Integration of polarized spatial frequency domain imaging (pSFDI) with a biaxial mechanical testing system for quantification of load-dependent collagen architecture in soft collagenous tissues

Jett, Samuel; Hudson, Luke T.; Baumwart, Ryan; Bohnstedt, Bradley N.; Mir, Arshid; Burkhart, Harold M.; Holzapfel, Gerhard; Wu, Yi; Lee, Chung‐Hao

doi:10.1016/j.actbio.2019.11.028

Cited by 46 publications

(39 citation statements)

References 99 publications

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“…Extensive studies on the chordae-leaflet insertion have not yet to be performed for TV chordae tissues. In our lab, we recently completed a pilot study by using the polarized spatial frequency domain imaging (pSFDI) modality [66,67] to analyze the load-dependent collagen fiber orientations of the strut chordae insertions of porcine MV and TV anterior leaflets (MVAL and TVAL). Briefly, in the study we loaded leaflet-chordae-papillary muscle entities to physiologically representative loading (MVAL: 1.4 N and TVAL: 1.2 N), and pSFDI was performed to quantify the collagen fiber architecture at various states of the force-deformation curve ( Figure 6).…”

Section: Load-dependent Collagen Fiber Architecture Of the Chordae-lementioning

confidence: 99%

“…It would also be useful to better understand the contributions of the elastin sheath to the chordae's overall mechanical behaviors through testing the same tissues before and after sheath removal. Other useful information could be found through new microstructural quantification technologies, such as polarized spatial frequency domain imaging, allowing for an understanding of the load-dependent collagen fiber architecture, especially at the insertion regions [66,67,69].…”

Section: Closing Remarks and Future Prospectsmentioning

confidence: 99%

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Mechanics and Microstructure of the Atrioventricular Heart Valve Chordae Tendineae: A Review

Ross

Zheng

et al. 2020

Bioengineering

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The atrioventricular heart valves (AHVs) are responsible for directing unidirectional blood flow through the heart by properly opening and closing the valve leaflets, which are supported in their function by the chordae tendineae and the papillary muscles. Specifically, the chordae tendineae are critical to distributing forces during systolic closure from the leaflets to the papillary muscles, preventing leaflet prolapse and consequent regurgitation. Current therapies for chordae failure have issues of disease recurrence or suboptimal treatment outcomes. To improve those therapies, researchers have sought to better understand the mechanics and microstructure of the chordae tendineae of the AHVs. The intricate structures of the chordae tendineae have become of increasing interest in recent literature, and there are several key findings that have not been comprehensively summarized in one review. Therefore, in this review paper, we will provide a summary of the current state of biomechanical and microstructural characterizations of the chordae tendineae, and also discuss perspectives for future studies that will aid in a better understanding of the tissue mechanics–microstructure linking of the AHVs’ chordae tendineae, and thereby improve the therapeutics for heart valve diseases caused by chordae failures.

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Section: Load-dependent Collagen Fiber Architecture Of the Chordae-lementioning

confidence: 99%

Section: Closing Remarks and Future Prospectsmentioning

confidence: 99%

Mechanics and Microstructure of the Atrioventricular Heart Valve Chordae Tendineae: A Review

Ross

Zheng

et al. 2020

Bioengineering

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“…The DOA stems from the structural anisotropy of the collagen fibers, and therefore, we may attribute the optical anisotropy within the sample to the structural alignment of the CFA (DOA = 1, fully aligned case). Please refer to more details of the pSFDI data analysis in Appendix A , and further information about the pSFDI theory can be found in the recent studies by Goth et al (2016, 2019) [ 42 , 44 ] and Jett et al (2020) [ 45 ].…”

Section: Methodsmentioning

confidence: 99%

“…The pSFDI imaging technique combines the ability of co-polarized imaging to quantify the birefringent fiber structures with the depth-discrimination capabilities of SFDI. Interested readers can refer to more details in [44,45,62]. During the polarized spatial frequency domain imaging procedure, polarization-state images (2560 × 2048 pixels) for each phase shift were obtained, and the acquired 37 images were then smoothed via an in-house MATLAB program using convolution with a 5 × 5 uniform kernel.…”

Section: Conflicts Of Interestmentioning

confidence: 99%

“…Previously, Goth et al [44] displayed the collagen microstructural quantification capabilities of pSFDI using ovine aortic heart valve leaflets at an unloaded state; however, they did not yet highlight the load-dependent architectural changes. Recently, our group has developed a combined instrument, which integrated an in-house pSFDI device with a commercial biaxial testing system, to investigate the load-dependent changes in the CFAs for bovine tendon tissues, with highly-aligned CFAs, and a representative porcine mitral valve anterior leaflet with more dispersed CFAs [45].…”

