A Perfusion Culture System for Assessing Bone Marrow Stromal Cell Differentiation on PLGA Scaffolds for Bone Repair.

Caroline Moser,Katie Bardsley,Alicia J El Haj,Jennifer J Bara,Mauro Alini,Martin J Stoddart

doi:10.3389/fbioe.2018.00161

Abstract

Biomaterials development for bone repair is currently hindered by the lack of physiologically relevant in vitro testing systems. Here we describe the novel use of a bi-directional perfusion bioreactor to support the long term culture of human bone marrow stromal cells (BMSCs) differentiated on polylactic co-glycolic acid (PLGA). Primary human BMSCs were seeded onto porous PLGA scaffolds and cultured in static vs. perfusion culture conditions for 21 days in osteogenic vs. control media. PLGA scaffolds were osteoconductive, supporting a mature osteogenic phenotype as shown by the upregulation of Runx2 and the early osteocyte marker E11. Perfusion culture enhanced the expression of osteogenic genes Osteocalcin and Osteopontin. Extracellular matrix deposition and mineralisation were spatially regulated within PLGA scaffolds in a donor dependant manner. This, together with the observed upregulation of Collagen type X suggested an environment permissive for the study of differentiation pathways associated with both intramembranous and endochondral ossification routes of bone healing. This culture system offers a platform to assess BMSC behavior on candidate biomaterials under physiologically relevant conditions. Use of this system may improve our understanding of the environmental cues orchestrating BMSC differentiation and enable fine tuning of biomaterial design as we develop tissue-engineered strategies for bone regeneration.

Highlights

Large bone defects and non-union fracture pose a significant socioeconomic burden, with bone being the second most transplanted tissue after blood products (Campana et al, 2014)
bone marrow stromal cells (BMSCs) were maintained in culture for 21 days on polylactic co-glycolic acid (PLGA) scaffolds in the perfusion bioreactor
Hematoxylin and Eosin (H&E) staining confirmed that independent of culture conditions, BMSCs were evenly distributed and viable for 21 days when cultured on PLGA

Summary

Introduction

Large bone defects and non-union fracture pose a significant socioeconomic burden, with bone being the second most transplanted tissue after blood products (Campana et al, 2014). There is increasing demand for bone grafts globally due to our aging population (Cheung, 2005) and higher incidence of fractures (Burge et al, 2007; Amin et al, 2014). Current gold standards for treatment are autologous or allogeneic bone grafts. Autologous bone grafts taken from the iliac crest are osteoinductive and osteoconductive (Khan et al, 2005). The size of the graft is limited (Megas, 2005) and donor site morbidity may be observed (Younger and Chapman, 1989).

Objectives

Methods

Results

Conclusion