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Appuhn SV, Siebert S, Myti D, Wrede C, Surate Solaligue DE, Pérez-Bravo D, Brandenberger C, Schipke J, Morty RE, Grothausmann R, Mühlfeld C. Capillary Changes Precede Disordered Alveolarization in a Mouse Model of Bronchopulmonary Dysplasia. Am J Respir Cell Mol Biol 2021; 65:81-91. [PMID: 33784484 DOI: 10.1165/rcmb.2021-0004oc] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Bronchopulmonary dysplasia (BPD), the most common sequela of preterm birth, is a severe disorder of the lung that is often associated with long-lasting morbidity. A hallmark of BPD is the disruption of alveolarization, whose pathogenesis is incompletely understood. Here, we tested the vascular hypothesis that disordered vascular development precedes the decreased alveolarization associated with BPD. Neonatal mouse pups were exposed to 7, 14, or 21 days of normoxia (21% O2) or hyperoxia (85% O2) with n = 8-11 for each group. The right lungs were fixed by vascular perfusion and investigated by design-based stereology or three-dimensional reconstruction of data sets obtained by serial block-face scanning EM. The alveolar capillary network of hyperoxia-exposed mice was characterized by rarefaction, partially altered geometry, and widening of capillary segments as shown by three-dimensional reconstruction. Stereology revealed that the development of alveolar epithelium and capillary endothelium was decreased in hyperoxia-exposed mice; however, the time course of these effects was different. That the surface area of the alveolar epithelium was smaller in hyperoxia-exposed mice first became evident at Day 14. In contrast, the surface area of the endothelium was reduced in hyperoxia-exposed mouse pups at Day 7. The thickness of the air-blood barrier decreased during postnatal development in normoxic mice, whereas it increased in hyperoxic mice. The endothelium and the septal connective tissue made appreciable contributions to the thickened septa. In conclusion, the present study provides clear support for the idea that the stunted alveolarization follows the disordered microvascular development, thus supporting the vascular hypothesis of BPD.
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Affiliation(s)
- Svenja V Appuhn
- 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, Germany
| | - Sara Siebert
- 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, Germany
| | - Despoina Myti
- Department of Lung Development and Remodelling, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany.,Department of Internal Medicine (Pulmonology), Member of the German Center for Lung Research (DZL), University of Giessen and Marburg Lung Center, Giessen, Germany; and
| | - Christoph Wrede
- Institute of Functional and Applied Anatomy and.,Research Core Unit Electron Microscopy, Hannover Medical School, Hannover, Germany.,Biomedical Research in Endstage and Obstructive Lung Disease Hannover, Member of the German Center for Lung Research (DZL), Hannover, Germany
| | - David E Surate Solaligue
- Department of Lung Development and Remodelling, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany.,Department of Internal Medicine (Pulmonology), Member of the German Center for Lung Research (DZL), University of Giessen and Marburg Lung Center, Giessen, Germany; and
| | - David Pérez-Bravo
- Department of Lung Development and Remodelling, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany.,Department of Internal Medicine (Pulmonology), Member of the German Center for Lung Research (DZL), University of Giessen and Marburg Lung Center, Giessen, Germany; and
| | - Christina Brandenberger
- 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, Germany
| | - Julia Schipke
- 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, Germany
| | - Rory E Morty
- Department of Lung Development and Remodelling, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany.,Department of Internal Medicine (Pulmonology), Member of the German Center for Lung Research (DZL), University of Giessen and Marburg Lung Center, Giessen, Germany; and
| | - Roman Grothausmann
- 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, Germany.,Faculty of Engineering and Health, HAWK University of Applied Sciences and Arts, Göttingen, Germany
| | - Christian Mühlfeld
- Institute of Functional and Applied Anatomy and.,Research Core Unit Electron Microscopy, Hannover Medical School, Hannover, Germany.,Biomedical Research in Endstage and Obstructive Lung Disease Hannover, Member of the German Center for Lung Research (DZL), Hannover, Germany
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