TY - JOUR A1 - Tomasch, Janine A1 - Maleiner, Babette A1 - Heher, Philipp A1 - Rufin, Manuel A1 - Andriotis, Orestis G. A1 - Thurner, Philipp J. A1 - Redl, Heinz A1 - Fuchs, Christiane A1 - Teuschl-Woller, Andreas H. T1 - Changes in Elastic Moduli of Fibrin Hydrogels Within the Myogenic Range Alter Behavior of Murine C2C12 and Human C25 Myoblasts Differently JF - Froniers in Bioengineering and Biotechnology N2 - Fibrin hydrogels have proven highly suitable scaffold materials for skeletal muscle tissue engineering in the past. Certain parameters of those types of scaffolds, however, greatly affect cellular mechanobiology and therefore the myogenic outcome. The aim of this study was to identify the influence of apparent elastic properties of fibrin scaffolds in 2D and 3D on myoblasts and evaluate if those effects differ between murine and human cells. Therefore, myoblasts were cultured on fibrin-coated multiwell plates (“2D”) or embedded in fibrin hydrogels (“3D”) with different elastic moduli. Firstly, we established an almost linear correlation between hydrogels’ fibrinogen concentrations and apparent elastic moduli in the range of 7.5 mg/ml to 30 mg/ml fibrinogen (corresponds to a range of 7.7–30.9 kPa). The effects of fibrin hydrogel elastic modulus on myoblast proliferation changed depending on culture type (2D vs 3D) with an inhibitory effect at higher fibrinogen concentrations in 3D gels and vice versa in 2D. The opposite effect was evident in differentiating myoblasts as shown by gene expression analysis of myogenesis marker genes and altered myotube morphology. Furthermore, culture in a 3D environment slowed down proliferation compared to 2D, with a significantly more pronounced effect on human myoblasts. Differentiation potential was also substantially impaired upon incorporation into 3D gels in human, but not in murine, myoblasts. With this study, we gained further insight in the influence of apparent elastic modulus and culture type on cellular behavior and myogenic outcome of skeletal muscle tissue engineering approaches. Furthermore, the results highlight the need to adapt parameters of 3D culture setups established for murine cells when applied to human cells. KW - Tissue Engineering KW - Fibrin KW - Hydrogel KW - Biomaterials KW - Cell Culture Y1 - VL - 10 SP - 836520 ER - TY - JOUR A1 - Deininger, Christian A1 - Wagner, Andrea A1 - Heimel, Patrick A1 - Salzer, Elias A1 - Monforte Vila, Xavier A1 - Weißenbacher, Nadja A1 - Grillari, Johannes A1 - Redl, Heinz A1 - Wichlas, Florian A1 - Freude, Thomas A1 - Tempfer, Herbert A1 - Teuschl-Woller, Andreas A1 - Traweger, Andreas T1 - Enhanced BMP-2-Mediated Bone Repair Using an Anisotropic Silk Fibroin Scaffold Coated with Bone-like Apatite JF - Int. J. Mol. Sci. N2 - The repair of large bone defects remains challenging and often requires graft material due to limited availability of autologous bone. In clinical settings, collagen sponges loaded with excessive amounts of bone morphogenetic protein 2 (rhBMP-2) are occasionally used for the treatment of bone non-unions, increasing the risk of adverse events. Therefore, strategies to reduce rhBMP-2 dosage are desirable. Silk scaffolds show great promise due to their favorable biocompatibility and their utility for various biofabrication methods. For this study, we generated silk scaffolds with axially aligned pores, which were subsequently treated with 10× simulated body fluid (SBF) to generate an apatitic calcium phosphate coating. Using a rat femoral critical sized defect model (CSD) we evaluated if the resulting scaffold allows the reduction of BMP-2 dosage to promote efficient bone repair by providing appropriate guidance cues. Highly porous, anisotropic silk scaffolds were produced, demonstrating good cytocompatibility in vitro and treatment with 10× SBF resulted in efficient surface coating. In vivo, the coated silk scaffolds loaded with a low dose of rhBMP-2 demonstrated significantly improved bone regeneration when compared to the unmineralized scaffold. Overall, our findings show that this simple and cost-efficient technique yields scaffolds that enhance rhBMP-2 