It’s one of the hazards of reading science journalism, most of the news is positive – this advance, that breakthrough, etc. It’s easy to get the impression that a particular science – in this case research that creates pluripotent stem cells from adult (non-embryonic) cells – is rushing headlong to great things. It might be, but there are ‘speedbumps’ – the quaint automotive phrase for hitting obstructions that slow down progress. For induced stem cells, that speedbump is not matching the full capabilities of embryonic stem cells. This is the conclusion of a paper by the University of Wisconsin-Madison School of Medicine and Public Health that studied the use of induced pluripotent stem cells as neuron cells.
The new study, led by Su-Chun Zhang, compared five embryonic stem cell lines with twelve induced stem cell lines. They found that the induced pluripotent stem cells (iPS) converted to neuron cells do not match all the differentiations made by embryonic stem cells. The study also showed that iPS cells created without using genes, which in theory should have resulted in ‘cleaner’ differentiation, did no better than gene induced cells. As Dr. Zhang explains…
It was predicted that the absence of exotic genetic factors would result in cells essentially identical to embryonic stem cells. “It is totally surprising that doesn’t happen at all,” says Zhang. “It tells us the techniques for generating induced pluripotent stem cells are still not optimal. There is room for improvement.”
Despite their unpredictability, Zhang notes that induced stem cells can still be used to make pure populations of specific types of cells, making them useful for some applications such as testing potential new drugs for efficacy and toxicity. He also noted that the limitations identified by his group are technical issues likely to be resolved relatively quickly.
“It appears to be a technical issue,” he says. “Technical things can usually be overcome.”
The key, he explains, is determining what things are at play that make the induced cells different.
It is unclear whether not knowing ‘what things are at play’ – possibly some fundamental information is missing – constitutes a technical issue.