Erythrocytes

Erythrocytes are responsible for transport and exchange of O2 and CO2 between the lungs and other tissues. Erythrocyte oxygenation in lung capillaries facilitates CO2 unloading, causing shrinkage and ATP release, activating endothelial cells to synthesize nitric oxide (NO), which complexes with hemoglobin. Deoxygenation in peripheral tissues initiates NO release and CO2 loading, resulting in erythrocyte swelling and vasodilation. Anemias can manifest as respiratory abnormalities, and hemoglobinopathies, such as sickle cell disease, often show pulmonary complications causing significant morbidity and mortality. Erythrocytes in an injured lung can stimulate fibroblast release of interleukin-8, enhancing inflammation. Erythrocytes contribute to lung pathology in cystic fibrosis patients, and malaria-infected erythrocytes cause alveolar and endothelial damage.