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Zhang EY, Bartman CM, Prakash YS, Pabelick CM, Vogel ER. Oxygen and mechanical stretch in the developing lung: risk factors for neonatal and pediatric lung disease. Front Med (Lausanne) 2023; 10:1214108. [PMID: 37404808 PMCID: PMC10315587 DOI: 10.3389/fmed.2023.1214108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 06/01/2023] [Indexed: 07/06/2023] Open
Abstract
Chronic airway diseases, such as wheezing and asthma, remain significant sources of morbidity and mortality in the pediatric population. This is especially true for preterm infants who are impacted both by immature pulmonary development as well as disproportionate exposure to perinatal insults that may increase the risk of developing airway disease. Chronic pediatric airway disease is characterized by alterations in airway structure (remodeling) and function (increased airway hyperresponsiveness), similar to adult asthma. One of the most common perinatal risk factors for development of airway disease is respiratory support in the form of supplemental oxygen, mechanical ventilation, and/or CPAP. While clinical practice currently seeks to minimize oxygen exposure to decrease the risk of bronchopulmonary dysplasia (BPD), there is mounting evidence that lower levels of oxygen may carry risk for development of chronic airway, rather than alveolar disease. In addition, stretch exposure due to mechanical ventilation or CPAP may also play a role in development of chronic airway disease. Here, we summarize the current knowledge of the impact of perinatal oxygen and mechanical respiratory support on the development of chronic pediatric lung disease, with particular focus on pediatric airway disease. We further highlight mechanisms that could be explored as potential targets for novel therapies in the pediatric population.
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Affiliation(s)
- Emily Y. Zhang
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, United States
| | - Colleen M. Bartman
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, United States
| | - Y. S. Prakash
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, United States
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, United States
| | - Christina M. Pabelick
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, United States
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, United States
| | - Elizabeth R. Vogel
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, United States
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Wang L, Chitano P, Seow CY. Mechanopharmacology of Rho-kinase antagonism in airway smooth muscle and potential new therapy for asthma. Pharmacol Res 2020; 159:104995. [PMID: 32534100 DOI: 10.1016/j.phrs.2020.104995] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 05/20/2020] [Accepted: 06/03/2020] [Indexed: 02/06/2023]
Abstract
The principle of mechanopharmacology of airway smooth muscle (ASM) is based on the premise that physical agitation, such as pressure oscillation applied to an airway, is able to induce bronchodilation by reducing contractility and softening the cytoskeleton of ASM. Although the underlying mechanism is not entirely clear, there is evidence to suggest that large-amplitude stretches are able to disrupt the actomyosin interaction in the crossbridge cycle and weaken the cytoskeleton in ASM cells. Rho-kinase is known to enhance force generation and strengthen structural integrity of the cytoskeleton during smooth muscle activation and plays a key role in the maintenance of force during prolonged muscle contractions. Synergy in relaxation has been observed when the muscle is subject to oscillatory length change while Rho-kinase is pharmacologically inhibited. In this review, inhibition of Rho-kinase coupled to therapeutic pressure oscillation applied to the airways is explored as a combination treatment for asthma.
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Affiliation(s)
- Lu Wang
- The Centre for Heart Lung Innovation, St. Paul's Hospital, University of British Columbia, Canada.
| | - Pasquale Chitano
- The Centre for Heart Lung Innovation, St. Paul's Hospital, University of British Columbia, Canada
| | - Chun Y Seow
- The Centre for Heart Lung Innovation, St. Paul's Hospital, University of British Columbia, Canada
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Wang L, Chitano P, Paré PD, Seow CY. Mechanopharmacology and Synergistic Relaxation of Airway Smooth Muscle. ACTA ACUST UNITED AC 2019; 2:0110041-110047. [PMID: 32328573 PMCID: PMC7164492 DOI: 10.1115/1.4042477] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 12/20/2018] [Indexed: 12/02/2022]
Abstract
Asthmatic airways are stiffer than normal. We have shown that the cytoskeletal passive stiffness of airway smooth muscle (ASM) can be regulated by intracellular signaling pathways, especially those associated with Rho kinase (ROCK). We have also shown that an oscillatory strain reduces the passive stiffness of ASM and its ability to generate force. Here, we investigated the combined effect of inhibiting the ASM contraction with β2 agonist and decreasing the ASM cytoskeletal stiffness with ROCK inhibitor and/or force oscillation (FO) on the relaxation of contracted ASM. We hypothesize that the ASM relaxation can be synergistically enhanced by the combination of these interventions, because drug-induced softening of the cytoskeleton enhances the FO-induced relaxation and vice versa. Sheep tracheal strips were isotonically contracted to acetylcholine (3 × 10−5 M). At the plateau of shortening, β2 agonist salbutamol (10−7 M), ROCK inhibitor H1152 (10−7 M), and FO (square wave, 1 Hz, amplitude 6% maximal active force) were applied either alone or in combination. After adjusting for nonspecific time-dependent variation, relengthening by individual interventions with low-dose salbutamol or H1152, or small amplitude FO was not significantly different from zero. However, significant relengthening was observed in all combination treatments. The relengthening was greater than the mathematical sum of relengthening caused by individual treatments thereby demonstrating synergistic relaxation. The ASM stiffness did not change with salbutamol or H1152 treatments, but was lower with FO in combination with H1152. The results suggest that the mechanopharmacological treatment can be an effective therapy for asthma.
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Affiliation(s)
- Lu Wang
- Respiratory Division, Department of Medicine; Centre for Heart Lung Innovation, St. Paul's Hospital, University of British Columbia, Vancouver, BC V6Z 1Y6, Canada e-mail:
| | - Pasquale Chitano
- Department of Pathology and Laboratory Medicine, Centre for Heart Lung Innovation, St. Paul's Hospital, University of British Columbia, Vancouver, BC V6Z 1Y6, Canada
| | - Peter D Paré
- Respiratory Division, Department of Medicine; Centre for Heart Lung Innovation, St. Paul's Hospital, University of British Columbia, Vancouver, BC V6Z 1Y6, Canada
| | - Chun Y Seow
- Department of Pathology and Laboratory Medicine, Centre for Heart Lung Innovation, St. Paul's Hospital, University of British Columbia, Vancouver, BC V6Z 1Y6, Canada
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A vacuum-actuated microtissue stretcher for long-term exposure to oscillatory strain within a 3D matrix. Biomed Microdevices 2018; 20:43. [PMID: 29808253 DOI: 10.1007/s10544-018-0286-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Abstract
Although our understanding of cellular behavior in response to extracellular biological and mechanical stimuli has greatly advanced using conventional 2D cell culture methods, these techniques lack physiological relevance. To a cell, the extracellular environment of a 2D plastic petri dish is artificially flat, extremely rigid, static and void of matrix protein. In contrast, we developed the microtissue vacuum-actuated stretcher (MVAS) to probe cellular behavior within a 3D multicellular environment composed of innate matrix protein, and in response to continuous uniaxial stretch. An array format, compatibility with live imaging and high-throughput fabrication techniques make the MVAS highly suited for biomedical research and pharmaceutical discovery. We validated our approach by characterizing the bulk microtissue strain, the microtissue strain field and single cell strain, and by assessing F-actin expression in response to chronic cyclic strain of 10%. The MVAS was shown to be capable of delivering reproducible dynamic bulk strain amplitudes up to 13%. The strain at the single cell level was found to be 10.4% less than the microtissue axial strain due to cellular rotation. Chronic cyclic strain produced a 35% increase in F-actin expression consistent with cytoskeletal reinforcement previously observed in 2D cell culture. The MVAS may further our understanding of the reciprocity shared between cells and their environment, which is critical to meaningful biomedical research and successful therapeutic approaches.
