechanism that has been systematically investigated, proven to be reliably active during labour and, crucially, capable of producing rapid decelerations is the peripheral chemoreflex. The peripheral chemoreflex is triggered by transient periods of asphyxia that are a normal phenomenon associated with all uterine contractions. This should not cause concern as the healthy fetus has a remarkable ability to adapt to these repeated but short periods of asphyxia. This means that the healthy fetus is typically not at risk of hypotension and injury during uncomplicated labour even during repeated brief decelerations. The physiologically incorrect theories surrounding decelerations that ignore the natural occurrence of repeated asphyxia probably gained widespread support to help explain why many babies are born healthy despite repeated decelerations during labour. We propose that a unified and physiological understanding of intrapartum decelerations that accepts the true nature of labour is critical to improve interpretation of intrapartum fetal heart rate patterns.
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Affiliation(s)
- Christopher A Lear
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Robert Galinsky
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Guido Wassink
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Kyohei Yamaguchi
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand.,Department of Obstetrics and Gynaecology, Mie University Graduate School of Medicine, Mie, Japan
| | - Joanne O Davidson
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Jenny A Westgate
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand.,Department of Obstetrics and Gynaecology, The University of Auckland, Auckland, New Zealand
| | - Laura Bennet
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Alistair J Gunn
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand.,Starship Children's Hospital, Auckland, New Zealand
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Sandgren J, Scholz TD, Segar JL. ANG II modulation of cardiac growth and remodeling in immature fetal sheep. Am J Physiol Regul Integr Comp Physiol 2015; 308:R965-72. [PMID: 25810382 DOI: 10.1152/ajpregu.00034.2015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 03/20/2015] [Indexed: 01/09/2023]
Abstract
ANG II increases fetal blood pressure and stimulates fetal heart growth; however, little is known regarding its direct effects on cardiomyocytes in vivo. We sought to determine whether ANG II stimulates heart growth and cardiomyocyte hypertrophy and/or hyperplasia in utero in the immature fetal heart independent of the effects on cardiac afterload. In twin gestation, fetal sheep at ∼100 days gestation (term 145 days), one fetus received a chronic (6 days) infusion of ANG II alone (50 μg·kg(-1)·min(-1)) or ANG II plus nitroprusside (NTP) to attenuate the increase in blood pressure; noninstrumented twins served as controls. ANG II alone, but not ANG II + NTP resulted in a significant increase in heart mass (left and right ventricle + septum, corrected for body weight) compared with controls. ANG II, but not ANG II+NTP, also significantly increased cardiomyocyte area compared with control and increased the percentage of binucleated myocytes. ANG II with or without concomitant infusion of NTP increased cardiac PCNA expression, a marker of proliferation. Steady-state protein expression of terminal mitogen-activated protein kinases, cyclin B1, cyclin E1, and p21 were similar among groups. We conclude that in vivo, ANG II increases fetal cardiac mass via cardiomyocyte hypertrophy, differentiation, and to a lesser extent hyperplasia. The effects of ANG II on hypertrophy appear dependent upon the increase in blood pressure (mechanical load), whereas effects on proliferation are load-independent.
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Affiliation(s)
- Jeremy Sandgren
- Stead Family Department of Pediatrics, University of Iowa Carver College of Medicine, Iowa City, Iowa
| | - Thomas D Scholz
- Stead Family Department of Pediatrics, University of Iowa Carver College of Medicine, Iowa City, Iowa
| | - Jeffrey L Segar
- Stead Family Department of Pediatrics, University of Iowa Carver College of Medicine, Iowa City, Iowa
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Heart rate-mediated blood pressure control in preterm fetal sheep under normal and hypoxic-ischemic conditions. Pediatr Res 2013; 73:420-6. [PMID: 23340656 DOI: 10.1038/pr.2013.15] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND The understanding of hypoxemia-induced changes in baroreflex function is limited and may be studied in a fetal sheep experiment before, during, and after standardized hypoxic conditions. METHODS Preterm fetal lambs were instrumented at 102 d gestation (term: 146 d). At 106 d, intrauterine hypoxia--ischemia was induced by 25 min of umbilical cord occlusion (UCO). Baroreflex-related fluctuations were calculated at 30-min intervals during the first week after UCO by transfer function (cross-spectral) analysis between systolic blood pressure (SBP) and R-R interval fluctuations, estimated in the low-frequency (LF, 0.04-0.15 Hz) band. LF transfer gain (baroreflex sensitivity) and delay (s) reflect the baroreflex function. RESULTS Baseline did not differ in LF transfer gain and delay between controls and the UCO group. In controls, LF gain showed postnatal increase. By contrast, LF gain gradually decreased in the UCO group, resulting in significantly lower values 4-7 d after UCO. In the UCO group, LF delay increased and differed significantly from controls. CONCLUSION Our results show that intrauterine hypoxia-ischemia results in reduced baroreflex sensitivity over a period of 7 d, indicating limited efficacy to buffer BP changes by adapting heart rate. Cardiovascular dysregulation may augment already present cerebral damage after systemic hypoxia-ischemia in the reperfusion period.
