Background: Cerebral cavernous malformations (CCMs) are vascular malformations that frequently cause stroke. CCMs arise due to loss of function in one of the genes that encode the CCM complex, a negative regulator of MEKK3-KLF2/4 signaling in vascular endothelial cells. Gain-of-function mutations in PIK3CA (encoding the enzymatic subunit of the PI3K (phosphoinositide 3-kinase) pathway associated with cell growth) synergize with CCM gene loss-of-function to generate rapidly growing lesions.
Methods: We recently developed a model of CCM formation that closely reproduces key events in human CCM formation through inducible CCM loss-of-function and PIK3CA gain-of-function in mature mice. In the present study, we use this model to test the ability of rapamycin, a clinically approved inhibitor of the PI3K effector mTORC1, to treat rapidly growing CCMs.
Results: We show that both intraperitoneal and oral administration of rapamycin arrests CCM growth, reduces perilesional iron deposition, and improves vascular perfusion within CCMs.
Conclusions: Our findings further establish this adult CCM model as a valuable preclinical model and support clinical testing of rapamycin to treat rapidly growing human CCMs.
Keywords: humans; mice; mutation; perfusion; sirolimus; stroke.