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Żukowski S, Cornelissen AJM, Osselin F, Douady S, Szymczak P. Breakthrough-induced loop formation in evolving transport networks. Proc Natl Acad Sci U S A 2024; 121:e2401200121. [PMID: 38985758 PMCID: PMC11260131 DOI: 10.1073/pnas.2401200121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Accepted: 06/15/2024] [Indexed: 07/12/2024] Open
Abstract
Transport networks, such as vasculature or river networks, provide key functions in organisms and the environment. They usually contain loops whose significance for the stability and robustness of the network is well documented. However, the dynamics of their formation is usually not considered. Such structures often grow in response to the gradient of an external field. During evolution, extending branches compete for the available flux of the field, which leads to effective repulsion between them and screening of the shorter ones. Yet, in remarkably diverse processes, from unstable fluid flows to the canal system of jellyfish, loops suddenly form near the breakthrough when the longest branch reaches the boundary of the system. We provide a physical explanation for this universal behavior. Using a 1D model, we explain that the appearance of effective attractive forces results from the field drop inside the leading finger as it approaches the outlet. Furthermore, we numerically study the interactions between two fingers, including screening in the system and its disappearance near the breakthrough. Finally, we perform simulations of the temporal evolution of the fingers to show how revival and attraction to the longest finger leads to dynamic loop formation. We compare the simulations to the experiments and find that the dynamics of the shorter finger are well reproduced. Our results demonstrate that reconnection is a prevalent phenomenon in systems driven by diffusive fluxes, occurring both when the ratio of the mobility inside the growing structure to the mobility outside is low and near the breakthrough.
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Affiliation(s)
- Stanisław Żukowski
- Institute of Theoretical Physics, Faculty of Physics, University of Warsaw, Warsaw02-093, Poland
- Laboratoire Matière et Systèmes Complexes, UMR 7057, CNRS & Université Paris Cité, Paris75013, France
| | | | - Florian Osselin
- Institut des Sciences de la Terre d’Orléans, UMR 7327, CNRS & BRGM & Université d’Orléans, Orléans45100, France
| | - Stéphane Douady
- Laboratoire Matière et Systèmes Complexes, UMR 7057, CNRS & Université Paris Cité, Paris75013, France
| | - Piotr Szymczak
- Institute of Theoretical Physics, Faculty of Physics, University of Warsaw, Warsaw02-093, Poland
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2
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Lorthois S. Intimate contact between red blood cells and vessel walls is sufficient to stabilize capillary networks during development. Proc Natl Acad Sci U S A 2024; 121:e2401819121. [PMID: 38536758 PMCID: PMC10998565 DOI: 10.1073/pnas.2401819121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2024] Open
Affiliation(s)
- Sylvie Lorthois
- Institut de Mécanique des Fluides de Toulouse, Université de Toulouse, CNRS, 31400Toulouse, France
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3
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Żukowski S, Morawiecki P, Seybold H, Szymczak P. Through history to growth dynamics: deciphering the evolution of spatial networks. Sci Rep 2022; 12:20407. [PMID: 36437299 PMCID: PMC9701698 DOI: 10.1038/s41598-022-24656-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 11/18/2022] [Indexed: 11/29/2022] Open
Abstract
Many ramified, network-like patterns in nature, such as river networks or blood vessels, form as a result of unstable growth of moving boundaries in an external diffusive field. Here, we pose the inverse problem for the network growth-can the growth dynamics be inferred from the analysis of the final pattern? We show that by evolving the network backward in time one can not only reconstruct the growth rules but also get an insight into the conditions under which branch splitting occurs. Determining the growth rules from a single snapshot in time is particularly important for growth processes so slow that they cannot be directly observed, such as growth of river networks and deltas or cave passages. We apply this approach to analyze the growth of a real river network in Vermont, USA. We determine its growth rule and argue that branch splitting events are triggered by an increase in the tip growth velocity.
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Affiliation(s)
- Stanisław Żukowski
- Institute of Theoretical Physics, Faculty of Physics, University of Warsaw, Warsaw, Poland
- Laboratoire Matière et Systèmes Complexes (MSC), UMR 7057, CNRS & Université Paris Cité, Paris, France
| | - Piotr Morawiecki
- Department of Mathematical Sciences, University of Bath, Bath, UK
| | - Hansjörg Seybold
- Department of Environmental System Science, ETH Zürich, Zürich, Switzerland
| | - Piotr Szymczak
- Institute of Theoretical Physics, Faculty of Physics, University of Warsaw, Warsaw, Poland.
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4
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Padmanaban P, Chizari A, Knop T, Zhang J, Trikalitis VD, Koopman B, Steenbergen W, Rouwkema J. Assessment of flow within developing chicken vasculature and biofabricated vascularized tissues using multimodal imaging techniques. Sci Rep 2021; 11:18251. [PMID: 34521868 PMCID: PMC8440514 DOI: 10.1038/s41598-021-97008-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 08/19/2021] [Indexed: 11/21/2022] Open
Abstract
Fluid flow shear stresses are strong regulators for directing the organization of vascular networks. Knowledge of structural and flow dynamics information within complex vasculature is essential for tuning the vascular organization within engineered tissues, by manipulating flows. However, reported investigations of vascular organization and their associated flow dynamics within complex vasculature over time are limited, due to limitations in the available physiological pre-clinical models, and the optical inaccessibility and aseptic nature of these models. Here, we developed laser speckle contrast imaging (LSCI) and side-stream dark field microscopy (SDF) systems to map the vascular organization, spatio-temporal blood flow fluctuations as well as erythrocytes movements within individual blood vessels of developing chick embryo, cultured within an artificial eggshell system. By combining imaging data and computational simulations, we estimated fluid flow shear stresses within multiscale vasculature of varying complexity. Furthermore, we demonstrated the LSCI compatibility with bioengineered perfusable muscle tissue constructs, fabricated via molding techniques. The presented application of LSCI and SDF on perfusable tissues enables us to study the flow perfusion effects in a non-invasive fashion. The gained knowledge can help to use fluid perfusion in order to tune and control multiscale vascular organization within engineered tissues.
