In vitro histomechanical effects of enzymatic degradation in carotid arteries during inflation tests with pulsatile loading

Abstract

In this paper, the objective is to assess the histomechanical effects of collagen proteolysis in arteries under loading conditions reproducing in vivo environment. Thirteen segments of common porcine carotid arteries (8 proximal and 5 distal) were immersed in a bath of bacterial collagenase and tested with a pulsatile tension/inflation machine. Diameter, pressure and axial load were monitored throughout the tests and used to derive the stressstretch curves and to determine the secant circumferential stiffness. Results were analyzed separately for proximal and distal segments, before and after 1, 2 and 3 hours of enzymatic degradation. A histological analysis was performed to relate the arterial microstructure to its mechanical behavior under collagen proteolysis. Control (before enzymatic degradation) and treated populations (after 1, 2 or 3 hours of enzymatic degradation) were found statistically incomparable, and histology confirmed the alteration of the fibrous structure of collagen bundles induced by the collagenase treatment. A decrease of the secant circumferential stiffness of the arterial wall was noticed mostly at the beginning of the treatment, and was less pronounced after 1 hour. These results constitute an important set of enzymatically damaged arteries that can be used to validate biomechanical computational models correlating structure and properties of blood vessels.

Building Valveless Impedance Pumps From Biological Components: Progress and Challenges

“…Other tubular structures that can be excised and used to create a compliant segment for BLPs include intestine (Herbert et al, 1993), ureter (Narita et al, 2008), or their components such as small-intestine submucosa, for example (Roeder et al, 1999). One can also consider additional treatments that can lower E values of these vessels while retaining their integrity, mild enzymatic treatment being one example (Trabelsi et al, 2020).…”

Pressure-induced collagen degradation in arterial tissue as a potential mechanism for degenerative arterial disease progression

“…Fresh porcine common carotid arteries were excised from 6-monthold Large White pigs (n ¼ 30) weighing approximately 80 kg at the time of slaughter. Excised carotid arteries were taken from the proximal end of the vessel (Trabelsi et al, 2019) and then frozen to À 80 � C at a controlled rate of À 1 � C/min in a cryoprotectant media to maintain mechanical and structural properties during storage (Müller-Schweinitzer, 2009). Prior to testing, vessels were thawed in a water bath at 37 � C to minimise tissue damage (Pegg et al, 1997), washed in PBS to remove any residual cryoprotectant and cut to approximately 30 mm in length for testing.…”