Browsing by Subject "Cartilage regeneration"

Now showing 1 - 5 of 5

Open Access
Development and characterization of peptide nanofibers for cartilage regeneration
(2015-09) Yaylacı, Seher
Articular cartilage is a tissue that is continuously exposed to cyclical compressive stresses, but exhibits no capacity for self-healing following trauma. Cartilage has a dense extracellular matrix that is sparsely populated with cells, and the whole tissue lacks blood and lymphatic vessels, which complicates the cell infiltration response that ordinarily occurs during inflammation. In addition, the only cell type capable of synthesizing new cartilage matrix lies deeper in the tissue, near the bone boundary, and due to the dense extracellular matrix, chondrocytes cannot migrate to the defect site following injury. Consequently, cartilage tissue cannot effectively respond to treatment options. Treatment options exist for the short-term reduction of pain in smaller defects, but larger injuries necessitate tissue donation, and there is a severe shortage of articular cartilage that can be donated for autografting. Microfracture and autologous chondrocyte implantation are the current treatment options that use cellular therapy for the repair of cartilage. However, the cartilage tissue that forms in the course of these treatments is not the functional hyaline cartilage, but rather fibrous cartilage, which is mechanically weaker and degenerates over time. Tissue engineering studies using biodegradable scaffolds and autologous cells are gaining importance as effective long-term treatment options for the postinjury production of hyaline cartilage. Such scaffold systems are designed to be biodegradable and bioactive, which allows them to induce new tissue formation in shorter periods of time. In this dissertation, peptide nanofibers mimicking glycosaminoglycan molecules, which are important constituents of cartilage extracellular matrix, are designed and the effectiveness of these materials in terms of chondrocyte differentation are tested under in vitro conditions. As a follow-up study to in vitro experiments, the capacity of bioactive peptide nanofibers to support cartilage regeneration is evaluated in the rabbit osteochondral defect model. Structural and mechanical properties of newly deposited cartilage are highly dependent on the quality and quantity of its extracellular matrix, which also has a major impact on the integration of replacement cartilage into the surrounding healthy tissue. Signals provided by bioactive peptide nanofibers to cells at the defect site can strongly alter the quality of the newly synthesized extracellular matrix. Consequently, we designed glycosaminoglycanmimetic peptide nanofibers that closely imitate the structure of the native cartilage extracellular matrix and demonstrated that these nanofiber networks are able to induce the synthesis of collagen II and aggrecan molecules, which are the main constituents of cartilage tissue, during chondrogenic differentiation.
Open Access
Materials for articular cartilage regeneration
(Bentham Science Publishers B.V., 2012) Tombuloglu, Ayşegül; Tekinay, Ayşe B.; Güler, Mustafa O.
Many health problems remaining to be untreatable throughout the human history can be overcome by utilizing new biomedical materials. Healing cartilage defects is one of the problems causing significant health issue due to low regeneration capacity of the cartilage tissue. Scaffolds as three-dimensional functional networks provide promising tools for complete regeneration of the cartilage tissue. Diversity of materials and fabrication methods give rise to many forms of scaffolds including injectable and mechanically stable ones. Various approaches can be considered depending on the condition of cartilage defect. A scaffold should maintain tissue function within a short time, and should be easily applied in order to minimally harm the body. This review will cover several patents and other publications on materials for cartilage regeneration with an outlook on essential characteristics of materials and scaffolds.
Open Access
Peptide-based materials for cartilage tissue regeneration
(Springer New York LLC, 2017) Hastar, Nurcan; Arslan, Elif.; Güler, Mustafa O.; Tekinay, Ayse B.
Cartilaginous tissue requires structural and metabolic support after traumatic or chronic injuries because of its limited capacity for regeneration. However, current techniques for cartilage regeneration are either invasive or ineffective for long-term repair. Developing alternative approaches to regenerate cartilage tissue is needed. Therefore, versatile scaffolds formed by biomaterials are promising tools for cartilage regeneration. Bioactive scaffolds further enhance the utility in a broad range of applications including the treatment of major cartilage defects. This chapter provides an overview of cartilage tissue, tissue defects, and the methods used for regeneration, with emphasis on peptide scaffold materials that can be used to supplement or replace current medical treatment options. © Springer International Publishing AG 2017.
Open Access
Supramolecular GAG-like self-assembled glycopeptide nanofibers Induce chondrogenesis and cartilage regeneration
(American Chemical Society, 2016) Yaylaci, U. S.; Ekiz, M. S.; Arslan, E.; Can, N.; Kilic, E.; Ozkan, H.; Orujalipoor, I.; Ide, S.; Tekinay, A. B.; Güler, Mustafa O.
Glycosaminoglycans (GAGs) and glycoproteins are vital components of the extracellular matrix, directing cell proliferation, differentiation, and migration and tissue homeostasis. Here, we demonstrate supramolecular GAG-like glycopeptide nanofibers mimicking bioactive functions of natural hyaluronic acid molecules. Self-assembly of the glycopeptide amphiphile molecules enable organization of glucose residues in close proximity on a nanoscale structure forming a supramolecular GAG-like system. Our in vitro culture results indicated that the glycopeptide nanofibers are recognized through CD44 receptors, and promote chondrogenic differentiation of mesenchymal stem cells. We analyzed the bioactivity of GAG-like glycopeptide nanofibers in chondrogenic differentiation and injury models because hyaluronic acid is a major component of articular cartilage. Capacity of glycopeptide nanofibers on in vivo cartilage regeneration was demonstrated in microfracture treated osteochondral defect healing. The glycopeptide nanofibers act as a cell-instructive synthetic counterpart of hyaluronic acid, and they can be used in stem cell-based cartilage regeneration therapies.
Open Access
Therapeutic nanomaterials for cartilage regeneration
(John Wiley & Sons, 2016-03-11) Arslan, Elif; Üstün Yaylacı, Seher; Güler, Mustafa O.; Tekinay, Ayşe B.; Güler, Mustafa O.; Tekinay, Ayşe B.
Articular cartilage (AC) is the main focus of this chapter and indeed most cartilage regeneration studies, since it is commonly affected by diseases and traumatic injuries that necessitate its therapeutic regeneration. There are four main approaches for cartilage regeneration: cultured cell implantation, engineered tissue construct implantation, scaffoldless tissue regeneration, and guided tissue regeneration. Cartilage growth, development, and repair are dependent on both biomechanical and biological signals. The most important growth factors used in cartilage regeneration and tissue engineering approaches are the transforming growth factor ß (TGF‐ß) family members, particularly TGF‐ß1 and TGF‐ß3. Overall, new strategies in the field of cartilage regeneration focus on the unique biochemical and physical properties of native cartilage to design novel tissue constructs that are decorated with cartilage‐specific signals and display suitable anatomical geometries and mechanical properties for the treatment of large tissue defects.