Mitochondrial donation recognized as safe
"Children from three parents" were promised already in 2017
The "three parents" procedure – mitochondrial transplantation during in vitro fertilization – was successfully performed on healthy human embryos for the first time. Successful implementation of the operation makes it possible to use it in medicine as early as the end of 2017, according to the journal Nature (Hyslop et al., Towards clinical application of pronuclear transfer to prevent mitochondrial DNA disease).
The "three parents" method consists in transplanting mitochondrial DNA from a female donor into the mother's egg, as a result of which the child receives mitochondrial DNA from a third party. Scientists believe that this avoids the influence of mutations on the part of the mother, which can lead to diseases such as diabetes syndrome and deafness.
In 2010, Doug Turnbull from Newcastle University and his colleagues developed a new method related to the fact that the harmful mitochondria in the egg are far from the nucleus (with DNA). So, you can first fertilize an egg, and then extract the nucleus from it and transplant it into a donor cell with healthy mitochondria.
Initially, the new method was tested only on defective embryos rejected during IVF procedures. At the same time, Turnbull found out that part of the dangerous mitochondrial DNA still gets into the embryo – because of liquid droplets sticking to the cell nucleus during transplantation.
As part of a new study, scientists transplanted the nucleus 200 times using healthy donor eggs. Scientists have managed to improve the procedure and dramatically reduce the number of harmful mitochondria.
As a result, 79 percent of the resulting embryos turned out to have less than 2 percent of harmful mtDNA, while 42 percent did not detect it at all. The minimum indicator for healthy fetal development is considered to be 30 percent. In addition, the researchers raised the embryo survival rate from 40 to 90 percent by shifting the time of core extraction: previously, this procedure was carried out after 24 hours, now – after 8 hours.
The UK authorities have until the end of 2016 to assess the safety of this method and decide whether it can be applied to live patients.
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09.06.2016