A Three-Dimensional Scaffold-Based System for Modeling the Bone Marrow Tissue

Hematopoietic stem and progenitor cells (HPC) niche, consisting of HPC and their surrounding stromal components, is the fundamental unit for bone marrow (BM) tissue engineering. Previously, mouse BM-derived cell complexes with HPC niche unit properties called "niche-like units" were isolated and characterized. This study was aimed to evaluate the possibility of bioengineering marrow tissue in heterotypic sites using niche-like units in combination with three-dimensional scaffolds. BM niche-like units were isolated from GFP-transgenic C57BL/6 mice and seeded on electrospun poly (L-lactide) nanofiber scaffolds, which were then roll-folded and aseptically implanted into the peritoneal cavity of irradiated wild-type mice. One month after implantation, donor-derived cells were detected in peripheral blood of the recipients and contributed to restoration of all blood lineages. The transplanted bioengineered tissue histologically resembled native BM structure and was connected to the mouse systemic circulation. Long-term self-renewal was confirmed by serial transplantation into tertiary recipients. In conclusion, this study establishes a novel system for BM tissue engineering, which can be used to improve the HPC transplantation outcomes especially in cases where HPC niche is damaged and also as an in vivo model to test the effects of different factors on hematopoiesis.