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Le Guen M, Grassin-Delyle S, Naline E, Buenestado A, Brollo M, Longchampt E, Kleinmann P, Devillier P, Faisy C. The impact of low-frequency, low-force cyclic stretching of human bronchi on airway responsiveness. Respir Res 2016; 17:151. [PMID: 27842540 PMCID: PMC5109770 DOI: 10.1186/s12931-016-0464-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 11/01/2016] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND In vivo, the airways are constantly subjected to oscillatory strain (due to tidal breathing during spontaneous respiration) and (in the event of mechanical ventilation) positive pressure. This exposure is especially problematic for the cartilage-free bronchial tree. The effects of cyclic stretching (other than high-force stretching) have not been extensively characterized. Hence, the objective of the present study was to investigate the functional and transcriptional response of human bronchi to repetitive mechanical stress caused by low-frequency, low-force cyclic stretching. METHODS After preparation and equilibration in an organ bath, human bronchial rings from 66 thoracic surgery patients were stretched in 1-min cycles of elongation and relaxation over a 60-min period. For each segment, the maximal tension corresponded to 80% of the reference contraction (the response to 3 mM acetylcholine). The impact of cyclic stretching (relative to non-stretched controls) was examined by performing functional assessments (epithelium removal and incubation with sodium channel agonists/antagonists or inhibitors of intracellular pathways), biochemical assays of the organ bath fluid (for detecting the release of pro-inflammatory cytokines), and RT-PCR assays of RNA isolated from tissue samples. RESULTS The application of low-force cyclic stretching to human bronchial rings for 60 min resulted in an immediate, significant increase in bronchial basal tone, relative to non-cyclic stretching (4.24 ± 0.16 g vs. 3.28 ± 0.12 g, respectively; p < 0.001). This cyclic stimulus also increased the affinity for acetylcholine (-log EC50: 5.67 ± 0.07 vs. 5.32 ± 0.07, respectively; p p < 0.001). Removal of airway epithelium and pretreatment with the Rho-kinase inhibitor Y27632 and inward-rectifier K+ or L-type Ca2+ channel inhibitors significantly modified the basal tone response. Exposure to L-NAME had opposing effects in all cases. Pro-inflammatory pathways were not involved in the response; cyclic stretching up-regulated the early mRNA expression of MMP9 only, and was not associated with changes in organ bath levels of pro-inflammatory mediators. CONCLUSION Low-frequency, low-force cyclic stretching of whole human bronchi induced a myogenic response rather than activation of the pro-inflammatory signaling pathways mediated by mechanotransduction.
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Affiliation(s)
- Morgan Le Guen
- Laboratory of Research in Respiratory Pharmacology - UPRES EA220, Université Versailles - Saint-Quentin, 11 rue Guillaume Lenoir, F-92150, Suresnes, France. .,Department of Anesthesiology, Hôpital Foch, Université Versailles - Saint-Quentin, Suresnes, France.
| | - Stanislas Grassin-Delyle
- Laboratory of Research in Respiratory Pharmacology - UPRES EA220, Université Versailles - Saint-Quentin, 11 rue Guillaume Lenoir, F-92150, Suresnes, France
| | - Emmanuel Naline
- Laboratory of Research in Respiratory Pharmacology - UPRES EA220, Université Versailles - Saint-Quentin, 11 rue Guillaume Lenoir, F-92150, Suresnes, France
| | - Amparo Buenestado
- Laboratory of Research in Respiratory Pharmacology - UPRES EA220, Université Versailles - Saint-Quentin, 11 rue Guillaume Lenoir, F-92150, Suresnes, France
| | - Marion Brollo
- Laboratory of Research in Respiratory Pharmacology - UPRES EA220, Université Versailles - Saint-Quentin, 11 rue Guillaume Lenoir, F-92150, Suresnes, France
| | | | - Philippe Kleinmann
- Department of Thoracic Surgery, Centre Médico-Chirurgical du Val d'Or, Saint-Cloud, France
| | - Philippe Devillier
- Laboratory of Research in Respiratory Pharmacology - UPRES EA220, Université Versailles - Saint-Quentin, 11 rue Guillaume Lenoir, F-92150, Suresnes, France
| | - Christophe Faisy
- Laboratory of Research in Respiratory Pharmacology - UPRES EA220, Université Versailles - Saint-Quentin, 11 rue Guillaume Lenoir, F-92150, Suresnes, France
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Noble PB, Pascoe CD, Lan B, Ito S, Kistemaker LEM, Tatler AL, Pera T, Brook BS, Gosens R, West AR. Airway smooth muscle in asthma: linking contraction and mechanotransduction to disease pathogenesis and remodelling. Pulm Pharmacol Ther 2014; 29:96-107. [PMID: 25062835 DOI: 10.1016/j.pupt.2014.07.005] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2014] [Revised: 07/12/2014] [Accepted: 07/15/2014] [Indexed: 02/07/2023]
Abstract
Asthma is an obstructive airway disease, with a heterogeneous and multifactorial pathogenesis. Although generally considered to be a disease principally driven by chronic inflammation, it is becoming increasingly recognised that the immune component of the pathology poorly correlates with the clinical symptoms of asthma, thus highlighting a potentially central role for non-immune cells. In this context airway smooth muscle (ASM) may be a key player, as it comprises a significant proportion of the airway wall and is the ultimate effector of acute airway narrowing. Historically, the contribution of ASM to asthma pathogenesis has been contentious, yet emerging evidence suggests that ASM contractile activation imparts chronic effects that extend well beyond the temporary effects of bronchoconstriction. In this review article we describe the effects that ASM contraction, in combination with cellular mechanotransduction and novel contraction-inflammation synergies, contribute to asthma pathogenesis. Specific emphasis will be placed on the effects that ASM contraction exerts on the mechanical properties of the airway wall, as well as novel mechanisms by which ASM contraction may contribute to more established features of asthma such as airway wall remodelling.
