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Amoakon JP, Mylavarapu G, Amin RS, Naren AP. Pulmonary Vascular Dysfunctions in Cystic Fibrosis. Physiology (Bethesda) 2024; 39:0. [PMID: 38501963 DOI: 10.1152/physiol.00024.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 01/26/2024] [Accepted: 03/14/2024] [Indexed: 03/20/2024] Open
Abstract
Cystic fibrosis (CF) is an inherited disorder caused by a deleterious mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Given that the CFTR protein is a chloride channel expressed on a variety of cells throughout the human body, mutations in this gene impact several organs, particularly the lungs. For this very reason, research regarding CF disease and CFTR function has historically focused on the lung airway epithelium. Nevertheless, it was discovered more than two decades ago that CFTR is also expressed and functional on endothelial cells. Despite the great strides that have been made in understanding the role of CFTR in the airway epithelium, the role of CFTR in the endothelium remains unclear. Considering that the airway epithelium and endothelium work in tandem to allow gas exchange, it becomes very crucial to understand how a defective CFTR protein can impact the pulmonary vasculature and overall lung function. Fortunately, more recent research has been dedicated to elucidating the role of CFTR in the endothelium. As a result, several vascular dysfunctions associated with CF disease have come to light. Here, we summarize the current knowledge on pulmonary vascular dysfunctions in CF and discuss applicable therapies.
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Affiliation(s)
- Jean-Pierre Amoakon
- Department of Systems Biology and Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States
- Division of Pulmonary Medicine and Critical Care, Cedars-Sinai Medical Center, Los Angeles, California, United States
| | - Goutham Mylavarapu
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, United States
| | - Raouf S Amin
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, United States
| | - Anjaparavanda P Naren
- Department of Systems Biology and Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States
- Division of Pulmonary Medicine and Critical Care, Cedars-Sinai Medical Center, Los Angeles, California, United States
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, United States
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2
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Kachabi A, Colebank MJ, Chesler NC. Subject-specific one-dimensional fluid dynamics model of chronic thromboembolic pulmonary hypertension. Biomech Model Mechanobiol 2024; 23:469-483. [PMID: 38017302 PMCID: PMC10963496 DOI: 10.1007/s10237-023-01786-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 10/21/2023] [Indexed: 11/30/2023]
Abstract
Chronic thromboembolic pulmonary hypertension (CTEPH) develops due to the accumulation of blood clots in the lung vasculature that obstructs flow and increases pressure. The mechanobiological factors that drive progression of CTEPH are not understood, in part because mechanical and hemodynamic changes in the small pulmonary arteries due to CTEPH are not easily measurable. Using previously published hemodynamic measurements and imaging from a large animal model of CTEPH, we applied a subject-specific one-dimensional (1D) computational fluid dynamic (CFD) approach to investigate the impact of CTEPH on pulmonary artery stiffening, time-averaged wall shear stress (TAWSS), and oscillatory shear index (OSI) in extralobar (main, right, and left) pulmonary arteries and intralobar (distal to the extralobar) arteries. Our results demonstrate that CTEPH increases pulmonary artery wall stiffness and decreases TAWSS in extralobar and intralobar arteries. Moreover, CTEPH increases the percentage of the intralobar arterial network with both low TAWSS and high OSI, quantified by the novel parameter φ , which is related to thrombogenicity. Our analysis reveals a strong positive correlation between increases in mean pulmonary artery pressure (mPAP) and φ from baseline to CTEPH in individual subjects, which supports the suggestion that increased φ drives disease severity. This subject-specific experimental-computational framework shows potential as a predictor of the impact of CTEPH on pulmonary arterial hemodynamics and pulmonary vascular mechanics. By leveraging advanced modeling techniques and calibrated model parameters, we predict spatial distributions of flow and pressure, from which we can compute potential physiomarkers of disease progression. Ultimately, this approach can lead to more spatially targeted interventions that address the needs of individual CTEPH patients.
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Affiliation(s)
- Amirreza Kachabi
- Edwards Lifesciences Foundation Cardiovascular Innovation and Research Center, Department of Biomedical Engineering, University of California, Irvine, Irvine, CA, USA
| | - Mitchel J Colebank
- Edwards Lifesciences Foundation Cardiovascular Innovation and Research Center, Department of Biomedical Engineering, University of California, Irvine, Irvine, CA, USA
| | - Naomi C Chesler
- Edwards Lifesciences Foundation Cardiovascular Innovation and Research Center, Department of Biomedical Engineering, University of California, Irvine, Irvine, CA, USA.
