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Zimmermann R, Roeder F, Ruppert C, Smith BJ, Knudsen L. Low volume ventilation of pre-injured lungs degrades lung function via stress concentration and progressive alveolar collapse. Am J Physiol Lung Cell Mol Physiol 2024. [PMID: 38712429 DOI: 10.1152/ajplung.00323.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 04/22/2024] [Indexed: 05/08/2024] Open
Abstract
Mechanical ventilation can cause ventilation-induced lung injury (VILI). The concept of stress concentrations suggests that surfactant dysfunction-induced microatelectases might impose injurious stresses on adjacent, open alveoli and function as germinal centers for injury propagation. The aim of the present study was to quantify the histopathological pattern of VILI progression and to test the hypothesis that injury progresses at the interface between microatelectases and ventilated lung parenchyma during low positive end-expiratory pressure (PEEP) ventilation. Bleomycin was used to induce lung injury with microatelectases in rats. Lungs were then mechanically ventilated for up to 6 hours at PEEP=1cmH2O and compared to bleomycin treated group ventilated protectively with PEEP=5cmH2O to minimize microatelectases. Lung mechanics were measured during ventilation. Afterwards lungs were fixed at end-inspiration or end-expiration for design-based stereology. Prior to VILI, bleomycin challenge reduced the number of open alveoli (N(alvair,par)) by 29%. No differences between end-inspiration and end-expiration were observed. Collapsed alveoli clustered in areas with a radius up to 56 µm. After PEEP=5cmH2O ventilation for 6 hours, N(alvair,par) remained stable while PEEP=1cmH2O ventilation led to an additional loss of aerated alveoli by 26%, mainly due to collapse, with a small fraction partly edema filled. Alveolar loss strongly correlated to worsening of tissue elastance, quasi-static compliance and inspiratory capacity. The radius of areas of collapsed alveoli increased to 94 µm, suggesting growth of the microatelectases. These data provide evidence that alveoli become unstable in neighborhood of microatelectases which most likely occurs due to by stress concentration-induced local vascular leak and surfactant dysfunction.
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Affiliation(s)
- Richard Zimmermann
- Institute of Functional and Applied Anatomy, Medizinische Hochschule Hannover, Hannover, Germany
| | - Franziska Roeder
- Institute of Functional and Applied Anatomy, Medizinische Hochschule Hannover, Hannover, Germany
| | - Clemens Ruppert
- Institute of Medicine, University of Giessen, Giessen, Germany
| | - Bradford J Smith
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Lars Knudsen
- Institute of Functional and Applied Anatomy, Medizinische Hochschule Hannover, Hannover, Germany
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2
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Perlman CE, Knudsen L, Smith BJ. The fix is not yet in: recommendation for fixation of lungs within physiologic/pathophysiologic volume range in preclinical pulmonary structure-function studies. Am J Physiol Lung Cell Mol Physiol 2024. [PMID: 38712433 DOI: 10.1152/ajplung.00341.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 04/22/2024] [Indexed: 05/08/2024] Open
Abstract
Quantitative characterization of lung structures by morphometric or stereologic analysis of histologic sections is a powerful means of elucidating pulmonary structure-function relations. The overwhelming majority of studies, however, fix lungs for histology at pressures outside the physiologic/pathophysiologic respiratory volume range. Thus valuable information is being lost. In this perspective article, we argue that investigators performing pulmonary histologic studies should consider whether the aims of their studies would benefit from fixation at functional transpulmonary pressures, particular those of end-inspiration and end-expiration. We survey the pressures at which lungs are typically fixed in preclinical structure-function studies; provide examples of conditions that would benefit from histologic evaluation at functional lung volumes; summarize available fixation methods; discuss alternative imaging modalities; and discuss challenges to implementing the suggested approach and means of addressing those challenges. We aim to persuade investigators that modifying or complementing the traditional histologic approach by fixing lungs at minimal and maximal functional volumes could enable new understanding of pulmonary structure-function relations.
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Affiliation(s)
- Carrie E Perlman
- Department of Biomedical Engineering, Stevens Institute of Technology, Hoboken, NJ, United States
| | - Lars Knudsen
- Institute of Functional and Applied Anatomy, Medizinische Hochschule Hannover, Hannover, Germany
| | - Bradford J Smith
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
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3
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Agrawal DK, Smith BJ, Sottile PD, Hripcsak G, Albers DJ. Quantifiable identification of flow-limited ventilator dyssynchrony with the deformed lung ventilator model. Comput Biol Med 2024; 173:108349. [PMID: 38547660 DOI: 10.1016/j.compbiomed.2024.108349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 03/13/2024] [Accepted: 03/17/2024] [Indexed: 04/17/2024]
Abstract
BACKGROUND Ventilator dyssynchrony (VD) can worsen lung injury and is challenging to detect and quantify due to the complex variability in the dyssynchronous breaths. While machine learning (ML) approaches are useful for automating VD detection from the ventilator waveform data, scalable severity quantification and its association with pathogenesis and ventilator mechanics remain challenging. OBJECTIVE We develop a systematic framework to quantify pathophysiological features observed in ventilator waveform signals such that they can be used to create feature-based severity stratification of VD breaths. METHODS A mathematical model was developed to represent the pressure and volume waveforms of individual breaths in a feature-based parametric form. Model estimates of respiratory effort strength were used to assess the severity of flow-limited (FL)-VD breaths compared to normal breaths. A total of 93,007 breath waveforms from 13 patients were analyzed. RESULTS A novel model-defined continuous severity marker was developed and used to estimate breath phenotypes of FL-VD breaths. The phenotypes had a predictive accuracy of over 97% with respect to the previously developed ML-VD identification algorithm. To understand the incidence of FL-VD breaths and their association with the patient state, these phenotypes were further successfully correlated with ventilator-measured parameters and electronic health records. CONCLUSION This work provides a computational pipeline to identify and quantify the severity of FL-VD breaths and paves the way for a large-scale study of VD causes and effects. This approach has direct application to clinical practice and in meaningful knowledge extraction from the ventilator waveform data.
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Affiliation(s)
- Deepak K Agrawal
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra, 400076, India; Department of Bioengineering, University of Colorado Denver | Anschutz Medical Campus, Aurora, CO, 80045, USA.
| | - Bradford J Smith
- Department of Bioengineering, University of Colorado Denver | Anschutz Medical Campus, Aurora, CO, 80045, USA; Section of Pulmonary and Sleep Medicine, Department of Pediatrics, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Peter D Sottile
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado School of Medicine, Aurora, CO, 80045, USA
| | - George Hripcsak
- Department of Biomedical Informatics, Columbia University, New York, NY, 10027, USA
| | - David J Albers
- Department of Bioengineering, University of Colorado Denver | Anschutz Medical Campus, Aurora, CO, 80045, USA; Department of Biomedical Informatics, Columbia University, New York, NY, 10027, USA; Department of Biomedical Informatics, Univerisity of Colorado Anschutz Medical Campus, Aurora, CO 80045.
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4
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McGinn EA, Mandell EW, Smith BJ, Duke JW, Bush A, Abman SH. Reply to Tepper et al.: Additional Thoughts on Intrinsic Dysanapsis. Am J Respir Crit Care Med 2024; 209:1041-1042. [PMID: 38301260 DOI: 10.1164/rccm.202312-2345le] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2023] [Accepted: 01/31/2024] [Indexed: 02/03/2024] Open
Affiliation(s)
- Elizabeth A McGinn
- Pediatric Heart Lung Center, Department of Pediatrics
- Department of Pediatric Critical Care Medicine
| | - Erica W Mandell
- Pediatric Heart Lung Center, Department of Pediatrics
- Department of Neonatology
| | - Bradford J Smith
- Pediatric Heart Lung Center, Department of Pediatrics
- Department of Pediatric Pulmonary and Sleep Medicine, and
- Department of Bioengineering, Anschutz School of Medicine, University of Colorado-Denver, Aurora, Colorado
| | - Joseph W Duke
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona; and
| | - Andrew Bush
- Center for Pediatrics and Child Health, Imperial College of Medicine, London, United Kingdom
| | - Steven H Abman
- Pediatric Heart Lung Center, Department of Pediatrics
- Department of Pediatric Pulmonary and Sleep Medicine, and
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5
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Roeder F, Röpke T, Steinmetz LK, Kolb M, Maus UA, Smith BJ, Knudsen L. Exploring alveolar recruitability using positive end-expiratory pressure in mice overexpressing TGF-β1: a structure-function analysis. Sci Rep 2024; 14:8080. [PMID: 38582767 PMCID: PMC10998853 DOI: 10.1038/s41598-024-58213-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Accepted: 03/26/2024] [Indexed: 04/08/2024] Open
Abstract
Pre-injured lungs are prone to injury progression in response to mechanical ventilation. Heterogeneous ventilation due to (micro)atelectases imparts injurious strains on open alveoli (known as volutrauma). Hence, recruitment of (micro)atelectases by positive end-expiratory pressure (PEEP) is necessary to interrupt this vicious circle of injury but needs to be balanced against acinar overdistension. In this study, the lung-protective potential of alveolar recruitment was investigated and balanced against overdistension in pre-injured lungs. Mice, treated with empty vector (AdCl) or adenoviral active TGF-β1 (AdTGF-β1) were subjected to lung mechanical measurements during descending PEEP ventilation from 12 to 0 cmH2O. At each PEEP level, recruitability tests consisting of two recruitment maneuvers followed by repetitive forced oscillation perturbations to determine tissue elastance (H) and damping (G) were performed. Finally, lungs were fixed by vascular perfusion at end-expiratory airway opening pressures (Pao) of 20, 10, 5 and 2 cmH2O after a recruitment maneuver, and processed for design-based stereology to quantify derecruitment and distension. H and G were significantly elevated in AdTGF-β1 compared to AdCl across PEEP levels. H was minimized at PEEP = 5-8 cmH2O and increased at lower and higher PEEP in both groups. These findings correlated with increasing septal wall folding (= derecruitment) and reduced density of alveolar number and surface area (= distension), respectively. In AdTGF-β1 exposed mice, 27% of alveoli remained derecruited at Pao = 20 cmH2O. A further decrease in Pao down to 2 cmH2O showed derecruitment of an additional 1.1 million alveoli (48%), which was linked with an increase in alveolar size heterogeneity at Pao = 2-5 cmH2O. In AdCl, decreased Pao resulted in septal folding with virtually no alveolar collapse. In essence, in healthy mice alveoli do not derecruit at low PEEP ventilation. The potential of alveolar recruitability in AdTGF-β1 exposed mice is high. H is optimized at PEEP 5-8 cmH2O. Lower PEEP folds and larger PEEP stretches septa which results in higher H and is more pronounced in AdTGF-β1 than in AdCl. The increased alveolar size heterogeneity at Pao = 5 cmH2O argues for the use of PEEP = 8 cmH2O for lung protective mechanical ventilation in this animal model.
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Affiliation(s)
- Franziska Roeder
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany
| | - Tina Röpke
- Department of Experimental Pneumology, Hannover Medical School, Hannover, Germany
| | | | - Martin Kolb
- Department of Medicine, Firestone Institute for Respiratory Health, McMaster University, Hamilton, ON, Canada
| | - Ulrich A Maus
- Department of Experimental Pneumology, Hannover Medical School, Hannover, Germany
- Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Center for Lung Disease (DZL), Hannover, Germany
| | - Bradford J Smith
- Department of Bioengineering, College of Engineering Design and Computing, University of Colorado Denver|Anschutz Medical Campus, Aurora, CO, USA
- Department of Pediatric Pulmonary and Sleep Medicine, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Lars Knudsen
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany.
- Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Center for Lung Disease (DZL), Hannover, Germany.
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6
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McGinn EA, Bye E, Gonzalez T, Sosa A, Bilodeaux J, Seedorf G, Smith BJ, Abman SH, Mandell EW. Antenatal Endotoxin Induces Dysanapsis in Experimental Bronchopulmonary Dysplasia. Am J Respir Cell Mol Biol 2024; 70:283-294. [PMID: 38207120 DOI: 10.1165/rcmb.2023-0157oc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Accepted: 01/10/2024] [Indexed: 01/13/2024] Open
Abstract
Bronchopulmonary dysplasia (BPD), the chronic lung disease of prematurity, is characterized by impaired lung development with sustained functional abnormalities due to alterations of airways and the distal lung. Although clinical studies have shown striking associations between antenatal stress and BPD, little is known about the underlying pathogenetic mechanisms. Whether dysanapsis, the concept of discordant growth of the airways and parenchyma, contributes to late respiratory disease as a result of antenatal stress is unknown. We hypothesized that antenatal endotoxin (ETX) impairs juvenile lung function as a result of altered central airway and distal lung structure, suggesting the presence of dysanapsis in this preclinical BPD model. Fetal rats were exposed to intraamniotic ETX (10 μg) or saline solution (control) 2 days before term. We performed extensive structural and functional evaluation of the proximal airways and distal lung in 2-week-old rats. Distal lung structure was quantified by stereology. Conducting airway diameters were measured using micro-computed tomography. Lung function was assessed during invasive ventilation to quantify baseline mechanics, response to methacholine challenge, and spirometry. ETX-exposed pups exhibited distal lung simplification, decreased alveolar surface area, and decreased parenchyma-airway attachments. ETX-exposed pups exhibited decreased tracheal and second- and third-generation airway diameters. ETX increased respiratory system resistance and decreased lung compliance at baseline. Only Newtonian resistance, specific to large airways, exhibited increased methacholine reactivity in ETX-exposed pups compared with controls. ETX-exposed pups had a decreased ratio of FEV in 0.1 second to FVC and a normal FEV in 0.1 second, paralleling the clinical definition of dysanapsis. Antenatal ETX causes abnormalities of the central airways and distal lung growth, suggesting that dysanapsis contributes to abnormal lung function in juvenile rats.
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Affiliation(s)
- Elizabeth A McGinn
- Pediatric Heart Lung Center, Department of Pediatrics
- Department of Pediatric Critical Care Medicine
| | - Elisa Bye
- Pediatric Heart Lung Center, Department of Pediatrics
| | | | - Alexander Sosa
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Jill Bilodeaux
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | | | - Bradford J Smith
- Pediatric Heart Lung Center, Department of Pediatrics
- Department of Pediatric Pulmonary and Sleep Medicine, and
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Steven H Abman
- Pediatric Heart Lung Center, Department of Pediatrics
- Department of Pediatric Pulmonary and Sleep Medicine, and
| | - Erica W Mandell
- Pediatric Heart Lung Center, Department of Pediatrics
- Department of Neonatology, University of Colorado School of Medicine, Aurora, Colorado; and
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7
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Petronek MS, Bodeker KL, Lee CY, Teferi N, Eschbacher KL, Jones KA, Loeffler BT, Smith BJ, Buatti JM, Magnotta VA, Allen BG. Iron-based biomarkers for personalizing pharmacological ascorbate therapy in glioblastoma: insights from a phase 2 clinical trial. J Neurooncol 2024; 166:493-501. [PMID: 38285244 DOI: 10.1007/s11060-024-04571-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Accepted: 01/11/2024] [Indexed: 01/30/2024]
Abstract
BACKGROUND Pharmacological ascorbate (intravenous delivery reaching plasma concentrations ≈ 20 mM; P-AscH-) has emerged as a promising therapeutic strategy for glioblastoma. Recently, a single-arm phase 2 clinical trial demonstrated a significant increase in overall survival when P-AscH- was combined with temozolomide and radiotherapy. As P-AscH- relies on iron-dependent mechanisms, this study aimed to assess the predictive potential of both molecular and imaging-based iron-related markers to enhance the personalization of P-AscH- therapy in glioblastoma participants. METHODS Participants (n = 55) with newly diagnosed glioblastoma were enrolled in a phase 2 clinical trial conducted at the University of Iowa (NCT02344355). Tumor samples obtained during surgical resection were processed and stained for transferrin receptor and ferritin heavy chain expression. A blinded pathologist performed pathological assessment. Quantitative susceptibility mapping (QSM) measures were obtained from pre-radiotherapy MRI scans following maximal safe surgical resection. Circulating blood iron panels were evaluated prior to therapy through the University of Iowa Diagnostic Laboratory. RESULTS Through univariate analysis, a significant inverse association was observed between tumor transferrin receptor expression and overall and progression-free survival. QSM measures exhibited a significant, positive association with progression-free survival. Subjects were actively followed until disease progression and then were followed through chart review or clinical visits for overall survival. CONCLUSIONS This study analyzes iron-related biomarkers in the context of P-AscH- therapy for glioblastoma. Integrating molecular, systemic, and imaging-based markers offers a multifaceted approach to tailoring treatment strategies, thereby contributing to improved patient outcomes and advancing the field of glioblastoma therapy.
