In 2006, a team of researchers led by Dr. Shinya Yamanaka at Kyoto University, Japan, made a startling breakthrough by identifying conditions that would allow some specialized adult cells to be genetically “reprogrammed” to behave like pluripotent (capable of becoming many types of tissue) embryonic-like stem cells. This new type of stem cell is called an induced pluripotent stem cell, or iPSC. Dr. Shinya Yamanaka was awarded the Wolf Prize in Medicine for his discovery.
Cited as an important advance in stem cell research, it allows researchers to obtain pluripotent stem cells without the controversial use of embryos. Because iPSC’s are developed from a patient’s own somatic (skin, for example) cells, any tissues derived from iPSC’s would be a nearly identical match to the cell donor, thus avoiding rejection by the immune system. Researchers in recent years have challenged the assumption that there would be no immune response.
Depending on the methods used, reprogramming of adult cells to obtain iPSC’s may pose significant risk for human use. For example, viruses used to genetically alter the cells may trigger the expression of oncogenes (cancer-causing genes). In 2008, a technique to remove oncogenes after the induction of pluripotency was discovered, increasing the potential use of iPSC’s to treat human disease. In 2009, scientists demonstrated that iPSC’s could be generated without any genetic alteration of the adult cell with the repeated channeling of certain proteins into the cells. The acronym given those cells is piPSC, or protein-induced pluripotent stem cells.
The development of an abundant source of pluripotent stem cells significantly advances ongoing research in the programming of cells to repair or replace damaged tissues in the human body. Although additional research is needed, iPSCs are already useful tools for drug development and disease modeling.