Can the Infusion of Elastase in the Abdominal Aorta of the Yucatán Miniature Swine Consistently Produce Experimental Aneurysms?

Abstract

The intraluminal elastase perfusion model has been proved to be potentially effective in producing abdominal aortic aneurysm in rodents, but it produced unpredictable results in larger animals. The purpose of this study was to explore the potential ability of such a model to produce experimental aneurysm consistently in the Yucatán miniature swine. Six Yucatán miniature swine received infusion with porcine elastase into an isolated segment of the infrarenal aorta. The excised arterial segments were examined macroscopically to assess the luminal surface characteristics and histologically to describe the different pathologic injuries induced by the elastase treatment on the intima, media, and adventitia of the arterial wall. Histologic examination revealed that the elastic network of the media was destroyed. In the first week after perfusion, altered smooth muscle cells were located in the intima and innermost layer of the media in juxtaposition with the occlusive thrombus. Infiltration of inflammatory cells was observed in these regions of elastic network and smooth muscle cell alterations. In the arterial segments of swine sustained for 3 weeks, a reduction of smooth muscle cells was noted in some areas. An important number of necrotic lesions was observed, and they were associated with the development of calcium deposits. Significant intimal hyperplasic reaction was identified at day 19 and again at day 21. However, no aneurysmal development was observed. This study constituted the first experiment with infusion of porcine elastase in the Yucatán miniature swine infrarenal aorta. The present experimental protocol induced important elastic network and smooth muscle cell alterations leading to severe necrotic lesions associated with calcium deposition, but it produced no aneurysmal dilatation. This model requires further testing to obtain a more complete degradation of the elastic network in both the media and adventitia and more significant collagenolysis without early thrombotic events.

Reproducible Porcine Model of Thoracic Aortic Aneurysm

“…Conversely, several large animal models (rabbit, swine) have previously been developed for the study of abdominal aortic aneurysms (AAA). 26–29 While there have been variable results in regard to the amount of aortic dilatation achieved, porcine models of AAA utilizing pancreatic elastase have demonstrated collagen and elastic degradation with an associated increase in MMP production. 26, 28, 29 In a rabbit model of AAA, adventitial application of calcium chloride along with a high cholesterol diet and the induction of adventitial inflammation caused a doubling of the aortic diameter in three weeks.…”

Shortened Elastase Infusion Time in the Elastase-Induced Rat Aneurysm Model

“…It was first thought that the high mortality was related to the aortic length infused. Marinov et al [12] reported that four of the six Yucatan miniature swines which underwent elastase infusion of the abdominal aorta were sacrificed within 7 days because of severe clinical deterioration and aortic occlusion by thrombus. Therefore, we compared the mortality rate of rats in which a 0.5-cm segment of aorta was perfused with the mortality rate of rats in which a 1.0-cm segment of aorta was perfused.…”

The effect of proteolytic treatment on plastic deformation of porcine aortic tissue

“…Boudghene et al (1993) reported successfully inducing a small dilation in dog abdominal aorta in vivo using the elastase perfusion method for the purpose of testing endovascular grafts. Similar attempts in other animals have not been successful (Marinov et al, 1997). The ability to create reliable large animal models of AAA remains elusive.…”