(Reuters) - Scientists have for the first time created blood platelet cells by reprogramming stem cells derived from adult cells, offering the potential for a renewable supply of the fragile blood component.

Researchers at the Center for iPS Cell Research and Application at Kyoto University in Japan presented data at a meeting of the American Society of Hematology showing they were able to create the cells in the laboratory and confirm they had the same life span as normal human platelets when infused in mice.

"The next step will be to conduct a trial to determine whether our platelets can function in the human body," said Dr. Koji Eto, professor at the Kyoto center and senior author of the study.

Induced pluripotent stem cells, or iPS cells, are produced by manipulating ordinary human skin or blood cells back to a state in which they are able to differentiate into a number of different cell types.

When they were first discovered in 2006, iPS cells looked like a perfect solution to the ethical debate over the use of embryonic stem cells, but the process of producing non-mutated cells has proved challenging.

The limitation in using stem cells to produce platelets has been the ability to find a method that creates a large number of high-quality, functional platelets.

The Japanese researchers set out to create an immortalized cell line with a large number of high-quality megakaryocytes -- precursor cells that develop into platelets -- from stem cells that can be grown indefinitely and differentiate into a variety of cell types in the body.

They were able to produce a cell line that turned off certain genes to generate functional platelets. They then tested the cultured platelets by infusing them into immunodeficient mouse models and confirmed that they had the same life span as human platelets infused in mice.

"This has the potential of marching us forward to a day when we might to able to eliminate blood platelet shortages," said Dr. Charles Abrams, ASH secretary and associate chief of hematology/oncology at the University of Pennsylvania in Philadelphia.

In normal clotting, platelets stick together and form a plug at the site of an injured blood vessel, allowing the injured site to heal.

Platelets used for transfusions are derived from donated blood but they have a short shelf life since they must be stored at room temperature and cannot be frozen.

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