Animal models for abdominal aortic aneurysms: Where we are and where we need to go

The mortality rate of patients with abdominal aortic aneurysm (AAA) after rupture is extremely high, and this disease has become an important disease endangering the health of the Chinese population. Methods used to model AAA include intraluminal pressurized elastase infusion, chronic infusion of angiotensin II (Ang II) via an osmotic pump, periarterial application of calcium chloride, vascular grafting, and gene modification. AAA models induced by elastase and Ang II are the two most widely used animal models. In the elastase-induced model, because intraluminal infusion is transient, with the cessation of initial stimulation, the aneurysm lesion tends to be stable and rarely ruptures. The model induced by Ang II infusion often presents with a typical aortic dissection with a false lumen, whereas clinical AAA patients do not necessarily have dissection. Currently, the treatment of AAA in clinical practice remains endovascular, and there is a lack of pharmacological therapy, which is also related to the fact that the pathogenic mechanism has not been fully elucidated. Smoking, old age, male sex, and hypertension are the main risk factors for AAA, but these risk factors have not been fully investigated in the current modeling methods, which may affect the clinical translational application of research results based on animal models. Therefore, this article reviews the most commonly used AAA modeling methods, comments on their applications and limitations, and provides a perspective on the development of novel animal models.