gms | German Medical Science

German Congress of Orthopaedics and Traumatology (DKOU 2019)

22. - 25.10.2019, Berlin

Intermittent dynamic mechanical stimulation induces recruitment of bone marrow derived-mesenchymal stem/stromal cells

Meeting Abstract

  • presenting/speaker Carolina Gamez - Medical Faculty Mannheim of the University of Heidelberg, Orthopaedics and Trauma Surgery Centre (OUZ), Department for Experimental Orthopaedics and Trauma Surgery, Mannheim, Germany
  • Barbara Schneider-Wald - Medizinische Fakultät Mannheim der Universität Heidelberg, Sektion experimentelle Orthopädie und Unfallchirurgie, Mannheim, Germany
  • Andy Schütte - Sektion experimentelle Orthopädie und Unfallchirurgie, OUZ, Medizin. Fakultät Mannheim der Universität Heidelberg, Mannheim, Germany
  • Michael Mack - Medizinische Fakultät Mannheim der Universität Heidelberg, Sektion experimentelle Orthopädie und Unfallchirurgie, Mannheim, Germany
  • Luisa Hauk - Medizinische Fakultät Mannheim der Universität Heidelberg, Sektion experimentelle Orthopädie und Unfallchirurgie, Mannheim, Germany
  • Arif ul Maula Khan - Medical Research Center (ZMF), Medical Faculty Mannheim of the University of Heidelberg, Mannheim, Germany
  • Karen Bieback - Institute of Transfusion Medicine and Immunology, Medical Faculty Mannheim, Heidelberg University, German Red Cross Blood Service Baden-Württemberg - Hessen, Mannheim, Germany
  • Markus Schwarz - Sektion experimentelle Orthopädie und Unfallchirurgie, OUZ, Medizin. Fakultät Mannheim der Universität Heidelberg, Mannheim, Germany

Deutscher Kongress für Orthopädie und Unfallchirurgie (DKOU 2019). Berlin, 22.-25.10.2019. Düsseldorf: German Medical Science GMS Publishing House; 2019. DocAB36-551

doi: 10.3205/19dkou262, urn:nbn:de:0183-19dkou2621

Published: October 22, 2019

© 2019 Gamez 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: In situ-regeneration of articular cartilage seems to be based on the recruitment of bone marrow-derived mesenchymal stromal cells (BM-MSC) if the subchondral lamella is opened. The process is not fully understood yet, but it can be hypothesized that mechanical stimuli contribute to the recruitment of BM-MSC. The aim of this study was to examine the recruitment in vitro of porcine BM-MSC (pBM-MSC) into a scaffold under intermittent mechanical stimulation in a compression bioreactor.

Methods: A compression bioreactor according to Stoffel et al. [1] was modified to create pressure on a scaffold and a reservoir below housing cells under culture conditions. A piston compressed periodic- and simultaneously the scaffold and a surrounding silicone ring. We applied an intermittent dynamic stimulation for 24 hours consisting of 10% strain (200µm approx.) of the scaffold height, a frequency of 0.3 Hz, and unloaded breaks of 10 s each 10 min. A force sensor located below the cell reservoir measured the loaded force during the stimulation. Data were recorded by a custom-made software using LabView (National Instruments Corporation, U.S).

Functionalized scaffolds made of alginate with and without laminin-521 (LN521) were placed over a suspension of 1.0x105 pBM-MSC. After mechanical stimulation, the recruited cells within the scaffolds were identified in 3D by confocal microscopy after staining with Live/Dead kit (Invitrogen, U.S) for viability and quantified then by the LAS X software [2].

Results and conclusion: We modified a bioreactor able to produce intermittent dynamic compression exerted on hydrogel scaffolds and a cell reservoir underneath with a force amplitude mean of 1.87±1.37 N (min 0.31 N, max 4.42 N). When the piston hit the scaffold again after it had released for 10 s, it induced a higher force-peak with an amplitude of 3.03±1.77 N (min 0.31 N, max 6.50 N), which occurred once for each loading interval.

We found that functionalizing the scaffolds with LN521 enhanced cell recruitment, increasing from 18±6 cells/mm3 to 40±11 cells/mm3. Moreover, cell recruitment was further intensified by the combination of LN521 and the applied mechanical protocol, increasing up to 4 times the number of cells in the loaded LN521-functionalized scaffolds (175±38 cells/mm3) compared to the unloaded control.

Here, we were able to identify and quantify viable cells in the scaffolds recruited from a reservoir below after mechanical stimulation, despite the differences between the replicates. Our results suggest that the applied protocol of intermittent dynamic mechanical stimulation promotes recruitment of pBM-MSC to alginate-LN521 scaffolds.

Acknowledgments: This work has been funded by The Ministry of Science, Research and the Arts of the State of Baden-Württemberg and the Medical Faculty of Mannheim on the University of Heidelberg.


References

1.
Stoffel M, Willenberg W, Azarnoosh M, Fuhrmann-Nelles N, Zhou B, Markert B. Towards bioreactor development with physiological motion control and ist applications. Med Eng Phys. 2017 Jan;39:106-112. DOI: 10.1016/j.medengphy.2016.10.010 External link
2.
Gamez C, et al. Image processing workflow to visualize and quantify MSCs in 3D. In: Deutscher Kongress für Orthopädie und Unfallchirurgie (DKOU 2018). Berlin, 23.-26.10.2018. Düsseldorf: German Medical Science GMS Publishing House; 2018. DocGF16-955. DOI: 10.3205/18dkou491 External link