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Rieger MG, Tallon CM, Perkins DR, Smith KJ, Stembridge M, Piombo S, Radom-Aizik S, Cooper DM, Ainslie PN, McManus AM. Cardiopulmonary and cerebrovascular acclimatization in children and adults at 3800 m. J Physiol 2022; 600:4849-4863. [PMID: 36165275 DOI: 10.1113/jp283419] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 09/20/2022] [Indexed: 12/24/2022] Open
Abstract
Maturational differences exist in cardiopulmonary and cerebrovascular function at sea-level, but the impact of maturation on acclimatization responses to high altitude is unknown. Ten children (9.8 ± 2.5 years) and 10 adults (34.7 ± 7.1 years) were assessed at sea-level (BL), 3000 m and twice over 4 days at 3800 m (B1, B4). Measurements included minute ventilation ( V ̇ E ${\dot{V}}_{\rm{E}}$ ), end-tidal partial pressures of oxygen ( P ETO 2 ${P}_{{\rm{ETO}}_{\rm{2}}}$ ) and carbon dioxide, echocardiographic assessment of pulmonary artery systolic pressure (PASP) and stroke volume (SV) and ultrasound assessment of blood flow through the internal carotid and vertebral arteries was performed to calculate global cerebral blood flow (gCBF). At 3000 m, V ̇ E ${\dot{V}}_{\rm{E}}$ was increased from BL by 19.6 ± 19.1% (P = 0.031) in children, but not in adults (P = 0.835); SV was reduced in children (-11 ± 13%, P = 0.020) but not adults (P = 0.827), which was compensated for by a larger increase in heart rate in children (+26 beats min-1 vs. +13 beats min-1 , P = 0.019). Between B1 and B4, adults increased V ̇ E ${\dot{V}}_{\rm{E}}$ by 38.5 ± 34.7% (P = 0.006), while V ̇ E ${\dot{V}}_{\rm{E}}$ did not increase further in children. The rise in PASP was not different between groups; however, ∆PASP from BL was related to ∆ P ETO 2 ${P}_{{\rm{ETO}}_{\rm{2}}}$ in adults (R2 = 0.288, P = 0.022), but not children. At BL, gCBF was 43% higher in children than adults (P = 0.017), and this difference was maintained at high altitude, with a similar pattern and magnitude of change in gCBF between groups (P = 0.845). Despite V ̇ E ${\dot{V}}_{\rm{E}}$ increasing in children but not adults at a lower altitude, the pulmonary vascular and cerebrovascular responses to prolonged hypoxia are similar between children and adults. KEY POINTS: Children have different ventilatory and metabolic requirements from adults, which may present differently in the pulmonary and cerebral vasculature upon ascent to high altitude. Children (ages 7-14) and adults (ages 23-44) were brought from sea level to high altitude (3000 to 3800 m) and changes in ventilation, pulmonary artery systolic pressure (PASP) and cerebral blood flow (CBF) were assessed over 1 week. Significant increases in ventilation and decreases in left ventricle stroke volume were observed at a lower altitude in children than adults. PASP and CBF increased by a similar relative amount between children and adults at 3800 m. These results help us better understand age-related differences in compensatory responses to prolonged hypoxia in children, despite similar changes in pulmonary artery pressure and CBF between children and adults.
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Affiliation(s)
- M G Rieger
- Centre for Heart, Lung & Vascular Health, University of British Columbia, Kelowna, British Columbia, Canada
| | - C M Tallon
- Centre for Heart, Lung & Vascular Health, University of British Columbia, Kelowna, British Columbia, Canada
| | - D R Perkins
- Cardiff School of Sport & Health Sciences, Cardiff Metropolitan University, Cardiff, UK.,Youth Physical Development Centre, Cardiff School of Sport & Health Sciences, Cardiff Metropolitan University, Cardiff, UK
| | - K J Smith
- Cerebrovascular Health, Exercise, and Environmental Research Sciences, University of Victoria, Victoria, British Columbia, Canada
| | - M Stembridge
- Cardiff School of Sport & Health Sciences, Cardiff Metropolitan University, Cardiff, UK.,Youth Physical Development Centre, Cardiff School of Sport & Health Sciences, Cardiff Metropolitan University, Cardiff, UK
| | - S Piombo
- Pediatric Exercise and Genomics Research Center, University of California Irvine School of Medicine, Irvine, CA, USA
| | - S Radom-Aizik
- Pediatric Exercise and Genomics Research Center, University of California Irvine School of Medicine, Irvine, CA, USA
| | - D M Cooper
- Pediatric Exercise and Genomics Research Center, University of California Irvine School of Medicine, Irvine, CA, USA
| | - P N Ainslie
- Centre for Heart, Lung & Vascular Health, University of British Columbia, Kelowna, British Columbia, Canada
| | - A M McManus
- Centre for Heart, Lung & Vascular Health, University of British Columbia, Kelowna, British Columbia, Canada
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Abstract
BACKGROUND Left ventricular noncompaction (LVNC) is the third most common pediatric cardiomyopathy characterized by a thinned myocardium and prominent trabeculations. Next-generation genetic testing has led to a rapid increase in the number of genes reported to be associated with LVNC, but we still have little understanding of its pathogenesis. We sought to grade the strength of the gene-disease relationship for all genes reported to be associated with LVNC and identify molecular pathways that could be implicated. METHODS Following a systematic PubMed review, all genes identified with LVNC were graded using a validated, semi-quantitative system based on all published genetic and experimental evidence created by the Clinical Genome Resource (ClinGen). Genetic pathway analysis identified molecular processes and pathways associated with LVNC. RESULTS We identified 189 genes associated with LVNC: 11 (6%) were classified as definitive, 21 (11%) were classified as moderate, and 140 (74%) were classified as limited, but 17 (9%) were classified as no evidence. Of the 32 genes classified as definitive or moderate, the most common gene functions were sarcomere function (n=11; 34%), transcriptional/translational regulator (n=6; 19%), mitochondrial function (n=3; 9%), and cytoskeletal protein (n=3; 9%). Furthermore, 18 (56%) genes were implicated in noncardiac syndromic presentations. Lastly, 3 genetic pathways (cardiomyocyte differentiation via BMP receptors, factors promoting cardiogenesis in vertebrates, and Notch signaling) were found to be unique to LVNC and not overlap with pathways identified in dilated cardiomyopathy and hypertrophic cardiomyopathy. CONCLUSIONS LVNC is a genetically heterogeneous cardiomyopathy. Distinct from dilated or hypertrophic cardiomyopathies, LVNC appears to arise from abnormal developmental processes.
