Leukemia inhibitory factor in human reproduction

Objective: To describe the clinical findings, expressions, interactions, and clinical implications of leukemia inhibitory factor (LIF) in human reproduction. Design: Review of published articles. Setting: Clinical development unit of biotechnology company. Intervention (s): None. Result(s): In the endometrium, LIF is expressed in a menstrual cycle-dependent manner, with the highest level occurring at the time of implantation. LIF is also detected in uterine flushing, and its level is significantly lower in women with unexplained infertility. Likewise, endometrial explants derived from women with unexplained infertility showed reduced levels of LIF secretion. Binding of LIF to LIF receptor and gp130 activates signal transduction pathways. LIF receptor is expressed in endometrium, oocytes, and blastocysts. Cytotrophoblasts cultured in the presence of LIF differentiate toward an anchoring extravillous phenotype. Conclusion(s): On the basis of reports gathered from animal and human studies, LIF appears to play an important role in implantation and in the establishment of pregnancy. (Fertil Steril (R) 2001;76:1091-6. (C) 2001 by American Society for Reproductive Medicine.).