Defective mitochondrial replacement in embryos ‘on the horizon’
MedWire News: Embryos for IVF carrying mitochondrial gene defects may eventually be able to have the defects corrected replaced after researchers replaced the mitochrondrial genome in monkey embryos, resulting in healthy births.
Shoukhrat Mitaliprov, from Oregon Health and Science University in the USA, and colleagues obtained mature metaphase II oocytes from female rhesus macaque monkeys using controlled ovarian stimulations.
Metaphase II spindle-chromosomes were then aspirated and isolated and inserted into the oocyte zona pellucida of an enucleated, mitochondrial-replete egg using laser-assisted zona drilling. The reconstructed oocytes were fertilized via intracytoplasmic sperm injection and the resulting embryos transferred.
Of 15 embryos implanted into nine female monkeys, three females became pregnant, one with twins and two with singletons, resulting in pregnancy and implantation rates of 33 percent and 27 percent, respectively.
The first pregnant monkey delivered two healthy twins by cesarean section, the second monkey gave birth to a healthy infant, and the third was still pregnant at the time of study completion. Analysis confirmed that the nuclear DNA in the three infants originated from the spindle donors, while the mitochondrial DNA came from the cytoplast donors.
Dr Mitalipov commented: "It is estimated that every 30 minutes a child is born with this devastating disease and I believe we could prevent that."
He added: "Moving to human trials could be very quick, maybe within 2 to 3 years.”
MedWire (www.medwire-news.md) is an independent clinical news service provided by Current Medicine Group, a part of Springer Science+Business Media. © Current Medicine Group Ltd; 2009
By Liam Davenport