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Leukemia inhibitory factor in human reproduction
1Yale University School of Medicine, Department of Obstetrics and Gynecology, New Haven, CT 06520-8063, USA.
Insights
Leukemia inhibitory factor (LIF) plays a key role in human reproduction. This cytokine is expressed in the endometrium, fallopian tube, and ovarian follicle, influencing implantation and early embryonic development.
Area of Science:
- Reproductive biology
- Cytokine signaling
- Human reproduction
Background:
- Leukemia inhibitory factor (LIF) is a pleiotropic cytokine with diverse biological actions.
- LIF is known to regulate the growth and differentiation of various cell types, including embryonic stem cells.
- LIF is essential for successful embryo implantation in mice, and its role in human reproduction is increasingly recognized.
Purpose of the Study:
- To review the expression, regulation, and effects of LIF in the human endometrium, fallopian tube, and ovarian follicle.
- To elucidate the role of LIF in key reproductive processes such as implantation and early embryonic development.
Main Methods:
- Literature review and analysis of existing studies.
- Focus on expression patterns, regulatory mechanisms, and functional impacts of LIF in human reproductive tissues.
Main Results:
- Human endometrial LIF expression is cyclical, peaking during the implantation window (days 19-25).
- LIF receptor is expressed on human blastocysts, and LIF influences trophoblast differentiation, suggesting a role in implantation.
- LIF is present in the fallopian tube and ovarian follicle, with expression patterns linked to ovulation and potential ectopic implantation.
Conclusions:
- Growing evidence supports LIF's significant role in human reproduction.
- LIF influences critical events from ovulation through implantation and early embryonic development.
Problem:
Leukemia inhibitory factor (LIF) is a pleiotropic cytokine of the interleukin-6 family and has different biological actions in various tissue systems. Although named for its ability to inhibit proliferation of a myeloid leukemic cell line by inducing differentiation, it also regulates the growth and differentiation of embryonic stem cells, primordial germ cells, peripheral neurons, osteoblasts, adipocytes, and endothelial cells. LIF is crucial for successful implantation of the embryo in mice. Currently, there is an accumulation of data about the role of LIF in human reproduction.
Method Of Study:
This review of the literature and of our studies focuses on the expression, regulation, and effects of LIF in the human endometrium, fallopian tube, and ovarian follicle.
Results:
Human endometrium expresses LIF in a menstrual cycle-dependent manner. Maximal expression is observed between days 19 and 25 of the menstrual cycle, coinciding with the time of implantation. Various cytokines and growth factors induce endometrial LIF expression in vitro. LIF receptor is expressed in endometrial tissue throughout the menstrual cycle and on human blastocysts in a stage-dependent manner. Affecting the trophoblast differentiation pathway toward the adhesive phenotype, LIF plays a role in implantation. LIF is also expressed and secreted by the epithelial cells of the fallopian tube. Its increased expression in the tubal stromal cell cultures by the inflammatory cytokines suggests a link between salpingitis and ectopic implantation in the tube. The rising follicular fluid LIF level around the time of ovulation indicates that LIF may play a role in ovulatory events, early embryonic development, and implantation.
Conclusions:
There is growing evidence that LIF may be one of the entities that plays a role in human reproduction.