These are very interesting studies. The purpose of these studies might be making pluripotent cells from adult stem cells by fusing them with embryonic stem cells. Unfortunately, tetraploid cells made tumors in Terada's study, which we expected. Smith's study is showing chimera formation of the fused cells, but the authors have to check the function of the tissue made by the fused cells before they conclude the functionality of the cells. They also failed to show multipotency in vitro. If the cells have extra genes, we would expect their physiology to be disturbed.

When I inserted an extra AβPP gene into neural stem cells, they started to differentiate into glial cells rather than neurons. In other words, they might be making Down's syndrome models. Thus these lines of study may not help generate new material for neuroreplacement therapy for AD.

View all comments by Kiminobu Sugaya