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Boyuklieva R, Zagorchev P, Pilicheva B. Computational, In Vitro, and In Vivo Models for Nose-to-Brain Drug Delivery Studies. Biomedicines 2023; 11:2198. [PMID: 37626694 PMCID: PMC10452071 DOI: 10.3390/biomedicines11082198] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 07/27/2023] [Accepted: 08/02/2023] [Indexed: 08/27/2023] Open
Abstract
Direct nose-to-brain drug delivery offers the opportunity to treat central nervous system disorders more effectively due to the possibility of drug molecules reaching the brain without passing through the blood-brain barrier. Such a delivery route allows the desired anatomic site to be reached while ensuring drug effectiveness, minimizing side effects, and limiting drug losses and degradation. However, the absorption of intranasally administered entities is a complex process that considerably depends on the interplay between the characteristics of the drug delivery systems and the nasal mucosa. Various preclinical models (in silico, in vitro, ex vivo, and in vivo) are used to study the transport of drugs after intranasal administration. The present review article attempts to summarize the different computational and experimental models used so far to investigate the direct delivery of therapeutic agents or colloidal carriers from the nasal cavity to the brain tissue. Moreover, it provides a critical evaluation of the data available from different studies and identifies the advantages and disadvantages of each model.
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Affiliation(s)
- Radka Boyuklieva
- Department of Pharmaceutical Sciences, Faculty of Pharmacy, Medical University of Plovdiv, 4002 Plovdiv, Bulgaria;
- Research Institute, Medical University of Plovdiv, 4002 Plovdiv, Bulgaria;
| | - Plamen Zagorchev
- Research Institute, Medical University of Plovdiv, 4002 Plovdiv, Bulgaria;
- Department of Medical Physics and Biophysics, Faculty of Pharmacy, Medical University of Plovdiv, 4002 Plovdiv, Bulgaria
| | - Bissera Pilicheva
- Department of Pharmaceutical Sciences, Faculty of Pharmacy, Medical University of Plovdiv, 4002 Plovdiv, Bulgaria;
- Research Institute, Medical University of Plovdiv, 4002 Plovdiv, Bulgaria;
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Effect of MDI Actuation Timing on Inhalation Dosimetry in a Human Respiratory Tract Model. Pharmaceuticals (Basel) 2022; 15:ph15010061. [PMID: 35056118 PMCID: PMC8777964 DOI: 10.3390/ph15010061] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 12/28/2021] [Accepted: 12/31/2021] [Indexed: 01/02/2023] Open
Abstract
Accurate knowledge of the delivery of locally acting drug products, such as metered-dose inhaler (MDI) formulations, to large and small airways is essential to develop reliable in vitro/in vivo correlations (IVIVCs). However, challenges exist in modeling MDI delivery, due to the highly transient multiscale spray formation, the large variability in actuation–inhalation coordination, and the complex lung networks. The objective of this study was to develop/validate a computational MDI-releasing-delivery model and to evaluate the device actuation effects on the dose distribution with the newly developed model. An integrated MDI–mouth–lung (G9) geometry was developed. An albuterol MDI with the chlorofluorocarbon propellant was simulated with polydisperse aerosol size distribution measured by laser light scatter and aerosol discharge velocity derived from measurements taken while using a phase Doppler anemometry. The highly transient, multiscale airflow and droplet dynamics were simulated by using large eddy simulation (LES) and Lagrangian tracking with sufficiently fine computation mesh. A high-speed camera imaging of the MDI plume formation was conducted and compared with LES predictions. The aerosol discharge velocity at the MDI orifice was reversely determined to be 40 m/s based on the phase Doppler anemometry (PDA) measurements at two different locations from the mouthpiece. The LES-predicted instantaneous vortex structures and corresponding spray clouds resembled each other. There are three phases of the MDI plume evolution (discharging, dispersion, and dispensing), each with distinct features regardless of the actuation time. Good agreement was achieved between the predicted and measured doses in both the device, mouth–throat, and lung. Concerning the device–patient coordination, delayed MDI actuation increased drug deposition in the mouth and reduced drug delivery to the lung. Firing MDI before inhalation was found to increase drug loss in the device; however, it also reduced mouth–throat loss and increased lung doses in both the central and peripheral regions.
