<p>About 30 % of all infertile couples suffer from infertility of an unexplained cause. Leukemia inhibitory factor (LIF) is a glycoprotein produced by the endometrium and is an important cytokine in the implantation process. LIF exerts its biological functions through heterodimerization of its two receptors: LIF receptor (LIFR) and gp130. Point mutations in the LIF gene have been associated with female infertility. The aim of this study was to investigate whether single nucleotide polymorphisms (SNPs) in the genes of LIFR and gp130 could cause reduced fertility in women. To this end, 115 samples from women diagnosed with unexplained infertility and 191 samples from fertile women were studied. Three SNPs in the gp130 gene and two SNPs in the LIFR gene were analyzed using real-time PCR. One significant difference and a tendency to difference were detected in the gp130 gene for women with unexplained infertility. There were no differences in the LIFR gene variations. In conclusion, polymorphisms in gp130, and thereby disturbances in the LIF pathway, could be one cause for infertility in women diagnosed with unexplained infertility.</p>

About 30 % of all infertile couples suffer from infertility of an unexplained cause. Leukemia inhibitory factor (LIF) is a glycoprotein produced by the endometrium and is an important cytokine in the implantation process. LIF exerts its biological functions through heterodimerization of its two receptors: LIF receptor (LIFR) and gp130. Point mutations in the LIF gene have been associated with female infertility. The aim of this study was to investigate whether single nucleotide polymorphisms (SNPs) in the genes of LIFR and gp130 could cause reduced fertility in women. To this end, 115 samples from women diagnosed with unexplained infertility and 191 samples from fertile women were studied. Three SNPs in the gp130 gene and two SNPs in the LIFR gene were analyzed using real-time PCR. One significant difference and a tendency to difference were detected in the gp130 gene for women with unexplained infertility. There were no differences in the LIFR gene variations. In conclusion, polymorphisms in gp130, and thereby disturbances in the LIF pathway, could be one cause for infertility in women diagnosed with unexplained infertility.

Impaired implantation and placental development have been implicated in several disorders of pregnancy such as unexplained miscarriage, preeclampsia, and intrauterine growth retardation. Insulin-Like Growth Factor (IGF)-II has previously been shown to promote blastocyst development and placental growth and function. We were interested in how IGF-II interacts with other factors throughout blastocyst development, implantation and placentation in the mouse to improve pregnancy outcome. In vitro embryo culture increases the risk of pregnancy complications associated with poor placentation. Recent research has focussed on optimising the culture conditions to more resemble that of the in vivo environment. IGF-II, Urokinase Plasminogen Activator (uPA) and Plasminogen individually have all been shown to be important for embryo development. However, it is likely that a combination of factors is required to counteract the negative effects of in vitro culture. Here we show that IGF-II, uPA and Plasminogen, in combination, significantly improve mouse blastocyst hatching rates and implantation rates on day 8 and doubles the number of mothers that are pregnant after embryo transfer. Following implantation, IGF-II is suggested to play a role in promoting placental development and function. We demonstrate that IGF-II is co-localised with both IGF receptors throughout early pregnancy in trophoblasts and in the developing blood vessels and adjacent stromal cells in the mesometrial decidua. This suggests that IGF-II may play a role in both decidual angiogenesis and placentation. We suggest that perhaps murine trophoblasts secrete molecules such as IGF-II to promote angiogenesis in the decidua early in pregnancy to compensate for their shallow invasion and allow for adequate trophoblast remodelling later in pregnancy. The first trimester human placenta experiences a low oxygen environment. The Hypoxia-Inducible Factors (HIFs) mediate the response to low oxygen, inducing genes such as IGF-II. Currently, the role of oxygen in mouse placentation, the mechanisms by which HIFs promote placentation or their interaction with IGF-II in the placenta is unknown. Here, we demonstrate that the early mouse implantation site is exposed to low oxygen levels similar to those seen in humans and expresses HIF-1 protein. We were interested then in the interaction between IGF-II, oxygen and HIFs in trophoblasts in vitro. Prolonged exposure to low oxygen reduced trophoblast outgrowth, and increased Tpbp mRNA levels, suggesting commitment to the spongiotrophoblast lineage. Interestingly, we found that antisense (as) Hif-1 may mediate the response to prolonged hypoxia in murine trophoblasts. Importantly, Hif-1 and Hif-2 were differentially regulated by oxygen and IGF-II in cultured trophoblast cells suggesting a novel interaction between IGF-II and oxygen. In conclusion, it appears that IGF-II is a central growth factor which interacts with other molecules to regulate a wide variety of process in early pregnancy to promote blastocyst development, implantation and placentation. The results outlined in this thesis demonstrate a novel interaction between IGF-II, uPA and Plasminogen in promoting blastocyst development and implantation which may be used to improve pregnancy outcome following ART. In addition, we have also identified a novel interaction between IGF-II, oxygen and the HIF system which may regulate trophoblast function. This has important implications not only for placental research, but also for cancer research. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1326731 / Thesis (Ph.D.) -- University of Adelaide, School of Paediatrics and Reproductive Health, 2008

