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Zhou KQ, Dhillon SK, Bennet L, Davidson JO, Gunn AJ. How do we reach the goal of personalized medicine for neuroprotection in neonatal hypoxic-ischemic encephalopathy? Semin Perinatol 2024; 48:151930. [PMID: 38910063 DOI: 10.1016/j.semperi.2024.151930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 06/25/2024]
Abstract
Therapeutic hypothermia is now standard of care for neonates with hypoxic-ischemic encephalopathy (HIE) in high income countries (HIC). Conversely, compelling trial evidence suggests that hypothermia is ineffective, and may be deleterious, in low- and middle-income countries (LMIC), likely reflecting the lower proportion of infants who had sentinel events at birth, suggesting that injury had advanced to a stage when hypothermia is no longer effective. Although hypothermia significantly reduced the risk of death and disability in HICs, many infants survived with disability and in principle may benefit from targeted add-on neuroprotective or neurorestorative therapies. The present review will assess biomarkers that could be used to personalize treatment for babies with HIE - to determine first whether an individual infant is likely to respond to hypothermia, and second, whether additional treatments may be beneficial.
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Affiliation(s)
- Kelly Q Zhou
- Dept of Physiology, The University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Simerdeep K Dhillon
- Dept of Physiology, The University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Laura Bennet
- Dept of Physiology, The University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Joanne O Davidson
- Dept of Physiology, The University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Alistair J Gunn
- Dept of Physiology, The University of Auckland, Private Bag 92019, Auckland, New Zealand.
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2
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Jonker SS, Louey S. Fetal cardiac troponin I levels decline toward birth in sheep. Am J Physiol Heart Circ Physiol 2024; 326:H1538-H1543. [PMID: 38758126 PMCID: PMC11380961 DOI: 10.1152/ajpheart.00224.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2024] [Revised: 05/07/2024] [Accepted: 05/08/2024] [Indexed: 05/18/2024]
Abstract
Elevated cardiac troponin I (cTnI), a myocardial damage biomarker, has been reported in cord blood of neonates delivered vaginally or by cesarean section. Although the neonatal peak likely reflects the physiological adjustment to extrauterine life, a better understanding of serial prepartum changes is required to determine physiological causes of fetal cTnI release. We longitudinally sampled eight healthy lambs (20 days before spontaneous birth to 5 days postnatal), and from three fetuses receiving intravenous IGF-1. Samples were collected into heparin, and the plasma was stored at -80°C for later determination of high-sensitivity (hs) cTnI levels (BeckmanCoulter UniCel DxI Access IA; log transformed detection limit = 0.30, quantification limit = 0.78, 99th percentile = 1.78). Positive and negative control samples were drawn from an adult ewe during a terminal experiment (myocardial ischemia) and similarly assessed. hs-cTnI data were log transformed from ng/L. Log(hs-cTnI) was 1.47 ± 0.30 (means ± SD) at 20 days before birth and declined to 1.02 ± 0.65 in fetuses 12 ± 4 h before birth (P < 0.0001, R2 = 0.7869). Birth stimulated a delayed, transient peak in hs-cTnI (P = 0.0058). Newborn (43 ± 19 min postnatal) levels were 1.39 ± 0.40 (P = 0.0650 vs. fetus on day of birth) and 2.14 ± 0.63 the day after birth (P = 0.0331 vs. newborn). The second day after birth, levels declined to 1.65 ± 0.48 (P = 0.0238 vs. day 1). IGF-1 infusion increased hs-cTnI levels 25-50% over baseline (P = 0.0252, R2 = 0.9938). Baseline adult ewe log(hs-cTnI) was below the limit of detection; 3 h following coronary artery ligation, levels were 3.21. In conclusion, we newly report that fetal hs-cTnI levels decline concomitantly with reduced proliferation of cardiomyocytes toward term.NEW & NOTEWORTHY Serial blood samples were collected from catheterized, normally developing fetal and newborn lambs and high-sensitivity cardiac troponin I (hs-cTnI) levels were assessed, providing unprecedented insight into the physiological processes leading to high levels in the perinatal period. Moderately high levels of hs-cTnI found in the normally developing fetus declined toward term. An elevation to high levels peaked the day after birth, after which hs-cTnI declined again. Stimulation of fetal cardiomyocyte proliferation with IGF-1 also elevated hs-cTnI.
