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Dentin-Pulp Complex Regeneration
Published in Vincenzo Guarino, Marco Antonio Alvarez-Pérez, Current Advances in Oral and Craniofacial Tissue Engineering, 2020
Amaury Pozos-Guillén, Héctor Flores
Growth factors are proteins that regulate many aspects of cellular function, including survival, morphogenesis, proliferation, migration, apoptosis, differentiation and secretory processes of cells. Growth factors and cytokines are polypeptides or proteins that bind to specific receptors on the surface of target cells; they may act as signaling molecules that modulate cell behavior by mediating intracellular communication. It has been reported that growth factors, as well as bone morphogenic proteins, are essential for tissue engineering in endodontics. Growth factors may be released from the dentin matrix as a result of both injury events to the tissues and clinical restorative procedures. Also, growth factors may be molecules in the signaling of reactionary and reparative dentinogenesis processes (Lind 1996; Smith 2003).
The Extracellular Matrix as a Substrate for Stem Cell Growth and Development and Tissue Repair
Published in Richard K. Burt, Alberto M. Marmont, Stem Cell Therapy for Autoimmune Disease, 2019
Stephen F. Badylak, Mervin C. Yoder
The characteristic of the intact ECM that distinguishes it from other substrates for cell attachment, growth and differentiation, such as purified collagens, fibronectin or laminin, is its diversity of structural and functional proteins. In addition, the associated bioactive molecules that reside within the ECM and their unique spatial distribution provides a reservoir of biologic signals. Although cytokines and growth factors are present within ECM in very small quantities, they act as potent modulators of cell behavior. The list of growth factors is extensive and includes vascular endothelial cell growth factor (VEGF), the fibroblast growth factor (FGF) family, epithelial cell growth factor (EGF), transforming growth factor beta (TGF-beta), keratinocyte growth factor (KGF), hepatocyte growth factor (HGF) and platelet derived growth factor (PDGF), among others. These factors tend to exist in multiple isoforms, each with its specific biologic activity. Purified forms of growth factors and biologic peptides have been investigated in recent years as therapeutic means of encouraging blood vessel formation (e.g., VEGF), inhibiting blood vessel formation (angiostatin), stimulating deposition of granulation tissue (PDGF), and encouraging epithelialization of wounds (KGF). However, this therapeutic approach has struggled with determination of optimal dose, the ability to sustain and localize the release at the desired site, and the inability to turn the factor “on” and “off” as needed during the course of tissue repair.
An Assessment of the Role of Polymers for Drug Delivery in Tissue Engineering
Published in Ijeoma F. Uchegbu, Andreas G. Schätzlein, Polymers in Drug Delivery, 2006
Patrick J. Ginty, Steven M. Howdle, Felicity R.A.J. Rose, Kevin M. Shakesheff
In order to achieve realistic tissue reconstruction, it is important that cells receive both physical support and chemical direction during growth. For example, the cells that form cartilage, chondrocytes, produce collagen so that it can provide mechanical support and assist tissue growth. Collagen is a naturally occurring structural protein that binds to and surrounds the cells to form the extracellular matrix of cartilage (ECM). The role of the ECM is to provide the necessary physical and biological support to the cells during tissue formation [1]. A polymer scaffold or matrix can take on this role of physical and biological support, as will be discussed later. However, some degree of chemical direction is needed to supplement the support given by the ECM. Chemical direction is given by endogenous proteins known as growth factors and cytokines. Growth factors are molecules that stimulate the cellular processes that drive tissue growth, such as proliferation and differentiation. The term cytokine is generally used to describe chemical messengers secreted by cells of the immune system that mediate the immune response [7]. In order to deliver these molecules to the cells in question, some kind of controlled-release device is required that will allow sustained and effective delivery.
