Tiny embryos, big discovery: Australian scientists investigate a new way to assess embryo health
Melbourne IVF study to be presented at Europe's largest reproductive medicine conference explores a future way to identify embryos at higher risk of chromosome abnormalities without directly testing them.
Scientists at Melbourne IVF have taken an important step towards developing a future non-invasive tool that could help identify embryos at higher risk of chromosome abnormalities, with a pilot study finding that embryos with chromosome abnormalities consume energy differently from embryos with the correct number of chromosomes.
The pilot study found that embryos with the correct number of chromosomes consumed significantly more glucose than embryos with chromosome abnormalities, providing new evidence that an embryo's metabolism may reflect its underlying chromosome health.
The findings will be presented at the European Society of Human Reproductive and Embryology (ESHRE) Annual Meeting, where researchers say the work represents an important proof of concept.
Every healthy embryo contains the correct number of chromosomes, which carry the genetic instructions needed for normal development. Sometimes embryos develop with an extra or missing chromosome, known as aneuploidy.
These chromosome imbalances disrupt how cells function, forcing them to work under stress and changing the way they produce and use energy. Scientists refer to this as "aneuploid stress."
Kathryn Gurner, Melbourne IVF scientist said: "For many years we've known that embryos with chromosome imbalances behave differently, but we're now beginning to understand why.
"An extra or missing chromosome doesn't simply change the DNA. It changes how the whole cell functions, placing it under stress and altering the way it produces energy," Dr Gurner said.
Rather than examining the chromosomes themselves, researchers investigated whether these stressed embryos could be identified by measuring non-invasively how much glucose they consumed while growing in the laboratory.
At the blastocyst stage, glucose is an important fuel source for the developing embryo, and previous research has shown that metabolic activity can be linked to an embryo's health and developmental potential.
The researchers found that embryos with the correct number of chromosomes consistently consumed more glucose than embryos with chromosome abnormalities.
Dr Gurner said: "Rather than looking directly at the chromosomes, we're investigating whether we can detect the stress those cells experience simply by measuring what nutrients the embryo consumes.
"The exciting finding from this pilot study is that we can see metabolic differences between embryos with the correct number of chromosomes and those with chromosome imbalances,” said Dr Gurner.
While the findings are still at an early stage, researchers believe they could eventually help make IVF care more personalised.
Currently, the main way to determine whether an embryo has the correct number of chromosomes is through preimplantation genetic testing for aneuploidy (PGT-A), a procedure that involves taking a small biopsy of the embryo for genetic analysis. PGT-A is generally recommended only for selected patients, such as some older women or those with particular clinical indications.
Melbourne IVF researchers hope that, in the future, analysing the way an embryo uses energy could become an additional, non-invasive tool to help identify embryos showing signs of chromosome abnormalities, supporting discussions between patients and their fertility specialist about whether further genetic testing, such as PGT-A, may be beneficial.
"Our long-term goal isn't to replace PGT," Dr Gurner said.
"We're exploring whether metabolic analysis could help identify embryos that may be at higher risk of chromosome abnormalities and, in the future, help guide which patients might benefit from further testing."
"For example, a younger patient wouldn't routinely be offered PGT, but if their embryos showed metabolic changes consistent with aneuploidy (chromosome imbalances), that could help inform discussions with their fertility specialist."
While the findings are encouraging, they are based on an early-stage pilot study. Larger studies are now underway to better understand how chromosome abnormalities affect an embryo's metabolism and to determine whether this approach could one day be translated into routine IVF care.
Professor David Gardner, Scientific Director of Melbourne IVF and Virtus Health’s Group Director of ART, Scientific Innovation & Research said: "IVF has come an extraordinary long way since the birth of the world's first IVF baby almost 50 years ago, but we're still learning more about these remarkable embryos.
"At the blastocyst stage, an embryo is smaller than a full stop on a printed page and contains only around 100 cells. Every new technology that helps us better understand these tiny embryos has the potential to improve how we care for patients in the future," Professor Gardner said.
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