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Affiliation(s)
- Sonnet S Jonker
- Center for Developmental Health, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, Oregon, United States
| | - Samantha Louey
- Center for Developmental Health, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, Oregon, United States
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Hemmingsen D, Moster D, Engdahl B, Klingenberg C. Hearing impairment after asphyxia and neonatal encephalopathy: a Norwegian population-based study. Eur J Pediatr 2024; 183:1163-1172. [PMID: 37991501 PMCID: PMC10950958 DOI: 10.1007/s00431-023-05321-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 10/25/2023] [Accepted: 10/28/2023] [Indexed: 11/23/2023]
Abstract
The purpose of this study is to evaluate the association between perinatal asphyxia, neonatal encephalopathy, and childhood hearing impairment. This is a population-based study including all Norwegian infants born ≥ 36 weeks gestation between 1999 and 2014 and alive at 2 years (n = 866,232). Data was linked from five national health registries with follow-up through 2019. Perinatal asphyxia was defined as need for neonatal intensive care unit (NICU) admission and an Apgar 5-min score of 4-6 (moderate) or 0-3 (severe). We coined infants with seizures and an Apgar 5-min score < 7 as neonatal encephalopathy with seizures. Infants who received therapeutic hypothermia were considered to have moderate-severe hypoxic-ischemic encephalopathy (HIE). The reference group for comparisons were non-admitted infants with Apgar 5-min score ≥ 7. We used logistic regression models and present data as adjusted odds ratios (aORs) with 95% confidence intervals (CI). The aOR for hearing impairment was increased in all infants admitted to NICU: moderate asphyxia aOR 2.2 (95% CI 1.7-2.9), severe asphyxia aOR 5.2 (95% CI 3.6-7.5), neonatal encephalopathy with seizures aOR 7.0 (95% CI 2.6-19.0), and moderate-severe HIE aOR 10.7 (95% CI 5.3-22.0). However, non-admitted infants with Apgar 5-min scores < 7 did not have increased OR of hearing impairment. The aOR for hearing impairment for individual Apgar 5-min scores in NICU infants increased with decreasing Apgar scores and was 13.6 (95% CI 5.9-31.3) when the score was 0. Conclusions: An Apgar 5-min score < 7 in combination with NICU admission is an independent risk factor for hearing impairment. Children with moderate-severe HIE had the highest risk for hearing impairment. What is Known: • Perinatal asphyxia and neonatal encephalopathy are associated with an increased risk of hearing impairment. • The strength of the association, and how other co-morbidities affect the risk of hearing impairment, is poorly defined. What is New: • Among neonates admitted to a neonatal intensive care unit (NICU), decreased Apgar 5-min scores, and increased severity of neonatal encephalopathy, were associated with a gradual rise in risk of hearing impairment. • Neonates with an Apgar 5-min score 7, but without NICU admission, did not have an increased risk of hearing impairment.
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Affiliation(s)
- Dagny Hemmingsen
- Department of Otorhinolaryngology and Head and Neck Surgery, University Hospital of North Norway, N-9038, Tromsø, Norway.
- Paediatric Research Group, Faculty of Health Sciences, UiT-The Arctic University of Norway, Tromsø, Norway.
| | - Dag Moster
- Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway
- Department of Pediatrics, Haukeland University Hospital, Bergen, Norway
| | - Bo Engdahl
- Department of Physical Health and Ageing, Norwegian Institute of Public Health, Oslo, Norway
| | - Claus Klingenberg
- Paediatric Research Group, Faculty of Health Sciences, UiT-The Arctic University of Norway, Tromsø, Norway
- Department of Paediatrics and Adolescence Medicine, University Hospital of North Norway, Tromsø, Norway
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Kazanasmaz H, Akan A, Yalçın Ö, Ölçücü MT, Onar S, Kazanasmaz Ö. Cerebral Tissue Oxygen Saturation Measurements in Perinatal Asphyxia Cases Treated with Therapeutic Hypothermia. Ther Hypothermia Temp Manag 2023; 13:184-190. [PMID: 36920248 DOI: 10.1089/ther.2022.0060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023] Open
Abstract
Cerebral tissue oxygen saturation (CrSO2) measured with near-infrared spectroscopy (NIRS) technology has recently become the subject of several research studies. The aim of this study was to investigate the diagnostic value of CrSO2 measurements in perinatal asphyxia (PA) cases. The study included a patient group of 42 PA cases, who were to be applied with therapeutic hypothermia (TH), and a control group of 42 healthy term newborns. PA cases were determined as moderate or severe encephalopathy (Sarnat score stage II or III) in clinical evaluation. In both groups, left (CrSO2L) and right (CrSO2R) NIRS measurements were taken for 10 minutes on the scalp. The arithmetic mean value of measurements was calculated and compared. The mean measurements were CrSO2R 67.38 ± 9.39 and CrSO2L 66.73 ± 7.76 in the patient group, and CrSO2R 80.28 ± 8.04 and CrSO2L 79.14 ± 8.49 in the control group. The mean CrSO2R and CrSO2L measurements of the patient group were statistically significantly lower than those of the control group (p < 0.001). In the Pearson correlation analysis, a significant correlation was determined in the patient group between cord blood gas pH and CrSO2R (r: 0.539, p < 0.001) and CrSO2L (r: 0.54, p < 0.001). For a cutoff value of CrSO2L ≤ 72%, the positive predictive value was 80 and the negative predictive value was 84.6. For a cutoff value of CrSO2R ≤ 74%, the positive predictive value was 79.5 and the negative predictive value was 82.5. Low CrSO2 measurements obtained with the NIRS method in PA cases to be applied with TH together with cord blood gas parameters can be considered a helpful parameter in diagnosis.
