The findings of a landmark research conducted by scientists at the National Institute of Research and Reproductive Health (NIRRH), Parel, may re-define female ovarian biology and challenge the prevailing dogma that a woman is born with all the eggs she will ever produce with no way to replenish the supply, while men keep producing sperm throughout their lifetime.
According to the recently published study, called Stem Cell Interaction with Somatic Niche May Hold the Key to Fertility Restoration in Cancer Patients, fertility can be restored with the aid of stem cells identified in the ovaries.
Scientists have identified two distinct types of stem cells — Very Small Embryonic-like Stem Cells (VSELs), which do not divide rapidly, and slightly larger ovarian germ stem cells (OGSCs).
“Studies done on mice show that during chemotherapy, the OGSCs are destroyed because they actively divide like tumour cells, leading to infertility,” explained Dr Deepa Bhartiya, corresponding author of the article and scientist working at NIRRH, Stem Cell Biology Department.
She added, “The VSELs are resistant to cancer treatment, as they do not divide rapidly like tumour cells under normal circumstances. There is a possibility of developing eggs from them.”
The NIRRH research has opened new avenues for fertility restoration among cancer survivors. At present, the only option that cancer patients have is to preserve their eggs before undergoing chemotherapy and opt for assisted fertility reproduction post-treatment.
But with this study, the VSELs that are not damaged during chemotherapy, can be explored to help such patients experience parenthood.
Researchers claim that the identification of the VSELs and its consequent development into human eggs could also help to tackle the issue of advanced age-related infertility as well as the problem of early onset of menopause resulting in a loss of fertility in women.
“We are aiming to stimulate the resident VSELs in the infertile ovary and let nature take its course. We plan to undertake a pilot study to establish proof of this finding soon,” added Bhartiya.
Two other groups have reported on ovarian stem cells before. But NIRRH is the first to report that the ovarian and testicular VSELs in mice are possibly unaffected by chemotherapy and may be targeted to restore fertility in the future.
Dr Indira Hinduja, senior gynaecologist and infertility expert, said, “Around 25 per cent of all my infertile patients are suffering from a dysfunction of ovaries due to advanced age. Age will not be a bar or cause of infertility once these findings give us the anticipated results.”