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Affiliation(s)
- Pakdee Rojanasopondist
- Division of Pediatric Cardiology, Department of Pediatrics (P.R., L.N., S.P., C.K.L.P.), NYU Grossman School of Medicine, NY
| | - Leigh Nesheiwat
- Division of Pediatric Cardiology, Department of Pediatrics (P.R., L.N., S.P., C.K.L.P.), NYU Grossman School of Medicine, NY
| | - Sebastian Piombo
- Division of Pediatric Cardiology, Department of Pediatrics (P.R., L.N., S.P., C.K.L.P.), NYU Grossman School of Medicine, NY
| | - George A Porter
- Division of Pediatric Cardiology, Department of Pediatrics, University of Rochester School of Medicine, NY (G.A.P.)
| | - Mindong Ren
- Departments of Anesthesiology and Cell Biology (M.R.), NYU Grossman School of Medicine, NY
| | - Colin K L Phoon
- Division of Pediatric Cardiology, Department of Pediatrics (P.R., L.N., S.P., C.K.L.P.), NYU Grossman School of Medicine, NY
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Piombo S, Cooper D, Haddad F, Hughes C, Radom‐Aizik S. A novel in vitro model of the microvasculature to study monocyte activation. FASEB J 2019. [DOI: 10.1096/fasebj.2019.33.1_supplement.496.65] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Dan Cooper
- University of California, IrvineIrvineCA
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Law P, Haddad F, Zaldivar FP, Stehli A, Piombo S, Radom-Aizik S. Leukocyte and Lactate Responses to Different Modes of Exercise at the Same Target Heart Rate. Med Sci Sports Exerc 2018. [DOI: 10.1249/01.mss.0000535157.58121.14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Wagh V, Pomorski A, Wilschut KJ, Piombo S, Bernstein HS. MicroRNA-363 negatively regulates the left ventricular determining transcription factor HAND1 in human embryonic stem cell-derived cardiomyocytes. Stem Cell Res Ther 2014; 5:75. [PMID: 24906886 PMCID: PMC4097848 DOI: 10.1186/scrt464] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Accepted: 05/15/2014] [Indexed: 12/19/2022] Open
Abstract
INTRODUCTION Posttranscriptional control of mRNA by microRNA (miRNA) has been implicated in the regulation of diverse biologic processes from directed differentiation of stem cells through organism development. We describe a unique pathway by which miRNA regulates the specialized differentiation of cardiomyocyte (CM) subtypes. METHODS We differentiated human embryonic stem cells (hESCs) to cardiac progenitor cells and functional CMs, and characterized the regulated expression of specific miRNAs that target transcriptional regulators of left/right ventricular-subtype specification. RESULTS From >900 known human miRNAs in hESC-derived cardiac progenitor cells and functional CMs, a subset of differentially expressed cardiac miRNAs was identified, and in silico analysis predicted highly conserved binding sites in the 3'-untranslated regions (3'UTRs) of Hand-and-neural-crest-derivative-expressed (HAND) genes 1 and 2 that are involved in left and right ventricular development. We studied the temporal and spatial expression patterns of four miRNAs in differentiating hESCs, and found that expression of miRNA (miR)-363, miR-367, miR-181a, and miR-181c was specific for stage and site. Further analysis showed that miR-363 overexpression resulted in downregulation of HAND1 mRNA and protein levels. A dual luciferase reporter assay demonstrated functional interaction of miR-363 with the full-length 3'UTR of HAND1. Expression of anti-miR-363 in-vitro resulted in enrichment for HAND1-expressing CM subtype populations. We also showed that BMP4 treatment induced the expression of HAND2 with less effect on HAND1, whereas miR-363 overexpression selectively inhibited HAND1. CONCLUSIONS These data show that miR-363 negatively regulates the expression of HAND1 and suggest that suppression of miR-363 could provide a novel strategy for generating functional left-ventricular CMs.
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Abstract
Distributions of rupture sites of fission yeast cells ruptured by glass beads have been related to a new morphometric analysis. As shown previously (Johnson et al., Cell Biophysics, 1995), ruptures were not randomly distributed nor was their distribution dictated by geometry, rather, ruptures at the extensile end were related to cell length just as the rate of extension is related to cell length. The extension patterns of early log, mid-log, late log, and stationary phase cells from suspension cultures were found to approximate the linear growth patterns of Kubitschek and Clay (1986). The median length of cells was found to decline through the log phase in an unbalanced manner.
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Affiliation(s)
- S Piombo
- Department of Biology, Carleton University, Ottawa, Ontario, Canada
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