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Affiliation(s)
- Prasanna Padmanaban
- Vascularization Lab, Department of Biomechanical Engineering, Technical Medical Centre, Faculty of Engineering Technology, University of Twente, 7500 AE, Enschede, The Netherlands
| | - Ata Chizari
- Biomedical Photonic Imaging, Technical Medical Centre, Faculty of Science and Technology, University of Twente, 7500 AE, Enschede, The Netherlands
| | - Tom Knop
- Biomedical Photonic Imaging, Technical Medical Centre, Faculty of Science and Technology, University of Twente, 7500 AE, Enschede, The Netherlands
| | - Jiena Zhang
- Vascularization Lab, Department of Biomechanical Engineering, Technical Medical Centre, Faculty of Engineering Technology, University of Twente, 7500 AE, Enschede, The Netherlands
| | - Vasileios D Trikalitis
- Vascularization Lab, Department of Biomechanical Engineering, Technical Medical Centre, Faculty of Engineering Technology, University of Twente, 7500 AE, Enschede, The Netherlands
| | - Bart Koopman
- Vascularization Lab, Department of Biomechanical Engineering, Technical Medical Centre, Faculty of Engineering Technology, University of Twente, 7500 AE, Enschede, The Netherlands
| | - Wiendelt Steenbergen
- Biomedical Photonic Imaging, Technical Medical Centre, Faculty of Science and Technology, University of Twente, 7500 AE, Enschede, The Netherlands.
| | - Jeroen Rouwkema
- Vascularization Lab, Department of Biomechanical Engineering, Technical Medical Centre, Faculty of Engineering Technology, University of Twente, 7500 AE, Enschede, The Netherlands.
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5
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Kirkegaard JB, Sneppen K. Optimal Transport Flows for Distributed Production Networks. PHYSICAL REVIEW LETTERS 2020; 124:208101. [PMID: 32501061 DOI: 10.1103/physrevlett.124.208101] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 04/23/2020] [Indexed: 06/11/2023]
Abstract
Network flows often exhibit a hierarchical treelike structure that can be attributed to the minimization of dissipation. The common feature of such systems is a single source and multiple sinks (or vice versa). In contrast, here we study networks with only a single source and sink. These systems can arise from secondary purposes of the networks, such as blood sugar regulation through insulin production. Minimization of dissipation in these systems leads to vascular shunting, a single vessel connecting the inlet and outlet. We show instead how optimizing the transport time yields network topologies that match those observed in the insulin-producing pancreatic islets. These are patterns of periphery-to-center and center-to-periphery flows. The obtained flow networks are broadly independent of how the flow velocity depends on the flow flux, but continuous and discontinuous phase transitions appear at extreme flux dependencies. Lastly, we show how constraints on flows can lead to buckling of the branches of the network, a feature that is also observed in pancreatic islets.
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Affiliation(s)
| | - Kim Sneppen
- Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
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6
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Ronellenfitsch H, Katifori E. Phenotypes of Vascular Flow Networks. PHYSICAL REVIEW LETTERS 2019; 123:248101. [PMID: 31922876 DOI: 10.1103/physrevlett.123.248101] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Indexed: 06/10/2023]
Abstract
Complex distribution networks are pervasive in biology. Examples include nutrient transport in the slime mold Physarum polycephalum as well as mammalian and plant venation. Adaptive rules are believed to guide development of these networks and lead to a reticulate, hierarchically nested topology that is both efficient and resilient against perturbations. However, as of yet, no mechanism is known that can generate such networks on all scales. We show how hierarchically organized reticulation can be constructed and maintained through spatially correlated load fluctuations on a particular length scale. We demonstrate that the network topologies generated represent a trade-off between optimizing transport efficiency, construction cost, and damage robustness and identify the Pareto-efficient front that evolution is expected to favor and select for. We show that the typical fluctuation length scale controls the position of the networks on the Pareto front and thus on the spectrum of venation phenotypes.
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Affiliation(s)
- Henrik Ronellenfitsch
- Department of Mathematics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Eleni Katifori
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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7
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Glioblastoma multiforme restructures the topological connectivity of cerebrovascular networks. Sci Rep 2019; 9:11757. [PMID: 31409816 PMCID: PMC6692362 DOI: 10.1038/s41598-019-47567-w] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 07/19/2019] [Indexed: 12/16/2022] Open
Abstract
Glioblastoma multiforme alters healthy tissue vasculature by inducing angiogenesis and vascular remodeling. To fully comprehend the structural and functional properties of the resulting vascular network, it needs to be studied collectively by considering both geometric and topological properties. Utilizing Single Plane Illumination Microscopy (SPIM), the detailed capillary structure in entire healthy and tumor-bearing mouse brains could be resolved in three dimensions. At the scale of the smallest capillaries, the entire vascular systems of bulk U87- and GL261-glioblastoma xenografts, their respective cores, and healthy brain hemispheres were modeled as complex networks and quantified with fundamental topological measures. All individual vessel segments were further quantified geometrically and modular clusters were uncovered and characterized as meta-networks, facilitating an analysis of large-scale connectivity. An inclusive comparison of large tissue sections revealed that geometric properties of individual vessels were altered in glioblastoma in a relatively subtle way, with high intra- and inter-tumor heterogeneity, compared to the impact on the vessel connectivity. A network topology analysis revealed a clear decomposition of large modular structures and hierarchical network organization, while preserving most fundamental topological classifications, in both tumor models with distinct growth patterns. These results augment our understanding of cerebrovascular networks and offer a topological assessment of glioma-induced vascular remodeling. The findings may help understand the emergence of hypoxia and necrosis, and prove valuable for therapeutic interventions such as radiation or antiangiogenic therapy.
