In fertility breakthrough, Israeli scientists reverse aging process in human eggs

Researchers from the Hebrew University of Jerusalem say anti-viral drugs lead to older eggs behaving "like they are in their 20s."

 	Development of human embryo at five stages. Contributors: Science Museum, London. (photo credit: SCIENCE MUSEUM, LONDON)
Development of human embryo at five stages. Contributors: Science Museum, London.
(photo credit: SCIENCE MUSEUM, LONDON)

In what could mark a major breakthrough for fertility treatments, Israeli scientists say that they have successfully managed to reverse the aging mechanism in eggs using antiviral drugs.

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Aging mechanism now reversible 

Led by molecular biologist Dr. Michael Klutstein, head of the Chromatin and Aging Research Lab in the faculty of Dental Medicine at the Hebrew University of Jerusalem, a team of researchers managed to successfully identify one of the aging mechanisms that prevent egg cells from successfully maturing.

“We found that this aging mechanism is reversible and we can treat it,” Klutstein told The Media Line.

The scientists’ findings were recently published in the peer-reviewed scientific journal Aging Cell. The research was carried out by doctoral student Peera Wasserzug-Pash, in collaboration with clinicians from Hadassah Medical Center and Shaare Zedek Medical Center in Jerusalem.

The findings mark a significant breakthrough in available fertility treatments. 

 Doctoral student Peera Wasserzug-Pash, left, and Dr. Michael Klutstein, head of the Chromatin and Aging Research Lab in the Faculty of Dental Medicine at the Hebrew University of Jerusalem. (credit: HEBREW UNIVERSITY) Doctoral student Peera Wasserzug-Pash, left, and Dr. Michael Klutstein, head of the Chromatin and Aging Research Lab in the Faculty of Dental Medicine at the Hebrew University of Jerusalem. (credit: HEBREW UNIVERSITY)

A growing number of women in many parts of the world are delaying having children until their late thirties and into their forties. After the age of 35, women’s eggs begin to rapidly deteriorate and in-vitro fertilization (IVF) treatments become less effective.

A potentially game-changing discovery

“This research allows us to understand how human eggs age, which is important also for understanding how aging occurs in others areas,” Wasserzug-Pash, who conducted the research, told The Media Line. “We can affect this aging mechanism with drugs and with [medical] intervention. We’ve gone one step forward in being able to help women suffering from age-related infertility. They will suffer less, have to go through fewer difficult procedures, and run into fewer disappointments when it comes to trying to conceive and start a family.”

“The only treatment that exists today to address the issue of age-related infertility is prevention,” she said. “You either have children when you’re young or you freeze your eggs.”

Slowing down the aging process is no easy feat, however. Egg cells accumulate damage to their genetic material over time, starting when a woman is at a relatively young age. By the time a woman reaches her late 30s, her eggs have accrued enough damage to prevent them from properly maturing or being fertilized.

Roughly half of our genome is composed of virus-like sequences or fragments of viruses that can cause significant damage to the DNA if they manage to activate themselves through expression. This was discovered by Barbara McClintock, who was awarded a Nobel Prize for her work in 1983.

“Those parts are very damaging, like viruses,” Klutstein explained. “There are mechanisms in the cells to prevent these viruses from expressing themselves. With age, what happens is that the repression mechanism gets broken and then they start making copies of themselves. What we get is damage to older eggs.”

Klutstein’s team found that there is a way to prevent this damage from happening, thereby reversing the aging processes at work in egg cells.

“If we use drugs that prevent these viruses from operating, and these are just antiviral drugs, then we stop this mechanism from happening and slow down the aging process,” he explained.

Researchers in the lab examined both mice and human egg cells that were taken from several different age groups. They measured the levels of viruses, levels of DNA damage, how much the eggs matured in the test tube (an IVF setting), and how the chromosomes of the DNA looked under the microscope after the antiviral drug was administered.

In all cases, the older oocytes, or eggs, that had received the antiviral drug appeared to be younger than the ones that had not been treated.

“In general, in humans, old oocytes are ones above the age of 35 and the acute ones are over 40,” Klutstein said. “After treatment, they behaved more like eggs in their 20s.”

The next step will be to establish the correct protocol for treating human eggs in an IVF setting, as well as ensure that the treatment does not negatively affect the embryo. The promising treatment is still years away from being available.

“This is very experimental still, but we want to make a drug out of it,” Klutstein noted. “Like with any other drug, they take a long time to develop.”