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Talaat M, Si XA, Dong H, Xi J. Leveraging statistical shape modeling in computational respiratory dynamics: Nanomedicine delivery in remodeled airways. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2021; 204:106079. [PMID: 33831725 DOI: 10.1016/j.cmpb.2021.106079] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 03/29/2021] [Indexed: 06/12/2023]
Abstract
BACKGROUND AND OBJECTIVE Accurate knowledge of the delivered doses to the diseased site in the respiratory tract is crucial to elicit desired therapeutic outcomes. However, such information is still difficult to obtain due to inaccessibility for measurement or visualization, complex network structure, and challenges in reconstructing lung geometries with disease-invoked airway remodeling. This study presents a novel method to simulate the airway remodeling in a mouth-lung geometry extending to G9. METHODS Statistical shape modeling was used to extract morphological features from a lung geometry database and four new models (i.e., M1-M4) were generated with parameter-controlled dilated/constricted bronchioles in the left-lower (LL) lung. The variations in airflow and particle deposition due to the airway remodeling were simulated using a well-tested k-ω turbulence model and a Lagrangian tracking approach. RESULTS Significant variations in flow partitions between the lower and upper lobes of the left lung, as well as between the left and right lungs. The flow partition into the LL lobe varied by 10-fold between the most dilated and constricted models in this study. Significantly lower doses were also predicted on the surface of the constricted LL bronchioles G4-G9, as well as into the peripheral airways beyond G9. However, the total dosimetry in the mouth-lung geometry (up to G9) exhibited low sensitivity to the LL lobar remodeling. Results in this study suggest that the optimal nanomedicine should be 2-10 nm in diameter if targeted at the constricted bronchioles G4-G9 as in topical inhalation therapy but should be larger than 20 nm if targeted at the alveolar region as in systemic therapy. CONCLUSIONS This study highlights the large dose variability from local airway remodeling and the need to consider these variations in the treatment planning for pneumonia and other obstructive respiratory diseases.
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Affiliation(s)
- Mohamed Talaat
- Department of Biomedical Engineering, University of Massachusetts, Lowell, MA, U.S.A.
| | - Xiuhua April Si
- Department of Aerospace, Industrial, and Mechanical Engineering, California Baptist University, Riverside, CA, U.S.A.
| | - Haibo Dong
- Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA, U.S.A.
| | - Jinxiang Xi
- Department of Biomedical Engineering, University of Massachusetts, Lowell, MA, U.S.A.
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Si XA, Talaat M, Su WC, Xi J. Inhalation dosimetry of nasally inhaled respiratory aerosols in the human respiratory tract with locally remodeled conducting lungs. Inhal Toxicol 2021; 33:143-159. [PMID: 33870835 DOI: 10.1080/08958378.2021.1912860] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Objective: Respiratory diseases are often accompanied by alterations to airway morphology. However, inhalation dosimetry data in remodeled airways are scarce due to the challenges in reconstructing diseased respiratory morphologies. This study aims to study the airway remodeling effects on the inhalation dosimetry of nasally inhaled nanoparticles in a nose-lung geometry that extends to G9 (ninth generation).Materials and methods: Statistical shape modeling was used to develop four diseased lung models with varying levels of bronchiolar dilation/constriction in the left-lower (LL) lobe (i.e. M1-M4). Respiratory airflow and particle deposition were simulated using a low Reynolds number k-ω turbulence model and a Lagrangian tracking approach.Results: Significant discrepancies were observed in the flow partitions between the left and right lungs, as well as between the lower and upper lobes of the left lung, which changed by 10-fold between the most dilated and constricted models.Much lower doses were predicted on the surface of the constricted LL bronchioles G4-G9, as well as into the peripheral airways beyond G9 of the LL lung. However, the LL lobar remodeling had little effect on the dosimetry in the nasopharynx, as well as on the total dosimetry in the nose-lung geometry (up to G9).Conclusion: It is suggested that airway remodeling may pose a higher viral infection risk to the host by redistributing the inhaled viruses to healthy lung lobes. Airway remodeling effects should also be considered in the treatment planning of inhalation therapies, not only because of the dosimetry variation from altered lung morphology but also its evolution as the disease progresses.