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Affiliation(s)
- M S Petronek
- Department of Radiation Oncology, Division of Free Radical and Radiation Biology, University of Iowa, Iowa City, IA, USA.
| | - K L Bodeker
- Department of Radiation Oncology, Division of Free Radical and Radiation Biology, University of Iowa, Iowa City, IA, USA
| | - C Y Lee
- Department of Radiology, University of Iowa, Iowa City, IA, USA
| | - N Teferi
- Department of Radiation Oncology, Division of Free Radical and Radiation Biology, University of Iowa, Iowa City, IA, USA
| | - K L Eschbacher
- Department of Pathology, University of Iowa, Iowa City, IA, USA
| | - K A Jones
- Department of Pathology, Division of Neuropathology, Duke University, Durham, NC, USA
| | - B T Loeffler
- Holden Comprehensive Cancer Center, University of Iowa, Iowa City, IA, USA
| | - B J Smith
- Department of Biostatistics, University of Iowa, Iowa City, IA, USA
| | - J M Buatti
- Department of Radiation Oncology, Division of Free Radical and Radiation Biology, University of Iowa, Iowa City, IA, USA
| | - V A Magnotta
- Department of Radiology, University of Iowa, Iowa City, IA, USA
| | - B G Allen
- Department of Radiation Oncology, Division of Free Radical and Radiation Biology, University of Iowa, Iowa City, IA, USA
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8
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Stroh J, Sottile PD, Wang Y, Smith BJ, Bennett TD, Moss M, Albers DJ. Identifying low-dimensional trajectories of mechanically-ventilated patient systems: Empirical phenotypes of joint patient+care processes to enhance temporal analysis in ARDS research. medRxiv 2023:2023.12.14.23299978. [PMID: 38168309 PMCID: PMC10760265 DOI: 10.1101/2023.12.14.23299978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Mechanically ventilated patients generate waveform data that corresponds to patient interaction with unnatural forcing. This breath information includes both patient and apparatus sources, imbuing data with broad heterogeneity resulting from ventilator settings, patient efforts, patient-ventilator dyssynchronies, injuries, and other clinical therapies. Lung-protective ventilator settings outlined in respiratory care protocols lack personalization, and the connections between clinical outcomes and injuries resulting from mechanical ventilation remain poorly understood. Intra- and inter-patient heterogeneity and the volume of data comprising lung-ventilator system (LVS) observations limit broader and longer-time analysis of such systems. This work presents a computational pipeline for resolving LVS systems by tracking the evolution of data-conditioned model parameters and ventilator information. For individuals, the method presents LVS trajectory in a manageable way through low-dimensional representation of phenotypic breath waveforms. More general phenotypes across patients are also developed by aggregating patient-personalized estimates with additional normalization. The effectiveness of this process is demonstrated through application to multi-day observational series of 35 patients, which reveals the complexity of changes in the LVS over time. Considerable variations in breath behavior independent of the ventilator are revealed, suggesting the need to incorporate care factors such as patient sedation and posture in future analysis. The pipeline also identifies structural similarity in pressure-volume (pV) loop characterizations at the cohort level. The design invites active learning to incorporate clinical practitioner expertise into various methodological stages and algorithm choices.
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Affiliation(s)
| | | | - Yanran Wang
- University of Colorado Denver Anschutz Medical Campus
| | | | | | - Marc Moss
- University of Colorado Anschutz Medical Campus
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9
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Mattson CL, Smith BJ. Modeling Ventilator-Induced Lung Injury and Neutrophil Infiltration to Infer Injury Interdependence. Ann Biomed Eng 2023; 51:2837-2852. [PMID: 37592044 PMCID: PMC10842244 DOI: 10.1007/s10439-023-03346-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 08/07/2023] [Indexed: 08/19/2023]
Abstract
Acute respiratory distress syndrome (ARDS) and ventilator-induced lung injury (VILI) are heterogeneous conditions. The spatiotemporal evolution of these heterogeneities is complex, and it is difficult to elucidate the mechanisms driving its progression. Through previous quantitative analyses, we explored the distributions of cellular injury and neutrophil infiltration in experimental VILI and discovered that VILI progression is characterized by both the formation of new injury in quasi-random locations and the expansion of existing injury clusters. Distributions of neutrophil infiltration do not correlate with cell injury progression and suggest a systemic response. To further examine the dynamics of VILI, we have developed a novel computational model that simulates damage (cellular injury progression and neutrophil infiltration) using a stochastic approach. Optimization of the model parameters to fit experimental data reveals that the range and strength of interdependence between existing and new damaged regions both increase as mechanical ventilation patterns become more injurious. The interdependence of cellular injury can be attributed to mechanical tethering forces, while the interdependence of neutrophils is likely due to longer-range cell signaling pathways.
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Affiliation(s)
- Courtney L Mattson
- Department of Bioengineering, University of Colorado Denver | Anschutz Medical Campus, 12705 E. Montview Blvd., Suite 100, Aurora, CO, 80045, USA
| | - Bradford J Smith
- Department of Bioengineering, University of Colorado Denver | Anschutz Medical Campus, 12705 E. Montview Blvd., Suite 100, Aurora, CO, 80045, USA.
- Pulmonary and Sleep Medicine, Department of Pediatrics, School of Medicine, University of Colorado, Aurora, CO, USA.
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10
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McGinn EA, Mandell EW, Smith BJ, Duke JW, Bush A, Abman SH. Dysanapsis as a Determinant of Lung Function in Development and Disease. Am J Respir Crit Care Med 2023; 208:956-963. [PMID: 37677135 PMCID: PMC10870865 DOI: 10.1164/rccm.202306-1120pp] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Accepted: 09/07/2023] [Indexed: 09/09/2023] Open
Affiliation(s)
| | - Erica W. Mandell
- Pediatric Heart Lung Center, Department of Pediatrics
- Department of Neonatology
| | - Bradford J. Smith
- Pediatric Heart Lung Center, Department of Pediatrics
- Department of Pediatric Pulmonary and Sleep Medicine, and
- Department of Bioengineering, Anschutz School of Medicine, University of Colorado–Denver, Aurora, Colorado
| | - Joseph W. Duke
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona; and
| | - Andrew Bush
- Center for Pediatrics and Child Health, Imperial College of Medicine, London, United Kingdom
| | - Steven H. Abman
- Pediatric Heart Lung Center, Department of Pediatrics
- Department of Pediatric Pulmonary and Sleep Medicine, and
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11
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Colvin KL, Nguyen K, Boncella KL, Goodman DM, Elliott RJ, Harral JW, Bilodeaux J, Smith BJ, Yeager ME. Lung and Heart Biology of the Dp16 Mouse Model of down Syndrome: Implications for Studying Cardiopulmonary Disease. Genes (Basel) 2023; 14:1819. [PMID: 37761959 PMCID: PMC10530394 DOI: 10.3390/genes14091819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 09/12/2023] [Accepted: 09/15/2023] [Indexed: 09/29/2023] Open
Abstract
(1) Background: We sought to investigate the baseline lung and heart biology of the Dp16 mouse model of Down syndrome (DS) as a prelude to the investigation of recurrent respiratory tract infection. (2) Methods: In controls vs. Dp16 mice, we compared peripheral blood cell and plasma analytes. We examined baseline gene expression in lungs and hearts for key parameters related to susceptibility of lung infection. We investigated lung and heart protein expression and performed lung morphometry. Finally, and for the first time each in a model of DS, we performed pulmonary function testing and a hemodynamic assessment of cardiac function. (3) Results: Dp16 mice circulate unique blood plasma cytokines and chemokines. Dp16 mouse lungs over-express the mRNA of triplicated genes, but not necessarily corresponding proteins. We found a sex-specific decrease in the protein expression of interferon α receptors, yet an increased signal transducer and activator of transcription (STAT)-3 and phospho-STAT3. Platelet-activating factor receptor protein was not elevated in Dp16 mice. The lungs of Dp16 mice showed increased stiffness and mean linear intercept and contained bronchus-associated lymphoid tissue. The heart ventricles of Dp16 mice displayed hypotonicity. Finally, Dp16 mice required more ketamine to achieve an anesthetized state. (4) Conclusions: The Dp16 mouse model of DS displays key aspects of lung heart biology akin to people with DS. As such, it has the potential to be an extremely valuable model of recurrent severe respiratory tract infection in DS.
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Affiliation(s)
- Kelley L. Colvin
- Linda Crnic Institute for Down Syndrome, University of Colorado, Aurora, CO 80045, USA (D.M.G.)
| | - Kathleen Nguyen
- Department of Bioengineering, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO 80045, USA; (K.N.); (K.L.B.); (R.J.E.); (J.B.); (B.J.S.)
| | - Katie L. Boncella
- Department of Bioengineering, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO 80045, USA; (K.N.); (K.L.B.); (R.J.E.); (J.B.); (B.J.S.)
| | - Desiree M. Goodman
- Linda Crnic Institute for Down Syndrome, University of Colorado, Aurora, CO 80045, USA (D.M.G.)
| | - Robert J. Elliott
- Department of Bioengineering, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO 80045, USA; (K.N.); (K.L.B.); (R.J.E.); (J.B.); (B.J.S.)
| | - Julie W. Harral
- Department of Medicine, University of Colorado, Aurora, CO 80045, USA;
| | - Jill Bilodeaux
- Department of Bioengineering, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO 80045, USA; (K.N.); (K.L.B.); (R.J.E.); (J.B.); (B.J.S.)
| | - Bradford J. Smith
- Department of Bioengineering, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO 80045, USA; (K.N.); (K.L.B.); (R.J.E.); (J.B.); (B.J.S.)
- Section of Pediatric Pulmonary and Sleep Medicine, Department of Pediatrics, School of Medicine, University of Colorado, Aurora, CO 80045, USA
| | - Michael E. Yeager
- Linda Crnic Institute for Down Syndrome, University of Colorado, Aurora, CO 80045, USA (D.M.G.)
- Department of Bioengineering, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO 80045, USA; (K.N.); (K.L.B.); (R.J.E.); (J.B.); (B.J.S.)
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12
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Bilodeaux J, Farooqi H, Osovskaya M, Sosa A, Wallbank A, Knudsen L, Sottile PD, Albers DJ, Smith BJ. Differential effects of two-hit models of acute and ventilator-induced lung injury on lung structure, function, and inflammation. Front Physiol 2023; 14:1217183. [PMID: 37565138 PMCID: PMC10410077 DOI: 10.3389/fphys.2023.1217183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 07/13/2023] [Indexed: 08/12/2023] Open
Abstract
Acute respiratory distress syndrome (ARDS) and acute lung injury have a diverse spectrum of causative factors including sepsis, aspiration of gastric contents, and near drowning. Clinical management of severe lung injury typically includes mechanical ventilation to maintain gas exchange which can lead to ventilator-induced lung injury (VILI). The cause of respiratory failure is acknowledged to affect the degree of lung inflammation, changes in lung structure, and the mechanical function of the injured lung. However, these differential effects of injury and the role of etiology in the structure-function relationship are not fully understood. To address this knowledge gap we caused lung injury with intratracheal hydrochloric acid (HCL) or endotoxin (LPS) 2 days prior to ventilation or with an injurious lavage (LAV) immediately prior to ventilation. These injury groups were then ventilated with high inspiratory pressures and positive end expiratory pressure (PEEP) = 0 cmH2O to cause VILI and model the clinical course of ARDS followed by supportive ventilation. The effects of injury were quantified using invasive lung function measurements recorded during PEEP ladders where the end-expiratory pressure was increased from 0 to 15 cm H2O and decreased back to 0 cmH2O in steps of 3 cmH2O. Design-based stereology was used to quantify the parenchymal structure of lungs air-inflated to 2, 5, and 10 cmH2O. Pro-inflammatory gene expression was measured with real-time quantitative polymerase chain reaction and alveolocapillary leak was estimated by measuring bronchoalveolar lavage protein content. The LAV group had small, stiff lungs that were recruitable at higher pressures, but did not demonstrate substantial inflammation. The LPS group showed septal swelling and high pro-inflammatory gene expression that was exacerbated by VILI. Despite widespread alveolar collapse, elastance in LPS was only modestly elevated above healthy mice (CTL) and there was no evidence of recruitability. The HCL group showed increased elastance and some recruitability, although to a lesser degree than LAV. Pro-inflammatory gene expression was elevated, but less than LPS, and the airspace dimensions were reduced. Taken together, those data highlight how different modes of injury, in combination with a 2nd hit of VILI, yield markedly different effects.
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Affiliation(s)
- Jill Bilodeaux
- Department of Bioengineering, University of Colorado Denver | Anschutz Medical Campus, Aurora, CO, United States
- Department of Microbiology, University of Colorado Denver/Anschutz Medical Campus, Aurora, Germany
| | - Huda Farooqi
- Department of Bioengineering, University of Colorado Denver | Anschutz Medical Campus, Aurora, CO, United States
| | - Maria Osovskaya
- Department of Bioengineering, University of Colorado Denver | Anschutz Medical Campus, Aurora, CO, United States
| | - Alexander Sosa
- Department of Bioengineering, University of Colorado Denver | Anschutz Medical Campus, Aurora, CO, United States
| | - Alison Wallbank
- Department of Bioengineering, University of Colorado Denver | Anschutz Medical Campus, Aurora, CO, United States
| | - Lars Knudsen
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany
- Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Centre for Lung Research (DZL), Hannover, Germany
| | - Peter D. Sottile
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado School of Medicine, Aurora, CO, United States
| | - David J. Albers
- Department of Bioengineering, University of Colorado Denver | Anschutz Medical Campus, Aurora, CO, United States
- Section of Informatics and Data Science, Department of Pediatrics, School of Medicine, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO, United States
| | - Bradford J. Smith
- Department of Bioengineering, University of Colorado Denver | Anschutz Medical Campus, Aurora, CO, United States
- Section of Pulmonary and Sleep Medicine, Department of Pediatrics, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO, United States
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13
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Wallbank AM, Vaughn AE, Niemiec S, Bilodeaux J, Lehmann T, Knudsen L, Kolanthai E, Seal S, Zgheib C, Nozik E, Liechty KW, Smith BJ. CNP-miR146a improves outcomes in a two-hit acute- and ventilator-induced lung injury model. Nanomedicine 2023; 50:102679. [PMID: 37116556 PMCID: PMC10129905 DOI: 10.1016/j.nano.2023.102679] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Revised: 03/21/2023] [Accepted: 04/09/2023] [Indexed: 04/30/2023]
Abstract
Acute respiratory distress syndrome (ARDS) has high mortality (~40 %) and requires the lifesaving intervention of mechanical ventilation. A variety of systemic inflammatory insults can progress to ARDS, and the inflamed and injured lung is susceptible to ventilator-induced lung injury (VILI). Strategies to mitigate the inflammatory response while restoring pulmonary function are limited, thus we sought to determine if treatment with CNP-miR146a, a conjugate of novel free radical scavenging cerium oxide nanoparticles (CNP) to the anti-inflammatory microRNA (miR)-146a, would protect murine lungs from acute lung injury (ALI) induced with intratracheal endotoxin and subsequent VILI. Lung injury severity and treatment efficacy were evaluated via lung mechanical function, relative gene expression of inflammatory biomarkers, and lung morphometry (stereology). CNP-miR146a reduced the severity of ALI and slowed the progression of VILI, evidenced by improvements in inflammatory biomarkers, atelectasis, gas volumes in the parenchymal airspaces, and the stiffness of the pulmonary system.
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Affiliation(s)
- Alison M Wallbank
- Department of Bioengineering, University of Colorado Denver | Anschutz Medical Campus, Aurora, CO, USA
| | - Alyssa E Vaughn
- Laboratory for Fetal and Regenerative Biology, Department of Surgery, University of Colorado Denver School of Medicine and Children's Hospital Colorado, Aurora, CO, USA
| | - Steve Niemiec
- Laboratory for Fetal and Regenerative Biology, Department of Surgery, University of Colorado Denver School of Medicine and Children's Hospital Colorado, Aurora, CO, USA
| | - Jill Bilodeaux
- Department of Bioengineering, University of Colorado Denver | Anschutz Medical Campus, Aurora, CO, USA
| | - Tanner Lehmann
- Laboratory for Fetal and Regenerative Biology, Department of Surgery, University of Colorado Denver School of Medicine and Children's Hospital Colorado, Aurora, CO, USA
| | - Lars Knudsen
- Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Centre for Lung Research (DZL), Hannover, Germany; Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Center for Lung Research, Germany
| | - Elayaraja Kolanthai
- Advanced Materials Processing and Analysis Center, Department of Materials Science and Engineering, University of Central Florida, Orlando, FL, USA
| | - Sudipta Seal
- Advanced Materials Processing and Analysis Center, Department of Materials Science and Engineering, University of Central Florida, Orlando, FL, USA
| | - Carlos Zgheib
- Laboratory for Fetal and Regenerative Biology, Department of Surgery, University of Colorado Denver School of Medicine and Children's Hospital Colorado, Aurora, CO, USA; Laboratory for Fetal and Regenerative Biology, Department of Surgery, University of Arizona Tucson College of Medicine and Banner Children's at Diamond Children's Medical Center, Tucson, AZ, USA
| | - Eva Nozik
- Developmental Lung Biology, Cardiovascular Pulmonary Research Laboratories, Division of Pulmonary Sciences and Critical Care Medicine, Division of Pediatric Critical Care, Departments of Medicine and Pediatrics, University of Colorado, Aurora, CO, USA
| | - Kenneth W Liechty
- Laboratory for Fetal and Regenerative Biology, Department of Surgery, University of Colorado Denver School of Medicine and Children's Hospital Colorado, Aurora, CO, USA; Laboratory for Fetal and Regenerative Biology, Department of Surgery, University of Arizona Tucson College of Medicine and Banner Children's at Diamond Children's Medical Center, Tucson, AZ, USA
| | - Bradford J Smith
- Department of Bioengineering, University of Colorado Denver | Anschutz Medical Campus, Aurora, CO, USA; Department of Pediatric Pulmonary and Sleep Medicine, School of Medicine, University of Colorado, Aurora, CO, USA.
