Scientists have struggled to keep embryos alive in the lab for longer than a week because at the seven-day point an embryo must implant in the uterus in order to thrive and grow. But researchers have found a novel way to extend the amount of time by as much as an additional week—to 14 days total. The discovery could lead to a better understanding of the early stages of human development, and could also provide critical information on the causes of pregnancy complications such as miscarriage and birth defects.
The new findings were published May 4 in Nature and Nature Cell Biology. The researchers developed a technique to preserve mice embryos for longer by adding a mixture of amino acids, hormones and growth factors to blastocysts—cells at the pre-embryonic stage—to simulate life in utero. The blastocysts survived for a full two weeks.
After finding that the technique was effective on mice, the researchers successfully tried it out on human blastocysts.
This gave the researchers a closer look at what happens right at the moment the blastocysts came close to the two-week mark—a critical point, when the embryos begin to develop the early structures that will become vital organs.
However, this newest development in embryonic research has added more fuel to the ongoing bioethical debate on what time-frame embryonic research is considered to be appropriate. An accompanying editorial published in Nature suggests the scientific field should reconsider a current rule that forbids such research past the two-week mark.
"The 14-day rule has been effective for permitting embryo research within strict constraints—partly because it has been technologically challenging to break it," the authors write. "Now that the culturing of human embryos beyond 14 days seems feasible, more clarity as to how the rule applies to different types of embryo research in different jurisdictions is crucial."
The authors of the editorial argue that if these barriers are removed, this science could help to advance the field of fertility research and medicine, allowing for more effective fertility treatments and determine better ways to increase success rates for conception.
The medical community has struggled to update research guidelines at the same rapid pace that embryo research has developed. For example, in February, the Academies of Science, Engineering and Medicine released a report evaluating a new area of research that could result in three-parent embryos. That technique involves replacing damaged mitochondria in a woman trying to get pregnant with the same cellular material from another woman in order to help to prevent congenital conditions and diseases in a developing fetus. There are currently no guidelines for scientists pursuing this field, and many critics say more must be done to prevent embryo research from becoming the Wild West.
