Isolation, culture, and characterization of smooth muscle cells from human intracranial aneurysms

Smooth muscle cells (SMCs) play a critical role in the vascular wall and also participate in vascular repair mechanisms. Dysfunction of SMCs may also contribute to the formation of intracranial aneurysms (IAs) causing subarachnoid hemorrhage. Our aim was to investigate the possibility of using cultured SMCs as an in vitro model for the study of aneurysmal SMCs. IA tissue was obtained during microsurgical ligation of IAs. By using the explant method, cell cultures were established from the aneurysmal tissue. The phenotype of cultured cells from passage to passage was studied using immunoperoxidase staining and Western blotting. Eight cell lines could be established from 29 IA samples. Four lines showing most rigorous growth were investigated more thoroughly. Abundant expression of SMC markers, alpha-smooth muscle cell actin and calponin, as well as of prolyl-4-hydroxylases, a key enzyme family in the synthesis of collagens, was observed in all of them. Aneurysmal SMCs in culture maintained their phenotype and SMC characteristics through the early passages of growth. This is the first documented successful culture of SMCs from human IAs. An access to living human cells of aneurysmal origin gives us a new tool in our research of the formation, growth, and rupture of IAs.