title: Bovine cumulus cells protect maturing oocytes from increased fatty acid levels by massive intracellular lipid storage.
abstract: Metabolic conditions characterized by elevated free fatty acid concentrations in blood and follicular fluid are often associated with impaired female fertility. Especially elevated saturated fatty acid levels can be lipotoxic for several somatic cell types. The aim of this study was to determine the impact of elevated free fatty acid concentrations in follicular fluid on neutral lipids (fatty acids stored in lipid droplets) inside cumulus cells and oocytes and their developmental competence. To this end, cows were exposed to a short-term fasting period during final oocyte maturation. This resulted in elevated, but distinct, free fatty acid concentrations in blood and follicular fluid and a rise in the concentrations of in particular fatty acids with a chain length of 14-18 carbon atoms. Interestingly, elevated free fatty acid concentrations in follicular fluid resulted in a massive increase in the level of neutral lipids in cumulus cells, whereas the level of neutral lipid in oocytes was hardly affected. Furthermore, competence of oocytes to develop to the blastocyst stage after fertilization and culture of cumulus-oocyte-complexes of the experimental and control group was not different. In conclusion these data suggest that short-term elevated free fatty acid concentrations in follicular fluid do not harm oocyte developmental competence. We propose that the involvement of high levels of mobilized oleic acid in follicular fluid in combination with the induced lipid storage in cumulus cells serves to prevent harmful saturated fatty acid exposure to the oocyte.
authors.affiliation: Department of Farm Animal Health, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
authors.forename: Hilde
authors.initials: H
authors.lastname: Aardema
authors.forename: Francesca
authors.initials: F
authors.lastname: Lolicato
authors.forename: Chris H A
authors.initials: CH
authors.lastname: van de Lest
authors.forename: Jos F
authors.initials: JF
authors.lastname: Brouwers
authors.forename: Arie B
authors.initials: AB
authors.lastname: Vaandrager
authors.forename: Helena T A
authors.initials: HT
authors.lastname: van Tol
authors.forename: Bernard A J
authors.initials: BA
authors.lastname: Roelen
authors.forename: Peter L A M
authors.initials: PL
authors.lastname: Vos
authors.forename: J Bernd
authors.initials: JB
authors.lastname: Helms
authors.forename: Bart M
authors.initials: BM
authors.lastname: Gadella
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000187:drug effects / Q000378:metabolism; D002417:Cattle; D002478:Cells, Cultured; D054885:Cumulus Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D046149:Embryo Culture Techniques; D047108:Embryonic Development / Q000187:drug effects / Q000502:physiology; D005227:Fatty Acids / Q000378:metabolism* / Q000494:pharmacology; D005260:Female; D005307:Fertilization in Vitro; D015571:Follicular Fluid / Q000378:metabolism; D050356:Lipid Metabolism / Q000502:physiology*; D009865:Oocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D009866:Oogenesis / Q000187:drug effects / Q000502:physiology*
chemical_list: D005227:Fatty Acids
keywords: IVF; IVM; cows; embryo culture; in vitro fertilization; in vitro maturation; oocyte-follicle interactions; ruminants