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8
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Chang SS, Roper M. Microvscular networks with uniform flow. J Theor Biol 2019; 462:48-64. [PMID: 30420333 PMCID: PMC6599712 DOI: 10.1016/j.jtbi.2018.10.049] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2018] [Revised: 10/11/2018] [Accepted: 10/25/2018] [Indexed: 02/03/2023]
Abstract
Within animals, oxygen exchange occurs within vascular transport networks containing potentially billions of microvessels that are distributed throughout the body. By comparison, large blood vessels are theorized to minimize transport costs, leading to tree-like networks that satisfy Murray's law. We know very little about the principles underlying the organization of healthy micro-vascular networks. Indeed capillary networks must also perfuse tissues with oxygen, and efficient perfusion may be incompatible with minimization of transport costs. While networks that minimize transport costs have been well-studied, other optimization principles have received much less scrutiny. In this work we derive the morphology of networks that uniformize blood flow distribution, inspired by the zebrafish trunk micro-vascular network. To find uniform flow networks, we devise a gradient descent algorithm able to optimize arbitrary differentiable objective functions on transport networks, while exactly respecting arbitrary differentiable constraint functions. We prove that in a class of networks that we call stackable, which includes a model capillary bed, the uniform flow network will have the same flow as a uniform conductance network, i.e., in which all edges have the same conductance. This result agrees with uniform flow capillary bed network found by the algorithm. We also show that the uniform flow completely explains the observed radii within the zebrafish trunk vasculature. In addition to deriving new results on optimization of uniform flow in micro-vascular networks, our algorithm provides a general method for testing hypotheses about possible optimization principles underlying real microvascular networks, including exposing tradeoffs between flow uniformity and transport cost.
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Affiliation(s)
- Shyr-Shea Chang
- Department of Mathematics, University of California Los Angeles, Los Angeles, CA 90095, USA.
| | - Marcus Roper
- Department of Mathematics, University of California Los Angeles, Los Angeles, CA 90095, USA; Department of Biomathematics, University of California Los Angeles, Los Angeles, CA 90095, USA
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9
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Direct imaging of capillaries reveals the mechanism of arteriovenous interlacing in the chick chorioallantoic membrane. Commun Biol 2018; 1:235. [PMID: 30588514 PMCID: PMC6303259 DOI: 10.1038/s42003-018-0229-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 11/13/2018] [Indexed: 11/08/2022] Open
Abstract
Understanding vascular development in vertebrates is an important scientific endeavor. Normal vasculatures generally start off as a disorganized capillary lattice which progressively matures into a well-organized vascular loop comprising a hierarchy of arteries and veins. One striking feature of vascular development is the interlacing of arteries and veins. How arteries and veins manage to avoid themselves and interlace with such a perfect architecture is not understood. Here we present a detailed view of the development of the vasculature in the chorioallantoic membrane of the chicken embryo. We find that the origin of arteriovenous interlacing lies in the presence of an increased hemodynamic resistance at the distal part of the arteries due to vascular flattening onto the ectodermal surface. This reduces the vascular conductance distally, thus repelling veins away. In more proximal parts, vessels round off into cylinders and the increased flow attracts veins.
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10
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Smith AF, Nitzsche B, Maibier M, Pries AR, Secomb TW. Microvascular hemodynamics in the chick chorioallantoic membrane. Microcirculation 2018; 23:512-522. [PMID: 27510444 DOI: 10.1111/micc.12301] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 08/08/2016] [Indexed: 01/21/2023]
Abstract
OBJECTIVE The microvasculature of the CAM in the developing chick embryo is characterized by interdigitating arteriolar and venular trees, connected at multiple points along their lengths to a mesh-like capillary plexus. Theoretical modeling techniques were employed to investigate the resulting hemodynamic characteristics of the CAM. METHODS Based on previously obtained anatomical data, a model was developed in which the capillary plexus was treated as a porous medium. Supply of blood from arterioles and drainage into venules were represented by distributions of flow sources and sinks. Predicted flow velocities were compared with measurements in arterioles and venules obtained via video microscopy. RESULTS If it was assumed that blood flowed into and out of the capillary plexus only at the ends of terminal arterioles and venules, the predicted velocities increased with decreasing diameter in vessels below 50 μm in diameter, contrary to the observations. Distributing sources/sinks along arterioles/venules led to velocities consistent with the data. CONCLUSIONS These results imply that connections to the capillary plexus distributed along the arterioles and venules strongly affect the hemodynamic characteristics of the CAM. The theoretical model provides a basis for quantitative simulations of structural adaptation in CAM networks in response to hemodynamic stimuli.
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Affiliation(s)
- Amy F Smith
- Microcirculation Division, University of Arizona, Tucson, AZ, USA
| | | | - Martin Maibier
- Department of Physiology, Charité Berlin, Berlin, Germany
| | - Axel R Pries
- Department of Physiology, Charité Berlin, Berlin, Germany
| | - Timothy W Secomb
- Microcirculation Division, University of Arizona, Tucson, AZ, USA. .,Department of Physiology, University of Arizona, Tucson, AZ, USA.