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Affiliation(s)
- Xiuhua April Si
- Department of Mechanical Engineering, California Baptist University, Riverside, CA, USA
| | - Mohamed Talaat
- Department of Biomedical Engineering, University of Massachusetts, Lowell, MA, USA
| | - Wei-Chung Su
- Department of Epidemiology, Human Genetics, and Environmental Science, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Jinxiang Xi
- Department of Biomedical Engineering, University of Massachusetts, Lowell, MA, USA
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Khan A, Markus A, Rittmann T, Albers J, Alves F, Hülsmann S, Dullin C. Simple low dose radiography allows precise lung volume assessment in mice. Sci Rep 2021; 11:4163. [PMID: 33602964 PMCID: PMC7893164 DOI: 10.1038/s41598-021-83319-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 01/08/2021] [Indexed: 02/07/2023] Open
Abstract
X-ray based lung function (XLF) as a planar method uses dramatically less X-ray dose than computed tomography (CT) but so far lacked the ability to relate its parameters to pulmonary air volume. The purpose of this study was to calibrate the functional constituents of XLF that are biomedically decipherable and directly comparable to that of micro-CT and whole-body plethysmography (WBP). Here, we developed a unique set-up for simultaneous assessment of lung function and volume using XLF, micro-CT and WBP on healthy mice. Our results reveal a strong correlation of lung volumes obtained from radiographic XLF and micro-CT and demonstrate that XLF is superior to WBP in sensitivity and precision to assess lung volumes. Importantly, XLF measurement uses only a fraction of the radiation dose and acquisition time required for CT. Therefore, the redefined XLF approach is a promising tool for preclinical longitudinal studies with a substantial potential of clinical translation.
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Affiliation(s)
- Amara Khan
- Translational Molecular Imaging, Max-Planck-Institute for Experimental Medicine, Hermann-Rein-Straße 3, 37075, Göttingen, Germany
| | - Andrea Markus
- Translational Molecular Imaging, Max-Planck-Institute for Experimental Medicine, Hermann-Rein-Straße 3, 37075, Göttingen, Germany
| | - Thomas Rittmann
- 4th Physical Institute - Solids and Nanostructures, University of Göttingen, Friedrich-Hund-Platz 1, 37077, Göttingen, Germany
| | - Jonas Albers
- Translational Molecular Imaging, Max-Planck-Institute for Experimental Medicine, Hermann-Rein-Straße 3, 37075, Göttingen, Germany
- Institute for Diagnostic and Interventional Radiology, University Medical Center Göttingen, Robert-Koch-Straße 40, 37075, Göttingen, Germany
| | - Frauke Alves
- Translational Molecular Imaging, Max-Planck-Institute for Experimental Medicine, Hermann-Rein-Straße 3, 37075, Göttingen, Germany
- Institute for Diagnostic and Interventional Radiology, University Medical Center Göttingen, Robert-Koch-Straße 40, 37075, Göttingen, Germany
- Clinic for Hematology and Medical Oncology, University Medical Center Göttingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany
| | - Swen Hülsmann
- Clinic for Anesthesiology, University Medical Center Göttingen, Humboldtallee 23, 37073, Göttingen, Germany
| | - Christian Dullin
- Translational Molecular Imaging, Max-Planck-Institute for Experimental Medicine, Hermann-Rein-Straße 3, 37075, Göttingen, Germany.
- Institute for Diagnostic and Interventional Radiology, University Medical Center Göttingen, Robert-Koch-Straße 40, 37075, Göttingen, Germany.
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Lu J, Xi J, Langenderfer JE. Sensitivity Analysis and Uncertainty Quantification in Pulmonary Drug Delivery of Orally Inhaled Pharmaceuticals. J Pharm Sci 2017. [DOI: 10.1016/j.xphs.2017.06.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Schepens T, Cammu G, Maes S, Desmedt B, Vos W, Deseure K. [Functional respiratory imaging after neostigmine- or sugammadex-enhanced recovery from neuromuscular blockade in the anesthetised rat: a randomised controlled pilot study]. Rev Bras Anestesiol 2017; 67:443-449. [PMID: 28526472 DOI: 10.1016/j.bjan.2017.04.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 11/23/2015] [Indexed: 12/20/2022] Open
Abstract
OBJECTIVES Reductions in diaphragm activity are associated with the postoperative development of atelectasis. Neostigmine reversal is also associated with increased atelectasis. We assessed the effects of neostigmine, sugammadex, and spontaneous reversal on regional lung ventilation and airway flow. METHODS Six Sprague-Dawley rats were paralysed with rocuronium and mechanically ventilated until recovery of the train-of-four ratio to 0.5. We administered neostigmine (0.06mg.kg-1), sugammadex (15mg.kg-1), or saline (n=2 per group). Computed tomography scans were obtained during the breathing cycle. Three-dimensional models of lung lobes were generated using functional respiratory imaging technology, and lobar volumes were calculated during the breathing cycle. The diaphragmatic surface was segmented for the end-expiratory and end-inspiratory scans. The total change in volume was reported by the lung volume change from the end-expiratory scan to the end-inspiratory scan. Chest wall movement was defined as the lung volume change minus the volume change that resulted from diaphragm excursion. RESULTS The two rats that received neostigmine exhibited a smaller relative contribution of diaphragm movement to the total change in lung volume compared with the two rats that received sugammadex or saline (chest wall contribution (%): 26.69 and 25.55 for neostigmine; -2.77 and 15.98 for sugammadex; 18.82 and 10.30 for saline). CONCLUSION This pilot study in rats demonstrated an increased relative contribution of chest wall expansion after neostigmine compared with sugammadex or saline. This smaller relative contribution of diaphragm movement may be explained by a neostigmine-induced decrease in phrenic nerve activity or by remaining occupied acetylcholine receptors after neostigmine.
