Macropore design of tissue engineering scaffolds regulates mesenchymal stem cell differentiation fate

• Published in: Biomaterials Vol. 272; p. 120769
• Main Authors: Swanson, W.Benton, Omi, Maiko, Zhang, Zhen, Nam, Hwa Kyung, Jung, Younghun, Wang, Gefei, Ma, Peter X., Hatch, Nan E., Mishina, Yuji
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Ltd 01-05-2021
• Subjects: Animals; Cell Differentiation; Cells, Cultured; Craniosynostosis; Humans; Macropore; Mesenchymal Stem Cells; Mice; Osteogenesis; Scaffold; Stem cell niche; Tissue Engineering; Tissue Scaffolds; Vascularization; Stem cell niche; Scaffold; Craniosynostosis; Osteogenesis; Macropore; Vascularization
• ISSN: 0142-9612; 1878-5905
• DOI: 10.1016/j.biomaterials.2021.120769

Craniosynostosis is a debilitating birth defect characterized by the premature fusion of cranial bones resulting from premature loss of stem cells located in suture tissue between growing bones. Mesenchymal stromal cells in long bone and the cranial suture are known to be multipotent cell sources in the appendicular skeleton and cranium, respectively. We are developing biomaterial constructs to maintain stemness of the cranial suture cell population towards an ultimate goal of diminishing craniosynostosis patient morbidity. Recent evidence suggests that physical features of synthetic tissue engineering scaffolds modulate cell and tissue fate. In this study, macroporous tissue engineering scaffolds with well-controlled spherical pores were fabricated by a sugar porogen template method. Cell-scaffold constructs were implanted subcutaneously in mice for up to eight weeks then assayed for mineralization, vascularization, extracellular matrix composition, and gene expression. Pore size differentially regulates cell fate, where sufficiently large pores provide an osteogenic niche adequate for bone formation, while sufficiently small pores (<125 μm in diameter) maintain stemness and prevent differentiation. Cell-scaffold constructs cultured in vitro followed the same pore size-controlled differentiation fate. We therefore attribute the differential cell and tissue fate to scaffold pore geometry. Scaffold pore size regulates mesenchymal cell fate, providing a novel design motif to control tissue regenerative processes and develop mesenchymal stem cell niches in vivo and in vitro through biophysical features.
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•Well-controlled macropore design regulates stem cell differentiation fate in 3-D scaffolds.•Pores >250 μm diameter support osteogenic differentiation, vascularization and mature ECM.•Pores <125 μm diameter support maintenance of stemness, immature ECM and reduced vascularization.•Macroporous scaffolds are able to modulate cell fate in vitro and direct cell trajectory in vivo.