Promises and Challenges of the First Clinical-Grade Induced Pluripotent Stem Cell Bank

Abstract

It has only been approximately 6 years since Shinya Yamanaka, a Japanese scientist from Kyoto University, found a way of reverting differentiated cells from an adult into an embryoniclike pluripotent state [1]. These cells, termed induced pluripotent stem (iPS) cells are as powerful as human embryonic stem (hES) cells; they can be expanded infinitely, and upon differentiation provide an unlimited number of cells for autografts or close HLA-matched recipients, completely avoiding or significantly reducing the host immune response and need for immunosuppression. Importantly, they can be obtained by simple, minimally invasive procedures, such as phlebotomy or hair plucking, which are free from the ethical issues that plague the hES cell field. For his revolutionary work, Yamanaka was awarded the Nobel Prize in 2012. Following this major breakthrough in regenerative medicine everybody, including government funding agencies, jumped on the iPS cell bandwagon. In July 2011, the Innovative Medicines Initiative, Europe’s largest public–private initiative, launched a call for the generation of banks of iPS cells for drug discovery and safety assessment. The California Institute for Regenerative Medicine is intending to build a bank containing several thousand iPS cell lines for distribution to researchers, while the UK has its own plans too. However, iPS cell-based therapy was not considered in any of these cases. Most of the lines will be derived from people with various diseases in order to study disease pathophysiology. Yet, in spite of insufficient knowledge about the nature of these cells, unresolved technical issues, labor-intensive methodology and prohibitive costs, Yamanaka, supported by the Japanese government, recently revealed plans to build a bank of iPS cells for therapeutic use [2]. This bank of 75 iPS cell lines with carefully selected HLA haplotypes would match nearly 80% of