gms | German Medical Science

Deutscher Kongress für Orthopädie und Unfallchirurgie
72. Jahrestagung der Deutschen Gesellschaft für Unfallchirurgie, 94. Tagung der Deutschen Gesellschaft für Orthopädie und Orthopädische Chirurgie und 49. Tagung des Berufsverbandes der Fachärzte für Orthopädie und Unfallchirurgie

22. - 25.10.2008, Berlin

Large-scale gene expression profiling of mesenchymal stem cells attached to smooth tantalum vs. titanium surfaces

Meeting Abstract

  • M. Stiehler - Department of Orthopaedics, University Hospital, Dresden, Germany
  • C. Stiehler - Department of Orthopaedics, University Hospital, Dresden, Germany
  • R. Overall - Center for Regenerative Therapies, Dresden, Germany
  • M. Foss - Interdisciplinary Nanoscience Center (iNANO), Aarhus, Denmark
  • F. Besenbacher - Interdisciplinary Nanoscience Center (iNANO), Aarhus, Denmark
  • M. Kruhøffer - Molecular Diagnostic Laboratory, University Hospital, Aarhus, Denmark
  • M. Kassem - The Molecular Endocrinology Unit, University Hospital, Odense, Denmark
  • K.-P. Günther - Department of Orthopaedics, University Hospital, Dresden, Germany
  • C. Bünger - Orthopaedic Research Laboratory, University Hospital, Aarhus, Denmark

Deutscher Kongress für Orthopädie und Unfallchirurgie. 72. Jahrestagung der Deutschen Gesellschaft für Unfallchirurgie, 94. Tagung der Deutschen Gesellschaft für Orthopädie und Orthopädische Chirurgie, 49. Tagung des Berufsverbandes der Fachärzte für Orthopädie. Berlin, 22.-25.10.2008. Düsseldorf: German Medical Science GMS Publishing House; 2008. DocEF11-129

The electronic version of this article is the complete one and can be found online at: http://www.egms.de/en/meetings/dkou2008/08dkou016.shtml

Published: October 16, 2008

© 2008 Stiehler et al.
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Outline

Text

Introduction: Metallic implants are widely used in orthopedic, oral and maxillofacial surgery. Durable osseous fixation of an implant requires that osteoprogenitor cells attach and adhere to the implant, proliferate, differentiate into osteoblasts, and produce mineralized matrix. We previously observed that human mesenchymal stem cells (MSCs) adherent to smooth tantalum (Ta) surfaces demonstrated superior biocompatibility compared with titanium (Ti) coatings [1]. The aim of the present study was to investigate the interactions between MSCs and smooth surfaces of Ta and Ti by means of whole-genome microarray technology.

Materials and methods: Immortalized human mesenchymal stem cells [2] were cultivated on smooth surfaces of Ta or Ti. Total RNA was extracted after culturing for 1, 2, 4, and 8 days and hybridized to Affymetrix whole-genome microarrays (N=16). Replicate arrays were averaged and the ratios of gene expression by MSCs cultivated on Ta versus Ti coating were calculated. Absolute fold differences were also calculated and lists of upregulated genes were generated. For cluster analysis, Ta/Ti ratios were filtered based on variance. Moreover, gene Ontology (GO) annotation analysis of differentially regulated genes was performed [3].

Results: For both Ta and Ti coatings, the vast majority of genes were upregulated after 4 days of cultivation (Figure 1 [Fig. 1]).

Genes upregulated by MSCs cultivated on Ta coating for 4 days were annotated to the relevant GO terms “cell signaling” and “membrane proteins”, “chondroitin sulfate proteoglycan”, and “response to wounding”. Ti-regulated GO annotation clusters were predominantly transcription-related. By using the K-means clustering algorithm, 10 clusters containing more than 5 genes were identified. Moreover, various genes related to osteogenesis and cell adhesion were upregulated by MSCs exposed to Ta surface.

Conclusion: Microarray analysis of MSCs exposed to smooth metallic surfaces of both Ta and Ti generally showed a huge increase in transcriptional activity after 4 days of cultivation. According to GO annotation analysis Ta coating may induce increased adhesion and earlier differentiation of MSCs compared to Ti surface. This finding makes Ta a promising biocompatible material for bone implants.


References

1.
Stiehler M, et al. J Biomed Mater Res A. 2007 Nov 1. [Epub ahead of print]
2.
Simonsen JL, et al. Nat Biotechnol. 2002;20(6):592-6.
3.
Dennis G, et al. Genome Biol. 2003;4(9):R60.