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11
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Clément R, Mauroy B, Cornelissen AJM. Tissue growth pressure drives early blood flow in the chicken yolk sac. Dev Dyn 2017; 246:573-584. [PMID: 28474848 DOI: 10.1002/dvdy.24516] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 04/26/2017] [Accepted: 04/26/2017] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND Understanding how molecular and physical cues orchestrate vascular morphogenesis is a challenge for developmental biology. Only little attention has been paid to the impact of mechanical stress caused by tissue growth on early blood distribution. Here we study the peripheral accumulation of blood in the chicken embryonic yolk sac, which precedes sinus vein formation. RESULTS We report that blood accumulation starts before heart-induced blood circulation. We hypothesized that the driving force for the primitive blood flow is a growth-induced gradient of tissue pressure in the yolk sac mesoderm. Therefore, we studied embryos in which heart development was arrested after 2 days of incubation, and found that yolk sac growth and blood peripheral accumulation still occurred. This suggests that tissue growth is sufficient to initiate the flow and the formation of the sinus vein, whereas heart contractions are not required. We designed a simple mathematical model which makes explicit the growth-induced pressure gradient and the subsequent blood accumulation, and show that growth can indeed account for the observed blood accumulation. CONCLUSIONS This study shows that tissue growth pressure can drive early blood flow, and suggests that the mechanical environment, beyond hemodynamics, can contribute to vascular morphogenesis. Developmental Dynamics 246:573-584, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Raphaël Clément
- Laboratoire J.-A. Dieudonné, Université Côte d'Azur and CNRS UMR 7351, Parc Valrose, Nice, France.,Aix Marseille Univ, CNRS, IBDM, Marseille, France
| | - Benjamin Mauroy
- Laboratoire J.-A. Dieudonné, Université Côte d'Azur and CNRS UMR 7351, Parc Valrose, Nice, France
| | - Annemiek J M Cornelissen
- Laboratoire Matière et Systèmes Complexes (MSC), University Paris Diderot and CNRS UMR 7057, Paris, France
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12
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Boselli F, Freund JB, Vermot J. Blood flow mechanics in cardiovascular development. Cell Mol Life Sci 2015; 72:2545-59. [PMID: 25801176 PMCID: PMC4457920 DOI: 10.1007/s00018-015-1885-3] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Revised: 02/25/2015] [Accepted: 03/12/2015] [Indexed: 11/29/2022]
Abstract
Hemodynamic forces are fundamental to development. Indeed, much of cardiovascular morphogenesis reflects a two-way interaction between mechanical forces and the gene network activated in endothelial cells via mechanotransduction feedback loops. As these interactions are becoming better understood in different model organisms, it is possible to identify common mechanogenetic rules, which are strikingly conserved and shared in many tissues and species. Here, we discuss recent findings showing how hemodynamic forces potentially modulate cardiovascular development as well as the underlying fluid and tissue mechanics, with special attention given to the flow characteristics that are unique to the small scales of embryos.
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Affiliation(s)
- Francesco Boselli
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France,
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13
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Quantification of blood flow and topology in developing vascular networks. PLoS One 2014; 9:e96856. [PMID: 24823933 PMCID: PMC4019654 DOI: 10.1371/journal.pone.0096856] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 04/11/2014] [Indexed: 11/19/2022] Open
Abstract
Since fluid dynamics plays a critical role in vascular remodeling, quantification of the hemodynamics is crucial to gain more insight into this complex process. Better understanding of vascular development can improve prediction of the process, and may eventually even be used to influence the vascular structure. In this study, a methodology to quantify hemodynamics and network structure of developing vascular networks is described. The hemodynamic parameters and topology are derived from detailed local blood flow velocities, obtained by in vivo micro-PIV measurements. The use of such detailed flow measurements is shown to be essential, as blood vessels with a similar diameter can have a large variation in flow rate. Measurements are performed in the yolk sacs of seven chicken embryos at two developmental stages between HH 13+ and 17+. A large range of flow velocities (1 µm/s to 1 mm/s) is measured in blood vessels with diameters in the range of 25–500 µm. The quality of the data sets is investigated by verifying the flow balances in the branching points. This shows that the quality of the data sets of the seven embryos is comparable for all stages observed, and the data is suitable for further analysis with known accuracy. When comparing two subsequently characterized networks of the same embryo, vascular remodeling is observed in all seven networks. However, the character of remodeling in the seven embryos differs and can be non-intuitive, which confirms the necessity of quantification. To illustrate the potential of the data, we present a preliminary quantitative study of key network topology parameters and we compare these with theoretical design rules.
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14
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Lorthois S, Lauwers F, Cassot F. Tortuosity and other vessel attributes for arterioles and venules of the human cerebral cortex. Microvasc Res 2014; 91:99-109. [DOI: 10.1016/j.mvr.2013.11.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 11/13/2013] [Accepted: 11/18/2013] [Indexed: 01/02/2023]
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15
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LeBlanc AJ, Krishnan L, Sullivan CJ, Williams SK, Hoying JB. Microvascular repair: post-angiogenesis vascular dynamics. Microcirculation 2013; 19:676-95. [PMID: 22734666 DOI: 10.1111/j.1549-8719.2012.00207.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Vascular compromise and the accompanying perfusion deficits cause or complicate a large array of disease conditions and treatment failures. This has prompted the exploration of therapeutic strategies to repair or regenerate vasculatures, thereby establishing more competent microcirculatory beds. Growing evidence indicates that an increase in vessel numbers within a tissue does not necessarily promote an increase in tissue perfusion. Effective regeneration of a microcirculation entails the integration of new stable microvessel segments into the network via neovascularization. Beginning with angiogenesis, neovascularization entails an integrated series of vascular activities leading to the formation of a new mature microcirculation, and includes vascular guidance and inosculation, vessel maturation, pruning, AV specification, network patterning, structural adaptation, intussusception, and microvascular stabilization. While the generation of new vessel segments is necessary to expand a network, without the concomitant neovessel remodeling and adaptation processes intrinsic to microvascular network formation, these additional vessel segments give rise to a dysfunctional microcirculation. While many of the mechanisms regulating angiogenesis have been detailed, a thorough understanding of the mechanisms driving post-angiogenesis activities specific to neovascularization has yet to be fully realized, but is necessary to develop effective therapeutic strategies for repairing compromised microcirculations as a means to treat disease.
