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BioEssays : News and Reviews in... Mar 2014The establishment of a functional vascular system requires multiple complex steps throughout embryogenesis, from endothelial cell (EC) specification to vascular... (Review)
Review
The establishment of a functional vascular system requires multiple complex steps throughout embryogenesis, from endothelial cell (EC) specification to vascular patterning into venous and arterial hierarchies. Following the initial assembly of ECs into a network of cord-like structures, vascular expansion and remodeling occur rapidly through morphogenetic events including vessel sprouting, fusion, and pruning. In addition, vascular morphogenesis encompasses the process of lumen formation, critical for the transformation of cords into perfusable vascular tubes. Studies in mouse, zebrafish, frog, and human endothelial cells have begun to outline the cellular and molecular requirements underlying lumen formation. Although the lumen can be generated through diverse mechanisms, the coordinated participation of multiple conserved molecules including transcription factors, small GTPases, and adhesion and polarity proteins remains a fundamental principle, leading us closer to a more thorough understanding of this complex event.
Topics: Animals; Blood Vessels; Cell Polarity; Cytoskeleton; Endothelial Cells; Humans; Monomeric GTP-Binding Proteins; Organogenesis
PubMed: 24323945
DOI: 10.1002/bies.201300133 -
Angiogenesis 2009Infantile hemangioma is a vascular tumor that occurs in 5-10% of infants of European descent. A defining feature of infantile hemangioma is the dramatic growth and... (Review)
Review
Infantile hemangioma is a vascular tumor that occurs in 5-10% of infants of European descent. A defining feature of infantile hemangioma is the dramatic growth and development into a disorganized mass of blood vessels. Subsequently, a slow spontaneous involution begins around 1 year of age and continues for 4-6 years. The growth and involution of infantile hemangioma is very different from other vascular tumors and vascular malformations, which do not regress and can occur at any time during childhood or adult life. Much has been learned from careful study of the tissue morphology and gene expression patterns during the life-cycle of hemangioma. Tissue explants and tumor-derived cell populations have provided further insight to unravel the cellular and molecular basis of infantile hemangioma. A multipotent progenitor cell capable of de novo blood vessel formation has been isolated from infantile hemangioma, which suggests that this common tumor of infancy, long considered to be a model for pathologic angiogenesis, may also represent pathologic vasculogenesis. Whether viewed as angiogenesis or vasculogenesis, infantile hemangioma represents a vascular perturbation during a critical period of post-natal growth, and as such provides a unique opportunity to decipher mechanisms of human vascular development.
Topics: Blood Vessels; Hemangioma; Humans; Infant; Morphogenesis; Multipotent Stem Cells
PubMed: 19430954
DOI: 10.1007/s10456-009-9148-2 -
Biotechnology Journal Apr 2013Vascular engineering seeks to design and construct functional blood vessels comprising endothelial cells (ECs) and perivascular cells (PCs), with the ultimate goal of... (Review)
Review
Vascular engineering seeks to design and construct functional blood vessels comprising endothelial cells (ECs) and perivascular cells (PCs), with the ultimate goal of clinical translation. While EC behavior has been extensively investigated, PCs play an equally significant role in the development of novel regenerative strategies, providing functionality and stability to vessels. The two major classes of PCs are vascular smooth muscle cells (vSMCs) and pericytes; vSMCs can be further sub-classified as either contractile or synthetic. The inclusion of these cell types is crucial for successful regeneration of blood vessels. Furthermore, understanding distinctions between vSMCs and pericytes will enable improved therapeutics in a tissue-specific manner. Here we focus on the approaches and challenges facing the use of PCs in vascular regeneration, including their characteristics, stem cell sources, and interactions with ECs. Finally, we discuss biochemical and microRNA (miR) regulators of PC behavior and engineering approaches that mimic various cues affecting PC function.
Topics: Animals; Humans; Muscle, Smooth, Vascular; Pericytes; Regeneration; Tissue Engineering
PubMed: 23554249
DOI: 10.1002/biot.201200199 -
Cold Spring Harbor Perspectives in... Feb 2018Over the past 40 years, remarkable advances have been made in our understanding of successful blood vessel regeneration, starting with the failures of early... (Review)
Review
Over the past 40 years, remarkable advances have been made in our understanding of successful blood vessel regeneration, starting with the failures of early tissue-engineered vascular grafts designed using isolated components or molecules, such as collagen gels. The vascular tissue engineers are today better educated and have steered ongoing research developments toward clinical developments of more complete vascular grafts that replicate the multitude of specialized arterial aspects required for function.
