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Solid tumors: biochemical overview and mechanical modeling
Published in Benjamin Loret, Fernando M. F. Simões, Biomechanical Aspects of Soft Tissues, 2017
Benjamin Loret, Fernando M. F. Simões
Blood vessels form by two mechanisms, vasculogenesis and angiogenesis. Vasculogenesis is mainly active during embryonic life and involves the creation of vessels from scratch, in which undifferentiated cells elongate to form a tube: on the outer part, the cells transform to smooth muscle while the inner part becomes blood cells. The differentiation of the wall of the vessels increases in time to form, from inside to outside, the intima, media and adventitia, Fung [1993], p. 322. The intima is mainly composed of endothelial cells, the media of smooth muscles and collagen fibrils and the adventitia of collagen fibers, vasa vasorum24.5 (capillaries, arterioles, venulas), and nerves. Veins have the same layered structure as arteries although the wall is thinner and the composition slightly different in accordance with their hemodynamic function. For a detailed histology of the blood vessels and of the lymphatic network, the reader may consult Dadoune et al. [2000].
First Therapeutic Aptamer: VEGF-Targeting Macugen
Published in Rakesh N. Veedu, Aptamers, 2017
Nicholas Leonard, Xiaoting Zhang
VEGF (also known as VEGF-A) is a member of a growth factor gene family that also includes VEGF-B, VEFG-C, VEGF-D, and placental growth factor (PGF). VEGFs are the key signaling proteins involved in both de novo vasculogenesis and angiogenesis from preexisting vasculature. The major activity of VEGF in promoting angiogenesis is through stimulating the proliferation of vascular endothelial cells (ECs) and preventing ECs from apoptosis [16]. In addition, VEGF plays important roles in vascular permeability and induces tumor-and disease-driving vascular leakage [13, 32]. As mentioned earlier, this VEGF-induced vascular leakage is a significant contributor to the progression of the dry AMD to the more severe wet form of the disease.
Principles and Biological Pathways to Tissue Regeneration: The Tissue Regenerative Niche
Published in Claudio Migliaresi, Antonella Motta, Scaffolds for Tissue Engineering, 2014
Ranieri Cancedda, Claudia Lo Sicco
In a regenerative microenvironment, both angiogenesis and vasculogenesis occur [Madeddu, 2005]. Many of the angiogenic factors that stimulate proliferation and sprouting of endothelial cells are also involved in the recruitment of circulating, bone marrow derived endothelial cell progenitors. Factors such as the stem cell factor (SCF or sKitL) and enzymatic activities such as the matrix metalloproteinase-9 (MMP-9) certainly play an important role in the vasculogenesis process. Unfortunately, molecular and cellular mechanisms that control vasculogenesis are only partially known.
Embryotoxic effects of Rovral® for early chicken (Gallus gallus) development
Published in Journal of Toxicology and Environmental Health, Part A, 2021
Beatriz Mitidiero Stachissini Arcain, Maria Cláudia Gross, Danúbia Frasson Furtado, Carla Vermeulen Carvalho Grade
Several embryos treated with Rovral® presented hemorrhages on both sides of the body, as well as in organs and head. During development, blood vessels are formed by the processes of vasculogenesis, in which new vessels are formed from precursor cells, and angiogenesis, in which new vessels are formed from preexisting vessels, through budding and branching (Cox and Poole 2000; DeSesso 2017; Eichmann et al. 2002; Gilbert and Barresi 2016; Moore, Persaud, and Torchia 2016). Damage to blood vessels that initiates bleeding may be the result of alterations in cell junctions, viability and migration of endothelial cells (Lu et al. 2016), as well as endothelial defects (Canault et al. 2010). Contamination with pesticides might lead to a weakening of the vessels at the time of their formation, which results in rupture, generating hemorrhages, as noted in several studies (Goyal, Sandhu, and Brar 2010; Pamanji et al. 2015; Roopadevi et al. 2012; Sarty, Cowie, and Martyniuk 2017; Zhu et al. 2019), which might lead to high mortality rates. In the present study, bleeding was found both in live embryos (n = 2), but especially in dead embryos (n = 14) treated with Rovral®, which may have died due to the observed bleeding.
Different influence of sulfated chitosan with different sulfonic acid group sites on HUVECs behaviors
Published in Journal of Biomaterials Science, Polymer Edition, 2020
Guijuan Han, Xiaohui Xia, Zhicheng Pan, Yucheng Lin, Lihua Li, Yanpeng Jiao, Changren Zhou, Shan Ding
HUVEC cells protein expression contents affected by different SCS and heparin were tested by Western blot, including the CD31, vWF and VEGF. As showed in Figure 9, all bands of each group became darker with the culture time prolonged, which indicated the protein expressions content was increased. Moreover, the 2,6-SCS group had higher protein expression compared with others. This result was consistent with the results of gene expression and correlated tests. CD31, platelet endothelial cell adhesion molecule1 [43], is a cell adhesion molecule with proangiogenic and proinflammatory activity. CD31 not only plays a role as an adhesion molecule but also participates in intracellular signaling pathways which have an impact on various cell adhesive mechanisms and endothelial nitric oxide synthase (eNOS) expression and activity [44]. VWF, a glycoprotein expressed by endothelial cells and megakaryocytes, is usually applied to identify vessels in tissue sections [45], and is important protein for angiogenesis regulation. VEGF is a potential trigger for angiogenesis [46], and it can induces endothelial cell proliferation, promotes cell migration and inhibits apoptosis. In vivo VEGF induces angiogenesis as well as permeabilization of blood vessels and plays a central role in the regulation of vasculogenesis [47]. The 2,6-SCS stimulated endogenous CD31, vWF and VEGF high expressed than other groups, indicating that 2,6-SCS have a higher potential to facilitate angiogenesis than other SCS and heparin.
The analogies between human development and additive manufacture: Expanding the definition of design
Published in Cogent Engineering, 2019
L. E. J. Thomas-Seale, J. C. Kirkman-Brown, S. Kanagalingam, M. M. Attallah, D. M. Espino, D. E. T. Shepherd
Perfusion Manufacturing is derived from an analogy of the motion of fluids in the circulatory system. The growth of tissue in the foetus happens simultaneously with the growth of the vasculature (Harding & Bocking, 2001). Similar to the complex feedback loop seen in the morphogenesis of the heart, section 5.1.1, the perfused fluid in the developing circulatory system, is also carrying the nutrients for growth. The development of the cardiovascular system occurs through vasculogenesis and angiogenesis. Vasculogenesis, the development of new vessels, beginning in the third week of embryogenesis, in response to the requirement for nutrients from the maternal circulation (Moore et al., 2013a). Its physiology is summarized as follows: angioblasts (differentiated from mesenchymal cells) group into clusters called blood islands, the confluence of intercellular clefts result in small cavities in these blood islands, which become lined with angioblasts flattened to form the endothelium, finally these endothelium lined cavities then fuse to form the endothelial channels (Moore et al., 2013a). Angiogenesis, the growth of new vessels from pre-existing vessels, expands the vascular network. Angiogenesis of vessels occurs by budding and sprouting of existing vessels or the intussusception, i.e. the separation or fusion of vessels (Schoenwolf et al., 2015).