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Kachabi A, Colebank MJ, Chesler N. Subject-specific one-dimensional fluid dynamics model of chronic thromboembolic pulmonary hypertension. RESEARCH SQUARE 2023:rs.3.rs-3214385. [PMID: 37577616 PMCID: PMC10418554 DOI: 10.21203/rs.3.rs-3214385/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
Chronic thromboembolic pulmonary hypertension (CTEPH) develops due to the accumulation of blood clots in the lung vasculature that obstruct flow and increase pressure. The mechanobiological factors that drive progression of CTEPH are not understood, in part because mechanical and hemodynamic changes in the pulmonary vasculature due to CTEPH are not easily measurable. Using previously published hemodynamic measurements and imaging from a large animal model of CTEPH, we developed a subject-specific one-dimensional (1D) computational fluid dynamic (CFD) models to investigate the impact of CTEPH on pulmonary artery stiffening, time averaged wall shear stress (TAWSS), and oscillatory shear index (OSI). Our results demonstrate that CTEPH increases pulmonary artery wall stiffness and decreases TAWSS in extralobar (main, right and left pulmonary arteries) and intralobar vessels. Moreover, CTEPH increases the percentage of the intralobar arterial network with both low TAWSS and high OSI. This subject-specific experimental-computational framework shows potential as a predictor of the impact of CTEPH on pulmonary arterial hemodynamics and pulmonary vascular mechanics. By leveraging advanced modeling techniques and calibrated model parameters, we predict spatial distributions of flow and pressure, from which we can compute potential physiomarkers of disease progression, including the combination of low mean wall shear stress with high oscillation. Ultimately, this approach can lead to more spatially targeted interventions that address the needs of individual CTEPH patients.
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Pillalamarri NR, Piskin S, Patnaik SS, Murali S, Finol EA. Patient-Specific Computational Analysis of Hemodynamics in Adult Pulmonary Hypertension. Ann Biomed Eng 2021; 49:3465-3480. [PMID: 34799807 DOI: 10.1007/s10439-021-02884-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 10/29/2021] [Indexed: 11/25/2022]
Abstract
Pulmonary hypertension (PH) is a progressive disease characterized by elevated pressure and vascular resistance in the pulmonary arteries. Nearly 250,000 hospitalizations occur annually in the US with PH as the primary or secondary condition. A definitive diagnosis of PH requires right heart catheterization (RHC) in addition to a chest computed tomography, a walking test, and others. While RHC is the gold standard for diagnosing PH, it is invasive and posseses inherent risks and contraindications. In this work, we characterized the patient-specific pulmonary hemodynamics in silico for diverse PH WHO groups. We grouped patients on the basis of mean pulmonary arterial pressure (mPAP) into three disease severity groups: at-risk ([Formula: see text], denoted with A), mild ([Formula: see text], denoted with M), and severe ([Formula: see text], denoted with S). The pulsatile flow hemodynamics was simulated by evaluating the three-dimensional Navier-Stokes system of equations using a flow solver developed by customizing OpenFOAM libraries (v5.0, The OpenFOAM Foundation). Quasi patient-specific boundary conditions were implemented using a Womersley inlet velocity profile and transient resistance outflow conditions. Hemodynamic indices such as spatially averaged wall shear stress ([Formula: see text]), wall shear stress gradient ([Formula: see text]), time-averaged wall shear stress ([Formula: see text]), oscillatory shear index ([Formula: see text]), and relative residence time ([Formula: see text]), were evaluated along with the clinical metrics pulmonary vascular resistance ([Formula: see text]), stroke volume ([Formula: see text]) and compliance ([Formula: see text]), to assess possible spatiotemporal correlations. We observed statistically significant decreases in [Formula: see text], [Formula: see text], and [Formula: see text], and increases in [Formula: see text] and [Formula: see text] with disease severity. [Formula: see text] was moderately correlated with [Formula: see text] and [Formula: see text] at the mid-notch stage of the cardiac cycle when these indices were computed using the global pulmonary arterial geometry. These results are promising in the context of a long-term goal of identifying computational biomarkers that can serve as surrogates for invasive diagnostic protocols of PH.
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Affiliation(s)
- Narasimha R Pillalamarri
- Department of Mechanical Engineering, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, 78249, USA
| | - Senol Piskin
- Department of Mechanical Engineering, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, 78249, USA
- Department of Mechanical Engineering, Istinye University, Istanbul, Turkey
| | - Sourav S Patnaik
- Department of Mechanical Engineering, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, 78249, USA
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX, USA
| | - Srinivas Murali
- Division of Cardiovascular Medicine, Allegheny Health Network, Pittsburgh, PA, USA
| | - Ender A Finol
- Department of Mechanical Engineering, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, 78249, USA.
- UTSA/UTHSA Joint Graduate Program in Biomedical Engineering, University of Texas at San Antonio, San Antonio, TX, USA.