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14
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Knudsen L, Hummel B, Wrede C, Zimmermann R, Perlman CE, Smith BJ. Acinar micromechanics in health and lung injury: what we have learned from quantitative morphology. Front Physiol 2023; 14:1142221. [PMID: 37025383 PMCID: PMC10070844 DOI: 10.3389/fphys.2023.1142221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 03/09/2023] [Indexed: 04/08/2023] Open
Abstract
Within the pulmonary acini ventilation and blood perfusion are brought together on a huge surface area separated by a very thin blood-gas barrier of tissue components to allow efficient gas exchange. During ventilation pulmonary acini are cyclically subjected to deformations which become manifest in changes of the dimensions of both alveolar and ductal airspaces as well as the interalveolar septa, composed of a dense capillary network and the delicate tissue layer forming the blood-gas barrier. These ventilation-related changes are referred to as micromechanics. In lung diseases, abnormalities in acinar micromechanics can be linked with injurious stresses and strains acting on the blood-gas barrier. The mechanisms by which interalveolar septa and the blood-gas barrier adapt to an increase in alveolar volume have been suggested to include unfolding, stretching, or changes in shape other than stretching and unfolding. Folding results in the formation of pleats in which alveolar epithelium is not exposed to air and parts of the blood-gas barrier are folded on each other. The opening of a collapsed alveolus (recruitment) can be considered as an extreme variant of septal wall unfolding. Alveolar recruitment can be detected with imaging techniques which achieve light microscopic resolution. Unfolding of pleats and stretching of the blood-gas barrier, however, require electron microscopic resolution to identify the basement membrane. While stretching results in an increase of the area of the basement membrane, unfolding of pleats and shape changes do not. Real time visualization of these processes, however, is currently not possible. In this review we provide an overview of septal wall micromechanics with focus on unfolding/folding as well as stretching. At the same time we provide a state-of-the-art design-based stereology methodology to quantify microarchitecture of alveoli and interalveolar septa based on different imaging techniques and design-based stereology.
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Affiliation(s)
- Lars Knudsen
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany
- Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Centre for Lung Research (DZL), Hannover, Germany
| | - Benjamin Hummel
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany
| | - Christoph Wrede
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany
- Research Core Unit Electron Microscopy, Hannover Medical School, Hannover, Germany
| | - Richard Zimmermann
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany
| | - Carrie E Perlman
- Department of Biomedical Engineering, Stevens Institute of Technology, Hoboken, NJ, United States
| | - Bradford J Smith
- Department of Bioengineering, College of Engineering Design and Computing, University of Colorado Denver | Anschutz Medical Campus, Aurora, CO, United States
- Department of Pediatric Pulmonary and Sleep Medicine, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
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15
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Neelakantan S, Ismail MK, Mukherjee T, Smith BJ, Rizi R, Avazmohammadi R. Volumetric versus distortional deformation in rat lungs. Proc SPIE Int Soc Opt Eng 2023; 12466:124661R. [PMID: 37565032 PMCID: PMC10414622 DOI: 10.1117/12.2653648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
There are several lung diseases that lead to alterations in regional lung mechanics, including acute respiratory distress syndrome. Such alterations can lead to localized underventilation of the affected areas resulting in the overdistension of the surrounding healthy regions. They can also lead to the surrounding alveoli expanding unevenly or distorting. Therefore, the quantification of the regional deformation in the lungs offers insights into identifying the regions at risk of lung injury. Although few recent studies have developed image processing techniques to quantify the regional volumetric deformation in the lung from dynamic imaging, the presence and extent of distortional deformation in the lung, and its correlation with volumetric deformation, remain poorly understood. In this study, we present a method that uses the four-dimensional displacement field obtained from image registration to quantify both regional volumetric and distortional deformation in the lung. We used dynamic computed tomography scans in a healthy rat over the course of one respiratory cycle in free breathing. Non-rigid image registration was performed to quantify voxel displacement during respiration. The deformation gradient was calculated using the displacement field and its determinant was used to quantify regional volumetric deformation. Regional distortion was calculated as the ratio of maximum to minimum principal stretches using the isochoric part of the Cauchy green tensor. We found an inverse correlation between volumetric strains and distortion indicating that poorly expanding alveoli tend to experience larger distortion. The combination of regional volumetric strains and distortion may serve as high-fidelity biomarkers to identify the regions at risk of most adverse lung injuries.
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Affiliation(s)
- Sunder Neelakantan
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, USA
| | - Mostafa K Ismail
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Tanmay Mukherjee
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, USA
| | - Bradford J Smith
- Department of Bioengineering, University of Colorado Denver | Anschutz Medical Campus, Aurora, CO, USA
- Department of Pediatric Pulmonary and Sleep Medicine, School of Medicine, University of Colorado, Aurora, CO, USA
| | - Rahim Rizi
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Reza Avazmohammadi
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, USA
- J. Mike Walker '66 Department of Mechanical Engineering, Texas A&M University, College Station, TX, USA
- Department of Cardiovascular Sciences, Houston Methodist Academic Institute, Houston, TX, USA
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16
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Stroh JN, Smith BJ, Sottile PD, Hripcsak G, Albers DJ. Hypothesis-driven modeling of the human lung-ventilator system: A characterization tool for Acute Respiratory Distress Syndrome research. J Biomed Inform 2023; 137:104275. [PMID: 36572279 PMCID: PMC9788853 DOI: 10.1016/j.jbi.2022.104275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 11/21/2022] [Accepted: 12/14/2022] [Indexed: 12/25/2022]
Abstract
Mechanical ventilation is an essential tool in the management of Acute Respiratory Distress Syndrome (ARDS), but it exposes patients to the risk of ventilator-induced lung injury (VILI). The human lung-ventilator system (LVS) involves the interaction of complex anatomy with a mechanical apparatus, which limits the ability of process-based models to provide individualized clinical support. This work proposes a hypothesis-driven strategy for LVS modeling in which robust personalization is achieved using a pre-defined parameter basis in a non-physiological model. Model inversion, here via windowed data assimilation, forges observed waveforms into interpretable parameter values that characterize the data rather than quantifying physiological processes. Accurate, model-based inference on human-ventilator data indicates model flexibility and utility over a variety of breath types, including those from dyssynchronous LVSs. Estimated parameters generate static characterizations of the data that are 50%-70% more accurate than breath-wise single-compartment model estimates. They also retain sufficient information to distinguish between the types of breath they represent. However, the fidelity and interpretability of model characterizations are tied to parameter definitions and model resolution. These additional factors must be considered in conjunction with the objectives of specific applications, such as identifying and tracking the development of human VILI.
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Affiliation(s)
- J N Stroh
- Department of Biomedical Informatics, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, CO, USA; Department of Bioengineering, University of Colorado, Denver-Anschutz Medical Campus, Aurora, CO, USA.
| | - Bradford J Smith
- Department of Bioengineering, University of Colorado, Denver-Anschutz Medical Campus, Aurora, CO, USA; Section of Pulmonary and Sleep Medicine, Department of Pediatrics, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, CO, USA
| | - Peter D Sottile
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, CO, USA
| | - George Hripcsak
- Department of Biomedical Informatics, Columbia University, New York, NY, USA
| | - David J Albers
- Department of Biomedical Informatics, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, CO, USA; Department of Bioengineering, University of Colorado, Denver-Anschutz Medical Campus, Aurora, CO, USA; Department of Biomedical Informatics, Columbia University, New York, NY, USA; Section of Informatics and Data Science, Department of Pediatrics, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, CO, USA
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17
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Hume PS, McClendon J, Kopf KW, Harral JW, Poczobutt JM, McCubbrey AL, Smith BJ, Henson PM, Majka SM, Petrache I, Janssen WJ. Cigarette smoke-induced airspace disease in mice develops independently of HIF-1α signaling in leukocytes. Am J Physiol Lung Cell Mol Physiol 2022; 323:L391-L399. [PMID: 35943156 PMCID: PMC9484987 DOI: 10.1152/ajplung.00491.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 07/21/2022] [Accepted: 08/01/2022] [Indexed: 11/22/2022] Open
Abstract
The pathogenesis of chronic obstructive pulmonary disease (COPD), a prevalent disease primarily caused by cigarette smoke exposure, is incompletely elucidated. Studies in humans and mice have suggested that hypoxia-inducible factor-1α (HIF-1α) may play a role. Reduced lung levels of HIF-1α are associated with decreased vascular density, whereas increased leukocyte HIF-1α may be responsible for increased inflammation. To elucidate the specific role of leukocyte HIF-1α in COPD, we exposed transgenic mice with conditional deletion or overexpression of HIF-1α in leukocytes to cigarette smoke for 7 mo. Outcomes included pulmonary physiology, aerated lung volumes via microcomputed tomography, lung morphometry and histology, and cardiopulmonary hemodynamics. On aggregate, cigarette smoke increased the aerated lung volume, quasi-static lung compliance, inspiratory capacity of all strains while reducing the total alveolar septal volume. Independent of smoke exposure, mice with leukocyte-specific HIF-1α overexpression had increased quasi-static compliance, inspiratory capacity, and alveolar septal volume compared with mice with leukocyte-specific HIF-1α deletion. However, the overall development of cigarette smoke-induced lung disease did not vary relative to control mice for either of the conditional strains. This suggests that the development of murine cigarette smoke-induced airspace disease occurs independently of leukocyte HIF-1α signaling.
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Affiliation(s)
- Patrick S Hume
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, National Jewish Health, Denver, Colorado
- Department of Medicine, University of Colorado, Aurora, Colorado
| | - Jazalle McClendon
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, National Jewish Health, Denver, Colorado
| | - Katrina W Kopf
- Biological Resource Center, National Jewish Health, Denver, Colorado
| | - Julie W Harral
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, National Jewish Health, Denver, Colorado
- Department of Medicine, University of Colorado, Aurora, Colorado
| | - Joanna M Poczobutt
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, National Jewish Health, Denver, Colorado
| | - Alexandra L McCubbrey
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, National Jewish Health, Denver, Colorado
- Department of Medicine, University of Colorado, Aurora, Colorado
| | - Bradford J Smith
- Department of Bioengineering, University of Colorado, Aurora, Colorado
| | - Peter M Henson
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, National Jewish Health, Denver, Colorado
- Department of Medicine, University of Colorado, Aurora, Colorado
| | - Susan M Majka
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, National Jewish Health, Denver, Colorado
- Gates Center for Regenerative Medicine and Stem Cell Biology, University of Colorado, Aurora, Colorado
| | - Irina Petrache
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, National Jewish Health, Denver, Colorado
- Department of Medicine, University of Colorado, Aurora, Colorado
| | - William J Janssen
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, National Jewish Health, Denver, Colorado
- Department of Medicine, University of Colorado, Aurora, Colorado
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18
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Mattson CL, Okamura K, Hume PS, Smith BJ. Spatiotemporal distribution of cellular injury and leukocytes during the progression of ventilator-induced lung injury. Am J Physiol Lung Cell Mol Physiol 2022; 323:L281-L296. [PMID: 35700201 PMCID: PMC9423727 DOI: 10.1152/ajplung.00207.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 05/26/2022] [Accepted: 06/12/2022] [Indexed: 11/22/2022] Open
Abstract
Supportive mechanical ventilation is a necessary lifesaving treatment for acute respiratory distress syndrome (ARDS). This intervention often leads to injury exacerbation by ventilator-induced lung injury (VILI). Patterns of injury in ARDS and VILI are recognized to be heterogeneous; however, quantification of these injury distributions remains incomplete. Developing a more detailed understanding of injury heterogeneity, particularly how it varies in space and time, can help elucidate the mechanisms of VILI pathogenesis. Ultimately, this knowledge can be used to develop protective ventilation strategies that slow disease progression. To expand existing knowledge of VILI heterogeneity, we document the spatial evolution of cellular injury distribution and leukocyte infiltration, on the micro- and macroscales, during protective and injurious mechanical ventilation. We ventilated naïve mice using either high inspiratory pressure and zero positive end-expiratory pressure ventilation or low tidal volume with positive end-expiratory pressure. Distributions of cellular injury, identified with propidium iodide staining, were microscopically analyzed at three levels of injury severity. Cellular injury initiated in diffuse, quasi-random patterns, and progressed through expansion of high-density regions of injured cells termed "injury clusters." The density profile of the expanding injury regions suggests that stress shielding occurs, protecting the already injured regions from further damage. Spatial distribution of leukocytes did not correlate with that of cellular injury or ventilation-induced changes in lung function. These results suggest that protective ventilation protocols should protect the interface between healthy and injured regions to stymie injury propagation.
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Affiliation(s)
- Courtney L Mattson
- Department of Bioengineering, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado
| | - Kayo Okamura
- Department of Bioengineering, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado
| | - Patrick S Hume
- Department of Pulmonary, Critical Care, and Sleep Medicine, National Jewish Health, Denver, Colorado
- Department of Pediatrics, Pulmonary and Sleep Medicine, School of Medicine, University of Colorado, Aurora, Colorado
| | - Bradford J Smith
- Department of Bioengineering, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado
- Department of Pediatrics, Pulmonary and Sleep Medicine, School of Medicine, University of Colorado, Aurora, Colorado
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19
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Saleh KS, Hewawasam R, Šerbedžija P, Blomberg R, Noreldeen SE, Edelman B, Smith BJ, Riches DWH, Magin CM. Engineering Hybrid-Hydrogels Comprised of Healthy or Diseased Decellularized Extracellular Matrix to Study Pulmonary Fibrosis. Cell Mol Bioeng 2022; 15:505-519. [PMID: 36444345 PMCID: PMC9700547 DOI: 10.1007/s12195-022-00726-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 06/10/2022] [Indexed: 11/25/2022] Open
Abstract
Idiopathic pulmonary fibrosis is a chronic disease characterized by progressive lung scarring that inhibits gas exchange. Evidence suggests fibroblast-matrix interactions are a prominent driver of disease. However, available preclinical models limit our ability to study these interactions. We present a technique for synthesizing phototunable poly(ethylene glycol) (PEG)-based hybrid-hydrogels comprising healthy or fibrotic decellularized extracellular matrix (dECM) to decouple mechanical properties from composition and elucidate their roles in fibroblast activation. Here, we engineered and characterized phototunable hybrid-hydrogels using molecular techniques such as ninhydrin and Ellman's assays to assess dECM functionalization, and parallel-plate rheology to measure hydrogel mechanical properties. These biomaterials were employed to investigate the activation of fibroblasts from dual-transgenic Col1a1-GFP and αSMA-RFP reporter mice in response to changes in composition and mechanical properties. We show that reacting functionalized dECM from healthy or bleomycin-injured mouse lungs with PEG alpha-methacrylate (αMA) in an off-stoichiometry Michael-addition reaction created soft hydrogels mimicking a healthy lung elastic modulus (4.99 ± 0.98 kPa). Photoinitiated stiffening increased the material modulus to fibrotic values (11.48 ± 1.80 kPa). Percent activation of primary murine fibroblasts expressing Col1a1 and αSMA increased by approximately 40% following dynamic stiffening of both healthy and bleomycin hybrid-hydrogels. There were no significant differences between fibroblast activation on stiffened healthy versus stiffened bleomycin-injured hybrid-hydrogels. Phototunable hybrid-hydrogels provide an important platform for probing cell-matrix interactions and developing a deeper understanding of fibrotic activation in pulmonary fibrosis. Our results suggest that mechanical properties are a more significant contributor to fibroblast activation than biochemical composition within the scope of the hybrid-hydrogel platform evaluated in this study. Supplementary Information The online version contains supplementary material available at 10.1007/s12195-022-00726-y.
