Researchers from Kato Ladies’ Clinic in Tokyo transplanted ovaries from young mice into aging female mice. They observed that this method made the mice fertile again and also revived the behavior and augmented their life span. Life span of mice was increased by 40 percent due to successful ovarian transplant.
Limited women undergo ovarian cancer; however some of them have been more successful as compared to others. Researchers say that further analyses are required before marking down that ovarian transplant had similar effects among women. It specifically involved waiting until patients became older.
Dr Noriko Kagawa, Associate Director for Research at the Kato Ladies’ Clinic in Tokyo shares, “At present ovarian transplants are performed with the aim of preserving a woman’s fertility after cancer treatment for instance, or of extending her reproductive lifespan. However, the completely unexpected extra benefit of fertility-preserving procedures in our mouse studies indicates that there is a possibility that carrying out similar procedures in women could lengthen their lifespan in general”.
In order to understand this better researchers conducted two mouse experiments. In the first experiment they removed both ovaries from young female mice and transferred it to six older mice that were too old to be fertile. In the second experiment one ovary was extracted from the young mice and transplanted into eight aged mice. These mice’s normal life span is knon to be 548 days and face menopause at about 525 days old.
It was identified that mice who received transplant became fertile again while the control group did not. In the first experiment mice got back to normal reproductive cycles that lasted for more than 80 days. In the second experiment these cycles lasted for 130 days.
Dr Kagawa elucidates, “All the mice in both experiments that had received transplants resumed the normal reproductive behavior of young mice. They showed interest in male mice, mated and some had pups. Normally, old mice stay in the corner of the cage and don’t move much, but the activity of mice that had had ovarian transplants was transformed into that of younger mice and they resumed quick movements. Furthermore, the lifespan of the mice who received young ovaries was much longer than that of the control mice: the mice that had received two ovaries lived for an average of 915 days, and the mice that had received one ovary, for an average of 877 days. The newest of our data show the life span of mice that received transplants of young ovaries was increased by more than 40%.”
He further shares, “The results show that transplanted normal ovaries from young mice can function in old, infertile mice, making them fertile again, but, in addition, extending their lifespan. Women who have ovarian tissue frozen at young ages, perhaps because they are about to embark on cancer treatment, can have their young ovarian tissue transplanted back when they are older. Normally we would be doing this simply to preserve their fertility or to expand their reproductive lifespan. However, our mice experiment suggests that this might also improve overall longevity. Further research has to be conducted before we can know whether or not this is the case.”
The main reason as to why ovarian transplant augmented the life span of mice was not known. Researchers anticipate it may be because transplants were stimulating the continuation of normal hormonal functions. They expect doctors and patients to know that women have chances when faced with cancer treatment that could destroy their fertility.
Dr Kagawa reveals “We have been successful in getting frozen ovaries to function completely normally after thawing and transplantation. So this should no longer be considered an ‘experimental’ procedure. Ovarian transplantation is the proper and necessary accompaniment to otherwise sterilizing treatment for young cancer patients. We must not neglect to freeze and save at least one of their ovaries before cancer treatment.”
These researchers worked in partnership for 6 years with Dr Sherman Silber, from St Luke’s Hospital, in St Louis, Missouri (USA), who has performed a number of successful ovarian transplants in women. Mainly because either they were about to be treated for cancer or because they had not yet found the right partner in life. Future analysis will include identifying if it will be possible for a woman to have a transplant using an ovary that is not her own and with limited drugs to lower the body’s natural immune response to what it perceives as a foreign body. In order to attain mature eggs that may be used for IVF they are observing culturing follicles in ovarian tissue in the laboratory.
These findings will be presented at the 26th annual meeting of the European Society of Human Reproduction and Embryology in Rome.