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Affiliation(s)
- Tom Schepens
- Antwerp University Hospital, Department of Anesthesiology, Edegem, Bélgica
| | - Guy Cammu
- Onze-Lieve-Vrouw Ziekenhuis, Anesthesiology and Critical Care Medicine, Aalst, Bélgica.
| | - Sabine Maes
- Antwerp University Hospital, Department of Anesthesiology, Edegem, Bélgica
| | | | | | - Kristof Deseure
- University of Antwerp, Deparment of Algology, Wilrijk, Bélgica
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Ruscitti F, Ravanetti F, Essers J, Ridwan Y, Belenkov S, Vos W, Ferreira F, KleinJan A, van Heijningen P, Van Holsbeke C, Cacchioli A, Villetti G, Stellari FF. Longitudinal assessment of bleomycin-induced lung fibrosis by Micro-CT correlates with histological evaluation in mice. Multidiscip Respir Med 2017; 12:8. [PMID: 28400960 PMCID: PMC5387277 DOI: 10.1186/s40248-017-0089-0] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2016] [Accepted: 03/10/2017] [Indexed: 01/15/2023] Open
Abstract
Background The intratracheal instillation of bleomycin in mice induces early damage to alveolar epithelial cells and development of inflammation followed by fibrotic tissue changes and represents the most widely used model of pulmonary fibrosis to investigate human IPF. Histopathology is the gold standard for assessing lung fibrosis in rodents, however it precludes repeated and longitudinal measurements of disease progression and does not provide information on spatial and temporal distribution of tissue damage. Here we investigated the use of the Micro-CT technique to allow the evaluation of disease onset and progression at different time-points in the mouse bleomycin model of lung fibrosis. Micro-CT was throughout coupled with histological analysis for the validation of the imaging results. Methods In bleomycin-instilled and control mice, airways and lung morphology changes were assessed and reconstructed at baseline, 7, 14 and 21 days post-treatment based on Micro-CT images. Ashcroft score, percentage of collagen content and percentage of alveolar air area were detected on lung slides processed by histology and subsequently compared with Micro-CT parameters. Results Extent (%) of fibrosis measured by Micro-CT correlated with Ashcroft score, the percentage of collagen content and the percentage of alveolar air area (r2 = 0.91; 0.77; 0.94, respectively). Distal airway radius also correlated with the Ashcroft score, the collagen content and alveolar air area percentage (r2 = 0.89; 0.78; 0.98, respectively). Conclusions Micro-CT data were in good agreement with histological read-outs as micro-CT was able to quantify effectively and non-invasively disease progression longitudinally and to reduce the variability and number of animals used to assess the damage. This suggests that this technique is a powerful tool for understanding experimental pulmonary fibrosis and that its use could translate into a more efficient drug discovery process, also helping to fill the gap between preclinical setting and clinical practice.
