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von Witzleben M, Hahn J, Richter RF, de Freitas B, Steyer E, Schütz K, Vater C, Bernhardt A, Elschner C, Gelinsky M. Tailoring the pore design of embroidered structures by melt electrowriting to enhance the cell alignment in scaffold-based tendon reconstruction. BIOMATERIALS ADVANCES 2024; 156:213708. [PMID: 38029698 DOI: 10.1016/j.bioadv.2023.213708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 11/21/2023] [Accepted: 11/23/2023] [Indexed: 12/01/2023]
Abstract
Tissue engineering of ligaments and tendons aims to reproduce the complex and hierarchical tissue structure while meeting the biomechanical and biological requirements. For the first time, the additive manufacturing methods of embroidery technology and melt electrowriting (MEW) were combined to mimic these properties closely. The mechanical benefits of embroidered structures were paired with a superficial micro-scale structure to provide a guide pattern for directional cell growth. An evaluation of several previously reported MEW fiber architectures was performed. The designs with the highest cell orientation of primary dermal fibroblasts were then applied to embroidery structures and subsequently evaluated using human adipose-derived stem cells (AT-MSC). The addition of MEW fibers resulted in the formation of a mechanically robust layer on the embroidered scaffolds, leading to composite structures with mechanical properties comparable to those of the anterior cruciate ligament. Furthermore, the combination of embroidered and MEW structures supports a higher cell orientation of AT-MSC compared to embroidered structures alone. Collagen coating further promoted cell attachment. Thus, these investigations provide a sound basis for the fabrication of heterogeneous and hierarchical synthetic tendon and ligament substitutes.
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Affiliation(s)
- Max von Witzleben
- Technische Universität Dresden, University Hospital Carl Gustav Carus and Faculty of Medicine, Centre for Translational Bone, Joint and Soft Tissue Research, Fetscherstr. 74, 01307 Dresden, Germany
| | - Judith Hahn
- Leibniz-Institut für Polymerforschung Dresden e. V. (IPF), Institute of Polymer Materials, Hohe Str. 6, 01069 Dresden, Germany
| | - Ron F Richter
- Technische Universität Dresden, University Hospital Carl Gustav Carus and Faculty of Medicine, Centre for Translational Bone, Joint and Soft Tissue Research, Fetscherstr. 74, 01307 Dresden, Germany
| | - Bianca de Freitas
- Technische Universität Dresden, University Hospital Carl Gustav Carus and Faculty of Medicine, Centre for Translational Bone, Joint and Soft Tissue Research, Fetscherstr. 74, 01307 Dresden, Germany
| | - Emily Steyer
- Technische Universität Dresden, University Hospital Carl Gustav Carus and Faculty of Medicine, Centre for Translational Bone, Joint and Soft Tissue Research, Fetscherstr. 74, 01307 Dresden, Germany
| | - Kathleen Schütz
- Technische Universität Dresden, University Hospital Carl Gustav Carus and Faculty of Medicine, Centre for Translational Bone, Joint and Soft Tissue Research, Fetscherstr. 74, 01307 Dresden, Germany
| | - Corina Vater
- Technische Universität Dresden, University Hospital Carl Gustav Carus and Faculty of Medicine, Centre for Translational Bone, Joint and Soft Tissue Research, Fetscherstr. 74, 01307 Dresden, Germany
| | - Anne Bernhardt
- Technische Universität Dresden, University Hospital Carl Gustav Carus and Faculty of Medicine, Centre for Translational Bone, Joint and Soft Tissue Research, Fetscherstr. 74, 01307 Dresden, Germany
| | - Cindy Elschner
- Leibniz-Institut für Polymerforschung Dresden e. V. (IPF), Institute of Polymer Materials, Hohe Str. 6, 01069 Dresden, Germany
| | - Michael Gelinsky
- Technische Universität Dresden, University Hospital Carl Gustav Carus and Faculty of Medicine, Centre for Translational Bone, Joint and Soft Tissue Research, Fetscherstr. 74, 01307 Dresden, Germany.