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Affiliation(s)
- Halil Kazanasmaz
- Department of Pediatrics, Harran University Faculty of Medicine, Sanliurfa, Turkey
| | - Abdulsamed Akan
- Department of Pediatrics, Harran University Faculty of Medicine, Sanliurfa, Turkey
| | - Ömer Yalçın
- Department of Pediatrics, Harran University Faculty of Medicine, Sanliurfa, Turkey
| | | | - Selehattin Onar
- Department of Pediatrics, Harran University Faculty of Medicine, Sanliurfa, Turkey
| | - Özlem Kazanasmaz
- Department of Pediatrics Sanliurfa, Sanliurfa Training and Research Hospital, Sanliurfa, Turkey
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Shevtsova Y, Eldarov C, Starodubtseva N, Goryunov K, Chagovets V, Ionov O, Plotnikov E, Silachev D. Identification of Metabolomic Signatures for Ischemic Hypoxic Encephalopathy Using a Neonatal Rat Model. CHILDREN (BASEL, SWITZERLAND) 2023; 10:1693. [PMID: 37892356 PMCID: PMC10605414 DOI: 10.3390/children10101693] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 10/05/2023] [Accepted: 10/07/2023] [Indexed: 10/29/2023]
Abstract
A study was performed to determine early metabolomic markers of ischemic hypoxic encephalopathy (HIE) using a Rice-Vannucci model for newborn rats. Dried blood spots from 7-day-old male and female rat pups, including 10 HIE-affected animals and 16 control animals, were analyzed by liquid chromatography coupled with mass spectrometry (HPLC-MS) in positive and negative ion recording modes. Multivariate statistical analysis revealed two distinct clusters of metabolites in both HPLC-MS modes. Subsequent univariate statistical analysis identified 120 positive and 54 negative molecular ions that exhibited statistically significant change in concentration, with more than a 1.5-fold difference after HIE. In the HIE group, the concentrations of steroid hormones, saturated mono- and triglycerides, and phosphatidylcholines (PCs) were significantly decreased in positive mode. On the contrary, the concentration of unsaturated PCs was increased in the HIE group. Among negatively charged molecular ions, the greatest variations were found in the categories of phosphatidylcholines, phosphatidylinositols, and triglycerides. The major metabolic pathways associated with changed metabolites were analyzed for both modes. Metabolic pathways such as steroid biosynthesis and metabolism fatty acids were most affected. These results underscored the central role of glycerophospholipid metabolism in triggering systemic responses in HIE. Therefore, lipid biomarkers' evaluation by targeted HPLC-MS research could be a promising approach for the early diagnosis of HIE.
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Affiliation(s)
- Yulia Shevtsova
- V.I. Kulakov National Medical Research Center for Obstetrics Gynecology and Perinatology, Ministry of Healthcare of Russian Federation, 117997 Moscow, Russia; (Y.S.); (C.E.); (N.S.); (K.G.); (V.C.); (O.I.); (E.P.)
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia
| | - Chupalav Eldarov
- V.I. Kulakov National Medical Research Center for Obstetrics Gynecology and Perinatology, Ministry of Healthcare of Russian Federation, 117997 Moscow, Russia; (Y.S.); (C.E.); (N.S.); (K.G.); (V.C.); (O.I.); (E.P.)
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia
| | - Natalia Starodubtseva
- V.I. Kulakov National Medical Research Center for Obstetrics Gynecology and Perinatology, Ministry of Healthcare of Russian Federation, 117997 Moscow, Russia; (Y.S.); (C.E.); (N.S.); (K.G.); (V.C.); (O.I.); (E.P.)
| | - Kirill Goryunov
- V.I. Kulakov National Medical Research Center for Obstetrics Gynecology and Perinatology, Ministry of Healthcare of Russian Federation, 117997 Moscow, Russia; (Y.S.); (C.E.); (N.S.); (K.G.); (V.C.); (O.I.); (E.P.)
| | - Vitaliy Chagovets
- V.I. Kulakov National Medical Research Center for Obstetrics Gynecology and Perinatology, Ministry of Healthcare of Russian Federation, 117997 Moscow, Russia; (Y.S.); (C.E.); (N.S.); (K.G.); (V.C.); (O.I.); (E.P.)
| | - Oleg Ionov
- V.I. Kulakov National Medical Research Center for Obstetrics Gynecology and Perinatology, Ministry of Healthcare of Russian Federation, 117997 Moscow, Russia; (Y.S.); (C.E.); (N.S.); (K.G.); (V.C.); (O.I.); (E.P.)
| | - Egor Plotnikov
- V.I. Kulakov National Medical Research Center for Obstetrics Gynecology and Perinatology, Ministry of Healthcare of Russian Federation, 117997 Moscow, Russia; (Y.S.); (C.E.); (N.S.); (K.G.); (V.C.); (O.I.); (E.P.)
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia
| | - Denis Silachev
- V.I. Kulakov National Medical Research Center for Obstetrics Gynecology and Perinatology, Ministry of Healthcare of Russian Federation, 117997 Moscow, Russia; (Y.S.); (C.E.); (N.S.); (K.G.); (V.C.); (O.I.); (E.P.)
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia
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Caramelo I, Coelho M, Rosado M, Cardoso CMP, Dinis A, Duarte CB, Grãos M, Manadas B. Biomarkers of hypoxic-ischemic encephalopathy: a systematic review. World J Pediatr 2023; 19:505-548. [PMID: 37084165 PMCID: PMC10199106 DOI: 10.1007/s12519-023-00698-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 01/31/2023] [Indexed: 04/22/2023]
Abstract
BACKGROUND Current diagnostic criteria for hypoxic-ischemic encephalopathy in the early hours lack objective measurement tools. Therefore, this systematic review aims to identify putative molecules that can be used in diagnosis in daily clinical practice (PROSPERO ID: CRD42021272610). DATA SOURCES Searches were performed in PubMed, Web of Science, and Science Direct databases until November 2020. English original papers analyzing samples from newborns > 36 weeks that met at least two American College of Obstetricians and Gynecologists diagnostic criteria and/or imaging evidence of cerebral damage were included. Bias was assessed by the Newcastle-Ottawa Scale. The search and data extraction were verified by two authors separately. RESULTS From 373 papers, 30 met the inclusion criteria. Data from samples collected in the first 72 hours were extracted, and increased serum levels of neuron-specific enolase and S100-calcium-binding protein-B were associated with a worse prognosis in newborns that suffered an episode of perinatal asphyxia. In addition, the levels of glial fibrillary acidic protein, ubiquitin carboxyl terminal hydrolase isozyme-L1, glutamic pyruvic transaminase-2, lactate, and glucose were elevated in newborns diagnosed with hypoxic-ischemic encephalopathy. Moreover, pathway analysis revealed insulin-like growth factor signaling and alanine, aspartate and glutamate metabolism to be involved in the early molecular response to insult. CONCLUSIONS Neuron-specific enolase and S100-calcium-binding protein-B are potential biomarkers, since they are correlated with an unfavorable outcome of hypoxic-ischemic encephalopathy newborns. However, more studies are required to determine the sensitivity and specificity of this approach to be validated for clinical practice.
