The sequence polymorphism of MnSOD gene in subjects with respiratory insufficiency in COPD.

ABSTRACT

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is associated with the development of respiratory failure, which, in turn, exposes the tissues to oxidative stress, which is both a cause and a result of respiratory insufficiency. The first-line defense against oxidative stress is provided by the mitochondrial enzyme manganese superoxide dismutase (MnSOD), which is a superoxide anion scavenger. It is unknown whether genetic variability of the enzymes protecting against reactive oxygen species (ROS) can influence the development of respiratory failure in COPD patients. The aim of the study was to determine the correlation between polymorphism of MnSOD signal peptide and the occurrence of respiratory failure in the course of COPD. MATERIAL/METHODS: The study group consisted of 162 COPD patients (113 men and 49 women). The control group consisted of 63 subjects. Respiratory failure was diagnosed in 42 COPD patients. In all the examined subjects, the polymorphism resulting in alanine at residue 9 being replaced by valine and the expression of MnSOD in blood cells were determined. RESULTS: The Val/Val phenotype was demonstrated to occur in COPD patients more frequently than in the control group, as well as being associated with a lower expression level of MnSOD mRNA. Respiratory failure in the course of COPD also correlates with lower expression of MnSOD mRNA. CONCLUSIONS: The presence of valine at position 9 of the MnSOD signal peptide encoded by exon 2 is a risk factor for the occurrence of respiratory failure in the course of COPD in the Polish population.