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LeBourdais R, Grifno GN, Banerji R, Regan K, Suki B, Nia HT. Mapping the strain-stiffening behavior of the lung and lung cancer at microscale resolution using the crystal ribcage. FRONTIERS IN NETWORK PHYSIOLOGY 2024; 4:1396593. [PMID: 39050550 PMCID: PMC11266057 DOI: 10.3389/fnetp.2024.1396593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Accepted: 06/10/2024] [Indexed: 07/27/2024]
Abstract
Lung diseases such as cancer substantially alter the mechanical properties of the organ with direct impact on the development, progression, diagnosis, and treatment response of diseases. Despite significant interest in the lung's material properties, measuring the stiffness of intact lungs at sub-alveolar resolution has not been possible. Recently, we developed the crystal ribcage to image functioning lungs at optical resolution while controlling physiological parameters such as air pressure. Here, we introduce a data-driven, multiscale network model that takes images of the lung at different distending pressures, acquired via the crystal ribcage, and produces corresponding absolute stiffness maps. Following validation, we report absolute stiffness maps of the functioning lung at microscale resolution in health and disease. For representative images of a healthy lung and a lung with primary cancer, we find that while the lung exhibits significant stiffness heterogeneity at the microscale, primary tumors introduce even greater heterogeneity into the lung's microenvironment. Additionally, we observe that while the healthy alveoli exhibit strain-stiffening of ∼1.75 times, the tumor's stiffness increases by a factor of six across the range of measured transpulmonary pressures. While the tumor stiffness is 1.4 times the lung stiffness at a transpulmonary pressure of three cmH2O, the tumor's mean stiffness is nearly five times greater than that of the surrounding tissue at a transpulmonary pressure of 18 cmH2O. Finally, we report that the variance in both strain and stiffness increases with transpulmonary pressure in both the healthy and cancerous lungs. Our new method allows quantitative assessment of disease-induced stiffness changes in the alveoli with implications for mechanotransduction.
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Affiliation(s)
| | | | | | | | | | - Hadi T. Nia
- Department of Biomedical Engineering, Boston University, Boston, MA, United States
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2
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Banerji R, Grifno GN, Shi L, Smolen D, LeBourdais R, Muhvich J, Eberman C, Hiller BE, Lee J, Regan K, Zheng S, Zhang S, Jiang J, Raslan AA, Breda JC, Pihl R, Traber K, Mazzilli S, Ligresti G, Mizgerd JP, Suki B, Nia HT. Crystal ribcage: a platform for probing real-time lung function at cellular resolution. Nat Methods 2023; 20:1790-1801. [PMID: 37710017 PMCID: PMC10860663 DOI: 10.1038/s41592-023-02004-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Accepted: 08/10/2023] [Indexed: 09/16/2023]
Abstract
Understanding the dynamic pathogenesis and treatment response in pulmonary diseases requires probing the lung at cellular resolution in real time. Despite advances in intravital imaging, optical imaging of the lung during active respiration and circulation has remained challenging. Here, we introduce the crystal ribcage: a transparent ribcage that allows multiscale optical imaging of the functioning lung from whole-organ to single-cell level. It enables the modulation of lung biophysics and immunity through intravascular, intrapulmonary, intraparenchymal and optogenetic interventions, and it preserves the three-dimensional architecture, air-liquid interface, cellular diversity and respiratory-circulatory functions of the lung. Utilizing these capabilities on murine models of pulmonary pathologies we probed remodeling of respiratory-circulatory functions at the single-alveolus and capillary levels during disease progression. The crystal ribcage and its broad applications presented here will facilitate further studies of nearly any pulmonary disease as well as lead to the identification of new targets for treatment strategies.
