The pigment epithelium-derived factor (PEDF): an important potential therapeutic agent for infantile hemangioma

In previous studies, the expression and the role of proangiogenic factors in infantile hemangiomas have been well studied. However, the role of angiogenic inhibitors has been revealed rarely. The expression of PEDF, as the strongest and safe endogenous inhibitor, is still unrecognized until the current study. In order to investigate the expression and significance of the pigment epithelium-derived factor (PEDF) in the proliferating and regressing phases of infantile hemangiomas, the expression of PEDF, VEGF, Ki-67, and CD34 protein in hemangioma tissues was examined with immunohistochemical polymer HRP method in 42 cases during the proliferative phase, 40 cases during the regressing phase, and 11 cases of non-involuting congenital hemangiomas (NICHs). Meanwhile, the mRNA expression of these factors was detected with quantitative realtime RT-PCR. We found the protein and mRNA expression of PEDF in regressing phase was significantly higher than those in proliferative phase and NICHs (P < 0.001), while the protein and mRNA expression of VEGF were much lower (P < 0.001). The microvessel density (MVD), Ki-67 changes, and the expression of PEDF and VEGF were found significantly correlated. These results indicated that the reduction of VEGF and increase in PEDF are causative to the evolution of infantile hemangioma. PEDF may play a key role in the spontaneous regression of infantile hemangioma and may become an important potential therapeutic agent for infantile hemangioma.