Hypoxia inducible factor-1a in human emphysema lung tissue

The pathobiology of chronic obstructive pulmonary disease (COPD) is not completely understood. The aim of this study was to assess the expression of hypoxia inducible factor (HIF)-1a in lung tissue from patients with COPD/emphysema. Lung tissue samples from 26 patients were included in this study. Seven samples were obtained from patients with normal lung function, the remainder of the samples were taken from patients with moderate COPD (n56; stage I and II Global Initiative for Chronic Obstructive Lung Disease classification) and severe COPD (n513; stage III and IV). We analysed mRNA and protein expression in the lung tissue samples and found that: 1) HIF-1a and histone deacetylase 2 proteins were significantly decreased and were correlated; 2) HIF-1a and vascular endothelial growth factor (VEGF) proteins, and forced expiratory volume in 1 s % predicted were correlated in all patients; 3) the changes in VEGF and HIF-1a protein levels in all patients were not age-related and not related to the pack-yr smoking history; and 4) the reduced HIF-1a protein expression was seen in lung endothelial cells and alveolar septal cells by immunohistochemistry. In conclusion, reduced expression of HIF-1a protein in severe COPD is consistent with the concept of a lung structure maintenance programme which is impaired on a molecular level.