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Affiliation(s)
- Amanda J LeBlanc
- Cardiovascular Innovation Institute, Jewish Hospital and St. Mary's Healthcare and University of Louisville, Louisville, Kentucky 40202, USA
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16
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Okkels F, Jacobsen JCB. Dynamic adaption of vascular morphology. Front Physiol 2012; 3:390. [PMID: 23060814 PMCID: PMC3462325 DOI: 10.3389/fphys.2012.00390] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Accepted: 09/12/2012] [Indexed: 12/03/2022] Open
Abstract
The structure of vascular networks adapts continuously to meet changes in demand of the surrounding tissue. Most of the known vascular adaptation mechanisms are based on local reactions to local stimuli such as pressure and flow, which in turn reflects influence from the surrounding tissue. Here we present a simple two-dimensional model in which, as an alternative approach, the tissue is modeled as a porous medium with intervening sharply defined flow channels. Based on simple, physiologically realistic assumptions, flow-channel structure adapts so as to reach a configuration in which all parts of the tissue are supplied. A set of model parameters uniquely determine the model dynamics, and we have identified the region of the best-performing model parameters (a global optimum). This region is surrounded in parameter space by less optimal model parameter values, and this separation is characterized by steep gradients in the related fitness landscape. Hence it appears that the optimal set of parameters tends to localize close to critical transition zones. Consequently, while the optimal solution is stable for modest parameter perturbations, larger perturbations may cause a profound and permanent shift in systems characteristics. We suggest that the system is driven toward a critical state as a consequence of the ongoing parameter optimization, mimicking an evolutionary pressure on the system.
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Affiliation(s)
- Fridolin Okkels
- Department of Micro- and Nanotechnology, Technical University of Denmark Lyngby, Denmark
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17
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Fleury V, Unbekandt M, Al-Kilani A, Nguyen TH. The Textural Aspects of Vessel Formation during Embryo Development and Their Relation to Gastrulation Movements. Organogenesis 2012; 3:49-56. [PMID: 19279700 DOI: 10.4161/org.3.1.3238] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
We have investigated the microscopic physical inhomogeneity ("texture") of the avian embryo in vivo by shadowgraph. This noninvasive technique allows one to correlate the shape of blood vessels to the physical, micro-structural, pattern that exists in the embryo prior to vessel appearance. Before any vessel forms, vascular paths are present and are prepatterned, by fields of cellular orientations and lumen anisotropies. We find the origin of this prepattern in the movements of the embryo during gastrulation, and the related deformation and force field, which establish both the animal and vascular pattern.
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Affiliation(s)
- Vincent Fleury
- Groupe de Matière Condensée et Matériaux/CNRS; Université de Rennes 1; Rennes France
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18
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De Spiegelaere W, Casteleyn C, Van den Broeck W, Plendl J, Bahramsoltani M, Simoens P, Djonov V, Cornillie P. Intussusceptive Angiogenesis: A Biologically Relevant Form of Angiogenesis. J Vasc Res 2012; 49:390-404. [DOI: 10.1159/000338278] [Citation(s) in RCA: 123] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Accepted: 03/13/2012] [Indexed: 12/11/2022] Open
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Freund JB, Goetz JG, Hill KL, Vermot J. Fluid flows and forces in development: functions, features and biophysical principles. Development 2012; 139:1229-45. [PMID: 22395739 DOI: 10.1242/dev.073593] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Throughout morphogenesis, cells experience intracellular tensile and contractile forces on microscopic scales. Cells also experience extracellular forces, such as static forces mediated by the extracellular matrix and forces resulting from microscopic fluid flow. Although the biological ramifications of static forces have received much attention, little is known about the roles of fluid flows and forces during embryogenesis. Here, we focus on the microfluidic forces generated by cilia-driven fluid flow and heart-driven hemodynamics, as well as on the signaling pathways involved in flow sensing. We discuss recent studies that describe the functions and the biomechanical features of these fluid flows. These insights suggest that biological flow determines many aspects of cell behavior and identity through a specific set of physical stimuli and signaling pathways.
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21
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Effects of convective transport on chemical signal propagation in epithelia. Biophys J 2012; 102:990-1000. [PMID: 22404921 DOI: 10.1016/j.bpj.2012.01.038] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2011] [Revised: 01/13/2012] [Accepted: 01/23/2012] [Indexed: 11/20/2022] Open
Abstract
We study effects of convective transport on a chemical front wave representing a signal propagation at a simple (single layer) epithelium by means of mathematical modeling. Plug flow and laminar flow regimes were considered. We observed a nonmonotonous dependence of the propagation velocity on the ligand receptor binding constant under influence of the convective transport. If the signal propagates downstream, the region of high velocities becomes much broader and spreads over several orders of magnitude of the binding constant. When the convective transport is oriented against the propagating signal, either velocity of the traveling front wave is slowed down or the traveling front wave can stop or reverse the direction of propagation. More importantly, chemical signal in epithelial systems influenced by the convective transport can propagate almost independently of the ligand-receptor binding constant in a broad range of this parameter. Furthermore, we found that the effects of the convective transport becomes more significant in systems where either the characteristic dimension of the extracellular space is larger/comparable with the spatial extent of the ligand diffusion trafficking or the ligand-receptor binding/ligand diffusion rate ratio is high.
