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Abstract
Background and Purpose Unruptured aneurysms pose a significant risk of rupture and remain poorly understood despite decades of preclinical and clinical research. Our study focused on understanding the patterns of endothelial cell distribution in different spatial locations within the aneurysm in a rabbit model.
Methods Aneurysms were created in 20 rabbit subjects using the elastase-induced model technique. Aneurysm tissues were harvested at 2 weeks (n=5), 4 weeks (n=4), 8 weeks (n=5) and 12 weeks (n=6) following aneurysm creation. Aneurysm tissues were processed and en face whole tissuemount CD31 staining of aneurysm tissue for endothelial cells was performed. A semi-quantitative scoring of the aneurysm was performed and categorized into 5 divisions based on the endothelial coverage of the vessel wall (Score5-highly confluent, 0- no endothelial cells) at the proximal, middle and distal portions of the aneurysm dome. Scoring was done by a single person who was blinded to the time point of sacrifice.
Results Our study revealed a endothelialized wall in all the regions the aneurysm with median score of 1.8 (proximal dome and middle dome) and 1.6 (distal dome) at 2 weeks. However, the endothelialization reduced at 4 weeks (median=0) in all 3 regions. In the 8 weeks group reendothelialization was prominent in the proximal region (median=1.6) in comparison to middle and distal regions (median=0). In 12 weeks group reendothelialization was prominent in proximal (median=1.5), middle (median=2.4) and distal (median=1.1) regions of aneurysm wall.
Conclusion The wall of the elastase-induced rabbit aneurysm can be categorized into 5 types based on the degree of endothelialization of aneurysm. Based on the CD31 distribution within the aneurysm, the pattern of deendothelialization and reendothelialization over time can be correlated.
Disclosures P. Kolumam Parameswaran: None. D. Dai: None. Y. Ding: None. R. Kadirvel: None. D. Kallmes: 1; C; NIH : NS08825602.