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Affiliation(s)
- Inês Caramelo
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504, Coimbra, Portugal
- PhD Programme in Experimental Biology and Biomedicine, Institute for Interdisciplinary Research (IIIUC), University of Coimbra, Casa Costa Alemão, 3030-789, Coimbra, Portugal
| | - Margarida Coelho
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504, Coimbra, Portugal
- Chemistry Department, Faculty of Sciences and Technology, University of Coimbra, 3004-535, Coimbra, Portugal
| | - Miguel Rosado
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504, Coimbra, Portugal
- PhD Programme in Experimental Biology and Biomedicine, Institute for Interdisciplinary Research (IIIUC), University of Coimbra, Casa Costa Alemão, 3030-789, Coimbra, Portugal
| | | | - Alexandra Dinis
- Pediatric Intensive Care Unit, Hospital Pediátrico, Centro Hospitalar E Universitário de Coimbra, 3000-075, Coimbra, Portugal
| | - Carlos B Duarte
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504, Coimbra, Portugal
- Department of Life Sciences, University of Coimbra, 3001-401, Coimbra, Portugal
| | - Mário Grãos
- Biocant, Technology Transfer Association, 3060-197, Cantanhede, Portugal
| | - Bruno Manadas
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504, Coimbra, Portugal.
- Institute for Interdisciplinary Research, University of Coimbra (IIIUC), 3030-789, Coimbra, Portugal.
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Starodubtseva NL, Eldarov C, Kirtbaya AR, Balashova EN, Gryzunova AS, Ionov OV, Zubkov VV, Silachev DN. Recent advances in diagnostics of neonatal hypoxic ischemic encephalopathy. BULLETIN OF RUSSIAN STATE MEDICAL UNIVERSITY 2022. [DOI: 10.24075/brsmu.2022.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The prognosis in neonatal hypoxic ischemic encephalopathy (HIE) depends on early differential diagnosis for justified administration of emergency therapeutic hypothermia. The moment of therapy initiation directly affects the long-term neurological outcome: the earlier the commencement, the better the prognosis. This review analyzes recent advances in systems biology that facilitate early differential diagnosis of HIE as a pivotal complement to clinical indicators. We discuss the possibilities of clinical translation for proteomic, metabolomic and extracellular vesicle patterns characteristic of HIE and correlations with severity and prognosis. Identification and use of selective biomarkers of brain damage in neonates during the first hours of life is hindered by systemic effects of hypoxia. Chromatography– mass spectrometry blood tests allow analyzing hundreds and thousands of metabolites in a small biological sample to identify characteristic signatures of brain damage. Clinical use of advanced analytical techniques will facilitate the accurate and timely diagnosis of HIE for enhanced management.
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Affiliation(s)
- NL Starodubtseva
- Kulakov National Medical Research Center for Obstetrics, Gynecology and Perinatology, Moscow, Russia
| | - ChM Eldarov
- Kulakov National Medical Research Center for Obstetrics, Gynecology and Perinatology, Moscow, Russia
| | - AR Kirtbaya
- Kulakov National Medical Research Center for Obstetrics, Gynecology and Perinatology, Moscow, Russia
| | - EN Balashova
- Kulakov National Medical Research Center for Obstetrics, Gynecology and Perinatology, Moscow, Russia
| | - AS Gryzunova
- Kulakov National Medical Research Center for Obstetrics, Gynecology and Perinatology, Moscow, Russia
| | - OV Ionov
- Kulakov National Medical Research Center for Obstetrics, Gynecology and Perinatology, Moscow, Russia
| | - VV Zubkov
- Kulakov National Medical Research Center for Obstetrics, Gynecology and Perinatology, Moscow, Russia
| | - DN Silachev
- Kulakov National Medical Research Center for Obstetrics, Gynecology and Perinatology, Moscow, Russia
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Amelio GS, Provitera L, Raffaeli G, Amodeo I, Gulden S, Cortesi V, Manzoni F, Pesenti N, Tripodi M, Pravatà V, Lonati C, Cervellini G, Mosca F, Cavallaro G. Proinflammatory Endothelial Phenotype in Very Preterm Infants: A Pilot Study. Biomedicines 2022; 10:biomedicines10051185. [PMID: 35625922 PMCID: PMC9138391 DOI: 10.3390/biomedicines10051185] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 05/17/2022] [Accepted: 05/18/2022] [Indexed: 02/04/2023] Open
Abstract
Very preterm infants are exposed to prenatal inflammatory processes and early postnatal hemodynamic and respiratory complications, but limited data are available about the endothelial effect of these conditions. The present pilot study investigates the perinatal endothelial phenotype in very preterm infants (VPIs) and explores its predictive value on neonatal mortality and hemodynamic and respiratory complications. Angiopoietin 1 (Ang-1), Ang-2, E-selectin, vascular adhesion molecule 1 (VCAM-1), tissue factor (TF), and endothelin 1 (ET-1) concentrations were tested in first (T1), 3rd (T2), and 7–10th (T3) day of life in 20 VPIs using Luminex technology and compared with 14 healthy full-term infants (FTIs). Compared to FTIs, VPIs had lower Ang-1 at T1 and T2; higher Ang-2 at T1, T2, and T3; higher Ang-2/Ang-1 ratio at T1, T2, and T3; lower E-selectin at T1, T2, and T3; higher VCAM-1 at T1; higher TF at T2. No differences in concentrations were found in neonatal deaths. VPIs with hemodynamic or respiratory complications had higher Ang-2 at T3. Perinatal low Ang-1 and high Ang-2 associated with high VCAM-1 and TF in VPIs suggest a proinflammatory endothelial phenotype, resulting from the synergy of a pathological prenatal inheritance and a premature extrauterine transition.
