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German Congress of Orthopedic and Trauma Surgery (DKOU 2017)

24.10. - 27.10.2017, Berlin

Ex vivo evaluation of cartilage regeneration strategies: Effect of cell type and oxygen concentration in full-thickness defects

Meeting Abstract

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  • presenting/speaker Franziska Ehlicke - University Hospital Wuerzburg, TERM, Wuerzburg, Germany
  • Alexa Buß - University Hospital Wuerzburg, TERM, Wuerzburg, Germany
  • Andrea Schwab - University Hospital Wuerzburg, TERM, Wuerzburg, Germany
  • Heike Walles - University Hospital Wuerzburg, TERM, Translational Center Wuerzburg, Wuerzburg, Germany

Deutscher Kongress für Orthopädie und Unfallchirurgie (DKOU 2017). Berlin, 24.-27.10.2017. Düsseldorf: German Medical Science GMS Publishing House; 2017. DocIN27-351

doi: 10.3205/17dkou065, urn:nbn:de:0183-17dkou0656

Published: October 23, 2017

© 2017 Ehlicke et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 License. See license information at http://creativecommons.org/licenses/by/4.0/.


Outline

Text

Objectives: Degeneration of articular cartilage is a major cause of chronic pain and current treatment options like microfracture or (matrix assisted) autologous chondrocyte implantation result in fibrocartilaginous repair tissue with insufficient mechanical properties. Hence, new therapeutic strategies need to be developed for generation of functional repair tissue. Here we used a recently established ex vivo osteochondral model (XXX) to evaluate the effect of embedded cell type and oxygen concentration on the production of cartilaginous tissue. Due to its clinical relevance, collagen type I hydrogel was chosen as defect filling material for this comparative study.

Methods: Cylindrical osteochondral explants (8mm diameter; 5mm height) were isolated from porcine medial condyles. Full-thickness defects (4mm diameter) were created with a biopsy punch and filled with autologous porcine chondrocytes (pCHON) respectively a mixture of chondrocytes and mesenchymal stem cells (pMIX), embedded in collagen type I hydrogel. Culture was performed for 28 days under static conditions in normoxia (20% O2) respectively hypoxia (2% O2). Samples were analysed histologically for cell viability (live/dead staining) and presence of newly synthesized extracellular matrix proteins. Evaluation of immunohistochemical stainings (Safranin-O-staining, aggrecan, collagen type I, II & X) was done based on the Bern and ICRS II scoring systems with blinded slides. Glycosaminoglycan (GAG) content in hydrogels was also quantified by DMMB assay.

Results and Conclusion: In all approaches, embedded cells remained viable after 28 days culture in ex vivo osteochondral model. Averaged scoring values, obtained from two independent experiments and evaluated by three independent observers ranged from 8.3 (pMIX hypoxia) to 11.8 (pCHON normoxia) [max. possible score: 18]. Higher values were reached in pCHON approaches, compared to pMIX. This finding correlates with GAG content analysis. Referring to our results, oxygen concentration has less influence on overall matrix production than cell type embedded in hydrogel.

The effect of cell type and oxygen concentration on production of cartilaginous tissue was evaluated using collagen type I hydrogel as clinically relevant defect filling material. Best culture conditions will be applied for testing new material-cell-compositions in the ex vivo osteochondral model.

Acknowledgements: The work leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement n° 309962.


References

1.
Schwab A, Meeuwsen A, Ehlicke F, Hansmann J, Mulder L, Smits A, Walles H, Kock L. Ex vivo culture platform for assessment of cartilage repair treatment strategies. ALTEX. 2017;34(2):267-77. DOI: 10.14573/altex.1607111 External link