TY - JOUR
T1 - Linking the region-specific tissue microstructure to the biaxial mechanical properties of the porcine left anterior descending artery
AU - Pineda-Castillo, Sergio A.
AU - Aparicio-Ruiz, Santiago
AU - Burns, Madison M.
AU - Laurence, Devin W.
AU - Bradshaw, Elizabeth
AU - Gu, Tingting
AU - Holzapfel, Gerhard A.
AU - Lee, Chung Hao
N1 - Funding Information:
We are deeply grateful for the support of Mr. Colton Ross for his invaluable contribution during study design. We would also like to acknowledge the American Heart Association Scientist Development Grant Award (16SDG27760143) and the Presbyterian Health Foundation Team Science Grant. S.A.P.-C. was supported in part by the Alumni Fellowship from the Graduate College at the University of Oklahoma. D.W.L. was supported by the National Science Foundation Graduate Research Fellowship ( GRF 2019254233 ).
Publisher Copyright:
© 2022
PY - 2022/9/15
Y1 - 2022/9/15
N2 - Coronary atherosclerosis is the main cause of death worldwide. Advancing the understanding of coronary microstructure-based mechanics is fundamental for the development of therapeutic tools and surgical procedures. Although the passive biaxial properties of the coronary arteries have been extensively explored, their regional differences and the relationship between tissue microstructure and mechanics have not been fully characterized. In this study, we characterized the passive biaxial mechanical properties and microstructural properties of the proximal, medial, and distal regions of the porcine left anterior descending artery (LADA). We also attempted to relate the biaxial stress-stretch response of the LADA and its respective birefringent responses to the polarized light for obtaining information about the load-dependent microstructural variations. We found that the LADA extensibility is reduced in the proximal-to-distal direction and that the medial region exhibits more heterogeneous mechanical behavior than the other two regions. We have also observed highly dynamic microstructural behavior where fiber families realign themselves depending on loading. In addition, we found that the microstructure of the distal region exhibited highly aligned fibers along the longitudinal axis of the artery. To verify this microstructural feature, we imaged the LADA specimens with multi-photon microscopy and observed that the adventitia microstructure transitioned from a random fiber network in the proximal region to highly aligned fibers in the distal region. Our findings could offer new perspectives for understanding coronary mechanics and aid in the development of tissue-engineered vascular grafts, which are currently limited due to their mismatch with native tissue in terms of mechanical properties and microstructural features. Statement of significance: The tissue biomechanics of coronary arteries is fundamental for the development of revascularization techniques such as coronary artery bypass. These therapeutics require a deep understanding of arterial mechanics, microstructure, and mechanobiology to prevent graft failure and reoperation. The present study characterizes the unique regional mechanical and microstructural properties of the porcine left anterior descending artery using biaxial testing, polarized-light imaging, and confocal microscopy. This comprehensive characterization provides an improved understanding of the collagen/elastin architecture in response to mechanical loads using a region-specific approach. The unique tissue properties obtained from this study will provide guidance for the selection of anastomotic sites in coronary artery bypass grafting and for the design of tissue-engineered vascular grafts.
AB - Coronary atherosclerosis is the main cause of death worldwide. Advancing the understanding of coronary microstructure-based mechanics is fundamental for the development of therapeutic tools and surgical procedures. Although the passive biaxial properties of the coronary arteries have been extensively explored, their regional differences and the relationship between tissue microstructure and mechanics have not been fully characterized. In this study, we characterized the passive biaxial mechanical properties and microstructural properties of the proximal, medial, and distal regions of the porcine left anterior descending artery (LADA). We also attempted to relate the biaxial stress-stretch response of the LADA and its respective birefringent responses to the polarized light for obtaining information about the load-dependent microstructural variations. We found that the LADA extensibility is reduced in the proximal-to-distal direction and that the medial region exhibits more heterogeneous mechanical behavior than the other two regions. We have also observed highly dynamic microstructural behavior where fiber families realign themselves depending on loading. In addition, we found that the microstructure of the distal region exhibited highly aligned fibers along the longitudinal axis of the artery. To verify this microstructural feature, we imaged the LADA specimens with multi-photon microscopy and observed that the adventitia microstructure transitioned from a random fiber network in the proximal region to highly aligned fibers in the distal region. Our findings could offer new perspectives for understanding coronary mechanics and aid in the development of tissue-engineered vascular grafts, which are currently limited due to their mismatch with native tissue in terms of mechanical properties and microstructural features. Statement of significance: The tissue biomechanics of coronary arteries is fundamental for the development of revascularization techniques such as coronary artery bypass. These therapeutics require a deep understanding of arterial mechanics, microstructure, and mechanobiology to prevent graft failure and reoperation. The present study characterizes the unique regional mechanical and microstructural properties of the porcine left anterior descending artery using biaxial testing, polarized-light imaging, and confocal microscopy. This comprehensive characterization provides an improved understanding of the collagen/elastin architecture in response to mechanical loads using a region-specific approach. The unique tissue properties obtained from this study will provide guidance for the selection of anastomotic sites in coronary artery bypass grafting and for the design of tissue-engineered vascular grafts.
KW - Collagen and elastin microstructure
KW - Constitutive modeling
KW - Coronary artery biomechanics
KW - Multi-photon microscopy
KW - Planar biaxial testing
KW - Polarized spatial frequency domain imaging
UR - http://www.scopus.com/inward/record.url?scp=85135284159&partnerID=8YFLogxK
U2 - 10.1016/j.actbio.2022.07.036
DO - 10.1016/j.actbio.2022.07.036
M3 - Article
C2 - 35905825
AN - SCOPUS:85135284159
VL - 150
SP - 295
EP - 309
JO - Acta Biomaterialia
JF - Acta Biomaterialia
SN - 1742-7061
ER -