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Gopalan D, Gibbs JSR. From Early Morphometrics to Machine Learning-What Future for Cardiovascular Imaging of the Pulmonary Circulation? Diagnostics (Basel) 2020; 10:diagnostics10121004. [PMID: 33255668 PMCID: PMC7760106 DOI: 10.3390/diagnostics10121004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Revised: 11/19/2020] [Accepted: 11/24/2020] [Indexed: 02/07/2023] Open
Abstract
Imaging plays a cardinal role in the diagnosis and management of diseases of the pulmonary circulation. Behind the picture itself, every digital image contains a wealth of quantitative data, which are hardly analysed in current routine clinical practice and this is now being transformed by radiomics. Mathematical analyses of these data using novel techniques, such as vascular morphometry (including vascular tortuosity and vascular volumes), blood flow imaging (including quantitative lung perfusion and computational flow dynamics), and artificial intelligence, are opening a window on the complex pathophysiology and structure-function relationships of pulmonary vascular diseases. They have the potential to make dramatic alterations to how clinicians investigate the pulmonary circulation, with the consequences of more rapid diagnosis and a reduction in the need for invasive procedures in the future. Applied to multimodality imaging, they can provide new information to improve disease characterization and increase diagnostic accuracy. These new technologies may be used as sophisticated biomarkers for risk prediction modelling of prognosis and for optimising the long-term management of pulmonary circulatory diseases. These innovative techniques will require evaluation in clinical trials and may in themselves serve as successful surrogate end points in trials in the years to come.
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Affiliation(s)
- Deepa Gopalan
- Imperial College Healthcare NHS Trust, London W12 0HS, UK
- Imperial College London, London SW7 2AZ, UK;
- Cambridge University Hospital, Cambridge CB2 0QQ, UK
- Correspondence: ; Tel.: +44-77-3000-7780
| | - J. Simon R. Gibbs
- Imperial College London, London SW7 2AZ, UK;
- National Heart & Lung Institute, Imperial College London, London SW3 6LY, UK
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Dieffenbach PB, Maracle M, Tschumperlin DJ, Fredenburgh LE. Mechanobiological Feedback in Pulmonary Vascular Disease. Front Physiol 2018; 9:951. [PMID: 30090065 PMCID: PMC6068271 DOI: 10.3389/fphys.2018.00951] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 06/28/2018] [Indexed: 01/06/2023] Open
Abstract
Vascular stiffening in the pulmonary arterial bed is increasingly recognized as an early disease marker and contributor to right ventricular workload in pulmonary hypertension. Changes in pulmonary artery stiffness throughout the pulmonary vascular tree lead to physiologic alterations in pressure and flow characteristics that may contribute to disease progression. These findings have led to a greater focus on the potential contributions of extracellular matrix remodeling and mechanical signaling to pulmonary hypertension pathogenesis. Several recent studies have demonstrated that the cellular response to vascular stiffness includes upregulation of signaling pathways that precipitate further vascular remodeling, a process known as mechanobiological feedback. The extracellular matrix modifiers, mechanosensors, and mechanotransducers responsible for this process have become increasingly well-recognized. In this review, we discuss the impact of vascular stiffening on pulmonary hypertension morbidity and mortality, evidence in favor of mechanobiological feedback in pulmonary hypertension pathogenesis, and the major contributors to mechanical signaling in the pulmonary vasculature.
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Affiliation(s)
- Paul B Dieffenbach
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, MA, United States
| | - Marcy Maracle
- Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Daniel J Tschumperlin
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Rochester, MN, United States
| | - Laura E Fredenburgh
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, MA, United States
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Frank BS, Ivy DD. Diagnosis, Evaluation and Treatment of Pulmonary Arterial Hypertension in Children. CHILDREN (BASEL, SWITZERLAND) 2018; 5:E44. [PMID: 29570688 PMCID: PMC5920390 DOI: 10.3390/children5040044] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/01/2018] [Revised: 02/28/2018] [Accepted: 03/16/2018] [Indexed: 12/23/2022]
Abstract
Pulmonary Hypertension (PH), the syndrome of elevated pressure in the pulmonary arteries, is associated with significant morbidity and mortality for affected children. PH is associated with a wide variety of potential underlying causes, including cardiac, pulmonary, hematologic and rheumatologic abnormalities. Regardless of the cause, for many patients the natural history of PH involves progressive elevation in pulmonary arterial resistance and pressure, right ventricular dysfunction, and eventually heart failure. In recent years, a number of pulmonary arterial hypertension (PAH)-targeted therapies have become available to reduce pulmonary artery pressure and improve outcome. A growing body of evidence in both the adult and pediatric literature demonstrates enhanced quality of life, functional status, and survival among treated patients. This review provides a description of select etiologies of PH seen in pediatrics and an update on the most recent data pertaining to evaluation and management of children with PH/PAH. The available evidence for specific classes of PAH-targeted therapies in pediatrics is additionally discussed.