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Gögele C, Hahn J, Schulze-Tanzil G. Anatomical Tissue Engineering of the Anterior Cruciate Ligament Entheses. Int J Mol Sci 2023; 24:ijms24119745. [PMID: 37298698 DOI: 10.3390/ijms24119745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 05/23/2023] [Accepted: 05/26/2023] [Indexed: 06/12/2023] Open
Abstract
The firm integration of anterior cruciate ligament (ACL) grafts into bones remains the most demanding challenge in ACL reconstruction, since graft loosening means graft failure. For a functional-tissue-engineered ACL substitute to be realized in future, robust bone attachment sites (entheses) have to be re-established. The latter comprise four tissue compartments (ligament, non-calcified and calcified fibrocartilage, separated by the tidemark, bone) forming a histological and biomechanical gradient at the attachment interface between the ACL and bone. The ACL enthesis is surrounded by the synovium and exposed to the intra-articular micromilieu. This review will picture and explain the peculiarities of these synovioentheseal complexes at the femoral and tibial attachment sites based on published data. Using this, emerging tissue engineering (TE) strategies addressing them will be discussed. Several material composites (e.g., polycaprolactone and silk fibroin) and manufacturing techniques (e.g., three-dimensional-/bio-printing, electrospinning, braiding and embroidering) have been applied to create zonal cell carriers (bi- or triphasic scaffolds) mimicking the ACL enthesis tissue gradients with appropriate topological parameters for zones. Functionalized or bioactive materials (e.g., collagen, tricalcium phosphate, hydroxyapatite and bioactive glass (BG)) or growth factors (e.g., bone morphogenetic proteins [BMP]-2) have been integrated to achieve the zone-dependent differentiation of precursor cells. However, the ACL entheses comprise individual (loading history) asymmetric and polar histoarchitectures. They result from the unique biomechanical microenvironment of overlapping tensile, compressive and shear forces involved in enthesis formation, maturation and maintenance. This review should provide a road map of key parameters to be considered in future in ACL interface TE approaches.
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Affiliation(s)
- Clemens Gögele
- Institute of Anatomy and Cell Biology, Paracelsus Medical University, Nuremberg and Salzburg, Prof. Ernst Nathan Str. 1, 90419 Nuremberg, Germany
| | - Judith Hahn
- Workgroup BioEngineering, Department Materials Engineering, Institute of Polymers Materials, Leibniz-Institut für Polymerforschung Dresden e.V. (IPF), Hohe Straße 6, 01069 Dresden, Germany
| | - Gundula Schulze-Tanzil
- Institute of Anatomy and Cell Biology, Paracelsus Medical University, Nuremberg and Salzburg, Prof. Ernst Nathan Str. 1, 90419 Nuremberg, Germany
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Gögele C, Vogt J, Hahn J, Breier A, Bernhardt R, Meyer M, Schröpfer M, Schäfer-Eckart K, Schulze-Tanzil G. Co-Culture of Mesenchymal Stem Cells and Ligamentocytes on Triphasic Embroidered Poly(L-lactide-co-ε-caprolactone) and Polylactic Acid Scaffolds for Anterior Cruciate Ligament Enthesis Tissue Engineering. Int J Mol Sci 2023; 24:ijms24076714. [PMID: 37047686 PMCID: PMC10095212 DOI: 10.3390/ijms24076714] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 03/26/2023] [Accepted: 03/28/2023] [Indexed: 04/07/2023] Open
Abstract
Successful anterior cruciate ligament (ACL) reconstructions strive for a firm bone-ligament integration. With the aim to establish an enthesis-like construct, embroidered functionalized scaffolds were colonized with spheroids of osteogenically differentiated human mesenchymal stem cells (hMSCs) and lapine (l) ACL fibroblasts in this study. These triphasic poly(L-lactide-co-ε-caprolactone) and polylactic acid (P(LA-CL)/PLA) scaffolds with a bone-, a fibrocartilage transition- and a ligament zone were colonized with spheroids directly after assembly (DC) or with 14-day pre-cultured lACL fibroblast and 14-day osteogenically differentiated hMSCs spheroids (=longer pre-cultivation, LC). The scaffolds with co-cultures were cultured for 14 days. Cell vitality, DNA and sulfated glycosaminoglycan (sGAG) contents were determined. The relative gene expressions of collagen types I and X, Mohawk, Tenascin C and runt-related protein (RUNX) 2 were analyzed. Compared to the lACL spheroids, those with hMSCs adhered more rapidly. Vimentin and collagen type I immunoreactivity were mainly detected in the hMSCs colonizing the bone zone. The DNA content was higher in the DC than in LC whereas the sGAG content was higher in LC. The gene expression of ECM components and transcription factors depended on cell type and pre-culturing condition. Zonal colonization of triphasic scaffolds using spheroids is possible, offering a novel approach for enthesis tissue engineering.
