1. Myofibroblasts are increased in the lung parenchyma in asthma
- Author
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John C. Butt, Bianca Bergamo de Araujo-Paulino, Stacey R. Boser, Francis H. Y. Green, Elia Garcia Caldini, Thais Mauad, Grishma Shrestha, Ian Mitchell, Alan James, Margaret M. Kelly, and Andrea Chiu
- Subjects
Male ,0301 basic medicine ,Pathology ,Pulmonology ,lcsh:Medicine ,Cell Count ,Biochemistry ,Basement Membrane ,Contractile Proteins ,0302 clinical medicine ,Animal Cells ,Medicine and Health Sciences ,Medicine ,Myofibroblasts ,lcsh:Science ,Musculoskeletal System ,Lung ,Connective Tissue Cells ,Smooth Muscles ,Multidisciplinary ,biology ,Muscles ,Middle Aged ,respiratory system ,TÉCNICAS DE DIAGNÓSTICO DO SISTEMA RESPIRATÓRIO ,Extracellular Matrix ,3. Good health ,Peripheral ,medicine.anatomical_structure ,Connective Tissue ,Female ,Cellular Types ,Anatomy ,Cellular Structures and Organelles ,Myofibroblast ,Research Article ,Adult ,medicine.medical_specialty ,Adolescent ,Myocytes, Smooth Muscle ,Alpha (ethology) ,Young Adult ,03 medical and health sciences ,Parenchyma ,Humans ,Parenchymal Tissue ,Asthma ,Basement membrane ,business.industry ,lcsh:R ,Biology and Life Sciences ,Proteins ,Cell Biology ,Fibroblasts ,medicine.disease ,Actins ,Elastin ,respiratory tract diseases ,Cytoskeletal Proteins ,Biological Tissue ,030104 developmental biology ,030228 respiratory system ,Cardiovascular Anatomy ,biology.protein ,Blood Vessels ,lcsh:Q ,business ,Collagens - Abstract
Background Increased airway smooth muscle is observed in large and small airways in asthma. Semi-quantitative estimates suggest that cells containing alpha smooth muscle actin (α-SMA) are also increased in the lung parenchyma. This study quantified and characterized α-SMA positive cells (α-SMA+) in the lung parenchyma of non-asthmatic and asthmatic individuals. Methods Post-mortem sections of peripheral lung from cases of fatal asthma (FA), persons with asthma dying of non-respiratory causes (NFA) and non-asthma control subjects (NAC) were stained for α-SMA, quantified using point-counting and normalised to alveolar basement membrane length and interstitial area. Results α-SMA+ fractional area was increased in alveolar parenchyma in both FA (14.7 ± 2.8% of tissue area) and NFA (13.0 ± 1.2%), compared with NAC (7.4 ± 2.4%), p < 0.05 The difference was greater in upper lobes compared with lower lobes (p < 0.01) in both asthma groups. Similar changes were observed in alveolar ducts and alveolar walls. The electron microscopic features of the α-SMA+ cells were characteristic of myofibroblasts. Conclusions We conclude that in asthma there is a marked increase in α-SMA+ myofibroblasts in the lung parenchyma. The physiologic consequences of this increase are unknown.
- Published
- 2017