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Affiliation(s)
- Rohin Banerji
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Gabrielle N Grifno
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Linzheng Shi
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Dylan Smolen
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Rob LeBourdais
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Johnathan Muhvich
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Cate Eberman
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Bradley E Hiller
- Pulmonary Center, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA
| | - Jisu Lee
- Pulmonary Center, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA
| | - Kathryn Regan
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Siyi Zheng
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Sue Zhang
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - John Jiang
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Ahmed A Raslan
- Pulmonary Center, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA
- Department of Zoology, Faculty of Science, Assiut University, Assiut, Egypt
| | - Julia C Breda
- Section of Computational Biomedicine, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA
| | - Riley Pihl
- Pulmonary Center, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA
| | - Katrina Traber
- Pulmonary Center, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA
| | - Sarah Mazzilli
- Section of Computational Biomedicine, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA
| | - Giovanni Ligresti
- Pulmonary Center, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA
| | - Joseph P Mizgerd
- Pulmonary Center, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA
| | - Béla Suki
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Hadi T Nia
- Department of Biomedical Engineering, Boston University, Boston, MA, USA.
- Pulmonary Center, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA.
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3
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Weidenfeld S, Chupin C, Langner DI, Zetoun T, Rozowsky S, Kuebler WM. Sodium-coupled neutral amino acid transporter SNAT2 counteracts cardiogenic pulmonary edema by driving alveolar fluid clearance. Am J Physiol Lung Cell Mol Physiol 2021; 320:L486-L497. [PMID: 33439101 DOI: 10.1152/ajplung.00461.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The constant transport of ions across the alveolar epithelial barrier regulates alveolar fluid homeostasis. Dysregulation or inhibition of Na+ transport causes fluid accumulation in the distal airspaces resulting in impaired gas exchange and respiratory failure. Previous studies have primarily focused on the critical role of amiloride-sensitive epithelial sodium channel (ENaC) in alveolar fluid clearance (AFC), yet activation of ENaC failed to attenuate pulmonary edema in clinical trials. Since 40% of AFC is amiloride-insensitive, Na+ channels/transporters other than ENaC such as Na+-coupled neutral amino acid transporters (SNATs) may provide novel therapeutic targets. Here, we identified a key role for SNAT2 (SLC38A2) in AFC and pulmonary edema resolution. In isolated perfused mouse and rat lungs, pharmacological inhibition of SNATs by HgCl2 and α-methylaminoisobutyric acid (MeAIB) impaired AFC. Quantitative RT-PCR identified SNAT2 as the highest expressed System A transporter in pulmonary epithelial cells. Pharmacological inhibition or siRNA-mediated knockdown of SNAT2 reduced transport of l-alanine across pulmonary epithelial cells. Homozygous Slc38a2-/- mice were subviable and died shortly after birth with severe cyanosis. Isolated lungs of Slc38a2+/- mice developed higher wet-to-dry weight ratios (W/D) as compared to wild type (WT) in response to hydrostatic stress. Similarly, W/D ratios were increased in Slc38a2+/- mice as compared to controls in an acid-induced lung injury model. Our results identify SNAT2 as a functional transporter for Na+ and neutral amino acids in pulmonary epithelial cells with a relevant role in AFC and the resolution of lung edema. Activation of SNAT2 may provide a new therapeutic strategy to counteract and/or reverse pulmonary edema.
