A new study has revealed a pioneering new treatment that could slow down the menopause in women by allowing the ovaries to carry on working following female stem cell transplants which turn into mature eggs.
The results have also opened up the possibility of helping women with certain types of female infertility where eggs are not produced by the ovaries. The future objective is to use stem cell transplants to top up the availabilty of fresh eggs in infertile women.
It was not long ago, that female mammals were born with a reproductive system capable of storing around 2 million egg-producing follicles. However, this number is significantly reduced in humans with around 400,000 at the age of puberty, with significantly lower numbers at the menopause - not enough to reproduce.
However, only four years ago, scientists from America carried out successful experiments proving it was possible to take stem cells from an adult woman’s ovaies and grow them into mature egg cells.
In China they have gone one step further by enabling the isolation of stem cells from both mature and immature ovaries of mice, keep the cells in a controlled environment before placing them back into the infertile females and thus allowing them to give birth to healthy offspring.
Professor Azim Surani, of the Gurdon Institute at Cambridge University, commented that the findings of the study would be of great significance for women unable to produce mature eggs, “Sperm are produced continuously in men but the number of eggs in women is fixed at birth,” he said. “This study … suggests there are also stem cells present in ovaries that can be cultured in a dish, which can develop into viable eggs.”
There is a possibility that these stem cells could be isolated from a woman when she is younger, in order for her to have children later in life.
Professor Robin Lovell-Badge, of the Medical Research Council’s National Institute for Medical Research, said that if the results were positive, “it could provide a means to restore fertility to women who have few eggs or who have had to undergo cancer treatments, by isolating these cells, expanding their numbers … and keeping them frozen until needed for IVF”.
However he went on to say that the findings of the Nature Cell Biology had not addressed some vital questions, “Extraordinary claims require extraordinary evidence … to me this is a very incomplete piece of work…” he said. “This [study] will stimulate lots of activity in the scientific community. But what would be unfortunate is if this is hyped as a cure for female infertility.”