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Affiliation(s)
- Clemens Gögele
- Institute of Anatomy and Cell Biology, Paracelsus Medical University, Nuremberg and Salzburg, Prof. Ernst Nathan Str. 1, 90419 Nuremberg, Germany
| | - Julia Vogt
- Institute of Anatomy and Cell Biology, Paracelsus Medical University, Nuremberg and Salzburg, Prof. Ernst Nathan Str. 1, 90419 Nuremberg, Germany
| | - Judith Hahn
- Department Materials Engineering, Institute of Polymers Materials, Leibniz-Institut für Polymerforschung Dresden e.V. (IPF), Hohe Straße 6, 01069 Dresden, Germany
| | - Annette Breier
- Department Materials Engineering, Institute of Polymers Materials, Leibniz-Institut für Polymerforschung Dresden e.V. (IPF), Hohe Straße 6, 01069 Dresden, Germany
| | - Ricardo Bernhardt
- Department Materials Engineering, Institute of Polymers Materials, Leibniz-Institut für Polymerforschung Dresden e.V. (IPF), Hohe Straße 6, 01069 Dresden, Germany
| | - Michael Meyer
- FILK Freiberg Institute gGmbH (FILK), Meißner Ring 1-5, 09599 Freiberg, Germany
| | - Michaela Schröpfer
- FILK Freiberg Institute gGmbH (FILK), Meißner Ring 1-5, 09599 Freiberg, Germany
| | - Kerstin Schäfer-Eckart
- Bone Marrow Transplantation Unit, Medizinische Klinik 5, Klinikum Nürnberg, 90419 Nuremberg, Germany
| | - Gundula Schulze-Tanzil
- Institute of Anatomy and Cell Biology, Paracelsus Medical University, Nuremberg and Salzburg, Prof. Ernst Nathan Str. 1, 90419 Nuremberg, Germany
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Kokozidou M, Gögele C, Pirrung F, Hammer N, Werner C, Kohl B, Hahn J, Breier A, Schröpfer M, Meyer M, Schulze-Tanzil G. In vivo ligamentogenesis in embroidered poly(lactic-co-ε-caprolactone) / polylactic acid scaffolds functionalized by fluorination and hexamethylene diisocyanate cross-linked collagen foams. Histochem Cell Biol 2023; 159:275-292. [PMID: 36309635 PMCID: PMC10006054 DOI: 10.1007/s00418-022-02156-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/16/2022] [Indexed: 11/30/2022]
Abstract
Although autografts represent the gold standard for anterior cruciate ligament (ACL) reconstruction, tissue-engineered ACLs provide a prospect to minimize donor site morbidity and limited graft availability. This study characterizes the ligamentogenesis in embroidered poly(L-lactide-co-ε-caprolactone) (P(LA-CL)) / polylactic acid (PLA) constructs using a dynamic nude mice xenograft model. (P(LA-CL))/PLA scaffolds remained either untreated (co) or were functionalized by gas fluorination (F), collagen foam cross-linked with hexamethylene diisocyanate (HMDI) (coll), or F combined with the foam (F + coll). Cell-free constructs or those seeded for 1 week with lapine ACL ligamentocytes were implanted into nude mice for 12 weeks. Following explantation, cell vitality and content, histo(patho)logy of scaffolds (including organs: liver, kidney, spleen), sulphated glycosaminoglycan (sGAG) contents and biomechanical properties were assessed.Scaffolds did not affect mice weight development and organs, indicating no organ toxicity. Moreover, scaffolds maintained their size and shape and reflected a high cell viability prior to and following implantation. Coll or F + coll scaffolds seeded with cells yielded superior macroscopic properties compared to the controls. Mild signs of inflammation (foreign-body giant cells and hyperemia) were limited to scaffolds without collagen. Microscopical score values and sGAG content did not differ significantly. Although remaining