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Affiliation(s)
- Sarah Weidenfeld
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, Ontario, Canada.,Institute of Physiology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Cécile Chupin
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, Ontario, Canada
| | | | - Tamador Zetoun
- Institute of Physiology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Simon Rozowsky
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, Ontario, Canada
| | - Wolfgang M Kuebler
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, Ontario, Canada.,Department of Surgery, University of Toronto, Toronto, Ontario, Canada.,Department of Physiology, University of Toronto, Toronto, Ontario, Canada.,Institute of Physiology, Charité - Universitätsmedizin Berlin, Berlin, Germany
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4
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Philip JL, Tabima DM, Wolf GD, Frump AL, Cheng TC, Schreier DA, Hacker TA, Lahm T, Chesler NC. Exogenous Estrogen Preserves Distal Pulmonary Arterial Mechanics and Prevents Pulmonary Hypertension in Rats. Am J Respir Crit Care Med 2020; 201:371-374. [PMID: 31661294 PMCID: PMC6999110 DOI: 10.1164/rccm.201906-1217le] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
- Jennifer L. Philip
- University of Wisconsin–Madison
College of EngineeringMadison, Wisconsin
- University of Wisconsin–Madison
School of Medicine and Public HealthMadison, Wisconsin
| | - Diana M. Tabima
- University of Wisconsin–Madison
College of EngineeringMadison, Wisconsin
| | - Gregory D. Wolf
- University of Wisconsin–Madison
College of EngineeringMadison, Wisconsin
| | - Andrea L. Frump
- Indiana University School of
MedicineIndianapolis, Indianaand
| | - Tik-Chee Cheng
- University of Wisconsin–Madison
College of EngineeringMadison, Wisconsin
| | - David A. Schreier
- University of Wisconsin–Madison
College of EngineeringMadison, Wisconsin
| | - Timothy A. Hacker
- University of Wisconsin–Madison
School of Medicine and Public HealthMadison, Wisconsin
| | - Tim Lahm
- Indiana University School of
MedicineIndianapolis, Indianaand
- Richard L. Roudebush VA Medical
CenterIndianapolis, Indiana
| | - Naomi C. Chesler
- University of Wisconsin–Madison
College of EngineeringMadison, Wisconsin
- University of Wisconsin–Madison
School of Medicine and Public HealthMadison, Wisconsin
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Philip JL, Murphy TM, Schreier DA, Stevens S, Tabima DM, Albrecht M, Frump AL, Hacker TA, Lahm T, Chesler NC. Pulmonary vascular mechanical consequences of ischemic heart failure and implications for right ventricular function. Am J Physiol Heart Circ Physiol 2019; 316:H1167-H1177. [PMID: 30767670 DOI: 10.1152/ajpheart.00319.2018] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Left heart failure (LHF) is the most common cause of pulmonary hypertension, which confers an increase in morbidity and mortality in this context. Pulmonary vascular resistance has prognostic value in LHF, but otherwise the mechanical consequences of LHF for the pulmonary vasculature and right ventricle (RV) remain unknown. We sought to investigate mechanical mechanisms of pulmonary vascular and RV dysfunction in a rodent model of LHF to address the knowledge gaps in understanding disease pathophysiology. LHF was created using a left anterior descending artery ligation to cause myocardial infarction (MI) in mice. Sham animals underwent thoracotomy alone. Echocardiography demonstrated increased left ventricle (LV) volumes and decreased ejection fraction at 4 wk post-MI that did not normalize by 12 wk post-MI. Elevation of LV diastolic pressure and RV systolic pressure at 12 wk post-MI demonstrated pulmonary hypertension (PH) due to LHF. There was increased pulmonary arterial elastance and pulmonary vascular resistance associated with perivascular fibrosis without other remodeling. There was also RV contractile dysfunction with a 35% decrease in RV end-systolic elastance and 66% decrease in ventricular-vascular coupling. In this model of PH due to LHF with reduced ejection fraction, pulmonary fibrosis contributes to increased RV afterload, and loss of RV contractility contributes to RV dysfunction. These are key pathologic features of human PH secondary to LHF. In the future, novel therapeutic strategies aimed at preventing pulmonary vascular mechanical changes and RV dysfunction in the context of LHF can be tested using this model. NEW & NOTEWORTHY In this study, we investigate the mechanical consequences of left heart failure with reduced ejection fraction for the pulmonary vasculature and right ventricle. Using comprehensive functional analyses of the cardiopulmonary system in vivo and ex vivo, we demonstrate that pulmonary fibrosis contributes to increased RV afterload and loss of RV contractility contributes to RV dysfunction. Thus this model recapitulates key pathologic features of human pulmonary hypertension-left heart failure and offers a robust platform for future investigations.
