β-Adrenergic receptor expression in vascular tumors

Area of Science:

• Vascular Biology
• Pharmacology
• Dermatology

Background:

• Propranolol is an effective therapy for infantile hemangiomas, potentially acting via nitric oxide, VEGF, and apoptosis.
• Previous work identified beta-2 adrenergic receptors (B2-AR) in a responsive infantile hemangioma case.
• The expression of beta-adrenergic receptors (βARs) in diverse vascular lesions remains largely unexplored.

Purpose of the Study:

• To investigate the expression of β2-AR, phosphorylated β2-AR (B2-ARP), and β3-AR (B3-AR) across a spectrum of vascular lesions.
• To determine if βAR expression patterns correlate with potential responsiveness to propranolol or other beta-blockade therapies.

Main Methods:

• Utilized a tissue microarray with 141 vascular lesions, including infantile hemangiomas, angiosarcomas, hemangiomas, hemangioendotheliomas, and vascular malformations.
• Performed immunohistochemical staining for B2-AR, B2-ARP, and B3-AR on the tissue microarray.
• Scored endothelial cell expression intensity as negative, weak positive, or strong positive.

Main Results:

• Infantile hemangiomas (all phases) showed strong expression of B2-AR, B2-ARP, and B3-AR, with a minor exception for B2-ARP in the proliferative phase.
• Strong expression of all three receptors was observed in many hemangiomas, hemangioendotheliomas, and vascular malformations.
• Absent to weak expression of all three receptors was noted in glomus tumors, hobnail hemangioendotheliomas, pyogenic granulomas, and reactive vascular proliferations.

Conclusions:

• This is the first study to report βAR expression in a variety of vascular lesions.
• The widespread expression of βARs suggests that beta-blockade might offer therapeutic potential for a broader range of vascular lesions beyond infantile hemangiomas.
• Further research is warranted to confirm the functional implications of βAR expression and explore therapeutic avenues, especially for lesions with limited treatment options.