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Affiliation(s)
- Benjamin S Frank
- Section of Cardiology, Department of Pediatrics, University of Colorado School of Medicine and Children's Hospital Colorado, Aurora, CO 80045, USA.
| | - D Dunbar Ivy
- Section of Cardiology, Department of Pediatrics, University of Colorado School of Medicine and Children's Hospital Colorado, Aurora, CO 80045, USA.
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8
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Image-based computational assessment of vascular wall mechanics and hemodynamics in pulmonary arterial hypertension patients. J Biomech 2017; 68:84-92. [PMID: 29310945 DOI: 10.1016/j.jbiomech.2017.12.022] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 11/30/2017] [Accepted: 12/17/2017] [Indexed: 11/20/2022]
Abstract
Pulmonary arterial hypertension (PAH) is a disease characterized by an elevated pulmonary arterial (PA) pressure. While several computational hemodynamic models of the pulmonary vasculature have been developed to understand PAH, they are lacking in some aspects, such as the vessel wall deformation and its lack of calibration against measurements in humans. Here, we describe a computational modeling framework that addresses these limitations. Specifically, computational models describing the coupling of hemodynamics and vessel wall mechanics in the pulmonary vasculature of a PAH patient and a normal subject were developed. Model parameters, consisting of linearized stiffness E of the large vessels and Windkessel parameters for each outflow branch, were calibrated against in vivo measurements of pressure, flow and vessel wall deformation obtained, respectively, from right-heart catheterization, phase-contrast and cine magnetic resonance images. Calibrated stiffness E of the proximal PA was 2.0 and 0.5 MPa for the PAH and normal models, respectively. Calibrated total compliance CT and resistance RT of the distal vessels were, respectively, 0.32 ml/mmHg and 11.3 mmHg∗min/l for the PAH model, and 2.93 ml/mmHg and 2.6 mmHg∗min/l for the normal model. These results were consistent with previous findings that the pulmonary vasculature is stiffer with more constricted distal vessels in PAH patients. Individual effects on PA pressure due to remodeling of the distal and proximal compartments of the pulmonary vasculature were also investigated in a sensitivity analysis. The analysis suggests that the remodeling of distal vasculature contributes more to the increase in PA pressure than the remodeling of proximal vasculature.
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Sheak JR, Weise-Cross L, deKay RJ, Walker BR, Jernigan NL, Resta TC. Enhanced NO-dependent pulmonary vasodilation limits increased vasoconstrictor sensitivity in neonatal chronic hypoxia. Am J Physiol Heart Circ Physiol 2017; 313:H828-H838. [PMID: 28733445 DOI: 10.1152/ajpheart.00123.2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 07/17/2017] [Accepted: 07/17/2017] [Indexed: 02/03/2023]
Abstract
Augmented vasoconstrictor reactivity is thought to play an important role in the development of chronic hypoxia (CH)-induced neonatal pulmonary hypertension. However, whether this response to CH results from pulmonary endothelial dysfunction and reduced nitric oxide (NO)-mediated vasodilation is not well understood. We hypothesized that neonatal CH enhances basal tone and pulmonary vasoconstrictor sensitivity by limiting NO-dependent pulmonary vasodilation. To test this hypothesis, we assessed the effects of the NO synthase (NOS) inhibitor Nω-nitro-l-arginine (l-NNA) on baseline pulmonary vascular resistance (PVR) and vasoconstrictor sensitivity to the thromboxane mimetic U-46619 in saline-perfused lungs (in situ) from 2-wk-old control and CH (12-day exposure, 0.5 atm) Sprague-Dawley rats. Basal tone was defined as that reversed by exogenous NO (spermine NONOate). CH neonates displayed elevated right ventricular systolic pressure (in vivo) and right ventricular hypertrophy, indicative of pulmonary hypertension. Perfused lungs from CH rats demonstrated greater baseline PVR, basal tone, and U-46619-mediated vasoconstriction compared with control rats in the absence of l-NNA. l-NNA markedly increased baseline PVR and reactivity to U-46619 in lungs from CH neonates, further augmenting vasoconstrictor sensitivity compared with control lungs. Exposure to CH also enhanced NO-dependent vasodilation to arginine vasopressin, pulmonary expression of NOS III [endothelial NOS (eNOS)], and eNOS phosphorylation at activation residue Ser1177 However, CH did not alter lung nitrotyrosine levels, a posttranslational modification reflecting [Formula: see text] scavenging of NO. We conclude that, in contrast to our hypothesis, enhanced basal tone and agonist-induced vasoconstriction after neonatal CH is limited by increased NO-dependent pulmonary vasodilation resulting from greater eNOS expression and phosphorylation at activation residue Ser1177NEW & NOTEWORTHY This research is the first to demonstrate enhanced nitric oxide-dependent vasodilation that limits increased vasoconstrictor reactivity in neonatal pulmonary hypertension. These results suggest that augmented vasoconstriction in this setting reflects changes in smooth muscle reactivity rather than a reduction in nitric oxide-dependent pulmonary vasodilation.