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Affiliation(s)
- Kamiel S. Saleh
- Department of Bioengineering, University of Colorado, Denver | Anschutz Medical Campus, 2115 N Scranton Street, Suite 3010, Aurora, CO 80045 USA
| | - Rukshika Hewawasam
- Department of Bioengineering, University of Colorado, Denver | Anschutz Medical Campus, 2115 N Scranton Street, Suite 3010, Aurora, CO 80045 USA
| | - Predrag Šerbedžija
- Department of Bioengineering, University of Colorado, Denver | Anschutz Medical Campus, 2115 N Scranton Street, Suite 3010, Aurora, CO 80045 USA
| | - Rachel Blomberg
- Department of Bioengineering, University of Colorado, Denver | Anschutz Medical Campus, 2115 N Scranton Street, Suite 3010, Aurora, CO 80045 USA
| | - Saif E. Noreldeen
- Department of Bioengineering, University of Colorado, Denver | Anschutz Medical Campus, 2115 N Scranton Street, Suite 3010, Aurora, CO 80045 USA
| | - Benjamin Edelman
- Program in Cell Biology, Department of Pediatrics, National Jewish Health, Denver, CO USA
| | - Bradford J. Smith
- Department of Bioengineering, University of Colorado, Denver | Anschutz Medical Campus, 2115 N Scranton Street, Suite 3010, Aurora, CO 80045 USA
- Department of Pediatrics, University of Colorado, Anschutz Medical Campus, Aurora, CO USA
| | - David W. H. Riches
- Program in Cell Biology, Department of Pediatrics, National Jewish Health, Denver, CO USA
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado, Anschutz Medical Campus, Aurora, CO USA
- Department of Research, Veterans Affairs Eastern Colorado Health Care System, Aurora, CO USA
- Department of Immunology and Microbiology, University of Colorado, Anschutz Medical Campus, Aurora, CO USA
| | - Chelsea M. Magin
- Department of Bioengineering, University of Colorado, Denver | Anschutz Medical Campus, 2115 N Scranton Street, Suite 3010, Aurora, CO 80045 USA
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado, Anschutz Medical Campus, Aurora, CO USA
- Department of Pediatrics, University of Colorado, Anschutz Medical Campus, Aurora, CO USA
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20
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Abstract
Computational modelling of the lungs is an active field of study that integrates computational advances with lung biophysics, biomechanics, physiology and medical imaging to promote individualized diagnosis, prognosis and therapy evaluation in lung diseases. The complex and hierarchical architecture of the lung offers a rich, but also challenging, research area demanding a cross-scale understanding of lung mechanics and advanced computational tools to effectively model lung biomechanics in both health and disease. Various approaches have been proposed to study different aspects of respiration, ranging from compartmental to discrete micromechanical and continuum representations of the lungs. This article reviews several developments in computational lung modelling and how they are integrated with preclinical and clinical data. We begin with a description of lung anatomy and how different tissue components across multiple length scales affect lung mechanics at the organ level. We then review common physiological and imaging data acquisition methods used to inform modelling efforts. Building on these reviews, we next present a selection of model-based paradigms that integrate data acquisitions with modelling to understand, simulate and predict lung dynamics in health and disease. Finally, we highlight possible future directions where computational modelling can improve our understanding of the structure–function relationship in the lung.
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Affiliation(s)
- Sunder Neelakantan
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, USA
| | - Yi Xin
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Donald P. Gaver
- Department of Biomedical Engineering, Tulane University, New Orleans, LA, USA
| | - Maurizio Cereda
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Rahim Rizi
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Bradford J. Smith
- Department of Bioengineering, University of Colorado Denver
- Anschutz Medical Campus, Aurora, CO, USA
- Department of Pediatric Pulmonary and Sleep Medicine, School of Medicine, University of Colorado, Aurora, CO, USA
| | - Reza Avazmohammadi
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, USA
- J. Mike Walker '66 Department of Mechanical Engineering, Texas A&M University, College Station, TX, USA
- Department of Cardiovascular Sciences, Houston Methodist Academic Institute, Houston, TX, USA
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21
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Rizzo AN, Haeger SM, Oshima K, Yang Y, Wallbank AM, Jin Y, Lettau M, McCaig LA, Wickersham NE, McNeil JB, Zakharevich I, McMurtry SA, Langouët-Astrié CJ, Kopf KW, Voelker DR, Hansen KC, Shaver CM, Kerchberger VE, Peterson RA, Kuebler WM, Ochs M, Veldhuizen RA, Smith BJ, Ware LB, Bastarache JA, Schmidt EP. Alveolar epithelial glycocalyx degradation mediates surfactant dysfunction and contributes to acute respiratory distress syndrome. JCI Insight 2022; 7:154573. [PMID: 34874923 PMCID: PMC8855818 DOI: 10.1172/jci.insight.154573] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 12/03/2021] [Indexed: 12/03/2022] Open
Abstract
Acute respiratory distress syndrome (ARDS) is a common cause of respiratory failure yet has few pharmacologic therapies, reflecting the mechanistic heterogeneity of lung injury. We hypothesized that damage to the alveolar epithelial glycocalyx, a layer of glycosaminoglycans interposed between the epithelium and surfactant, contributes to lung injury in patients with ARDS. Using mass spectrometry of airspace fluid noninvasively collected from mechanically ventilated patients, we found that airspace glycosaminoglycan shedding (an index of glycocalyx degradation) occurred predominantly in patients with direct lung injury and was associated with duration of mechanical ventilation. Male patients had increased shedding, which correlated with airspace concentrations of matrix metalloproteinases. Selective epithelial glycocalyx degradation in mice was sufficient to induce surfactant dysfunction, a key characteristic of ARDS, leading to microatelectasis and decreased lung compliance. Rapid colorimetric quantification of airspace glycosaminoglycans was feasible and could provide point-of-care prognostic information to clinicians and/or be used for predictive enrichment in clinical trials.
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Affiliation(s)
- Alicia N. Rizzo
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine
| | - Sarah M. Haeger
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine
| | - Kaori Oshima
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine
| | - Yimu Yang
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine
| | | | - Ying Jin
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine,,Department of Biostatistics and Informatics, School of Public Health, University of Colorado, Aurora, Colorado, USA
| | - Marie Lettau
- Institute of Functional Anatomy, Charité-Universitätsmedizin, Berlin, Germany
| | - Lynda A. McCaig
- Department of Physiology and Pharmacology, Western University, London, Ontario, Canada
| | - Nancy E. Wickersham
- Department of Medicine and Department of Pathology, Microbiology and Immunology, Vanderbilt University, Nashville, Tennessee, USA
| | - J. Brennan McNeil
- Department of Medicine and Department of Pathology, Microbiology and Immunology, Vanderbilt University, Nashville, Tennessee, USA
| | - Igor Zakharevich
- Department of Biochemistry and Molecular Genetics, University of Colorado, Aurora, Colorado, USA
| | - Sarah A. McMurtry
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine
| | | | - Katrina W. Kopf
- Department of Medicine, National Jewish Health, Denver, Colorado, USA
| | - Dennis R. Voelker
- Department of Medicine, National Jewish Health, Denver, Colorado, USA
| | - Kirk C. Hansen
- Department of Biochemistry and Molecular Genetics, University of Colorado, Aurora, Colorado, USA
| | - Ciara M. Shaver
- Department of Medicine and Department of Pathology, Microbiology and Immunology, Vanderbilt University, Nashville, Tennessee, USA
| | - V. Eric Kerchberger
- Department of Medicine and Department of Pathology, Microbiology and Immunology, Vanderbilt University, Nashville, Tennessee, USA
| | - Ryan A. Peterson
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine,,Department of Biostatistics and Informatics, School of Public Health, University of Colorado, Aurora, Colorado, USA
| | | | - Matthias Ochs
- Institute of Functional Anatomy, Charité-Universitätsmedizin, Berlin, Germany
| | - Ruud A.W. Veldhuizen
- Department of Physiology and Pharmacology, Western University, London, Ontario, Canada
| | - Bradford J. Smith
- Department of Bioengineering, and,Division of Pulmonary and Sleep Medicine, Department of Pediatrics, University of Colorado, Aurora, Colorado, USA
| | - Lorraine B. Ware
- Department of Medicine and Department of Pathology, Microbiology and Immunology, Vanderbilt University, Nashville, Tennessee, USA
| | - Julie A. Bastarache
- Department of Medicine and Department of Pathology, Microbiology and Immunology, Vanderbilt University, Nashville, Tennessee, USA
| | - Eric P. Schmidt
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine,,Department of Medicine, Denver Health Medical Center, Denver, Colorado, USA
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22
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Agrawal DK, Smith BJ, Sottile PD, Albers DJ. A Damaged-Informed Lung Ventilator Model for Ventilator Waveforms. Front Physiol 2021; 12:724046. [PMID: 34658911 PMCID: PMC8517122 DOI: 10.3389/fphys.2021.724046] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 09/01/2021] [Indexed: 12/31/2022] Open
Abstract
Motivated by a desire to understand pulmonary physiology, scientists have developed physiological lung models of varying complexity. However, pathophysiology and interactions between human lungs and ventilators, e.g., ventilator-induced lung injury (VILI), present challenges for modeling efforts. This is because the real-world pressure and volume signals may be too complex for simple models to capture, and while complex models tend not to be estimable with clinical data, limiting clinical utility. To address this gap, in this manuscript we developed a new damaged-informed lung ventilator (DILV) model. This approach relies on mathematizing ventilator pressure and volume waveforms, including lung physiology, mechanical ventilation, and their interaction. The model begins with nominal waveforms and adds limited, clinically relevant, hypothesis-driven features to the waveform corresponding to pulmonary pathophysiology, patient-ventilator interaction, and ventilator settings. The DILV model parameters uniquely and reliably recapitulate these features while having enough flexibility to reproduce commonly observed variability in clinical (human) and laboratory (mouse) waveform data. We evaluate the proof-in-principle capabilities of our modeling approach by estimating 399 breaths collected for differently damaged lungs for tightly controlled measurements in mice and uncontrolled human intensive care unit data in the absence and presence of ventilator dyssynchrony. The cumulative value of mean squares error for the DILV model is, on average, ≈12 times less than the single compartment lung model for all the waveforms considered. Moreover, changes in the estimated parameters correctly correlate with known measures of lung physiology, including lung compliance as a baseline evaluation. Our long-term goal is to use the DILV model for clinical monitoring and research studies by providing high fidelity estimates of lung state and sources of VILI with an end goal of improving management of VILI and acute respiratory distress syndrome.
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Affiliation(s)
- Deepak K. Agrawal
- Department of Bioengineering, University of Colorado Denver|Anschutz Medical Campus, Aurora, CO, United States
- Section of Informatics and Data Science, Department of Pediatrics, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Bradford J. Smith
- Department of Bioengineering, University of Colorado Denver|Anschutz Medical Campus, Aurora, CO, United States
- Section of Pulmonary and Sleep Medicine, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Peter D. Sottile
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado School of Medicine, Aurora, CO, United States
| | - David J. Albers
- Department of Bioengineering, University of Colorado Denver|Anschutz Medical Campus, Aurora, CO, United States
- Section of Informatics and Data Science, Department of Pediatrics, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
- Department of Biomedical Informatics, Columbia University, New York, NY, United States
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23
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Stancil IT, Michalski JE, Davis-Hall D, Chu HW, Park JA, Magin CM, Yang IV, Smith BJ, Dobrinskikh E, Schwartz DA. Pulmonary fibrosis distal airway epithelia are dynamically and structurally dysfunctional. Nat Commun 2021; 12:4566. [PMID: 34315881 PMCID: PMC8316442 DOI: 10.1038/s41467-021-24853-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 07/06/2021] [Indexed: 01/06/2023] Open
Abstract
The airway epithelium serves as the interface between the host and external environment. In many chronic lung diseases, the airway is the site of substantial remodeling after injury. While, idiopathic pulmonary fibrosis (IPF) has traditionally been considered a disease of the alveolus and lung matrix, the dominant environmental (cigarette smoking) and genetic (gain of function MUC5B promoter variant) risk factor primarily affect the distal airway epithelium. Moreover, airway-specific pathogenic features of IPF include bronchiolization of the distal airspace with abnormal airway cell-types and honeycomb cystic terminal airway-like structures with concurrent loss of terminal bronchioles in regions of minimal fibrosis. However, the pathogenic role of the airway epithelium in IPF is unknown. Combining biophysical, genetic, and signaling analyses of primary airway epithelial cells, we demonstrate that healthy and IPF airway epithelia are biophysically distinct, identifying pathologic activation of the ERBB-YAP axis as a specific and modifiable driver of prolongation of the unjammed-to-jammed transition in IPF epithelia. Furthermore, we demonstrate that this biophysical state and signaling axis correlates with epithelial-driven activation of the underlying mesenchyme. Our data illustrate the active mechanisms regulating airway epithelial-driven fibrosis and identify targets to modulate disease progression.
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Affiliation(s)
- Ian T Stancil
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Jacob E Michalski
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Duncan Davis-Hall
- Department of Bioengineering, University of Colorado Denver | Anschutz Medical Campus, Aurora, CO, USA
| | - Hong Wei Chu
- Department of Medicine, Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
- Department of Medicine, National Jewish Health, Denver, CO, USA
| | - Jin-Ah Park
- Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Chelsea M Magin
- Department of Bioengineering, University of Colorado Denver | Anschutz Medical Campus, Aurora, CO, USA
- Department of Medicine, Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Ivana V Yang
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Bradford J Smith
- Department of Bioengineering, University of Colorado Denver | Anschutz Medical Campus, Aurora, CO, USA
- Department of Pediatrics, Division of Pediatric Pulmonary and Sleep Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Evgenia Dobrinskikh
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - David A Schwartz
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
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24
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Wang B, Chan YL, Li G, Ho KF, Anwer AG, Smith BJ, Guo H, Jalaludin B, Herbert C, Thomas PS, Liao J, Chapman DG, Foster PS, Saad S, Chen H, Oliver BG. Maternal Particulate Matter Exposure Impairs Lung Health and Is Associated with Mitochondrial Damage. Antioxidants (Basel) 2021; 10:antiox10071029. [PMID: 34202305 PMCID: PMC8300816 DOI: 10.3390/antiox10071029] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 06/24/2021] [Accepted: 06/24/2021] [Indexed: 11/16/2022] Open
Abstract
Relatively little is known about the transgenerational effects of chronic maternal exposure to low-level traffic-related air pollution (TRAP) on the offspring lung health, nor are the effects of removing such exposure before pregnancy. Female BALB/c mice were exposed to PM2.5 (PM2.5, 5 µg/day) for 6 weeks before mating and during gestation and lactation; in a subgroup, PM was removed when mating started to model mothers moving to cleaner areas during pregnancy to protect their unborn child (Pre-exposure). Lung pathology was characterised in both dams and offspring. A subcohort of female offspring was also exposed to ovalbumin to model allergic airways disease. PM2.5 and Pre-exposure dams exhibited airways hyper-responsiveness (AHR) with mucus hypersecretion, increased mitochondrial reactive oxygen species (ROS) and mitochondrial dysfunction in the lungs. Female offspring from PM2.5 and Pre-exposure dams displayed AHR with increased lung inflammation and mitochondrial ROS production, while males only displayed increased lung inflammation. After the ovalbumin challenge, AHR was increased in female offspring from PM2.5 dams compared with those from control dams. Using an in vitro model, the mitochondria-targeted antioxidant MitoQ reversed mitochondrial dysfunction by PM stimulation, suggesting that the lung pathology in offspring is driven by dysfunctional mitochondria. In conclusion, chronic exposure to low doses of PM2.5 exerted transgenerational impairment on lung health.
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Affiliation(s)
- Baoming Wang
- Faculty of Science, School of Life Sciences, University of Technology Sydney, Ultimo, NSW 2007, Australia; (B.W.); (Y.-L.C.); (G.L.); (D.G.C.); (H.C.)
- Respiratory Cellular and Molecular Biology, Woolcock Institute of Medical Research, The University of Sydney, Sydney, NSW 2037, Australia
| | - Yik-Lung Chan
- Faculty of Science, School of Life Sciences, University of Technology Sydney, Ultimo, NSW 2007, Australia; (B.W.); (Y.-L.C.); (G.L.); (D.G.C.); (H.C.)
