Abstract
BACKGROUND AND OBJECTIVES: Mesenchymal stem cells (MSCs) have been obtained from various human tissues by harvesting plastic adherent fibroblast-like cell population. For potential use in regeneration medicine, early passage MSC population is preferred to avoid cell senescence. The early passage adherent cell population contains MSCs as well as fibroblasts, however, the significance of the contained fibroblasts has not been well investigated. Thus, we investigated the stem cell characteristics of the early passage MSC population with and without fibroblasts depletion. METHODS AND RESULTS: We obtained adherent cell populations from full term placenta at passage 2∼3 and divided them into two subpopulations: fibroblasts depleted (popFD) and non-depleted population (popFND) using magnetic cell sorting method. The two subpopulations were compared in terms of cell morphology, potential for long term culture, colony forming ability, and tri-lineage differentiation for adipogenic, chondrogenic, and osteogenic differentiation. The percentage of fibroblasts contained in the early passage MSC population was 5.3% (2.9∼8.4). Both the popFD and popFND was spindle shaped from early passages and maintained long term culture up to 20∼22 passages. CFU-F assay showed no difference between the subpopulations. Overall, tri-lineage differentiation showed a tendency of better differentiation potential of popFND than popFD. CONCLUSIONS: We confirmed that fibroblasts are contained in early population of placenta-derived MSCs obtained by current method. This study revealed that the contained fibroblasts in early passage MSC population do not adversely affect the properties of MSCs in terms of cell morphology, potential for long term culture, colony forming ability, and tri-lineage differentiation.