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Bennet L, Booth LC, Drury PP, Quaedackers JSL, Gunn AJ. Preterm neonatal cardiovascular instability: Does understanding the fetus help evaluate the newborn? Clin Exp Pharmacol Physiol 2012; 39:965-72. [DOI: 10.1111/j.1440-1681.2012.05744.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Laura Bennet
- Fetal Physiology and Neuroscience Group; Department of Physiology; Faculty of Medical and Health; The University of Auckland; Auckland; New Zealand
| | - Lindsea C Booth
- Neurobiology Division; Florey Neuroscience Institutes; University of Melbourne; Melbourne; Victoria; Australia
| | - Paul P Drury
- Fetal Physiology and Neuroscience Group; Department of Physiology; Faculty of Medical and Health; The University of Auckland; Auckland; New Zealand
| | - Josine SL Quaedackers
- Fetal Physiology and Neuroscience Group; Department of Physiology; Faculty of Medical and Health; The University of Auckland; Auckland; New Zealand
| | - Alistair J Gunn
- Fetal Physiology and Neuroscience Group; Department of Physiology; Faculty of Medical and Health; The University of Auckland; Auckland; New Zealand
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Uemura K, Shimazutsu K, McClaine RJ, McClaine DJ, Manson RJ, White WD, Benni PB, Reynolds JD. Maternal and preterm fetal sheep responses to dexmedetomidine. Int J Obstet Anesth 2012; 21:339-47. [PMID: 22938943 DOI: 10.1016/j.ijoa.2012.06.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2012] [Revised: 06/12/2012] [Accepted: 06/19/2012] [Indexed: 11/28/2022]
Abstract
BACKGROUND The α(2) adrenergic receptor agonist dexmedetomidine has some unique pharmacologic properties that could benefit pregnant patients (and their fetuses) when they require sedation, analgesia, and/or anesthesia during pregnancy. The purpose of the present study was to delineate maternal and fetal responses to an intravenous infusion of dexmedetomidine. METHODS This study was conducted on surgically-recovered preterm sheep instrumented for physiologic recording and blood sampling. Maternal and fetal cardiovascular and blood gas parameters and fetal cerebral oxygenation levels were recorded before, during, and after 3h of dexmedetomidine infusion to the ewe at a rate of 1 μg/kg/h. RESULTS Drug infusion produced overt sedation but no apparent respiratory depression as evidenced by stable maternal arterial blood gases; fetal blood gases were also stable. The one blood parameter to change was serum glucose, By the end of the 3-h infusion, glucose increased from 49±10 to 104±33mg/dL in the ewe and from 22±3 to 48±16mg/dL in the fetus; it declined post-drug exposure but remained elevated compared to the starting levels (maternal, 63±12mg/dL, P=0.0497; and fetal, 24±4mg/dL, P=0.012). With respect to cardiovascular status, dexmedetomidine produced a decrease in maternal blood pressure and heart rate with fluctuations in uterine blood flow but had no discernable effect on fetal heart rate or mean arterial pressure. Likewise, maternal drug infusion had no effect on fetal cerebral oxygenation, as measured by in utero near-infrared spectroscopy. CONCLUSIONS Using a clinically-relevant dosing regimen, intravenous infusion of dexmedetomidine produced significant maternal sedation without altering fetal physiologic status. Results from this initial acute assessment support the conduct of further studies to determine if dexmedetomidine has clinical utility for sedation and pain control during pregnancy.
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Affiliation(s)
- K Uemura
- Department of Anesthesiology, Duke University Medical Centre, Durham, NC, USA
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Booth LC, Gunn AJ, Malpas SC, Barrett CJ, Davidson JO, Guild SJ, Bennet L. Baroreflex control of renal sympathetic nerve activity and heart rate in near-term fetal sheep. Exp Physiol 2011; 96:736-44. [DOI: 10.1113/expphysiol.2011.058354] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Booth LC, Bennet L, Guild SJ, Barrett CJ, May CN, Gunn AJ, Malpas SC. Maturation-related changes in the pattern of renal sympathetic nerve activity from fetal life to adulthood. Exp Physiol 2010; 96:85-93. [DOI: 10.1113/expphysiol.2010.055236] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Malpas SC. Sympathetic nervous system overactivity and its role in the development of cardiovascular disease. Physiol Rev 2010; 90:513-57. [PMID: 20393193 DOI: 10.1152/physrev.00007.2009] [Citation(s) in RCA: 431] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
This review examines how the sympathetic nervous system plays a major role in the regulation of cardiovascular function over multiple time scales. This is achieved through differential regulation of sympathetic outflow to a variety of organs. This differential control is a product of the topographical organization of the central nervous system and a myriad of afferent inputs. Together this organization produces sympathetic responses tailored to match stimuli. The long-term control of sympathetic nerve activity (SNA) is an area of considerable interest and involves a variety of mediators acting in a quite distinct fashion. These mediators include arterial baroreflexes, angiotensin II, blood volume and osmolarity, and a host of humoral factors. A key feature of many cardiovascular diseases is increased SNA. However, rather than there being a generalized increase in SNA, it is organ specific, in particular to the heart and kidneys. These increases in regional SNA are associated with increased mortality. Understanding the regulation of organ-specific SNA is likely to offer new targets for drug therapy. There is a need for the research community to develop better animal models and technologies that reflect the disease progression seen in humans. A particular focus is required on models in which SNA is chronically elevated.
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Affiliation(s)
- Simon C Malpas
- Department of Physiology and the Auckland Bioengineering Institute, University of Auckland and Telemetry Research Ltd., Auckland, New Zealand.
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Abstract
The third stage of labour is defined as the period following the completed delivery of the newborn until the completed delivery of the placenta and its attached membranes. Whilst to the exhausted labouring woman this stage may be an afterthought, it is a crucial time for fetal-to-neonatal transition. Major changes in anatomy and physiology occur in both mother and baby. It has also been described as ‘potentially the most hazardous part of childbirth, largely due to the risk of postpartum haemorrhage (PPH) on placental separation. Despite this, the current management guidelines are based on an ‘eclectic combination of historical, anecdotal, philosophical and research-based factors.
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