Islamabad - An experimental technique that involves removing, freezing, and later transplanting ovarian tissue appears to be safe and can help about one third of women to have babies. But experts say more research is needed to validate the results.

The procedure is intended for women who’ve had cancer who wish to preserve their fertility, since cancer treatments such as chemotherapy and radiation can harm the ovaries. It typically involves removing one ovary and cutting it into strips before freezing the tissue. Years later, cancer survivors can undergo a graft of some of the thawed-out tissue onto their remaining ovary. For the study, researchers followed 41 women from Denmark who underwent the procedure between 2003 and 2014. The women’s average age when the tissue was removed and frozen was close to 30. The average age of the first transplant was 33. Among the 32 women in the study who wanted children, 10 became pregnant and gave birth. “Once we transplant the ovarian tissue, it takes about four to five months for the ovary to get restarted,” said Dr Claus Yding Andersen of Copenhagen University Hospital, the study’s senior author.

In some cases, the transplanted tissue lasted up to a decade, much longer than the scientists had predicted. The ovarian tissue that kept working so long probably had more eggs to begin with, said Mark Fenwick, a lecturer in reproductive and developmental medicine at Sheffield University, in South Yorkshire, England. He said mothers and babies required close monitoring although no potential problems linked to the technique have been noted so far.

In the study, three women later experienced a cancer relapse, but Andersen said that didn’t appear to be linked to the transplant.

“This technique still needs to be further validated, but the results are reassuring,” said Dr. Yacoub Khalaf, director of the Assisted Conception Unit at Guy’s Hospital in London, who is also working to refine the procedure. “It offers hope to people who have no other alternative.”

Currently, women preparing for cancer treatment might have eggs or embryos frozen for later use, but for this procedure, Dr. Jane Stewart of the British Fertility Society said the technique won’t be suitable for everyone and that doctors need to be careful about selecting which patients to treat. “I think patients would definitely want (the option of transplanted ovarian tissue) and there is a lot of future potential, but this isn’t ready to be rolled out tomorrow,” Stewart said.

Scientists create old cells

The new technique, which yields cells resembling those found in older people’s brains, will help scientists who are studying age-related diseases like Alzheimer’s and Parkinson’s. More recently stem cells have increasingly been used to study various diseases in humans skin cells can be taken from people and turned into induced pluripotent stem cells, which have the ability to become any cell in the body.

This technique has enabled brain cells to be created for the purposes of studying conditions like Alzheimer’s disease but even when skin cells are taken from an older person, this does not guarantee that stem cells with “older” properties can be produced.

This is because the induced pluripotent stem cell process involves resetting epigenetic signatures in older cells to match younger signatures. Epigenetic signatures are patterns of chemical marks on DNA that dictate what genes are expressed.

This resetting made studying the aging of the human brain difficult, since researchers could not create the characteristics of older brain cells.

The scientists collected skin cells from 19 people, aged from birth to 89, and prompted them to turn into brain cells using both the induced pluripotent stem cell technique and the direct conversion approach. The researchers then compared the patterns of gene expression in the resulting neurons with cells taken from autopsied brains.

In the induced pluripotent stem cell method, the patterns in the neurons were the same, regardless of the age of the individual from whom the samples were taken.

Now that the direct conversion of skin cells to neurons has been shown to retain signatures of age, the researchers expect the technique to become a valuable tool for studying aging. And, while the current work only tested its effectiveness in creating brain cells, they suspect a similar method will enable the creation of aged heart and liver cells as well.