scholarly journals Hydroxyapatite-Coated Titanium by Micro-Arc Oxidation and Steam–Hydrothermal Treatment Promotes Osseointegration

2021 ◽  
Vol 9 ◽  
Author(s):  
Xiaojun Wang ◽  
Lina Mei ◽  
Xuesheng Jiang ◽  
Mingchao Jin ◽  
Yan Xu ◽  
...  
Keyword(s):  
Hydrothermal Treatment ◽  
Cell Attachment ◽  
Vascular Endothelial ◽  
Matrix Mineralization ◽  
X Ray ◽  
Micro Arc Oxidation ◽  
Surface Physicochemical Properties ◽  
Endothelial Growth Factor

Titanium (Ti)-based alloys are widely used in tissue regeneration with advantages of improved biocompatibility, high mechanical strength, corrosion resistance, and cell attachment. To obtain bioactive bone–implant interfaces with enhanced osteogenic capacity, various methods have been developed to modify the surface physicochemical properties of bio-inert Ti and Ti alloys. Nano-structured hydroxyapatite (HA) formed by micro-arc oxidation (MAO) is a synthetic material, which could facilitate osteoconductivity, osteoinductivity, and angiogenesis on the Ti surface. In this paper, we applied MAO and steam–hydrothermal treatment (SHT) to produce HA-coated Ti, hereafter called Ti–M–H. The surface morphology of Ti–M–H1 was observed by scanning electron microscopy (SEM), and the element composition and the roughness of Ti–M–H1 were analyzed by energy-dispersive X-ray analysis, an X-ray diffractometer (XRD), and Bruker stylus profiler, demonstrating the deposition of nano-HA particles on Ti surfaces that were composed of Ca, P, Ti, and O. Then, the role of Ti–M–H in osteogenesis and angiogenesis in vitro was evaluated. The data illustrated that Ti–M–H1 showed a good compatibility with osteoblasts (OBs), which promoted adhesion, spreading, and proliferation. Additionally, the secretion of ALP, Col-1, and extracellular matrix mineralization was increased by OBs treated with Ti–M–H1. Ti–M–H1 could stimulate endothelial cells to secrete vascular endothelial growth factor and promote the formation of capillary-like networks. Next, it was revealed that Ti–M–H1 also suppressed inflammation by activating macrophages, while releasing multiple active factors to mediate osteogenesis and angiogenesis. Finally, in vivo results uncovered that Ti–M–H1 facilitated a higher bone-to-implant interface and was more attractive for the dendrites, which promoted osseointegration. In summary, MAO and SHT-treated Ti–M–H1 not only promotes in vitro osteogenesis and angiogenesis but also induces M2 macrophages to regulate the immune environment, which enhances the crosstalk between osteogenesis and angiogenesis and ultimately accelerates the process of osseointegration in vivo.

scholarly journals Organic Nanocarriers for Bevacizumab Delivery: An Overview of Development, Characterization and Applications

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4127
Author(s):  
Aline de Cristo Soares Alves ◽  
Franciele Aline Bruinsmann ◽  
Silvia Stanisçuaski Guterres ◽  
Adriana Raffin Pohlmann
Keyword(s):  
Monoclonal Antibody ◽  
Physicochemical Characterization ◽  
Vascular Endothelial ◽  
Organic Nanoparticles ◽  
Humanized Monoclonal Antibody ◽  
Angiogenesis Process ◽  
Endothelial Growth Factor ◽  
Drug Pharmacokinetics

Bevacizumab (BCZ) is a recombinant humanized monoclonal antibody against the vascular endothelial growth factor, which is involved in the angiogenesis process. Pathologic angiogenesis is observed in several diseases including ophthalmic disorders and cancer. The multiple administrations of BCZ can cause adverse effects. In this way, the development of controlled release systems for BCZ delivery can promote the modification of drug pharmacokinetics and, consequently, decrease the dose, toxicity, and cost due to improved efficacy. This review highlights BCZ formulated in organic nanoparticles providing an overview of the physicochemical characterization and in vitro and in vivo biological evaluations. Moreover, the main advantages and limitations of the different approaches are discussed. Despite difficulties in working with antibodies, those nanocarriers provided advantages in BCZ protection against degradation guaranteeing bioactivity maintenance.

Regulation of Vascular Endothelial Growth Factor by Tamoxifen in vitro and in vivo

2003 ◽  
Vol 55 (2) ◽  
pp. 119-124 ◽  
Author(s):  
Michael D. Mueller ◽  
Elizabeth A. Pritts ◽  
Charles J. Zaloudek ◽  
Ekkehard Dreher ◽  
Robert N. Taylor
Keyword(s):  
Vascular Endothelial Growth Factor ◽  
Growth Factor ◽  
Vascular Endothelial ◽  
Endothelial Growth Factor

In vitro evaluation of freeze-drying chitosan-mineralized collagen/Mg–Ca alloy composites for osteogenesis

2022 ◽  
pp. 088532822110492
Author(s):  
Zhenbao Zhang ◽  
Xirao Sun ◽  
Jingxin Yang ◽  
Chengyue Wang
Keyword(s):  
Corrosion Resistance ◽  
Bone Repair ◽  
Umbilical Vein ◽  
Matrix Mineralization ◽  
Repair Materials ◽  
Micro Arc Oxidation ◽  
Umbilical Vein Endothelial Cells ◽  
Endothelial Growth Factor ◽  
Mineralized Collagen

