TY - JOUR A1 - Xu, Jietao A1 - Fahmy-Garcia, Shorouk A1 - Wesdorp, Marinus A. A1 - Kops, Nicole A1 - Forte, Lucia A1 - De Luca, Claudio A1 - Misciagna, Massimiliano Maraglino A1 - Dolcini, Laura A1 - Filardo, Giuseppe A1 - Labberté, Margot A1 - Vancíková, Karin A1 - Kok, Joeri A1 - van Rietbergen, Bert A1 - Nickel, Joachim A1 - Farrell, Eric A1 - Brama, Pieter A. J. A1 - van Osch, Gerjo J. V. M. T1 - Effectiveness of BMP-2 and PDGF-BB adsorption onto a collagen/collagen-magnesium-hydroxyapatite scaffold in weight-bearing and non-weight-bearing osteochondral defect bone repair: in vitro, ex vivo and in vivo evaluation JF - Journal of Functional Biomaterials N2 - Despite promising clinical results in osteochondral defect repair, a recently developed bi-layered collagen/collagen-magnesium-hydroxyapatite scaffold has demonstrated less optimal subchondral bone repair. This study aimed to improve the bone repair potential of this scaffold by adsorbing bone morphogenetic protein 2 (BMP-2) and/or platelet-derived growth factor-BB (PDGF-BB) onto said scaffold. The in vitro release kinetics of BMP-2/PDGF-BB demonstrated that PDGF-BB was burst released from the collagen-only layer, whereas BMP-2 was largely retained in both layers. Cell ingrowth was enhanced by BMP-2/PDFG-BB in a bovine osteochondral defect ex vivo model. In an in vivo semi-orthotopic athymic mouse model, adding BMP-2 or PDGF-BB increased tissue repair after four weeks. After eight weeks, most defects were filled with bone tissue. To further investigate the promising effect of BMP-2, a caprine bilateral stifle osteochondral defect model was used where defects were created in weight-bearing femoral condyle and non-weight-bearing trochlear groove locations. After six months, the adsorption of BMP-2 resulted in significantly less bone repair compared with scaffold-only in the femoral condyle defects and a trend to more bone repair in the trochlear groove. Overall, the adsorption of BMP-2 onto a Col/Col-Mg-HAp scaffold reduced bone formation in weight-bearing osteochondral defects, but not in non-weight-bearing osteochondral defects. KW - tissue engineering KW - regenerative medicine KW - osteochondral lesion KW - biocompatible materials KW - bone morphogenetic proteins KW - platelet-derived growth factor KW - animal model KW - weight-bearing Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-304019 SN - 2079-4983 VL - 14 IS - 2 ER - TY - JOUR A1 - Lotz, C. A1 - Kiesewetter, L. A1 - Schmid, F. F. A1 - Hansmann, J. A1 - Walles, H. A1 - Groeber-Becker, F. T1 - Replacing the Draize eye test: impedance spectroscopy as a 3R method to discriminate between all GHS categories for eye irritation JF - Scientific Reports N2 - Highly invasive animal based test procedures for risk assessment such as the Draize eye test are under increasing criticism due to poor transferability for the human organism and animal-welfare concerns. However, besides all efforts, the Draize eye test is still not completely replaced by alternative animal-free methods. To develop an in vitro test to identify all categories of eye irritation, we combined organotypic cornea models based on primary human cells with an electrical readout system that measures the impedance of the test models. First, we showed that employing a primary human cornea epithelial cell based model is advantageous in native marker expression to the primary human epidermal keratinocytes derived models. Secondly, by employing a non-destructive measuring system based on impedance spectroscopy, we could increase the sensitivity of the test system. Thereby, all globally harmonized systems categories of eye irritation could be identified by repeated measurements over a period of 7 days. Based on a novel prediction model we achieved an accuracy of 78% with a reproducibility of 88.9% to determine all three categories of eye irritation in one single test. This could pave the way according to the 3R principle to replace the Draize eye test. KW - biological models KW - electrical and electronic engineering KW - regenerative medicine KW - tissue engineering KW - toxicology Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-177492 VL - 8 IS - 15049 ER - TY - JOUR A1 - Jakob, Franz A1 - Ebert, Regina A1 - Rudert, Maximilian A1 - Nöth, Ulrich A1 - Walles, Heike A1 - Docheva, Denitsa A1 - Schieker, Matthias A1 - Meinel, Lorenz A1 - Groll, Jürgen T1 - In situ guided tissue regeneration in musculoskeletal diseases and aging JF - Cell and Tissue Research N2 - In situ guided tissue regeneration, also addressed as in situ tissue engineering or endogenous regeneration, has a great potential for population-wide “minimal invasive” applications. During the last two decades, tissue engineering has been developed with remarkable in vitro and preclinical success but still the number of applications in clinical routine is extremely small. Moreover, the vision of population-wide applications of ex vivo tissue engineered constructs based on cells, growth and differentiation factors and scaffolds, must probably be deemed unrealistic for economic and regulation-related issues. Hence, the progress made in this respect will be mostly applicable to a