Resumen de Decreased Expression of EC-SOD and Fibulin-5 in Alveolar Walls of Lungs From COPD Patients
José García-Valero, Jordi Olloquequi, Esther Rodríguez, Mireia Martín Satué, Laura Texidó, Jaume Ferrer Sancho
Introduction The aim of this study is to analyze the expression of the main oxidant scavenger superoxide dismutase (EC-SOD), its main binding protein Fibulin-5 and several oxidative and nitrosative-derived products in the lung of COPD patients and controls.
Materials and methods Lung tissue samples from 19 COPD patients and 20 control subjects were analyzed. The architecture of elastic fibres was assessed by light and electron microscope histochemical techniques, and levels of EC-SOD and fibulin-5 were analyzed by immunohistochemistry and RT-PCR. The impact of oxidative stress on the extracellular matrix was estimated by immunolocalization of 4-hydroxynonenal (4-HNE), malondialdehyde (MDA) and 3-nitrotyrosine (3-NYT) adducts.
Results Alveolar walls of COPD patients exhibited abnormal accumulations of collapsing elastic fibres, showing a pierced pattern in the amorphous component. The semiquantitative analysis revealed that COPD patients have a significantly reduced expression of both EC-SOD and fibulin-5 (0.59 ± 0.64 and 0.62 ± 0.61, respectively) in alveolar, bronchiolar and arteriolar walls compared to control subjects (1.39 ± 0.63 and 1.55 ± 0.52, respectively, p < 0.05). No significant changes in mRNA levels of these proteins were observed between groups. Among the oxidation markers, malondialdehyde was the best in distinguishing COPD patients.
Conclusions COPD patients show a reduced expression of EC-SOD and fibulin-5 in the lung interstitium. Paralleling the reduction of EC-SOD levels, the decrease of fibulin-5 expression in COPD lungs supports the hypothesis of an impaired pulmonary antioxidant response in COPD patients.
