[Show abstract][Hide abstract] ABSTRACT: The present study was carried out to determine the intracellular free calcium concentration ([Ca(2+)](i)) and the activity of its regulatory enzymes (Na(+),K(+)-ATPase and Ca(2+)-ATPase) in leucocytes. Levels of plasma lysophosphatidylcholine (LPC) were also measured. Then the relationship between these parameters and the clinical severity of asthma and bronchial reactivity was studied. Patients with asthma were divided into three groups: acute asthma (subjects in acute exacerbation), uncontrolled asthma (subjects currently symptomatic) and stable asthma (subjects currently asymptomatic). A group of normal subjects was also studied. Spirometry, specific airway conductance and bronchial reactivity measurements were carried out. The following biochemical parameters were studied in venous blood: leucocyte [Ca(2+)](i), Na(+), K(+)-ATPase and Ca(2+)-ATPase activities, and plasma LPC. Leucocyte [Ca(2+)](i) was increased and the activities of Na(+),K(+)-ATPase and Ca(2+)-ATPase were decreased in patients with asthma. Plasma levels of LPC were also increased. These changes were observed to be greatest among asthmatics in acute exacerbation of asthma, and lesser in magnitude in patients with less severe asthma. The activities of both ATPases were found to have a significant positive correlation, and [Ca(2+)](i) and the levels of plasma LPC a significant negative correlation, with predicted forced expiratory volume in 1 s (FEV(1)). No significant correlation was observed between the biochemical parameters and bronchial reactivity. It is concluded that intracellular calcium homoeostasis is abnormal in asthma; specifically, the activities of Na(+),K(+)-ATPase and Ca(2+)-ATPase are decreased. These abnormalities may modulate the clinical severity of asthma.
[Show abstract][Hide abstract] ABSTRACT: The activation of both the inflammation-producing cells and the airway smooth muscle in asthma is believed to be a phenomenon dependent on the intracellular calcium. The activity of Na+ K+ ATPase and Ca2+ ATPase, enzymes responsible for regulating the intracellular calcium concentrations has been reported to be decreased in asthma. An increase in plasma lysophosphatidylcholine (LPC), which is known to be a pro-inflammatory compound and has an inhibitory effect on the two ATPases has also been reported. Corticosteroids are potent antiinflammatory drugs very effective in the treatment of asthma. The effect of long-term (12 weeks) treatment with inhaled beclomethasone dipropionate (BDP) and short-term (1 week) treatment with oral prednisolone on the activity of the two ATPases and intracellular calcium in leukocytes and plasma LPC levels was investigated. Both the treatments resulted in an improvement in lung function accompanied by an increase in the activities of the ATPases and a decrease in the intracellular calcium and LPC levels. It was concluded that increase in the activities of Na+ K+ ATPase and Ca2+ ATPase and a consequent lowering of intracellular calcium, and a lowering of plasma LPC may underlie the beneficial effect of corticosteroids in asthma.
No preview · Article · Jan 1999 · The Indian journal of chest diseases & allied sciences