AUTHOR=Bai Shuang , Zhao Li TITLE=Imbalance Between Injury and Defense in the COPD Emphysematous Phenotype JOURNAL=Frontiers in Medicine VOLUME=Volume 8 - 2021 YEAR=2021 URL=https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2021.653332 DOI=10.3389/fmed.2021.653332 ISSN=2296-858X ABSTRACT=Chronic obstructive pulmonary disease (COPD) emphysematous phenotype is characterized by destruction of lung tissue structure. Patients with this phenotype usually show typical emphysema-like changes on chest CT, manifest as higher mortality and poorer prognosis, and are insensitivity to routine pharmacological therapy of COPD. However, the pathogenesis for COPD emphysematous phenotype is still unclear, resulting great difficulties for diagnosis and treatments. Injury and defense imbalance is essential in the progression of many pulmonary diseases. In this review, we focus on the pathogenesis of COPD emphysematous phenotype and discuss pathophysiological processes during disease progression from an injury and defense imbalance perspective.