stable after explantation, elastic modulus, maximum force, tensile strength and strain at Fmax were significantly lower in explanted scaffolds compared to those before implantation, with no significant differences between scaffold subtypes, except for a higher maximum force in F + coll compared with F samples (in vivo). Scaffold functionalization with fluorinated collagen foam provides a promising approach for ACL tissue engineering. a Lapine anterior cruciate ligament (LACL): red arrow, posterior cruciate ligament: yellow arrow. Medial anterior meniscotibial ligament: black arrow. b Explant culture to isolate LACL fibroblasts. c Scaffold variants: co: controls; F: functionalization by gas-phase fluorination; coll: collagen foam cross-linked with hexamethylene diisocyanate (HMDI). c1-2 Embroidery pattern of the scaffolds. d Scaffolds were seeded with LACL fibroblasts using a dynamical culturing approach as depicted. e Scaffolds were implanted subnuchally into nude mice, fixed at the nuchal ligament and sacrospinal muscle tendons. f Two weeks after implantation. g Summary of analyses performed. Scale bars 1 cm (b, d), 0.5 cm (c). (sketches drawn by G.S.-T. using Krita 4.1.7 [Krita foundation, The Netherlands]).
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Affiliation(s)
- Maria Kokozidou
- Institute of Anatomy and Cell Biology, Paracelsus Medical University, Nuremberg and Salzburg, Prof. Ernst Nathan Str. 1, 90419, Nuremberg, Germany
| | - Clemens Gögele
- Institute of Anatomy and Cell Biology, Paracelsus Medical University, Nuremberg and Salzburg, Prof. Ernst Nathan Str. 1, 90419, Nuremberg, Germany.,Department of Biosciences and Medical Biology, Paris Lodron University Salzburg, Hellbrunnerstraße 34, 5020, Salzburg, Austria
| | - Felix Pirrung
- Division of Macroscopic and Clinical Anatomy, Gottfried Schatz Research Center, Medical University of Graz, Harrachgasse 21, 8010, Graz, Austria
| | - Niels Hammer
- Division of Macroscopic and Clinical Anatomy, Gottfried Schatz Research Center, Medical University of Graz, Harrachgasse 21, 8010, Graz, Austria.,Department of Orthopedic and Trauma Surgery, University of Leipzig, Leipzig, Germany.,Fraunhofer Institute for Machine Tools and Forming Technology IWU, Nöthnitzer Straße 44, 01187, Dresden, Germany
| | - Christian Werner
- Institute of Anatomy and Cell Biology, Paracelsus Medical University, Nuremberg and Salzburg, Prof. Ernst Nathan Str. 1, 90419, Nuremberg, Germany
| | - Benjamin Kohl
- Department of Traumatology and Reconstructive Surgery, Charité -Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität Zu Berlin, Campus Benjamin Franklin, Hindenburgdamm 30, 12203, Berlin, Germany
| | - Judith Hahn
- Workgroup Bio-Engineering, Department Materials Engineering, Leibniz-Institut für Polymerforschung Dresden e. V. (IPF), Institute Polymers Materials, Hohe Straße 6, 01069, Dresden, Germany
| | - Annette Breier
- Workgroup Bio-Engineering, Department Materials Engineering, Leibniz-Institut für Polymerforschung Dresden e. V. (IPF), Institute Polymers Materials, Hohe Straße 6, 01069, Dresden, Germany
| | - Michaela Schröpfer
- FILK Freiberg Institute gGmbH (FILK), Meißner Ring 1-5, 09599, Freiberg, Germany
| | - Michael Meyer
- FILK Freiberg Institute gGmbH (FILK), Meißner Ring 1-5, 09599, Freiberg, Germany
| | - Gundula Schulze-Tanzil
- Institute of Anatomy and Cell Biology, Paracelsus Medical University, Nuremberg and Salzburg, Prof. Ernst Nathan Str. 1, 90419, Nuremberg, Germany.
