title: *Harnessing External Cues: Development and Evaluation of an In Vitro Culture System for Osteochondral Tissue Engineering.
abstract: Over the last decade, engineered structures have been developed for osteochondral (OC) tissue regeneration. While the optimal structure design is yet to be determined, these scaffolds require in vitro evaluation before clinical use. However, the means by which complex scaffolds, such as OC scaffolds, can be tested are limited. Taking advantage of a mesenchymal stem cell's (MSC's) ability to respond to its surrounding we harness external cues, such as the cell's mechanical environment and delivered factors, to create an in vitro culture system for OC tissue engineering with a single cell source on a gradient yet integrated scaffold system. To do this, the effect of hydrogel stiffness on the expression of human MSCs (hMSCs) chondrogenic differentiation was studied using histological analysis. Additionally, hMSCs were also cultured in different combinations of chondrogenic and osteogenic media to develop a co-differentiation media suitable for OC lineage differentiation. A uniquely graded (density-gradient matrix) OC scaffold with a distal cartilage hydrogel phase specifically tailored to support chondrogenic differentiation was cultured using a newly developed "simulated in vivo culture method." The scaffold's culture in co-differentiation media models hMSC infiltration into the scaffold and subsequent differentiation into the distal cartilage and proximal bone layers. Cartilage and bone marker staining along with specific matrix depositions reveal the effect of external cues on the hMSC differentiation. As a result of these studies a model system was developed to study and culture OC scaffolds in vitro.
authors.affiliation: 1 Department of Biomedical Engineering, University of Connecticut , Storrs, Connecticut.|2 Institute for Regenerative Engineering, UCONN Health , Farmington, Connecticut.
authors.forename: Deborah L
authors.initials: DL
authors.lastname: Dorcemus
authors.affiliation: 2 Institute for Regenerative Engineering, UCONN Health , Farmington, Connecticut.
authors.forename: Eve O
authors.initials: EO
authors.lastname: George
authors.affiliation: 3 Center for Regenerative Medicine and Skeletal Development, Department of Reconstructive Sciences, UCONN Health , Farmington, Connecticut.
authors.forename: Caroline N
authors.initials: CN
authors.lastname: Dealy
authors.affiliation: 1 Department of Biomedical Engineering, University of Connecticut , Storrs, Connecticut.|2 Institute for Regenerative Engineering, UCONN Health , Farmington, Connecticut.|4 Orthopaedic Surgery Department, UCONN Health , Farmington, Connecticut.|5 Department of Material Science and Engineering, University of Connecticut , Storrs, Connecticut.
authors.forename: Syam P
authors.initials: SP
authors.lastname: Nukavarapu
mesh_terms: D015415:Biomarkers / Q000378:metabolism; D001842:Bone and Bones / Q000378:metabolism; D002356:Cartilage / Q000187:drug effects / Q000502:physiology; D018929:Cell Culture Techniques / Q000379:methods*; D002454:Cell Differentiation / Q000187:drug effects; D019070:Cell Lineage / Q000187:drug effects; D002469:Cell Separation; D020219:Chondrogenesis / Q000187:drug effects; D005109:Extracellular Matrix / Q000187:drug effects / Q000378:metabolism; D006025:Glycosaminoglycans / Q000378:metabolism; D006801:Humans; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000494:pharmacology; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D010012:Osteogenesis / Q000187:drug effects; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds / Q000737:chemistry
chemical_list: D015415:Biomarkers; D006025:Glycosaminoglycans; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate
keywords: chondrogenesis; co-differentiation media; human mesenchymal stem cell; matrix stiffness; osteogenesis; polymer-gel matrix