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Affiliation(s)
| | - Francesca Ravanetti
- Dipartimento di Scienze Medico Veterinarie, Università di Parma, Parma, Italy
| | - Jeroen Essers
- Department of Molecular Genetics, Vascular Surgery, and Radiation Oncology, Erasmus MC, Rotterdam, The Netherlands
| | - Yanto Ridwan
- Department of Molecular Genetics, Vascular Surgery, and Radiation Oncology, Erasmus MC, Rotterdam, The Netherlands
| | | | - Wim Vos
- Fluidda NV, Kontich, Belgium
| | | | - Alex KleinJan
- Department of Pulmonary Medicine Erasmus MC, Rotterdam, The Netherlands
| | - Paula van Heijningen
- Department of Molecular Genetics, Vascular Surgery, and Radiation Oncology, Erasmus MC, Rotterdam, The Netherlands
| | | | - Antonio Cacchioli
- Dipartimento di Scienze Medico Veterinarie, Università di Parma, Parma, Italy
| | | | - Franco Fabio Stellari
- Chiesi S.p.A., Pre-Clinical R & D, Parma, Italy.,Chiesi Farmaceutici, Pharmacology & Toxicology Department Corporate Pre-Clinical R & D, Largo Belloli, 11/A, Parma, 43122 Italy
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Wang H, Sebrié C, Ruaud J, Guillot G, Bouazizi K, Willoquet G, Maître X, Darrasse L, de Rochefort L. Aerosol deposition in the lungs of spontaneously breathing rats using Gd‐DOTA‐based contrast agents and ultra‐short echo time MRI at 1.5 Tesla. Magn Reson Med 2015; 75:594-605. [DOI: 10.1002/mrm.25617] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Revised: 11/22/2014] [Accepted: 12/16/2014] [Indexed: 01/05/2023]
Affiliation(s)
- Hongchen Wang
- Imagerie par Résonance Magnétique Médicale et Multi‐Modalités (UMR8081)IR4M, Univ. Paris‐Sud, CNRSOrsay France
| | - Catherine Sebrié
- Imagerie par Résonance Magnétique Médicale et Multi‐Modalités (UMR8081)IR4M, Univ. Paris‐Sud, CNRSOrsay France
| | - Jean‐Pierre Ruaud
- Imagerie par Résonance Magnétique Médicale et Multi‐Modalités (UMR8081)IR4M, Univ. Paris‐Sud, CNRSOrsay France
| | - Geneviève Guillot
- Imagerie par Résonance Magnétique Médicale et Multi‐Modalités (UMR8081)IR4M, Univ. Paris‐Sud, CNRSOrsay France
| | - Khaoula Bouazizi
- Imagerie par Résonance Magnétique Médicale et Multi‐Modalités (UMR8081)IR4M, Univ. Paris‐Sud, CNRSOrsay France
| | - Georges Willoquet
- Imagerie par Résonance Magnétique Médicale et Multi‐Modalités (UMR8081)IR4M, Univ. Paris‐Sud, CNRSOrsay France
| | - Xavier Maître
- Imagerie par Résonance Magnétique Médicale et Multi‐Modalités (UMR8081)IR4M, Univ. Paris‐Sud, CNRSOrsay France
| | - Luc Darrasse
- Imagerie par Résonance Magnétique Médicale et Multi‐Modalités (UMR8081)IR4M, Univ. Paris‐Sud, CNRSOrsay France
| | - Ludovic de Rochefort
- Imagerie par Résonance Magnétique Médicale et Multi‐Modalités (UMR8081)IR4M, Univ. Paris‐Sud, CNRSOrsay France
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Bauer C, Krueger MA, Lamm WJ, Smith BJ, Glenny RW, Beichel RR. Airway tree segmentation in serial block-face cryomicrotome images of rat lungs. IEEE Trans Biomed Eng 2013; 61:119-30. [PMID: 23955692 DOI: 10.1109/tbme.2013.2277936] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A highly automated method for the segmentation of airways in the serial block-face cryomicrotome images of rat lungs is presented. First, a point inside of the trachea is manually specified. Then, a set of candidate airway centerline points is automatically identified. By utilizing a novel path extraction method, a centerline path between the root of the airway tree and each point in the set of candidate centerline points is obtained. Local disturbances are robustly handled by a novel path extraction approach, which avoids the shortcut problem of standard minimum cost path algorithms. The union of all centerline paths is utilized to generate an initial airway tree structure, and a pruning algorithm is applied to automatically remove erroneous subtrees or branches. Finally, a surface segmentation method is used to obtain the airway lumen. The method was validated on five image volumes of Sprague-Dawley rats. Based on an expert-generated independent standard, an assessment of airway identification and lumen segmentation performance was conducted. The average of airway detection sensitivity was 87.4% with a 95% confidence interval (CI) of (84.9, 88.6)%. A plot of sensitivity as a function of airway radius is provided. The combined estimate of airway detection specificity was 100% with a 95% CI of (99.4, 100)%. The average number and diameter of terminal airway branches was 1179 and 159 μm, respectively. Segmentation results include airways up to 31 generations. The regression intercept and slope of airway radius measurements derived from final segmentations were estimated to be 7.22 μm and 1.005, respectively. The developed approach enables the quantitative studies of physiology and lung diseases in rats, requiring detailed geometric airway models.
