A decellularized human bone scaffold under dynamic incubation as model of the skeletal progenitor cell niche

Introduction The mobilization and activation of mesenchymal stem/stromal cells (MSCs) is strictly controlled by complex interactions with the close physical and chemical environment. We here aim to develop a dynamic decellularized bone model where structural, mechanical and biological features of native tissue are resembled.

Methods Human femoral heads were collected after patient’s total hip arthroplasty with informed consent and agreement of the local ethics committee (187/18). Bone slices of 3 mm thickness were decellularized and decalcified. Cylindrical-shaped scaffolds with 10 mm diameter were prepared. Information of the decellularized scaffold structure was obtained by micro computed tomography (µCT). MSCs were isolated from human bone marrow of femoral heads and 5.5 x 105 cells per scaffold were seeded in a volume of 50 µL. Cells were let to adhere for 3 h in an untreated plate before scaffolds were transferred to the bioreactor [1]. A perfusion rate of 2.4 mL/min was implemented and maintained for 1 to 10 days. The culture media was changed every 2 days. At the endpoint of the experiment cell viability and distribution as well as osteogenic differentiation (activity of alkaline phosphatase [ALP] and gene expression) were analyzed.

Results The here established protocol yielded reproducibly homogenous decellularized and decalcified bone scaffolds. The conservation of the native human bone structure was illustrated by µCT analysis. Viability of MSCs was confirmed. Dynamic culture of scaffolds improved cell viability and resulted in a more homogenous cell distribution. Osteogenic differentiation of MSCs was supported in both static and dynamic cultures.

Discussion We here established human decellularized and decalcified bone scaffolds as suitable 3 D culture system for MSCs. Future studies will investigate the MSC phenotype and migration behavior in the scaffolds under dynamic conditions.

Keywords Mesenchymal Stem Cells, Skeletal Niche, Decellularization, 3 D Models, Perfusion

Korrespondenzadresse Rita Pereira, University Clinics Wuerzburg, IZKF Research Group Tissue Regeneration in Musculoskeletal Diseases, Röntgenring 11, 97070 Würzburg, Deutschland, Germany

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