Biodegradable ECM-coated PCL microcarriers support scalable human early MSC expansion and in vivo bone formation.
BACKGROUND AIMS
Human mesenchymal stromal cells or marrow stromal cells (MSCs) are of great interest for bone healing due to their multi-potency and trophic effects. However, traditional MSC expansion methods using 2-dimensional monolayer (MNL) flasks or cell stacks are limited by labor-intensive handling, lack of scalability, the need for enzymatic cell harvesting and the need for attachment to a scaffold before in vivo delivery. Here, we present a biodegradable microcarrier and MSC bioprocessing system that may overcome the abovementioned challenges.


METHODS
We cultured human early MSCs (heMSCs) on biodegradable polycaprolactone microcarriers (PCL MCs) coated with extracellular matrix (ECM) and evaluated the in vitro osteogenic differentiation and in vivo bone formation capacity of ECM-coated PCL MC-bound heMSCs compared with conventional MNL-cultured cells.


RESULTS
We found that heMSCs proliferate well on PCL MCs coated with a fibronectin, poly-l-lysine, and fibronectin (FN+PLL+FN) coating (cPCL MCs). During in vitro osteogenic induction, heMSCs cultured on cPCL MCs displayed a 68% increase in specific calcium deposition compared with cultures on MNL. In a mouse ectopic mineralization model, bone mass was equivalent for MNL-expanded and cPCL MC-bound heMSC implants but higher in both cases when compared with cell-free cPCL MC implants at 16 weeks post-implantation. In summary, compared with MNL cultures, biodegradable MC MSC cultures provide the benefits of large-scale expansion of cells and can be delivered in vivo, thereby eliminating the need for cell harvesting and use of scaffolds for cell delivery. These results highlight the promise of delivering heMSCs cultured on cPCL MCs for bone applications.
['Shekaran|Asha|A|', 'Lam|Alan|A|', 'Sim|Eileen|E|', 'Jialing|Lee|L|', 'Jian|Li|L|', 'Wen|Jessica Toh Pei|JT|', 'Chan|Jerry Kok Yen|JK|', 'Choolani|Mahesh|M|', 'Reuveny|Shaul|S|', 'Birch|William|W|', 'Oh|Steve|S|']
D020341:Absorbable Implants D000818:Animals D001861:Bone Regeneration D018929:Cell Culture Techniques D002454:Cell Differentiation D049109:Cell Proliferation D002478:Cells, Cultured D005109:Extracellular Matrix D006801:Humans D059630:Mesenchymal Stem Cells D051379:Mice D055616:Microtechnology D008904:Miniaturization D010012:Osteogenesis D011091:Polyesters D054457:Tissue Scaffolds
PCL microcarriers bone formation Human mesenchymal stromal cells osteogenic