title: Metabolites involved in cellular communication among human cumulus-oocyte-complex and sperm during in vitro fertilization.
abstract: BACKGROUND
  Fertilization is a key physiological process for the preservation of the species. Consequently, different mechanisms affecting the sperm and the oocyte have been developed to ensure a successful fertilization. Thus, sperm acrosome reaction is necessary for the egg coat penetration and sperm-oolema fusion. Several molecules are able to induce the sperm acrosome reaction; however, this process should be produced coordinately in time and in the space to allow the success of fertilization between gametes. The goal of this study was to analyze the metabolites secreted by cumulus-oocyte-complex (COC) to find out new components that could contribute to the induction of the human sperm acrosome reaction and other physiological processes at the time of gamete interaction and fertilization.
  
  
  METHODS
  For the metabolomic analysis, eighteen aliquots of medium were used in each group, containing: a) only COC before insemination and after 3 h of incubation; b) COC and capacitated spermatozoa after insemination and incubated for 16-20 hours; c) only capacitated sperm after 16-20 h in culture and d) only fertilization medium as control. Six patients undergoing assisted reproduction whose male partners provided normozoospermic samples were included in the study. Seventy-two COC were inseminated.
  
  
  RESULTS
  The metabolites identified were monoacylglycerol (MAG), lysophosphatidylcholine (LPC) and phytosphingosine (PHS). Analysis by PCR and in silico of the gene expression strongly suggests that the cumulus cells contribute to the formation of the PHS and LPC.
  
  
  CONCLUSIONS
  LPC and PHS are secreted by cumulus cells during in vitro fertilization and they could be involved in the induction of human acrosome reaction (AR). The identification of new molecules with a paracrine effect on oocytes, cumulus cells and spermatozoa will provide a better understanding of gamete interaction.
authors.affiliation: Department of Biotechnology, University of Alicante, 99, Carretera de San Vicente s/n, Alicante, 03016, Spain. mjose.gomez@ua.es.
authors.forename: María José
authors.initials: MJ
authors.lastname: Gómez-Torres
authors.affiliation: Department of Biotechnology, University of Alicante, 99, Carretera de San Vicente s/n, Alicante, 03016, Spain.|Instituto Bernabeu of Fertility and Gynecology, Alicante, 03016, Spain.
authors.forename: Eva María
authors.initials: EM
authors.lastname: García
authors.affiliation: Instituto Bernabeu of Fertility and Gynecology, Alicante, 03016, Spain.
authors.forename: Jaime
authors.initials: J
authors.lastname: Guerrero
authors.affiliation: Research Group on Quality, Safety and Bioactivity of Plant Foods, Food Science and Technology Department, CEBAS-CSIC, Espinardo (Murcia), Spain.
authors.forename: Sonia
authors.initials: S
authors.lastname: Medina
authors.affiliation: Department of Cell Biology and Histology, Faculty of Medicine, University of Murcia, Campus Mare Nostrum, Espinardo 30100 and IMIB, Murcia, Spain.
authors.forename: María José
authors.initials: MJ
authors.lastname: Izquierdo-Rico
authors.affiliation: Research Group on Quality, Safety and Bioactivity of Plant Foods, Food Science and Technology Department, CEBAS-CSIC, Espinardo (Murcia), Spain.
authors.forename: Ángel
authors.initials: Á
authors.lastname: Gil-Izquierdo
authors.affiliation: Institute of Materials Science of Aragon, CSIC-University of Zaragoza, 50009, Zaragoza, Spain.
authors.forename: Jesús
authors.initials: J
authors.lastname: Orduna
authors.affiliation: Institute of Materials Science of Aragon, CSIC-University of Zaragoza, 50009, Zaragoza, Spain.
authors.forename: María
authors.initials: M
authors.lastname: Savirón
authors.affiliation: Department of Cell Biology and Histology, Faculty of Medicine, University of Murcia, Campus Mare Nostrum, Espinardo 30100 and IMIB, Murcia, Spain.
authors.forename: Leopoldo
authors.initials: L
authors.lastname: González-Brusi
authors.affiliation: Department of Biotechnology, University of Alicante, 99, Carretera de San Vicente s/n, Alicante, 03016, Spain.|Instituto Bernabeu of Fertility and Gynecology, Alicante, 03016, Spain.
authors.forename: Jorge
authors.initials: J
authors.lastname: Ten
authors.affiliation: Instituto Bernabeu of Fertility and Gynecology, Alicante, 03016, Spain.
authors.forename: Rafael
authors.initials: R
authors.lastname: Bernabeu
authors.affiliation: Department of Cell Biology and Histology, Faculty of Medicine, University of Murcia, Campus Mare Nostrum, Espinardo 30100 and IMIB, Murcia, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Avilés
mesh_terms: D020101:Acrosome Reaction / Q000502:physiology; D002450:Cell Communication / Q000502:physiology*; D054885:Cumulus Cells / Q000166:cytology / Q000378:metabolism*; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D008244:Lysophosphatidylcholines / Q000378:metabolism; D008297:Male; D050178:Monoglycerides / Q000378:metabolism; D009865:Oocytes / Q000166:cytology / Q000378:metabolism*; D013075:Sperm Capacitation / Q000502:physiology; D013084:Sperm-Ovum Interactions / Q000502:physiology*; D013094:Spermatozoa / Q000166:cytology / Q000378:metabolism*; D013110:Sphingosine / Q000031:analogs & derivatives / Q000378:metabolism
chemical_list: D008244:Lysophosphatidylcholines; D050178:Monoglycerides; C012491:phytosphingosine; D013110:Sphingosine