Modeling of the Human Bone Environment: Mechanical Stimuli Guide Mesenchymal Stem Cell–Extracellular Matrix Interactions

Abstract

In bone tissue engineering, the design of in vitro models able to recreate both the chemical composition, the structural architecture, and the overall mechanical environment of the native tissue is still often neglected. In this study, we apply a bioreactor system where human bone-marrow hMSCs are seeded in human femoral head-derived decellularized bone scaffolds and subjected to dynamic culture, i.e., shear stress induced by continuous cell culture medium perfusion at 1.7 mL/min flow rate and compressive stress by 10% uniaxial load at 1 Hz for 1 h per day. In silico modeling revealed that continuous medium flow generates a mean shear stress of 8.5 mPa sensed by hMSCs seeded on 3D bone scaffolds. Experimentally, both dynamic conditions improved cell repopulation within the scaffold and boosted ECM production compared with static controls. Early response of hMSCs to mechanical stimuli comprises evident cell shape changes and stronger integrin-mediated adhesion to the matrix. Stress-induced Col6 and SPP1 gene expression suggests an early hMSC commitment towards osteogenic lineage independent of Runx2 signaling. This study provides a foundation for exploring the early effects of external mechanical stimuli on hMSC behavior in a biologically meaningful in vitro environment, opening new opportunities to study bone development, remodeling, and pathologies.

Preservation of the naïve features of mesenchymal stromal cells in vitro: Comparison of cell- and bone-derived decellularized extracellular matrix

“…Decellularized bone scaffolds were obtained from human trabecular femoral head specimens (permission number: 187/18, University of Wuerzburg ethics committee), as previously described in. 25 , 45 Briefly, freshly thawed samples (kept at −20°C for no more than 4 months after surgery) were precisely cut in 3 mm thick slides using an electric diamond band saw (300 Exakt D64, Walter Messner, Germany) to ensure homogeneous penetration of washing solutions through the complete sample volume. Blood and residual fat material were removed by several washing cycles in water and a chloroform (288306, Sigma-Aldrich) and methanol (8388.6, Carl-Roth) mix solution.…”

“…This becomes even more evident when one considers cell-ECM communication (or relations) as bidirectional interactions, wherein cells constantly rebuild their surroundings, thus untimely influencing their own fate. 23 – 25 It follows from this that great efforts have been made in the field of tissue engineering using advanced biomaterials to recapitulate these unique niche conditions in ex vivo culture. The key universal goal is to avoid the persistently observed “ageing” process of cells during long-lasting in vitro cultivation – that is, cell shape change, and significantly decreased colony-forming and differentiation potential.…”

Bioengineered Living Bone Grafts—A Concise Review on Bioreactors and Production Techniques In Vitro

“…Consequently, the nitric oxide promoted the osteogenesis process by regulation of canonical Wnt/β-catenin signaling. In another study, continuous medium flow with a mean shear stress equal to 8.5 mPa improved the proliferation of human BMDSCs and increased ECM production compared to control cells cultured in static conditions [78]. In turn, Yamada et al [79] showed that during the perfusion (shear stress distribution ranging from 0.20 mPa to 0.40 mPa), cell proliferation on polyester-based scaffolds was significantly inhibited.…”

In Vivo Bone Tissue Engineering Strategies: Advances and Prospects

“…Perfusion bioreactors consist of a media reservoir, a pump, a flow perfusion chambers, an oxygenator, a tubing circuit, and a waste tank. Several authors reported successful use of perfusion bioreactors for BTE purposes [ 163 , 164 , 165 ]. Liu et al presented results of using porcine decellularized native bone seeded with human smooth muscle cells and human umbilical vein endothelial cells within a perfusion bioreactor.…”

“…Ressler et al confirmed osteogenic differentiation using a composite Calcium phosphate/Hydroxyapatite scaffold seeded with human mesenchymal stem cells in a perfusion bioreactor [ 164 ]. Pereira et al used a custom-made perfusion bioreactor system and decellularized human bone scaffolds seeded with human bone marrow-derived mesenchymal stem cells [ 165 ].…”