RESUMEN

Scaffold plays a critical role in stem cell differentiation and tissue regeneration. Composite scaffolds composed of bacterial cellulose (BC) and collagen (Col) in different ratios (1:1, 3:1, 5:1) were fabricated in this study. The composite scaffolds exhibit a well-organized interconnected porous structure, significantly better physical stability than Col scaffold, and more water uptake up to 400%. They were also favorable with cell attachment and growth. After osteogenic induction of umbilical cord blood derived mesenchymal stem cells (UCB-MSCs) for 3 weeks, we found more up-regulated osteogenic markers (collagen type 1, osteocalcin, bone sialoprotein) and significantly elevated proteins and calcium deposition, particularly with BC/Col (5:1) scaffold. When PKH-26 pre-labelled MSC-loaded scaffolds were subcutaneously transplanted in a mouse model, they showed many PKH-26-labelled cells and positive signals of α-smooth muscle actin, for neovascularization in the BC/Col (5:1). The current work demonstrates that our BC/Col composites may be promising as a bone tissue-engineered scaffold.

Asunto(s)

Celulosa/química , Colágeno/química , Gluconacetobacter xylinus/metabolismo , Ingeniería de Tejidos/métodos , Andamios del Tejido/química , Animales , Regeneración Ósea/efectos de los fármacos , Diferenciación Celular/efectos de los fármacos , Celulosa/uso terapéutico , Colágeno/uso terapéutico , Humanos , Células Madre Mesenquimatosas/efectos de los fármacos , Ratones , Células 3T3 NIH , Osteogénesis/efectos de los fármacos

RESUMEN

BACKGROUND: Formation of mature and functional articular cartilage is still challenging in cartilage tissue engineering. This study investigates the potential of using heparin-grafted decellularized extracellular matrix (ECM) as a novel growth factor delivery platform towards human placenta-derived mesenchymal stem cells (hPMSCs) chondrogenic differentiation. Human fibroblast-derived extracellular matrix (hFDM) is naturally obtained from in vitro-cultured human lung fibroblasts via a mild decellularization process. hFDM was then conjugated with heparin via N-(3-Dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC) chemistry and subject to transforming growth factor (TGF)-ß1 immobilization. Once heparin grafted-hFDM (hFDM-hep) and hPMSCs were co-embedded into collagen gel, they were examined for in vitro and in vivo chondrogenesis of hPMSCs for 4 weeks. RESULTS: We identified heparin moieties on hFDM via toluidine blue O assay and Fourier transform infrared spectroscopy, respectively. We found out that collagen spheroids containing hFDM-hep and TGF-ß1 exhibited a sustained release of growth factor for 28 days in vitro. Chondrogenesis of hPMSCs in vitro was supported by accumulated glycosaminoglycan (GAG) content and upregulated chondrogenic specific markers (collagen II, aggrecan, Sox9). Meanwhile, PKH26 - labeled hPMSCs incorporated collagen with either hFDM or hFDM-hep was pre-conditioned in a chondrogenic media for 3 days and subcutaneously implanted in the back of nude mice for 4 weeks. The implanted collagen spheroids containing both hPMSCs and hFDM-hep retained more viable hPMSCs and showed higher level of chondrogenic differentiation, based on immunostaining of collagen type II over collagen alone or Col/hFDM group. In addition, histological examination showed more positive signals of GAG via Safranin-O staining. CONCLUSION: TGF-ß1-immobilized hFDM-hep can provide an appropriate microenvironment for chondrogenic differentiation of hPMSCs in 3D collagen spheroid.