Expression of endoglin (CD105) and endothelial nitric oxide synthase in head and neck arteriovenous malformations.

IMPORTANCE Endoglin (CD105) and endothelial nitric oxide synthase (eNOS) assist in regulating vascular development. Variation in expression of these factors is linked to errors in vascular growth and remodeling in invasive lesions. OBJECTIVE To clarify the role of endoglin and eNOS in the growth of extracranial head and neck arteriovenous malformations (AVMs), an invasive and high-flow vascular anomaly. DESIGN AND SETTING Immunohistochemistry and Western blot study at an academic research center. SPECIMENS Frozen and formalin-fixed paraffin-processed human AVMs (n = 14) were examined for expression of CD105 and eNOS. Expression in infantile hemangiomas (n = 9) and in normal skin with subcutaneous tissue (n = 9) was used for comparison. MAIN OUTCOME MEASURES Quantitative assessment and localization of CD105 and eNOS protein expression were performed on each specimen by immunohistochemistry and Western blot analysis. Protein expression levels were compared with β-actin level and were semiquantitatively assessed. RESULTS Abundant CD105 protein was found in AVMs but was not present in infantile hemangiomas or normal skin with subcutaneous tissue. Expression of eNOS protein in AVMs and infantile hemangiomas was similar (P = .20) and was significantly greater than that in normal skin with subcutaneous tissue (P < .001 and P = .008, respectively). Immunohistochemistry demonstrated that CD105 and eNOS are predominantly located in AVM vascular endothelial cells. CONCLUSIONS AND RELEVANCE CD105 and eNOS are present and significantly expressed in head and neck AVMs. Expression of CD105 and eNOS may have an important role in the angiogenesis and vascular remodeling of AVMs. CD105 can be used as a specific marker for AVM endothelial cells.