Development of a microcarrier-based cellular expansion technique for the clinical application of human fetal mesenchymal stem cells

Abstract

In order to derive the maximum potential benefit of stem cell therapy, two of the key challenges are the generation of clinically relevant numbers of cells and the reduction in reliance on serum in cell culture media. This report aims to develop a microcarrier based and serum-free cellular expansion technique for the clinical application of human fetal mesenchymal cells (hfMSC). In this study, a harvesting process involving either Trypsin or Collagenase was investigated for hfMSC on Cytodex 3 microcarriers. A subsequent immunophenotype assay, proliferative potential assay and osteogenic differentiation were performed on harvested cells in order to observe for changes in their characteristics. Cell harvesting was found to be the most effective for 30 and 60 minutes of Trypsin and Collagenase treatment respectively, achieving high cell yield and vitalities near 100%. Although microcarrier expanded cells and monolayer cells have comparable immunophenotypes and proliferative potential, the osteogenic potential of the former was lower than the latter. This study also included a comparison between serum-based D-10 medium and serum-free MesenCult-XF medium. MesenCult-XF medium supported cell growth extensively both in monolayers and on microcarriers, reaching a density of 4.08 x 105 cells/ml on day 8 of microcarrier culture. It also contained lower levels of metabolites during monolayer culture even without medium exchanges. However, it may have caused hfMSC on microcarriers to lose their immunophenotype and also a reduction in osteogenic potential of both microcarrier and monolayer expanded cells.