Browsing by Author "Prideaux, Matthew"

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    Computational fluid dynamic analysis of bioprinted self-supporting perfused tissue models
    (Wiley, 2020-03) Sego, T. J.; Prideaux, Matthew; Sterner, Jane; McCarthy, Brian Paul; Li, Ping; Bonewald, Lynda F.; Ekser, Burcin; Tovar, Andres; Smith, Lester Jeshua; Anatomy and Cell Biology, School of Medicine
    Natural tissues are incorporated with vasculature, which is further integrated with a cardiovascular system responsible for driving perfusion of nutrient‐rich oxygenated blood through the vasculature to support cell metabolism within most cell‐dense tissues. Since scaffold‐free biofabricated tissues being developed into clinical implants, research models, and pharmaceutical testing platforms should similarly exhibit perfused tissue‐like structures, we generated a generalizable biofabrication method resulting in self‐supporting perfused (SSuPer) tissue constructs incorporated with perfusible microchannels and integrated with the modular FABRICA perfusion bioreactor. As proof of concept, we perfused an MLO‐A5 osteoblast‐based SSuPer tissue in the FABRICA. Although our resulting SSuPer tissue replicated vascularization and perfusion observed in situ, supported its own weight, and stained positively for mineral using Von Kossa staining, our in vitro results indicated that computational fluid dynamics (CFD) should be used to drive future construct design and flow application before further tissue biofabrication and perfusion. We built a CFD model of the SSuPer tissue integrated in the FABRICA and analyzed flow characteristics (net force, pressure distribution, shear stress, and oxygen distribution) through five SSuPer tissue microchannel patterns in two flow directions and at increasing flow rates. Important flow parameters include flow direction, fully developed flow, and tissue microchannel diameters matched and aligned with bioreactor flow channels. We observed that the SSuPer tissue platform is capable of providing direct perfusion to tissue constructs and proper culture conditions (oxygenation, with controllable shear and flow rates), indicating that our approach can be used to biofabricate tissue representing primary tissues and that we can model the system in silico.
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    A Novel Osteogenic Cell Line that Differentiates into GFP‐Tagged Osteocytes and forms Mineral with a Bone‐like Lacunocanalicular Structure
    (Wiley, 2019) Wang, Kun; Le, Lisa; Chun, Brad M.; Tiede-Lewis, LeAnn M.; Shiflett, Lora A.; Prideaux, Matthew; Campos, Richard S.; Veno, Patricia A.; Xie, Yixia; Dusevich, Vladimir; Bonewald, Lynda F.; Dallas, Sarah L.; Anatomy and Cell Biology, IU School of Medicine
    Osteocytes, the most abundant cells in bone, were once thought to be inactive but are now known to have multifunctional roles in bone, including in mechanotransduction, regulation of osteoblast and osteoclast function and phosphate homeostasis. Because osteocytes are embedded in a mineralized matrix and are challenging to study, there is a need for new tools and cell models to understand their biology. We have generated two clonal osteogenic cell lines, OmGFP66 and OmGFP10, by immortalization of primary bone cells from mice expressing a membrane‐targeted GFP driven by the Dmp1‐promoter. One of these clones, OmGFP66, has unique properties compared to previous osteogenic and osteocyte cell models and forms 3‐dimensional mineralized bone‐like structures, containing highly dendritic GFP‐positive osteocytes, embedded in clearly defined lacunae. Confocal and electron microscopy showed that structurally and morphologically, these bone‐like structures resemble bone in vivo, even mimicking the lacunocanalicular ultrastructure and 3D spacing of in vivo osteocytes. In osteogenic conditions, OmGFP66 cells express alkaline phosphatase, produce a mineralized type‐I‐collagen matrix and constitutively express the early osteocyte marker, E11/gp38. With differentiation they express osteocyte markers, Dmp1, Phex, Mepe, Fgf23 and the mature osteocyte marker, Sost. They also express RankL, Opg and Hif1α, and show expected osteocyte responses to PTH, including downregulation of Sost, Dmp1 and Opg and upregulation of RankL and E11/gp38. Live‐cell imaging revealed the dynamic process by which OmGFP66 bone‐like structures form, the motile properties of embedding osteocytes and the integration of osteocyte differentiation with mineralization. The OmGFP10 clone showed an osteocyte gene expression profile similar to OmGFP66, but formed less organized bone nodule‐like mineral, similar to other osteogenic cell models. Not only do these cell lines provide useful new tools for mechanistic and dynamic studies of osteocyte differentiation, function and biomineralization, but OmGFP66 cells have the unique property of modeling osteocytes in their natural bone microenvironment.