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Schulze-Tanzil GG. Healing of Ligaments and Tendons: Tissue Engineering and Models. Int J Mol Sci 2022; 23:ijms232415503. [PMID: 36555147 PMCID: PMC9778817 DOI: 10.3390/ijms232415503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 11/30/2022] [Indexed: 12/13/2022] Open
Abstract
The aim of this Special Issue is to summarize the latest developments in tendon/ligament research and tissue engineering (TE), providing helpful approaches for future tendon/ligament reconstruction (Figure 1) [...].
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Affiliation(s)
- Gundula Gesine Schulze-Tanzil
- Institute of Anatomy and Cell Biology, Paracelsus Medical University, Nuremberg and Salzburg, Prof. Ernst Nathan Str. 1, 90419 Nuremberg, Germany
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Sha Y, Zhang B, Chen L, Hong H, Chi Q. Mechano Growth Factor Accelerates ACL Repair and Improves Cell Mobility of Mechanically Injured Human ACL Fibroblasts by Targeting Rac1-PAK1/2 and RhoA-ROCK1 Pathways. Int J Mol Sci 2022; 23:ijms23084331. [PMID: 35457148 PMCID: PMC9026312 DOI: 10.3390/ijms23084331] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 04/10/2022] [Accepted: 04/11/2022] [Indexed: 02/04/2023] Open
Abstract
Exceeded mechanical stress leads to a sublethal injury to anterior cruciate ligament (ACL) fibroblasts, and it will hinder cell mobility and ACL regeneration, and even induce osteoarthritis. The mechano growth factor (MGF) could be responsible for mechanical stress and weakening its negative effects on cell physiological behaviors. In this study, effects of MGF on cell mobility and relevant molecules expression in injured ACL fibroblasts were detected. After an injurious mechanical stretch, the analysis carried out, at 0 and 24 h, respectively, showed that the cell area, roundness, migration, and adhesion of ACL fibroblasts were reduced. MGF (10, 100 ng/mL) treatment could improve cell area, roundness and promote cell migration and adhesion capacity compared with the injured group without MGF. Further study indicated that cell mobility-relevant molecules (PAK1/2, Cdc42, Rac1, RhoA, and ROCK1) expression in ACL fibroblasts was down-regulated at 0 or 24 h after injurious stretch (except Rac1 and RhoA at 0 h). Similarly, MGF improved cell mobility-relevant molecule expression, especially the ROCK1 expression level in ACL fibroblasts at 0 or 24 h after injurious stretch. Protein expression of ROCK1 in injured ACL fibroblasts was also reduced and could be recovered by MGF treatment. In a rabbit partial ACL transection (ACLT) model, ACL exhibited poor regenerative capacity in collagen and extracellular matrix (ECM) synthesis after partial ACLT for 2 or 4 weeks, and MGF remarkably accelerated ACL regeneration and restored its mechanical loading capacity after partial ACLT for four weeks. Our findings suggest that MGF weakens the effects of pathological stress on cell mobility of ACL fibroblasts and accelerates ACL repair, and might be applied as a future treatment approach to ACL rupture in the clinic.
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Affiliation(s)
- Yongqiang Sha
- Center for Precision Medicine, School of Medicine and School of Biomedical Sciences, Huaqiao University, Xiamen 361021, China; (B.Z.); (L.C.); (H.H.)
