Alveolar recruitment is a central strategy in the ventilation of patients with acute lung injury and other lung diseases associated with alveolar collapse and atelectasis. However, biomechanical insights into the opening and collapse of individual alveoli are still limited. A better understanding of alveolar recruitment and the interaction between alveoli in intact and injured lungs is of crucial relevance for the evaluation of the potential efficacy of ventilation strategies. We simulated human alveolar biomechanics in normal and injured lungs. We used a basic simulation model for the biomechanical behavior of virtual single alveoli to compute parameterized pressure-volume curves. Based on these curves, we analyzed the interaction and stability in a system composed of two alveoli. We introduced different values for surface tension and tissue properties to simulate different forms of lung injury. The data obtained predict that alveoli with identical properties can coexist with both different volumes and with equal volumes depending on the pressure. Alveoli in injured lungs with increased surface tension will collapse at normal breathing pressures. However, recruitment maneuvers and positive endexpiratory pressure can stabilize those alveoli, but coexisting unaffected alveoli might be overdistended. In injured alveoli with reduced compliance collapse is less likely, alveoli are expected to remain open, but with a smaller volume. Expanding them to normal size would overdistend coexisting unaffected alveoli. The present simulation model yields novel insights into the interaction between alveoli and may thus increase our understanding of the prospects of recruitment maneuvers in different forms of lung injury.
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http://dx.doi.org/10.1016/j.jbiomech.2009.11.025 | DOI Listing |
BMJ Open Respir Res
December 2024
Department of Design Sciences, Lund University, Lund, Sweden
Rationale: Preterm infants diagnosed with bronchopulmonary dysplasia (BPD) are thought to have fewer and larger alveoli than their term peers, but it is unclear to what degree this persists later in life.
Objectives: To investigate to what degree the distal airspaces are enlarged in adolescents born preterm and to evaluate the new Airspace Dimension Assessment (AiDA) method in investigating this group.
Methods: We investigated 41 adolescents between 15 and 17 years of age, of whom 25 were born very preterm (a gestational age <31 weeks, with a mean of 26 weeks) and 16 were term-born controls.
JCI Insight
January 2025
Department of Pediatrics, Vanderbilt University Medical Center, Nashville, United States of America.
Determining how alveoli are formed and maintained is critical to understanding lung organogenesis and regeneration after injury. To study the cellular dynamics of this critical stage of lung development, we have used scanned oblique-plane illumination microscopy of living lung slices to observe alveologenesis in real time at high resolution over several days. Contrary to the prevailing notion that alveologenesis occurs by airspace subdivision via ingrowing septa, we find that alveoli form by ballooning epithelial outgrowth supported by contracting mesenchymal ring structures.
View Article and Find Full Text PDFJ Med Biogr
January 2025
Department of Laboratory Medicine and Pathology, University of Washington, Seattle, USA.
Marcello Malpighi is widely recognized as the founder of microscopic anatomy. His seminal discoveries of the pulmonary alveoli, blood capillaries, and renal glomeruli revolutionized existing medical knowledge, earning him fame and international recognition. He discovered the respiratory system of insects and described, for the first time, their excretory apparatus.
View Article and Find Full Text PDFAm J Physiol Lung Cell Mol Physiol
January 2025
Institute of Physiology, Charité-Universitätsmedizin Berlin, Berlin, Germany.
Lung infection is one of the leading causes of morbidity and mortality worldwide. Even with appropriate antibiotic and antiviral treatment, mortality in hospitalized patients often exceeds 10%, highlighting the need for the development of new therapeutic strategies. Of late, cystic fibrosis transmembrane conductance regulator (CFTR) is - in addition to its well-established roles in the lung airway and extrapulmonary organs - increasingly recognized as a key regulator of alveolar homeostasis and defense.
View Article and Find Full Text PDFSci Transl Med
January 2025
Division of Allergy, Pulmonary, and Critical Care Medicine, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
Idiopathic pulmonary fibrosis (IPF) is a progressive interstitial lung disease in which repetitive epithelial injury and incomplete alveolar repair result in accumulation of profibrotic intermediate/transitional "aberrant" epithelial cell states. The mechanisms leading to the emergence and persistence of aberrant epithelial populations in the distal lung remain incompletely understood. By interrogating single-cell RNA sequencing (scRNA-seq) data from patients with IPF and a mouse model of repeated lung epithelial injury, we identified persistent activation of hypoxia-inducible factor (HIF) signaling in these aberrant epithelial cells.
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