The endometrium is receptive to the embryo during a restricted window in the mid-secretory phase. My objectives were to develop a minimally-invasive endometrial sampling method for gene expression profiling, and to identify genes differentially expressed in the receptive phase. Twenty-three normo-ovulatory women underwent uterine fluid aspiration during the pre-receptive (LH+2) and receptive (LH+7) phase of the same natural cycle. RNA was extracted, reverse transcribed, amplified and hybridized to whole-genome microarrays. Unsupervised hierarchical clustering revealed self-segregation of pre-receptive and receptive samples. Importantly, profiling by uterine fluid aspiration was representative of biopsy. An unpaired t-test with a false discovery rate of 0.05 and a Δ threshold of 4-fold identified 245 unique transcripts as differentially expressed in the receptive phase. NanoString analysis validated 96% of these genes. This approach will now allow us to correlate expression of these candidate biomarkers to implantation outcomes, towards the development of clinical assays predictive for endometrial receptivity.

The endometrium is receptive to the embryo during a restricted window in the mid-secretory phase. My objectives were to develop a minimally-invasive endometrial sampling method for gene expression profiling, and to identify genes differentially expressed in the receptive phase. Twenty-three normo-ovulatory women underwent uterine fluid aspiration during the pre-receptive (LH+2) and receptive (LH+7) phase of the same natural cycle. RNA was extracted, reverse transcribed, amplified and hybridized to whole-genome microarrays. Unsupervised hierarchical clustering revealed self-segregation of pre-receptive and receptive samples. Importantly, profiling by uterine fluid aspiration was representative of biopsy. An unpaired t-test with a false discovery rate of 0.05 and a Δ threshold of 4-fold identified 245 unique transcripts as differentially expressed in the receptive phase. NanoString analysis validated 96% of these genes. This approach will now allow us to correlate expression of these candidate biomarkers to implantation outcomes, towards the development of clinical assays predictive for endometrial receptivity.

<p>ABSTRACT</p><p>A defect implantation process is the major reason for unexplained infertility. Estrogen andprogesterone are steroid hormones preparing the endometrium for implantation. They mediatetheir effect through their receptors: estrogen receptor alpha and beta and progesteronereceptor A and B, respectively. Leukemia inhibitory factor (LIF), which is also important forimplantation, mediates its effect through LIF receptor and the coreceptor, gp130, and is downregulated by suppressors of cytokine signaling 1. The aim of the study was to compare thelevels of the steroid hormone receptors and LIF related factors in the endometrium of twogroups of women with the diagnosis unexplained infertility: one that became pregnant afterassisted reproduction and one that did not become pregnant. Before treatment of thesewomen, endometrial mRNA was collected during the window of implantation in themenstrual cycle. The levels of specific mRNAs were measured with real-time PCR. Womenwho had become pregnant had a significantly higher level of steroid hormone receptors. Thus,these proteins seem to be important for a pregnancy and may be suitable as receptivitymarkers.</p>

ABSTRACT A defect implantation process is the major reason for unexplained infertility. Estrogen andprogesterone are steroid hormones preparing the endometrium for implantation. They mediatetheir effect through their receptors: estrogen receptor alpha and beta and progesteronereceptor A and B, respectively. Leukemia inhibitory factor (LIF), which is also important forimplantation, mediates its effect through LIF receptor and the coreceptor, gp130, and is downregulated by suppressors of cytokine signaling 1. The aim of the study was to compare thelevels of the steroid hormone receptors and LIF related factors in the endometrium of twogroups of women with the diagnosis unexplained infertility: one that became pregnant afterassisted reproduction and one that did not become pregnant. Before treatment of thesewomen, endometrial mRNA was collected during the window of implantation in themenstrual cycle. The levels of specific mRNAs were measured with real-time PCR. Womenwho had become pregnant had a significantly higher level of steroid hormone receptors. Thus,these proteins seem to be important for a pregnancy and may be suitable as receptivitymarkers.