Scientists Grow Human Egg Cells from Stem Cells in the Lab







Human egg cells that have been grown in a lab will soon be fertilized in a historic experiment that overturns the rules of reproduction, revolutionizes fertility — and could grant women an “elixir of youth” by banishing menopause.

American and British scientists from the Edinburgh University and the Harvard Medical School have produced the first human egg cells grown entirely in the laboratory from egg stem cells — “female germline” or “oogonial stem cells” (OSCs) — following the recent discovery of such stem cells that was, in itself, an earthshaking development in fertility science.

And as if that did not astonish enough, these lab-grown egg cells could be fertilized this year, if fertility authorities in the United Kingdom give the go signal.

The three back-to-back developments — the discovery of the oogonial stem cells, the creation of lab-grown human egg cells and their upcoming fertilization — are all momentous developments the field of fertility. Together, these three events:

  • Overturn 60 years of dogma in fertility.
  • Have the potential to revolutionize fertility treatment.
  • May lead to life-long fertility for women.
  • May reverse menopause in older women.

Overturning 60 years of dogma
Women are born with their full complement of egg cells which they gradually lose through life until they run out when they reach the menopause — that, at least was what scientists believed for the past 60 years.

Then in 2004, Dr. Jonathan Tilly of Harvard went up against this dogma by suggesting that there were active stem cells in the ovaries of mice that were capable of replenishing eggs throughout life.

In the succeeding years, a number of studies in lab mice proved him right, showing the existence of these “female germline” or “oogonial stem cells” (OSCs) in living mice. The stem cells were shown to be capable of producing further oocytes.

And as recently as February, a team of scientists from Harvard and the Massachusetts General Hospital in the United States, together with colleagues from Japan’s Saitama Medical University shocked the scientific community when they announced that they had discovered these same stem cells that can transform into new eggs in the ovaries of young women.

The team was led by Dr. Tilly, and the results of that pioneering research were published in the Feb. 26 issue of the journal Nature Medicine.

“This age-old belief that females are given a fixed ‘bank account’ of eggs at birth is incorrect,” Professor Tilly announced at time. “In fact, ovaries in adulthood are probably more closely matched to testes in adulthood in their capacity to make new germ cells, which are the special cells that give rise to sperm and eggs,” he said.

“Over the past 50 years, all the basic science, all the clinical work and all the clinical outcome was predicated on one simple belief — that is the oocyte pool, the early egg-cell pool in the ovaries was a fixed entity, and once those eggs were used up they cannot be renewed, replenished or replaced,” he pointed out then.

Female human germline cells or OSCs are specialized cells that can develop into ‘oocytes.’ In turn, these can develop into mature eggs or ‘ova’.

Back then, Professor Tilly’s team isolated OSCs from human ovaries, grew these into human oocytes, and matured them into human ova — all in the lab. But they weren’t able to test if these ova were fully functional because it would have been unethical to implant them in the mice that they were working on. Now, they are about to do make this test — by fertilizing these eggs.

To do so, Dr. Tilly is collaborating with Dr. Evelyn Telfer, a reproductive biologist at the Edinburgh University who was once skeptical of his research. Dr. Telfer has pioneered a technique for growing immature eggs cells into the fully “ripened” cells that can be fertilized.

Revolutionize fertility treatment, reverse menopause
Because of the dogma that women are born with all the egg cells they can ever produce, fertility scientists have been hampered in their work for many decades. They have only been able to work with mature human egg cells taken from women — and this meant that there has been a limit to the amount available for both in vitro fertilization and research.

Now that these oogonial stem cells have been discovered in humans — and if scientists can show that they can grow mature ova that are fully functional — this may open the door to better treatments for women who become infertile because of disease, or simply because they’re getting older.

What’s more, the findings have the potential to make women just as fertile in later life as men — or in short, to give them life-long fertility. This is bound to help with many women who are increasingly choosing to delay settling down and having children, wanting to establish themselves first financially and in terms of their careers.

The Independent also reports that some scientists think the findings could lead to producing an “elixir of youth” for women — a way of replenishing the ovaries of older women so that they don’t have to suffer the age-related health problems associated with the menopause.

From osteoporosis to heart disease, hot flashes to night sweats, irritability and mood swings to trouble sleeping at night, irregular periods to crashing fatigue, difficulty concentrating and disorientation, incontinence to aching muscles, headaches to hair loss, bleeding gums and tinnitus — the list of ailments associated with menopause is practically a litany of woes.

With menopause eradicated, older women will be able to retain the health they once enjoyed when they were younger, the scientists think.

Fertilizing the eggs grown from stem cells
Now Dr. Tilly’s and Telfer’s team is set to fertilize the lab-grown eggs cells, and is about to request for a license from UK’s fertility watchdog.

The investigators want to fertilize the egg cells with human sperm to prove that they are viable. “The aim will be to demonstrate that the eggs that we’ve generated in vitro are competent to form embryos and that’s the best test that an egg is an egg,” Dr. Richard Anderson of the Medical Research Council Centre for Reproductive Health, the British scientist who will be in charge of the clinical aspects of the work, tells The Independent.

But following stringent laws on human fertilization — any resulting embryos will be studied for up to 14 days only to see if they are normal. The law sets 14 days as the legal limit that embryos may be studied. Because they will be deemed experimental material, these early embryos will not be transplanted into a woman’s womb — but will either be frozen or allowed to perish.

Dr. Telfer has says she has already informally approached the Human Fertilisation and Embryology Authority (HFEA), and will submit a formal license application within the next few weeks.

“We hope to apply for a research license to do the fertilization of the in vitro grown oocytes within the IVF unit at the Edinburgh Royal Infirmary,” Dr. Telfer tells The Independent. “Could the fertilization take place this year? Yes, absolutely,” she says.

Mass cloning
The pioneering research is quickly gaining the displeasure of a number of fundamentalist Christian groups in cyberspace. In some blogs, citizens have expressed fears that by if a virtually unlimited supply of human eggs egg can be derived, this would lead to mass cloning experiments that, in turn, would allow scientists to overcome eventually the complexities that have so far thwarted the perfecting of the human cloning.

In these fears they are united with bioethicists and many global authorities. In August 2005, the United Nations adopted the UN Declaration on Human Cloning, which calls on members countries to adopt all measures needed to prohibit all forms of human cloning. The UN called for the blanket ban saying this was needed “inasmuch as (human cloning is) incompatible with human dignity and the protection of human life.”

At that time, 84 countries voted for the declaration, 34 voted against, and 37 abstained.

The declaration also called on States to:

  • Protect human life adequately in the application of life sciences
  • Prohibit the application of genetic engineering techniques that may be contrary to human dignity
  • Prevent the exploitation of women in the application of life sciences
  • Adopt and implement national legislation in that connection.

The declaration is not legally binding.

ADDITIONAL READINGS:
Stem Cell Cure for Female Infetility
Cosmetic Stem Cells: Side Effects and Health Risks
Stem Cell Therapy for Children