Synthetic electrospun nanofibers as a supportive matrix in osteogenic differentiation of induced pluripotent stem cells
Published in Journal of Biomaterials Science, Polymer Edition, 2022
Arash Azari Matin, Khashayar Fattah, Sahand Saeidpour Masouleh, Reza Tavakoli, Seyed Armin Houshmandkia, Afshin Moliani, Reza Moghimimonfared, Sahar Pakzad, Elaheh Dalir Abdolahinia
Growth factors have a great role in modulating cell fate and function. They are involved in cell survival, function, proliferation, and differentiation. It is shown that basic fibroblast growth factor (bFGF) enhances the osteogenic differentiation of iPSCs cultured on the synthetic PCL‐PVDF electrospun scaffold [77]. The roles of bFGF in the proliferation and differentiation of progenitors have been shown in a study by Hanada et al. [120]. This factor is also involved in angiogenesis. Therefore, the use of bFGF not only enhances the proliferation and differentiation of cultured stem cells but also could increase the angiogenesis and survival of the implanted scaffold [121,122]. Xu et al. also evaluated the function of connective tissue growth factor (CTGF) in promoting the osteogenesis of the electrospun scaffold. In this study, a 15-aminoacid peptide of the CT domain of CTGF, called peptide H1, was introduced into the SF/PLCL composite fibers. The incorporation of peptide H1 increased the osteogenic differentiation of iPSCs [60]. The peptide has a hydrophilic nature due to the presence of lysine (Lys) and arginine (Arg) residues and promotes cell attachment and proliferation [60]. The same results were obtained when vitronectin peptide was incorporated into the PCL fibers. Vitronectin has also a hydrophilic nature and therefore facilitates cell attachment and proliferation [53].
Osteoconductive and osteoinductive biodegradable microspheres serving as injectable micro-scaffolds for bone regeneration
Published in Journal of Biomaterials Science, Polymer Edition, 2021
Jianping Mao, Pengfei Wei, Zuoying Yuan, Wei Jing, Jingjing Cao, Guangping Li, Jianxun Guo, Honggang Wang, Dafu Chen, Qing Cai
Growth factors play important roles in regulating cell activities during native tissue development. Bone morphogenetic proteins (BMPs) are initially isolated from bone tissues, which have been widely applied in BTE researches to promote cell osteogenic differentiation in vitro and bone regeneration in vivo [22,23]. Polymeric microspheres prepared via (water-in-oil)-in-water (W1/O/W2) double emulsion are well-known carriers for protein-type drugs by dissolving the drugs in the inner water phase (W1), achieving controlled release behaviors of the embedded drugs in dependence on preparation parameters. For BTE, BMPs-loaded biodegradable microspheres have been implanted into defects sites to accelerate bone regeneration [24]. However, growth factors are liable to lose their bioactivity during the microsphere preparation because they are sensitive to the ultrasonication, which is a key step involved in the formation of the water-in-oil emulsion [25,26]. In view of the facts that BMPs demonstrate natural affinity to HA [27,28], therefore, BMPs can be adsorbed onto HA-coated BTE scaffolds and delivered to bone defects without jeopardizing their bioactivity [29].
Dramatic promotion of wound healing using a recombinant human-like collagen and bFGF cross-linked hydrogel by transglutaminase
Published in Journal of Biomaterials Science, Polymer Edition, 2019
Yayuan Guo, Bing Xu, Yihang Wang, Yan Li, He Si, Xiaoyan Zheng, Zhuoyue Chen, Fulin Chen, Daidi Fan
It has been found that many growth factors, play a significant role in the dynamic stages [2, 3], such as vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), platelet-derived growth factor (PDGF) and epidermal growth factors (EGF). The bFGF, which is the primary promoter for cell proliferation [4, 5], has been shown to play a part in some fields of the medicine, including neovascularization [6], wound repair [7] and tissue regeneration [8], as well as reconstruction of cartilage and bone [9]. In addition, the released bFGF has obvious chemotactic activity on wound cells, and is able to induce some types of cells, including inflammatory cells, fibroblasts, vascular endothelial cells to get together at the wound site [10], activating the phagocytic function of macrophages and clearing local necrotic tissue and bacteria to improve the body’s immune activity, which significantly reduce the chance of wound tissue infection [11]. However, the bFGF could lose its bioactivity rapidly in normal physiological conditions without stabilization [12]. Therefore, it is essential to integrate the bFGF into sustainable drug-releasing systems, such as hydrogels, which can enhance the efficiency of bFGF utilization.