- Respiratory Cellular and Molecular Biology, Woolcock Institute of Medical Research, The University of Sydney, Sydney, NSW 2037, Australia
| | - Gerard Li
- Faculty of Science, School of Life Sciences, University of Technology Sydney, Ultimo, NSW 2007, Australia; (B.W.); (Y.-L.C.); (G.L.); (D.G.C.); (H.C.)
| | - Kin Fai Ho
- Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China;
| | - Ayad G. Anwer
- ARC Centre of Excellence for Nanoscale Biophotonics, Faculty of Engineering, Graduate School of Biomedical Engineering, UNSW Sydney, Sydney, NSW 2052, Australia;
| | - Bradford J. Smith
- Department of Bioengineering, Department of Paediatric Pulmonary and Sleep Medicine, School of Medicine, University of Colorado, Boulder, CO 80309, USA;
| | - Hai Guo
- Air Quality Studies, Department of Civil and Environmental Engineering, Hong Kong Polytechnic University, Hong Kong, China;
| | - Bin Jalaludin
- Ingham Institute for Applied Medical Research, University of New South Wales, Sydney, NSW 2052, Australia;
- Centre for Air Pollution, Energy and Health Research (CAR), Woolcock Institute of Medical Research, The University of Sydney, Sydney, NSW 2037, Australia
| | - Cristan Herbert
- Department of Pathology, Faculty of Medicine, School of Medical Sciences, Prince of Wales’ Clinical School, University of New South Wales, Sydney, NSW 2052, Australia; (C.H.); (P.S.T.)
| | - Paul S. Thomas
- Department of Pathology, Faculty of Medicine, School of Medical Sciences, Prince of Wales’ Clinical School, University of New South Wales, Sydney, NSW 2052, Australia; (C.H.); (P.S.T.)
| | - Jiayan Liao
- Institute for Biomedical Materials and Devices, Faculty of Science, University of Technology Sydney, Ultimo, NSW 2007, Australia;
| | - David G. Chapman
- Faculty of Science, School of Life Sciences, University of Technology Sydney, Ultimo, NSW 2007, Australia; (B.W.); (Y.-L.C.); (G.L.); (D.G.C.); (H.C.)
- Respiratory Cellular and Molecular Biology, Woolcock Institute of Medical Research, The University of Sydney, Sydney, NSW 2037, Australia
| | - Paul S. Foster
- Priority Research Centre for Healthy Lungs, University of Newcastle, Callaghan, NSW 2308, Australia;
| | - Sonia Saad
- Renal Group, Kolling Institute of Medical Research, The University of Sydney, St Leonards, Sydney, NSW 2064, Australia;
| | - Hui Chen
- Faculty of Science, School of Life Sciences, University of Technology Sydney, Ultimo, NSW 2007, Australia; (B.W.); (Y.-L.C.); (G.L.); (D.G.C.); (H.C.)
| | - Brian G. Oliver
- Faculty of Science, School of Life Sciences, University of Technology Sydney, Ultimo, NSW 2007, Australia; (B.W.); (Y.-L.C.); (G.L.); (D.G.C.); (H.C.)
- Respiratory Cellular and Molecular Biology, Woolcock Institute of Medical Research, The University of Sydney, Sydney, NSW 2037, Australia
- Correspondence:
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25
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Kühn B, Vogel W, Thiel V, Merkouche S, Smith BJ. Gaussian versus Non-Gaussian Filtering of Phase-Insensitive Nonclassicality. Phys Rev Lett 2021; 126:173603. [PMID: 33988399 DOI: 10.1103/physrevlett.126.173603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 03/31/2021] [Indexed: 06/12/2023]
Abstract
Measures of quantum properties are essential to understanding the fundamental differences between quantum and classical systems as well as quantifying resources for quantum technologies. Here, two broad classes of bosonic phase-space functions, which are filtered versions of the Glauber-Sudarshan P function, are compared with regard to their ability to uncover nonclassical effects of light through their negativities. Gaussian filtering of the P function yields the family of s-parametrized quasiprobabilities, while more powerful regularized nonclassicality quasiprobabilities are obtained by non-Gaussian filtering. A method is proposed to directly sample such phase-space functions for the restricted case of phase-independent quantum states from balanced homodyne measurements. This overcomes difficulties of previous approaches that manually append uniformly distributed optical phases to the measured quadrature data. We experimentally demonstrate this technique for heralded single- and two-photon states using balanced homodyne detection with varying efficiency. The s-parametrized quasiprobabilities, which can be directly sampled, are non-negative for detection efficiencies below 0.5. By contrast, we show that significant negativities of non-Gaussian filtered quasiprobabilities uncover nonclassical effects for arbitrarily low efficiencies.
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Affiliation(s)
- B Kühn
- Arbeitsgruppe Quantenoptik, Institut für Physik, Universität Rostock, D-18051 Rostock, Germany
| | - W Vogel
- Arbeitsgruppe Quantenoptik, Institut für Physik, Universität Rostock, D-18051 Rostock, Germany
| | - V Thiel
- Clarendon Laboratory, University of Oxford, Parks Road, Oxford, OX1 3PU, United Kingdom
- Department of Physics and Oregon Center for Optical, Molecular, and Quantum Science, University of Oregon, Eugene, Oregon 97403, USA
| | - S Merkouche
- Department of Physics and Oregon Center for Optical, Molecular, and Quantum Science, University of Oregon, Eugene, Oregon 97403, USA
| | - B J Smith
- Department of Physics and Oregon Center for Optical, Molecular, and Quantum Science, University of Oregon, Eugene, Oregon 97403, USA
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26
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Knudsen L, Ochs M, Smith BJ. Editorial: Understanding Lung Acinar Micromechanics in Health and Disease: Linking Quantitative Imaging and Organ Scale Mechanics by Computational Modeling. Front Physiol 2021; 11:640398. [PMID: 33551853 PMCID: PMC7854689 DOI: 10.3389/fphys.2020.640398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 12/21/2020] [Indexed: 11/14/2022] Open
Affiliation(s)
- Lars Knudsen
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany.,Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Center for Lung Research (DZL), Hannover, Germany
| | - Matthias Ochs
- Institute of Functional Anatomy, Charité-Universitaetsmedizin Berlin, Berlin, Germany.,German Center for Lung Research (DZL), Berlin, Germany
| | - Bradford J Smith
- Department of Bioengineering, College of Engineering, Design, and Computing, University of Colorado Denver
- Anschutz Medical Campus, Aurora, CO, United States.,Section of Pulmonary and Sleep Medicine, Department of Pediatrics, School of Medicine, University of Colorado, Aurora, CO, United States
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27
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Mandell EW, Mattson C, Seedorf G, Ryan S, Gonzalez T, Wallbank A, Bye EM, Abman SH, Smith BJ. Antenatal Endotoxin Impairs Lung Mechanics and Increases Sensitivity to Ventilator-Induced Lung Injury in Newborn Rat Pups. Front Physiol 2021; 11:614283. [PMID: 33519519 PMCID: PMC7838561 DOI: 10.3389/fphys.2020.614283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 12/15/2020] [Indexed: 11/24/2022] Open
Abstract
Perinatal inflammation due to chorioamnionitis and ventilator-induced lung injury (VILI) at birth is independent risk factors for the development of bronchopulmonary dysplasia (BPD). We have previously shown that antenatal endotoxin (ETX) causes abnormal lung structure and function in 2-week-old rats, but whether ETX impairs lung mechanics at birth and increases risk for VILI is unknown. Fetal rats were exposed to 10 μg endotoxin or saline via intra-amniotic injection. At birth (D0) or 7 days (D7), rats received 90 min of lung protective ventilation [PROTECT group; tidal volume (Vt) = 6 ml/kg with positive end expiratory pressure (PEEP) = 2 cmH2O]; P20 ventilation [plateau pressure (Pplat) = 20 cmH2O, PEEP = 0]; or P24 ventilation (Pplat = 24 cmH2O, PEEP = 0, only applied to D7). Prior to prolonged ventilation at D0, endotoxin-exposed rats had decreased compliance and inspiratory capacity (IC) compared to controls. At D7, endotoxin was associated with reduced compliance. High-pressure ventilation (P20 and P24) tended to increase IC and compliance in all saline-treated groups. Ventilation at D0 with P20 increased IC and compliance when applied to saline-treated but not endotoxin-exposed pups. At D7, P24 ventilation of endotoxin-exposed pups increased elastance, bronchoalveolar lavage protein content, and IL-1b and TEN-C mRNA expression in comparison to the saline group. In summary, antenatal endotoxin exposure alters lung mechanics at birth and 1 week of life and increases susceptibility to VILI as observed in lung mechanics, alveolocapillary barrier injury, and inflammatory mRNA expression. We speculate that antenatal inflammation primes the lung for a more marked VILI response, suggesting an adverse synergistic effect of antenatal and postnatal exposures.
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Affiliation(s)
- Erica W Mandell
- Department of Pediatrics, Pediatric Heart Lung Center, School of Medicine, University of Colorado, Aurora, CO, United States.,Division of Neonatology, Department of Pediatrics, School of Medicine, University of Colorado, Aurora, CO, United States
| | - Courtney Mattson
- Department of Bioengineering, College of Engineering, Design, and Computing, University of Colorado Denver
- Anschutz Medical Campus, Aurora, CO, United States
| | - Gregory Seedorf
- Department of Pediatrics, Pediatric Heart Lung Center, School of Medicine, University of Colorado, Aurora, CO, United States.,Division of Pediatric Pulmonary and Sleep Medicine, Department of Pediatrics, School of Medicine, University of Colorado, Aurora, CO, United States
| | - Sharon Ryan
- Department of Pediatrics, Pediatric Heart Lung Center, School of Medicine, University of Colorado, Aurora, CO, United States.,Division of Neonatology, Department of Pediatrics, School of Medicine, University of Colorado, Aurora, CO, United States
| | - Tania Gonzalez
- Department of Pediatrics, Pediatric Heart Lung Center, School of Medicine, University of Colorado, Aurora, CO, United States.,Division of Neonatology, Department of Pediatrics, School of Medicine, University of Colorado, Aurora, CO, United States
| | - Alison Wallbank
- Department of Bioengineering, College of Engineering, Design, and Computing, University of Colorado Denver
- Anschutz Medical Campus, Aurora, CO, United States
| | - Elisa M Bye
- Department of Pediatrics, Pediatric Heart Lung Center, School of Medicine, University of Colorado, Aurora, CO, United States.,Division of Neonatology, Department of Pediatrics, School of Medicine, University of Colorado, Aurora, CO, United States
| | - Steven H Abman
- Department of Pediatrics, Pediatric Heart Lung Center, School of Medicine, University of Colorado, Aurora, CO, United States.,Division of Pediatric Pulmonary and Sleep Medicine, Department of Pediatrics, School of Medicine, University of Colorado, Aurora, CO, United States
| | - Bradford J Smith
- Department of Pediatrics, Pediatric Heart Lung Center, School of Medicine, University of Colorado, Aurora, CO, United States.,Department of Bioengineering, College of Engineering, Design, and Computing, University of Colorado Denver
- Anschutz Medical Campus, Aurora, CO, United States.,Division of Pediatric Pulmonary and Sleep Medicine, Department of Pediatrics, School of Medicine, University of Colorado, Aurora, CO, United States
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28
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Mori V, Smith BJ, Suki B, Bates JHT. Modeling Lung Derecruitment in VILI Due to Fluid-Occlusion: The Role of Emergent Behavior. Front Physiol 2020; 11:542744. [PMID: 33192546 PMCID: PMC7662071 DOI: 10.3389/fphys.2020.542744] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 10/08/2020] [Indexed: 12/02/2022] Open
Abstract
Ventilator-induced lung injury (VILI) is driven by the processes of volutrauma and atelectrauma, which can act synergistically to compromise the blood-gas barrier. We have postulated that this synergy arises through a rich-get-richer mechanism whereby atelectrauma causes holes to form in the blood-gas barrier while concomitant volutrauma causes susceptible holes to progressively enlarge as VILI worsens. We previously developed an analytical model based on this idea that accurately predicts the progressive increases in lung elastance seen immediately following a recruitment maneuver as VILI progresses over the course of hours. In the present study we extend this model to account for the rate of change of elastance, due to closure of lung units, in the minutes following a recruitment maneuver. We found that the distribution of unit closing velocities throughout the lung can be described by a power law with an exponent of -2 that matches previously published power laws associated with the dynamics of lung recruitment. Our model thus reveals lung collapse as an example of emergent complex behavior and links the dynamics of altered function in the injured lung to structural damage in a way that explains the mechanisms of injury progression arising from the ongoing stresses and strains applied by mechanical ventilation.
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Affiliation(s)
- Vitor Mori
- Department of Medicine, Vermont Lung Center, Larner College of Medicine, The University of Vermont, Burlington, VT, United States
- Department of Telecommunications and Control Engineering, University of São Paulo, São Paulo, Brazil
| | - Bradford J. Smith
- Department of Bioengineering, College of Engineering, Design & Computing, University of Colorado Denver, Aurora, CO, United States
| | - Bela Suki
- Department of Biomedical Engineering, Boston University, Boston, MA, United States
| | - Jason H. T. Bates
- Department of Medicine, Vermont Lung Center, Larner College of Medicine, The University of Vermont, Burlington, VT, United States
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29
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Mandell EW, Ryan S, Seedorf GJ, Gonzalez T, Smith BJ, Fleet JC, Abman SH. Maternal Vitamin D Deficiency Causes Sustained Impairment of Lung Structure and Function and Increases Susceptibility to Hyperoxia-induced Lung Injury in Infant Rats. Am J Respir Cell Mol Biol 2020; 63:79-91. [PMID: 32135073 DOI: 10.1165/rcmb.2019-0295oc] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Vitamin D deficiency (VDD) during pregnancy is associated with increased respiratory morbidities and risk for chronic lung disease after preterm birth. However, the direct effects of maternal VDD on perinatal lung structure and function and whether maternal VDD increases the susceptibility of lung injury due to hyperoxia are uncertain. In the present study, we sought to determine whether maternal VDD is sufficient to impair lung structure and function and whether VDD increases the impact of hyperoxia on the developing rat lung. Four-week-old rats were fed VDD chow and housed in a room shielded from ultraviolet A/B light to achieve 25-hydroxyvitamin D concentrations <10 ng/ml at mating and throughout lactation. Lung structure was assessed at 2 weeks for radial alveolar count, mean linear intercept, pulmonary vessel density, and lung function (lung compliance and resistance). The effects of hyperoxia for 2 weeks after birth were assessed after exposure to fraction of inspired oxygen of 0.95. At 2 weeks, VDD offspring had decreased alveolar and vascular growth and abnormal airway reactivity and lung function. Impaired lung structure and function in VDD offspring were similar to those observed in control rats exposed to postnatal hyperoxia alone. Maternal VDD causes sustained abnormalities of distal lung growth, increases in airway hyperreactivity, and abnormal lung mechanics during infancy. These changes in VDD pups were as severe as those measured after exposure to postnatal hyperoxia alone. We speculate that antenatal disruption of vitamin D signaling increases the risk for late-childhood respiratory disease.
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Affiliation(s)
| | - Sharon Ryan
- Pediatric Heart Lung Center.,Section of Neonatology, and
| | - Gregory J Seedorf
- Pediatric Heart Lung Center.,Section of Pulmonary Medicine, Department of Pediatrics, Children's Hospital Colorado and University of Colorado Anschutz Medical Center, Aurora, Colorado
| | - Tania Gonzalez
- Pediatric Heart Lung Center.,Section of Neonatology, and
| | - Bradford J Smith
- Department of Bioengineering, College of Engineering and Applied Sciences, University of Colorado Denver, Anschutz Medical Campus, Aurora, Colorado; and
| | - James C Fleet
- Department of Foods and Nutrition, and.,Interdepartmental Nutrition Program, Purdue University, West Lafayette, Indiana
| | - Steven H Abman
- Pediatric Heart Lung Center.,Section of Pulmonary Medicine, Department of Pediatrics, Children's Hospital Colorado and University of Colorado Anschutz Medical Center, Aurora, Colorado
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Sottile PD, Albers D, Smith BJ, Moss MM. Ventilator dyssynchrony - Detection, pathophysiology, and clinical relevance: A Narrative review. Ann Thorac Med 2020; 15:190-198. [PMID: 33381233 PMCID: PMC7720746 DOI: 10.4103/atm.atm_63_20] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 07/05/2020] [Indexed: 01/21/2023] Open
Abstract
Mortality associated with the acute respiratory distress syndrome remains unacceptably high due in part to ventilator-induced lung injury (VILI). Ventilator dyssynchrony is defined as the inappropriate timing and delivery of a mechanical breath in response to patient effort and may cause VILI. Such deleterious patient–ventilator interactions have recently been termed patient self-inflicted lung injury. This narrative review outlines the detection and frequency of several different types of ventilator dyssynchrony, delineates the different mechanisms by which ventilator dyssynchrony may propagate VILI, and reviews the potential clinical impact of ventilator dyssynchrony. Until recently, identifying ventilator dyssynchrony required the manual interpretation of ventilator pressure and flow waveforms. However, computerized interpretation of ventilator waive forms can detect ventilator dyssynchrony with an area under the receiver operating curve of >0.80. Using such algorithms, ventilator dyssynchrony occurs in 3%–34% of all breaths, depending on the patient population. Moreover, two types of ventilator dyssynchrony, double-triggered and flow-limited breaths, are associated with the more frequent delivery of large tidal volumes >10 mL/kg when compared with synchronous breaths (54% [95% confidence interval (CI), 47%–61%] and 11% [95% CI, 7%–15%]) compared with 0.9% (95% CI, 0.0%–1.9%), suggesting a role in propagating VILI. Finally, a recent study associated frequent dyssynchrony-defined as >10% of all breaths-with an increase in hospital mortality (67 vs. 23%, P = 0.04). However, the clinical significance of ventilator dyssynchrony remains an area of active investigation and more research is needed to guide optimal ventilator dyssynchrony management.