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Affiliation(s)
- Giacomo S. Amelio
- Neonatal Intensive Care Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy; (G.S.A.); (L.P.); (G.R.); (I.A.); (S.G.); (V.C.); (F.M.); (N.P.); (M.T.); (V.P.); (G.C.); (F.M.)
| | - Livia Provitera
- Neonatal Intensive Care Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy; (G.S.A.); (L.P.); (G.R.); (I.A.); (S.G.); (V.C.); (F.M.); (N.P.); (M.T.); (V.P.); (G.C.); (F.M.)
| | - Genny Raffaeli
- Neonatal Intensive Care Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy; (G.S.A.); (L.P.); (G.R.); (I.A.); (S.G.); (V.C.); (F.M.); (N.P.); (M.T.); (V.P.); (G.C.); (F.M.)
- Department of Clinical Sciences and Community Health, Università degli Studi di Milano, 20122 Milan, Italy
| | - Ilaria Amodeo
- Neonatal Intensive Care Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy; (G.S.A.); (L.P.); (G.R.); (I.A.); (S.G.); (V.C.); (F.M.); (N.P.); (M.T.); (V.P.); (G.C.); (F.M.)
| | - Silvia Gulden
- Neonatal Intensive Care Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy; (G.S.A.); (L.P.); (G.R.); (I.A.); (S.G.); (V.C.); (F.M.); (N.P.); (M.T.); (V.P.); (G.C.); (F.M.)
| | - Valeria Cortesi
- Neonatal Intensive Care Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy; (G.S.A.); (L.P.); (G.R.); (I.A.); (S.G.); (V.C.); (F.M.); (N.P.); (M.T.); (V.P.); (G.C.); (F.M.)
- Department of Clinical Sciences and Community Health, Università degli Studi di Milano, 20122 Milan, Italy
| | - Francesca Manzoni
- Neonatal Intensive Care Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy; (G.S.A.); (L.P.); (G.R.); (I.A.); (S.G.); (V.C.); (F.M.); (N.P.); (M.T.); (V.P.); (G.C.); (F.M.)
- Department of Clinical Sciences and Community Health, Università degli Studi di Milano, 20122 Milan, Italy
| | - Nicola Pesenti
- Neonatal Intensive Care Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy; (G.S.A.); (L.P.); (G.R.); (I.A.); (S.G.); (V.C.); (F.M.); (N.P.); (M.T.); (V.P.); (G.C.); (F.M.)
- Department of Statistics and Quantitative Methods, Division of Biostatistics, Epidemiology, and Public Health, University of Milano-Bicocca, 20126 Milan, Italy
| | - Matteo Tripodi
- Neonatal Intensive Care Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy; (G.S.A.); (L.P.); (G.R.); (I.A.); (S.G.); (V.C.); (F.M.); (N.P.); (M.T.); (V.P.); (G.C.); (F.M.)
| | - Valentina Pravatà
- Neonatal Intensive Care Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy; (G.S.A.); (L.P.); (G.R.); (I.A.); (S.G.); (V.C.); (F.M.); (N.P.); (M.T.); (V.P.); (G.C.); (F.M.)
| | - Caterina Lonati
- Center for Preclinical Investigation, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy;
| | - Gaia Cervellini
- Neonatal Intensive Care Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy; (G.S.A.); (L.P.); (G.R.); (I.A.); (S.G.); (V.C.); (F.M.); (N.P.); (M.T.); (V.P.); (G.C.); (F.M.)
- Department of Clinical Sciences and Community Health, Università degli Studi di Milano, 20122 Milan, Italy
| | - Fabio Mosca
- Neonatal Intensive Care Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy; (G.S.A.); (L.P.); (G.R.); (I.A.); (S.G.); (V.C.); (F.M.); (N.P.); (M.T.); (V.P.); (G.C.); (F.M.)
- Department of Clinical Sciences and Community Health, Università degli Studi di Milano, 20122 Milan, Italy
| | - Giacomo Cavallaro
- Neonatal Intensive Care Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy; (G.S.A.); (L.P.); (G.R.); (I.A.); (S.G.); (V.C.); (F.M.); (N.P.); (M.T.); (V.P.); (G.C.); (F.M.)
