If a heterosexual couple in their healthy twenties has intercourse every two or three days; without using contraceptive methods; their probability of pregnancy will be around 25% monthly. However, when you turn 30, that percentage begins to decline very slowly. Therefore, this is the main cause of sterility in women.
In a couple, the man is responsible for approximately a third of cases of sterility. At the same time, the advanced age of women is currently the main cause of sterility in women; according to the Spanish Fertility Society. From the age of 35, and especially since the age of 38, a woman’s chance of becoming pregnant plummets.
The key to determine sterility in women is in the ovaries
Those two almond-shaped organs are the key to solve the problem of sterility in women. This happens because the symptoms of ovaries premature aging begin at just 30 years. Because of this, there is a wide interest of millions of infertile women to have children. However, the difficulty in studying healthy ovaries has made these mechanisms remain an enigma.
The team of Spanish scientists, amongst them Juan Carlos Izpisúa reveals the different aspects of this phenomenon. Because of this, they open a new possibility for science. Increasing the period of fertility in women beyond that natural limit is still a remote possibility but is a step closer. According to the researcher himself, born in Hellín (Albacete) in 1960.
Juan Carlos Izpisúa’s team has studied human cells and the ovaries of eight macacas.
Scientists have come to the Xieerxin Institute of Biological Resources. This Chinese center near Beijing houses more than 4,000 monkeys dedicated to science. Izpisúa’s team removed the ovaries from four macaques of about five years and another four females of about 20 years. These ages would equal 16 and 60 years in women. The result is “the first thorough analysis of the aging of the ovaries in non-human primates”. According to Izpisúa, from the Salk Institute in La Jolla (USA).
Macaques and humans moved away from a common trunk about 25 million years ago. Compared to the 96 million years of evolution that separates people from mice, it is a much smaller gap. “I am convinced of the need to study aging in primates. If we really want that knowledge to be transferred to the clinic”. This was said by Izpisúa, whose laboratory has achieved amazing results in recent months. Such as monkey embryo cultured outside the uterus and the generation of artificial embryos from a single mouse-ear cell.
His team has studied 2,600 cells of the ovaries of the macacas with an unprecedented level of detail. They found a high level of oxidative stress. These harmful chemical reactions occur when cells consume oxygen to generate energy. The results confirm that oxidative stress plays a key role in the ovaries’ premature aging and sterility in women.
Importance of molecular study to retard sterility in women.
The DNA of each cell is an instruction manual. Therefore, it carries information to build the proteins that carry out almost all tasks of life. RNA is an intermediate molecule that allows you to read DNA and produces these proteins.
Izpisúa’s team studied all the RNA molecules in each cell. This allowed them to observe how at each stage of life the activity of genes changes. Researchers have observed that two genes, IDH1 and NDUFB10, possess antioxidant properties. Because of this, they shield some cell types of ovaries from oxidative stress. This natural shield is weakened with the passing of the years eventually causing sterility in women.
Women have donated cells to support studies on sterility.
The results have been confirmed with cells donated by women who have resorted to assisted reproduction techniques. The authors believe that these findings could also facilitate the diagnosis and treatment of sterility in women. Especially associated with ovarian aging. And even help fight diseases linked to this process, such as ovarian cancer.
“Our studies lay the foundations to evaluate the quality of the oocytes (the precursors of the ovules) and calculate the reproductive age of women”. This was said Concepción Rodríguez. She is co-author of the work and also a researcher at the Salk Institute. “Knowing the effects of oxidative damage is very important to counteract them”.
Some of these actions may include antioxidant interventions carried out to retard the ovaries premature aging process and sterility in women. Also, it can lead to the development of tools for oocytes rejuvenation. And to extend the fertility period of women,” adds the scientist. Izpisúa and Rodríguez are not only lab partners. They are also a couple.
The study was featured in an important scientific magazine.
The new study is on the cover of the prestigious specialized magazine Cell. With an illustration of two monkeys in a tree because this reflects “a classic Chinese story about the search for the fountain of youth,” Izpisúa explains. The two Spanish scientists are coauthors of the work along with twenty other colleagues. The majority of the scientists who participated in the study belong to the Chinese Academy of Sciences.
Why the study of sterility matter?
“This work will leave hundreds or thousands of projects,” applauds gynecologist Juan Antonio García Velasco. Because “the problem of postponing maternity is not only in Europe and the United States” it changes the approach. It begins to be worldwide. Our grandmothers had us with 20; our mothers, with 30; and now women are mothers at 40. “This study opens the possibility of stopping the aging of the ovaries or even reversing it“. García Velasco, director of the assisted reproduction clinic IVI Madrid said as much.
“Males produce sperm throughout their lives. Women are born with a certain number of oocytes. Because of this, from 35-38 years, occurs the most defective and abortions or children with Down syndrome, ” recalls the gynecologist. With this study, scientists could develop antioxidant supplements to give to young women who at the moment, do not want to have children. To stop the aging of their ovaries and retard sterility in women”. The study is at an early stage. However, this research of sterility in women has great social implications.