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.

BackgroundWe have previously obtained a clonal population of cells from human foreskin that is able to differentiate into mesodermal, ectodermal and endodermal progenies. It is of great interest to know whether these cells could be further differentiated into functional insulin-producing cells.ResultsSixty-one single-cell-derived dermal fibroblast clones were established from human foreskin by limiting dilution culture. Of these, two clones could be differentiated into neuron-, adipocyte- or hepatocyte-like cells under certain culture conditions. In addition, those two clones were able to differentiate into islet-like clusters under pancreatic induction. Insulin, glucagon and somatostatin were detectable at the mRNA and protein levels after induction. Moreover, the islet-like clusters could release insulin in response to glucose in vitro.ConclusionsThis is the first study to demonstrate that dermal fibroblasts can differentiate into insulin-producing cells without genetic manipulation. This may offer a safer cell source for future stem cell-based therapies.

A stable image mosaics algorithm based on PSO and SIFT is proposed in this paper. It adopts SIFT operator to extract corner point feature and finishes gray cross correlation matching, most false matches are eliminated by transcendental knowledge and constraint, then the transform matrix initial value between matches in two images is calculated, the optimal value of this matrix is acquired by PSO, finally, the image mosaics with no gap is accomplished. The experiment results prove the validity and practicability of the proposed method.