De-differentiation protocols are described herein for generating progenitor cells from adult connective tissue, in particular adult human fibroblasts. The de-differentiation protocols described herein comprise culturing the differentiated cells with an amount of FGF2 to de-differentiate the cells. These de-differentiated cells may then be cultured and used for experimentation, amplification and clinical applications. The clinical applications include the use of the cells for tissue and cell based therapies.