Magnesium (Mg) alloy with good mechanical properties and biodegradability is considered as one of the ideal bone repair materials. However, the rapid corrosion of Mg-based metals can pose harm to the function of an implant in clinical applications. In this study, micro-arc oxidation coating was prepared on the surface of the Mg–Ca matrix, then the chitosan and mineralized collagen (nano-hydroxyapatite/collagen; nHAC) were immobilized on the surface of the MAO/Mg–Ca matrix to construct the CS-nHAC/Mg–Ca composites of different component proportions (the ratio of CS to nHAC is 2:1, 1:1, and 1:2, respectively). The corrosion resistance, osteogenic activity, and angiogenic ability were extensively investigated. The results indicated that the CS-nHAC reinforcement materials can improve the corrosion resistance of the Mg matrix significantly and promote the proliferation and adhesion of mouse embryo osteoblast precursor cells (MC3T3-E1) and human umbilical vein endothelial cells (HUVECs). In addition, the CS-nHAC/Mg–Ca composites can not only promote the alkaline phosphatase (ALP) activity and extracellular matrix mineralization of MC3T3-E1 cells but also enhance the migration motility and vascular endothelial growth factor (VEGF) expression of HUVECs. Meanwhile, the 2CS-1nHAC/Mg–Ca composite exhibited the optimum function characteristics compared with other samples. Therefore, considering the improvement of corrosion resistance and biocompatibility, the CS-nHAC/Mg–Ca composites are expected to be a promising orthopedic implant.

Interaction between vascular endothelial cells and vascular intimal spindle-shaped cells in vitro

1983 ◽  
Vol 60 (1) ◽  
pp. 89-102
Author(s):  
D de Bono ◽  
C. Green
Keyword(s):  
Extracellular Matrix ◽  
Endothelial Cells ◽  
Vascular Endothelial Cells ◽  
Three Dimensional ◽  
Vascular Endothelial ◽  
Pure Cultures ◽  
Species Specific ◽  
Endothelial Growth Factor

The interactions between human or bovine vascular endothelial cells and fibroblast-like vascular intimal spindle-shaped cells have been studied in vitro, using species-specific antibodies to identify the different components in mixed cultures. Pure cultures of endothelial cells grow as uniform, nonoverlapping monolayers, but this growth pattern is lost after the addition of spindle cells, probably because the extracellular matrix secreted by the latter causes the endothelial cells to modify the way they are attached to the substrate. The result is a network of tubular aggregates of endothelial cells in a three-dimensional ‘polylayer’ of spindle-shaped cells. On the other hand, endothelial cells added to growth-inhibited cultures of spindle-shaped cells will grow in sheets over the surface of the culture. Human endothelial cells grown in contact with spindle-shaped cells have a reduced requirement for a brain-derived endothelial growth factor. The interactions of endothelial cells and other connective tissue cells in vitro may be relevant to the mechanisms of endothelial growth and blood vessel formation in vivo, and emphasize the potential importance of extracellular matrix in controlling endothelial cell behaviour.

Vascular Endothelial Growth Factor Inhibits the Development of Dendritic Cells and Dramatically Affects the Differentiation of Multiple Hematopoietic Lineages In Vivo

Blood ◽  
1998 ◽  
Vol 92 (11) ◽  
pp. 4150-4166 ◽  
Author(s):  
Dmitry Gabrilovich ◽  
Tadao Ishida ◽  
Tsunehiro Oyama ◽  
Sophia Ran ◽  
Vladimir Kravtsov ◽  
...  
Keyword(s):  
Stem Cells ◽  
Vascular Endothelial Growth Factor ◽  
Dendritic Cells ◽  
Growth Factor ◽  
System Control ◽  
Vascular Endothelial ◽  
Almost All ◽  
Endothelial Growth Factor

Abstract Defective function of dendritic cells (DC) in cancer has been recently described and may represent one of the mechanisms of tumor evasion from immune system control. We have previously shown in vitro that vascular endothelial growth factor (VEGF), produced by almost all tumors, is one of the tumor-derived factors responsible for the defective function of these cells. In this study, we investigated whether in vivo infusion of recombinant VEGF could reproduce the observed DC dysfunction. Continuous VEGF infusion, at rates as low as 50 ng/h (resulting in serum VEGF concentrations of 120 to 160 pg/mL), resulted in a dramatic inhibition of dendritic cell development, associated with an increase in the production of B cells and immature Gr-1+ myeloid cells. Infusion of VEGF was associated with inhibition of the activity of the transcription factor NF-κB in bone marrow progenitor cells. Experiments in vitro showed that VEGF itself, and not factors released by VEGF-activated endothelial cells, affected polypotent stem cells resulting in the observed abnormal hematopoiesis. These data suggest that VEGF, at pathologically relevant concentrations in vivo, may exert effects on pluripotent stem cells that result in blocked DC development as well as affect many other hematopoietic lineages.

scholarly journals Experimental Models in Neovascular Age Related Macular Degeneration

2020 ◽  
Vol 21 (13) ◽  
pp. 4627
Author(s):  
Olivia Rastoin ◽  
Gilles Pagès ◽  
Maeva Dufies
Keyword(s):  
Macular Degeneration ◽  
Experimental Models ◽  
Age Related Macular Degeneration ◽  
Vascular Endothelial ◽  
In Vivo Models ◽  
Age Related ◽  
Decoy Receptors ◽  
Endothelial Growth Factor

Neovascular age-related macular degeneration (vAMD), characterized by the neo-vascularization of the retro-foveolar choroid, leads to blindness within few years. This disease depends on angiogenesis mediated by the vascular endothelial growth factor A (VEGF) and to inflammation. The only available treatments consist of monthly intravitreal injections of antibodies directed against VEGF or VEGF/VEGFB/PlGF decoy receptors. Despite their relative efficacy, these drugs only delay progression to blindness and 30% of the patients are insensitive to these treatments. Hence, new therapeutic strategies are urgently needed. Experimental models of vAMD are essential to screen different innovative therapeutics. The currently used in vitro and in vivo models in ophthalmic translational research and their relevance are discussed in this review.

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