Mesenchymal stem cells and endothelial progenitor cells accelerate intra-aneurysmal tissue organization after treatment with SDF-1α-coated coils.

Recurrences of aneurysms remain the major drawback of detachable coils for the endovascular treatment of intracranial aneurysms. The aim of the present study is to develop new modified coils, coating the surface of platinum coils with silk fibroin (SF) consisting of stromal cell-derived factor-1α (SDF-1α), and evaluate its acceleration of organization of cavities and reduction of lumen size in a rat aneurysm model. The morphological characteristics of SDF-1α-coated coils were examined using scanning electron microscopy (SEM). Fifty experimental aneurysms were created and randomly divided into five groups: three groups were embolized with SDF-1α-coated coils (8 mm) and two of these groups need transplantation of mesenchymal stem cells (MSCs) or endothelial progenitor cells (EPCs); one group was embolized with bare coils (8 mm) and another group severed as control. After coil implantation for 14 or 28 days, the coils were harvested and histological analysis was performed. SEM photographs showed that SF/SDF-1α-coated coils have uniform size and a thin film compared with bare coils. In the group treated with SDF-1α-coated coils, tissue organization was accelerated and the proliferation of α-smooth muscle actin positive cells was promoted in the aneurysmal sac. Compared with unmodified coils, on day 28, tissue organization was significantly greater in the group treated with SDF-1α-coated coils and MSC or EPC transplantation. These results suggest that SDF-1α-coated coils with MSC or EPC transplantation may be beneficial in the aneurysm healing and endothelialization at the orifice of embolized aneurysm.