title: Microcarrier culture for efficient expansion and osteogenic differentiation of human fetal mesenchymal stem cells.
abstract: Stirred microcarrier (MC) culture has been suggested as the method of choice for supplying large volumes of mesenchymal stem cells (MSCs) for bone tissue engineering. In this study, we show that in addition to the improvement in cell expansion capacity, MSCs propagated and harvested from MC culture also demonstrate higher osteogenic potency when differentiated in vivo or in vitro in three-dimensional (3D) scaffold cultures as compared with traditional monolayer (MNL) cultures. Cytodex 3 microcarrier-expanded human fetal MSC (hfMSC) cultures (MC-hfMSCs) achieved 12- to 16-fold expansion efficiency (6×10(5)-8×10(5) cells/mL) compared to 4- to 6-fold (1.2×10(5)-1.8×10(5) cells/mL) achieved by traditional MNL-expanded hfMSC culture (MNL-hfMSCs; p<0.05). Both MC-hfMSCs and MNL-hfMSCs maintained similar colony-forming capacity, doubling times, and immunophenotype postexpansion. However, when differentiated under in vitro two-dimensional (2D) osteogenic conditions, MC-hfMSCs exhibited a 45-fold reduction in alkaline phosphatase level and a 37.5% decrease in calcium deposition compared with MNL-hfMSCs (p<0.05). Surprisingly, when MC-hfMSCs and MNL-hfMSCs were seeded on 3D macroporous scaffold culture or subcutaneously implanted into nonobese diabetic/severe combined immunodeficient mice, MC-hfMSCs deposited 63.5% (p<0.05) more calcium and formed 47.2% (p<0.05) more bone volume, respectively. These results suggest that the mode of hfMSC growth in the expansion phase affects the osteogenic potential of hfMSCs differently in various differentiation platforms. In conclusion, MC cultures are advantageous over MNL cultures in bone tissue engineering because MC-hfMSCs have improved cell expansion capacity and exhibit higher osteogenic potential than MNL-hfMSCs when seeded in vitro into 3D scaffolds or implanted in vivo.
authors.affiliation: Bioprocessing Technology Institute , Agency for Science, Technology, and Research (ASTAR), Singapore .
authors.forename: Tony Kwang-Poh
authors.initials: TK
authors.lastname: Goh
authors.forename: Zhi-Yong
authors.initials: ZY
authors.lastname: Zhang
authors.forename: Allen Kuan-Liang
authors.initials: AK
authors.lastname: Chen
authors.forename: Shaul
authors.initials: S
authors.lastname: Reuveny
authors.forename: Mahesh
authors.initials: M
authors.lastname: Choolani
authors.forename: Jerry Kok Yen
authors.initials: JK
authors.lastname: Chan
authors.forename: Steve Kah-Weng
authors.initials: SK
authors.lastname: Oh
keywords: bioreactor; bone tissue engineering; fetal human mesenchymal stem cells; in vivo ectopic bone formation; microcarrier