Variability in the expression of trophectodermal markers β-human chorionic gonadotrophin, human leukocyte antigen-G and pregnancy specific β-1 glycoprotein by the human blastocyst

• Published in: Human reproduction (Oxford) 1999-07, Vol.14 (7), p.1852-1858
• Main Authors: Jurisicova, Andrea, Antenos, Monica, Kapasi, Kubra, Meriano, James, Casper, Robert F.
• Format: Article
• Language: English
• Subjects: Apoptosis; Biological and medical sciences; Biomarkers; blastocyst; Blastocyst - cytology; Blastocyst - immunology; Blastocyst - metabolism; Cell Count; Chorionic Gonadotropin, beta Subunit, Human - genetics; Culture Media; Culture Techniques; Female; Fertilization in Vitro; Fundamental and applied biological sciences. Psychology; Gene Expression; Histocompatibility Antigens Class I - genetics; HLA Antigens - genetics; HLA-G Antigens; human leukocyte antigen-G; Humans; implantation; Molecular and cellular biology; Molecular genetics; Pregnancy; pregnancy specific β-1 glycoprotein; Pregnancy-Specific beta 1-Glycoproteins - genetics; β-human chorionic gonadotrophin
• ISSN: 0268-1161; 1460-2350
• DOI: 10.1093/humrep/14.7.1852

Improved culture conditions that support the development of human embryos to the blastocyst stage in vitro led to the prospect of blastocyst transfer to increase pregnancy rates. Thus, there is a need for characterization of possible biochemical markers able to predict the implantation potential of human blastocysts. In this study, the expression of three placental markers that are expressed prior to implantation, β-human chorionic gonadotrophin (HCG), human leukocyte antigen (HLA)-G and pregnancy specific β-1 glycoprotein (SP-1), was investigated. β-HCG transcript could be detected as early as the two-cell stage, which is one to two cleavage divisions earlier than previously reported. Both β-HCG and HLA-G transcripts could be detected in the majority of blastocysts, but their levels were highly variable. No association could be found between the amount of transcript for these genes, total cell number or cell death rate. Interestingly, there was a highly positive correlation between accumulation of β-HCG and HLA-G transcripts. SP-1 protein concentrations were assessed in the culture medium of blastocysts using enzyme-linked immunosorbent assay. There was a significant positive correlation between SP-1 concentrations and blastocyst cell numbers. Moreover, synthetic oviductal medium enriched with potassium resulted in an SP-1 concentration twice as high as that observed using human tubal fluid medium. These data suggest that SP-1 may be used to select blastocysts with higher cell number, possibly resulting in higher pregnancy rates.