- Correspondence: ; Tel.: +39-(02)-55032234; Fax: +39-(02)-55032217
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9
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Wassink G, Harrison S, Dhillon S, Bennet L, Gunn AJ. Prognostic neurobiomarkers in neonatal encephalopathy. Dev Neurosci 2022; 44:331-343. [PMID: 35168240 DOI: 10.1159/000522617] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Accepted: 02/09/2022] [Indexed: 11/19/2022] Open
Abstract
Therapeutic hypothermia is now standard-care for infants with moderate-severe neonatal encephalopathy (NE), and improves brain damage on neuroimaging, and neurodevelopmental outcomes. Critically, for effective neuroprotection, hypothermia should be started within 6 h from birth. There is compelling evidence to suggest that a proportion of infants with mild NE have material risk of developing brain damage and poor outcomes. This cohort is increasingly being offered therapeutic hypothermia, despite lack of trial evidence for its benefit. In current practice, infants need to be diagnosed within 6 h of birth for therapeutic treatment, compared to retrospective NE grading in the pre-hypothermia era. This presents challenges as NE is a dynamic brain disorder that can worsen or resolve over time. Neurological symptoms of NE can be difficult to discern in the first few hours after birth, and confounded by analgesics and anesthetic treatment. Using current enrolment criteria, a significant number of infants with NE that would benefit from hypothermia are not treated, and vice versa, infants are receiving mild hypothermia when its benefit will be limited. Better biomarkers are needed to further improve management and treatment of these neonates. In the present review, we examine the latest research, and highlight a central limitation of most current biomarkers: that their predictive value is consistently greatest after most neuroprotective therapies are no longer effective.
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Affiliation(s)
- Guido Wassink
- The Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Steven Harrison
- The Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Simerdeep Dhillon
- The Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Laura Bennet
- The Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Alistair Jan Gunn
- The Department of Physiology, University of Auckland, Auckland, New Zealand
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10
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Xu ZE, Mbugi J, Hu Y, Yue W, Hua Z, Wei H. Serum troponin I: a potential biomarker of hypoxic-ischemic encephalopathy in term newborns. Childs Nerv Syst 2022; 38:295-301. [PMID: 34609613 DOI: 10.1007/s00381-021-05368-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 09/18/2021] [Indexed: 11/27/2022]
Abstract
OBJECTIVE This study was intended to evaluate the predictive values of serum procalcitonin (PCT), lactate, creatine kinase (CK-MB), and troponin I on the diagnosis and staging of neonatal hypoxic-ischemic encephalopathy (HIE). MATERIALS AND METHODS We retrospectively retrieved data from electronic medical records at our children's hospital, and we included all term newborns admitted between December 2018 and June 2020 with features of perinatal asphyxia. Receiver operating characteristic (ROC) curve and area under the curve (AUC) were used to measure and evaluate the predictive values of biomarkers. p values < 0.05 were set as statistical significance. RESULTS A total of 201 neonates were included. They were grouped as control (n = 40), mild HIE (n = 105), moderate HIE (n = 36), and severe HIE (n = 20). Serum lactate, PCT, CK-MB, and troponin I levels in severe hypoxic-ischemic brain injury group were significantly higher than those in mild to moderate hypoxic-ischemic brain injury group and control group (p < 0.05). Based on ROC and AUC analysis, troponin I showed highest predictive ability with AUC of 0.904, and sensitivity and specificity of 95.00% and 87.50% respectively. CONCLUSION Serum troponin I has a good predictive value for neonatal hypoxic-ischemic encephalopathy after perinatal asphyxia.
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Affiliation(s)
- Zhen-E Xu
- Department of Neonatology, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Juma Mbugi
- Department of Neonatology, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Ya Hu
- Department of Neonatology, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Weihong Yue
- Department of Neonatology, Children's Hospital of Chongqing Medical University, Chongqing, China.,China International Science and Technology Cooperation base of Child development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Chongqing, China
| | - Ziyu Hua
- Department of Neonatology, Children's Hospital of Chongqing Medical University, Chongqing, China.,China International Science and Technology Cooperation base of Child development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Chongqing, China
| | - Hong Wei
- Department of Neonatology, Children's Hospital of Chongqing Medical University, Chongqing, China. .,Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, China. .,National Clinical Research Center for Child Health and Disorders, Chongqing, China.
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11
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Jayasinghe D, Wilcox L, Schoonakker B. The safety of passive hypothermia during assessment for hypoxic ischaemic encephalopathy. Early Hum Dev 2021; 157:105351. [PMID: 33836488 DOI: 10.1016/j.earlhumdev.2021.105351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 03/03/2021] [Accepted: 03/09/2021] [Indexed: 11/20/2022]
Abstract
INTRODUCTION Hypoxic ischaemic encephalopathy (HIE) is poorly predicted by markers of hypoxic ischaemic (HI) delivery. Repeated examination of infants with HI markers facilitates diagnostic certainty of HIE severity. When infants with HIE are nursed at incubator ambient air-temperature set to achieve normothermia, there is sometimes associated hyperthermia, a predictor of poor outcome. An alternative is to nurse infants without external heat (passive hypothermia, PH). We report a retrospective cohort-study to determine the safety of PH during the assessment of infant eligibility for therapeutic hypothermia (TH). METHODS Inborn infants of gestational age ≥36 weeks, less than 6 h of age, with evidence of HI delivery were admitted for assessment for HIE. Infants were nursed undressed in an incubator treated with PH and underwent serial neurological examinations to determine eligibility for TH. Body temperature was monitored but no targeted temperature was set. Safety outcomes during PH were: minimum and maximum temperatures, minimum and maximum glucose recordings, time to onset of TH, platelet count, maximum and minimum blood glucose concentration. RESULTS 26 infants with median gestational age of 39 weeks, median birth weight of 3.30 kg underwent PH for a median duration of 4 h 19 min. During PH the median minimum and maximum temperatures recorded were 35.9 °C and 36.7 °C, the median minimum glucose was 4.6 mmol/L. Fourteen infants were eligible for TH and target temperature was achieved at median age of 4 h. CONCLUSION PH is not associated with adverse safety outcomes and without delaying achieving TH target-temperature.