mediated bone healing. KW - Tissue Engineering KW - Biomaterials KW - silk scaffold KW - bone regeneration KW - pseudoarthrosis Y1 - VL - 23 IS - 1 / 283 ER - TY - JOUR A1 - Farokhi, Maryam A1 - Aleemardani, Mina A1 - Solouk, Atefeh A1 - Mirzadeh, Hamid A1 - Teuschl, Andreas Herbert A1 - Redl, Heinz T1 - Crosslinking strategies for silk fibroin hydrogels: promising biomedical materials JF - Biomedical Materials N2 - Due to their strong biomimetic potential, silk fibroin (SF) hydrogels are impressive candidates for tissue engineering, due to their tunable mechanical properties, biocompatibility, low immunotoxicity, controllable biodegradability, and a remarkable capacity for biomaterial modification and the realization of a specific molecular structure. The fundamental chemical and physical structure of SF allows its structure to be altered using various crosslinking strategies. The established crosslinking methods enable the formation of three-dimensional (3D) networks under physiological conditions. There are different chemical and physical crosslinking mechanisms available for the generation of SF hydrogels (SFHs). These methods, either chemical or physical, change the structure of SF and improve its mechanical stability, although each method has its advantages and disadvantages. While chemical crosslinking agents guarantee the mechanical strength of SFH through the generation of covalent bonds, they could cause some toxicity, and their usage is not compatible with a cell-friendly technology. On the other hand, physical crosslinking approaches have been implemented in the absence of chemical solvents by the induction of β-sheet conformation in the SF structure. Unfortunately, it is not easy to control the shape and properties of SFHs when using this method. The current review discusses the different crosslinking mechanisms of SFH in detail, in order to support the development of engineered SFHs for biomedical applications. KW - Tissue Engineering KW - hydrogels KW - Biomaterials KW - silk fibroin Y1 - VL - 16 IS - 2 SP - 022004 ER - TY - JOUR A1 - Schanda, Jakob A1 - Keibl, Claudia A1 - Heimel, Patrick A1 - Monforte, Xavier A1 - Feichtinger, Xaver A1 - Teuschl, Andreas A1 - Baierl, Andreas A1 - Muschitz, Christian A1 - Redl, Heinz A1 - Fialka, Christian A1 - Mittermayr, Rainer T1 - Zoledronic Acid Substantially Improves Bone Microarchitecture and Biomechanical Properties After Rotator Cuff Repair in a Rodent Chronic Defect Model JF - Am J Sports Med N2 - Background: Bone mineral density at the humeral head is reduced in patients with chronic rotator cuff tears. Bone loss in the humeral head is associated with repair failure after rotator cuff reconstruction. Bisphosphonates (eg, zoledronic acid) increase bone mineral density. Hypothesis: Zoledronic acid improves bone mineral density of the humeral head and biomechanical properties of the enthesis after reconstruction of chronic rotator cuff tears in rats. Study design: Controlled laboratory study. Methods: A total of 32 male Sprague-Dawley rats underwent unilateral (left) supraspinatus tenotomy with delayed transosseous rotator cuff reconstruction after 3 weeks. All rats were sacrificed 8 weeks after rotator cuff repair. Animals were randomly assigned to 1 of 2 groups. At 1 day after rotator cuff reconstruction, the intervention group was treated with a single subcutaneous dose of zoledronic acid at 100 µg/kg bodyweight, and the control group received 1 mL of subcutaneous saline solution. In 12 animals of each group, micro-computed tomography scans of both shoulders were performed as well as biomechanical testing of the supraspinatus enthesis of both sides. In 4 animals of each group, histological analyses were conducted. Results: In the intervention group, bone volume fraction (bone volume/total volume [BV/TV]) of the operated side was higher at the lateral humeral head (P = .005) and the medial humeral head (P = .010) compared with the control group. Trabecular number on the operated side was higher at the lateral humeral head (P = .004) and the medial humeral head (P = .001) in the intervention group. Maximum load to failure