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Updated: Nov 10, 2025
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Creation of Two Saccular Elastase-Digested Aneurysms with Different Hemodynamics in One Rabbit
Published on: April 15, 2021
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Adaptive Remodeling in the Elastase-induced Rabbit Aneurysms
C Sang1, D F Kallmes2, R Kadirvel2
1Department of Mechanical Engineering and Materials Science, University of Pittsburgh, 3700 O'Hara Street, Pittsburgh, PA 15261.
Experimental Mechanics
|April 5, 2021
Summary
Brain aneurysm walls rapidly adapt to stress through collagen remodeling, forming a new layer to maintain structural integrity. This adaptive mechanism ensures stability until slower medial reorganization occurs, offering insights for new therapies.
Area of Science:
- Biomedical Engineering
- Vascular Biology
- Materials Science
Background:
- Brain aneurysm rupture carries high fatality and morbidity.
- Aneurysm walls can adapt via collagen matrix remodeling, maintaining stability despite geometric changes.
Purpose of the Study:
- To investigate adaptive remodeling in an elastase-induced rabbit aneurysm model.
- To characterize the structural changes in aneurysm walls over time.
Main Methods:
- Saccular aneurysms were created in 22 rabbits.
- Aneurysm wall remodeling was assessed at 2, 4, 8, and 12 weeks post-creation.
- A constitutive model was developed incorporating observed remodeling.
Main Results:
- Intramural stress ratio doubled post-aneurysm creation, triggering remodeling.
- A new multi-directional collagen layer formed between 2-4 weeks (50.6 ± 14.3 μm thick).
- Collagen fibers in the new layer were multi-directional and less tortuous than medial and adventitial fibers.
Conclusions:
- A novel mechanism of rapid aneurysm wall adaptation to stress was identified.
- This rapid adaptation ensures structural integrity until slower medial reorganization.
- The rabbit model is suitable for evaluating therapies to enhance aneurysm stability.
