Late chromosomes are one of the leading causes of infertility, study finds – .

Late chromosomes are one of the leading causes of infertility, study finds – .

Why do women over 35 have more difficulty getting pregnant? After discovering one of the causes of age-related female infertility, researchers at the Center hospitalier de l’Université de Montréal (CRCHUM) research center 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 Development cell, CRCHUM researcher Greg FitzHarris and Aleksandar Mihajlovic, postdoctoral fellow in his laboratory and first author of the study, reveal in aged mouse eggs (oocytes) that certain chromosomes are slower to move during meiosis, a crucial phase of cell division.

These laggards contribute to an uneven chromosome distribution and therefore to the formation of cells with an abnormal number of chromosomes. This abnormality, called aneuploidy, is one of the main causes of infertility and, in part, explains why older women have difficulty getting pregnant and carrying a pregnancy to term.

To give the slower 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. “

Greg FitzHarris, professor, University of Montreal

In the medium term, this discovery, still at the stage of basic research and carried out in the laboratory on mice, could be used in the clinic to increase the performance of the eggs used during in vitro fertilization. Thorough testing of effectiveness, safety and security will be necessary before adopting such an approach.

Almost one in six Canadian couples are affected by infertility. This number has doubled since the 1980s.

Journal reference:

Mihajlovic, IA, et al. (2021) Distinct classes of late chromosomes underlie age-related oocyte aneuploidy in mice. Development cell.


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