Reprogramming of somatic cells: possible methods to derive safe, clinical-grade human induced pluripotent stem cells.

Derivation of pluripotent stem cells from adult somatic tissues by reprogramming technology has opened new therapeutic possibilities. Current most efficient procedures for derivation of induced pluripotent stem (iPS) cells are based on the viral vectors, which represent the danger of insertional mutagenesis during incorporation of introduced genes into the host genome. To circumvent this problem, the new, safe, non-integrative and non-viral strategies of reprogramming have been developed. In this review we discuss novel DNA-free and viral-free methods of reprogramming to iPS cells including protein transduction, mRNA and microRNA delivery.