Expression of β-adrenergic receptor subtypes in proliferative, involuted, and propranolol-responsive infantile hemangiomas

Abstract

IMPORTANCE: Propranolol hydrochloride has become the primary medical treatment for problematic infantile hemangioma; however, the expression of propranolol's target receptors during growth, involution, and treatment of hemangioma remains unclear. OBJECTIVE: To measure and compare the expression of β1-, β2-, and β3-adrenergic receptors (ADBR1, ADBR2, and ADBR3, respectively) in proliferative (n = 10), involuted (n = 11), and propranolol-responsive (n = 12) hemangioma tissue. DESIGN, SETTING, AND PARTICIPANTS: Infantile hemangioma specimens were harvested for molecular investigation.Messenger RNA (mRNA) expression ofthe ADBR1, ADBR2, and ADBR3 genes was detected by real-time polymerase chain reaction. Protein level expression was measured by Western blot and standardized with densitometry. A total of33 specimens were collected from patients in a tertiary pediatric hospital who underwent excision of problematic hemangiomas. This study was conducted from January 18, 2011, to September 24, 2013, and data analysis was performed from February 25, 2015, to June 25, 2016. RESULTS: Of the 33 patients included, 21 were female (64%). The mean (SD) patient age at the time of excision was 7 (2.5) months for the proliferative group lesions, 23.5 (10) months for the involuted group, and 16 (10) months for the propranolol group. The mean level of ADBR1 mRNA expression was significantly higher in proliferative hemangioma than in propranolol-responsive hemangioma (1.05 [0.56] vs 0.52 [0.36]; P =.01; 95% CI, 0.12-0.94). There was no difference in ADBR2 expression among the groups. Protein expression of ADBR3 was significantly higher in involuted (0.64 [0.12] vs 0.26 [0.04]; P