A new, embryo free technology may be in the making for stem cell research. Scientists fused adult skin cells with laboratory-grown embryonic stem cell (ES cell), and then saw the hybrid cells revert back to an embryonic state. If perfected, this technology could provide a way to obtain ES cells for research and therapeutic applications without the need to use human eggs and embryos.
The work, to be published in the journal Science this week, was performed by researchers at Harvard University Medical School in Massachusetts. They found that when they fused adult skin cells with ES cells, the resulting hybrid cells acted like ES cells. When injected into mice, they formed tumours called teratomas. They contained the chemical markers of ES cells, and when cultured, the cells differentiated into the three basic types of cell.
According to the researchers, this is a step in the right direction to understanding how to reprogram cells - to make a cell that already has a single role in the body go back to a state where it could potentially develop into any type of cell. 'We've taken back a cell that had only one choice, a specialised function, and we've given it back the power to make many different choices, like an embryonic stem cell', says Chad Cowan, an author of the report. In addition, it could provide a way to generate stem cells for research and therapeutic applications without the need to harvest them from a human embryo that would be destroyed in the process, making it a more ethically-neutral possibility.
However, the researchers also emphasise that the technology is at an early stage in development. Kevin Eggan, another of the paper's authors, stated 'our technology is not ready for prime-time yet. Our results do not offer an alternative now'. They do not wish their findings to decrease support for current stem cell research that involves extracting ES cells from human embryos.
At the moment, the technology is inefficient and characterised by a 'substantial technical barrier'. About 50 million skin cells and another 50 million ES cells yield only 10 or 20 fused hybrid cells. As well, these hybrid cells contain two sets of DNA: one from the adult skin cell and one from the ES cell. Therefore, it would not be a perfect genetic match to the adult skin cell donor. In order for this technology to be used to treat diseases and other conditions, scientists would have to find a way to remove the ES cell DNA without also taking away the hybrid cell's ability to reprogram itself back to an embryonic state, ready to differentiate into a wide range of cell types. Some scientists believe this is feasible, possibly by extracting the ES cell DNA before fusion is complete, but nothing has been shown yet. According to Dr Petra Hajkova at the Gurdon Institute at Cambridge University, 'work from mice shows that if you remove the stem cell's nucleus before fusion, reprogramming doesn't occur'.
Professor Miodrag Stojkovic, Deputy Director of the Centre for Stem Cell Biology and Developmental Genetics at the University of Newcastle, UK, said 'this is interesting research which will help us understand how the nuclei of adult cells can reprogram. However, these cells would not be useful for stem cell treatments, because they are abnormal. These cells have 92 chromosomes instead of the normal 46. So nuclear transfer still remains the only procedure to derive patient-specific stem cells with a normal set of chromosomes'.
Sources and References
-
Harvard stem cell workaround
-
Skin cells converted to stem cells
-
Harvard scientists advance cell work
Leave a Reply
You must be logged in to post a comment.