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22
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Geudens I, Gerhardt H. Coordinating cell behaviour during blood vessel formation. Development 2011; 138:4569-83. [PMID: 21965610 DOI: 10.1242/dev.062323] [Citation(s) in RCA: 259] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The correct development of blood vessels is crucial for all aspects of tissue growth and physiology in vertebrates. The formation of an elaborate hierarchically branched network of endothelial tubes, through either angiogenesis or vasculogenesis, relies on a series of coordinated morphogenic events, but how individual endothelial cells adopt specific phenotypes and how they coordinate their behaviour during vascular patterning is unclear. Recent progress in our understanding of blood vessel formation has been driven by advanced imaging techniques and detailed analyses that have used a combination of powerful in vitro, in vivo and in silico model systems. Here, we summarise these models and discuss their advantages and disadvantages. We then review the different stages of blood vessel development, highlighting the cellular mechanisms and molecular players involved at each step and focusing on cell specification and coordination within the network.
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Affiliation(s)
- Ilse Geudens
- Vascular Patterning Laboratory, Vesalius Research Center, VIB, 3000 Leuven, Belgium
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23
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Pouteau S, Albertini C. An assessment of morphogenetic fluctuation during reproductive phase change in Arabidopsis. ANNALS OF BOTANY 2011; 107:1017-27. [PMID: 21367754 PMCID: PMC3080622 DOI: 10.1093/aob/mcr039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
BACKGROUND AND AIMS Reproductive phase change in Arabidopsis thaliana is characterized by two transitions in phytomer identity, the differentiation of the first elongate internode (bolting transition) and of the first flower (floral transition). An evaluation of the dynamics of these transitions was sought by examining the precision of the corresponding phytomer identity changes. METHODS The length of the first elongate internode and the frequency of chimeric inflorescence structures, e.g. paraclades not subtended by a leaf (no-leaf/paraclades) and flowers subtended by a bract (bract/flowers), were measured in the Wassilewskija (Ws) accession and 47 early flowering mutants under a wide range of photoperiods. The impact of photoperiodic perturbations applied to Ws plants at different times of development was also evaluated. KEY RESULTS In Ws, both types of characters were remarkably constant across photoperiods in spite of a high degree of interindividual variability. Bract/flowers were not normally produced in Ws, but they were observed in conditions that suggest enhanced light signalling, e.g. in response to continuous light perturbations and in mutants with reduced hypocotyl elongation. In contrast, no-leaf/paraclades were normally present in approx. 20 % of Ws plants, and their frequency was increased in conditions that suggest reduced light signalling, e.g. in mutants with altered specification of long-day responses. The length of the first elongate internode was unrelated to the rate of stem elongation and to the regulation of reproductive phase change. CONCLUSIONS Bract/flowers and no-leaf/paraclades corresponded to opposite effects on the floral transition that reflected different dynamics of progression to flowering. In contrast, the length of the first elongate internode was only indirectly related to the regulation of reproductive phase change and was mainly dependent on global morphogenetic constraints. This paper proposes that morphogenetic variability could be used to identify critical phases of development and characterize the canalization of developmental patterns.
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Affiliation(s)
- Sylvie Pouteau
- Institut Jean-Pierre Bourgin, Institut National de la Recherche Agronomique, RD 10, Versailles, France.
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24
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Lee GS, Filipovic N, Lin M, Gibney BC, Simpson DC, Konerding MA, Tsuda A, Mentzer SJ. Intravascular pillars and pruning in the extraembryonic vessels of chick embryos. Dev Dyn 2011; 240:1335-43. [PMID: 21448976 DOI: 10.1002/dvdy.22618] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/13/2010] [Indexed: 11/07/2022] Open
Abstract
To investigate the local mechanical forces associated with intravascular pillars and vessel pruning, we studied the conducting vessels in the extraembryonic circulation of the chick embryo. During the development days 13-17, intravascular pillars and blood flow parameters were identified using fluorescent vascular tracers and digital time-series video reconstructions. The geometry of selected vessels was confirmed by corrosion casting and scanning electron microscopy. Computational simulations of pruning vessels suggested that serial pillars form along pre-existing velocity streamlines; blood pressure demonstrated no obvious spatial relationship with the intravascular pillars. Modeling a Reynolds number of 0.03 produced 4 pillars at approximately 20-μm intervals matching the observed periodicity. In contrast, a Reynolds number of 0.06 produced only 2 pillars at approximately 63-μm intervals. Our modeling data indicated that the combination of wall shear stress and gradient of shear predicted the location, direction, and periodicity of developing pillars.
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Affiliation(s)
- Grace S Lee
- Laboratory of Adaptive and Regenerative Biology, Brigham & Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
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25
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Lorthois S, Cassot F, Lauwers F. Simulation study of brain blood flow regulation by intra-cortical arterioles in an anatomically accurate large human vascular network. Part II: flow variations induced by global or localized modifications of arteriolar diameters. Neuroimage 2010; 54:2840-53. [PMID: 21047557 DOI: 10.1016/j.neuroimage.2010.10.040] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2010] [Revised: 09/29/2010] [Accepted: 10/12/2010] [Indexed: 01/26/2023] Open
Abstract
In a companion paper (Lorthois et al., Neuroimage, in press), we perform the first simulations of blood flow in an anatomically accurate large human intra-cortical vascular network (~10000 segments), using a 1D non-linear model taking into account the complex rheological properties of blood flow in microcirculation. This model predicts blood pressure, blood flow and hematocrit distributions, volumes of functional vascular territories, regional flow at voxel and network scales, etc. Using the same approach, we study flow reorganizations induced by global arteriolar vasodilations (an isometabolic global increase in cerebral blood flow). For small to moderate global vasodilations, the relationship between changes in volume and changes in flow is in close agreement with Grubb's law, providing a quantitative tool for studying the variations of its exponent with underlying vascular architecture. A significant correlation between blood flow and vascular structure at the voxel scale, practically unchanged with respect to baseline, is demonstrated. Furthermore, the effects of localized arteriolar vasodilations, representative of a local increase in metabolic demand, are analyzed. In particular, localized vasodilations induce flow changes, including vascular steal, in the neighboring arteriolar trunks at small distances (<300 μm), while their influence in the neighboring veins is much larger (about 1 mm), which provides an estimate of the vascular point spread function. More generally, for the first time, the hemodynamic component of various functional neuroimaging techniques has been isolated from metabolic and neuronal components, and a direct relationship with several known characteristics of the BOLD signal has been demonstrated.
