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The development of new therapies to treat different diseases always goes through stages of promise and problems.
There are generally high expectations as the first bits of data appear. These studies are usually followed by new studies that have built upon the initial ones, and start to reveal the limitations of the therapy.
Umbilical cord blood for the treatment of hematopoietic diseases has had a slow but steady climb towards becoming a standard of care. It has been over 20 years since the first bone marrow transplant has been done using umbilical cord blood as the donor cell source. Since then there has been an exponential growth in umbilical cord blood use worldwide. This steady climb is more an exception than the rule.
In 2006, there was the announcement that a Japanese group of brilliant scientists managed to turn mature skin cells back into embryonic cells (Takahashi, K. & Yamanaka, S. Cell 126, 663–676 (2006)). These cells are referred to as induced pluripotent stem cells (iPS cells). This news would have a profound effect on the stem cell field and heralded a new era for cell-based therapies. Many scientists working with other stem cells such as umbilical cord blood realized that this novel source of cells from skin could replace all other stem cell sources. We visualized skin cell banks instead of umbilical cord blood banks. But as for most new discoveries in science as more laboratories enter the arena and push the limits of the technology some applications survive and others fall by the wayside. iPS cells have had great success and are now facing challenges.
Recent studies have demonstrated that iPS cells can develop genetic abnormalities during their production (Hussein, S. M. et al. Nature 471, 58–62 (2011)). This would lead to unsafe cells that would not be suitable for transplantation. Another study indicated that iPS cells could be rejected even if transplanted into the person they were derived from (Nature (2011) doi:10.1038/nature10135). This is surprising as it is expected that your own cells would not be rejected. Turns out that again, during the production of iPS cells, they undergo changes that make them immunologically different from the original cell. Already laboratories are asking questions and trying to find out if this is a phenomenon specific to this one experiment or is this a general trend for iPS cells?
Science goes in cycles and as more laboratories start to investigate both the mutation and the rejection results more thoroughly it is likely the role for iPS cells in the treatment of disease will be defined. For example, a role for iPS cells derived from patients with specific disease will allow scientists to study the development of the disease and to obtain a better understanding of the disease. This will also allow scientists to study the disease in individual patients and tailor treatment to each patient.
Dr. Ian Rogers
Dr. Rogers is an Associate Scientist and Assistant Professor at the Samuel Lunenfeld Research Institute of Mount Sinai Hospital, in Toronto, Canada. He also serves on the scientific advisory board to the Parent’s Guide to Cord Blood Foundation and is a scientific advisor to Insception Lifebank Cord Blood Program.