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Neuropathology Of Neuro-Ophthalmic Disorders
Published in Vivek Lal, A Clinical Approach to Neuro-Ophthalmic Disorders, 2023
Hemangiomas and vascular malformations are commonly encountered in orbit. Such lesions may compress optic nerve and other intra-orbital structures. Various forms of vascular malformation can involve orbit, such as cavernous hemangioma, capillary hemangioma, arteriovenous malformation (AVM), lymphangioma and venous malformation. The cavernous hemangioma is the commonest orbital lesion seen in adults. It is a well-circumscribed tumor composed of dilated vascular channels which are lined by single layer of endothelial cells and separated by fibrous stroma (Figure 25.12a). If required endothelial cells can be highlighted by immunostaining for CD31 (Figure 25.12b). The walls may contain smooth muscle fibers.
Vitreoretinal Surgery in Rare Conditions
Published in Pradeep Venkatesh, Handbook of Vitreoretinal Surgery, 2023
Retinal angiomas are rare tumours [hamartoma] that develop within the vascular bed of the retina. It may be sporadic or a part of the multisystem disorder, von Hippel Lindau [VHL] syndrome. VHL is inherited as an autosomal dominant disease with high penetrance and variable expressivity; the genetic defect being in the VHL gene located on the short arm of chromosome 3. These tumours express brachyury, FlK-1, and Scl, and so are thought to develop from embryologically arrested mesodermal cells programmed to develop into hemangioblasts. Tie-2 and CD31 endothelial markers have also been detected in these tumours. Other than retinal angiomas, VHL is associated with hemangioblastomas of the central nervous system (mainly infratentorial); renal cell carcinoma; pancreatic carcinoma; pheochromocytoma; and adrenal, pancreatic, and epidydimal cysts. Extraocular lesions could develop over a variable time frame, as late as the fifth decade of life, so periodic screening is recommended in all patients diagnosed with retinal angiomas.
Mast Cell Activation and Leukocyte Recruitment Responses Into Skin Sites
Published in Bruce S. Bochner, Adhesion Molecules in Allergic Disease, 2020
Michael D. Ioffreda, George F. Murphy
Platelet-endothelial cell adhesion molecule-1 (PECAM-1, CD31), a member of the immunoglobulin gene superfamily of CAMs, is expressed on the surface of leukocytes, platelets, and endothelial cells. In cultured endothelial cells that recapitulate a partially activated phenotype, PECAM-1 localizes at inter-endothelial cell junctions (56). Possibly through homophilic adhesion, PECAM-1 may play a role in the passage of neutrophils through the gaps between endothelial cells (57,58). In our laboratory, we have observed resting endothelium in situ to express PECAM-1 circumferentially along the entirety of the endothelial plasma membrane. Endothelium stimulated by TNF-α or mast cell degranulation, however, is characterized by aggregation of PECAM-1 to inter-endothelial junctions where diapedesis is expected to occur (unpublished observations). Such redistribution could establish an “adhesion gradient” that contributes to preferential congregation of loosely bound leukocytes to endothelial cell–cell junctions in preparation for their transmural migration. Muller and colleagues showed that anti-PECAM-1 antibodies blocked the transmigration of leukocytes through TNF-α-activated endothelial monolayers in vitro, and Vaporciyan et al. supported this finding in animal models of neutrophil transmigration (58,59). In vivo experiments using mast cell-deficient mice showed that TNF of mast cell origin was responsible for neutrophil emigration (60).
Inhibition of hypoxia-inducible factor-1 by salidroside in an in vitro model of choroidal neovascularization
Published in Cutaneous and Ocular Toxicology, 2022
Haitao Yang, Qingwu Yang, Linfei Zheng
VEGF is excessively secreted by the RPE layer that forms the outer Blood-Retina Barrier in AMD, and contributes to the stimulation of CNV23,24. Basic fibroblast growth factor (FGF2) was found in the extracellular matrix and in endothelial cells of choroidal neovascular membranes25. In a rat model of laser-induced CNV, increases in FGF2 and VEGF mRNA are seen in RPE-like cells, choroidal vascular endothelial cells, and fibroblast-like cells in the lesions26–28. FGF and VEGF are also present in choroidal neovascular membranes from patients with age-related macular degeneration29. As the target gene of HIF-1, the pro-angiogenic role of FGF in ocular diseases has been widely considered30. Moreover, FGF-2 signalling has been shown to cross-talk with VEGF. Our data demonstrated that endogenous FGF-2 induced the expression of VEGF31. FGF-2 blockage agents have great potential for the treatment of angiogenic disorders. CD31 is an adhesion receptor with several important functions including angiogenesis, transendothelial migration, and integrin activation32. CD31 has been shown to play a pivotal role in the regulation of adhesion-mediated cell growth and the maintenance of vascular permeability as well as integrity33.
Building platelet phenotypes: Diaphanous-related formin 1 (DIAPH1)-related disorder
Published in Platelets, 2022
David Rabbolini, Hai Po Helena Liang, Marie-Christine Morel-Kopp, David Connor, Shane Whittaker, Scott Dunkley, Dea Donikian, Mayuko Kondo, Walter Chen, William S Stevenson, Heather Campbell, Joanne Joseph, Christopher Ward, Timothy Brighton, Vivien M. Chen
Platelet area on fibrinogen-coated surface before and after thrombin stimulation was significantly increased for DIAPH1 patients compared to that of healthy control (Figure 4A-B), confirming that the DIAPH1 R1213X variant resulted in macrothrombocytopenia in both individuals II.1 and III.1. Platelet receptor quantitation by flow cytometry showed increased surface expression of αIIbβ3 (CD41 and CD61) and glycoprotein (GP) Ib-IX (CD42b and CD42a) in both individuals, in keeping with the presence of large platelets (Supplemental Figure 4). A similar increase was noted for expression of the platelet endothelial cell adhesion molecule (PECAM-1, CD31) (Supplemental Figure 4). Surface expression of CD9 and GPVI on DIAPH1 R1213X platelets was similar to that of controls after correcting for platelet size by FSC on flow cytometry (Figure 4C). Total platelet lysates were tested for MMP-9 content and activity and both were found to be notably elevated in the DIAPH1 patients compared to controls (Figure 5).
Halloysites modified polyethylene glycol diacrylate/thiolated chitosan double network hydrogel combined with BMP-2 for rat skull regeneration
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2021
Qi-Bin Sun, Chang-Peng Xu, Wen-Qiang Li, Qin-Jun Meng, Hua-Zheng Qu
In the bone regeneration process, angiogenesis could create a capillary network to deliver sufficient nutrients to cells which is crucial for the survival of cells and the healing efficacy of the PEGDA/TCS/T-HNTs/BMP-2 scaffold after implantation [40]. CD31 is known as platelet endothelial cell adhesion molecule-1 which could reflect the formation of blood vessels and served as an endothelial marker of vessels [41]. As shown in immunohistochemical images, many CD31-positive vessels were scattered in the PEGDA/TCS/T-HNTs/BMP-2 group than in the other groups (dotted with blue arrows). The result kept accordance with the previous study. Lvov et al. prepared highly porous chitosan/gelatine/agarose scaffolds (doped with 3–6 wt% halloysite) stimulated neo-vascularization (formation of new blood vessels) in absence of any growth factors or introduced cells [42]. This is due to the composite scaffold doped with HNTs supported cytoskeleton formation, and viability, further guarantee the endothelial cells or smooth muscle cells could penetrate and migrate within the scaffolds to form blood vessel.