Inhibition of collagen expression by azelastine hydrochloride in cultured skin fibroblasts from normal individuals and scleroderma patients.

The effects of azelastine hydrochloride on cell proliferation and collagen synthesis in cultured human skin fibroblasts were studied. Azelastine inhibited cell proliferation during proliferating cell phases. Azelastine was found to inhibit collagen synthesis without altering cell proliferation during quiescent phases. It did not alter the ratio of type I to III collagen synthesis. Northern blot analysis of collagen chain mRNAs revealed that the levels of alpha1 (I), alpha1 (III) and alpha1 (VI) mRNAs were reduced by azelastine treatment, whereas the level of alpha2 (VI), alpha3 (VI) mRNAs were not significantly changed. These results suggest that azelastine modulates collagen synthesis at a pretranslational level. Azelastine inhibited collagen synthesis in fibroblasts from scleroderma patients to the same extent as in normal skin fibroblasts. This drug may be useful in the treatment of fibrotic diseases.