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Affiliation(s)
- Joshua R Sheak
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
| | - Laura Weise-Cross
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
| | - Ray J deKay
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
| | - Benjimen R Walker
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
| | - Nikki L Jernigan
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
| | - Thomas C Resta
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
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Dodson RB, Miller TA, Powers K, Yang Y, Yu B, Albertine KH, Zinkhan EK. Intrauterine growth restriction influences vascular remodeling and stiffening in the weanling rat more than sex or diet. Am J Physiol Heart Circ Physiol 2017; 312:H250-H264. [DOI: 10.1152/ajpheart.00610.2016] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 11/22/2016] [Accepted: 11/22/2016] [Indexed: 12/19/2022]
Abstract
Intrauterine growth restriction (IUGR) increases the incidence of adult cardiovascular disease (CVD). The sex-specific developmental mechanisms for IUGR-induced and Western high-fat diet (HFD) modification of CVD remain poorly understood. We hypothesized a maternal HFD in the Sprague-Dawley rat would augment IUGR-induced CVD in the offspring through decreased cardiac function and increased extracellular matrix (ECM) remodeling and stiffness in a sex-specific manner. HFD or regular diet (Reg) was given from 5 wk before mating through postnatal day (PND) 21. IUGR was induced by uterine artery ligation at embryonic day 19.5 (term = 21.5 days). At PND 21, echocardiographic assessments were made and carotid arteries tested for vascular compliance using pressure myography. Arterial samples were quantified for ECM constituents or fixed for histologic evaluation. The insult of IUGR (IUGR + Reg and IUGR + HFD) led to increased mechanical stiffness in both sexes ( P < 0.05). The combination of IUGR + HFD increased diastolic blood pressure 47% in males (M) and 35% in females (F) compared with the Con + Reg ( P < 0.05). ECM remodeling in IUGR + HFD caused fewer (M = −29%, F = −24%) but thicker elastin bands (M = 18%, F = 18%) and increased total collagen (M = 49%, F = 34%) compared with Con + Reg arteries. Remodeling in IUGR + HFD males increased medial collagen and soluble collagen ( P < 0.05). Remodeling in IUGR + HFD females increased adventitial collagen and wall thickness ( P < 0.05) and decreased matrix metalloproteinase 2 (MMP-2), advanced glycosylation end products (AGE), and receptor AGE (RAGE; P < 0.05). In summary, both IUGR + Reg and IUGR + HFD remodel ECM in PND 21 rats. While IUGR + HFD increases blood pressure, IUGR but not HFD increases vascular stiffness suggesting a specific mechanism of vascular remodeling that can be targeted to limit future disease. NEW & NOTEWORTHY We report intrauterine growth restriction (IUGR) increases vascular stiffening in both male and female rats through increased collagen content and altered elastin structure more than a high-fat diet (HFD) alone. Our study shows the importance of stiffness supporting the hypothesis that there are physiologic differences and potential windows for early intervention targeting vascular remodeling mechanisms.
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Affiliation(s)
- R. Blair Dodson
- Department of Surgery, University of Colorado at Denver Anschutz Medical Campus, Aurora, Colorado
- Department of Bioengineering, University of Colorado at Denver Anschutz Medical Campus, Aurora, Colorado
- The Pediatric Heart Lung Center, University of Colorado at Denver Anschutz Medical Campus, Aurora, Colorado
- The Laboratory for Fetal and Regenerative Biology, University of Colorado at Denver Anschutz Medical Campus, Aurora, Colorado
| | - Thomas A. Miller
- Division of Pediatric Cardiology, Department of Pediatrics, University of Utah, Salt Lake City, Utah; and
| | - Kyle Powers
- Department of Surgery, University of Colorado at Denver Anschutz Medical Campus, Aurora, Colorado
- The Pediatric Heart Lung Center, University of Colorado at Denver Anschutz Medical Campus, Aurora, Colorado
- The Laboratory for Fetal and Regenerative Biology, University of Colorado at Denver Anschutz Medical Campus, Aurora, Colorado
| | - Yueqin Yang
- Division of Pediatric Cardiology, Department of Pediatrics, University of Utah, Salt Lake City, Utah; and
| | - Baifeng Yu
- Division of Neonatology, Department of Pediatrics, University of Utah, Salt Lake City, Utah
| | - Kurt H. Albertine
- Division of Neonatology, Department of Pediatrics, University of Utah, Salt Lake City, Utah
| | - Erin K. Zinkhan
- Division of Neonatology, Department of Pediatrics, University of Utah, Salt Lake City, Utah
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Abstract
The prevalence of PH is increasing in the pediatric population, because of improved recognition and increased survival of patients, and remains a significant cause of morbidity and mortality. Recent studies have improved the understanding of pediatric PH, but management remains challenging because of a lack of evidence-based clinical trials. The growing contribution of developmental lung disease requires dedicated research to explore the use of existing therapies as well as the creation of novel therapies. Adequate study of pediatric PH will require multicenter collaboration due to the small numbers of patients, multifactorial disease causes, and practice variability.
