The Interleukin-1 System and Human Implantation

Authors

  • Carlos Simón MD,

    Corresponding author
    1. Instituto Valenciano de Infertilidad (IVI), and Department of Peadiatrics, Obstetrics and Gynaecology, Valencia University School of Medicine, Valencia, Spain
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  • Amparo Mercader,

    1. Instituto Valenciano de Infertilidad (IVI), and Department of Peadiatrics, Obstetrics and Gynaecology, Valencia University School of Medicine, Valencia, Spain
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  • Maria José Gimeno,

    1. Instituto Valenciano de Infertilidad (IVI), and Department of Peadiatrics, Obstetrics and Gynaecology, Valencia University School of Medicine, Valencia, Spain
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  • Antonio Pellicer

    1. Instituto Valenciano de Infertilidad (IVI), and Department of Peadiatrics, Obstetrics and Gynaecology, Valencia University School of Medicine, Valencia, Spain
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Instituto Valenciano de Infertilidad, Guardia Civil 23, Valencia-46020, Spain

Abstract

PROBLEM: Cytokines and growth factors are increasingly implicated in embryonic implantation. In the present study, we focus on the interleukin-1 system as an example of local regulator in human implantation.

METHOD: Three different approaches are considered. First, we present evidence demonstrating its presence, regulation, and relevance on the human endometrium. Second, we demonstrate the presence of the IL-1 system in the human embryo and the selective IL-1 release only when embryos were co-cultured with human endometrial epithelial cells (EEC) or EEC-conditioned media, indicating an obligate role of the endometrium in the regulation of the embryonic IL-1 system. Finally, we show data regarding the presence, hormonal regulation, and endometrial origin of IL-1α, IL-1β, and IL-1ra levels in the endometrial fluid inside the endometrial cavity. Specifically, we present the IL-1 intracavitary microenvironment surrounding the human embryo at the apposition phase.

RESULTS: This work suggests that the IL-1 system seems to be relevant for human endometrial and embryonic physiology. Furthermore, this family of molecules must be considered as a relevant paracrine language displayed by both partners that may be important to endometrial and embryonic crosstalk during embryonic implantation.

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