New Research Raises The Prospect Of Wiping Out Diseases Passed On From Mothers To Their Children

by Aruna on Aug 29 2009 8:45 AM

Researchers have developed a new technique that could banish a host of crippling inherited diseases forever.

The landmark research at Oregon Health and Science University's Oregon National Primate Research Center (ONPRC) raises the prospect of wiping out diseases passed on from mothers to their children through mutated DNA in cell mitochondria.

"We believe this discovery in nonhuman primates can rapidly be translated into human therapies aimed at preventing inherited disorders passed from mothers to their children through the mitochondrial DNA, such as certain forms of cancer, diabetes, infertility, myopathies and neurodegenerative diseases," said Shoukhrat Mitalipov, from Oregon Health and Science University (OHSU).

Mitochondria are structures that are found in all cells that provide energy for cell growth and metabolism, which is why they are often called the cell's "power plant."

The structures produce energy to power each individual cell. Mitochondria also carry their own genetic material.

When an egg cell is fertilized by a sperm cell during reproduction, the embryo almost exclusively inherits the maternal mitochondria present in the egg. This means that any disease-causing genetic mutations that a mother carries in her mitochondrial DNA can be passed on to her offspring.

OHSU researchers' method transfers the mother's chromosomes to a donated egg that has had its chromosomes removed, but which has healthy mitochondria, thereby preventing the disease from being passed on to one's offspring.

During the research, scientists collected groups of unfertilized eggs from two female rhesus macaque monkeys (monkeys A and B). They then removed the chromosomes, which contain the genes found in the cell nucleus, from the eggs of monkey B, and then transplanted the nuclear genes from the eggs of monkey A into the eggs of monkey B.

Then the eggs from monkey B, which now contained their own mitochondria but monkey A's nuclear genes, were fertilized. The fertilized eggs developed into embryos that were implanted in surrogate monkeys.

The initial implantation of two embryos resulted in the birth of healthy twin monkeys. These monkeys are the world's first animals derived by spindle transfer.

Follow-up testing showed that there was little to no trace of cross-animal mitochondrial transfer using this procedure. This shows that the researchers were successful in isolating nuclear genetic material from mitochondrial genetic material during the transfer process.

"In theory, this research has demonstrated that it is possible to use this therapy in mothers carrying mitochondrial DNA diseases so that we can prevent those diseases from being passed on to their offspring," Mitalipov said.

"We believe that with the proper governmental approvals, our work can rapidly be translated into clinical trials for humans, and, eventually, approved therapies," Mitalipov added.

The research has been published in the Aug. 26 advance online edition of the journal Nature.