Therapeutic Option For Women With Mutant Mitochondrial DNA
December 20, 2012

New Technique Aims To Limit Inherited Disorders

Connie K. Ho for — Your Universe Online

Researchers from the Columbia University Medical Center (CUMC) and the New York Stem Cell Foundation (NYSCF) have been able to create a new technique that limits inherited disorders in children.

The ability of scientists to transfer the nucleus of a cell from one human egg cell to another was considered an important achievement, and results of the study were recently published in the online edition of Nature.

In particular, the researchers explained how mitochondria can help in the maintenance and growth of a cell. Disorders of mitochondria can be harmful and are found in about every one in 10,000 people. Mutant mitochondrial DNA is found in almost one in every 200 individuals. Kidney disease, neurological disorders, respiratory issues, weak muscles, along with difficulties in hearing and seeing, are a few of the symptoms associated with mitochondrial disease.

"Through this study, we have shown that it should be possible to prevent the inheritance of mitochondrial disorders," explained a co-author of the study Dieter Egli, who serves as the Senior Researcher in the NYSCF Laboratory, in a prepared statement. "We hope that this technique can be advanced quickly toward the clinic where studies in humans can show how the use of this process could help to prevent mitochondrial disease."

During the experiment, the team of investigators took out the nucleus of unfertilized egg cells and inserted the nucleus of the egg cell of another donor. As a result, the egg cell had the genome of the donor but not the original mitochondrial DNA. The researchers believe that the experiment showed that nucleus transfer could help lower the temperature of the egg. They were then able to artificially cultivate the egg cell through parthenogenesis and stem cell lines were taken from a blastocyst that developed. The lines grew for over a year and produced adult cell types, including heart cells, neurons, and pancreatic beta cells. The scientists were also unable to detect the genome´s original mitochondria, which demonstrated that the group of researchers could limit future family members from developing particular inheritable diseases.

"Women who carry mutant mitochondrial DNA may no longer have to worry that their children will become sick. This technique may allow us to provide women with a therapeutic option that will prevent these disorders," noted the study´s co-author Mark Sauer, who is the vice chairman of the Obstetrics and Gynecology as well as chief of Reproductive Endocrinology at Columbia University Medical Center, in a prepared statement.

Moving forward, the researchers plan to work towards clinical application of the technique. Currently, there are limited treatment options to prevent mitochondrial disease. Some women who have family history of mitochondrial disease may even decide to not have children or complete in vitro fertilization with eggs from a donor.

"These findings epitomize the goals and aspirations of The New York Stem Cell Foundation — to accelerate and find cures, and prevent diseases," remarked Susan L. Solomon, who serves as the CEO of The New York Stem Cell Foundation, in the statement. "This research underscores the importance of interdisciplinary collaborations in which close partnerships between researchers and clinicians allow for tremendous advances that previously were not possible."

The team of investigators also hopes to be able to produce more eggs cells that are free of mitochondrial diseases.

"We often know too late that a patient runs the risk of passing on defective mitochondria to her children. It is absolutely devastating to a patient and her family," concluded Dr. Michio Hirano, MD, who works as a professor of Neurology and co-director of the Adult Muscular Dystrophy Association clinic at Columbia University Medical Center, in the statement. "This new technique offers an effective solution by ensuring only healthy mitochondria are present in the egg cells."