Sildenafil suppresses the proliferation and enhances the apoptosis of hemangioma endothelial cells.

Treatment of infantile hemangiomas (IH) with propranolol was first reported in 2008. Regressions of lymphatic malformations combined with pulmonary hypertension was first reported in 2012 after three children received treatment with oral sildenafil, which serves as an antagonist of phosphodiesterase isoform-5 (PDE-5). A marked expression of endothelial cells in the cytoplasm of IH tissues was obtained in our previous study. Therefore, the present study hypothesized that the antagonist of PDE-5, sildenafil, may lead to the regression of hemangiomas. To assess this hypothesis, the proliferation and apoptosis of specimen-derived hemangioma endothelial cells (HemECs) was determined by an MTT assay and flow cytometry, respectively, following treatment with sildenafil. The potential mechanisms underlying the mRNA and protein expression levels of inhibitor of differentiation 1 (Id-1) were determined by reverse transcription-quantitative polymerase chain reaction and western blotting. The results demonstrated that 5 µM sildenafil suppressed the proliferation of HemECs and significantly enhanced the rate of apoptosis after 24 h. Additionally, the mRNA and protein expression levels of Id-1 were downregulated following treatment with sildenafil. Therefore, the present study concluded that PDE-5 may be a potential therapeutic target for hemangiomas and Id-1 may serve a vital role in the associated signaling transduction pathways.