TNP-470 (a fungus-derived inhibitor of angiogenesis) reduces proliferation of cultured fibroblasts isolated from primary pterygia: a possible drug therapy for pterygia

Purpose. To study drug therapy for pterygium, especially the effect of a fumagillin analog, TNP-470, a potent anti-angiogenic compound, on the growth of cultured fibroblasts obtained from primary pterygia and normal human conjunctiva. Methods. Cultured pterygium fibroblasts (PF) were exposed to different concentrations of TNP-470 every other day for 7 days (Treatment A) and to a single dose before 4 days of culture (Treatment B). Human normal conjunctival fibroblasts (HCF) were treated with TNP-470 every other day for 7 days. The cells were observed daily by phase contrast microscopy. Cell proliferation was assessed by counting cells with a hemocytometer. Trypan blue uptake was used to determine cell viability at harvest. Results. TNP-470 induced a significant inhibition of PF and HCF proliferation in a dose-dependent manner (P < .0001). At the lowest dose of TNP-470 (100 pg/ml), the cumulative inhibitory effect of TNP-470 was more potent than the sustained inhibitory effect observed by treatment B in one high dose. Nevertheless, the cytotoxic effect was dose-dependent and more marked after treatment A than after treatment B. After washing out of the drug, partial reversibility was observed at doses lower than 5 mg/ml with a significant increase of viability. HCF were less sensitive to TNP-470 and doses less than 5 mg/ml were not cytotoxic. Conclusions. TNP-470 appears to have a marked inhibitory effect on PF proliferation, and it may be of considerable value in the prevention of pterygium growth and recurrence.