Section: Introductionmentioning

confidence: 99%

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A Pilot Study on Linking Tissue Mechanics with Load-Dependent Collagen Microstructures in Porcine Tricuspid Valve Leaflets

et al. 2020

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The tricuspid valve (TV) is composed of three leaflets that coapt during systole to prevent deoxygenated blood from re-entering the right atrium. The connection between the TV leaflets’ microstructure and the tissue-level mechanical responses has yet to be fully understood in the TV biomechanics society. This pilot study sought to examine the load-dependent collagen fiber architecture of the three TV leaflets, by employing a multiscale, combined experimental approach that utilizes tissue-level biaxial mechanical characterizations, micro-level collagen fiber quantification, and histological analysis. Our results showed that the three TV leaflets displayed greater extensibility in the tissues’ radial direction than in the circumferential direction, consistently under different applied biaxial tensions. Additionally, collagen fibers reoriented towards the direction of the larger applied load, with the largest changes in the alignment of the collagen fibers under radially-dominant loading. Moreover, collagen fibers in the belly region of the TV leaflets were found to experience greater reorientations compared to the tissue region closer to the TV annulus. Furthermore, histological examinations of the TV leaflets displayed significant regional variation in constituent mass fraction, highlighting the heterogeneous collagen microstructure. The combined experimental approach presented in this work enables the connection of tissue mechanics, collagen fiber microstructure, and morphology for the TV leaflets. This experimental methodology also provides a new research platform for future developments, such as multiscale models for the TVs, and the design of bioprosthetic heart valves that could better mimic the mechanical, microstructural, and morphological characteristics of the native tricuspid valve leaflets.

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Integrated Perspective of Scaffold Designing and Multiscale Mechanics in Cardiac Bioengineering

Lou

Lopez

Nautiyal

et al. 2021

Advanced NanoBiomed Research

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According to a World Health Organization (WHO) report in 2017, [1] cardiovascular diseases (CVDs) are the foremost cause of mortality, with 85% attributed to stroke and heart attack (or myocardial infarction [MI]) worldwide. The 2019 American Heart Association report [2] indicates that CVD is the leading lethal disease in the U.S., with 840 768 deaths in 2016. There is one new MI case in the U.S. every 40 s, contributing to about $351 billion in costs in 2014À2015. [2] MI gradually develops and deteriorates into inflammation, apoptosis, and inelastic fibrous scar, eventually leading to congestive heart failure (CHF). [3] Due to cardiomyocytes' (CMs) limited regeneration and proliferation ability, the effective long-term MI and CHF treatment is transplantation. There were over 3500 candidates on the heart transplant waiting list by the end of 2020, according to the national data [4] from the USA. Department of Health and Human Services. Shortage of organ donation sources, organ storage and maintenance, and post-transplantation immunologic rejection are tricky issues that are difficult to solve. Reconstruction of cardiac tissue using 3D scaffold or scaffold-free techniques has emerged as a promising alternative treatment approach.Cardiac bioengineering aims to investigate or rebuild illfunctioning myocardium tissues via CMs, scaffold-free cell sheet substrates, and implantable cell-seeded scaffolds. [3] Scaffold-free approaches include miRNA clusters, [5] spheroid models, [6] scaffold-free multiple-component cell cultures, [3,7] injectable hydrogels, [8] and organ on a chip. [9] These strategies permit direct delivery of cells or cell composites to infarcted myocardium and enable thick 3D tissue patch implantation with enhanced cell engraftment capacity. Some scaffold-free approaches can also be exploited in in vitro pathological cardiac models or ex vivo platforms for new therapy efficacy and cardiotoxicity evaluation. [6,7,9] Unlike scaffold-free pathways, cardiac scaffolds provide mechanical support to the myocardium, establish contractility/pumping, and lessen myocardial dilation and myocardial wall stress. [3] Meanwhile, significant progress has been made in stem cellderived CM tissue preparation; [10][11][12] scaffold and extracellular matrix (ECM) construction; [13][14][15][16][17] scaffold-free in situ injectable pathway development; [5][6][7]9] cell seeding, proliferation, and viabil-

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Integration of polarized spatial frequency domain imaging (pSFDI) with a biaxial mechanical testing system for quantification of load-dependent collagen architecture in soft collagenous tissues

Cited by 46 publications

References 99 publications

Mechanics and Microstructure of the Atrioventricular Heart Valve Chordae Tendineae: A Review

Mechanics and Microstructure of the Atrioventricular Heart Valve Chordae Tendineae: A Review

A Pilot Study on Linking Tissue Mechanics with Load-Dependent Collagen Microstructures in Porcine Tricuspid Valve Leaflets

Integrated Perspective of Scaffold Designing and Multiscale Mechanics in Cardiac Bioengineering

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