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Affiliation(s)
- Jennifer L Philip
- Department of Biomedical Engineering, University of Wisconsin-Madison College of Engineering , Madison, Wisconsin.,Department of Surgery, University of Wisconsin-Madison , Madison, Wisconsin
| | - Thomas M Murphy
- Department of Biomedical Engineering, University of Wisconsin-Madison College of Engineering , Madison, Wisconsin
| | - David A Schreier
- Department of Biomedical Engineering, University of Wisconsin-Madison College of Engineering , Madison, Wisconsin
| | - Sydney Stevens
- Department of Medicine, Indiana University School of Medicine , Indianapolis, Indiana
| | - Diana M Tabima
- Department of Biomedical Engineering, University of Wisconsin-Madison College of Engineering , Madison, Wisconsin
| | - Margie Albrecht
- Department of Medicine, Indiana University School of Medicine , Indianapolis, Indiana
| | - Andrea L Frump
- Department of Medicine, Indiana University School of Medicine , Indianapolis, Indiana
| | - Timothy A Hacker
- Department of Medicine, University of Wisconsin-Madison , Madison, Wisconsin
| | - Tim Lahm
- Department of Medicine, Indiana University School of Medicine , Indianapolis, Indiana.,Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana.,Richard L. Roudebush Veterans Affairs Medical Center , Indianapolis, Indiana
| | - Naomi C Chesler
- Department of Biomedical Engineering, University of Wisconsin-Madison College of Engineering , Madison, Wisconsin.,Department of Medicine, University of Wisconsin-Madison , Madison, Wisconsin
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6
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Golob MJ, Wang Z, Prostrollo AJ, Hacker TA, Chesler NC. Limiting collagen turnover via collagenase-resistance attenuates right ventricular dysfunction and fibrosis in pulmonary arterial hypertension. Physiol Rep 2016; 4:4/11/e12815. [PMID: 27252252 PMCID: PMC4908492 DOI: 10.14814/phy2.12815] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Accepted: 05/03/2016] [Indexed: 12/22/2022] Open
Abstract
Pulmonary arterial hypertension (PAH) is a severe form of pulmonary hypertension in which right ventricular (RV) afterload is increased and death typically occurs due to decompensated RV hypertrophy and failure. Collagen accumulation has been implicated in pulmonary artery remodeling, but how it affects RV performance remains unclear. Here, we sought to identify the role of collagen turnover, defined as the balance between collagen synthesis and degradation, in RV structure and function in PAH. To do so, we exposed mutant (Col1a1R/R) mice, in which collagen type I degradation is impaired such that collagen turnover is reduced, and wild‐type (Col1a1+/+) littermates to 14 days of chronic hypoxia combined with SUGEN treatment (HySu) to recapitulate characteristics of clinical PAH. RV structure and function were measured by echocardiography, RV catheterization, and histology. Despite comparable increases in RV systolic pressure (Col1a1+/+: 46 ± 2 mmHg; Col1a1R/R: 47 ± 3 mmHg), the impaired collagen degradation in Col1a1R/R mice resulted in no RV collagen accumulation, limited RV hypertrophy, and maintained right ventricular‐pulmonary vascular coupling with HySu exposure. The preservation of cardiac function in the mutant mice indicates a beneficial role of limited collagen turnover via impaired degradation in RV remodeling in response to chronic pressure overload. Our results suggest novel treatments that reduce collagen turnover may offer a new therapeutic strategy for PAH patients.
