A pilot study of estrogen's effects on bronchial myocyte adhesion moleculeexpression

We examined the effects of estrogen on tumor necrosis factor alpha (TNF-alp ha)induced expression of intracellular adhesion molecule (ICAM-1) and vascu lar adhesion molecule (VCAM-1) in cultured human bronchial smooth muscle ce lls (BSMC). Experiments were performed in triplicate in T-75 tissue culture flasks containing normal human BSMC. Four experiments were carried out: un treated BSMC cells (control); TNF-alpha 1000 U/ml stimulation of BSMC; fors kolin 5 mu M before TNF-alpha stimulation of BSMC; and estradiol 30 mu M be fore TNF-alpha stimulation of BSMC. Cyclic adenosine monophosphate was meas ured by a commercially available radioimmunoassay kit. Cell expression of I CAM-1 and VCAM-1 was quantified by flow cytometry. Incubation of cells with TNF-alpha 1000 U/ml for 24 hours elicited a 27-fold increase in basal expr ession of ICAM-1 and a 2-fold increase in VCAM-1 (p>0.05). Incubation of BS MC with forskolin 5 mu M, for 1 hour before TNF-alpha, decreased TNF-alpha- induced expression of ICAM-1 by 62% and VCAM-1 slightly by 17%. The BSMC in cubated with estradiol 30 mu M, 1 hour before TNF-alpha, decreased TNF-alph a-induced expression of ICAM-1 by 21%; VCAM-1 remained unchanged (p>0.05). We found a trend toward inhibition of TNF-alpha-stimulated ICAM-1 expressio n in cultured BSMC with pretreatment with estradiol. However, due to large variability within the cell culture model, statistical significance was not reached.