The effect of topical corticosteroid on basic fibroblast growth factor in nasal polyp tissue.

Background: The etiology of nasal polyposis and pathophysiological mechanisms of polyp formation is still poorly understood. Experimental models have suggested that nasal polyp growth requires extracellular matrix formation and is associated with fibroblast proliferation. Intranasal corticosteroids appear to be useful in reducing nasal polypoid lesions and the likelihood of polyp recurrence after surgery. Basic fibroblast growth factor (bFGF) is a potent angiogenesis factor and is mitogenic for a wide range of cell types. We investigated the alteration of bFGF levels in nasal polyp tissue after administration of topical corticosteroid.

Methods: Nasal polyp tissues were obtained from 36 patients with diffuse nasal polyposis before and after topical nasal steroid treatment. As a topical nasal steroid mometasone furoate was given for 4 weeks in a dosage of 200 microg/day. The bFGF levels were measured by competitive enzyme immunoassay method.

Results: The mean levels of tissue bFGF, before and after topical nasal steroid treatment, were 1485 +/- 826 ng/mg protein (range, 416-3434 ng/mg) and 1340 +/- 749 ng/mg protein (range, 330-3288 ng/mg), respectively. The levels of bFGF in nasal polyps were significantly lower than those before treatment after administration of topical nasal steroid (p = 0.011).

Conclusion: Administration of topical nasal steroid decreases bFGF levels of nasal polyp. It may be suggested that one of the effects in diminishing the size of nasal polyps is by decreasing the bFGF.