A decreased clearance of apoptotic cells (efferocytosis) by alveolar macrophages (AM) may
contribute to inflammation in emphysema. The up-regulation of ceramides in response to
cigarette smoking (CS) has been linked to AM accumulation and increased detection of
apoptotic alveolar epithelial and endothelial cells in lung parenchyma. We hypothesized that
ceramides inhibit the AM phagocytosis of apoptotic cells. Release of endogenous ceramides
via sphingomyelinase or exogenous ceramide treatments dose-dependently impaired …