Progesterone Threshold Determines Nucleolar Channel System Formation in Human Endometrium

Research progress of endometrial receptivity in patients with polycystic ovary syndrome: a systematic review

Polycystic ovary syndrome (PCOS) is a neuroendocrine heterogeneous disease that frequently occurs in women of reproductive age, causing serious damage to the fertility, quality of life, and physical and mental health of patients. The current studies have proved that satisfactory endometrial receptivity is one of the conditions that must be met during the process of spermatovum position, adhesion and invasion, as well as the subsequent blastocyst division and embryo development. Women with PCOS may suffer a series of pathological processes such as changes in the expression levels of hormones and related receptors, imbalances in the proportion of miscellaneous cytokines, insulin resistance, low-grade chronic inflammation and endometrial morphological changes, which will damage endometrial receptivity from various aspects and obstruct fertilized egg nidation and embryonic development, thus causing adverse reproductive health events including infertility and abortion. This article reviews the research progress about characteristics and related influencing factors of endometrial receptivity in PCOS patients.

Presence of endometrial nucleolar channel systems at the time of frozen embryo transfer in hormone replacement cycles with successful implantation

OBJECTIVE

To detect nucleolar channel systems (NCSs) in cells in endometrial aspirations obtained immediately before embryo transfer during blastocyst hormone replacement therapy-frozen embryo transfer (HRT-FET) cycles without affecting implantation.

DESIGN

Prospective case series.

SETTING

University-affiliated fertility clinic.

PATIENTS

Five patients who underwent an HRT-FET cycle consented to lower uterine segment aspiration using an open-tip embryo transfer catheter during a routine mock transfer performed immediately before embryo transfer.

INTERVENTIONS

Exfoliated cells in the aspirated endometrial secretions were analyzed for the presence of NCSs using indirect immunofluorescence and, in one case, electron microscopy for unambiguous identification.

MAIN OUTCOME MEASURES

On the basis of a previous study, positive NCS status was defined as the presence of NCSs in at least 3 endometrial epithelial cells (EECs). The effect of endometrial aspiration on implantation and pregnancy outcomes was assessed.

RESULTS

Biochemical pregnancy, as evidenced by positive β-human chorionic gonadotropin, was seen in 5 of 5 patients, and clinical pregnancy was seen in 2 of 5 patients. NCSs were detected in exfoliated EECs of uterine secretions in 4 of 5 patient samples and could not be unequivocally identified in 1 of 5 patient samples, which was designated as indeterminate.

CONCLUSIONS

This is the first report of NCS detection in HRT-FET cycles in the absence of follicular development and ovulation. NCS status can be determined in exfoliated EECs of uterine secretions obtained at the time of embryo transfer while maintaining implantation. Our study furthers the goal of establishing whether individualized point of care testing of NCS status in HRT-FET cycles can determine optimal endometrial receptivity and improve pregnancy outcomes.

Nucleoplasmic Reticulum Formation in Human Endometrial Cells is Steroid Hormone Responsive and Recruits Nascent Components

The nuclei of cells may exhibit invaginations of the nuclear envelope under a variety of conditions. These invaginations form a branched network termed the nucleoplasmic reticulum (NR), which may be found in cells in pathological and physiological conditions. While an extensive NR is a hallmark of cellular senescence and shows associations with some cancers, very little is known about the formation of NR in physiological conditions, despite the presence of extensive nuclear invaginations in some cell types such as endometrial cells. Here we show that in these cells the NR is formed in response to reproductive hormones. We demonstrate that oestrogen and progesterone are sufficient to induce NR formation and that this process is reversible without cell division upon removal of the hormonal stimulus. Nascent lamins and phospholipids are incorporated into the invaginations suggesting that there is a dedicated machinery for its formation. The induction of NR in endometrial cells offers a new model to study NR formation and function in physiological conditions.

