Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 14Citation - Scopus: 14Development of Biological Meniscus Scaffold: Decellularization Method and Recellularization With Meniscal Cell Population Derived From Mesenchymal Stem Cells(SAGE Publications, 2021) Kara, Aylin; Koçtürk, Semra; Bilici, Gökçen; Havıtçıoğlu, HasanTissue engineering approaches which include a combination of cells and scaffold materials provide an alternative treatment for meniscus regeneration. Decellularization and recellularization techniques are potential treatment options for transplantation. Maintenance of the ultrastructure composition of the extracellular matrix and repopulation with cells are important factors in constructing a biological scaffold and eliminating immunological reactions. The aim of the study is to develop a method to obtain biological functional meniscus scaffolds for meniscus regeneration. For this purpose, meniscus tissue was decellularized by our modified method, a combination of physical, chemical, and enzymatic methods and then recellularized with a meniscal cell population composed of fibroblasts, chondrocytes and fibrochondrocytes that obtained from mesenchymal stem cells. Decellularized and recellularized meniscus scaffolds were analysed biochemically, biomechanically and histologically. Our results revealed that cellular components of the meniscus were successfully removed by preserving collagen and GAG structures without any significant loss in biomechanical properties. Recellularization results showed that the meniscal cells were localized in the empty lacuna on the decellularized meniscus, and also well distributed and proliferated consistently during the cell culture period (p < 0.05). Furthermore, a high amount of DNA, collagen, and GAG contents (p < 0.05) were obtained with the meniscal cell population in recellularized meniscus tissue. The study demonstrates that our decellularization and recellularization methods were effective to develop a biological functional meniscus scaffold and can mimic the meniscus tissue with structural and biochemical features. We predict that the obtained biological meniscus scaffolds may provide avoidance of adverse immune reactions and an appropriate microenvironment for allogeneic or xenogeneic recipients in the transplantation process. Therefore, as a promising candidate, the obtained biological meniscus scaffolds might be verified with a transplantation experiment.Article Citation - WoS: 5Citation - Scopus: 5Low Magnitude High Frequency Vibrations Expedite the Osteogenesis of Bone Marrow Stem Cells on Paper Based 3d Scaffolds(Springer, 2020) Karadaş, Özge; Meşe, Gülistan; Özçivici, EnginAnabolic effects of low magnitude high frequency (LMHF) vibrations on bone tissue were consistently shown in the literature in vivo, however in vitro efforts to elucidate underlying mechanisms are generally limited to 2D cell culture studies. Three dimensional cell culture platforms better mimic the natural microenvironment and biological processes usually differ in 3D compared to 2D culture. In this study, we used laboratory grade filter paper as a scaffold material for studying the effects of LHMF vibrations on osteogenesis of bone marrow mesenchymal stem cells in a 3D system. LMHF vibrations were applied 15 min/day at 0.1 g acceleration and 90 Hz frequency for 21 days to residing cells under quiescent and osteogenic conditions. mRNA expression analysis was performed for alkaline phosphatase (ALP) and osteocalcin (OCN) genes, Alizarin red S staining was performed for mineral nodule formation and infrared spectroscopy was performed for determination of extracellular matrix composition. The highest osteocalcin expression, mineral nodule formation and the phosphate bands arising from the inorganic phase was observed for the cells incubated in osteogenic induction medium with vibration. Our results showed that filter paper can be used as a model scaffold system for studying the effects of mechanical loads on cells, and LMHF vibrations induced the osteogenic differentiation of stem cells.Article Citation - WoS: 28Citation - Scopus: 30Bone Marrow Stem Cells Adapt To Low-Magnitude Vibrations by Altering Their Cytoskeleton During Quiescence and Osteogenesis(TUBITAK, 2015) Demiray, Levent; Özçivici, EnginApplication of mechanical vibrations is anabolic to bone tissue, not only by guiding mature bone cells to increased formation, but also by increasing the osteogenic commitment of progenitor cells. However, the sensitivity and adaptive response of bone marrow stem cells to this loading regimen has not yet been identified. In this study, we subjected mouse bone marrow stem cell line D1-ORL-UVA to daily mechanical vibrations (0.15 g, 90 Hz, 15 min/day) for 7 days, both during quiescence and osteogenic commitment, to identify corresponding ultrastructural adaptations on cellular and molecular levels. During quiescence, mechanical vibrations significantly increased total actin content and actin fiber thickness, as measured by phalloidin staining and fluorescent microscopy. Cellular height also increased, as measured by atomic force microscopy, along with the expression of focal adhesion kinase (PTK2) mRNA levels. During osteogenesis, mechanical vibrations increased the total actin content, actin fiber thickness, and cytoplasmic membrane roughness, with significant increase in Runx2 mRNA levels. These results show that bone marrow stem cells demonstrate similar cytoskeletal adaptations to low-magnitude high-frequency mechanical loads both during quiescence and osteogenesis, potentially becoming more sensitive to additional loads by increased structural stiffness.Article Citation - WoS: 25Citation - Scopus: 27Osteogenic Differentiation of Mesenchymal Stem Cells on Random and Aligned Pan/Ppy Nanofibrous Scaffolds(SAGE Publications, 2019) Selamet, Yusuf; İnce Yardımcı, Atike; Baskan, Öznur; Yılmaz, Selahattin; Meşe, Gülistan; Özçivici, EnginThe