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Controlled Therapeutic Delivery in Wound Healing
Published in Emmanuel Opara, Controlled Drug Delivery Systems, 2020
Adam Jorgensen, Zishuai Chou, Sean Murphy
MSCs have shown therapeutic potential for repair and regeneration of tissues damaged by injury or disease. A range of studies have demonstrated MSCs contribute to wound healing through multiple mechanisms, including (i) direct differentiation into keratinocytes [97–99], (ii) inducing angiogenesis through paracrine release VEGF, (iii) recruiting endothelial cells and endothelial progenitor cells (EPCs) to the wound, (iv) promoting regeneration of appendages by releasing cytokines such as EGF and keratinocyte growth factor (KGF), and (v) through anti-inflammatory mechanisms, such as releasing macrophage inflammatory protein-1 (MIP-1) and monocyte chemoattractant protein (MCP) [100,101].
Scaffold Applications for Vascular Tissue Engineering
Published in Gilson Khang, Handbook of Intelligent Scaffolds for Tissue Engineering and Regenerative Medicine, 2017
Young Min Ju, Hyunhee Ahn, John Vossler, Sang Jin Lee, James J. Yoo
ECs form a confluent monolayer on the lumen of blood vessels, forming what is known as the endothelium. The endothelium inhibits the adhesion of circulating proteins and cells.62 ECs regulate vascular tone through the production of various signaling molecules such as prostaglandin and nitric oxide (NO).63 In their healthy, mature state, ECs are quiescent, exhibiting low turnover and low proliferation. Many researchers have thus turned their attention to circulating endothelial progenitor cells (EPCs), which contribute to endothelial repair after injury.64,65 Circulating EPCs can be isolated from peripheral blood, bone marrow, and umbilical cord blood. They have similar physiologic characteristics to mature ECs but are distinguished by their much higher proliferation potential.66
Magnetic Nanoparticles for Organelle Separation
Published in Nguyễn T. K. Thanh, Clinical Applications of Magnetic Nanoparticles, 2018
Mari Takahashi, Shinya Maenosono
In another case, enrichment of stem cells was achieved by magnetic separation for the purpose of regenerative medicine and cell therapy.4 Endothelial progenitor cells (EPCs) are stem cells that differentiate into endothelial cells and thus contribute to the formation of blood vessels and healing of tissues. However, the proportion of EPCs relative to all cells in adult blood is only 0.01%–0.0001%. Therefore, it is necessary to enrich EPCs using techniques such as Ficoll-Paque gradient centrifugation followed by cell culture to obtain sufficient numbers of EPCs for cell therapy, and this process usually requires several days. Wadajkar et al.2 prepared iron oxide particles that had sizes ranging from 50 to 100 μm and were covered with functional multilayers. These iron oxide particles have four components. The outer layer contains EPC-specific anti-CD34 antibodies. The second layer below the outer surface is made of thermoresponsive poly(N-isopropylacrylamide-co-allylamine) to provide a surface for cell attachment and detachment depending on changes in temperature. This polymer has a hydrophobic nature at temperatures above the critical temperature (32°C–34°C) to support cell adhesion but becomes hydrophilic at temperatures below the critical temperature and enhances cell detachment from the particle surface. The polymer layer also contains vascular endothelial growth factors that can be rapidly released for EPC proliferation. The central material consists of a biodegradable core of poly(lactide-co-glycolic acid) (PLGA) microparticles containing basic fibroblast growth factor that are released when PLGA degrades for EPC differentiation. The iron oxide particles are conjugated with PLGA. By adding these magnetic beads to a blood sample and applying an external magnetic field, they succeeded in separating and enriching EPCs from blood samples. This multifunctionality of particles makes magnetic cell separation promising for cell therapy.
3D bioprinting in orthopedics translational research
Published in Journal of Biomaterials Science, Polymer Edition, 2019
XuanQi Zheng, JinFeng Huang, JiaLiang Lin, DeJun Yang, TianZhen Xu, Dong Chen, Xingjie Zan, AiMin Wu
Implanting bioactive tissue scaffolds that are constructed in vitro into bone defects and promoting osteogenesis in vivo through MSCs that are laden in the scaffolds reflect obvious advantages compared to the traditional strategy. However, it is not the whole story. In the treatment of large segmental bone defects, angiogenesis is another important influencing factor. Due to the lack of angiogenesis and the resulting low blood perfusion, the growth and maturation of printed scaffolds become a big problem. Many approaches are devised to promote angiogenesis. One of the most used methods is the implantation of endothelial cells (ECs) in predefined vessel-like channels in a free form manner or by using micromachining technology [54, 55]. Another way to promote angiogenesis is to apply endothelial progenitor cell (EPCs) in bone material scaffolds, which are thought to be involved in vascular construction or in paracrine promoting angiogenesis for the regeneration of blood vessels.
Methylglyoxal induced advanced glycation end products (AGE)/receptor for AGE (RAGE)-mediated angiogenic impairment in bone marrow-derived endothelial progenitor cells
Published in Journal of Toxicology and Environmental Health, Part A, 2018
Jeong-Hyeon Kim, Kyeong-A Kim, Young-Jun Shin, Haram Kim, Arshad Majid, Ok-Nam Bae
Endothelial progenitor cells (EPCs), adult stem cells in endothelial lineage exhibiting angiogenic functions, may be derived from bone marrow (BM) and umbilical cord blood, or found in peripheral blood (Murasawa and Asahara 2005). EPCs play a critical role in neovascularization and regeneration of damaged blood vessels (Kalka et al. 2000; Urbich and Dimmeler 2004; Werner et al. 2003), contributing to maintenance of vascular homeostasis. There has been a growing interest in EPC dysfunctions under pathological conditions such as diabetes (Kim et al. 2014; Sorrentino et al. 2007; Tepper et al. 2002) or toxicant-induced vascular damage (Wu et al. 2013). The prevalence of diabetes has been steadily increasing worldwide (Guariguata et al. 2014), and vascular complications are the leading cause of disability and death in patients with diabetes (Sliwinska-Mosson and Milnerowicz 2017; van Dieren et al. 2010). In particular, angiogenic impairment is considered to play an important role in the pathogenesis of diabetic CVD complications (Kim et al. 2012). The critical role of EPC, a precursor of EC, in both regeneration of injured vessels and angiogenesis is well established (Alev, Ii, and Asahara 2011; Asahara et al. 1999; Tousoulis et al. 2013). Interestingly, several investigators demonstrated that a decrease in the number of EPC and impaired vascular restoration capacity might contribute to the progression of CVD such as delayed wound healing and abnormal peripheral circulation in patients with diabetes (Antonio et al. 2014; Georgescu et al. 2011; Loomans et al. 2004; Tepper et al. 2002).