Propranolol Reduces the Development of Lesions and Rescues Barrier Function in Cerebral Cavernous Malformations

Background and Purpose: Cerebral cavernous malformations (CCM) present as mulberry-like malformations of the microvasculature of the central nervous system. Current medical treatment of CCM lesions is limited to surgical removal of the vascular malformations. It is, therefore, important to identify therapeutic drug treatments for patients with CCM. Propranolol has shown great benefit in the treatment of infantile hemangioma. In addition, patients with CCM who receive propranolol have demonstrated a reduction of their lesions. Our investigation set out to provide preclinical data to support propranolol as a therapeutic treatment. Methods: An inducible endothelial-specificCcm3 knockout murine model (CCM3iECKO ) was used, with assessment of lesion quantity and size following oral treatment with propranolol. Scanning and transmission electron microscopy were used to characterize the CCM3iECKO lesions and the effects of propranolol on the disease. Immunofluorescent imaging was used to investigate pericyte coverage in the propranolol-treated CCM3iECKO mice.Results: With propranolol treatment, the lesion quantity, size, and volume decreased in both the brain and retina in the CCM3iECKO model. Novel characteristics of the CCM3iECKO lesions were discovered using electron microscopy, including plasmalemmal pits and thickening of the endothelial-pericyte basal membrane. These characteristics were absent with propranolol treatment. Pericyte coverage of the CCM3iECKO lesions increased after propranolol treatment, and vascular leakage was reduced.Conclusions: This study supports the concept that propranolol can be used to reduce and stabilize vascular lesions and can, therefore, be suggested as a pharmaceutical treatment for CCM.