Molecular Targets for Intracranial Aneurysm Treatment

Intracranial aneurysms (IAs) are a common cerebrovascular pathology with deadly potential. Neurointerventionalists commonly treat IAs with endovascular coiling, minimizing procedural risk at the cost of an increased recurrence rate. New therapies for reducing the rate of coiled and uncoiled IA growth and rupture would help reduce the morbidity and mortality patients experience when IAs rupture. Hemodynamic shear stress drives IA formation through molecular mechanisms, generating damage-associated molecular proteins (DAMPs), which lead to inflammation and extracellular matrix remodeling. Nuclear factor κB (NF-κB) and interleukin-6 (IL-6) maintain an inflammatory environment in IA walls, generating immune-cell chemotactic proteins, such as monocyte chemoattractant protein-1 (MCP-1) and IL-8. These molecules play a complex role in IAs, being important for IA formation and IA healing. Vascular smooth muscle cells and infiltrated immune cells secrete matrix metalloproteinases (MMPs), which initiate extracellular matrix remodeling. Tissue inhibitors of matrix metalloproteinases (TIMPs) balance this remodeling. The increased MMP to TIMP ratio is characteristic of IA progression, making these molecules important targets for IA therapies. Endothelial dysfunction generates nitric oxide and other reactive oxygen species, which exacerbate inflammation and cell death in IA walls. A better understanding of molecular mechanisms underlying IA formation, progression, and rupture will allow researchers to develop molecular IA therapies.