KYOTO – A Japanese research team said Friday it has developed a method for mass producing human cells that can develop into other tissue.
The team, including Norio Nakatsuji of Kyoto University’s Institute for Integrated Cell-Material Sciences, announced the outcome of joint research conducted with Nissan Chemical Industries Ltd. on the online version of the U.S. journal Stem Cell Reports.
Researchers usually use culture plates and fluids to produce pluripotent stem cells, such as induced pluripotent stem, or iPS, cells and embryonic stem cells.
In fluids, the cell survival rate tends to fall because of the damage they incur when fluids are stirred, and because the spontaneous fusion of cell aggregates often results in cell deaths. Larger cell aggregates are more prone to death.
The team found that it can fragment cell aggregates into smaller ones by passing them through mesh filters. By performing the process every five days, the team managed to create small, even cell aggregates, curbing cell deaths.
The team also made it unnecessary to stir culture fluids by introducing nontoxic polymers that keep cell aggregates suspended in culture fluids and prevent them from sinking to the bottom.
By combining the techniques, the team reduced cell loss caused by fusion and damage. It succeeded in producing a large amount of pluripotent stem cells in a single plastic bag filled with culture liquid.
“We aim to achieve the production of 10 billion cells, enough to treat a patient, in 10 liters of culture liquid over the coming three years,” Nakatsuji said.
Separately, another team of researchers including Shinya Yamanaka of Kyoto University’s Center for iPS Cell Research and Application has announced the discovery of a protein called FOXH1 that promotes the reacquisition of pluripotency by human cells, according to an article published on the online version of the British journal Nature Communications.
Team member Kazutoshi Takahashi said the use of the protein has boosted iPS cell production efficiency to around 20 percent from 1 percent under the original method using the four genes discovered by Yamanaka.