A developing human egg.
What’s the News: Since the 1950s, it’s been generally accepted that women are born with all the eggs they will ever have. One gets doled out with each menstrual cycle, and when they run out, you get menopause. But a smattering of papers over the last decade or so have indicated that that dogma might be incorrect: scientists found cells in the ovarian tissue of female mice that appear capable of producing new eggs. Now, working with donated tissue, researchers have found similar cells in human ovaries.
Headlines hyping the find have been spreading across the web, and we feel compelled to point out that this paper doesn’t mean that we will be able to grow fresh new eggs in Petri dishes, and it doesn’t prove that in real, live women these cells actually mature into eggs that can develop into offspring. It does, however, provide an interesting chance to see whether egg production by these cells can be jump-started using drugs.
What’s the News: What if the egg is fine and the sperm is dandy, but you still can’t seem to have a baby? Couples who are having trouble conceiving can testify to the frustration of learning that there’s no clear reason for their infertility. Now, however, scientists have found a genetic mutation that makes outwardly normal sperm much less fertile, potentially explaining many such cases and suggesting new routes to conception.
Earlier today we noted that Robert Edwards won a 2010 Nobel Prize for his work developing in vitro fertilization. But more than three decades after Edwards’ work came to fruition with the first IVF child’s birth, the technique is still somewhat haphazard—two-thirds of the time, it doesn’t lead to a live birth. Now, with a new approach to watching the first day or two of an embryo’s existence, scientists may be able to take a leap forward in both their understanding of a life’s first moments and in the success rate of IVF.
In a study published in Nature Biotechnology, Connie Wong and colleagues watched nearly 250 embryos develop over six days. They made the videos like the one seen above using time-lapse photography at the microscopic level, which showed the key differences between successful and failed embryos.
Successful embryos had an initial cytokinesis, or division of the cell’s cytoplasm, lasting between 0 and 33 minutes, a gap between first and second cell divisions lasting 7.8 – 14.3 hours, and an interval between second and third cell divisions of 0 – 5.8 hours. The pattern was so uniform that it was possible to automate the analytical process, using a computer algorithm to predict whether embryos would go on to develop successfully. [Nature]
Robert G. Edwards.
Edwards’ work creating in vitro fertilization led to the birth of four million babies, and now it has garnered him the Nobel Prize.
Dr. Edwards, a physiologist who spent much of his career at Cambridge University in England, spent more than 20 years solving a series of problems in getting eggs and sperm to mature and successfully unite outside the body. His colleague, Dr. [Patrick] Steptoe, was a gynecologist and pioneer of laparoscopic surgery, the method used to extract eggs from the prospective mother. Dr. Steptoe, who presumably would otherwise have shared the prize, died in 1988. [The New York Times]
Louise Brown, the first baby conceived through in vitro fertilization, will be turning 32 this year, and most people born through IVF are still younger than 30. While the technique has become commonplace for would-be parents struggling with fertility problems, doctors note that the long-term effects of the procedure still aren’t certain. Now, some scientists are saying they see slight differences in the DNA expression of people born via IVF, and that it’s possible they could be at higher risk for conditions like cancer or diabetes later in life.
Says lead researcher Carmen Sapienza said “By and large these children are just fine, it’s not like they have extra arms or extra heads, but they have a small risk of undesirable outcomes” [The Guardian]. Rather, the team found a very subtle impact. In 75 IVF babies and 100 naturally conceived ones, they examined 700 genes that particularly interested the researchers because they are linked to fat cell development, insulin signaling, and other functions associated with diseases for which people tend to be at higher risk as they age. The scientists checked DNA methylation, a modification to DNA which affects gene expression, and found that 5 to 10 percent of IVF babies had abnormal patterns of methylation.
Sapienza’s team published the study in October in Human Molecular Genetics, but his work is picking up attention after he spoke at the American Association of the Advancement of Science meeting in San Diego.
Even after people struggling with infertility have found a happy ending with in vitro fertilization, another complicated dilemma remains: what to do with extra fertilized embryos created during treatment. A new study found that more than 400,000 of these embryos are currently chilling in the freezers of fertility clinics around the country; while some of those are being stored for women who want more children, many others are being kept on ice because women have qualms about disposing of them. And while some women are willing to donate their embryos to research, that option frequently isn’t offered.
Ethical and personal considerations have led some people to a stalemate. For nearly 15 years, Kim and Walt Best have been paying about $200 a year to keep nine embryos stored in a freezer at a fertility clinic at Duke University — embryos that they no longer need, because they are finished having children but that Ms. Best cannot bear to destroy, donate for research or give away to another couple…. “There is no easy answer,” said Ms. Best, a nurse. “I can’t look at my twins and not wonder sometimes what the other nine would be like” [The New York Times].