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Oakes JM, Scadeng M, Breen EC, Marsden AL, Darquenne C. Rat airway morphometry measured from in situ MRI-based geometric models. J Appl Physiol (1985) 2012; 112:1921-31. [PMID: 22461437 DOI: 10.1152/japplphysiol.00018.2012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Rodents have been widely used to study the environmental or therapeutic impact of inhaled particles. Knowledge of airway morphometry is essential in assessing geometric influence on aerosol deposition and in developing accurate lung models of aerosol transport. Previous morphometric studies of the rat lung performed ex situ provided high-resolution measurements (50-125 μm). However, it is unclear how the overall geometry of these casts might have differed from the natural in situ appearance. In this study, four male Wistar rat (268 ± 14 g) lungs were filled sequentially with perfluorocarbon and phosphate-buffered saline before being imaged in situ in a 7-T magnetic resonance (MR) scanner at a resolution of 0.2 × 0.2 × 0.27 mm. Airway length, diameter, gravitational, bifurcation, and rotational angles were measured for the first four airway generations from 3D geometric models built from the MR images. Minor interanimal variability [expressed by the relative standard deviation RSD (=SD/mean)] was found for length (0.18 ± 0.07), diameter (0.15 ± 0.15), and gravitational angle (0.12 ± 0.06). One rat model was extended to 16 airway generations. Organization of the airways using a diameter-defined Strahler ordering method resulted in lower interorder variability than conventional generation-based grouping for both diameter (RSD = 0.12 vs. 0.42) and length (0.16 vs. 0.67). Gravitational and rotational angles averaged 82.9 ± 37.9° and 53.6 ± 24.1°, respectively. Finally, the major daughter branch bifurcated at a smaller angle (19.3 ± 14.6°) than the minor branch (60.5 ± 19.4°). These data represent the most comprehensive set of rodent in situ measurements to date and can be used readily in computational studies of lung function and aerosol exposure.
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Affiliation(s)
- Jessica M Oakes
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA, USA
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Ahmed A, Prime D, Burnell PKP, Högger P. Development of an in vitro model to assess deposition of aerosol particles in a representative replica of the rat's respiratory tract. J Aerosol Med Pulm Drug Deliv 2012; 25:169-78. [PMID: 22280010 DOI: 10.1089/jamp.2011.0902] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Small rodents continue to be the mainstay for the assessment of pharmacological and toxicological data of inhaled therapeutics. For meaningful interpretation of the results information about deposition of aerosol particles in the respiratory tract is warranted, but not trivial to obtain for animals with nose-only aerosol exposure. The purpose of this study was to develop and evaluate a general method to characterize the deposition of inhaled test particles in an in vitro model (IVR) of the rat's respiratory tract. METHODS A highly detailed, realistic and representative image using micro-CT scanning technology was obtained and the generated morphological data was used to construct a plastic replica of the average rat respiratory tract. The model was connected to a rodent ventilator, which allowed the breathing frequency (f, min(-1)) and tidal volume (V(T), mL) to be varied as required. Polydisperse fluorescent microsphere particles with an average mass median aerodynamic diameter (MMAD) of 3.1 μm and geometric standard deviation (GSD) of 2.2 μm were used as model compound. RESULTS Comparison of the experimental data for total and regional deposition levels with predicted outputs using the in silico MPPD model showed reasonably good relative agreement between the two models. The predictions were closest to the experimental values when default respiratory conditions of f=102 breaths/min and V(T) of 2.0 mL were used. Moreover, the IVR model revealed good correlation with published in vivo data. CONCLUSION Using the IVR model allows an easy, fast and reasonably precise estimation of the inhaled dose in rodent inhalation studies. The IVR has the potential to be used along with live rats in inhalation exposure studies, and thus provides the unique possibility to run an internal standard for dose deposition in the respiratory tract in each inhalation experiment. This should contribute to enable a greater understanding of drug pharmacokinetics and dynamics in rats and may improve dose extrapolation from animals to humans.
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Affiliation(s)
- Arabe Ahmed
- Inhaled Product Development, GlaxoSmithKline Research and Development, Ware, United Kingdom.