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Affiliation(s)
- Peter B Noble
- School of Anatomy, Physiology and Human Biology, University of Western Australia, WA, Australia
| | - Chris D Pascoe
- Center for Heart Lung Innovation, University of British Columbia, BC, Canada
| | - Bo Lan
- Center for Heart Lung Innovation, University of British Columbia, BC, Canada; Bioengineering College, Chongqing University, Chongqing, China
| | - Satoru Ito
- Department of Respiratory Medicine, Nagoya University, Aichi, Japan
| | - Loes E M Kistemaker
- Department of Molecular Pharmacology, University of Groningen, The Netherlands
| | - Amanda L Tatler
- Division of Respiratory Medicine, University of Nottingham, United Kingdom
| | - Tonio Pera
- Center for Translational Medicine, Thomas Jefferson University, Philadelphia, PA, USA
| | - Bindi S Brook
- School of Mathematical Sciences, University of Nottingham, United Kingdom
| | - Reinoud Gosens
- Department of Molecular Pharmacology, University of Groningen, The Netherlands
| | - Adrian R West
- Department of Physiology, University of Manitoba, MB, Canada; Biology of Breathing, Manitoba Institute of Child Health, MB, Canada.
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Brook BS. Emergence of airway smooth muscle mechanical behavior through dynamic reorganization of contractile units and force transmission pathways. J Appl Physiol (1985) 2014; 116:980-97. [PMID: 24481961 DOI: 10.1152/japplphysiol.01209.2013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Airway hyperresponsiveness (AHR) in asthma remains poorly understood despite significant research effort to elucidate relevant underlying mechanisms. In particular, a significant body of experimental work has focused on the effect of tidal fluctuations on airway smooth muscle (ASM) cells, tissues, lung slices, and whole airways to understand the bronchodilating effect of tidal breathing and deep inspirations. These studies have motivated conceptual models that involve dynamic reorganization of both cytoskeletal components as well as contractile machinery. In this article, a biophysical model of the whole ASM cell is presented that combines 1) crossbridge cycling between actin and myosin; 2) actin-myosin disconnectivity, under imposed length changes, to allow dynamic reconfiguration of "force transmission pathways"; and 3) dynamic parallel-to-serial transitions of contractile units within these pathways that occur through a length fluctuation. Results of this theoretical model suggest that behavior characteristic of experimentally observed force-length loops of maximally activated ASM strips can be explained by interactions among the three mechanisms. Crucially, both sustained disconnectivity and parallel-to-serial transitions are necessary to explain the nature of hysteresis and strain stiffening observed experimentally. The results provide strong evidence that dynamic rearrangement of contractile machinery is a likely mechanism underlying many of the phenomena observed at timescales associated with tidal breathing. This theoretical cell-level model captures many of the salient features of mechanical behavior observed experimentally and should provide a useful starting block for a bottom-up approach to understanding tissue-level mechanical behavior.
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Affiliation(s)
- Bindi S Brook
- School of Mathematical Sciences, University of Nottingham, Nottingham, United Kingdom
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8
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Proteomic analysis of rat proximal tubule cells following stretch-induced apoptosis in an in vitro model of kidney obstruction. J Proteomics 2013; 100:125-35. [PMID: 24316357 DOI: 10.1016/j.jprot.2013.11.025] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2013] [Revised: 09/06/2013] [Accepted: 11/22/2013] [Indexed: 01/05/2023]
Abstract
UNLABELLED Urinary tract obstruction (UTO) is a commonly noted disorder on prenatal ultrasound that has the potential to lead to permanent loss of renal function. To study the molecular processes of the disease, an in vitro model has been developed which involves mechanical stretch of proximal tubule cells grown on flexible plates which mimics the physiological conditions during UTO. This study employs a one dimensional SDS-PAGE fractionation procedure, followed by in-gel digest and LC-MS/MS analysis in a semi-quantitative experiment using spectral counting to relatively quantify changes in protein expression following the established model of UTO. Quantitative analysis shows 317 of the 1630 identified proteins express altered abundance, with 135 increased and 182 decreased in abundance as a result of stretch. Gene ontology (GO) and KEGG annotations implicate a number of physiological processes that have been previously shown in addition to some potentially novel processes in UTO. The quantitative proteomic analysis we performed here provides a more complete characterization of changes in protein abundance as a result of stretch than previous studies, and provides a number of previously undescribed proteins in proximal tubule cells that may play a role in UTO. BIOLOGICAL SIGNIFICANCE Urinary tract obstruction (UTO) is a commonly noted abnormality on prenatal ultrasound that can either resolve spontaneously or require surgical intervention to prevent permanent renal damage or loss of function. While targeted studies of UTO have shown a number of pathological responses in proximal tubule cells, there are currently no large-scale quantitative studies that aim to elucidate a global cellular response. This study uses a semi-quantitative approach and applies a well characterized model of UTO to determine a number of cellular processes affected by UTO simulation and identifies a number of proteins with altered abundance that have not been noted previously in UTO. This article is part of a Special Issue entitled: Can Proteomics Fill the Gap Between Genomics and Phenotypes?
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Chen M, Zhang W, Lu X, Hoggatt AM, Gunst SJ, Kassab GS, Tune JD, Herring BP. Regulation of 130-kDa smooth muscle myosin light chain kinase expression by an intronic CArG element. J Biol Chem 2013; 288:34647-57. [PMID: 24151072 DOI: 10.1074/jbc.m113.510362] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The mylk1 gene encodes a 220-kDa nonmuscle myosin light chain kinase (MLCK), a 130-kDa smooth muscle MLCK (smMLCK), as well as the non-catalytic product telokin. Together, these proteins play critical roles in regulating smooth muscle contractility. Changes in their expression are associated with many pathological conditions; thus, it is important to understand the mechanisms regulating expression of mylk1 gene transcripts. Previously, we reported a highly conserved CArG box, which binds serum response factor, in intron 15 of mylk1. Because this CArG element is near the promoter that drives transcription of the 130-kDa smMLCK, we examined its role in regulating expression of this transcript. Results show that deletion of the intronic CArG region from a β-galactosidase reporter gene abolished transgene expression in mice in vivo. Deletion of the CArG region from the endogenous mylk1 gene, specifically in smooth muscle cells, decreased expression of the 130-kDa smMLCK by 40% without affecting expression of the 220-kDa MLCK or telokin. This reduction in 130-kDa smMLCK expression resulted in decreased phosphorylation of myosin light chains, attenuated smooth muscle contractility, and a 24% decrease in small intestine length that was associated with a significant reduction of Ki67-positive smooth muscle cells. Overall, these data show that the CArG element in intron 15 of the mylk1 gene is necessary for maximal expression of the 130-kDa smMLCK and that the 130-kDa smMLCK isoform is specifically required to regulate smooth muscle contractility and small intestine smooth muscle cell proliferation.