aim of this study was to develop random and aligned polyacrilonitrile (PAN)/polypyrrole (PPy) nanofibrous scaffolds by electrospinning technique for osteogenic differentiation of mesenchymal stem cells. Nanofibers were fabricated successfully as straight, smooth, and free from bead formation. The average diameter of random and aligned nanofibers was 268(+/- 49) nm and 225(+/- 72) nm, respectively. Alignment process increased the tensile strength of nanofibers 3.9-fold, while the tensile strain of nanofibers decreased by 78%. PAN/PPy nanofibers were hydrophilic with the contact angle value of about 32 degrees and alignment did not affect the contact angle value. Random and aligned PAN/PPy nanofibers were investigated as a scaffold material for osteogenic differentiation of D1 ORL UVA mouse bone marrow mesenchymal stem cells. Cells were able to attach and grow on nanofibers confirmed by cell viability results. Stem cells that were cultured with osteogenic induction were able to mineralize on electrospun nanofibers based on alizarin red and Von Kossa dye staining. For aligned PPy nanofibers, mineralization occurred in the fiber alignment direction. Consequently, PAN/PPy nanofibrous mats in both random and aligned forms would be potential candidates for bone tissue engineering.Article Citation - WoS: 8Citation - Scopus: 11Application of Low Intensity Mechanical Vibrations for Bone Tissue Maintenance and Regeneration(TÜBİTAK, 2016) Ölçüm, Melis; Baskan, Öznur; Karadaş, Özge; Özçivici, EnginPhysical exercise is beneficial for bone tissue health, yet its usage is limited for preventing osteoporosis. Even though natural for the bone tissue from development to homeostasis, mechanical loads present with a multitude of physical parameters, including amplitude, duration, frequency, and distribution. Utilizing the most beneficial parameters of mechanical loads may potentiate a nonpharmaceutical tool for biotechnology to prevent and treat bone loss related to aging, bedrest, sedentary lifestyles, weightlessness, and other diseases. Low intensity vibrations (LIVs) consist of mechanical loads with amplitudes smaller than loads prescribed by habitual activity, with a higher frequency. In this review, literature covering LIV signal application on bone tissue and cellular and molecular level is presented. Studies indicate that LIV signals are safe, anabolic, and anticatabolic for skeletal tissue and are of great significance in regenerative medicine applications.Article Citation - WoS: 5Citation - Scopus: 5Effects of Intraperitoneal Injection of Allogeneic Bone Marrow-Derived Mesenchymal Stem Cells on Bronchiolitis Obliterans in Mice Model(Tehran University of Medical Sciences, 2017) Işık, Sakine; Uzuner, Nevin; Karaman, Meral; Karaman, Özkan; Kıray, Müge; Kozanoğlu, İlknur; Bağrıyanık, Hüsnü Alper; Arıkan Ayyıldız, Zeynep; Kartal Yandım, Melis; Baran, YusufBone marrow-derived mesenchymal stem cells (BMSCs) can ameliorate a variety of lung diseases such as asthma, lung fibrosis, and acute lung injury by its anti-inflammatory and immunmodulatory effects. In this study, we developed a mouse model of bronchiolitis obliterans (BO) and evaluated the effects of the intraperitoneal administration of BMSCs on lung histopathology and cytokine levels. 25 BALB/c mice were divided into four groups; control group (Group I), BO developed and 1x106 BMSCs-injected group (Group II), non-BO, 1x106 BMSCs-injected group (Group III), and BO developed and saline-injected group (Group IV). Histological and immunohistochemical findings of the lung tissue and the migration of BMSCs to the lung were evaluated using light and confocal microscopy techniques. Confocal microscopy evaluations showed that there was no noteworthy amount of BMSCs in the lung tissue of group III while significant amount of BMSCs was detected in group II. Wall thicknesses of terminal bronchiole and periterminal bronchiolar collagen deposition were significantly lower in group II compared to the group IV (p<0.05). Furthermore, according to the immunohistochemical staining results, CD3, CD4, CD8, CD20, CD68 and neutrophil elastase positive immune cells of group II were stained more positive than group IV cells (p<0.05). IFN-ã IL-2 and TNF-á levels in bronchoalveolar lavage fluid (BALF) were significantly lower in group II compared to group IV (p<0.05). The findings of this study indicate that intraperitoneally administered BMSCs have potent effects on histopatological changes of the lung tissue and cytokine levels in the murine model of BO.Article Citation - Scopus: 7Optimization of Transfection of Green Fluorescent Protein in Pursuing Mesenchymal Stem Cells in Vivo(Aves, 2008) Baran, Yusuf; Ural, Ali Uğur; Avcu, Ferit; Sarper, Meral; Elçi, Pınar; Pekel, AyselObjective: Green Fluorescent Protein (GFP) has been used as a marker of gene expression and a single cell marker in living organisms in cell biology studies. The important areas that GFP is used are expression levels of different genes in different organisms by inserting GFP in these genes and as a marker in living cells. In this study, we tried to optimize transfection of mesenchymal stem cells, (MSCs) used for regeneration of damaged tissues in animals, by GFP containing plasmid vector by which MSCs can be followed in vivo. Material and Methods: To this aim, phM-GFP plasmid vector carrying GFP gene and effectene transfection reagent were used. Result: The data revealed that twice transfection of MSCs resulted in higher expression of GFP for longer times as compared to once transfected MSCs. On the other hand, leaving the chemical transfection agents in the medium induced apoptosis after a while. Conclusion: As a conclusion we suggest the transfection of MSCs twice with 48 hours interval and removal of transfection agents after 8 hours which removed toxic and apoptotic effects of the chemicals.