β 1 -Adrenoceptor mRNA level reveals distinctions between infantile hemangioma and vascular malformations

Abstract

Background:Infantile hemangioma (IH) is the most frequent vascular tumor of early childhood. Recently, propranolol, a nonselective β 1 - and β 2 -Adrenoceptor inhibitor, was introduced into the therapy of severe proliferating IH with excellent results. However, the underlying mechanism of action of propranolol is still unclear.Methods:We performed immunohistochemistry for cluster of differentiation 31 (CD31), D2-40, glucose transporter-1 (GLUT-1), and Ki67 in order to characterize 21 vascular anomalies (nine IH, seven venous malformations (VMs), and five lymphatic malformations (LMs)). Furthermore, we analyzed the expression of β 1 -, β 2 -, and β 3 -Adrenoceptor mRNA in these specimens as well as in hemangioma-derived stem cells by quantitative real-time PCR (qPCR).Results:We show that the expression of β 1 -Adrenoceptor mRNA is 10.7-fold higher in IH independent of the proliferative or regressive phase as well as 2.5-fold higher in hemangioma-derived stem cells as compared with β 2 -Adrenoceptor mRNA. In LM, the expression of β 2 -Adrenoceptor mRNA was ninefold higher than that of β 1 -Adrenoceptor mRNA. VM showed low expression levels of all β-Adrenoceptor mRNAs, and β 3 -Adrenoceptor mRNA was hardly detectable in any specimens examined.Conclusion: These results provide the first evidence of distinctions between IH and vascular malformations with regard to β-Adrenoceptor subtype mRNA levels. Copyright © 2013 International Pediatric Research Foundation, Inc.