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Affiliation(s)
- Meng Chen
- From the Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana 46202
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Harvey BC, Parameswaran H, Lutchen KR. Can tidal breathing with deep inspirations of intact airways create sustained bronchoprotection or bronchodilation? J Appl Physiol (1985) 2013; 115:436-45. [PMID: 23722710 DOI: 10.1152/japplphysiol.00009.2013] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Fluctuating forces imposed on the airway smooth muscle due to breathing are believed to regulate hyperresponsiveness in vivo. However, recent animal and human isolated airway studies have shown that typical breathing-sized transmural pressure (Ptm) oscillations around a fixed mean are ineffective at mitigating airway constriction. To help understand this discrepancy, we hypothesized that Ptm oscillations capable of producing the same degree of bronchodilation as observed in airway smooth muscle strip studies requires imposition of strains larger than those expected to occur in vivo. First, we applied increasingly larger amplitude Ptm oscillations to a statically constricted airway from a Ptm simulating normal functional residual capacity of 5 cmH2O. Tidal-like oscillations (5-10 cmH2O) imposed 4.9 ± 2.0% strain and resulted in 11.6 ± 4.8% recovery, while Ptm oscillations simulating a deep inspiration at every breath (5-30 cmH2O) achieved 62.9 ± 12.1% recovery. These same Ptm oscillations were then applied starting from a Ptm = 1 cmH2O, resulting in approximately double the strain for each oscillation amplitude. When extreme strains were imposed, we observed full recovery. On combining the two data sets, we found a linear relationship between strain and resultant recovery. Finally, we compared the impact of Ptm oscillations before and after constriction to Ptm oscillations applied only after constriction and found that both loading conditions had a similar effect on narrowing. We conclude that, while sufficiently large strains applied to the airway wall are capable of producing substantial bronchodilation, the Ptm oscillations necessary to achieve those strains are not expected to occur in vivo.
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Affiliation(s)
- Brian C Harvey
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts 02215, USA.
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Hernandez JM, Janssen LJ. L-type Ca2+ channels, Ca2+-induced Ca2+ release, and BKCa channels in airway stretch-induced contraction. Eur J Pharmacol 2012; 696:161-5. [DOI: 10.1016/j.ejphar.2012.09.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Revised: 09/06/2012] [Accepted: 09/17/2012] [Indexed: 02/05/2023]
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12
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West AR, Zaman N, Cole DJ, Walker MJ, Legant WR, Boudou T, Chen CS, Favreau JT, Gaudette GR, Cowley EA, Maksym GN. Development and characterization of a 3D multicell microtissue culture model of airway smooth muscle. Am J Physiol Lung Cell Mol Physiol 2012; 304:L4-16. [PMID: 23125251 DOI: 10.1152/ajplung.00168.2012] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Airway smooth muscle (ASM) cellular and molecular biology is typically studied with single-cell cultures grown on flat 2D substrates. However, cells in vivo exist as part of complex 3D structures, and it is well established in other cell types that altering substrate geometry exerts potent effects on phenotype and function. These factors may be especially relevant to asthma, a disease characterized by structural remodeling of the airway wall, and highlights a need for more physiologically relevant models of ASM function. We utilized a tissue engineering platform known as microfabricated tissue gauges to develop a 3D culture model of ASM featuring arrays of ∼0.4 mm long, ∼350 cell "microtissues" capable of simultaneous contractile force measurement and cell-level microscopy. ASM-only microtissues generated baseline tension, exhibited strong cellular organization, and developed actin stress fibers, but lost structural integrity and dissociated from the cantilevers within 3 days. Addition of 3T3-fibroblasts dramatically improved survival times without affecting tension development or morphology. ASM-3T3 microtissues contracted similarly to ex vivo ASM, exhibiting reproducible responses to a range of contractile and relaxant agents. Compared with 2D cultures, microtissues demonstrated identical responses to acetylcholine and KCl, but not histamine, forskolin, or cytochalasin D, suggesting that contractility is regulated by substrate geometry. Microtissues represent a novel model for studying ASM, incorporating a physiological 3D structure, realistic mechanical environment, coculture of multiple cells types, and comparable contractile properties to existing models. This new model allows for rapid screening of biochemical and mechanical factors to provide insight into ASM dysfunction in asthma.
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Affiliation(s)
- Adrian R West
- School of Biomedical Engineering, Dalhousie University, Halifax, Nova Scotia, Canada.
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Wright D, Sharma P, Ryu MH, Rissé PA, Ngo M, Maarsingh H, Koziol-White C, Jha A, Halayko AJ, West AR. Models to study airway smooth muscle contraction in vivo, ex vivo and in vitro: implications in understanding asthma. Pulm Pharmacol Ther 2012; 26:24-36. [PMID: 22967819 DOI: 10.1016/j.pupt.2012.08.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Revised: 08/14/2012] [Accepted: 08/17/2012] [Indexed: 11/16/2022]
Abstract
Asthma is a chronic obstructive airway disease characterised by airway hyperresponsiveness (AHR) and airway wall remodelling. The effector of airway narrowing is the contraction of airway smooth muscle (ASM), yet the question of whether an inherent or acquired dysfunction in ASM contractile function plays a significant role in the disease pathophysiology remains contentious. The difficulty in determining the role of ASM lies in limitations with the models used to assess contraction. In vivo models provide a fully integrated physiological response but ASM contraction cannot be directly measured. Ex vivo and in vitro models can provide more direct assessment of ASM contraction but the loss of factors that may modulate ASM responsiveness and AHR, including interaction between multiple cell types and disruption of the mechanical environment, precludes a complete understanding of the disease process. In this review we detail key advantages of common in vivo, ex vivo and in vitro models of ASM contraction, as well as emerging tissue engineered models of ASM and whole airways. We also highlight important findings from each model with respect to the pathophysiology of asthma.