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Affiliation(s)
- Dunbar Ivy
- Section of Pediatric Cardiology, Children's Hospital Colorado, University of Colorado School of Medicine, 13123 East 16th Avenue, B100, Aurora, CO 80045, USA.
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12
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Pulmonary Arterial Stiffness: Toward a New Paradigm in Pulmonary Arterial Hypertension Pathophysiology and Assessment. Curr Hypertens Rep 2016; 18:4. [PMID: 26733189 DOI: 10.1007/s11906-015-0609-2] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Stiffening of the pulmonary arterial bed with the subsequent increased load on the right ventricle is a paramount feature of pulmonary hypertension (PH). The pathophysiology of vascular stiffening is a complex and self-reinforcing function of extracellular matrix remodeling, driven by recruitment of circulating inflammatory cells and their interactions with resident vascular cells, and mechanotransduction of altered hemodynamic forces throughout the ventricular-vascular axis. New approaches to understanding the cell and molecular determinants of the pathophysiology combine novel biopolymer substrates, controlled flow conditions, and defined cell types to recapitulate the biomechanical environment in vitro. Simultaneously, advances are occurring to assess novel parameters of stiffness in vivo. In this comprehensive state-of-art review, we describe clinical hemodynamic markers, together with the newest translational echocardiographic and cardiac magnetic resonance imaging methods, to assess vascular stiffness and ventricular-vascular coupling. Finally, fluid-tissue interactions appear to offer a novel route of investigating the mechanotransduction processes and disease progression.
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Mandell E, Powers KN, Harral JW, Seedorf GJ, Hunter KS, Abman SH, Dodson RB. Intrauterine endotoxin-induced impairs pulmonary vascular function and right ventricular performance in infant rats and improvement with early vitamin D therapy. Am J Physiol Lung Cell Mol Physiol 2015; 309:L1438-46. [PMID: 26475735 DOI: 10.1152/ajplung.00302.2015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 10/09/2015] [Indexed: 01/04/2023] Open
Abstract
High pulmonary vascular resistance (PVR), proximal pulmonary artery (PA) impedance, and right ventricular (RV) afterload due to remodeling contribute to the pathogenesis and severity of pulmonary hypertension (PH). Intra-amniotic exposure to endotoxin (ETX) causes sustained PH and high mortality in rat pups at birth, which are associated with impaired vascular growth and RV hypertrophy in survivors. Treatment of ETX-exposed pups with antenatal vitamin D (vit D) improves survival and lung growth, but the effects of ETX exposure on RV-PA coupling in the neonatal lung are unknown. We hypothesized that intrauterine ETX impairs RV-PA coupling through sustained abnormalities of PA stiffening and RV performance that are attenuated with vit D therapy. Fetal rats were exposed to intra-amniotic injections of ETX, ETX+vit D, or saline at 20 days gestation (term = 22 days). At postnatal day 14, pups had pressure-volume measurements of the RV and isolated proximal PA, respectively. Lung homogenates were assayed for extracellular matrix (ECM) composition by Western blot. We found that ETX lungs contain decreased α-elastin, lysyl oxidase, collagen I, and collagen III proteins (P < 0.05) compared control and ETX+vit D lungs. ETX-exposed animals have increased RV mechanical stroke work (P < 0.05 vs. control and ETX+vit D) and elastic potential energy (P < 0.05 vs. control and ETX+vit D). Mechanical stiffness and ECM remodeling are increased in the PA (P < 0.05 vs. control and ETX+vit D). We conclude that intrauterine exposure of fetal rats to ETX during late gestation causes persistent impairment of RV-PA coupling throughout infancy that can be prevented with early vit D treatment.
