Clonal analysis of nestin^- vimentin⁺ multipotent fibroblasts isolated from human dermis

Although several studies have shown that dermal fibroblasts possess adipogenic, osteogenic or chondrogenic differentiation potential, no study has characterized this cell population in detail, and there is as yet no evidence that a single dermal fibroblast can differentiate into all these types of cells. In this study, dermal fibroblasts were isolated from human foreskin using a regular dermal fibroblast culture system. These cells could be expended in adherent culture for over 40 cell doublings. In addition, dermal fibroblasts exhibited adipogenic, osteogenic and chondrogenic phenotypes when they were cultured in the presence of certain inducers. Importantly, clonal analysis showed that 6.4% (3/47) of the single-cell-derived clones were tripotent, 19.1% (9/47) of the clones were bipotent, and 10.6% (5/47) of the clones were unipotent. Furthermore, one of the three tested tripotent clones exhibited neurogenic and hepatogenic differentiation potential. Phenotypic analyses showed that the tripotent fibroblasts were nestin^- vimentin⁺, which is different from the dermis-derived stem cells reported by others. These results indicate that dermal fibroblasts are a heterogeneous population containing progenitors with various levels of differentiation potential, and the nestin^- vimentin⁺ fibroblasts may represent a novel type of multipotent adult stem cells in human dermis.