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Affiliation(s)
- David Wright
- Medical Research Council and Asthma UK Centre in Allergic Mechanisms of Asthma, King's College London, United Kingdom
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Hernandez JM, Janssen LJ. Thromboxane Prostanoid Receptor Activation Amplifies Airway Stretch-Activated Contractions Assessed in Perfused Intact Bovine Bronchial Segments. J Pharmacol Exp Ther 2011; 339:248-56. [DOI: 10.1124/jpet.111.182246] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
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Malvè M, del Palomar AP, Chandra S, López-Villalobos JL, Finol EA, Ginel A, Doblaré M. FSI Analysis of a Human Trachea Before and After Prosthesis Implantation. J Biomech Eng 2011; 133:071003. [DOI: 10.1115/1.4004315] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
In this work we analyzed the response of a stenotic trachea after a stent implantation. An endotracheal stent is the common treatment for tracheal diseases such as stenosis, chronic cough, or dispnoea episodes. Medical treatment and surgical techniques are still challenging due to the difficulties in overcoming potential complications after prosthesis implantation. A finite element model of a diseased and stented trachea was developed starting from a patient specific computerized tomography (CT) scan. The tracheal wall was modeled as a fiber reinforced hyperelastic material in which we modeled the anisotropy due to the orientation of the collagen fibers. Deformations of the tracheal cartilage rings and of the muscular membrane, as well as the maximum principal stresses, are analyzed using a fluid solid interaction (FSI) approach. For this reason, as boundary conditions, impedance-based pressure waveforms were computed modeling the nonreconstructed vessels as a binary fractal network. The results showed that the presence of the stent prevents tracheal muscle deflections and indicated a local recirculatory flow on the stent top surface which may play a role in the process of mucous accumulation. The present work gives new insight into clinical procedures, predicting their mechanical consequences. This tool could be used in the future as preoperative planning software to help the thoracic surgeons in deciding the optimal prosthesis type as well as its size and positioning.
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Affiliation(s)
- M. Malvè
- Group of Structural Mechanics and Materials Modeling Aragón Institute of Engineering Research (I3A) Universidad de Zaragoza C/María de Luna s/n, E-50018 Zaragoza, Spain Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), C/Poeta Mariano Esquillor s/n, 50018 Zaragoza, Spain e-mail:
| | - A. Pérez del Palomar
- M2BE—Multiscale in Mechanical and Biological Engineering, Aragón Institute of Engineering Research (I3A), Universidad de Zaragoza, C/María de Luna s/n, E-50018 Zaragoza, Spain
| | - S. Chandra
- Institute for Complex Engineered Systems (ICES), Carnegie Mellon University, 1205 Hamburg Hall, 5000 Forbes Avenue, Pittsburgh, PA 15213
| | - J. L. López-Villalobos
- Hospital Virgen del Rocío, Department of Thoracic Surgery, Avenida de Manuel Siurot s/n, 41013, Seville, Spain
| | - E. A. Finol
- Institute for Complex Engineered Systems (ICES), Carnegie Mellon University, 1205 Hamburg Hall, 5000 Forbes Avenue, Pittsburgh, PA 15213
| | - A. Ginel
- Hospital Virgen del Rocío, Department of Thoracic Surgery, Avenida de Manuel Siurot s/n, 41013, Seville, Spain
| | - M. Doblaré
- Group of Structural Mechanics and Materials Modeling Aragón Institute of Engineering Research (I3A) Universidad de Zaragoza C/María de Luna s/n, 50018 Zaragoza, Spain Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), C/Poeta Mariano Esquillor s/n, E-50018 Zaragoza, Spain
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Connolly SC, Smith PG, Fairbank NJ, Lall CA, Cole DJ, Mackinnon JD, Maksym GN. Chronic oscillatory strain induces MLCK associated rapid recovery from acute stretch in airway smooth muscle cells. J Appl Physiol (1985) 2011; 111:955-63. [PMID: 21737821 DOI: 10.1152/japplphysiol.00812.2009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A deep inspiration (DI) temporarily relaxes agonist-constricted airways in normal subjects, but in asthma airways are refractory and may rapidly renarrow, possibly due to changes in the structure and function of airway smooth muscle (ASM). Chronic largely uniaxial cyclic strain of ASM cells in culture causes several structural and functional changes in ASM similar to that in asthma, including increases in contractility, MLCK content, shortening velocity, and shortening capacity. However, changes in recovery from acute stretch similar to a DI have not been measured. We have therefore measured the response and recovery to large stretches of cells modified by chronic stretching and investigated the role of MLCK. Chronic, 10% uniaxial cyclic stretch, with or without a strain gradient, was administered for up to 11 days to cultured cells grown on Silastic membranes. Single cells were then removed from the membrane and subjected to 1 Hz oscillatory stretches up to 10% of the in situ cell length. These oscillations reduced stiffness by 66% in all groups (P < 0.05). Chronically strained cells recovered stiffness three times more rapidly than unstrained cells, while the strain gradient had no effect. The stiffness recovery in unstrained cells was completely inhibited by the MLCK inhibitor ML-7, but recovery in strained cells exhibiting increased MLCK was slightly inhibited. These data suggest that chronic strain leads to enhanced recovery from acute stretch, which may be attributable to the strain-induced increases in MLCK. This may also explain in part the more rapid renarrowing of activated airways following DI in asthma.
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Affiliation(s)
- Sarah C Connolly
- School of Biomedical Engineering, Dalhousie University, Halifax, Nova Scotia, Canada
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Pérez del Palomar A, Trabelsi O, Mena A, López-Villalobos JL, Ginel A, Doblaré M. Patient-specific models of human trachea to predict mechanical consequences of endoprosthesis implantation. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2010; 368:2881-2896. [PMID: 20478912 DOI: 10.1098/rsta.2010.0092] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Nowadays, interventions associated with the implantation of tracheal prostheses in patients with airway pathologies are very common. This surgery may promote problems such as migration of the prosthesis, development of granulation tissue at the edges of the stent with overgrowth of the tracheal lumen or accumulation of secretions inside the prosthesis. Among the movements that the trachea carries out, swallowing seems to have harmful consequences for the tracheal tissues surrounding the prosthesis. In this work, a finite-element-based tool is presented to construct patient-specific tracheal models, introducing the endotracheal prosthesis and analysing the mechanical consequences of this surgery during swallowing. A complete description of a patient-specific tracheal model is given, and a fully experimental characterization of the tracheal tissues is presented. To construct patient-specific grids, a mesh adaptation algorithm has been developed and the implantation of a tracheal prosthesis is simulated. The ascending deglutition movement of the trachea is recorded using real data from each specific patient from fluoroscopic images before and after implantation. The overall behaviour of the trachea is modified when a prosthesis is introduced. The presented tool has been particularized for two different patients (patient A and patient B), allowing prediction of the consequences of this kind of surgery. In particular, patient A had a decrease of almost 30 per cent in his ability to swallow, and an increase in stresses that were three times higher after prosthesis implantation. In contrast, patient B, who had a shorter trachea and who seemed to undergo more damaging effects, did not have a significant reduction in his ability to swallow and did not present an increase in stress in the tissues. In both cases, there are clinical studies that validate our results: namely, patient A underwent a further intervention whereas the outcome of patient B's surgery was completely successful. Notwithstanding the fact that there are a lot of uncertainties relating to the implantation of endotracheal prostheses, the present work gives a new insight into these procedures, predicting their mechanical consequences. This tool could be used in the future as pre-operative planning software to help thoracic surgeons in deciding the optimal prosthesis as well as its size and positioning.
