High-density lipoprotein metabolism and the human embryo.
BACKGROUND
High-density lipoprotein (HDL) appears to be the dominant lipoprotein particle in human follicular fluid (FF). The reported anti-atherogenic properties of HDL have been attributed in part to reverse cholesterol transport. The discoveries of the scavenger receptor class B type I (SR-BI) and the ATP-binding cassette A1 lipid (ABCA1) transporter have generated studies aimed at unraveling the pathways of HDL biogenesis, remodeling and catabolism. The production of SR-BI and ABCA1 knockout mice as well as other lipoprotein metabolism-associated mutants has resulted in reduced or absent fertility, leading us to postulate the existence of a human hepatic-ovarian HDL-associated axis of fertility. Here, we review an evolving literature on the role of HDL metabolism on mammalian fertility and oocyte development.


METHODS
An extensive online search was conducted of published articles relevant to the section topics discussed. All relevant English language articles contained in Pubmed/Medline, with no specific time frame for publication, were considered for this narrative review. Cardiovascular literature was highly cited due to the wealth of relevant knowledge on HDL metabolism, and the dearth thereof in the reproductive field.


RESULTS
Various vertebrate models demonstrate a role for HDL in embryo development and fertility. In our clinical studies, FF levels of HDL cholesterol and apolipoprotein AI levels were negatively associated with embryo fragmentation, but not with embryo cell cleavage rate. However, the HDL component, paraoxonase 1 arylesterase activity, was positively associated with embryo cell cleavage rate.


CONCLUSIONS
HDL contributes to intra-follicular cholesterol homeostasis which appears to be important for successful oocyte and embryo development.
Fujimoto
Victor Y
VY
Department of Obstetrics, Gynecology and Reproductive Sciences, University of California at San Francisco, San Francisco, CA 94115-0916, USA. fujimotov@obgyn.ucsf.edu
Kane
John P
JP
Ishida
Brian Y
BY
Bloom
Michael S
MS
Browne
Richard W
RW
D018528:ATP-Binding Cassette Transporters / Q000378:metabolism; D000818:Animals; D001692:Biological Transport; D002645:Chickens / Q000235:genetics; D004622:Embryo, Mammalian / Q000166:cytology / Q000502:physiology*; D005260:Female; D015571:Follicular Fluid / Q000378:metabolism; D006801:Humans; D008075:Lipoproteins, HDL / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D000071518:Liver X Receptors; D051379:Mice; D018345:Mice, Knockout; D009865:Oocytes / Q000254:growth & development / Q000378:metabolism; D057093:Orphan Nuclear Receptors / Q000235:genetics / Q000378:metabolism; D006080:Ovarian Follicle / Q000098:blood supply / Q000378:metabolism; D010053:Ovary / Q000378:metabolism; D051122:Scavenger Receptors, Class B / Q000378:metabolism
D018528:ATP-Binding Cassette Transporters; D008075:Lipoproteins, HDL; D000071518:Liver X Receptors; D057093:Orphan Nuclear Receptors; D051122:Scavenger Receptors, Class B