Topics: Allografts; Animals; Blood Vessel Prosthesis; Blood Vessels; Heterografts; Humans; Tissue Engineering; Tissue Scaffolds
PubMed: 28348177
DOI: 10.1101/cshperspect.a025742 -
Nature Apr 2016Bone marrow endothelial cells (BMECs) form a network of blood vessels that regulate both leukocyte trafficking and haematopoietic stem and progenitor cell (HSPC)...
Bone marrow endothelial cells (BMECs) form a network of blood vessels that regulate both leukocyte trafficking and haematopoietic stem and progenitor cell (HSPC) maintenance. However, it is not clear how BMECs balance these dual roles, and whether these events occur at the same vascular site. We found that mammalian bone marrow stem cell maintenance and leukocyte trafficking are regulated by distinct blood vessel types with different permeability properties. Less permeable arterial blood vessels maintain haematopoietic stem cells in a low reactive oxygen species (ROS) state, whereas the more permeable sinusoids promote HSPC activation and are the exclusive site for immature and mature leukocyte trafficking to and from the bone marrow. A functional consequence of high permeability of blood vessels is that exposure to blood plasma increases bone marrow HSPC ROS levels, augmenting their migration and differentiation, while compromising their long-term repopulation and survival. These findings may have relevance for clinical haematopoietic stem cell transplantation and mobilization protocols.
Topics: Animals; Antigens, Ly; Arteries; Blood Vessels; Bone Marrow; Bone Marrow Cells; Cell Differentiation; Cell Movement; Cell Self Renewal; Cell Survival; Chemokine CXCL12; Endothelial Cells; Female; Hematopoiesis; Hematopoietic Stem Cell Mobilization; Hematopoietic Stem Cell Transplantation; Hematopoietic Stem Cells; Leukocytes; Male; Membrane Proteins; Mice; Mice, Inbred C57BL; Nestin; Pericytes; Permeability; Plasma; Reactive Oxygen Species; Receptors, CXCR4
PubMed: 27074509
DOI: 10.1038/nature17624 -
EMBO Molecular Medicine Mar 2018The blood vasculature is an organ pervading all other organs (almost). During vascular development, cell-cell signaling by extracellular ligands and cell surface...
The blood vasculature is an organ pervading all other organs (almost). During vascular development, cell-cell signaling by extracellular ligands and cell surface receptors ensure that new vessels sprout into non-vascularized regions and simultaneously acquire organ-specific specializations and adaptations that match the local physiological needs. The vessels thereby specialize in their permeability, molecular transport between blood and tissue, and ability to regulate blood flow on demand. Over the past decades, we have learnt about the generic cell-cell signaling mechanisms governing angiogenic sprouting, mural cell recruitment, and vascular remodeling, and we have obtained the first insights into signals that induce and maintain vascular organotypicity. However, intra-organ vascular diversity and arterio-venous hierarchies complicate the molecular characterization of the vasculature's cellular building blocks. Single-cell RNA sequencing provides a way forward, as it allows elucidation at a genome-wide and quantitative level of the transcriptional diversity occurring within the same cell types at different anatomical positions and levels of arterio-venous hierarchy in the organs. In this , I give a brief overview of vascular development and how recent advances in the field pave the way for more systematic efforts to explore vascular functions in health and disease.