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Affiliation(s)
- A Pérez del Palomar
- Group of Structural Mechanics and Materials Modeling, Aragón Institute of Engineering Research (I3A), Universidad de Zaragoza (Spain), C/Maria de Luna 3, 50018 Zaragoza, Spain.
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Deng L, Bosse Y, Brown N, Chin LYM, Connolly SC, Fairbank NJ, King GG, Maksym GN, Paré PD, Seow CY, Stephen NL. Stress and strain in the contractile and cytoskeletal filaments of airway smooth muscle. Pulm Pharmacol Ther 2009; 22:407-16. [PMID: 19409505 DOI: 10.1016/j.pupt.2009.04.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2008] [Revised: 04/16/2009] [Accepted: 04/21/2009] [Indexed: 10/20/2022]
Abstract
Stress and strain are omnipresent in the lung due to constant lung volume fluctuation associated with respiration, and they modulate the phenotype and function of all cells residing in the airways including the airway smooth muscle (ASM) cell. There is ample evidence that the ASM cell is very sensitive to its physical environment, and can alter its structure and/or function accordingly, resulting in either desired or undesired consequences. The forces that are either conferred to the ASM cell due to external stretching or generated inside the cell must be borne and transmitted inside the cytoskeleton (CSK). Thus, maintaining appropriate levels of stress and strain within the CSK is essential for maintaining normal function. Despite the importance, the mechanisms regulating/dysregulating ASM cytoskeletal filaments in response to stress and strain remained poorly understood until only recently. For example, it is now understood that ASM length and force are dynamically regulated, and both can adapt over a wide range of length, rendering ASM one of the most malleable living tissues. The malleability reflects the CSK's dynamic mechanical properties and plasticity, both of which strongly interact with the loading on the CSK, and all together ultimately determines airway narrowing in pathology. Here we review the latest advances in our understanding of stress and strain in ASM cells, including the organization of contractile and cytoskeletal filaments, range and adaptation of functional length, structural and functional changes of the cell in response to mechanical perturbation, ASM tone as a mediator of strain-induced responses, and the novel glassy dynamic behaviors of the CSK in relation to asthma pathophysiology.
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Affiliation(s)
- Linhong Deng
- Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, and National 985 Project Institute of Biorheology and Gene Regulation, Bioengineering College, Chongqing University, Chongqing, China.
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19
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Cooper PR, McParland BE, Mitchell HW, Noble PB, Politi AZ, Ressmeyer AR, West AR. Airway mechanics and methods used to visualize smooth muscle dynamics in vitro. Pulm Pharmacol Ther 2008; 22:398-406. [PMID: 19041411 DOI: 10.1016/j.pupt.2008.09.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2008] [Accepted: 09/01/2008] [Indexed: 11/24/2022]
Abstract
Contraction of airway smooth muscle (ASM) is regulated by the physiological, structural and mechanical environment in the lung. We review two in vitro techniques, lung slices and airway segment preparations, that enable in situ ASM contraction and airway narrowing to be visualized. Lung slices and airway segment approaches bridge a gap between cell culture and isolated ASM, and whole animal studies. Imaging techniques enable key upstream events involved in airway narrowing, such as ASM cell signalling and structural and mechanical events impinging on ASM, to be investigated.
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Affiliation(s)
- P R Cooper
- Department of Medicine and the Airway Biology Initiative, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
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20
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NKCC-1 and ENaC are down-regulated in nitrofen-induced hypoplastic lungs with congenital diaphragmatic hernia. Pediatr Surg Int 2008; 24:993-1000. [PMID: 18668250 DOI: 10.1007/s00383-008-2209-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/09/2008] [Indexed: 10/21/2022]
Abstract
Congenital diaphragmatic hernia (CDH) is accompanied by pulmonary hypoplasia and pulmonary hypertension. Fetal lung growth is dependent on the secretion of lung liquid, which normally is absorbed at partus. The ion channel NKCC-1 is involved in this secretory process, but has recently also been reported to be implicated in absorption. CDH patients show a disturbed transition from secretion to absorption. alpha- and beta-ENaC are essential for lung liquid absorption. Common for all transcellular ion transport is the need for Na/K-ATPase as a primary driving force. The aim of the study was first to map the normal pulmonary expression of the above proteins during late gestation and secondly to see if the expression was affected in a CDH rat model. Pregnant Sprague-Dawley rat dams were given nitrofen on gestational day 9.5 to induce CDH. The fetuses were removed on gestational days E18 and E21. In addition, newborn rats were harvested postpartum on day P2. The fetuses were put into one of two groups: hypoplastic lungs without CDH (N-CDH) and hypoplastic lungs with CDH (N+CDH). The pulmonary expression of NKCC-1, alpha-/beta-ENaC and Na/K-ATPase was then analyzed using Western blot. We found that the protein levels of NKCC-1 on gestational days E18 and E21 were significantly lower among fetuses with N+CDH as well as N-CDH compared to controls. The expression of beta-ENaC was also significantly down-regulated in both the groups on E18 and E21. The protein levels of alpha-ENaC and Na/K-ATPase were not found to be significantly decreased, but both showed a tendency towards down-regulation. The marked down-regulation of NKCC-1 in fetal hypoplastic lungs with CDH indicates a possibly decreased lung liquid production. This may be one of the mechanisms behind the disturbed pulmonary development in CDH. We also show that beta-ENaC is down-regulated. Down-regulation of beta-ENaC may result in abnormal lung liquid absorption, which could be one of the mechanisms behind the respiratory distress seen in CDH patients postpartum.