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Affiliation(s)
- S Lorthois
- Institut de Mécanique des Fluides de Toulouse, UMR CNRS/INP/UPS 5502, Toulouse, France.
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26
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Jones EAV. Mechanotransduction and blood fluid dynamics in developing blood vessels. CAN J CHEM ENG 2010. [DOI: 10.1002/cjce.20290] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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27
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Fleury V, Al-Kilani A, Boryskina OP, Cornelissen AJM, Nguyen TH, Unbekandt M, Leroy L, Baffet G, le Noble F, Sire O, Lahaye E, Burgaud V. Introducing the scanning air puff tonometer for biological studies. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2010; 81:021920. [PMID: 20365608 DOI: 10.1103/physreve.81.021920] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2009] [Revised: 11/10/2009] [Indexed: 05/29/2023]
Abstract
It is getting increasingly evident that physical properties such as elastoviscoplastic properties of living materials are quite important for the process of tissue development, including regulation of genetic pathways. Measuring such properties in vivo is a complicated and challenging task. In this paper, we present an instrument, a scanning air puff tonometer, which is able to map point by point the viscoelastic properties of flat or gently curved soft materials. This instrument is an improved version of the air puff tonometer used by optometrists, with important modifications. The instrument allows one to obtain a direct insight into gradients of material properties in vivo. The instrument capabilities are demonstrated on substances with known elastoviscoplastic properties and several biological objects. On the basis of the results obtained, the role of the gradients of elastoviscoplastic properties is outlined for the process of angiogenesis, limb development, bacterial colonies expansion, etc. which is important for bridging the gaps in the theory of the tissue development and highlighting new possibilities for tissue engineering, based on a clarification of the role of physical features in developing biological material.
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Affiliation(s)
- Vincent Fleury
- Laboratoire Matière et Systèmes Complexes, UMR 7057, Université Paris-Diderot, CNRS, Bâtiment Condorcet, 10 Rue Alice Domon et Léonie Duquet, 75013 Paris, France
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28
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Fractal analysis of vascular networks: Insights from morphogenesis. J Theor Biol 2010; 262:614-33. [DOI: 10.1016/j.jtbi.2009.10.037] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2009] [Revised: 10/20/2009] [Accepted: 10/29/2009] [Indexed: 11/17/2022]
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29
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Ellertsdóttir E, Lenard A, Blum Y, Krudewig A, Herwig L, Affolter M, Belting HG. Vascular morphogenesis in the zebrafish embryo. Dev Biol 2009; 341:56-65. [PMID: 19895803 DOI: 10.1016/j.ydbio.2009.10.035] [Citation(s) in RCA: 142] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2009] [Revised: 10/28/2009] [Accepted: 10/28/2009] [Indexed: 12/31/2022]
Abstract
During embryonic development, the vertebrate vasculature is undergoing vast growth and remodeling. Blood vessels can be formed by a wide spectrum of different morphogenetic mechanisms, such as budding, cord hollowing, cell hollowing, cell wrapping and intussusception. Here, we describe the vascular morphogenesis that occurs in the early zebrafish embryo. We discuss the diversity of morphogenetic mechanisms that contribute to vessel assembly, angiogenic sprouting and tube formation in different blood vessels and how some of these complex cell behaviors are regulated by molecular pathways.
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Affiliation(s)
- Elín Ellertsdóttir
- Department of Cell Biology, Biozentrum der Universität Basel, Klingelbergstrasse 70, CH-4056 Basel, Switzerland
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Corson F, Adda-Bedia M, Boudaoud A. In silico leaf venation networks: growth and reorganization driven by mechanical forces. J Theor Biol 2009; 259:440-8. [PMID: 19446571 DOI: 10.1016/j.jtbi.2009.05.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2008] [Revised: 05/05/2009] [Accepted: 05/05/2009] [Indexed: 11/25/2022]
Abstract
Development commonly involves an interplay between signaling, genetic expression and biophysical forces. However, the relative importance of these mechanisms during the different stages of development is unclear. Leaf venation networks provide a fitting context for the examination of these questions. In mature leaves, venation patterns are extremely diverse, yet their local structure satisfies a universal property: at junctions between veins, angles and diameters are related by a vectorial equation analogous to a force balance. Using a cell proliferation model, we reproduce in silico the salient features of venation patterns. Provided that vein cells are given different mechanical properties, tensile forces develop along the veins during growth, causing the network to deform progressively. Our results suggest that the local structure of venation networks results from a reorganization driven by mechanical forces, independently of how veins form. This conclusion is supported by recent observations of vein development in young leaves and by the good quantitative agreement between our simulations and data from mature leaves.
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Affiliation(s)
- Francis Corson
- Laboratoire de Physique Statistique, Ecole Normale Supérieure, UPMC Paris 06, Université Paris Diderot, CNRS, 24 rue Lhomond, 75005 Paris, France.