Topics: Animals; Blood Vessels; Cell Communication; Endothelial Cells; Humans; Models, Biological; Neovascularization, Physiologic; Signal Transduction
PubMed: 29363489
DOI: 10.15252/emmm.201708610 -
Vascular Health and Risk Management 2005
Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Aortic Aneurysm, Abdominal; Blood Vessels; Cardiovascular Diseases; Compliance; Eicosanoids; Extracellular Matrix; Humans; Risk Assessment; Risk Factors
PubMed: 17315393
DOI: 10.2147/vhrm.1.2.91.64081 -
Vascular Health and Risk Management 2015An ideal vascular substitute, especially in <6 mm diameter applications, is a major clinical essentiality in blood vessel replacement surgery. Blood vessels are... (Review)
Review
An ideal vascular substitute, especially in <6 mm diameter applications, is a major clinical essentiality in blood vessel replacement surgery. Blood vessels are structurally complex and functionally dynamic tissue, with minimal regeneration potential. These have composite extracellular matrix (ECM) and arrangement. The interplay between ECM components and tissue specific cells gives blood vessels their specialized functional attributes. The core of vascular tissue engineering and regeneration relies on the challenges in creating vascular conduits that match native vessels and adequately regenerate in vivo. Out of numerous vascular regeneration concerns, the relevance of ECM emphasizes much attention toward appropriate choice of scaffold material and further scaffold development strategies. The review is intended to be focused on the various approaches of scaffold materials currently in use in vascular regeneration and current state of the art. Scaffold of choice in vascular tissue engineering ranges from natural to synthetic, decellularized, and even scaffold free approach. The applicability of tubular scaffold for in vivo vascular regeneration is under active investigation. A patent conduit with an ample endothelial luminal layer that can regenerate in vivo remains an unanswered query in the field of small diameter vascular tissue engineering. Besides, scaffolds developed for vascular regeneration, should aim at providing functional substitutes for use in a regenerative approach from the laboratory bench to patient bedside.
Topics: Animals; Bioprosthesis; Blood Vessel Prosthesis; Blood Vessel Prosthesis Implantation; Blood Vessels; Cell Differentiation; Cell Proliferation; Extracellular Matrix; Humans; Polymers; Prosthesis Design; Regeneration; Regenerative Medicine; Tissue Engineering; Tissue Scaffolds
PubMed: 25632236
DOI: 10.2147/VHRM.S50536 -
The Journal of Physiology Mar 2017Astrocytes are the most common glial cells in the brain with fine processes and endfeet that intimately contact both neuronal synapses and the cerebral vasculature. They... (Review)
Review
Astrocytes are the most common glial cells in the brain with fine processes and endfeet that intimately contact both neuronal synapses and the cerebral vasculature. They play an important role in mediating neurovascular coupling (NVC) via several astrocytic Ca -dependent signalling pathways such as K release through B channels, and the production and release of arachidonic acid metabolites. They are also involved in maintaining the resting tone of the cerebral vessels by releasing ATP and COX-1 derivatives. Evidence also supports a role for astrocytes in maintaining blood pressure-dependent change in cerebrovascular tone, and perhaps also in blood vessel-to-neuron signalling as posited by the 'hemo-neural hypothesis'. Thus, astrocytes are emerging as new stars in preserving the intricate balance between the high energy demand of active neurons and the supply of oxygen and nutrients from the blood by maintaining both resting blood flow and activity-evoked changes therein. Following neuropathology, astrocytes become reactive and many of their key signalling mechanisms are altered, including those involved in NVC. Furthermore, as they can respond to changes in vascular pressure, cardiovascular diseases might exert previously unknown effects on the central nervous system by altering astrocyte function. This review discusses the role of astrocytes in neurovascular signalling in both physiology and pathology, and the impact of these findings on understanding BOLD-fMRI signals.
Topics: Animals; Astrocytes; Blood Vessels; Brain; Humans; Neurovascular Coupling; Synapses
PubMed: 27619153
DOI: 10.1113/JP270979 -
Cold Spring Harbor Perspectives in... Sep 2012VEGF-A signaling is required for almost every aspect of vascular development, and it is a major regulator of vessel morphogenesis and patterning. VEGF-A perturbations... (Review)
Review
VEGF-A signaling is required for almost every aspect of vascular development, and it is a major regulator of vessel morphogenesis and patterning. VEGF-A perturbations are associated with severe vascular defects and lethality, and the pathway is coopted in pathological scenarios, including tumor angiogenesis. This review focuses on the roles of VEGF-A signaling during vessel development and patterning. I review the impact of VEGF-A signaling on endothelial cells in developing vessels, with emphasis on the importance of spatial regulation of several pathway components. I also discuss VEGF-A signaling patterns at the level of the vessel, with a focus on how polarity is set up and maintained in several vessel axes. The role of VEGF-A in patterning vessels relative to tissues and organs is also reviewed, with emphasis on neurovascular patterning and patterning at the embryonic midline.
Topics: Alternative Splicing; Animals; Blood Vessels; Cell Polarity; Endothelial Cells; Endothelium, Vascular; Humans; Neovascularization, Physiologic; Signal Transduction; Vascular Endothelial Growth Factor A
PubMed: 22951440
DOI: 10.1101/cshperspect.a006452