Synergistic effects of fluticasone propionate and salmeterol on in vitro T-cell activation and apoptosis in asthma.
BACKGROUND
In asthma T cells are characterized by an increased activation state and by reduced apoptosis.


OBJECTIVE
Because the clinical efficacy of inhaled corticosteroids combined with long-acting beta 2 -agonists has been widely demonstrated in asthma, we studied, in vitro, the effect of fluticasone propionate (FP) and salmeterol alone and in combination on the activation and apoptosis of peripheral blood T cells (PBTs), on the expression of phosphorylated nuclear factor kappaB inhibitor (IkappaBalpha), and on the nuclear translocation of glucocorticoid receptor (GR) in PBTs from asthmatic subjects.


METHODS
Apoptosis was evaluated on the basis of annexin V binding, whereas the expression of caspases 8 and 3 and phosphorylated IkappaBalpha, as well as the nuclear translocation of the GR, were evaluated by means of Western blot analysis.


RESULTS
FP alone increases and salmeterol alone does not affect T-cell apoptosis. The combination of FP and salmeterol significantly increases PBT apoptosis in comparison with FP alone. FP at the lower concentration, when combined with salmeterol, is equivalent to FP at the higher concentration in inducing PBT apoptosis. The synergy in the induction of cell apoptosis is associated with more efficient activation of caspases 8 and 3. FP plus salmeterol is also able to synergistically reduce the expression of phosphorylated IkappaBalpha, thus limiting nuclear factor kappaB activation. The synergy was related to an increased nuclear translocation of the GR.


CONCLUSIONS
This study shows that the combination of FP and salmeterol is able to control PBT activation in asthmatic patients more efficiently than FP alone and with a lower concentration of steroids.
Pace
Elisabetta
E
Istituto di Biomedicina e Immunologia Molecolare, Consiglio Nazionale delle Richerche, Via Ugo La Malfa 153, 90146 Palermo, Italy. pace@ibim.cnr.it
Gagliardo
Rosalia
R
Melis
Mario
M
La Grutta
Stefania
S
Ferraro
Maria
M
Siena
Liboria
L
Bonsignore
Giovanni
G
Gjomarkaj
Mark
M
Bousquet
Jean
J
Vignola
Antonio M
AM
D021581:Active Transport, Cell Nucleus; D000293:Adolescent; D000420:Albuterol / Q000031:analogs & derivatives* / Q000494:pharmacology*; D000730:Androstadienes / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D001249:Asthma / Q000188:drug therapy* / Q000276:immunology; D020169:Caspases / Q000502:physiology; D002648:Child; D004357:Drug Synergism; D000068298:Fluticasone; D006801:Humans; D020672:I-kappa B Proteins / Q000378:metabolism; D008213:Lymphocyte Activation / Q000187:drug effects*; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000037:antagonists & inhibitors; D010766:Phosphorylation; D011965:Receptors, Glucocorticoid / Q000378:metabolism; D000068299:Salmeterol Xinafoate; D013601:T-Lymphocytes / Q000187:drug effects* / Q000276:immunology
D000730:Androstadienes; D020672:I-kappa B Proteins; D016328:NF-kappa B; C000606204:NFKBIA protein, human; D011965:Receptors, Glucocorticoid; D000072000:NF-KappaB Inhibitor alpha; D000068299:Salmeterol Xinafoate; D000068298:Fluticasone; D020169:Caspases; D000420:Albuterol