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Affiliation(s)
- Peter D Sottile
- Department of Medicine, Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - David Albers
- Department of Pediatrics, Division of Clinical Informatics, University of Colorado, Aurora, Colorado, USA
| | - Bradford J Smith
- Department of Bioengineering, University of Colorado Denver, Anschutz Medical Campus, Aurora, Colorado, USA
| | - Marc M Moss
- Department of Medicine, Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado School of Medicine, Aurora, Colorado, USA
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Albert K, Krischer JM, Pfaffenroth A, Wilde S, Lopez-Rodriguez E, Braun A, Smith BJ, Knudsen L. Hidden Microatelectases Increase Vulnerability to Ventilation-Induced Lung Injury. Front Physiol 2020; 11:530485. [PMID: 33071807 PMCID: PMC7530907 DOI: 10.3389/fphys.2020.530485] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 08/28/2020] [Indexed: 11/13/2022] Open
Abstract
Mechanical ventilation of lungs suffering from microatelectases may trigger the development of acute lung injury (ALI). Direct lung injury by bleomycin results in surfactant dysfunction and microatelectases at day 1 while tissue elastance and oxygenation remain normal. Computational simulations of alveolar micromechanics 1-day post-bleomycin predict persisting microatelectases throughout the respiratory cycle and increased alveolar strain during low positive end-expiratory pressure (PEEP) ventilation. As such, we hypothesize that mechanical ventilation in presence of microatelectases, which occur at low but not at higher PEEP, aggravates and unmasks ALI in the bleomycin injury model. Rats were randomized and challenged with bleomycin (B) or not (H = healthy). One day after bleomycin instillation the animals were ventilated for 3 h with PEEP 1 (PEEP1) or 5 cmH2O (PEEP5) and a tidal volume of 10 ml/kg bodyweight. Tissue elastance was repetitively measured after a recruitment maneuver to investigate the degree of distal airspace instability. The right lung was subjected to bronchoalveolar lavage (BAL), the left lung was fixed for design-based stereology at light- and electron microscopic level. Prior to mechanical ventilation, lung tissue elastance did not differ. During mechanical ventilation tissue elastance increased in bleomycin-injured lungs ventilated with PEEP = 1 cmH2O but remained stable in all other groups. Measurements at the conclusion of ventilation showed the largest time-dependent increase in tissue elastance after recruitment in B/PEEP1, indicating increased instability of distal airspaces. These lung mechanical findings correlated with BAL measurements including elevated BAL neutrophilic granulocytes as well as BAL protein and albumin in B/PEEP1. Moreover, the increased septal wall thickness and volume of peri-bronchiolar-vascular connective tissue in B/PEEP1 suggested aggravation of interstitial edema by ventilation in presence of microatelectases. At the electron microscopic level, the largest surface area of injured alveolar epithelial was observed in bleomycin-challenged lungs after PEEP = 1 cmH2O ventilation. After bleomycin treatment cellular markers of endoplasmic reticulum stress (p-Perk and p-EIF-2α) were positive within the septal wall and ventilation with PEEP = 1 cmH2O ventilation increased the surface area stained positively for p-EIF-2α. In conclusion, hidden microatelectases are linked with an increased pulmonary vulnerability for mechanical ventilation characterized by an aggravation of epithelial injury.
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Affiliation(s)
- Karolin Albert
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hanover, Germany
| | - Jeanne-Marie Krischer
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hanover, Germany
| | - Alexander Pfaffenroth
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hanover, Germany
| | - Sabrina Wilde
- Fraunhofer Institute for Toxicology and Experimental Medicine, Hanover, Germany.,Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), German Center for Lung Research, Hanover, Germany
| | - Elena Lopez-Rodriguez
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hanover, Germany.,Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), German Center for Lung Research, Hanover, Germany.,Institute for Functional Anatomy, Charité, Berlin, Germany
| | - Armin Braun
- Fraunhofer Institute for Toxicology and Experimental Medicine, Hanover, Germany.,Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), German Center for Lung Research, Hanover, Germany
| | - Bradford J Smith
- Department of Bioengineering, College of Engineering, Design and Computing, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO, United States
| | - Lars Knudsen
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hanover, Germany.,Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), German Center for Lung Research, Hanover, Germany
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Menson KE, Mank MM, Reed LF, Walton CJ, Van Der Vliet KE, Ather JL, Chapman DG, Smith BJ, Rincon M, Poynter ME. Therapeutic efficacy of IL-17A neutralization with corticosteroid treatment in a model of antigen-driven mixed-granulocytic asthma. Am J Physiol Lung Cell Mol Physiol 2020; 319:L693-L709. [PMID: 32783616 DOI: 10.1152/ajplung.00204.2020] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Many mouse models of allergic asthma exhibit eosinophil-predominant cellularity rather than the mixed-granulocytic cytology in steroid-unresponsive severe disease. Therefore, we sought to implement a novel mouse model of antigen-driven, mixed-granulocytic, severe allergic asthma to determine biomarkers of the disease process and potential therapeutic targets. C57BL/6J wild-type, interleukin-6 knockout (IL-6-/-), and IL-6 receptor knockout (IL-6R-/-), mice were injected with an emulsion of complete Freund's adjuvant and house dust mite antigen (CFA/HDM) on day 1. Dexamethasone, a lymphocyte-depleting biological, or anti-IL-17A was administered during the intranasal HDM challenge on days 19-22. On day 23, the CFA/HDM model elicited mixed bronchoalveolar lavage (BAL) cellularity (typically 80% neutrophils and 10% eosinophils), airway hyperresponsiveness (AHR) to methacholine, diffusion impairment, lung damage, body weight loss, corticosteroid resistance, and elevated levels of serum amyloid A (SAA), pro-inflammatory cytokines, and T helper type 1/ T helper type 17 (Th1/Th17) cytokines compared with eosinophilic models of HDM-driven allergic airway disease. BAL cells in IL-6- or IL-6R-deficient mice were predominantly eosinophilic and associated with elevated T helper type 2 (Th2) and reduced Th1/Th17 cytokine production, along with an absence of SAA. Nevertheless, AHR remained in IL-6-deficient mice even when dexamethasone was administered. However, combined administration of anti-IL-17A and systemic corticosteroid significantly attenuated both overall and neutrophilic airway inflammation and also reduced AHR and body weight loss. Inhibition of IL-17A combined with systemic corticosteroid treatment during antigen-driven exacerbations may provide a novel therapeutic approach to prevent the pathological pulmonary and constitutional changes that greatly impact patients with the mixed-granulocytic endotype of severe asthma.
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Affiliation(s)
- Katherine E Menson
- Division of Pulmonary Disease & Critical Care, Department of Medicine, The Vermont Lung Center, University of Vermont, Burlington, Vermont
| | - Madeleine M Mank
- Division of Pulmonary Disease & Critical Care, Department of Medicine, The Vermont Lung Center, University of Vermont, Burlington, Vermont
| | - Leah F Reed
- Division of Pulmonary Disease & Critical Care, Department of Medicine, The Vermont Lung Center, University of Vermont, Burlington, Vermont
| | - Camille J Walton
- Division of Pulmonary Disease & Critical Care, Department of Medicine, The Vermont Lung Center, University of Vermont, Burlington, Vermont
| | - Katherine E Van Der Vliet
- Division of Pulmonary Disease & Critical Care, Department of Medicine, The Vermont Lung Center, University of Vermont, Burlington, Vermont
| | - Jennifer L Ather
- Division of Pulmonary Disease & Critical Care, Department of Medicine, The Vermont Lung Center, University of Vermont, Burlington, Vermont
| | - David G Chapman
- Translational Airways Group, School of Life Sciences, University of Technology Sydney, Sydney, New South Wales, Australia
| | - Bradford J Smith
- Department of Bioengineering, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado
| | - Mercedes Rincon
- Department of Immunology & Microbiology, University of Colorado Anschutz School of Medicine, Aurora, Colorado
| | - Matthew E Poynter
- Division of Pulmonary Disease & Critical Care, Department of Medicine, The Vermont Lung Center, University of Vermont, Burlington, Vermont
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Kheyfets VO, Lammers SR, Wagner J, Bartels K, Piccoli J, Smith BJ. PEEP/ FIO2 ARDSNet Scale Grouping of a Single Ventilator for Two Patients: Modeling Tidal Volume Response. Respir Care 2020; 65:1094-1103. [PMID: 32712582 DOI: 10.4187/respcare.07931] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
BACKGROUND The COVID-19 pandemic is creating ventilator shortages in many countries that is sparking a conversation about placing multiple patients on a single ventilator. However, on March 26, 2020, six leading medical organizations released a joint statement warning clinicians that attempting this technique could lead to poor outcomes and high mortality. Nevertheless, hospitals around the United States and abroad are considering this technique out of desperation (eg, New York), but there is little data to guide their approach. The overall objective of this study is to utilize a computational model of mechanically ventilated lungs to assess how patient-specific lung mechanics and ventilator settings impact lung tidal volume (VT). METHODS We developed a lumped-parameter computational model of multiple patients connected to a shared ventilator and validated it against a similar experimental study. We used this model to evaluate how patient-specific lung compliance and resistance would impact VT under 4 ventilator settings of pressure control level, PEEP, breathing frequency, and inspiratory:expiratory ratio. RESULTS Our computational model predicts VT within 10% of experimental measurements. Using this model to perform a parametric study, we provide proof-of-concept for an algorithm to better match patients in different hypothetical scenarios of a single ventilator shared by > 1 patient. CONCLUSIONS Assigning patients to preset ventilators based on their required level of support on the lower PEEP/higher [Formula: see text] scale of the National Institute of Health's National Heart, Lung, and Blood Institute ARDS Clinical Network (ARDSNet), secondary to lung mechanics, could be used to overcome some of the legitimate concerns of placing multiple patients on a single ventilator. We emphasize that our results are currently based on a computational model that has not been validated against any preclinical or clinical data. Therefore, clinicians considering this approach should not look to our study as an exact estimate of predicted patient VT values.
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Affiliation(s)
- Vitaly O Kheyfets
- Department of Bioengineering, University of Colorado Denver, Anschutz Medical Campus, Aurora, Colorado.
| | - Steven R Lammers
- Department of Bioengineering, University of Colorado Denver, Anschutz Medical Campus, Aurora, Colorado
| | - Jennifer Wagner
- Department of Bioengineering, University of Colorado Denver, Anschutz Medical Campus, Aurora, Colorado
| | - Karsten Bartels
- Department of Anesthesiology, Psychiatry, Medicine, and Surgery, University of Colorado School of Medicine, Aurora, Colorado
| | - Jerome Piccoli
- University of Colorado School of Medicine, Aurora, Colorado
| | - Bradford J Smith
- Department of Bioengineering, University of Colorado Denver, Anschutz Medical Campus, Aurora, Colorado
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Smith BJ, Roy GS, Cleveland A, Mattson C, Okamura K, Charlebois CM, Hamlington KL, Novotny MV, Knudsen L, Ochs M, Hite RD, Bates JHT. Three Alveolar Phenotypes Govern Lung Function in Murine Ventilator-Induced Lung Injury. Front Physiol 2020; 11:660. [PMID: 32695013 PMCID: PMC7338482 DOI: 10.3389/fphys.2020.00660] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 05/25/2020] [Indexed: 01/03/2023] Open
Abstract
Mechanical ventilation is an essential lifesaving therapy in acute respiratory distress syndrome (ARDS) that may cause ventilator-induced lung injury (VILI) through a positive feedback between altered alveolar mechanics, edema, surfactant inactivation, and injury. Although the biophysical forces that cause VILI are well documented, a knowledge gap remains in the quantitative link between altered parenchymal structure (namely alveolar derecruitment and flooding), pulmonary function, and VILI. This information is essential to developing diagnostic criteria and ventilation strategies to reduce VILI and improve ARDS survival. To address this unmet need, we mechanically ventilated mice to cause VILI. Lung structure was measured at three air inflation pressures using design-based stereology, and the mechanical function of the pulmonary system was measured with the forced oscillation technique. Assessment of the pulmonary surfactant included total surfactant, distribution of phospholipid aggregates, and surface tension lowering activity. VILI-induced changes in the surfactant included reduced surface tension lowering activity in the typically functional fraction of large phospholipid aggregates and a significant increase in the pool of surface-inactive small phospholipid aggregates. The dominant alterations in lung structure at low airway pressures were alveolar collapse and flooding. At higher airway pressures, alveolar collapse was mitigated and the flooded alveoli remained filled with proteinaceous edema. The loss of ventilated alveoli resulted in decreased alveolar gas volume and gas-exchange surface area. These data characterize three alveolar phenotypes in murine VILI: flooded and non-recruitable alveoli, unstable alveoli that derecruit at airway pressures below 5 cmH2O, and alveoli with relatively normal structure and function. The fraction of alveoli with each phenotype is reflected in the proportional changes in pulmonary system elastance at positive end expiratory pressures of 0, 3, and 6 cmH2O.
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Affiliation(s)
- Bradford J Smith
- Department of Bioengineering, College of Engineering, Design & Computing, University of Colorado Denver | Anschutz Medical Campus, Aurora, CO, United States
- Department of Pediatric Pulmonary and Sleep Medicine, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Gregory S Roy
- Vermont Lung Center, Larner College of Medicine, The University of Vermont, Burlington, VT, United States
| | - Alyx Cleveland
- Vermont Lung Center, Larner College of Medicine, The University of Vermont, Burlington, VT, United States
| | - Courtney Mattson
- Department of Bioengineering, College of Engineering, Design & Computing, University of Colorado Denver | Anschutz Medical Campus, Aurora, CO, United States
| | - Kayo Okamura
- Department of Bioengineering, College of Engineering, Design & Computing, University of Colorado Denver | Anschutz Medical Campus, Aurora, CO, United States
| | - Chantel M Charlebois
- Vermont Lung Center, Larner College of Medicine, The University of Vermont, Burlington, VT, United States
| | - Katharine L Hamlington
- Department of Pediatric Pulmonary and Sleep Medicine, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Michael V Novotny
- Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
| | - Lars Knudsen
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hanover, Germany
- Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Center for Lung Research, Hanover, Germany
| | - Matthias Ochs
- Institute of Functional Anatomy, Charité Medical University of Berlin, Berlin, Germany
| | - R Duncan Hite
- Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Internal Medicine, College of Medicine, University of Cincinnati, Cincinnati, OH, United States
| | - Jason H T Bates
- Vermont Lung Center, Larner College of Medicine, The University of Vermont, Burlington, VT, United States
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Hume PS, Gibbings SL, Jakubzick CV, Tuder RM, Curran-Everett D, Henson PM, Smith BJ, Janssen WJ. Localization of Macrophages in the Human Lung via Design-based Stereology. Am J Respir Crit Care Med 2020; 201:1209-1217. [PMID: 32197050 PMCID: PMC7233346 DOI: 10.1164/rccm.201911-2105oc] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Rationale: Interstitial macrophages (IMs) and airspace macrophages (AMs) play critical roles in lung homeostasis and host defense, and are central to the pathogenesis of a number of lung diseases. However, the absolute numbers of macrophages and the precise anatomic locations they occupy in the healthy human lung have not been quantified.Objectives: To determine the precise number and anatomic location of human pulmonary macrophages in nondiseased lungs and to quantify how this is altered in chronic cigarette smokers.Methods: Whole right upper lobes from 12 human donors without pulmonary disease (6 smokers and 6 nonsmokers) were evaluated using design-based stereology. CD206 (cluster of differentiation 206)-positive/CD43+ AMs and CD206+/CD43- IMs were counted in five distinct anatomical locations using the optical disector probe.Measurements and Main Results: An average of 2.1 × 109 IMs and 1.4 × 109 AMs were estimated per right upper lobe. Of the AMs, 95% were contained in diffusing airspaces and 5% in airways. Of the IMs, 78% were located within the alveolar septa, 14% around small vessels, and 7% around the airways. The local density of IMs was greater in the alveolar septa than in the connective tissue surrounding the airways or vessels. The total number and density of IMs was 36% to 56% greater in the lungs of cigarette smokers versus nonsmokers.Conclusions: The precise locations occupied by pulmonary macrophages were defined in nondiseased human lungs from smokers and nonsmokers. IM density was greatest in the alveolar septa. Lungs from chronic smokers had increased IM numbers and overall density, supporting a role for IMs in smoking-related disease.
