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Extracellular matrix-based biomaterials are currently pursued as an alternative to autologous transplants for the treatment of gingival recession and periodontal disease. These grafts offer improved tissue regeneration without the need for a second operative procedure used in current treatments to remove nonresorbable synthetic biomaterials. However, while decellularization is necessary to minimize the potential immunological impact, it can significantly modify the materials architectural and biochemical properties. By understanding cellular responses, it is possible to more specifically target varying clinical situations. These investigations assess a novel allogenic scaffold derived from the human umbilical vein and determine the effects of two decellularization approaches (osmotic lysis and the surfactant Triton X-100) on the biological and mechanical properties during early remodeling events. Results show Triton X-100 to be significantly more effective at extracting lipids, while the extraction of the scaffolds bulk protein, GAG and DNA similar between the two treatments. Once seeded, scaffolds prepared with osmotic lysis displayed increased cellular proliferation and reduced metabolic activity compared to scaffolds treated with surfactant. Biomechanical properties were largely preserved and similar between the two treatments. These results suggest that by optimizing scaffold processing conditions, biological events associated with remodeling can be modulated to tailor scaffold function for specific clinical applications. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 8-16, 2014. [ABSTRACT FROM AUTHOR]

In the embryonic heart, blood flow is distributed through a bilaterally paired artery system composed of the aortic arches (AAs). The purpose of this study is to establish an understanding of the governing mechanism of microstructural maturation of the AA matrix and its reversibility, toward the desired macroscopic vessel lumen diameter and thickness for healthy, abnormal, and in ovo repaired abnormal mechanical loading. While matrix-remodeling mechanisms were significantly different for normal versus conotruncal banding (CTB), both led to an increase in vessel lumen. Correlated with right-sided flow increase at Hamburger & Hamilton stages 21, intermittent load switching between collagen I and III with elastin and collagen-IV defines the normal process. However, decreases in collagen I, elastin, vascular endothelial growth factor-A, and fibrillin-1 in CTB were recovered almost fully following the CTB-release model, primarily because of the pressure load changes. The complex temporal changes in matrix proteins are illustrated through a predictive finite-element model based on elastin and collagen load-sharing mechanism to achieve lumen area increase and thickness increase resulting from wall shear stress and tissue strain, respectively. The effect of embryonic timing in cardiac interventions on AA microstructure was established where abnormal mechanical loading was selectively restored at the key stage of development. Recovery of the normal mechanical loading via early fetal intervention resulted in delayed microstructural maturation. Temporal elastin increase, correlated with wall shear stress, is required for continuous lumen area growth. NEW & NOTEWORTHY The present study undertakes comparative analyses of the mechanistic differences of the arterial matrix microstructure and dynamics in the three fundamental processes of control, conotruncal banded, and released conotruncal band in avian embryo. Among other findings, this study provides specific evidence on the restorative role of elastin during the early lumen growth process. During vascular development, a novel intermittent load-switching mechanism between elastin and collagen, triggered by a step increase in wall shear stress, governs the chronic vessel lumen cross-sectional area increase. Mimicking the fetal cardiovascular interventions currently performed in humans, the early release of the abnormal mechanical load rescues the arterial microstructure with time lag.

Microparticle image velocimetry (μPIV) is an evolving quantitative methodology to closely and accurately monitor the cardiac flow dynamics and mechanotransduction during vascular morphogenesis. While PIV technique has a long history, contemporary developments in advanced microscopy have significantly expanded its power. This chapter includes three new methods for μPIV acquisition in selected embryonic structures achieved through advanced optical imaging: (1) high-speed confocal scanning of transgenic zebrafish embryos, where the transgenic erythrocytes act as the tracing particles; (2) microinjection of artificial seeding particles in chick embryos visualized with stereomicroscopy; and (3) real-time, time-resolved optical coherence tomography acquisition of vitelline vessel flow profiles in chick embryos, tracking the erythrocytes.