A new protocol for reprogramming induced pluripotent stem cells (iPSCs) into mature blood cells, using just a small amount of the patient’s own blood and a readily available cell type, is reported on in the current issue of STEM CELLS Translational Medicine. This novel method skips the generally accepted process of mixing iPSCs with either mouse or human stromal cells during the differentiation process and, in essence, ensures no outside and potentially harmful DNA is introduced into the reprogrammed cells.
As such, it could lead to a purer, safer therapeutic grade of stem cells for use in regenerative medicine.
The discovery of iPSCs holds great promise for regenerative medicine since it is possible to produce patient-specific iPSCs from the individual for potential autologous treatment — that is, treatment using the patient’s own cells. This avoids the possibility of rejection and numerous other harmful side effects.
CD34+ cells are a type of blood stem cell that has been linked to proliferation. However, collecting enough CD34+ cells from a patient to produce an adequate amount of blood usually requires a large volume of blood to be taken from the patient. But scientists found a way around this, as outlined in the new study conducted by researchers in the Department of Medicine and Institute for Human Genetic, University of California-San Francisco. They were led by Yuet Wai Kan, M.D., FRS, and Lin Ye, Ph.D.
“We used Sendai viral vectors to generate iPSCs efficiently from adult mobilized CD34+ and peripheral blood mononuclear cells (MNCs),” Dr. Kan explained. “Sendai virus is an RNA virus that carries no risk of altering the host genome, so is considered an efficient solution for generating safe iPSC.”
“Just 2 milliliters of blood yielded iPS cells from which hematopoietic stem and progenitor cells could be generated. These cells could contain up to 40 percent CD34+ cells, of which approximately 25 percent were the type of precursors that could be differentiated into mature blood cells. These interesting findings reveal a protocol for the generation iPSCs using a readily available cell type,” Dr. Ye added. “We also found that MNCs can be efficiently reprogrammed into iPSCs as readily as CD34+ cells. Furthermore, these MNCs derived iPSCs can be terminally differentiated into mature blood cells.”
“This method, which uses only a small blood sample, may represent an option for generating iPSCs that maintains their genomic integrity,” said Anthony Atala, MD, Editor of STEM CELLS Translational Medicine and director of the Wake Forest Institute for Regenerative Medicine. “The fact that these cells were differentiated into mature blood cells suggests their use in blood diseases.”
The full article, “Blood cell derived induced pluripotent stem cells free of reprogramming factors generated by Sendai viral vectors,” can be accessed at http://www.stemcellstm.com.