fraction of post-traumatic or post-surgery situations such as big tissue defects due to tumor manifestation. Minimally invasive procedures would probably qualify for a broader application and ideally would only require off the shelf standardized products without cells. Such products should mimic the microenvironment of regenerating tissues and make use of the endogenous tissue regeneration capacities. Functionally, the chemotaxis of regenerative cells, their amplification as a transient amplifying pool and their concerted differentiation and remodeling should be addressed. This is especially important because the main target populations for such applications are the elderly and diseased. The quality of regenerative cells is impaired in such organisms and high levels of inhibitors also interfere with regeneration and healing. In metabolic bone diseases like osteoporosis, it is already known that antagonists for inhibitors such as activin and sclerostin enhance bone formation. Implementing such strategies into applications for in situ guided tissue regeneration should greatly enhance the efficacy of tailored procedures in the future. KW - in situ guided tissue regeneration KW - stem cells KW - scaffolds KW - regenerative medicine KW - mesenchymal tissues Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-124738 VL - 347 IS - 3 ER - TY - JOUR A1 - Hinderer, Svenja A1 - Shen, Nian A1 - Ringuette, Léa-Jeanne A1 - Hansmann, Jan A1 - Reinhardt, Dieter P A1 - Brucker, Sara Y A1 - Davis, Elaine C A1 - Schenke-Layland, Katja T1 - In vitro elastogenesis: instructing human vascular smooth muscle cells to generate an elastic fiber-containing extracellular matrix scaffold JF - Biomedical Materials N2 - Elastic fibers are essential for the proper function of organs including cardiovascular tissues such as heart valves and blood vessels. Although (tropo)elastin production in a tissue-engineered construct has previously been described, the assembly to functional elastic fibers in vitro using human cells has been highly challenging. In the present study, we seeded primary isolated human vascular smooth muscle cells (VSMCs) onto 3D electrospun scaffolds and exposed them to defined laminar shear stress using a customized bioreactor system. Increased elastin expression followed by elastin deposition onto the electrospun scaffolds, as well as on newly formed fibers, was observed after six days. Most interestingly, we identified the successful deposition of elastogenesis-associated proteins, including fibrillin-1 and -2, fibulin-4 and -5, fibronectin, elastin microfibril interface located protein 1 (EMILIN-1) and lysyl oxidase (LOX) within our engineered constructs. Ultrastructural analyses revealed a developing extracellular matrix (ECM) similar to native human fetal tissue, which is composed of collagens, microfibrils and elastin. To conclude, the combination of a novel dynamic flow bioreactor and an electrospun hybrid polymer scaffold allowed the production and assembly of an elastic fiber-containing ECM. KW - elastin KW - elastic fibers KW - electrospinning KW - tissue engineering KW - regenerative medicine KW - heart valve KW - cardiovascular Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-254074 VL - 10 IS - 3 ER - TY - JOUR A1 - Bachmann, Julia A1 - Ehlert, Elias A1 - Becker, Matthias A1 - Otto, Christoph A1 - Radeloff, Katrin A1 - Blunk, Torsten A1 - Bauer-Kreisel, Petra T1 - Ischemia-like stress conditions stimulate trophic activities of adipose-derived stromal/stem cells JF - Cells N2 - Adipose-derived stromal/stem cells (ASCs) have been shown to exert regenerative functions, which are mainly attributed to the secretion of trophic factors. Upon transplantation, ASCs are facing an ischemic environment characterized by oxygen and nutrient deprivation. However, current knowledge on the secretion capacity of ASCs under such conditions is limited. Thus, the present study focused on the secretory function of ASCs under glucose and oxygen deprivation as major components of ischemia. After exposure to glucose/oxygen deprivation, ASCs maintained distinct viability, but the metabolic activity was greatly reduced by glucose limitation. ASCs were able to secrete a broad panel of factors under glucose/oxygen deprivation as revealed by a cytokine antibody array. Quantification of selected factors by ELISA demonstrated that glucose deprivation in combination with hypoxia led to markedly higher secretion levels of the angiogenic and anti-apoptotic factors IL-6, VEGF, and stanniocalcin-1 as compared to the hypoxic condition alone. A conditioned medium of glucose/oxygen-deprived ASCs promoted the viability and tube formation of endothelial cells, and the proliferation and migration of fibroblasts. These findings indicate that ASCs are stimulated by ischemia-like stress conditions to secrete trophic factors and would be able to exert their beneficial function in an ischemic environment. KW - adipose-derived stromal/stem cells (ASCs) KW - regenerative medicine KW - secretion KW - trophic factors KW - ischemia KW - glucose starvation KW - hypoxia Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-211233 SN - 2073-4409 VL - 9 IS - 9 ER -