Efficacy of bleomycin and sirolimus in inhibiting CD31(+) endothelial cell proliferation in noninvoluting congenital hemangiomas.

OBJECTIVE: Congenital hemangiomas are rare vascular anomalies that manifest at birth. Noninvoluting congenital hemangiomas present significant clinical challenges due to their persistence and associated complications. The mechanisms underlying congenital hemangiomas remain poorly understood, and current treatments have shown limited efficacy. This study aims to explore potential therapeutic strategies through the establishment of a stable cell model derived from noninvoluting congenital hemangiomas. METHODS: Primary cells were isolated from noninvoluting congenital hemangioma tissue obtained from five patients, and CD31-positive endothelial cells were cultured and characterized. A subcutaneous xenograft model was established in nude mice to investigate tumorigenicity and evaluate the effects of various drugs, including bleomycin and sirolimus. RESULTS: CD31-positive noninvoluting congenital hemangioma endothelial cells were successfully cultured and formed spheroids in vitro, demonstrating distinct morphological and immunohistochemical characteristics. When injected into nude mice, CD31-positive noninvoluting congenital hemangioma endothelial cells developed into tumors, whereas primary noninvoluting congenital hemangioma cells did not. Drug testing revealed that bleomycin and sirolimus effectively inhibited CD31-positive noninvoluting congenital hemangioma endothelial cells proliferation, with combination therapy showing significant tumor regression in vivo. CONCLUSION: The development of a stable cell model for noninvoluting congenital hemangiomas provides a valuable platform for understanding their pathogenesis and evaluating therapeutic options. The combination of bleomycin and sirolimus demonstrates promise as a novel treatment strategy, potentially improving outcomes for patients with noninvoluting congenital hemangiomas. Further studies are needed to explore the molecular mechanisms involved and to assess the efficacy across different congenital hemangioma subtypes.