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Affiliation(s)
- Patrick S. Hume
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, and,Division of Pulmonary Sciences and Critical Care Medicine
| | - Sophie L. Gibbings
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, and
| | - Claudia V. Jakubzick
- Department of Microbiology and Immunology, Dartmouth College, Hanover, New Hampshire
| | - Rubin M. Tuder
- Division of Pulmonary Sciences and Critical Care Medicine
| | - Douglas Curran-Everett
- Division of Biostatistics and Bioinformatics, National Jewish Health, Denver, Colorado,Department of Biostatistics and Informatics, Colorado School of Public Health, and
| | - Peter M. Henson
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, and,Division of Pulmonary Sciences and Critical Care Medicine
| | - Bradford J. Smith
- Department of Biomedical Engineering, University of Colorado, Anschutz Medical Campus, Aurora, Colorado; and
| | - William J. Janssen
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, and,Division of Pulmonary Sciences and Critical Care Medicine
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Bou Jawde S, Walkey AJ, Majumdar A, O'Connor GT, Smith BJ, Bates JHT, Lutchen KR, Suki B. Tracking respiratory mechanics around natural breathing rates via variable ventilation. Sci Rep 2020; 10:6722. [PMID: 32317734 PMCID: PMC7174375 DOI: 10.1038/s41598-020-63663-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 03/26/2020] [Indexed: 11/08/2022] Open
Abstract
Measuring respiratory resistance and elastance as a function of time, tidal volume, respiratory rate, and positive end-expiratory pressure can guide mechanical ventilation. However, current measurement techniques are limited since they are assessed intermittently at non-physiological frequencies or involve specialized equipment. To this end, we introduce ZVV, a practical approach to continuously track resistance and elastance during Variable Ventilation (VV), in which frequency and tidal volume vary from breath-to-breath. ZVV segments airway pressure and flow recordings into individual breaths, calculates resistance and elastance for each breath, bins them according to frequency or tidal volume and plots the results against bin means. ZVV's feasibility was assessed clinically in five human patients with acute lung injury, experimentally in five mice ventilated before and after lavage injury, and computationally using a viscoelastic respiratory model. ZVV provided continuous measurements in both settings, while the computational study revealed <2% estimation errors. Our findings support ZVV as a feasible technique to assess respiratory mechanics under physiological conditions. Additionally, in humans, ZVV detected a decrease in resistance and elastance with time by 12.8% and 6.2%, respectively, suggesting that VV can improve lung recruitment in some patients and can therefore potentially serve both as a dual diagnostic and therapeutic tool.
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Affiliation(s)
- Samer Bou Jawde
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Allan J Walkey
- Department of Medicine, Pulmonary, Allergy, Sleep, & Critical Care Medicine, Boston University, Boston, MA, USA
| | - Arnab Majumdar
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - George T O'Connor
- Department of Medicine, Pulmonary, Allergy, Sleep, & Critical Care Medicine, Boston University, Boston, MA, USA
| | - Bradford J Smith
- Department of Bioengineering, University of Colorado Denver | Anschutz Medical Campus, Aurora, CO, USA
| | - Jason H T Bates
- Pulmonary/Critical Care Division, University of Vermont, Burlington, VT, USA
| | - Kenneth R Lutchen
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Béla Suki
- Department of Biomedical Engineering, Boston University, Boston, MA, USA.
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Selby TH, Hart KM, Smith BJ, Pollock CG, Hillis-Starr Z, Oli MK. Juvenile hawksbill residency and habitat use within a Caribbean marine protected area. ENDANGER SPECIES RES 2019. [DOI: 10.3354/esr00975] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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38
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Rühl N, Lopez-Rodriguez E, Albert K, Smith BJ, Weaver TE, Ochs M, Knudsen L. Surfactant Protein B Deficiency Induced High Surface Tension: Relationship between Alveolar Micromechanics, Alveolar Fluid Properties and Alveolar Epithelial Cell Injury. Int J Mol Sci 2019; 20:ijms20174243. [PMID: 31480246 PMCID: PMC6747270 DOI: 10.3390/ijms20174243] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 08/24/2019] [Accepted: 08/26/2019] [Indexed: 11/16/2022] Open
Abstract
High surface tension at the alveolar air-liquid interface is a typical feature of acute and chronic lung injury. However, the manner in which high surface tension contributes to lung injury is not well understood. This study investigated the relationship between abnormal alveolar micromechanics, alveolar epithelial injury, intra-alveolar fluid properties and remodeling in the conditional surfactant protein B (SP-B) knockout mouse model. Measurements of pulmonary mechanics, broncho-alveolar lavage fluid (BAL), and design-based stereology were performed as a function of time of SP-B deficiency. After one day of SP-B deficiency the volume of alveolar fluid V(alvfluid,par) as well as BAL protein and albumin levels were normal while the surface area of injured alveolar epithelium S(AEinjure,sep) was significantly increased. Alveoli and alveolar surface area could be recruited by increasing the air inflation pressure. Quasi-static pressure-volume loops were characterized by an increased hysteresis while the inspiratory capacity was reduced. After 3 days, an increase in V(alvfluid,par) as well as BAL protein and albumin levels were linked with a failure of both alveolar recruitment and airway pressure-dependent redistribution of alveolar fluid. Over time, V(alvfluid,par) increased exponentially with S(AEinjure,sep). In conclusion, high surface tension induces alveolar epithelial injury prior to edema formation. After passing a threshold, epithelial injury results in vascular leakage and exponential accumulation of alveolar fluid critically hampering alveolar recruitability.
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Affiliation(s)
- Nina Rühl
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover 30625, Germany
| | - Elena Lopez-Rodriguez
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover 30625, Germany
- Biomedical Research in Endstage and Obstructive Lung Diseases (BREATH), Member of the German Center for Lung Research (DLZ), Hannover 30625, Germany
- REBIRTH, Cluster of Excellence, Hannover 30625, Germany
- Institute of Vegetative Anatomy, Charite, Berlin 10117, Germany
| | - Karolin Albert
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover 30625, Germany
| | - Bradford J Smith
- Department of Bioengineering, University of Colorado Denver, Denver, CO 80045, USA
| | - Timothy E Weaver
- Division of Pulmonary Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45221, USA
| | - Matthias Ochs
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover 30625, Germany
- Biomedical Research in Endstage and Obstructive Lung Diseases (BREATH), Member of the German Center for Lung Research (DLZ), Hannover 30625, Germany
- REBIRTH, Cluster of Excellence, Hannover 30625, Germany
- Institute of Vegetative Anatomy, Charite, Berlin 10117, Germany
| | - Lars Knudsen
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover 30625, Germany.
- Biomedical Research in Endstage and Obstructive Lung Diseases (BREATH), Member of the German Center for Lung Research (DLZ), Hannover 30625, Germany.
- REBIRTH, Cluster of Excellence, Hannover 30625, Germany.
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Mellenthin MM, Seong SA, Roy GS, Bartolák-Suki E, Hamlington KL, Bates JHT, Smith BJ. Using injury cost functions from a predictive single-compartment model to assess the severity of mechanical ventilator-induced lung injuries. J Appl Physiol (1985) 2019; 127:58-70. [PMID: 31046518 DOI: 10.1152/japplphysiol.00770.2018] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Identifying safe ventilation patterns for patients with acute respiratory distress syndrome remains challenging because of the delicate balance between gas exchange and selection of ventilator settings to prevent further ventilator-induced lung injury (VILI). Accordingly, this work seeks to link ventilator settings to graded levels of VILI to identify injury cost functions that predict injury by using a computational model to process pressures and flows measured at the airway opening. Pressure-volume loops were acquired over the course of ~2 h of mechanical ventilation in four different groups of BALB/c mice. A cohort of these animals were subjected to an injurious bronchoalveolar lavage before ventilation. The data were analyzed with a single-compartment model that predicts recruitment/derecruitment and tissue distension at each time step in measured pressure-volume loops. We compared several injury cost functions to markers of VILI-induced blood-gas barrier disruption. Of the cost functions considered, we conclude that mechanical power dissipation and strain heterogeneity are the best at distinguishing between graded levels of injury and are good candidates for forecasting the development of VILI. NEW & NOTEWORTHY This work uses a predictive single-compartment model and injury cost functions to assess graded levels of mechanical ventilator-induced lung injury. The most promising measures include strain heterogeneity and mechanical power dissipation.
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Affiliation(s)
| | - Siyeon A Seong
- College of Medicine, University of Vermont , Burlington, Vermont
| | - Gregory S Roy
- College of Medicine, University of Vermont , Burlington, Vermont
| | | | - Katharine L Hamlington
- College of Medicine, University of Vermont , Burlington, Vermont.,University of Colorado at Children's Hospital Colorado , Aurora, Colorado
| | - Jason H T Bates
- College of Medicine, University of Vermont , Burlington, Vermont
| | - Bradford J Smith
- Department of Bioengineering, University of Colorado Denver , Aurora, Colorado.,College of Medicine, University of Vermont , Burlington, Vermont
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40
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Knudsen L, Lopez-Rodriguez E, Berndt L, Steffen L, Ruppert C, Bates JHT, Ochs M, Smith BJ. Alveolar Micromechanics in Bleomycin-induced Lung Injury. Am J Respir Cell Mol Biol 2018; 59:757-769. [PMID: 30095988 PMCID: PMC6293074 DOI: 10.1165/rcmb.2018-0044oc] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Accepted: 06/29/2018] [Indexed: 12/22/2022] Open
Abstract
Lung injury results in intratidal alveolar recruitment and derecruitment and alveolar collapse, creating stress concentrators that increase strain and aggravate injury. In this work, we sought to describe alveolar micromechanics during mechanical ventilation in bleomycin-induced lung injury and surfactant replacement therapy. Structure and function were assessed in rats 1 day and 3 days after intratracheal bleomycin instillation and after surfactant replacement therapy. Pulmonary system mechanics were measured during ventilation with positive end-expiratory pressures (PEEPs) between 1 and 10 cm H2O, followed by perfusion fixation at end-expiratory pressure at airway opening (Pao) values of 1, 5, 10, and 20 cm H2O for quantitative analyses of lung structure. Lung structure and function were used to parameterize a physiologically based, multicompartment computational model of alveolar micromechanics. In healthy controls, the numbers of open alveoli remained stable in a range of Pao = 1-20 cm H2O, whereas bleomycin-challenged lungs demonstrated progressive alveolar derecruitment with Pao < 10 cm H2O. At Day 3, ∼40% of the alveoli remained closed at high Pao, and alveolar size heterogeneity increased. Simulations of injured lungs predicted that alveolar recruitment pressures were much greater than the derecruitment pressures, so that minimal intratidal recruitment and derecruitment occurred during mechanical ventilation with a tidal volume of 10 ml/kg body weight over a range of PEEPs. However, the simulations also predicted a dramatic increase in alveolar strain with injury that we attribute to alveolar interdependence. These findings suggest that in progressive lung injury, alveolar collapse with increased distension of patent (open) alveoli dominates alveolar micromechanics. PEEP and surfactant substitution reduce alveolar collapse and dynamic strain but increase static strain.
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Affiliation(s)
- Lars Knudsen
- Institute of Functional and Applied Anatomy, and
- Biomedical Research in Endstage and Obstructive Lung Disease Hannover, Member of the German Center for Lung Research (DZL) Hannover Medical School, Hannover, Germany
- REBIRTH, Cluster of Excellence, Hannover, Germany
| | - Elena Lopez-Rodriguez
- Institute of Functional and Applied Anatomy, and
- Biomedical Research in Endstage and Obstructive Lung Disease Hannover, Member of the German Center for Lung Research (DZL) Hannover Medical School, Hannover, Germany
- REBIRTH, Cluster of Excellence, Hannover, Germany
| | | | | | - Clemens Ruppert
- Department of Internal Medicine, and
- Universities of Giessen and Marburg Lung Center, Member of the German Center for Lung Research (DZL), Justus Liebig University Giessen, Giessen, Germany
| | | | - Matthias Ochs
- Institute of Functional and Applied Anatomy, and
- Biomedical Research in Endstage and Obstructive Lung Disease Hannover, Member of the German Center for Lung Research (DZL) Hannover Medical School, Hannover, Germany
- REBIRTH, Cluster of Excellence, Hannover, Germany
| | - Bradford J. Smith
- Department of Bioengineering, University of Colorado Denver, Denver, Colorado
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Mori V, Smith BJ, Suki B, Bates JHT. Linking Physiological Biomarkers of Ventilator-Induced Lung Injury to a Rich-Get-Richer Mechanism of Injury Progression. Ann Biomed Eng 2018; 47:638-645. [PMID: 30421177 DOI: 10.1007/s10439-018-02165-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 11/01/2018] [Indexed: 01/11/2023]
Abstract
Mechanical ventilation is a crucial tool in the management of acute respiratory distress syndrome, yet it may itself also further damage the lung in a phenomenon known as ventilator-induced lung injury (VILI). We have previously shown in mice that volutrauma and atelectrauma act synergistically to cause VILI. We have also postulated that this synergy arises because of a rich-get-richer mechanism in which repetitive lung recruitment generates initial small holes in the blood-gas barrier which are then expanded by over-distension in a manner that favors large holes over small ones. In order to understand the causal link between this process and the derangements in lung mechanics associated with VILI, we developed a mathematical model that incorporates both atelectrauma and volutrauma to predict how the propensity of the lung to derecruit depends on the accumulation of plasma-derived fluid and proteins in the airspaces. We found that the model accurately predicts derecruitment in mice with experimentally induced VILI.
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Affiliation(s)
- Vitor Mori
- Department of Medicine, Vermont Lung Center, University of Vermont College of Medicine, 149 Beaumont Ave, HSRF 228, Burlington, VT, 05405, USA.,Department of Telecommunications and Control Engineering, University of Sao Paulo, Sao Paulo, Brazil
| | - Bradford J Smith
- Department of Bioengineering, University of Colorado Denver, Aurora, CO, 80045, USA
| | - Bela Suki
- Department of Biomedical Engineering, Boston University, Boston, MA, 02215, USA
| | - Jason H T Bates
- Department of Medicine, Vermont Lung Center, University of Vermont College of Medicine, 149 Beaumont Ave, HSRF 228, Burlington, VT, 05405, USA.
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Abstract
Mechanical ventilation applies physical stresses to the tissues of the lung and thus may give rise to ventilator-induced lung injury (VILI), particular in patients with acute respiratory distress syndrome (ARDS). The most dire consequences of VILI result from injury to the blood-gas barrier. This allows plasma-derived fluid and proteins to leak into the airspaces where they flood some alveolar regions, while interfering with the functioning of pulmonary surfactant in those regions that remain open. These effects are reflected in commensurately increased values of dynamic lung elastance (EL ), a quantity that in principle is readily measured at the bedside. Recent mathematical/computational modeling studies have shown that the way in which EL varies as a function of both time and positive end-expiratory pressure (PEEP) reflects the nature and degree of lung injury, and can even be used to infer the separate contributions of volutrauma and atelectrauma to VILI. Interrogating such models for minimally injurious regimens of mechanical ventilation that apply to a particular lung may thus lead to personalized approaches to the ventilatory management of ARDS.
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Affiliation(s)
- Jason H. T. Bates
- Department of Medicine, University of Vermont Larner College of Medicine, Burlington, VT, USA
| | - Bradford J. Smith
- Department of Bioengineering, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO, USA
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Smith BJ, Leyva MJ, Stephens LD, Aston CE, Hermann J, Payton M, Baker MZ. Relationship of American Indian blood quantum with osteoporosis risk: a cross-sectional study of American Indian women in Oklahoma. Osteoporos Int 2018; 29:2251-2260. [PMID: 29943190 PMCID: PMC9134873 DOI: 10.1007/s00198-018-4594-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 05/29/2018] [Indexed: 11/27/2022]
Abstract
UNLABELLED Information regarding the prevalence and risk of osteoporosis among American Indian (AI) women is limited. This study showed that with increasing AI blood quantum, the prevalence of osteoporosis at the hip based on BMD T-scores decreased and this appeared to be independent of other risk factors. INTRODUCTION This study was designed to investigate the effects of AI blood quantum (BQ) on osteoporosis prevalence and risk in a cohort of AI women in Oklahoma. METHODS Women (n = 301), aged 50 years and older, were recruited to participate in the Oklahoma American Indian Women's Osteoporosis Study. Baseline bone density, fracture history, bone biochemical markers, and potential risk factors were assessed. Participants were stratified by AI BQ into BQ1 ≤ 25%, BQ2 = 25-49%, BQ3 = 50-74%, and BQ4 = 75-100%. The effects of BQ on the prevalence and risk of osteoporosis were evaluated. RESULTS Based on T-scores, one in approximately eight women in the study was osteoporotic at one or more sites. The prevalence of osteoporosis decreased (p < 0.05) with increasing BQ, especially at the hip, trochanteric, and intertrochanter regions. No differences in bone-specific alkaline phosphatase and C-telopeptide were observed across BQ that could account for the differences in bone density. 25-OH vitamin D decreased with increasing BQ, but mean for each BQ1-4 was > 40 ng/mL. Fracture history did not differ across BQ, and though 52% of the population consumed less than the RDA for calcium, no effect of BQ was observed. CONCLUSIONS In this cohort of women who identified as AI, greater Indian BQ was associated with a decrease in the prevalence of osteoporosis.
