Abstract
Tissue engineering strategies can be relevant for cartilage repair and regeneration. A collagen matrix was functionalized with the addition of poly-lactic-co-glycolic acid microcarriers (PLGA-MCs) carrying a human Transforming Growth Factor β1 (hTFG-β1) payload, to provide a 3D biomimetic environment with the capacity to direct stem cell commitment towards a chondrogenic phenotype. PLGA-MCs (mean size 3 ± 0.9 μm) were prepared via supercritical emulsion extraction technology and tailored to sustain delivery of payload into the collagen hydrogel for 21 days. PLGA-MCs were coseeded with human Bone Marrow Mesenchymal Stem Cells (hBM-MSCs) in the collagen matrix. Chondrogenic induction was suggested when dynamic perfusion was applied as indicated by transcriptional upregulation of COL2A1 gene (5-fold; p < 0.01) and downregulation of COL1A1 (0.07-fold; p < 0.05) and COL3A1 (0.11-fold; p < 0.05) genes, at day 16, as monitored by qRT-PCR. Histological and quantitative-immunofluorescence (qIF) analysis confirmed cell activity by remodeling the synthetic extracellular matrix when cultured in perfused conditions. Static constructs lacked evidence of chondrogenic specific gene overexpression, which was probably due to a reduced mass exchange, as determined by 3D system Finite Element Modelling (FEM) analysis. Proinflammatory (IL-6, TNF, IL-12A, IL-1β) and anti-inflammatory (IL-10, TGF-β1) cytokine gene expression by hBM-MSC was observed only in dynamic culture (TNF and IL-1β 10-fold, p < 0.001; TGF-β1 4-fold, p < 0.01 at Day 16) confirming the cells’ immunomodulatory activity mainly in relation to their commitment and not due to the synthetic environment. This study supports the use of 3D hydrogel scaffolds, equipped for growth factor controlled delivery, as tissue engineered models for the study of in vitro chondrogenic differentiation and opens clinical perspectives for injectable collagen-based advanced therapy systems.
Highlights
Articular cartilage injuries are a significant health problem due to their poor reparative potential
The present study aimed to evaluate the potential of microcarrier functionalized 3D collagen scaffolds, as a bioengineering tool, for the induction and maintenance of the chondrogenic commitment of human stem cells
SEM image (a) and particle size distribution (b) of PLGA carriers obtained after Supercritical Emulsion Extraction (SEE) process; size distribution data are expressed as volume percentage. hTGF-β1 release profiles expressed as percentage of total load and monitored at 37 ◦ C and 100 rpm by ELISA-based assay; n = 3 (c); hTGF-β1 amount released within each 3D-scaffold loaded with
Summary
Articular cartilage injuries are a significant health problem due to their poor reparative potential. When micro- and nanocarriers are used for controlled delivery of growth factors, an adequate release is promoted by the dynamic environment, whereas in static conditions, reduced mass transfer can decrease the extent of drug release, impacting scaffold efficacy in driving cell commitment [32]. Following these considerations, the present study aimed to evaluate the potential of microcarrier functionalized 3D collagen scaffolds, as a bioengineering tool, for the induction and maintenance of the chondrogenic commitment of human stem cells. Analysis assays will provide indications on cells’ behavior at given time points, whereas cytokines’ gene expression can suggest cells reaction to the 3D environment
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