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Affiliation(s)
- Erica Mandell
- Department of Pediatrics, University of Colorado at Denver Anschutz Medical Campus, Aurora, Colorado; The Pediatric Heart Lung Center, University of Colorado at Denver Anschutz Medical Campus, Aurora, Colorado
| | - Kyle N Powers
- Department of Surgery, University of Colorado at Denver Anschutz Medical Campus, Aurora, Colorado; The Pediatric Heart Lung Center, University of Colorado at Denver Anschutz Medical Campus, Aurora, Colorado; The Laboratory for Fetal and Regenerative Biology; and
| | - Julie W Harral
- Division of Cardiovascular Pulmonary Research, University of Colorado at Denver Anschutz Medical Campus, Aurora, Colorado
| | - Gregory J Seedorf
- Department of Pediatrics, University of Colorado at Denver Anschutz Medical Campus, Aurora, Colorado; The Pediatric Heart Lung Center, University of Colorado at Denver Anschutz Medical Campus, Aurora, Colorado
| | - Kendall S Hunter
- Department of Bioengineering, University of Colorado at Denver Anschutz Medical Campus, Aurora, Colorado
| | - Steven H Abman
- Department of Pediatrics, University of Colorado at Denver Anschutz Medical Campus, Aurora, Colorado; The Pediatric Heart Lung Center, University of Colorado at Denver Anschutz Medical Campus, Aurora, Colorado
| | - R Blair Dodson
- Department of Surgery, University of Colorado at Denver Anschutz Medical Campus, Aurora, Colorado; Department of Bioengineering, University of Colorado at Denver Anschutz Medical Campus, Aurora, Colorado; The Pediatric Heart Lung Center, University of Colorado at Denver Anschutz Medical Campus, Aurora, Colorado; The Laboratory for Fetal and Regenerative Biology; and
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14
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Bellofiore A, Henningsen J, Lepak CG, Tian L, Roldan-Alzate A, Kellihan HB, Consigny DW, Francois CJ, Chesler NC. A novel in vivo approach to assess radial and axial distensibility of large and intermediate pulmonary artery branches. J Biomech Eng 2015; 137:044501. [PMID: 25587800 DOI: 10.1115/1.4029578] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Indexed: 11/08/2022]
Abstract
Pulmonary arteries (PAs) distend to accommodate increases in cardiac output. PA distensibility protects the right ventricle (RV) from excessive increases in pressure. Loss of PA distensibility plays a critical role in the fatal progression of pulmonary arterial hypertension (PAH) toward RV failure. However, it is unclear how PA distensibility is distributed across the generations of PA branches, mainly because of the lack of appropriate in vivo methods to measure distensibility of vessels other than the large, conduit PAs. In this study, we propose a novel approach to assess the distensibility of individual PA branches. The metric of PA distensibility we used is the slope of the stretch ratio-pressure relationship. To measure distensibility, we combined invasive measurements of mean PA pressure with angiographic imaging of the PA network of six healthy female dogs. Stacks of 2D images of the PAs, obtained from either contrast enhanced magnetic resonance angiography (CE-MRA) or computed tomography digital subtraction angiography (CT-DSA), were used to reconstruct 3D surface models of the PA network, from the first bifurcation down to the sixth generation of branches. For each branch of the PA, we calculated radial and longitudinal stretch between baseline and a pressurized state obtained via acute embolization of the pulmonary vasculature. Our results indicated that large and intermediate PA branches have a radial distensibility consistently close to 2%/mmHg. Our axial distensibility data, albeit affected by larger variability, suggested that the PAs distal to the first generation may not significantly elongate in vivo, presumably due to spatial constraints. Results from both angiographic techniques were comparable to data from established phase-contrast (PC) magnetic resonance imaging (MRI) and ex vivo mechanical tests, which can only be used in the first branch generation. Our novel method can be used to characterize PA distensibility in PAH patients undergoing clinical right heart catheterization (RHC) in combination with MRI.
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15
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Dodson RB, Morgan MR, Galambos C, Hunter KS, Abman SH. Chronic intrauterine pulmonary hypertension increases main pulmonary artery stiffness and adventitial remodeling in fetal sheep. Am J Physiol Lung Cell Mol Physiol 2014; 307:L822-8. [PMID: 25326575 PMCID: PMC4254964 DOI: 10.1152/ajplung.00256.2014] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Accepted: 10/14/2014] [Indexed: 11/22/2022] Open
Abstract
Persistent pulmonary hypertension of the newborn (PPHN) is a clinical syndrome that is characterized by high pulmonary vascular resistance due to changes in lung vascular growth, structure, and tone. PPHN has been primarily considered as a disease of the small pulmonary arteries (PA), but proximal vascular stiffness has been shown to be an important predictor of morbidity and mortality in other diseases associated with pulmonary hypertension (PH). The objective of this study is to characterize main PA (MPA) stiffness in experimental PPHN and to determine the relationship of altered biomechanics of the MPA with changes in extracellular matrix (ECM) content and orientation of collagen and elastin fibers. MPAs were isolated from control and PPHN fetal sheep model and were tested by planar biaxial testing to measure stiffness in circumferential and axial vessel orientations. Test specimens were fixed for histological assessments of the vascular wall ECM constituents collagen and elastin. MPAs from PPHN sheep had increased mechanical stiffness (P < 0.05) and altered ECM remodeling compared with control MPA. A constitutive mathematical model and histology demonstrated that PPHN vessels have a smaller contribution of elastin and a greater role for collagen fiber engagement compared with the control arteries. We conclude that exposure to chronic hemodynamic stress in late-gestation fetal sheep increases proximal PA stiffness and alters ECM remodeling. We speculate that proximal PA stiffness further contributes to increased right ventricular impedance in experimental PPHN, which contributes to abnormal transition of the pulmonary circulation at birth.
