IVF can be a tense experience if you’re waiting to find out whether the treatment has been a success, but a new study finds zinc ‘fireworks’ from newly fertilised eggs are a good marker whether they will develop into an embryo.
Scientists from Northwestern Medicine conducted the study by activating an egg with sperm enzyme (by law real sperm is not allowed to be used in US research), which triggers a calcium increase. This in turn releases zinc from the egg, which binds with small molecule probes that emit light in radiant bursts, like in the video below. An even distribution of zinc around the egg will help it develop into a healthy embryo, so the more radiant the burst the better chances the egg will be a success.
The discovery was first made five years ago in mice, but the new research is the first time it has been successfully seen in a human egg.
“This is an important discovery because it may give us a non-invasive and easily visible way to assess the health of an egg and eventually an embryo before implantation,” says co-author Dr Eve Feinberg.
“There are no tools currently available that tell us if it’s a good quality egg. Often we don’t know whether the egg or embryo is truly viable until we see if a pregnancy ensues. That’s the reason this is so transformative.”
A good egg
Successful IVF treatment depends on the fertilised egg growin into a healthy embryo and this new research could open up new opportunities for finding out which eggs are the most likely to continue to grow once they have been implanted into the womb.
The next stage is to develop a tool that will enable clinicians to test for zinc blooms in the lab, allowing a non-invasive method of finding out how successful the IVF treatment has been and which egg is the best one to choose.
“We now know that the release of zinc at the time of fertilization is a conserved phenomenon,” says first author Francesca Duncan, who made the human zinc spark discovery. “(The study) will help us address one of the largest unanswered questions in reproductive medicine – what makes a good egg?”