- National Innovation and Attracting Talents “111” Base, Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400030, China;
- Correspondence:
| | - Beibei Zhang
- Center for Precision Medicine, School of Medicine and School of Biomedical Sciences, Huaqiao University, Xiamen 361021, China; (B.Z.); (L.C.); (H.H.)
| | - Liping Chen
- Center for Precision Medicine, School of Medicine and School of Biomedical Sciences, Huaqiao University, Xiamen 361021, China; (B.Z.); (L.C.); (H.H.)
| | - Huhai Hong
- Center for Precision Medicine, School of Medicine and School of Biomedical Sciences, Huaqiao University, Xiamen 361021, China; (B.Z.); (L.C.); (H.H.)
| | - Qingjia Chi
- National Innovation and Attracting Talents “111” Base, Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400030, China;
- Department of Mechanics and Engineering Structure, Hubei Key Laboratory of Theory and Application of Advanced Materials Mechanics, Wuhan University of Technology, Wuhan 430070, China
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Zahn I, Braun T, Gögele C, Schulze-Tanzil G. Minispheroids as a Tool for Ligament Tissue Engineering: Do the Self-Assembly Techniques and Spheroid Dimensions Influence the Cruciate Ligamentocyte Phenotype? Int J Mol Sci 2021; 22:11011. [PMID: 34681672 PMCID: PMC8537246 DOI: 10.3390/ijms222011011] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 09/29/2021] [Accepted: 10/05/2021] [Indexed: 12/14/2022] Open
Abstract
Spheroid culture might stabilize the ligamentocyte phenotype. Therefore, the phenotype of lapine cruciate ligamentocyte (L-CLs) minispheroids prepared either by hanging drop (HD) method or by using a novel spheroid plate (SP) and the option of methyl cellulose (MC) for tuning spheroid formation was tested. A total of 250 and 1000 L-CLs per spheroid were seeded as HDs or on an SP before performing cell viability assay, morphometry, gene expression (qRT-PCR) and protein immunolocalization after 7 (HD/SP) and 14 (SP) days. Stable and viable spheroids of both sizes could be produced with both methods, but more rapidly with SP. MC accelerated the formation of round spheroids (HD). Their circular areas decreased significantly during culturing. After 7 days, the diameters of HD-derived spheroids were significantly larger compared to those harvested from the SP, with a tendency of lower circularity suggesting an ellipsoid shape. Gene expression of decorin increased significantly after 7 days (HD, similar trend in SP), tenascin C tended to increase after 7 (HD/SP) and 14 days (SP), whereas collagen type 1 decreased (HD/SP) compared to the monolayer control. The cruciate ligament extracellular matrix components could be localized in all mini-spheroids, confirming their conserved expression profile and their suitability for ligament tissue engineering.
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Affiliation(s)
- Ingrid Zahn
- Institute of Anatomy and Cell Biology, Paracelsus Medical University, Nuremberg and Salzburg, Prof. Ernst Nathan Str.1, 90419 Nuremberg, Germany; (I.Z.); (T.B.); (C.G.)
- Institute of Functional and Clinical Anatomy, Friedrich Alexander University, Erlangen-Nuremberg, Universitätsstraße 19, 91054 Erlangen, Germany
- Department of Applied Chemistry, Nuremberg Institute of Technology Georg Simon Ohm, Keßlerplatz 12, 90489 Nuremberg, Germany
| | - Tobias Braun
- Institute of Anatomy and Cell Biology, Paracelsus Medical University, Nuremberg and Salzburg, Prof. Ernst Nathan Str.1, 90419 Nuremberg, Germany; (I.Z.); (T.B.); (C.G.)
- Department of Applied Chemistry, Nuremberg Institute of Technology Georg Simon Ohm, Keßlerplatz 12, 90489 Nuremberg, Germany
- Department of Cardiac Surgery (Cardiovascular Center), Klinikum Nürnberg Süd, Breslauer Str. 201, 90471 Nuremberg, Germany
| | - Clemens Gögele
- Institute of Anatomy and Cell Biology, Paracelsus Medical University, Nuremberg and Salzburg, Prof. Ernst Nathan Str.1, 90419 Nuremberg, Germany; (I.Z.); (T.B.); (C.G.)
- Department of Biosciences, Paris Lodron University of Salzburg, Hellbrunnerstr 34, 5020 Salzburg, Austria
| | - Gundula Schulze-Tanzil
- Institute of Anatomy and Cell Biology, Paracelsus Medical University, Nuremberg and Salzburg, Prof. Ernst Nathan Str.1, 90419 Nuremberg, Germany; (I.Z.); (T.B.); (C.G.)
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