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Hernandez JM, Cox G, Janssen LJ. Involvement of the Neurokinin-2 Receptor in Airway Smooth Muscle Stretch-Activated Contractions Assessed in Perfused Intact Bovine Bronchial Segments. J Pharmacol Exp Ther 2008; 327:503-10. [DOI: 10.1124/jpet.108.141176] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
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Fairbank NJ, Connolly SC, Mackinnon JD, Wehry K, Deng L, Maksym GN. Airway smooth muscle cell tone amplifies contractile function in the presence of chronic cyclic strain. Am J Physiol Lung Cell Mol Physiol 2008; 295:L479-88. [PMID: 18586955 DOI: 10.1152/ajplung.00421.2007] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Chronic contractile activation, or tone, in asthma coupled with continuous stretching due to breathing may be involved in altering the contractile function of airway smooth muscle (ASM). Previously, we (11) showed that cytoskeletal remodeling and stiffening responses to acute (2 h) localized stresses were modulated by the level of contractile activation of ASM. Here, we investigated if altered contractility in response to chronic mechanical strain was dependent on repeated modulation of contractile tone. Cultured human ASM cells received 5% cyclic (0.3 Hz), predominantly uniaxial strain for 5 days, with once-daily dosing of either sham, forskolin, carbachol, or histamine to alter tone. Stiffness, contractility (KCl), and "relaxability" (forskolin) were then measured as was cell alignment, myosin light-chain phosphorylation (pMLC), and myosin light-chain kinase (MLCK) content. Cells became aligned and baseline stiffness increased with strain, but repeated lowering of tone inhibited both effects (P < 0.05). Strain also reversed a negative tone-modulation dependence of MLCK, observed in static conditions in agreement with previous reports, with strain and tone together increasing both MLCK and pMLC. Furthermore, contractility increased 176% (SE 59) with repeated tone elevation. These findings indicate that with strain, and not without, repeated tone elevation promoted contractile function through changes in cytoskeletal organization and increased contractile protein. The ability of repeated contractile activation to increase contractility, but only with mechanical stretching, suggests a novel mechanism for increased ASM contractility in asthma and for the role of continuous bronchodilator and corticosteroid therapy in reversing airway hyperresponsiveness.
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Affiliation(s)
- Nigel J Fairbank
- School of Biomedical Engineering, Dalhousie Univ., 5981 Univ. Ave., Halifax, Nova Scotia B3H 1W2, Canada
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23
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Development and evaluation of microdevices for studying anisotropic biaxial cyclic stretch on cells. Biomed Microdevices 2008; 10:869-882. [DOI: 10.1007/s10544-008-9201-8] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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24
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Expression of smooth muscle and extracellular matrix proteins in relation to airway function in asthma. J Allergy Clin Immunol 2008; 121:1196-202. [PMID: 18405955 DOI: 10.1016/j.jaci.2008.02.017] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2007] [Revised: 01/03/2008] [Accepted: 02/14/2008] [Indexed: 11/23/2022]
Abstract
BACKGROUND Smooth muscle content is increased within the airway wall in patients with asthma and is likely to play a role in airway hyperresponsiveness. However, smooth muscle cells express several contractile and structural proteins, and each of these proteins may influence airway function distinctly. OBJECTIVE We examined the expression of contractile and structural proteins of smooth muscle cells, as well as extracellular matrix proteins, in bronchial biopsies of patients with asthma, and related these to lung function, airway hyperresponsiveness, and responses to deep inspiration. METHODS Thirteen patients with asthma (mild persistent, atopic, nonsmoking) participated in this cross-sectional study. FEV(1)% predicted, PC(20) methacholine, and resistance of the respiratory system by the forced oscillation technique during tidal breathing and deep breath were measured. Within 1 week, a bronchoscopy was performed to obtain 6 bronchial biopsies that were immunohistochemically stained for alpha-SM-actin, desmin, myosin light chain kinase (MLCK), myosin, calponin, vimentin, elastin, type III collagen, and fibronectin. The level of expression was determined by automated densitometry. RESULTS PC(20) methacholine was inversely related to the expression of alpha-smooth muscle actin (r = -0.62), desmin (r = -0.56), and elastin (r = -0.78). In addition, FEV(1)% predicted was positively related and deep inspiration-induced bronchodilation inversely related to desmin (r = -0.60), MLCK (r = -0.60), and calponin (r = -0.54) expression. CONCLUSION Airway hyperresponsiveness, FEV(1)% predicted, and airway responses to deep inspiration are associated with selective expression of airway smooth muscle proteins and components of the extracellular matrix.
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25
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An S, Bai T, Bates J, Black J, Brown R, Brusasco V, Chitano P, Deng L, Dowell M, Eidelman D, Fabry B, Fairbank N, Ford L, Fredberg J, Gerthoffer W, Gilbert S, Gosens R, Gunst S, Halayko A, Ingram R, Irvin C, James A, Janssen L, King G, Knight D, Lauzon A, Lakser O, Ludwig M, Lutchen K, Maksym G, Martin J, Mauad T, McParland B, Mijailovich S, Mitchell H, Mitchell R, Mitzner W, Murphy T, Paré P, Pellegrino R, Sanderson M, Schellenberg R, Seow C, Silveira P, Smith P, Solway J, Stephens N, Sterk P, Stewart A, Tang D, Tepper R, Tran T, Wang L. Airway smooth muscle dynamics: a common pathway of airway obstruction in asthma. Eur Respir J 2007; 29:834-60. [PMID: 17470619 PMCID: PMC2527453 DOI: 10.1183/09031936.00112606] [Citation(s) in RCA: 279] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Excessive airway obstruction is the cause of symptoms and abnormal lung function in asthma. As airway smooth muscle (ASM) is the effecter controlling airway calibre, it is suspected that dysfunction of ASM contributes to the pathophysiology of asthma. However, the precise role of ASM in the series of events leading to asthmatic symptoms is not clear. It is not certain whether, in asthma, there is a change in the intrinsic properties of ASM, a change in the structure and mechanical properties of the noncontractile components of the airway wall, or a change in the interdependence of the airway wall with the surrounding lung parenchyma. All these potential changes could result from acute or chronic airway inflammation and associated tissue repair and remodelling. Anti-inflammatory therapy, however, does not "cure" asthma, and airway hyperresponsiveness can persist in asthmatics, even in the absence of airway inflammation. This is perhaps because the therapy does not directly address a fundamental abnormality of asthma, that of exaggerated airway narrowing due to excessive shortening of ASM. In the present study, a central role for airway smooth muscle in the pathogenesis of airway hyperresponsiveness in asthma is explored.