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Affiliation(s)
- B J Smith
- Department of Nutritional Sciences, Oklahoma State University, 420 Human Sciences, Stillwater, OK, 74078, USA.
| | - M J Leyva
- Health Promotion Sciences, College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - L D Stephens
- Health Promotion Sciences, College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - C E Aston
- Department of Pediatrics CMRI Metabolic Research Program, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - J Hermann
- Department of Nutritional Sciences, Oklahoma State University, 420 Human Sciences, Stillwater, OK, 74078, USA
| | - M Payton
- Department of Statistics, College of Arts and Sciences, Oklahoma State University, Stillwater, OK, USA
| | - M Z Baker
- Section of Endocrinology and Diabetes, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
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Abstract
OBJECTIVE While many studies rely on flow and pressure measurements in small animal models of respiratory disease, such measurements can however be inaccurate and difficult to obtain. Thus, the goal of this study was to design and implement an easy-to-manufacture and accurate sensor capable of monitoring flow. APPROACH We designed and 3D printed a flowmeter and utilized parametric (resistance and inertance) and nonparametric (polynomial and Volterra series) system identification to characterize the device. The sensor was tested in a closed system for apparent flow using the common mode rejection ratio (CMRR). The sensor properly measured tidal volumes and respiratory rates in spontaneously breathing mice. The device was used to evaluate a ventilator's ability to deliver a prescribed volume before and after lung injury. MAIN RESULTS The parametric and polynomial models provided a reasonable prediction of the independently measured flow (Adjusted coefficient of determination [Formula: see text] = 0.9591 and 0.9147 respectively), but the Volterra series of the 1st, 2nd, and 3rd order with a memory of six time points provided better fits ([Formula: see text] = 0.9775, 0.9787, and 0.9954, respectively). At and below the mouse breathing frequency (1-5 Hz), CMRR was higher than 40 dB. Following lung injury, the sensor revealed a significant drop in delivered tidal volume. SIGNIFICANCE We demonstrate that the application of nonparametric nonlinear Volterra series modeling in combination with 3D printing technology allows the inexpensive and rapid fabrication of an accurate flow sensor for continuously measuring small flows in various physiological conditions.
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Schwarzman J, Bauman A, Gabbe B, Rissel C, Shilton T, Smith BJ. Organizational determinants of evaluation practice in Australian prevention agencies. Health Educ Res 2018; 33:243-255. [PMID: 29746649 DOI: 10.1093/her/cyy015] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 04/20/2018] [Indexed: 06/08/2023]
Abstract
Program evaluation is essential to inform decision making, contribute to the evidence base for strategies, and facilitate learning in health promotion and disease prevention organizations. Theoretical frameworks of organizational learning, and studies of evaluation capacity building describe the organization as central to evaluation capacity. Australian prevention organizations recognize limitations to current evaluation effectiveness and are seeking guidance to build evaluation capacity. This qualitative study identifies organizational facilitators and barriers to evaluation practice, and explores their interactions in Australian prevention organizations. We conducted semi-structured interviews with 40 experienced practitioners from government and non-government organizations. Using thematic analysis, we identified seven key themes that influence evaluation practice: leadership, organizational culture, organizational systems and structures, partnerships, resources, workforce development and training and recruitment and skills mix. We found organizational determinants of evaluation to have multi-level interactions. Leadership and organizational culture influenced organizational systems, resource allocation and support of staff. Partnerships were important to overcome resource deficits, and systems were critical to embed evaluation within the organization. Organizational factors also influenced the opportunities for staff to develop skills and confidence. We argue that investment to improve these factors would allow organizations to address evaluation capacity at multiple levels, and ultimately facilitate effective evaluation practice.
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Affiliation(s)
- J Schwarzman
- School of Public Health and Preventive Medicine, Monash University, 553 St Kilda Road, Melbourne, VIC 3004, Australia
| | - A Bauman
- Prevention Research Collaboration, School of Public Health, L6 The Hub, Charles Perkins Centre, University of Sydney, Sydney, NSW 2006, Australia
| | - B Gabbe
- School of Public Health and Preventive Medicine, Monash University, 553 St Kilda Road, Melbourne, VIC 3004, Australia
| | - C Rissel
- NSW Office of Preventive Health, Don Everett Building, Level 1, Liverpool Hospital, Liverpool, NSW 2170, Australia
| | - T Shilton
- National Heart Foundation Western Australia, 334 Rokeby Road, Subiaco, WA 6008, Australia
| | - B J Smith
- School of Public Health and Preventive Medicine, Monash University, 553 St Kilda Road, Melbourne, VIC 3004, Australia
- Prevention Research Collaboration, School of Public Health, L6 The Hub, Charles Perkins Centre, University of Sydney, Sydney, NSW 2006, Australia
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Hamlington KL, Smith BJ, Dunn CM, Charlebois CM, Roy GS, Bates JHT. Linking lung function to structural damage of alveolar epithelium in ventilator-induced lung injury. Respir Physiol Neurobiol 2018; 255:22-29. [PMID: 29742448 DOI: 10.1016/j.resp.2018.05.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 05/02/2018] [Accepted: 05/05/2018] [Indexed: 12/21/2022]
Abstract
Understanding how the mechanisms of ventilator-induced lung injury (VILI), namely atelectrauma and volutrauma, contribute to the failure of the blood-gas barrier and subsequent intrusion of edematous fluid into the airspace is essential for the design of mechanical ventilation strategies that minimize VILI. We ventilated mice with different combinations of tidal volume and positive end-expiratory pressure (PEEP) and linked degradation in lung function measurements to injury of the alveolar epithelium observed via scanning electron microscopy. Ventilating with both high inspiratory plateau pressure and zero PEEP was necessary to cause derangements in lung function as well as visually apparent physical damage to the alveolar epithelium of initially healthy mice. In particular, the epithelial injury was tightly associated with indicators of alveolar collapse. These results support the hypothesis that mechanical damage to the epithelium during VILI is at least partially attributed to atelectrauma-induced damage of alveolar type I epithelial cells.
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Affiliation(s)
- Katharine L Hamlington
- Department of Medicine, University of Vermont Larner College of Medicine, Burlington, VT 05405, USA.
| | - Bradford J Smith
- Department of Medicine, University of Vermont Larner College of Medicine, Burlington, VT 05405, USA.
| | - Celia M Dunn
- Department of Medicine, University of Vermont Larner College of Medicine, Burlington, VT 05405, USA
| | - Chantel M Charlebois
- Department of Medicine, University of Vermont Larner College of Medicine, Burlington, VT 05405, USA
| | - Gregory S Roy
- Department of Medicine, University of Vermont Larner College of Medicine, Burlington, VT 05405, USA
| | - Jason H T Bates
- Department of Medicine, University of Vermont Larner College of Medicine, Burlington, VT 05405, USA.
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47
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Hamlington KL, Bates JHT, Roy GS, Julianelle AJ, Charlebois C, Suki B, Smith BJ. Alveolar leak develops by a rich-get-richer process in ventilator-induced lung injury. PLoS One 2018; 13:e0193934. [PMID: 29590136 PMCID: PMC5874026 DOI: 10.1371/journal.pone.0193934] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 01/31/2018] [Indexed: 02/07/2023] Open
Abstract
Acute respiratory distress syndrome (ARDS) is a life-threatening condition for which there are currently no medical therapies other than supportive care involving the application of mechanical ventilation. However, mechanical ventilation itself can worsen ARDS by damaging the alveolocapillary barrier in the lungs. This allows plasma-derived fluid and proteins to leak into the airspaces of the lung where they interfere with the functioning of pulmonary surfactant, which increases the stresses of mechanical ventilation and worsens lung injury. Once such ventilator-induced lung injury (VILI) is underway, managing ARDS and saving the patient becomes increasingly problematic. Maintaining an intact alveolar barrier thus represents a crucial management goal, but the biophysical processes that perforate this barrier remain incompletely understood. To study the dynamics of barrier perforation, we subjected initially normal mice to an injurious ventilation regimen that imposed both volutrauma (overdistension injury) and atelectrauma (injury from repetitive reopening of closed airspaces) on the lung, and observed the rate at which macromolecules of various sizes leaked into the airspaces as a function of the degree of overall injury. Computational modeling applied to our findings suggests that perforations in the alveolocapillary barrier appear and progress according to a rich-get-richer mechanism in which the likelihood of a perforation getting larger increases with the size of the perforation. We suggest that atelectrauma causes the perforations after which volutrauma expands them. This mechanism explains why atelectrauma appears to be essential to the initiation of VILI in a normal lung, and why atelectrauma and volutrauma then act synergistically once VILI is underway.
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Affiliation(s)
- Katharine L. Hamlington
- Vermont Lung Center, Department of Medicine, University of Vermont College of Medicine, Burlington, VT, United States of America
| | - Jason H. T. Bates
- Vermont Lung Center, Department of Medicine, University of Vermont College of Medicine, Burlington, VT, United States of America
| | - Gregory S. Roy
- Vermont Lung Center, Department of Medicine, University of Vermont College of Medicine, Burlington, VT, United States of America
| | - Adele J. Julianelle
- Vermont Lung Center, Department of Medicine, University of Vermont College of Medicine, Burlington, VT, United States of America
| | - Chantel Charlebois
- Vermont Lung Center, Department of Medicine, University of Vermont College of Medicine, Burlington, VT, United States of America
| | - Bela Suki
- Department of Biomedical Engineering, Boston University, Boston, MA, United States of America
| | - Bradford J. Smith
- Department of Bioengineering, University of Colorado Denver, Aurora, CO, United States of America
- * E-mail:
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48
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Smith BJ, Bartolak-Suki E, Suki B, Roy GS, Hamlington KL, Charlebois CM, Bates JHT. Linking Ventilator Injury-Induced Leak across the Blood-Gas Barrier to Derangements in Murine Lung Function. Front Physiol 2017; 8:466. [PMID: 28736528 PMCID: PMC5500660 DOI: 10.3389/fphys.2017.00466] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 06/19/2017] [Indexed: 01/10/2023] Open
Abstract
Mechanical ventilation is vital to the management of acute respiratory distress syndrome, but it frequently leads to ventilator-induced lung injury (VILI). Understanding the pathophysiological processes involved in the development of VILI is an essential prerequisite for improving lung-protective ventilation strategies. The goal of this study was to relate the amount and nature of material accumulated in the airspaces to biomarkers of injury and the derecruitment behavior of the lung in VILI. Forty-nine BALB/c mice were mechanically ventilated with combinations of tidal volume and end-expiratory pressures to produce varying degrees of overdistension and atelectasis while lung function was periodically assessed. Total protein, serum protein, and E-Cadherin levels were measured in bronchoalveolar lavage fluid (BALF). Tissue injury was assessed by histological scoring. We found that both high tidal volume and zero positive end-expiratory pressure were necessary to produce significant VILI. Increased BALF protein content was correlated with increased lung derecruitability, elevated peak pressures, and histological evidence of tissue injury. Blood derived molecules were present in the BALF in proportion to histological injury scores and epithelial injury, reflected by E-Cadherin levels in BALF. We conclude that repetitive recruitment is an important factor in the pathogenesis of VILI that exacerbates injury associated with tidal overdistension. Furthermore, the dynamic mechanical behavior of the injured lung provides a means to assess both the degree of tissue injury and the nature and amount of blood-derived fluid and proteins that accumulate in the airspaces.
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Affiliation(s)
- Bradford J Smith
- Department of Bioengineering, Anschutz Medical Campus, University of Colorado DenverAurora, CO, United States
| | | | - Bela Suki
- Department of Biomedical Engineering, Boston UniversityBoston, MA, United States
| | - Gregory S Roy
- Department of Medicine, Vermont Lung Center, Larner College of Medicine at The University of VermontBurlington, VT, United States
| | - Katharine L Hamlington
- Department of Medicine, Vermont Lung Center, Larner College of Medicine at The University of VermontBurlington, VT, United States
| | - Chantel M Charlebois
- Department of Medicine, Vermont Lung Center, Larner College of Medicine at The University of VermontBurlington, VT, United States
| | - Jason H T Bates
- Department of Medicine, Vermont Lung Center, Larner College of Medicine at The University of VermontBurlington, VT, United States
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Sampson BJ, Marshall DA, Smith BJ, Stringer SJ, Werle CT, Magee DJ, Adamczyk JJ. Erythritol and Lufenuron Detrimentally Alter Age Structure of Wild Drosophila suzukii (Diptera: Drosophilidae) Populations in Blueberry and Blackberry. J Econ Entomol 2017; 110:530-534. [PMID: 28334255 DOI: 10.1093/jee/tow307] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Indexed: 06/06/2023]
Abstract
We report on the efficacy of 0.5 M (61,000 ppm) erythritol (E) in Truvia Baking Blend, 10 ppm lufenuron (L), and their combination (LE) to reduce egg and larval densities of wild populations of Drosophila suzukii (Matsumura) infesting fields of rabbiteye blueberries (Vaccinium virgatum) and blackberries (Rubus sp.). Formulations included the active ingredients (lufenuron, erythritol, or both), sugar (in control and erythritol treatments), and Dawn hand-soap applied to plants with pressurized 3-gallon garden spray tanks. The three chemical treatments (E, L, and LE) had no effect on D. suzukii ovipositing in blackberry and blueberry fruit, but they did reduce larval infestation by 75%, particularly densities of first and second instars. Erythritol and lufenuron were equally efficacious compounds as a D. suzukii ovicide and larvicide, but they did not display additive or synergistic activity. Extremely high larval mortality in control fruits show an age structure heavily skewed toward egg output.
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Affiliation(s)
- B J Sampson
- USDA-ARS Thad Cochran Southern Horticultural Laboratory, 810 Hwy., 26 West, Poplarville, MS 39470 (; ; ; ; ; ; )
| | - D A Marshall
- USDA-ARS Thad Cochran Southern Horticultural Laboratory, 810 Hwy., 26 West, Poplarville, MS 39470 (; ; ; ; ; ; )
| | - B J Smith
- USDA-ARS Thad Cochran Southern Horticultural Laboratory, 810 Hwy., 26 West, Poplarville, MS 39470 (; ; ; ; ; ; )
| | - S J Stringer
- USDA-ARS Thad Cochran Southern Horticultural Laboratory, 810 Hwy., 26 West, Poplarville, MS 39470 (; ; ; ; ; ; )
| | - C T Werle
- USDA-ARS Thad Cochran Southern Horticultural Laboratory, 810 Hwy., 26 West, Poplarville, MS 39470 (; ; ; ; ; ; )
| | - D J Magee
- USDA-ARS Thad Cochran Southern Horticultural Laboratory, 810 Hwy., 26 West, Poplarville, MS 39470 (; ; ; ; ; ; )
| | - J J Adamczyk
- USDA-ARS Thad Cochran Southern Horticultural Laboratory, 810 Hwy., 26 West, Poplarville, MS 39470 (; ; ; ; ; ; )
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50
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Abstract
The possibility that stem cells might be used to regenerate tissue is now being investigated for a variety of organs, but these investigations are still essentially exploratory and have few predictive tools available to guide experimentation. We propose, in this study, that the field of lung tissue regeneration might be better served by predictive tools that treat stem cells as agents that obey certain rules of behavior governed by both their phenotype and their environment. Sufficient knowledge of these rules of behavior would then, in principle, allow lung tissue development to be simulated computationally. Toward this end, we developed a simple agent-based computational model to simulate geographic patterns of cells seeded onto a lung scaffold. Comparison of the simulated patterns to those observed experimentally supports the hypothesis that mesenchymal stem cells proliferate preferentially toward the scaffold boundary, whereas alveolar epithelial cells do not. This demonstrates that a computational model of this type has the potential to assist in the discovery of rules of cellular behavior.
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Affiliation(s)
- Joshua J Pothen
- University of Vermont College of Medicine , Burlington, Vermont
| | | | - Darcy Wagner
- Comprehensive Pneumology Center , Ludwig-Maximilians-Universität, Universitätsklinikum Grosshadern, und Helmholtz Zentrum München, München, Germany
| | - Daniel J Weiss
- University of Vermont College of Medicine , Burlington, Vermont
| | | | - Baoshun Ma
- University of Vermont College of Medicine , Burlington, Vermont
| | - Jason H T Bates
- University of Vermont College of Medicine , Burlington, Vermont
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