Figure 6: Hair follicle dermal cells maintain human iPSCs in an undifferentiated state. Human iPSCs were grown on either MEF, human SF, DP, or DS cells. On MEFs, iPSCs maintained normal ESC-like morphology (a), high alkaline phosphatase (b), Tra-1-60 (c), and Tra-1-81 (d) expression. In comparison, when grown on fibroblast feeders, the iPSC colonies became less compact (e), and with increasing passage number lost expression of pluripotency markers and alkaline phosphatase (f–h). When grown on hair follicle dermal cells, DP (i–l), but particularly DS (m–p), the iPSCs maintained normal ESC morphology and high levels of expression of ESC pluripotency markers for several passages in culture. Scale bars = 100 μm.