A Novel Renal Elastase-induced Saccular Aneurysm Model in Rats

Introduction: Even though existing large animal saccular aneurysm models have been widely used for preclinical safety and effectiveness evaluation of endovascular devices, they are not ideally suited to study the basic science of aneurysm healing mechanisms, mainly due to the limited availability of gene knock-out species. Murine species are readily genetically modifiable by established techniques, are relatively inexpensive, and have a shorter healing and breeding time compared to large animals. The use of rat models to study the efficacy of endovascular devices would thus permit the testing of numerous endovascular devices in a high throughput manner. We aim to create a murine aneurysm model to better understand the biological process of aneurysm healing after endovascular treatment.

Methods: We created a saccular aneurysm at the origin of the left renal artery by cannulating the left renal artery and applying intraluminal elastase, which is performed in tandem with extraluminal application of calcium chloride.

Results: Histopathologic studies of this model aneurysm demonstrated disconnected or absent internal elastic lamina, revealing aneurysmal changes in the arterial wall simulating pathologic findings from human aneurysm specimens.

Conclusion : This model, which now has many gene knockout combinations available, will allow us to investigate the biological mechanisms underlying both sustained aneurysm occlusion and recurrence after endovascular treatment in rats. Through a better understanding of aneurysm healing mechanisms, we believe this novel technique will promote the improvement of existing endovascular treatment modalities and facilitate the development of future generations of endovascular devices and techniques.