Purpose Long-term occlusion of coiled aneurysms frequently fails, likely due to poor intrasaccular healing and inadequate endothelialization across the aneurysm neck. The purpose of this study was to determine if attachment of autologous MSC on platinum coils could improve healing response in an elastase-induced aneurysm model in rabbits.

Material and methods With institutional animal care and use committee approval, aneurysms were created in rabbits and embolized with control platinum coils (Axium, Medtronic) (n=6) or coils seeded ex vivo with autologous adipose-tissue mesenchymal stem cells (MSC) (n=7). Aneurysmal occlusion after embolization was evaluated at one month with angiography. Histological samples were analyzed with gross imaging and graded based on neck and dome healing on hematoxylin-eosin staining. Fibrosis was evaluated using a ratio of the total area presenting collagen. Endothelialization of the neck was quantitatively analyzed using CD31 immunohistochemistry. Chi-squared and student’s t-test were used to compare groups.

Results Healing score (11.5 versus 8.0, p=0.019), fibrosis ratio (10.3 versus 0.13, p=0.006.), and endothelialization (902,262 μm² versus 14,106 μm², p=0.04113) were significantly greater in the MSC group. The MSC group showed marked cellular proliferation and thrombus organization, with a continuous membrane bridging the neck of the aneurysm. Angiographic stable or progressive occlusion rate was significantly lower in the MSC group (0.00, 95% CI: 0.00–0.41) compared to controls (0.67, 95% CI: 0.22–0.96) (p=0.02).

Conclusions Autologous mesenchymal stem cells attached to platinum coils significantly improve histological healing as they result in improved neck endothelialization and collagen matrix formation within the aneurysm sac.

Disclosures A. Rouchaud: None. W. Brinjikji: None. D. Dai: None. Y. Ding: None. D. Kallmes: None. R. Kadirvel: None. R. Kadirvel: None.