Serum trace element levels in patients with bronchial asthma

SUMMARY Serum trace element levels in patients with bronchial asthma Dr. Nevin Uzuner Free radicals have been proposed to be responsible from the pathogenesis of many diseases because of their harmful effects on the cells and tissues. One of the most impartant of these diseases is bronchial asthma. There are some defence mechanisms in the organism to avoid the harmful effects of free radicals. These defense mechanisms (antioxidant) act through prevention of free radical formation, reduction of their activities or destruction of these radicals. The enzymes responsible from antioxidant defense have trace elements like selenium, zinc and copper within their structure. Decreased levels of these elements lead to a reduction in antioxidant activity. Thus, the fine balance between the oxidants responsible from the pathogenesis of asthma and antioxidant defence mechanisms is compromised. As a result, elevation of free radical levels in the airways of asthmatic patients leads to smooth muscle contraction, increased mucus secretion and most importantly hyperreactivity. This study was conducted to determine serum levels of some trace elements (Se, Zn, Cu) and of an intracellular cation (Mg) in asthmatic patients during acute attacks, after inhaled corticosteroid therapy and during asymptomatic periods in order to evaluate the relation of these elements to different clinical phases of asthma. The study and control cases included 40 asthmatic children being followed up in Department of Pediatric Allergy Dokuz Eylül Universty Medical Faculty, and 19 children presenting with enuresis nocturna and having no personal or family history of allergy. Patients presenting with acute asthmatic attacks (group 1) were evaluated before the treatment (pretreatment) and after three months of Fluticasone Propionate (400 ug daily) therapy (posttreatment). The other study group included asthmatic patients who were asymptomatic (group 2). Control group was the children presenting with enuresis with no history of allergic disease (group 3). The mean ages of the children were 8.93 ± 2.08, 8.53 ± 1.79, and 9.24 ± 2.18 years in the first, second and third groups respectively, and they were not different statistically with respect to age (p>0.05). The mean weights of the children were 29.23 ± 8.11 kg in group 1, 28.08 ± 8.07 kg in group 2 and 30.76 + 9.65 kg in group 3 and there was no significant difference between the groups (p>0.05). All three groups were also not 8different significantly with respect to heights of the children (131.36 ± 10.59 cm in group 1, 128.94 ± 13.42 cm in group 2 and 134.82 ± 13.31 cm in group 3, p>0.05). No significant sex difference was present among the groups [ 13 (59 %), 18 (55.6 %), and 8 (44.4 %) were male in the groups 1,2 and 3 respectively, p>0.05]. Serum selenium, zinc, copper and magnesium levels were measured in all cases. In addition, pulmonary function tests were performed and FVC and FEV1 were determined in all the children. Serum selenium, zinc and magnesium levels during acute attacks and after inhaled corticosteroid trerapy were significantly different in group 1, being lower during acute attacks (p<0.05). However, pre and posttreatment serum copper levels did not differ (p>0.05). FVC and FEV1 were also statistically different in the pre and posttreatment periods (p<0.05). Although serum selenium, zinc and magnesium levels were significantly lower when group 1 (pretreatment) was compared with groups 2 and 3 (p<0.05), serum copper levels did not differ between the groups (p>0.05). FVC and FEV1 were also significantly different between the three groups (p<0.05). When group 1 (posttreatment) was compared with groups 2 and 3 with respect to the previous parameters, only serum selenium levels were statistically different between the three groups (p<0.05). Overall, serum selenium, zinc and magnesium levels were reduced during acute asthma attacks, while they were normal after inhaled corticosteroid therapy which has antiinflammatory and antioxidant effects. In conclusion, these results show that,there is an oxidant stress in bronchial asthma, and antioxidant capacity decreases in parallel to a decrease in serum selenium, zinc and magnesium levels. This leads to a further increase in oxidant stress, and as a result, inflammation and hyperreactivity in the airways becomes more evident. We speculate that, dietary deficiencies in selenium, zinc and magnesium should be avoided with proper supplementations in the management of airway inflammation due to free oxygen radicals in asthmatic patients to increase the effect of antioxidant defense system. Key words:Asthma, free oxygen radicals, antioxidant defense mechanism, trace elements.