Keywords

elastase, aneurysm, ultrasound, rat

Presentation Type

Event

Research Abstract

Abdominal aortic aneurysms (AAAs) are pathological dilations of the aorta which are associated with significant morbidity and mortality. The underlying mechanisms that cause this inflammatory disease are not fully understood and thus, are currently under investigation. In the hopes of preventing disease progression, rodent models that mimic the human condition have been developed to provide insight into the pathogenesis of AAAs. In this study, porcine pancreatic elastase (0.44 U; Sigma-Aldrich) was infused into the infrarenal aortas of male, Sprague Dawley rats to induce aneurysms. To perform the surgery, temporary ligatures were placed around proximal and distal sections of the abdominal aorta and a catheter was inserted into the vessel through an aortotomy slightly above the trifurcation to infuse elastase (30 minutes). Rats were imaged using a VisualSonics Vevo 2100 high-frequency ultrasound prior to and following surgery on days 3, 7, 14, 21, and 28. Of the 8 rats used in this study, 4 survived for 28 days and developed aneurysms. Pre-surgery abdominal aortas had a systolic diameter of 1.16 ± 0.19 mm and a diastolic diameter of 0.99 ± 0.17 mm. By day 14, AAAs had a systolic diameter of 2.32 ± 0.63 mm and a diastolic diameter of 2.25 ± 0.64 mm. Our efforts using this rat model will benefit future mesenchymal stem cell work aimed at preventing aneurysm formation by modulating the immune response. In conclusion, this study utilized high-frequency ultrasound to characterize an elastase-induced rat AAA model and will help increase our understanding of aneurysm pathogenesis.

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Development of Non-Invasive In Vivo Ultrasound Imaging Techniques for Elastase-Induced Experimental Abdominal Aortic Aneurysms

Abdominal aortic aneurysms (AAAs) are pathological dilations of the aorta which are associated with significant morbidity and mortality. The underlying mechanisms that cause this inflammatory disease are not fully understood and thus, are currently under investigation. In the hopes of preventing disease progression, rodent models that mimic the human condition have been developed to provide insight into the pathogenesis of AAAs. In this study, porcine pancreatic elastase (0.44 U; Sigma-Aldrich) was infused into the infrarenal aortas of male, Sprague Dawley rats to induce aneurysms. To perform the surgery, temporary ligatures were placed around proximal and distal sections of the abdominal aorta and a catheter was inserted into the vessel through an aortotomy slightly above the trifurcation to infuse elastase (30 minutes). Rats were imaged using a VisualSonics Vevo 2100 high-frequency ultrasound prior to and following surgery on days 3, 7, 14, 21, and 28. Of the 8 rats used in this study, 4 survived for 28 days and developed aneurysms. Pre-surgery abdominal aortas had a systolic diameter of 1.16 ± 0.19 mm and a diastolic diameter of 0.99 ± 0.17 mm. By day 14, AAAs had a systolic diameter of 2.32 ± 0.63 mm and a diastolic diameter of 2.25 ± 0.64 mm. Our efforts using this rat model will benefit future mesenchymal stem cell work aimed at preventing aneurysm formation by modulating the immune response. In conclusion, this study utilized high-frequency ultrasound to characterize an elastase-induced rat AAA model and will help increase our understanding of aneurysm pathogenesis.