Selenium supplementation in intrinsic asthma.

The accumulated data indicate that asthma is associated with reduced circulatory selenium (Se) status and lowered activity of the Se-dependent enzyme glutathione peroxidase (GSH-Px), which may have etiological implications, considering the important role of GSH-Px in the cellular elimination of hydroperoxides. The aim of the present double-blind study was to investigate whether Se supplementation in asthmatic patients may increase GSH-Px activity and possibly bring about clinical improvement. Twenty-four patients suffering from intrinsic asthma were selected and randomized into two groups, and after a preintervention period of 4 weeks, one group received a daily supplement of 100 micrograms sodium selenite for 14 weeks, whereas the other group received placebo. In the Se-supplemented group there were significant increases in serum Se and platelet GSH-Px activity after intervention, accompanied by a significant reduction in the irreversible platelet aggregation induced by 5 mumol/l ADP, while no significant changes in these parameters could be observed in the placebo group. Further, there was a significant clinical improvement in the Se-supplemented group, as compared with the placebo group, with regard to the assembled clinical evaluation made of each patient. This improvement could, however, not be validated by significant changes in the separate clinical parameters of lung function and airway hyperresponsiveness. The results are discussed in view of the role of GSH-Px in the cellular enzymatic oxidant defense system and as a modulator of arachidonic acid metabolism.

Lowered platelet glutathione peroxidase activity in patients with intrinsic asthma.

Platelet glutathione peroxidase (GSH-Px) activity and serum selenium (Se) levels were determined in 20 patients with intrinsic asthma. Nine of the patients had NSAID-intolerance. The mean value of GSH-Px activity in the patients was 47.0 +/- 7.1 U/10(11) platelets, which is significantly lower than that of 56.4 +/- 12 U/10(11) platelets in the controls (P less than 0.01). There was also a tendency towards lowered Se levels in the patients compared with controls. The results are discussed in view of the protective role of GSH-Px against oxidative stress and the tentative regulatory function of GSH-Px in arachidonic acid metabolism.

Lowered glutathione-peroxidase activity in asthmatic patients with food and aspirin intolerance.

In analogy with findings from animal experiments, people with low glutathione-peroxidase (GSH-Px) activity could be expected to have altered sensitivities to effects of drugs, chemicals and possibly food. We have investigated GSH-Px activity in 12 patients with intrinsic asthma and food and aspirin intolerance. Ten of the 12 patients had very low or low GSH-Px activity and the frequency of low GSH-Px activity in this group was statistically significant (P less than 0.001) compared with the control material of age- and sex-matched healthy individuals. Our finding of lowered GSH-Px activity in patients with aspirin intolerance may indicate the involvement of hitherto unknown mechanisms in the pathogenesis of asthmatic disorders.