Impaired implantation and placental development have been implicated in several disorders of pregnancy such as unexplained miscarriage, preeclampsia, and intrauterine growth retardation. Insulin-Like Growth Factor (IGF)-II has previously been shown to promote blastocyst development and placental growth and function. We were interested in how IGF-II interacts with other factors throughout blastocyst development, implantation and placentation in the mouse to improve pregnancy outcome. In vitro embryo culture increases the risk of pregnancy complications associated with poor placentation. Recent research has focussed on optimising the culture conditions to more resemble that of the in vivo environment. IGF-II, Urokinase Plasminogen Activator (uPA) and Plasminogen individually have all been shown to be important for embryo development. However, it is likely that a combination of factors is required to counteract the negative effects of in vitro culture. Here we show that IGF-II, uPA and Plasminogen, in combination, significantly improve mouse blastocyst hatching rates and implantation rates on day 8 and doubles the number of mothers that are pregnant after embryo transfer. Following implantation, IGF-II is suggested to play a role in promoting placental development and function. We demonstrate that IGF-II is co-localised with both IGF receptors throughout early pregnancy in trophoblasts and in the developing blood vessels and adjacent stromal cells in the mesometrial decidua. This suggests that IGF-II may play a role in both decidual angiogenesis and placentation. We suggest that perhaps murine trophoblasts secrete molecules such as IGF-II to promote angiogenesis in the decidua early in pregnancy to compensate for their shallow invasion and allow for adequate trophoblast remodelling later in pregnancy. The first trimester human placenta experiences a low oxygen environment. The Hypoxia-Inducible Factors (HIFs) mediate the response to low oxygen, inducing genes such as IGF-II. Currently, the role of oxygen in mouse placentation, the mechanisms by which HIFs promote placentation or their interaction with IGF-II in the placenta is unknown. Here, we demonstrate that the early mouse implantation site is exposed to low oxygen levels similar to those seen in humans and expresses HIF-1 protein. We were interested then in the interaction between IGF-II, oxygen and HIFs in trophoblasts in vitro. Prolonged exposure to low oxygen reduced trophoblast outgrowth, and increased Tpbp mRNA levels, suggesting commitment to the spongiotrophoblast lineage. Interestingly, we found that antisense (as) Hif-1 may mediate the response to prolonged hypoxia in murine trophoblasts. Importantly, Hif-1 and Hif-2 were differentially regulated by oxygen and IGF-II in cultured trophoblast cells suggesting a novel interaction between IGF-II and oxygen. In conclusion, it appears that IGF-II is a central growth factor which interacts with other molecules to regulate a wide variety of process in early pregnancy to promote blastocyst development, implantation and placentation. The results outlined in this thesis demonstrate a novel interaction between IGF-II, uPA and Plasminogen in promoting blastocyst development and implantation which may be used to improve pregnancy outcome following ART. In addition, we have also identified a novel interaction between IGF-II, oxygen and the HIF system which may regulate trophoblast function. This has important implications not only for placental research, but also for cancer research. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1326731 / Thesis (Ph.D.) -- University of Adelaide, School of Paediatrics and Reproductive Health, 2008