A historical review of blastocyst implantation research

Research development on blastocyst implantation was reviewed in three sections: primate implantation, ungulate farm animal implantation, and the general process of blastocyst implantation in small rodents. Future research directions of this area are suggested.

Minimum values for midluteal plasma progesterone and estradiol concentrations in patients who achieved pregnancy with timed intercourse or intrauterine insemination without a human menopausal gonadotropin

Objective

The aim of the study was to assess the lower limits of midluteal plasma progesterone and estradiol concentrations in patients who achieved pregnancy with timed intercourse or intrauterine insemination without a human menopausal gonadotropin stimulation.

Results

We included 297 pregnant cycles of 297 women and assessed midluteal plasma progesterone and estradiol concentrations and pregnancy outcomes, retrospectively. These cycles were compared with the non-pregnant cycles (406 cycles) of the same women who became pregnant. Mean midluteal plasma P4 and E2 concentrations were significantly (P < 0.01) higher in pregnant cycles (14.5 and 188.5 pg/mL) than in non-pregnant cycles (10.7 and 162.6 pg/mL). The 5 percentiles of progesterone and estradiol in pregnant cycles were 5.6 and 70.2 pg/mL, respectively. The lowest progesterone and estradiol levels in pregnant cycles were 2.3 and 23.4 pg/mL, respectively. In non-pregnant cycles, many women had low P4 levels that were less than 5.6 ng/mL. Subgroup analyses showed slight differences among the four groups, which may have been due to the ovarian function of each group. Miscarriage was not related to progesterone and estradiol concentrations. These values may be useful for the evaluation of necessary values for pregnancy with timed intercourse or intrauterine insemination.

Status of nucleolar channel systems in uterine secretions accurately reflects their prevalence-a marker for the window of implantation-in simultaneously obtained endometrial biopsies

OBJECTIVE

To assess whether nucleolar channel systems (NCSs) can be detected in exfoliated endometrial epithelial cells (EECs) of uterine secretions and whether such noninvasively determined NCS status is associated with significant NCS prevalence in simultaneously obtained endometrial biopsies.

DESIGN

Prospective study (December 2015-February 2017).

SETTING

University-affiliated and private fertility clinics.

PATIENT(S)

Luteal-phase patients of reproductive age requiring endometrial biopsy for medical indications.

INTERVENTION(S)

Uterine secretion aspiration before endometrial biopsy. Cells in uterine secretions were spun onto slides and fixed. NCSs were identified and quantified in cells and paraffin-embedded tissue sections by indirect immunofluorescence.

MAIN OUTCOME MEASURE(S)

Comparison of NCS status of uterine secretions with NCS prevalence in biopsies. Based on NCS detection, uterine secretions were assigned a status of NCS-positive (n = 15) or NCS-negative (n = 7). NCS prevalence in biopsies was expressed as a percentage of NCSs per EECs.

RESULT(S)

NCSs can be detected in exfoliated EECs of uterine secretions. Median NCS prevalence in endometrial biopsies from patients with NCS-positive secretions was 41.9% (interquartile range [IQR], 21.1-53.9) versus 2.0% (IQR, 0-6.9) when secretions were NCS-negative. The NCS status of secretions identified a significant difference in NCS prevalence of simultaneously obtained biopsies.

CONCLUSION(S)

NCS status of secretions accurately reflects NCS prevalence of biopsies, a marker for the implantation window. As secretion aspiration is compatible with same-day ET, our study provides proof of principle for a minimally invasive approach to determine endometrial receptivity for timing frozen ET.

Shared mechanisms in physiological and pathological nucleoplasmic reticulum formation

The mammalian nuclear envelope (NE) can develop complex dynamic membrane-bounded invaginations in response to both physiological and pathological stimuli. Since the formation of these nucleoplasmic reticulum (NR) structures can occur during interphase, without mitotic NE breakdown and reassembly, some other mechanism must drive their development. Here we consider models for deformation of the interphase NE, together with the evidence for their potential roles in NR formation.