Connie K. Ho for redOrbit.com Your Universe Online

Researchers from Oregon Health and Science University (OHSU) recently revealed a new gene therapy method that can successfully prevent particular inherited diseases. The scientists worked under the colleges Oregon National Primate Research Center as well as the Department of Obstetrics and Gynecology at OHSU and were able to complete the procedure in human cells. With the findings of the study, the new gene therapy will provide new methods for clinical trials with human subjects in the future.

The gene therapy was originally developed as research in nonhuman primates to stop diseases associated with gene defects in the cell mitochondria.

Previous research conducted in the Mitalipov lab in 2009 using monkey egg cells proved that this procedure was possible and that healthy baby monkeys were the result. This research illustrates that the procedure is also possible in human cells and the resulting egg cells were normal and healthy upon observation, explained researcher Shoukhrat Mitalipov in a Frequently Asked Question (FAQ) section on the OHSU website.

The results of the study were recently featured in the online edition of the journal Nature as well as presented at the American Society for Reproductive Medicine Conference in San Diego this past week.

Cell mitochondria contain genetic material just like the cell nucleus and these genes are passed from mother to infant, commented Mitalipov in a prepared statement. When certain mutations in mitochondrial DNA are present, a child can be born with severe conditions, including diabetes, deafness, eye disorders, gastrointestinal disorders, heart disease, dementia and several other neurological diseases. Because mitochondrial-based genetic diseases are passed from one generation to the next, the risk of disease is often quite clear. The goal of this research is to develop a therapy to prevent transmission of these disease-causing gene mutations.

In the study, 106 human eggs were obtained from study volunteers from OHSUs Division of Fertility and Reproductive Endocrinology. The team of investigators transferred the nucleus from one cell to another with the help of a method developed during another research project with nonhuman primates. The cells cytoplasm that helps the mitochondria was swapped out and, by fertilizing the eggs, the researchers were able to observe whether the transfer was effective in helping the cells undergo normal development. The scientists then discovered that the method was successful in replacing defective mitochondria that had mutated DNA.

As described above, there are four steps to the new gene therapy. According to the Los Angeles Times, in the last step, the egg is fertilized when a sperm cell is injected into it and this process is known as intracytoplasmic sperm injection (ICSI). The fertilized egg would develop into blastocyts, which are early-stage embryos. If the method was developed into a treatment, the blastocysts would then be re-implanted in the womb of the mother and forms into a healthy baby.

Using this process, we have shown that mutated DNA from the mitochondria can be replaced with healthy copies in human cells, noted Mitalipov in the statement. While the human cells in our study only allowed to develop to the embryonic stem cell stage, this research shows that this gene therapy method may well be a viable alternative for preventing devastating diseases passed from mother to infant.

According to the article in Nature, the method was successful when the researchers utilized frozen egg cells. A health baby monkey was born as a result of the replacement of mitochondria in a frozen/thawed monkey egg cells. The second part of the study focused on preservation through freezing. After being harvested from a donor, egg cells only stay viable for a short duration of time. Freezing allowed the donor cell and the mothers cell to be viable during the procedure. However, the process didnt work as smoothly for human eggs as it did for monkey eggs and the scientists believe that the method was effective enough to produce a minimum of two viable embryos from each treatment cycle.

See the article here:
Mutated Mitochondrial DNA Can Be Replaced With Healthy Copies In Human Cells

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