rates on the operated side were higher in the intervention group (P < .001). Cortical thickness positively correlated with higher maximum load to failure rates in the intervention group (r = 0.69; P = .026). Histological assessment revealed increased bone formation in the intervention group. Conclusion: Single-dose therapy of zoledronic acid provided an improvement of bone microarchitecture at the humeral head as well as an increase of maximum load to failure rates after transosseous reconstruction of chronic rotator cuff lesions in rats. Clinical relevance: Zoledronic acid improves bone microarchitecture as well as biomechanical properties after reconstruction of chronic rotator cuff tears in rodents. These results need to be verified in clinical investigations. KW - Tissue Engineering KW - Rotator Cuff Tears Y1 - VL - 2020 Jul IS - 48 (9) SP - 2151 EP - 2160 ER - TY - JOUR A1 - Bachmann, Barbara A1 - Spitz, Sarah A1 - Schädl, Barbara A1 - Teuschl, Andreas A1 - Redl, Heinz A1 - Nürnberger, Sylvia A1 - Ertl, Peter T1 - Stiffness Matters: Fine-Tuned Hydrogel Elasticity Alters Chondrogenic Redifferentiation JF - Froniers in Bioengineering and Biotechnology N2 - Biomechanical cues such as shear stress, stretching, compression, and matrix elasticity are vital in the establishment of next generation physiological in vitro tissue models. Matrix elasticity, for instance, is known to guide stem cell differentiation, influence healing processes and modulate extracellular matrix (ECM) deposition needed for tissue development and maintenance. To better understand the biomechanical effect of matrix elasticity on the formation of articular cartilage analogs in vitro, this study aims at assessing the redifferentiation capacity of primary human chondrocytes in three different hydrogel matrices of predefined matrix elasticities. The hydrogel elasticities were chosen to represent a broad spectrum of tissue stiffness ranging from very soft tissues with a Young's modulus of 1 kPa up to elasticities of 30 kPa, representative of the perichondral-space. In addition, the interplay of matrix elasticity and transforming growth factor beta-3 (TGF-β3) on the redifferentiation of primary human articular chondrocytes was studied by analyzing both qualitative (viability, morphology, histology) and quantitative (RT-qPCR, sGAG, DNA) parameters, crucial to the chondrotypic phenotype. Results show that fibrin hydrogels of 30 kPa Young's modulus best guide chondrocyte redifferentiation resulting in a native-like morphology as well as induces the synthesis of physiologic ECM constituents such as glycosaminoglycans (sGAG) and collagen type II. This comprehensive study sheds light onto the mechanobiological impact of matrix elasticity on formation and maintenance of articular cartilage and thus represents a major step toward meeting the need for advanced in vitro tissue models to study both re- and degeneration of articular cartilage. KW - Tissue Engineering KW - Chondrogenic Redifferentiation KW - Biomaterials Y1 - 2021 VL - 2020 IS - 8 SP - 373 ER - TY - JOUR A1 - Feichtinger, Xaver A1 - Monforte, Xavier A1 - Keibl, Claudia A1 - Hercher, David A1 - Schanda, Jakob A1 - Teuschl, Andreas A1 - Muschitz, Christian A1 - Redl, Heinz A1 - Fialka, Christian A1 - Mittermayr, Rainer T1 - Substantial Biomechanical Improvement by Extracorporeal Shockwave Therapy After Surgical Repair of Rodent Chronic Rotator Cuff Tears. JF - American Journal of Sports Medicine KW - Shockwave Therapy KW - Tissue Engineering KW - Regeneration KW - Surgery Y1 - ER - TY - JOUR A1 - Teuschl, Andreas A1 - Tangl, Stefan A1 - Heimel, Patrick A1 - Schwarze, Uwe Yacine A1 - Monforte, Xavier A1 - Redl, Heinz A1 - Nau, Thomas T1 - Osteointegration of a Novel Silk Fiber-Based ACL Scaffold by Formation of a Ligament-Bone Interface. JF - American Journal of Sports Medicine KW - Tissue Engineering KW - Silk KW - Scaffold KW - ACL Y1 - ER - TY - GEN A1 - Teuschl, Andreas A1 - Schuh, Christina A1 - Weihs, Anna A1 - Guillaume, Olivier A1 - Monforte Vila, Xavier A1 - Redl, Heinz A1 - Kaplan, David A1 - Rünzler, Dominik T1 - Tailoring bioactivity of silk-based