Structural alterations in erythrocytes from patients with chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is characterized by inflammation of deep lung and pulmonary hypoxemia. In order to investigate if the clinical manifestations of this disease can be correlated to specific alterations in red blood cell (RBC) morphology, the erythrocytes from 12 COPD patients and 12 control subjects were obtained and examined by scanning electron microscopy (SEM), fluorescence microscopy and electron paramagnetic resonance (EPR) spectroscopy. The results demonstrate that the RBCs from COPD patients are greatly altered with respect to control erythrocytes. Specifically, SEM analysis revealed important shape changes while light fluorescence microscopy demonstrated microfilament network (actin and spectrin) redistribution. Finally, EPR spectroscopy, using the paramagnetic spin label 5-nitroxystearate, revealed an increase in membrane order (rigidity) in the erythrocytes of COPD patients with respect to controls. When taken together and when compared to the morphological variations present in the RBCs of other ill patients (i.e., diabetics), the data presented in this report seem to suggest that changes in erythrocyte shape and rheological properties play a key role in RBC dysfunction in the course of COPD.