Decreased sodium-potassium and calcium adenosine triphosphatase activity in asthma: modulation by inhaled and oral corticosteroids

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.