biomaterials via delivering and functionalization strategies with fibrinogen/thrombin, plant lectins or laminin KW - Biomaterials KW - Tissue Engineering KW - Silk Y1 - ER - TY - JOUR A1 - Slezak, Paul A1 - Slezak, Cyrill A1 - Hartinger, Joachim A1 - Teuschl, Andreas A1 - Nürnberger, Sylvia A1 - Redl, Heinz A1 - Mittermayr, Rainer T1 - A Low Cost Implantation Model in the Rat That Allows a Spatial Assessment of Angiogenesis. JF - Frontiers in Bioengineering and Biotechnology N2 - There is continual demand for animal models that allow a quantitative assessment of angiogenic properties of biomaterials, therapies, and pharmaceuticals. In its simplest form, this is done by subcutaneous material implantation and subsequent vessel counting which usually omits spatial data. We have refined an implantation model and paired it with a computational analytic routine which outputs not only vessel count but also vessel density, distribution, and vessel penetration depth, that relies on a centric vessel as a reference point. We have successfully validated our model by characterizing the angiogenic potential of a fibrin matrix in conjunction with recombinant human vascular endothelial growth factor (rhVEGF165). The inferior epigastric vascular pedicles of rats were sheathed with silicone tubes, which were subsequently filled with 0.2 ml of fibrin and different doses of rhVEGF165, centrically embedding the vessels. Over 4 weeks, tissue samples were harvested and subsequently immunohistologically stained and computationally analyzed. The model was able to detect variations over the angiogenic potentials of growth factor spiked fibrin matrices. Adding 20 ng of rhVEGF165 resulted in a significant increase in vasculature while 200 ng of rhVEGF165 did not improve vascular growth. Vascularized tissue volume increased during the first week and vascular density increased during the second week. Total vessel count increased significantly and exhibited a peak after 2 weeks which was followed by a resorption of vasculature by week 4. In summary, a simple implantation model to study in vivo vascularization with only a minimal workload attached was enhanced to include morphologic data of the emerging vascular tree. KW - Tissue Engineering KW - Bioreactor KW - Biomaterial Y1 - ER - TY - JOUR A1 - Berkovitch, Yulia A1 - Cohen, Talia A1 - Peled, Eli A1 - Schmidhammer, Robert A1 - Hildner, Florian A1 - Teuschl, Andreas A1 - Wolbank, Susanne A1 - Yelin, Dvir A1 - Redl, Heinz A1 - Seliktar, Dror T1 - Hydrogel composition and laser micropatterning to regulate sciatic nerve regeneration. JF - Journal of Tissue Engineering and Regenerative Medicine N2 - Treatment of peripheral nerve injuries has evolved over the past several decades to include the use of sophisticated new materials endowed with trophic and topographical cues that are essential for in vivo nerve fibre regeneration. In this research, we explored the use of an advanced design strategy for peripheral nerve repair, using biological and semi-synthetic hydrogels that enable controlled environmental stimuli to regenerate neurons and glial cells in a rat sciatic nerve resection model. The provisional nerve growth conduits were composed of either natural fibrin or adducts of synthetic polyethylene glycol and fibrinogen or gelatin. A photo-patterning technique was further applied to these 3D hydrogel biomaterials, in the form of laser-ablated microchannels, to provide contact guidance for unidirectional growth following sciatic nerve injury. We tested the regeneration capacity of subcritical nerve gap injuries in rats treated with photo-patterned materials and compared these with injuries treated with unpatterned hydrogels, either stiff or compliant. Among the factors tested were shear modulus, biological composition, and micropatterning of the materials. The microchannel guidance patterns, combined with appropriately matched degradation and stiffness properties of the material, proved most essential for the uniform tissue propagation during the nerve regeneration process. KW - Tissue Engineering KW - Biomaterials KW - Nerve Regeneration Y1 - SP - 1049 EP - 1061 ER -