Ever since Dolly, the first cloned sheep, made the global headlines, scientists, clinicians, businesspersons, and no small army of science fiction writers have been imagining the technology’s potential. However, the technical and ethical complexities of the task abound.
Now it appears that one very critical application of cloning technology may be realized by thinking small, as in the in vitro production of human platelets, according to Naoya Takayama, MD, PhD, of the Center for iPS Cell Research and Application at Kyoto University in Japan.
Dr Takayama and colleagues are pioneering a technique that avoids at least the ethical issues related to the use of embryonic stem cells by using pluripotent adult stem cells, which can come from any living person. “This work is preliminary, but the promise it holds is wonderful,” commented Peter D. Emanuel, MD, of the University of Arkansas for Medical Sciences, Little Rock, and Liaison, Chair, Committee on Communications for ASH 2011.
The technique described by Dr Takayama employed human-induced pluripotent stem cells (hiPSCs), specifically, an immortalized megakaryocyte progenitor cell line derived from hiPSCs, which is the bone marrow cell type responsible for producing thrombocytes (platelets). The megakaryocytes were induced to make platelets through temporal manipulation of the activation of the regulator gene, c-MYC, and associated downstream factors, INK4A and ARF. The resultant cell line subsequently showed proplatelet formation leading to the release of functional CD41a+/CD42b+ platelets.
The compatibility of the cloned cells was validated by the transfusion of platelets into immunodeficient mice. The platelets were accepted, and they exhibited normal circulation 24 hours after their transfusion.
Dr Takayama concluded, “Through gene manipulation one could potentially provide a stable supply of platelets at a predefined quality and quantity for transfusion therapy.”
“Platelet supplies for transfusions are always in short supply,” said Dr Emanuel. “The shelf life is short, and donors are less willing to donate because it takes more time than whole blood. So, if we could mass-produce them in the laboratory, it would be a major step forward.”
Dr Emanuel further pointed out that not only would patients benefit, but a ready-made platelet supply could dramatically reduce the associated costs.