Influence of Cellular Lipids on Cryopreservation of Mammalian Oocytes and Preimplantation Embryos: A Review

Abstract

Lipids are among the most abundant and essential cell components. Specifically, cytoplasmic lipid droplets (LDs) play crucial roles in cellular energy homeostasis. The foci of this review are (1) the composition and roles of lipids during oocyte maturation and early embryonic development, (2) possible causes of cryoinjuries in lipid-rich oocytes/embryos, and (3) ways to overcome these detrimental effects. Recent reports show that LDs in oocytes and embryos are not only energy depots but also are active organelles, possessing many other functions. In addition, analysis of the current literature confirms that lipid phase transition followed by phase separation during cryopreservation is one of the major causes of cryodamage in lipid-rich oocytes and embryos. While LDs and cell membranes are sensitive to chilling and freezing conditions, recent advances in vitrification and delipidation of lipid-rich oocytes and embryos partly mitigate cryodamage. The multidisciplinary approach is critical to reveal mechanisms underlying cryodamage and provides a theoretical basis for optimal cryopreservation of lipid-rich oocytes/embryos.

Desiccation and supra‐zero temperature storage of cat germinal vesicles lead to less structural damage and similar epigenetic alterations compared to cryopreservation

“…Similar results were also reported on vitrified bovine oocytes (Chaves et al, 2017). This is not unexpected because lipids are known to be prone to cryoinjuries (Amstislavsky et al, 2019).…”

“…Similar results were also reported on vitrified bovine oocytes (Chaves et al, ). This is not unexpected because lipids are known to be prone to cryoinjuries (Amstislavsky et al, ). Although most studies focused on the impact of cryopreservation on cytoplasmic and mitochondrial membranes, nuclear envelope likely endures similar stress during freezing.…”

“…Both lipids and chromatin are vulnerable to freezing or dried conditions. Lipid aggregation, membrane damage, DNA breakage, and chromatin condensation have been reported in cryopreserved and/or drypreserved cells (Amstislavsky, Mokrousova, Brusentsev, Okotrub, & Comizzoli, 2019;Chen et al, 2001;Golan et al, 2018;Kopeika et al, 2015;Kratochvílová et al, 2018;Shahba et al, 2016). In addition, epigenetic regulation has putative long-lasting or even transgenerational effect in the offspring and therefore is a serious concern for assisted reproduction applications.…”

Oocytes, obesity, and omega-3 fatty acids

“…Another aspect to consider is the role of fatty acids in oocyte and embryo cryopreservation (5). Although the mechanism is not understood, it is well known that high lipid contents makes cryopreservation difficult in both oocytes and embryos causing cryo-damage.…”

The establishment of a Living Genome Resource Bank utilising genetic analysis and assisted breeding technology: a case study on the koala (Phascolarctos cinereus)

“…AI techniques have been successfully produced for several wildlife species, including; 14 species of non-domestic bovids, seven nondomestic cervids (Comizzoli, 2015) and three species of endangered gazelles (Garde et al, 2003). In vitro insemination, or IVF, is less commonly used in conservation as it involves specialised methods, which can vary greatly between species and can limit wildlife conservation (Amstislavsky et al, 2018;Comizzoli et al, 2000;Cordova et al, 2017).…”