23 research outputs found

    Chondrogenic priming at reduced cell density enhances cartilage adhesion of equine allogeneic MSCs : a loading sensitive phenomenon in an organ culture study with 180 explants

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    Background: Clinical results of regenerative treatments for osteoarthritis are becoming increasingly significant. However, several questions remain unanswered concerning mesenchymal stem cell (MSC) adhesion and incorporation into cartilage. Methods: To this end, peripheral blood (PB) MSCs were chondrogenically induced and/or stimulated with pulsed electromagnetic fields (PEMFs) for a brief period of time just sufficient to prime differentiation. In an organ culture study, PKH26 labelled MSCs were added at two different cell densities (0.5 x10(6) vs 1.0 x10(6)). In total, 180 explants of six horses (30 per horse) were divided into five groups: no lesion (i), lesion alone (ii), lesion with naive MSCs (iii), lesion with chondrogenically-induced MSCs (iv) and lesion with chondrogenically-induced and PEMF-stimulated MSCs (v). Half of the explants were mechanically loaded and compared with the unloaded equivalents. Within each circumstance, six explants were histologically evaluated at different time points (day 1, 5 and 14). Results: COMP expression was selectively increased by chondrogenic induction (p = 0.0488). PEMF stimulation (1mT for 10 minutes) further augmented COL II expression over induced values (p = 0.0405). On the other hand, MSC markers remained constant over time after induction, indicating a largely predifferentiated state. In the unloaded group, MSCs adhered to the surface in 92.6% of the explants and penetrated into 40.7% of the lesions. On the other hand, physiological loading significantly reduced surface adherence (1.9%) and lesion filling (3.7%) in all the different conditions (p < 0.0001). Remarkably, homogenous cell distribution was characteristic for chondrogenic induced MSCs (+/- PEMFs), whereas clump formation occurred in 39% of uninduced MSC treated cartilage explants. Finally, unloaded explants seeded with a moderately low density of MSCs exhibited greater lesion filling (p = 0.0022) and surface adherence (p = 0.0161) than explants seeded with higher densities of MSCs. In all cases, the overall amount of lesion filling decreased from day 5 to 14 (p = 0.0156). Conclusion: The present study demonstrates that primed chondrogenic induction of MSCs at a lower cell density without loading results in significantly enhanced and homogenous MSC adhesion and incorporation into equine cartilage. Copyright (C) 2015 S. Karger AG, Base

    Comparative study of xeno-free induction protocols for neural differentiation of human dental pulp stem cells in vitro

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    10.1016/j.archoralbio.2019.104572Archives of Oral Biology109104572-10457

    Directionalities of magnetic fields and topographic scaffolds synergise to enhance MSC chondrogenesis

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    10.1016/j.actbio.2020.10.039ACTA BIOMATERIALIA119169-18

    Digital holographic microscopy for the cytomorphological imaging of cells under zero gravity

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    Digital holographic microscopy (DHM) has been gaining interest from cell biology community because of its label free nature and quantitative phase signal output. Besides, fast shutter time, image reconstruction by numerical propagation of the wave fields, and numerical compensation of the aberrations are other intrinsic advantages of this technique that can be explored for harsh imaging conditions. In the frame of this work, a transmission type DHM is developed with a decoupled epifluorescence microscopy mode for cytomorphological monitoring under zero gravity and hyper gravity. With the implemented automatic post processing routines, real time observation of the cell morphology is proven to be feasible under the influence of mechanical disturbances of zero gravity platforms. Post processing of holograms is composed from dynamic numerical compensation of holograms, robust autofocusing and phase image registration. Experiments on live myoblast cells are carried out on two different platforms; random positioning machine (RPM), a ground base microgravity simulation platform, and parabolic flight campaign (PFC), a fixed wing plane flight providing short durations of alternating gravity conditions. Results show clear perinuclear phase increase. During seconds scale microgravity exposure, measurable scale morphological modifications are observed with the accumulated effect of repetitive exposures and short breaks
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