Potential effects of assisted reproductive technology on telomere length and telomerase activity in human oocytes and early embryos

Telomeres are repetitive DNA sequences at eukaryotic chromosome ends and function in maintaining genome integrity and stability. These unique structures undergo shortening due to various factors including biological aging, consecutive DNA replication, oxidative stress, and genotoxic agents. Shortened telomeres can be lengthened by the enzyme telomerase and alternative lengthening of telomeres in germ cells, early embryos, stem cells, and activated lymphocytes. If telomeres reach to critical length, it may lead to genomic instability, chromosome segregation defects, aneuploidy, and apoptosis. These phenotypes also occur in the oocytes and early embryos, produced using assisted reproductive technologies (ARTs). Thus, a number of studies have examined the potential effects of ART applications such as ovarian stimulation, culture conditions, and cryopreservation procedures on telomeres. Herein, we comprehensively reviewed impacts of these applications on telomere length and telomerase activity in ART-derived oocytes and embryos. Further, we discussed use of these parameters in ART centers as a biomarker in determining oocyte and embryo quality.

Automated summary

Telomeres are repetitive DNA sequences that protect the ends of eukaryotic chromosomes and play a crucial role in maintaining the integrity and stability of the genome. Shortening of telomeres can occur due to factors such as aging, DNA replication, oxidative stress, and genotoxic agents. However, telomeres can be lengthened by telomerase and alternative lengthening mechanisms. If telomeres become critically short, it can lead to genomic instability and abnormalities in cell division. The effects of assisted reproductive technologies (ARTs), such as ovarian stimulation, culture conditions, and cryopreservation procedures, on telomere length and telomerase activity in oocytes and embryos have been extensively studied. These parameters could potentially serve as biomarkers for assessing the quality of oocytes and embryos in ART centers.