Australian researchers have developed a test to identify unsafe stem cells. Stem cells may one day be used to help regrow damaged body parts, and the new test potentially reduces the risk of unwanted tumours forming.
Stem cells are used for the study of diseases such as diabetes, macular degeneration, heart problems and brain disorders. Japanese researchers are planning a trial using a certain type of stem cells called induced pluripotent stem cells to regrow damaged retina cells in humans.
The new test, developed by the CSIRO and published in the journal Stem Cells, helps to identify stem cells that could form tumours when they are injected into tissue, a problem that has been identified in tests on mice.
The study was conducted over five years and, using the new test, assessed different types of methods used to make iPS cells . The test used laser technology to compare different types of iPS cells with human embryonic stem cells. The unsafe cell lines could be recognised because they formed clusters of cells that were different to safe ones.
The results showed that iPS cells created using the standard technique (the “viral method”, which works by permanently changing the cell’s DNA) were much more likely to cause tumours.
The test also revealed that other methods that don’t change the DNA of the original cell were safer.
“It’s the method that’s used to make human iPS cells that’s important. The method used can introduce a degree of instability that leads to some of the cell lines not being safe - in that they can form tumours known as teratomas,” said lead researcher Dr Laslett.
“It’s interesting that the method that in our test appears to be safer is the method that the first team in the world to talk about doing human clinical trials using iPS cells is planning to use.”
Dr Martin Pera, Chair of Stem Cell Science at The University of Melbourne, who was not involved in the study, said that it “provides a new tool for assessing the safety of induced pluripotent stem cell lines.”
“This reversion test is a simple and powerful technique for assessing how safe stem cell lines are for use in patients.”
Dr Merlin Crossley, Professor of Molecular Biology at University of New South Wales, also not involved in the study, said the new findings were important because the test identifies which cells could be potentially harmful.
“People will be able to find it to work out how much to use, how long, and to test whether the cells are differentiating properly and whether they’re at what seems to be a safe state.”