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Affiliation(s)
| | - Lydia Wilcox
- Nottingham University Hospitals NHS Trust, Nottingham, UK
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12
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The physiology of intrapartum fetal compromise at term. Am J Obstet Gynecol 2020; 222:17-26. [PMID: 31351061 DOI: 10.1016/j.ajog.2019.07.032] [Citation(s) in RCA: 91] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 06/26/2019] [Accepted: 07/18/2019] [Indexed: 12/11/2022]
Abstract
Uterine contractions in labor result in a 60% reduction in uteroplacental perfusion, causing transient fetal and placental hypoxia. A healthy term fetus with a normally developed placenta is able to accommodate this transient hypoxia by activation of the peripheral chemoreflex, resulting in a reduction in oxygen consumption and a centralization of oxygenated blood to critical organs, namely the heart, brain, and adrenals. Providing there is adequate time for placental and fetal reperfusion between contractions, these fetuses will be able to withstand prolonged periods of intermittent hypoxia and avoid severe hypoxic injury. However, there exists a cohort of fetuses in whom abnormal placental development in the first half of pregnancy results in failure of endovascular invasion of the spiral arteries by the cytotrophoblastic cells and inadequate placental angiogenesis. This produces a high-resistance, low-flow circulation predisposing to hypoperfusion, hypoxia, reperfusion injury, and oxidative stress within the placenta. Furthermore, this renders the placenta susceptible to fluctuations and reduction in uteroplacental perfusion in response to external compression and stimuli (as occurs in labor), further reducing fetal capillary perfusion, placing the fetus at risk of inadequate gas/nutrient exchange. This placental dysfunction predisposes the fetus to intrapartum fetal compromise. In the absence of a rare catastrophic event, intrapartum fetal compromise occurs as a gradual process when there is an inability of the fetal heart to respond to the peripheral chemoreflex to maintain cardiac output. This may arise as a consequence of placental dysfunction reducing pre-labor myocardial glycogen stores necessary for anaerobic metabolism or due to an inadequate placental perfusion between contractions to restore fetal oxygen and nutrient exchange. If the hypoxic insult is severe enough and long enough, profound multiorgan injury and even death may occur. This review provides a detailed synopsis of the events that can result in placental dysfunction, how this may predispose to intrapartum fetal hypoxia, and what protective mechanisms are in place to avoid hypoxic injury.
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13
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Van Anh TN, Hao TK, Chi NTD, Son NH. Predictions of Hypoxic-Ischemic Encephalopathy by Umbilical Cord Blood Lactate in Newborns with Birth Asphyxia. Open Access Maced J Med Sci 2019; 7:3564-3567. [PMID: 32010377 PMCID: PMC6986534 DOI: 10.3889/oamjms.2019.581] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Revised: 09/04/2019] [Accepted: 09/05/2019] [Indexed: 12/02/2022] Open
Abstract
AIM: The aim of the study was to investigate the role of umbilical cord blood lactate as early predictors of hypoxic ischemic encephalopathy in newborns with perinatal asphyxia and to evaluate their sensitivity and specificity for the early identification of hypoxic ischemic encephalopathy infants. METHODS: We performed a descriptive cross sectional study between April 2014 and April 2015 at Hue Central Hospital, Vietnam. 41 asphyxia newborns (Apgar score ≤ 7) were included in the study. Umbilical cord blood is sampled for lactate analysis. RESULTS: Umbilical cord blood lactate levels were significantly higher among infants born with HIE (mean 8.72 ± 1.75, range 5.12 – 11.96) compared to that with asphyxic infants without HIE (mean 6.86 ± 1.33, range 4.74 – 10.30), p = 0.00. With the optimal cutoff point for umbilical cord blood lactate level of 8.12 mmol/l to susspected of HIE (area under the curve 0.799) had a sensitivity 73.7% (95% CI 48.8-90.9), specificity 86.4% (95% CI 65.1-97.1). CONCLUSION: Umbilical cord blood lactate could be used as early predictors in diagnosis of hypoxic ischemic encephalopathy in newborns with asphyxia.
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Affiliation(s)
- Ton Nu Van Anh
- Pediatric Department, Hue University of Medicine and Pharmacy, Hue University, Hue, Vietnam
| | - Tran Kiem Hao
- Pediatric Center, Hue Central Hospital, Hue, Vietnam
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14
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Murray DM. Biomarkers in neonatal hypoxic-ischemic encephalopathy-Review of the literature to date and future directions for research. HANDBOOK OF CLINICAL NEUROLOGY 2019; 162:281-293. [PMID: 31324315 DOI: 10.1016/b978-0-444-64029-1.00013-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The widespread introduction of therapeutic hypothermia as a standard of care in hypoxic-ischemic encephalopathy (HIE) has brought increasing pressure on clinicians to make an early and accurate assessment of the degree of hypoxic injury (HI) that has occurred and the severity of the encephalopathy that will ensue. No single blood-based marker is currently robust enough to detect significant HI or predict outcome. However, research in the field has been active in the last 10 years and we know that HIE is associated with predictable alterations in the expression of a number of inflammatory proteins, neuron-specific proteins, metabolite pathways, and microRNA. These alterations evolve quickly over the first hours and days of life. Predictive power varies depending on the timing of measurement of the biomarker, the sample type, and the case mix of the cohort examined. Combining clinical data with biochemical measurements is currently the most likely path toward improved detection and prediction of outcome in neonatal HIE.
