The Prospects and Challenges of Cell-Based Therapies

With the emergence of induced pluripotent stem cell (iPSC) technology, the somatic cells can be reprogrammed to pluripotent state, and thus the new paradigm to generate patient-specific pluripotent stem cells for disease pathogenesis and cell therapy. These iPSCs produced from a variety of somatic cell sources are found to be very similar if not identical to embryonic stem cells. Currently the most efficient way to produce such cells is by viral transduction with a combination of transcriptional factors and as such that renders these cells unfit for therapeutic purposes. However, recently there is further development in methods for generating iPSCs with minimal or no genetic modifications via excisable lentiviral and transposon vectors or through repeated application of transient plasmid, episomal, and adenovirus vectors and very recently the use of small molecules, synthetic mRNA and microRNAs. However, as it is becoming evident now that the cell type of origin influences the molecular and functional properties of derived iPSC. The indications that reprogramming may erase the cell memory also raises the question if the disease phenotype may not be correctly represented or also erased in iPSC unless coaxed by further perturbation in vitro culture conditions. Similarly other tissue-derived stem cells and hESC-derived lineages offer an unprecedented opportunity in biomedical research, cell therapy and regenerative medicine. However, to harness the full potential of these technologies, a number of issues need to be resolved pertaining to their safety, stability, culture variability, and better ways to direct a specific reprogramming process including lineage specifications. Both hESC and iPSC fields offer phenomenal opportunities to study the basic molecular mechanistic of human development, their use in disease modelling, regenerative medicine and drug discovery. A steady progress in transitional and translational research particularly in various disease animal models and very recently some human trials with these cells are very encouraging. This chapter briefly summarises (not review) the recent developments in stem cell therapy, pitfalls and development.

Keywords: Cell therapy, stem cells, induced pluripotency, transplantation, graft rejection, regulation.