A reproducible swine model of a surgically created saccular thoracic aortic aneurysm

Abstract

A reproducible swine thoracic aortic aneurysm (TAA) model is useful for investigating new therapeutic interventions. We report a surgical method for creating a reproducible swine saccular TAA model. We used eight female swine weighing 20-25 kg (LWD; ternary species). All procedures were performed under general anesthesia and involved left thoracotomy. Following aortic cross-clamping, the thoracic aorta was surgically dissected and the media and intima were resected, and the dissection plane was extended by spreading the outer layer for aneurysmal space. Subsequently, only the adventitial layer of the aorta was sutured. At 2 weeks after these procedures, angiography and computed tomography (CT) were performed. After follow-up imaging, the model animals were euthanized. Macroscopic, histological, and immunohistological examinations were performed. All model animals survived, and a saccular TAA was confirmed by follow-up imaging in all cases. The mean length of the shorter and the longer aortic diameter after the procedure were 14.01 ± 1.0 mm and 18.35 ±1.4 mm, respectively (p < 0.001). The rate of increase in the aortic diameter was 131.7 ±13.8 %, and the mean length of aneurysmal change at thoracic aorta was 22.4±1.9 mm. Histological examination revealed intimal tears and defects of elastic fibers in the media. Immunostaining revealed MMP-2 and MMP-9 expressions at the aneurysm site. We report our surgical method for creating a swine saccular TAA model. Our model animal may be useful to investigate new therapeutic interventions for aortic disease.

Animal Models, Pathogenesis, and Potential Treatment of Thoracic Aortic Aneurysm

“…The mean aortic clamping time is ~10 min. There is no serious complication associated with the procedure [121]. A saccular TAA is formed in all animals with a mean increase in aortic diameter of 132%.…”

“…In contrast, rodent models of TAAs are not suitable to be monitored using angiographic imaging. In addition, these porcine models could be used to assess the effectiveness of new therapeutic devices or interventions intended for clinical use in humans, in particular, to identify treatments for endoleaks after TEVAR [121,122] and new methods to minimize the damage caused by open surgical repair [123]. In contrast, rodent models are not suitable for testing TAA surgical repair procedures or devices due to the small size of the animals.…”

Animal Models and Pathogenesis of Thoracic Aortic Aneurysm

“…In contrast, rodent models of TAAs are not suitable to be monitored using angiographic imaging. In addition, these porcine models could be used to assess the effectiveness of new therapeutic devices or interventions intended for clinical use in humans, in particular, to identify treatments for endoleaks after TEVAR [121,122] and new methods to minimize the damages caused by open surgical repair [123]. In contrast, rodent models are not suitable for testing TAA surgical repair procedures or devices due to the small size of the animals.…”