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Affiliation(s)
- S.S. An
- Division of Physiology, Dept of Environmental Health Sciences, Johns Hopkins University Bloomberg School of Public Health
| | - T.R. Bai
- James Hogg iCAPTURE Centre, University of British Columbia, Vancouver
| | - J.H.T. Bates
- Vermont Lung Center, University of Vermont College of Medicine, Burlington, VT
| | - J.L. Black
- Dept of Pharmacology, University of Sydney, Sydney
| | - R.H. Brown
- Dept of Anesthesiology and Critical Care medicine, Johns Hopkins Medical Institutions, Baltimore, MD
| | - V. Brusasco
- Dept of Internal Medicine, University of Genoa, Genoa
| | - P. Chitano
- Dept of Paediatrics, Duke University Medical Center, Durham, NC
| | - L. Deng
- Program in Molecular and Integrative Physiological Sciences, Dept of Environmental Health, Harvard School of Public Health
- Bioengineering College, Chongqing University, Chongqing, China
| | - M. Dowell
- Section of Pulmonary and Critical Care Medicine
| | - D.H. Eidelman
- Meakins-Christie Laboratories, Dept of Medicine, McGill University, Montreal
| | - B. Fabry
- Center for Medical Physics and Technology, Erlangen, Germany
| | - N.J. Fairbank
- School of Biomedical Engineering, Dalhousie University, Halifax
| | | | - J.J. Fredberg
- Program in Molecular and Integrative Physiological Sciences, Dept of Environmental Health, Harvard School of Public Health
| | - W.T. Gerthoffer
- Dept of Pharmacology, University of Nevada School of Medicine, Reno, NV
| | | | - R. Gosens
- Dept of Physiology, University of Manitoba, Winnipeg
| | - S.J. Gunst
- Dept of Physiology, Indiana University School of Medicine, Indianapolis, IN
| | - A.J. Halayko
- Dept of Physiology, University of Manitoba, Winnipeg
| | - R.H. Ingram
- Dept of Medicine, Emory University School of Medicine, Atlanta, GA
| | - C.G. Irvin
- Vermont Lung Center, University of Vermont College of Medicine, Burlington, VT
| | - A.L. James
- West Australian Sleep Disorders Research Institute, Sir Charles Gairdner Hospital, Nedlands
| | - L.J. Janssen
- Dept of Medicine, McMaster University, Hamilton, Canada
| | - G.G. King
- Woolcock Institute of Medical Research, Camperdown
| | - D.A. Knight
- James Hogg iCAPTURE Centre, University of British Columbia, Vancouver
| | - A.M. Lauzon
- Meakins-Christie Laboratories, Dept of Medicine, McGill University, Montreal
| | - O.J. Lakser
- Section of Paediatric Pulmonary Medicine, University of Chicago, Chicago, IL
| | - M.S. Ludwig
- Meakins-Christie Laboratories, Dept of Medicine, McGill University, Montreal
| | - K.R. Lutchen
- Dept of Biomedical Engineering, Boston University, Boston
| | - G.N. Maksym
- School of Biomedical Engineering, Dalhousie University, Halifax
| | - J.G. Martin
- Meakins-Christie Laboratories, Dept of Medicine, McGill University, Montreal
| | - T. Mauad
- Dept of Pathology, Sao Paulo University Medical School, Sao Paulo, Brazil
| | | | - S.M. Mijailovich
- Program in Molecular and Integrative Physiological Sciences, Dept of Environmental Health, Harvard School of Public Health
| | - H.W. Mitchell
- Discipline of Physiology, School of Biomedical, Biomolecular and Chemical Sciences, University of Western Australia, Perth
| | | | - W. Mitzner
- Division of Physiology, Dept of Environmental Health Sciences, Johns Hopkins University Bloomberg School of Public Health
| | - T.M. Murphy
- Dept of Paediatrics, Duke University Medical Center, Durham, NC
| | - P.D. Paré
- James Hogg iCAPTURE Centre, University of British Columbia, Vancouver
| | - R. Pellegrino
- Dept of Respiratory Physiopathology, S. Croce e Carle Hospital, Cuneo, Italy
| | - M.J. Sanderson
- Dept of Physiology, University of Massachusetts Medical School, Worcester, MA
| | - R.R. Schellenberg
- James Hogg iCAPTURE Centre, University of British Columbia, Vancouver
| | - C.Y. Seow
- James Hogg iCAPTURE Centre, University of British Columbia, Vancouver
| | - P.S.P. Silveira
- Dept of Pathology, Sao Paulo University Medical School, Sao Paulo, Brazil
| | - P.G. Smith
- Dept of Paediatrics, School of Medicine, Case Western Reserve University, Cleveland, OH
| | - J. Solway
- Section of Pulmonary and Critical Care Medicine
| | - N.L. Stephens
- Dept of Physiology, University of Manitoba, Winnipeg
| | - P.J. Sterk
- Dept of Pulmonology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - A.G. Stewart
- Dept of Pharmacology, University of Melbourne, Parkville, Australia
| | - D.D. Tang
- Center for Cardiovascular Sciences, Albany Medical College, Albany, NY, USA
| | - R.S. Tepper
- Dept of Paediatrics, Indiana University School of Medicine, Indianapolis, IN
| | - T. Tran
- Dept of Physiology, University of Manitoba, Winnipeg
| | - L. Wang
- Dept of Paediatrics, Duke University Medical Center, Durham, NC
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Chanez P, Wenzel SE, Anderson GP, Anto JM, Bel EH, Boulet LP, Brightling CE, Busse WW, Castro M, Dahlen B, Dahlen SE, Fabbri LM, Holgate ST, Humbert M, Gaga M, Joos GF, Levy B, Rabe KF, Sterk PJ, Wilson SJ, Vachier I. Severe asthma in adults: what are the important questions? J Allergy Clin Immunol 2007; 119:1337-48. [PMID: 17416409 DOI: 10.1016/j.jaci.2006.11.702] [Citation(s) in RCA: 203] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2006] [Revised: 11/10/2006] [Accepted: 11/15/2006] [Indexed: 12/18/2022]
Abstract
The term severe refractory asthma (SRA) in adults applies to patients who remain difficult to control despite extensive re-evaluation of diagnosis and management following an observational period of at least 6 months by a specialist. Factors that influence asthma control should be recognized and adequately addressed prior to confirming the diagnosis of SRA. This report presents statements according to the literature defining SRA in order address the important questions. Phenotyping SRA will improve our understanding of mechanisms, natural history, and prognosis. Female gender, obesity, and smoking are associated with SRA. Atopy is less frequent in SRA, but occupational sensitizers are common inducers of new-onset SRA. Viruses contribute to severe exacerbations and can persist in the airways for long periods. Inflammatory cells are in the airways of the majority of patients with SRA and persist despite steroid therapy. The T(H)2 immune process alone is inadequate to explain SRA. Reduced responsiveness to corticosteroids is common, and epithelial cell and smooth muscle abnormalities are found, contributing to airway narrowing. Large and small airway wall thickening is observed, but parenchymal abnormalities may influence airway limitation. Inhaled corticosteroids and bronchodilators are the mainstay of treatment, but patients with SRA remain uncontrolled, indicating a need for new therapies.
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Affiliation(s)
- Pascal Chanez
- INSERM U454 and Clinique des Maladies Respiratoires, Montpellier, France.
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