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Affiliation(s)
- Deirdre M Murray
- Department of Paediatrics and Child Health, University College Cork, Cork, Ireland.
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15
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Karlén J, Karlsson M, Eliasson H, Bonamy AKE, Halvorsen CP. Cardiac Troponin T in Healthy Full-Term Infants. Pediatr Cardiol 2019; 40:1645-1654. [PMID: 31489446 PMCID: PMC6848050 DOI: 10.1007/s00246-019-02199-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 08/23/2019] [Indexed: 11/26/2022]
Abstract
In this prospective cohort study of healthy full-term infants, we hypothesized that high-sensitivity cardiac troponin T (hs-cTnT) would be elevated in cord blood, compared with adult reference values, and that it would further increase over the first days of age. Cardiac troponin T has been shown to be significantly increased in healthy full-term newborns compared with adult reference values, but there is no established reference range. Most studies of cTnT in newborns have been performed before the introduction of high-sensitivity cTnT (hs-cTnT) assay. We conducted a study including 158 full-term newborns, at Stockholm South General Hospital. High-sensitivity cTnT was analyzed in umbilical cord blood and at 2-5 days of age. Median hs-cTnT (interquartile range) in cord blood was 34(26-44) ng/L; 99th percentile 88 ng/L. Median hs-cTnT at 2-5 days of age was 92(54-158) ng/L; 99th percentile 664 ng/L. We conclude that hs-cTnT is elevated in cord blood in healthy, full-term newborn infants compared with adult reference values, and that it increases significantly during the first days of life. Our findings further underline the need of caution when using hs-cTnT as a measurement of cardiac impact in newborns.
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Affiliation(s)
- Jonna Karlén
- Department of Clinical Science and Education, Södersjukhuset, Karolinska Institutet, Sjukhusbacken 10, 118 83, Stockholm, Sweden.
- Neonatal Unit at Sachs' Children's and Youth Hospital, Hjalmar Cederströms gata 14, 118 61, Stockholm, Sweden.
| | - Mathias Karlsson
- Department of Medical Sciences, Biomedical Structure and Function, Uppsala University, 751 85, Uppsala, Sweden
| | - Håkan Eliasson
- Department of Women's and Children's Health, Karolinska Institutet, Widerströmska huset, Tomtebodavägen 18A, 171 77, Stockholm, Sweden
- Pediatric Cardiology Department, Astrid Lindgrens Children's Hospital, Eugeniavägen 23, 171 64, Solna, Sweden
| | - Anna-Karin Edstedt Bonamy
- Neonatal Unit at Sachs' Children's and Youth Hospital, Hjalmar Cederströms gata 14, 118 61, Stockholm, Sweden
- Clinical Epidemiology Division, Karolinska Institutet, Karolinska vägen, 171 76, Stockholm, Sweden
| | - Cecilia Pegelow Halvorsen
- Department of Clinical Science and Education, Södersjukhuset, Karolinska Institutet, Sjukhusbacken 10, 118 83, Stockholm, Sweden
- Neonatal Unit at Sachs' Children's and Youth Hospital, Hjalmar Cederströms gata 14, 118 61, Stockholm, Sweden
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16
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Lear CA, Wassink G, Westgate JA, Nijhuis JG, Ugwumadu A, Galinsky R, Bennet L, Gunn AJ. The peripheral chemoreflex: indefatigable guardian of fetal physiological adaptation to labour. J Physiol 2018; 596:5611-5623. [PMID: 29604081 DOI: 10.1113/jp274937] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 03/29/2018] [Indexed: 01/10/2023] Open
Abstract
The fetus is consistently exposed to repeated periods of impaired oxygen (hypoxaemia) and nutrient supply in labour. This is balanced by the healthy fetus's remarkable anaerobic tolerance and impressive ability to mount protective adaptations to hypoxaemia. The most important mediator of fetal adaptations to brief repeated hypoxaemia is the peripheral chemoreflex, a rapid reflex response to acute falls in arterial oxygen tension. The overwhelming majority of fetuses are able to respond to repeated uterine contractions without developing hypotension or hypoxic-ischaemic injury. In contrast, fetuses who are either exposed to severe hypoxaemia, for example during uterine hyperstimulation, or enter labour with reduced anaerobic reserve (e.g. as shown by severe fetal growth restriction) are at increased risk of developing intermittent hypotension and cerebral hypoperfusion. It is remarkable to note that when fetuses develop hypotension during such repeated severe hypoxaemia, it is not mediated by impaired reflex adaptation, but by failure to maintain combined ventricular output, likely due to a combination of exhaustion of myocardial glycogen and evolving myocardial injury. The chemoreflex is suppressed by relatively long periods of severe hypoxaemia of 1.5-2 min, longer than the typical contraction. Even in this setting, the peripheral chemoreflex is consistently reactivated between contractions. These findings demonstrate that the peripheral chemoreflex is an indefatigable guardian of fetal adaptation to labour.
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Affiliation(s)
- Christopher A Lear
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Guido Wassink
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Jenny A Westgate
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand.,Department of Obstetrics and Gynaecology, The University of Auckland, Auckland, New Zealand
| | - Jan G Nijhuis
- Department of Obstetrics and Gynaecology, GROW School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht, the Netherlands
| | - Austin Ugwumadu
- Department of Obstetrics and Gynaecology, St George's, University of London, London, UK
| | - Robert Galinsky
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Laura Bennet
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Alistair J Gunn
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
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