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Affiliation(s)
- Mark J Golob
- Department of Biomedical Engineering, University of Wisconsin-Madison College of Engineering, Madison, Wisconsin Materials Science Program, University of Wisconsin-Madison College of Engineering, Madison, Wisconsin
| | - Zhijie Wang
- Department of Biomedical Engineering, University of Wisconsin-Madison College of Engineering, Madison, Wisconsin
| | - Anthony J Prostrollo
- Department of Biomedical Engineering, University of Wisconsin-Madison College of Engineering, Madison, Wisconsin
| | - Timothy A Hacker
- Department of Medicine, Medical Science Center University of Wisconsin-Madison, Madison, Wisconsin
| | - Naomi C Chesler
- Department of Biomedical Engineering, University of Wisconsin-Madison College of Engineering, Madison, Wisconsin
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7
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Schreier DA, Hacker TA, Hunter K, Eickoff J, Liu A, Song G, Chesler N. Impact of increased hematocrit on right ventricular afterload in response to chronic hypoxia. J Appl Physiol (1985) 2014; 117:833-9. [PMID: 25170068 DOI: 10.1152/japplphysiol.00059.2014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Chronic hypoxia causes chronic mountain sickness through hypoxia-induced pulmonary hypertension (HPH) and increased hematocrit. Here, we investigated the impact of increased hematocrit and HPH on right ventricular (RV) afterload via pulmonary vascular impedance. Mice were exposed to chronic normobaric hypoxia (10% oxygen) for 10 (10H) or 21 days (21H). After baseline hemodynamic measurements, ∼500 μl of blood were extracted and replaced with an equal volume of hydroxyethylstarch to normalize hematocrit and all hemodynamic measurements were repeated. In addition, ∼500 μl of blood were extracted and replaced in control mice with an equal volume of 90% hematocrit blood. Chronic hypoxia increased input resistance (Z0 increased 82% in 10H and 138% in 21H vs. CTL; P < 0.05) and characteristic impedance (ZC increased 76% in 10H and 109% in 21H vs. CTL; P < 0.05). Hematocrit normalization did not decrease mean pulmonary artery pressure but did increase cardiac output such that both Z0 and ZC decreased toward control levels. Increased hematocrit in control mice did not increase pressure but did decrease cardiac output such that Z0 increased. The paradoxical decrease in ZC with an acute drop in hematocrit and no change in pressure are likely due to inertial effects secondary to the increase in cardiac output. A novel finding of this study is that an increase in hematocrit affects the pulsatile RV afterload in addition to the steady RV afterload (Z0). Furthermore, our results highlight that the conventional interpretation of ZC as a measure of proximal artery stiffness is not valid in all physiological and pathological states.
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Affiliation(s)
- David A Schreier
- Department of Biomedical Engineering University of Wisconsin, Madison, Wisconson
| | - Timothy A Hacker
- Department of Medicine Medical Science Center, Madison, Wisconsin; and
| | - Kendall Hunter
- Department of Bioengineering University of Colorado, Aurora, Colorado
| | - Jens Eickoff
- Department of Medicine Medical Science Center, Madison, Wisconsin; and
| | - Aiping Liu
- Department of Biomedical Engineering University of Wisconsin, Madison, Wisconson
| | - Gouqing Song
- Department of Medicine Medical Science Center, Madison, Wisconsin; and
| | - Naomi Chesler
- Department of Biomedical Engineering University of Wisconsin, Madison, Wisconson; Department of Medicine Medical Science Center, Madison, Wisconsin; and
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Wang Z, Chesler NC. Pulmonary vascular wall stiffness: An important contributor to the increased right ventricular afterload with pulmonary hypertension. Pulm Circ 2011; 1:212-23. [PMID: 22034607 PMCID: PMC3198648 DOI: 10.4103/2045-8932.83453] [Citation(s) in RCA: 147] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Pulmonary hypertension (PH) is associated with structural and mechanical changes in the pulmonary vascular bed that increase right ventricular (RV) afterload. These changes, characterized by narrowing and stiffening, occur in both proximal and distal pulmonary arteries (PAs). An important consequence of arterial narrowing is increased pulmonary vascular resistance (PVR). Arterial stiffening, which can occur in both the proximal and distal pulmonary arteries, is an important index of disease progression and is a significant contributor to increased RV afterload in PH. In particular, arterial narrowing and stiffening increase the RV afterload by increasing steady and oscillatory RV work, respectively. Here we review the current state of knowledge of the causes and consequences of pulmonary arterial stiffening in PH and its impact on RV function. We review direct and indirect techniques for measuring proximal and distal pulmonary arterial stiffness, measures of arterial stiffness including elastic modulus, incremental elastic modulus, stiffness coefficient β and others, the changes in cellular function and the extracellular matrix proteins that contribute to pulmonary arterial stiffening, the consequences of PA stiffening for RV function and the clinical implications of pulmonary vascular stiffening for PH progression. Future investigation of the relationship between PA stiffening and RV dysfunction may facilitate new therapies aimed at improving RV function and thus ultimately reducing mortality in PH.
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Affiliation(s)
- Zhijie Wang
- Department of Biomedical Engineering, University of Wisconsin-Madison, Wisconsin, USA
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