Analysis of early embryonic great-vessel microcirculation in zebrafish using high-speed confocal μPIV

Abstract

In the developing cardiovascular system, hemodynamic vascular loading is critical for angiogenesis and cardiovascular adaptation. Normal zebrafish embryos with transgenically-labeled endothelial and red blood cells provide an excellent in vivo model for studying the fluid-flow induced vascular loading. To characterize the developmental hemodynamics of early embryonic great-vessel microcirculation in the zebrafish embryo, two complementary studies (experimental and numerical) are presented. Quantitative comparison of the wall shear stress (WSS) at the first aortic arch (AA1) of wild-type zebrafish embryos during two consecutive developmental stages is presented, using time-resolved confocal micro-particle image velocimetry (µPIV). Analysis showed that there was significant WSS difference between 32 and 48 h post-fertilization (hpf) wild-type embryos, which correlates with normal arch morphogenesis. The vascular distensibility of the arch wall at systole and the acceleration/deceleration rates of time-lapse phase-averaged streamwise blood flow curves were also analyzed. To estimate the influence of a novel intermittent red-blood cell (RBC) loading on the endothelium, a numerical two-phase, volume of fluid (VOF) flow model was further developed with realistic in vivo conditions. These studies showed that near-wall effects and cell clustering increased WSS augmentation at a minimum of 15% when the distance of RBC from arch vessel wall was less than 3 µm or when RBC cell-to-cell distance was less than 3 µm. When compared to a smooth wall, the WSS augmentation increased by a factor of ∼1.4 due to the roughness of the wall created by the endothelial cell profile. These results quantitatively highlight the contribution of individual RBC flow patterns on endothelial WSS in great-vessel microcirculation and will benefit the quantitative understanding of mechanotransduction in embryonic great vessel biology, including arteriovenous malformations (AVM). C.-Y. Chen et al. / Embryonic great vessel microcirculation vascular biology. Endothelial cells (EC) act as mechanosensors and translate the WSS loading into biochemical signals, which further control the downstream intracellular responses and modulate the gene/protein expression pathway [9,12,17]. The effects of altered hemodynamics are well established in the literature: the exposure of human aortic endothelial cells to an oscillatory flow (mean time-averaged shear stress 0.10 Pa) leads to an increase in cell proliferation, in contrast to the unidirectional laminar flow condition (mean shear stress > 1 Pa) [5]. Likewise, WSS loading plays a major role in the etiology of a number of cardiovascular diseases [40], such as atherosclerotic lesion development [18] and congenital heart defects. Particularly, the progression of high-flow arteriovenous malformations (AVM), which are associated with the mutations in the actin receptor-like kinase 1 (Alk1) gene, result in autosomal dominant vascular disease and hereditary hemorrhagic telangiectasia type 2 (HHT2) [3]. Recent studies us...

Moving Domain Computational Fluid Dynamics to Interface with an Embryonic Model of Cardiac Morphogenesis

“…Despite a few studies about aortic arch morphogenesis and vascular morphogenesis [11–15], there is a paucity of literature in developmental embryonic zebrafish cardiac model reconstruction and application of CFD codes to establish quantitative analysis underlying morphological changes during development [16]. One report did directly measure intracardiac pressure in the adult zebrafish [17], however the technique is invasive, causing local flow disturbances when applied to the embryonic circulation.…”

Left atrial ligation alters intracardiac flow patterns and the biomechanical landscape in the chick embryo

“…Numerous studies using chick (Gessner, 1966;Hogers et al, 1997Hogers et al, , 1999Reckova et al, 2003;Lucitti et al, 2006) and zebrafish (Hove et al, 2003;Chen et al, 2011;Corti et al, 2011) embryos support the role of hemodynamics in modifying cardiovascular growth, morphogenesis, and remodeling. It is well established that WSS is a key environmental factor affecting cardiovascular development in the embryo and adaptation in the adult (Rodbard, 1975;Langille and O'Donnell, 1986;Girerd et al, 1996;Bayer et al, 1999;Culver and Dickinson, 2010).…”

Microfluidic Transportation Control of Larval Zebrafish through Optomotor Regulations under a Pressure-Driven Flow

“…Zebrafish (Danio rerio) are unarguably considered to be one of the most important animal models that have been used for studies on neurobiological development [1], cardiac development [2][3][4], pharmacological research [5], genetic modeling [6], and toxicological research [7,8]. Most zebrafish-related research has been carried out in their early larval stages, where the larvae are transparent and small for applications of powerful imaging tools and genetic modification.…”