Differences of glucocorticoid and beta2-adrenergic receptor mRNA expression in steroid-dependent asthma / 천식및알레르기

ABSTRACT

BACKGROUND: Steroid-dependency is one of Phenotypes of severe asthma. Because steroid-dependent asthmatics require long-term systemic steroids to control their symptoms. they have potentially increased risks to experience serious events caused by systemic steroids. But the pathophysiology of steroid-dependent asthma is poorly understood. Differences of glucocorticoid and beta2-aderenergic receptor expression may have some roles in the pathophysiology of steroid-dependent asthma. OBJECTIVE: The aim of this study was to evaluate the differences of mRNA expression of glucocorticoid receptor and beta2-adrenergic receptor between the steroid-dependent severe asthmatics and those with mild-to-moderate severity. METHODS: Thirty-nine asthmatic patients were enrolled, twenty with mild-to-moderate severity and nineteen with steroid-dependent severe asthma. Induced sputum was collected using 4% hypertonic saline nebulization and total RNA was extracted from the cells collected. Using RT-PCR, we asessed the amounts of glucocorticoid receptor and beta2-adrenergic receptor mRNA semiquantitatively from the extracted RNA. RESULTS: There were no significant differences in sex, age, smoking history, duration of asthma, positive rate of atopy, and percent predicted value of FEV1 between the two groups. The amount of glucocorticoid receptor mRNA expression was significantly lower in steroid-dependent asthmatic group than in mild-to-moderate severity group(p<0.05). There was no significant difference in amount of beta2-adrenoreceptor mRNA expression between the two groups. CONCLUSION: Decreased expression of glucocorticoid receptor mRNA may have some role in the pathophysiology of steroid-dependent asthma.