Structure and hemodynamics of vascular networks in the chorioallantoic membrane of the chicken.

Maibier, Martin; Reglin, Bettina; Nitzsche, Bianca; Xiang, Weiwei; Rong, Wen Wei; Hoffmann, Björn; Djonov, Valentin; Secomb, Timothy W; Pries, Axel R (2016). Structure and hemodynamics of vascular networks in the chorioallantoic membrane of the chicken. American journal of physiology - heart and circulatory physiology, 311(4), H913-H926. American Physiological Society 10.1152/ajpheart.00786.2015

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The chick chorioallantoic membrane (CAM) is extensively used as an in vivo model. Here, structure and hemodynamics of CAM vessel trees were analyzed and compared with predictions of Murray's law. CAM microvascular networks of Hamburger-Hamilton stage 40 chick embryos were scanned by videomicroscopy. Three networks with ∼3,800, 580, and 480 segments were digitally reconstructed, neglecting the capillary mesh. Vessel diameters (D) and segment lengths were measured, and generation numbers and junctional exponents at bifurcations were derived. In selected vessels, flow velocities (v) and hematocrit were measured. Hemodynamic simulations, incorporating the branching of capillaries from preterminal vessels, were used to estimate v, volume flow, shear stress (τ), and pressure for all segments of the largest network. For individual arteriovenous flow pathways, terminal arterial and venous generation numbers are negatively correlated, leading to low variability of total topological and morphological pathway lengths. Arteriolar velocity is proportional to diameter (v∝D(1.03) measured, v∝D(0.93) modeling), giving nearly uniform τ levels (τ∝D(0.05)). Venular trees exhibit slightly higher exponents (v∝D(1.3), τ∝D(0.38)). Junctional exponents at divergent and convergent bifurcations were 2.05 ± 1.13 and 1.97 ± 0.95 (mean ± SD) in contrast to the value 3 predicted by Murray's law. In accordance with Murray's law, τ levels are (nearly) maintained in CAM arterial (venular) trees, suggesting vascular adaptation to shear stress. Arterial and venous trees show an interdigitating arrangement providing homogeneous flow pathway properties and have preterminal capillary branches. These properties may facilitate efficient oxygen exchange in the CAM during rapid embryonic growth.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > Pre-clinic Human Medicine > Institute of Anatomy
04 Faculty of Medicine > Pre-clinic Human Medicine > Institute of Anatomy > Topographical and Clinical Anatomy

UniBE Contributor:

Djonov, Valentin

Subjects:

600 Technology > 610 Medicine & health
500 Science > 570 Life sciences; biology

ISSN:

0363-6135

Publisher:

American Physiological Society

Language:

English

Submitter:

David Christian Haberthür

Date Deposited:

28 Dec 2016 10:58

Last Modified:

28 Dec 2016 10:58

Publisher DOI:

10.1152/ajpheart.00786.2015

PubMed ID:

27402670

Uncontrolled Keywords:

Murray's law; angiogenesis; cardiovascular modeling; chick embryo; microcirculation

BORIS DOI:

10.7892/boris.91730

URI:

https://boris.unibe.ch/id/eprint/91730

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