http://www.the-scientist.com/?articles.view/articleNo/36664/title/A-Wild-Stem-Cell-Chase/ A controversy in the stem-cell research community this week spilled over into mainstream media. A number of leading researchers gave interviews or wrote articles about the disputed potential of Very Small Embryonic Stem Cells (VSELs).
VSELs appeared in the 2000s as a pluripotent alternative to embryonic stem cells. Polish scientist Mariusz Ratajczak from the University of Louisville claims the cells, found in bone marrow, can develop into a range of tissues and human body structures. Ratajczak is the leader of a US$14 million research network which this year began the first human trial of a VSEL preparation, aiming to treat 60 people who have severe angina.
However, four successive studies have failed to find the cells with the properties that Ratajczak described. The latest study , published by Stanford University academics in Stem Cell Reports, is said to signal the death knell for the theory. In this study researchers replicated Ratajczak's method, but found no indication of pluripotency. The lead author, Irving Weismann, believes the alleged VSELs are simply cell debris and fragments from dying cells.
Wiessman gave an interview to Nature Magazine dismissing VSELs. His comments were echoed in a similar interview with German academic Rüdiger Alt, who published a study with the same findings last year.
Ratajczak hit back in his own interview with Nature , claiming Weissman did not use the right techniques. 'Weissman has never visited my lab to witness exactly how we carry out the method," he says. Russell Taichman of University of Michigan Ann Arbor defended Ratajczak: "I don't see the controversy - we have seen bone grow [from VSELs in mice]".
The controversy was even reported on NBC, with an op-ed by bioethicist Arthur Caplan. Caplan hit out at the Vatican, which made a US$1 million donation to Ratajczak's research in 2011: "when the power of religion is used to cheer for a particular research strategy not because of evidence but because of morality that creates a huge potential for trouble."