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Affiliation(s)
- R Blair Dodson
- Pediatric Heart Lung Center, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado; Department of Pediatrics, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado; Department of Bioengineering, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado; and
| | - Matthew R Morgan
- Department of Biomedical Engineering, Duke University, Durham, North Carolina
| | - Csaba Galambos
- Pediatric Heart Lung Center, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado; Department of Pathology, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado
| | - Kendall S Hunter
- Department of Bioengineering, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado; and
| | - Steven H Abman
- Pediatric Heart Lung Center, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado; Department of Pediatrics, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado
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16
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Tan W, Madhavan K, Hunter KS, Park D, Stenmark KR. Vascular stiffening in pulmonary hypertension: cause or consequence? (2013 Grover Conference series). Pulm Circ 2014; 4:560-80. [PMID: 25610594 PMCID: PMC4278618 DOI: 10.1086/677370] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 05/27/2014] [Indexed: 12/24/2022] Open
Abstract
Recent studies have indicated that systemic arterial stiffening is a precursor to hypertension and that hypertension, in turn, can perpetuate arterial stiffening. Pulmonary artery (PA) stiffening is also well documented to occur in pulmonary hypertension (PH), and there is evidence that pulmonary vascular stiffness (PVS) may be a better predictor of outcome than pulmonary vascular resistance (PVR). We have hypothesized that the decreased flow-damping function of elastic PAs in PH likely initiates and/or perpetuates dysfunction of pulmonary microvasculature. Recent studies have shown that large-vessel stiffening increases flow pulsatility in the distal pulmonary vasculature, leading to endothelial dysfunction within a proinflammatory, vasoconstricting, and profibrogenic environment. The intricate role of stiffening-stimulated high pulsatile flow in endothelial cell dysfunction includes stepwise molecular events underlying PA hypertrophy, inflammation, endothelial-mesenchymal transition, and fibrosis. In addition to contributing to microenvironmental alterations of the distal vasculature, disordered proximal-distal PA coupling likely also plays a role in increasing ventricular afterload, ultimately causing right ventricle (RV) dysfunction and death. Current therapeutic treatments do not provide a realistic approach to destiffening arteries and, thus, to potentially abrogating the effects of high pulsatile flow on the distal pulmonary vasculature or the increased work imposed by stiffening on the RV. Scrutinizing the effect of PA stiffening on high pulsatile flow-induced cellular and molecular changes, and vice versa, might lead to important new therapeutic options that abrogate PA remodeling and PH development. With a clear understanding that PA stiffening may contribute to the progression of PH to an irreversible state by contributing to chronic microvascular damage in lungs, future studies should be aimed first at defining the underlying mechanisms leading to PA stiffening and then at improved treatment approaches based on these findings.
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Affiliation(s)
- Wei Tan
- Department of Pediatrics, University of Colorado Denver, Aurora, Colorado, USA
- Cardiovascular Pulmonary Research Laboratories, University of Colorado Denver, Aurora, Colorado, USA
- Department of Mechanical Engineering, University of Colorado Boulder, Boulder, Colorado, USA
| | - Krishna Madhavan
- Department of Pediatrics, University of Colorado Denver, Aurora, Colorado, USA
- Department of Bioengineering, University of Colorado Denver, Aurora, Colorado, USA
| | - Kendall S. Hunter
- Department of Pediatrics, University of Colorado Denver, Aurora, Colorado, USA
- Department of Bioengineering, University of Colorado Denver, Aurora, Colorado, USA
| | - Daewon Park
- Department of Bioengineering, University of Colorado Denver, Aurora, Colorado, USA
| | - Kurt R. Stenmark
- Department of Pediatrics, University of Colorado Denver, Aurora, Colorado, USA
- Cardiovascular Pulmonary Research Laboratories, University of Colorado Denver, Aurora, Colorado, USA
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