Why do women over 35 have more difficulty getting pregnant? After discovering one of the causes of age-related female infertility, researchers at the University of Montreal Hospital Research Centre (CRCHUM) suggest that it will be possible in the future to improve the quality of the eggs of older patients by intervening on the cell cycle level.
In a study published in the journal Developmental Cell, CRCHUM researcher Greg FitzHarris and Aleksandar Mihajlovic, a postdoctoral fellow in his lab and first author of the study, reveal in aged mouse eggs (oocytes) that some chromosomes are slower to move during meiosis, a crucial phase of cell division.
These laggards contribute to an uneven chromosomal distribution and therefore to the formation of cells with an abnormal number of chromosomes. This abnormality, called aneuploidy, is one of the major causes of infertility and explains, in part, why older women have difficulty becoming pregnant and carrying a pregnancy to term.
“To give the slowest chromosomes time to reach their destination, we artificially prolonged meiosis with a chemical. Using high-definition imaging techniques, we found that this slowing down before cell division limited aneuploidy,” says Greg FitzHarris, a professor at Université de Montréal.
In the medium term, this discovery, which is still in the basic research stage and conducted in the laboratory on mice, could be used in the clinic to increase the performance of eggs used during in vitro fertilization. Extensive efficacy, safety and security testing will be required before such an approach is adopted.
Almost one in six Canadian couples is affected by infertility. This number has doubled since the 1980s.
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About this study
The article “Distinct classes of lagging chromosome underpin age-related oocyte aneuploidy in mouse,” by Aleksandar Mihajlovic and colleagues, was published August 23, 2021 in Developmental Cell. Funding for the study was provided by the Canadian Institutes of Health Research, the Fonds de recherche du Québec-Santé and the Fondation Jean-Louis Lévesque.
About the CRCHUM
The University of Montreal Hospital Research Centre (CRCHUM) is one of North America’s leading hospital research centres. It strives to improve adult health through a research continuum covering such disciplines as the fundamental sciences, clinical research and public health. Over 1,850 people work at the CRCHUM, including more than 550 researchers and more than 460 graduate students. chumontreal.qc.ca/crchum
About Université de Montréal
Deeply rooted in Montreal and dedicated to its international mission, Université de Montréal is one of the top universities in the French-speaking world. Founded in 1878, Université de Montréal today has 13 faculties and schools, and together with its two affiliated schools, HEC Montréal and Polytechnique Montréal, constitutes the largest centre of higher education and research in Québec and one of the major centres in North America. It brings together 2,400 professors and researchers and has more than 67,000 students. umontreal.ca
Journal
Developmental Cell
Method of Research
Experimental study
Subject of Research
Animals
Article Title
Distinct classes of lagging chromosome underpin age-related oocyte aneuploidy in mouse
Article Publication Date
23-Aug-2021
COI Statement
The authors declare no competing interests.