A new discovery by Israeli scientists could increase the chances of women suffering from infertility problems becoming pregnant through hormonal treatments. The scientists have succeeded in locating proteins involved in the reduction of the number of oocytes, or immature egg cells, over a woman’s lifetime and the aging of the ovaries. By neutralizing the effects of a specific protein, Interleukin-1, scientists hope to slow down the natural processes that destroy the egg cells - and thus increase the chances of a woman becoming pregnant.
The results of the research, which was conducted by a team led by Dr. Shiri Uri-Belpolsky at Sheba Medical Center in Tel Hashomer and Tel Aviv University, were published in the current issue of the American journal “Proceedings of the National Academy of Sciences.”
Female mammals, including women, are born with a limited reservoir of some seven million eggs, which diminishes gradually. “Females are subject to a biological clock that dictates the end of the reproductive lifespan at 50 years of age, on average,” the article states. But fecundity sharply decreases after age 30. The mechanism of how this biological clock works is still not understood completely.
“Over the past decade, a trend of postponing childbearing into advanced age has led to a corresponding upward trend in the number of in vitro fertilization (IVF) treatments. Inflammation has been reported to affect both IVF outcomes and the ovarian reserve adversely. Identifying a possible culprit, such as Interleukin-1, may offer new insight into the mechanisms responsible for oocyte loss as well as practical interventions,” wrote the scientists.
Blocking the Interleukin-1 proteins, which are key players in the body’s immune response system, could slow down the rate at which eggs are eliminated and improve IVF outcomes. This could be especially effective in older women, whose response to hormonal treatments is very low.
The connection between Interleukin-1 and fertility was discovered by accident in research on arterial sclerosis and liver tissue inflammation in mice. It turned out that mice in which the various forms of IL-1 proteins had been blocked continued to become pregnant at ages far more beyond those of the mice in the control group. That accidental finding led to the present research.
Other scientists involved in the research include Dr. Yehuda Kamari, Prof. Dror Harats, and Dr. Aviv Shaish from the Strassburger Lipid Center at Sheba; Prof. Ruth Shalgi from Tel Aviv University; and Dr. Efrat Eliyahu of Mount Sinai Medical Center in New York.