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Published on: August 15, 2014
Identification of apolipoprotein A1 in the human embryonic secretome
Lindsay M Mains1, Lane Christenson, Baoli Yang
1Department of Obstetrics & Gynecology, University of Iowa Hospitals & Clinics, Iowa City, Iowa, USA.
Objective:
To identify factors secreted by the human embryo and correlate levels with embryo morphology and pregnancy outcome.
Design:
A laboratory-based study of human embryo protein synthesis and secretion and a retrospective analysis of spent embryo culture media as it relates to pregnancy outcome.
Setting:
University-based academic IVF program.
Patient(S):
IVF patients who had donated cryopreserved human pronuclear-stage embryos. Patients undergoing fresh IVF cycles resulting in a blastocyst transfer who donated spent media drops.
Intervention(S):
In vitro embryo culture and collection of spent media.
Main Outcome Measure(S):
Protein analysis and identification by two-dimensional gel electrophoresis and mass spectrometry, ApoA1 quantification by ELISA, and mRNA analysis by quantitative reverse transcriptase-polymerase chain reaction.
Result(S):
By protein gel electrophoresis, apolipoprotein A1 (ApoA1) was increased in the culture media from good-quality blastocysts (n = 6 embryos) compared to either cleavage-arrested embryos (n = 6 embryos) or poor-quality blastocysts (n = 6 embryos) using spent media from culture days 4 and 5, respectively. Apolipoprotein A1 concentrations were 23.1% greater in day 5 spent culture media from good-grade blastocysts (n = 30) when compared to poor-grade embryos (n = 30). However, in a group of patients (n = 20) with transfer of two good-quality blastocysts, ApoA1 levels from day 5 spent media did not correlate with embryo implantation and pregnancy. Quantitative reverse transcriptase-polymerase chain reaction confirmed the presence of ApoA1 mRNA transcripts in human blastocysts.
Conclusion(S):
Apolipoprotein A1 is produced by human preimplantation embryos, and increased levels are present in spent culture media containing blastocysts of higher morphologic grade. These results suggest a role for lipoproteins in early embryologic development.