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Vinchurkar S, Backer LD, Vos W, Holsbeke CV, Backer JD, Backer WD. A case series on lung deposition analysis of inhaled medication using functional imaging based computational fluid dynamics in asthmatic patients: effect of upper airway morphology and comparison with in vivo data. Inhal Toxicol 2012; 24:81-8. [PMID: 22260527 DOI: 10.3109/08958378.2011.644351] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
CONTEXT Asthma affects 20 million Americans resulting in an economic burden of approximately $18 billion in the US alone (Allergies and Asthma Foundation 2000; National Center for Environmental Health (NCEH) 1999). Research studies based on differences in patient-specific airway morphology for asthma and the associated effect on deposition of inhaled aerosols are currently not available in the literature. Therefore, the role of morphological variations such as upper airway (extrathoracic) occlusion is not well documented. OBJECTIVE Functional imaging based computational fluid dynamics (CFD) of the respiratory airways for five asthmatic subjects is performed in this study using computed tomography (CT) based patient-specific airway models and boundary conditions. METHODS CT scans for 5 asthma patients were used to reconstruct 3D lung models using segmentation software. An averaged inhalation profile and patient-specific lobar flow distribution were used to perform the simulation. The simulations were used to obtain deposition for BDP/Formoterol® HFA pMDI in the patient-specific airway models. RESULTS The lung deposition obtained using CFD was in excellent agreement with available in vivo data using the same product. Specifically, CFD resulted in 30% lung deposition, whereas in vivo lung deposition was reported to be approximately 31%. CONCLUSION It was concluded that a combination of patient-specific airway models and lobar boundary conditions can be used to obtain accurate lung deposition estimates. Lower lung deposition can be expected for patients with higher extrathoracic resistance. Novel respiratory drug delivery devices need to accommodate population sub-groups based on these morphological and anatomical differences in addition to subject age.
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De Backer LA, Vos WG, Salgado R, De Backer JW, Devolder A, Verhulst SL, Claes R, Germonpré PR, De Backer WA. Functional imaging using computer methods to compare the effect of salbutamol and ipratropium bromide in patient-specific airway models of COPD. Int J Chron Obstruct Pulmon Dis 2011; 6:637-46. [PMID: 22162649 PMCID: PMC3232170 DOI: 10.2147/copd.s21917] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Salbutamol and ipratropium bromide improve lung function in patients with chronic obstructive pulmonary disease (COPD). However, their bronchodilating effect has not yet been compared in the central and distal airways. Functional imaging using computational fluid dynamics offers the possibility of making such a comparison. The objective of this study was to assess the effects of salbutamol and ipratropium bromide on the geometry and computational fluid dynamics-based resistance of the central and distal airways. METHODS Five patients with Global Initiative for Chronic Obstructive Lung Disease Stage III COPD were randomized to a single dose of salbutamol or ipratropium bromide in a crossover manner with a 1-week interval between treatments. Patients underwent lung function testing and a multislice computed tomography scan of the thorax that was used for functional imaging. Two hours after dosing, the patients again underwent lung function tests and repeat computed tomography. RESULTS Lung function parameters, including forced expiratory volume in 1 second, vital capacity, overall airway resistance, and specific airway resistance, changed significantly after administration of each product. On functional imaging, the bronchodilating effect was greater in the distal airways, with a corresponding drop in airway resistance, compared with the central airways. Salbutamol and ipratropium bromide were equally effective at first glance when looking at lung function tests, but when viewed in more detail with functional imaging, hyporesponsiveness could be shown for salbutamol in one patient. Salbutamol was more effective in the other patients. CONCLUSION This pilot study gives an innovative insight into the modes of action of salbutamol and ipratropium bromide in patients with COPD, using the new techniques of functional imaging and computational fluid dynamics.
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Affiliation(s)
- L A De Backer
- Department of Respiratory Medicine, Antwerp University Hospital, Antwerp, Belgium.