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Al-Kilani A, Lorthois S, Nguyen TH, Le Noble F, Cornelissen A, Unbekandt M, Boryskina O, Leroy L, Fleury V. During vertebrate development, arteries exert a morphological control over the venous pattern through physical factors. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2008; 77:051912. [PMID: 18643107 DOI: 10.1103/physreve.77.051912] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2007] [Indexed: 05/26/2023]
Abstract
The adult vasculature is comprised of three distinct compartments: the arteries, which carry blood away from the heart and display a divergent flow pattern; the capillaries, where oxygen and nutrient delivery from blood to tissues, as well as metabolic waste removal, occurs; and the veins, which carry blood back to the heart and are characterized by a convergent flow pattern. These compartments are organized in series as regard to flow, which proceeds from the upstream arteries to the downstream veins through the capillaries. However, the spatial organization is more complex, as veins may often be found paralleling the arteries. The factors that control the morphogenesis of this hierarchically branched vascular network are not well characterized. Here, we explain how arteries exert a morphological control on the venous pattern. Indeed, during vertebrate development, the following transition may be observed in the spatial organization of the vascular system: veins first develop in series with the arteries, the arterial and venous territories being clearly distinct in space (cis-cis configuration). But after some time, new veins grow parallel to the existing arteries, and the arterial and venous territories become overlapped, with extensive and complex intercalation and interdigitation. Using physical arguments, backed up by experimental evidence (biological data from the literature and in situ optical and mechanical measurements of the chick embryo yolk-sac and midbrain developing vasculatures), we explain how such a transition is possible and why it may be expected with generality, as organisms grow. The origin of this transition lies in the remodeling of the capillary tissue in the vicinity of the growing arteries. This remodeling lays down a prepattern for further venous growth, parallel to the existing arterial pattern. Accounting for the influence of tissue growth, we show that this prepatterned path becomes favored as the body extends. As a consequence, a second flow route with veins paralleling the arteries (cis-trans configuration) emerges when the tissue extends. Between the cis-cis and cis-trans configurations, all configurations are in principle possible, and self-organization of the vessels contributes to determining their exact pattern. However, the global aspect depends on the size at which the growth stops and on the growth rate.
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Affiliation(s)
- Alia Al-Kilani
- Groupe Matière Condensée et Matériaux, Université de Rennes 1, Campus de Beaulieu, Bâtiment 13A, 35 042 Rennes, France
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Jakobsson L, Kreuger J, Claesson-Welsh L. Building blood vessels--stem cell models in vascular biology. ACTA ACUST UNITED AC 2007; 177:751-5. [PMID: 17535968 PMCID: PMC2064276 DOI: 10.1083/jcb.200701146] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Spheroids of differentiating embryonic stem cells, denoted embryoid bodies, constitute a high-quality model for vascular development, particularly well suited for loss-of-function analysis of genes required for early embryogenesis. This review examines vasculogenesis and angiogenesis in murine embryoid bodies and discusses the promise of stem cell–based models for the study of human vascular development.
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Affiliation(s)
- Lars Jakobsson
- Department of Genetics and Pathology, Uppsala University, SE-751 85 Uppsala, Sweden
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33
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Use of Prelaminated Free Forearm Flap with Tissue Expansion in Reconstruction. Plast Reconstr Surg 2007. [DOI: 10.1097/01.prs.0000229183.53712.b7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Nagase T, Nagase M, Machida M, Yamagishi M. Hedgehog signaling: a biophysical or biomechanical modulator in embryonic development? Ann N Y Acad Sci 2007; 1101:412-38. [PMID: 17332081 DOI: 10.1196/annals.1389.029] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Although embryonic development is inevitably affected by biophysical or biomechanical processes, it has yet to be elucidated to what extent molecular mechanisms of development are modulated by such physical factors. The hedgehog family, including Sonic hedgehog (Shh), is the most well-known morphogens involved in the developmental pattern formation of various organs, such as the nervous system, face, limbs, and skin appendages. There are several unique features in hedgehog signaling including long-range diffusion or positive and negative feedback loops, suggesting the possible modification of hedgehog signaling by biophysical or biomechanical factors. Especially, the period of embryonic day 8-10 is characterized by various biomechanically regulated processes in mouse development, such as axial rotation and vasculoangiogenesis. We executed a series of experiments using a mouse whole embryo culture system to investigate the biomechanical roles of hedgehog signaling during this period. In this review, we examine various examples in which biophysical and biomechanical aspects of hedgehog signaling in development are revealed, including our own data using the mouse whole embryo culture system.
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Affiliation(s)
- Takashi Nagase
- Clinical Research Center, National Hospital Organization Murayama Medical Center, 2-37-1 Gakuen, Musashimurayama-shi, Tokyo 208-0011, Japan.
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Jones EAV, le Noble F, Eichmann A. What Determines Blood Vessel Structure? Genetic Prespecification vs. Hemodynamics. Physiology (Bethesda) 2006; 21:388-95. [PMID: 17119151 DOI: 10.1152/physiol.00020.2006] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Vascular network remodeling, angiogenesis, and arteriogenesis play an important role in the pathophysiology of ischemic cardiovascular diseases and cancer. Based on recent studies of vascular network development in the embryo, several novel aspects to angiogenesis have been identified as crucial to generate a functional vascular network. These aspects include specification of arterial and venous identity in vessels and network patterning. In early embryogenesis, vessel identity and positioning are genetically hardwired and involve neural guidance genes expressed in the vascular system. We demonstrated that, during later stages of embryogenesis, blood flow plays a crucial role in regulating vessel identity and network remodeling. The flow-evoked remodeling process is dynamic and involves a high degree of vessel plasticity. The open question in the field is how genetically predetermined processes in vessel identity and patterning balance with the contribution of blood flow in shaping a functional vascular architecture. Although blood flow is essential, it remains unclear to what extent flow is able to act on the developing cardiovascular system. There is significant evidence that mechanical forces created by flowing blood are biologically active within the embryo and that the level of mechanical forces and the type of flow patterns present in the embryo are able to affect gene expression. Here, we highlight the pivotal role for blood flow and physical forces in shaping the cardiovascular system.
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