A rapidly evolving revolution in stem cell biology and medicine

The developments arising from human IVF are remarkable. Embryos were studied for developmental patterns that have consequences for viability and fertility. Growing human blastocysts in vitro allowed further exploration of the differentiation of primitive embryonic cells, leading to the discovery of human embryonic stem cells (ESC). The availability of perhaps unlimited numbers of human ESC could inform the study of differentiation and also provide cells for therapies in human regenerative medicine. The developments in cell biology have been impressive, including the discovery of induced pluripotent stem cells - adult cells transduced by specific transcription factors to behave like human ESC. Key regulators of development such as activators or inhibitors of lineage progression have also been explored, particularly the fibroblast growth factor, Wnt and transforming growth factor β signalling pathways and miRNA. Such regulators can be utilized in algorithms to predict how cells differentiate in vitro. Using multistep differentiation protocols, many different cell types can be formed and matured into functionally effective cells, some of which are already in translational research for clinical applications. Possible future developments include destruction of cancer stem cells, reversal of type I diabetes, restoration of vision, repair of motor function, cure for HIV/AIDS and heart muscle regeneration.