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15
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De Backer L, Vos W, Dieriks B, Daems D, Verhulst S, Vinchurkar S, Ides K, De Backer J, Germonpre P, De Backer W. The effects of long-term noninvasive ventilation in hypercapnic COPD patients: a randomized controlled pilot study. Int J Chron Obstruct Pulmon Dis 2011; 6:615-24. [PMID: 22135493 PMCID: PMC3224655 DOI: 10.2147/copd.s22823] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Introduction Noninvasive ventilation (NIV) is a well-established treatment for acute-on- chronic respiratory failure in hypercapnic COPD patients. Less is known about the effects of a long-term treatment with NIV in hypercapnic COPD patients and about the factors that may predict response in terms of improved oxygenation and lowered CO2 retention. Methods In this study, we randomized 15 patients to a routine pharmacological treatment (n = 5, age 66 [standard deviation ± 6] years, FEV1 30.5 [±5.1] %pred, PaO2 65 [±6] mmHg, PaCO2 52.4 [±6.0] mmHg) or to a routine treatment and NIV (using the Synchrony BiPAP device [Respironics, Inc, Murrsville, PA]) (n = 10, age 65 [±7] years, FEV1 29.5 [±9.0] %pred, PaO2 59 [±13] mmHg, PaCO2 55.4 [±7.7] mmHg) for 6 months. We looked at arterial blood gasses, lung function parameters and performed a low-dose computed tomography of the thorax, which was later used for segmentation (providing lobe and airway volumes, iVlobe and iVaw) and post-processing with computer methods (providing airway resistance, iRaw) giving overall a functional image of the separate airways and lobes. Results In both groups there was a nonsignificant change in FEV1 (NIV group 29.5 [9.0] to 38.5 [14.6] %pred, control group 30.5 [5.1] to 36.8 [8.7] mmHg). PaCO2 dropped significantly only in the NIV group (NIV: 55.4 [7.7] → 44.5 [4.70], P = 0.0076; control: 52.4 [6.0] → 47.6 [8.2], NS). Patients actively treated with NIV developed a more inhomogeneous redistribution of mass flow than control patients. Subsequent analysis indicated that in NIV-treated patients that improve their blood gases, mass flow was also redistributed towards areas with higher vessel density and less emphysema, indicating that flow was redistributed towards areas with better perfusion. There was a highly significant correlation between the % increase in mass flow towards lobes with a blood vessel density of >9% and the increase in PaO2. Improved ventilation–perfusion match and recruitment of previously occluded small airways can explain the improvement in blood gases. Conclusion We can conclude that in hypercapnic COPD patients treated with long-term NIV over 6 months, a mass flow redistribution occurs, providing a better ventilation–perfusion match and hence better blood gases and lung function. Control patients improve homogeneously in iVaw and iRaw, without improvement in gas exchange since there is no improved ventilation/perfusion ratio or increased alveolar ventilation. These differences in response can be detected through functional imaging, which gives a more detailed report on regional lung volumes and resistances than classical lung function tests do. Possibly only patients with localized small airway disease are good candidates for long-term NIV treatment. To confirm this and to see if better arterial blood gases also lead to better health related quality of life and longer survival, we have to study a larger population.
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Affiliation(s)
- L De Backer
- Antwerp University Hospital, Department of Respiratory Medicine, Antwerp, Belgium.
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Santyr GE, Couch MJ, Lam WW, Ouriadov A, Drangova M, McCormack DG, Holdsworth DW. Comparison of hyperpolarized (3)He MRI with Xe-enhanced computed tomography imaging for ventilation mapping of rat lung. NMR IN BIOMEDICINE 2011; 24:1073-1080. [PMID: 21274963 DOI: 10.1002/nbm.1659] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2010] [Revised: 11/16/2010] [Accepted: 12/02/2010] [Indexed: 05/30/2023]
Abstract
Lung ventilation was mapped in five healthy Brown Norway rats (210-377 g) using both hyperpolarized (3)He MRI and Xe-enhanced computed tomography (Xe-CT) under similar ventilator conditions. Whole-lung measurements of ventilation r obtained with (3)He MRI were not significantly different from those obtained from Xe-CT (p = 0.1875 by Wilcoxon matched pairs test). The ventilation parameter r is defined as the fraction of refreshed gas per unit volume per breath. Regional ventilation was also measured in four regions of the lung using both methods. A two-tailed paired t-test was performed for each region, yielding p > 0.05 for all but the upper portion of the right lung. The distribution of regional ventilation was evaluated by calculating ventilation gradients in the superior/inferior (S/I) direction. The average S/I gradient obtained using the (3)He MRI method was found to be 0.17 ± 0.04 cm(-1) , whereas the average S/I gradient obtained using the Xe-CT method was found to be 0.016 ± 0.005 cm(-1) . In general, S/I ventilation gradients obtained from both methods were significantly different from each other (p = 0.0019 by two-tailed paired t-test). These regional differences in ventilation measurements may be caused by the manner in which the gas contrast agents distribute physiologically and/or by the imaging modality.
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Affiliation(s)
- Giles E Santyr
- Imaging Research Laboratories, Robarts Research Institute, London, ON, Canada.
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