Histologic dating of the endometrium: accuracy, reproducibility, and practical value

Hotspots and frontiers in luteal phase defect research: An in-depth global trend bibliometric and visualization analysis over a 52-year period

Luteal phase defect (LPD) is a common female reproductive endocrine defect，which is associated not only with certain diseases but also with the menstrual cycle and fertility in women. With the development of assisted reproductive technology (ART) in recent years, the incidence of luteal phase defect is high among patients using assisted reproductive technology. The aim of this study was to evaluate worldwide research on luteal phase defects using bibliometric analysis. A total of 631 documents related to the study of luteal phase defect were identified over the last 52 years. The current status and trend of globalization can be comprehended by analyzing the annual number of publications, institutions, authors, countries and regions of corresponding authors, journals, influential luteal phase defect publications (which were highly cited), highly cited references in luteal phase defect publications (cocitation analysis) and keywords. The study results provide a comprehensive overview of the development of scientific literature and are of great significance for the future development of the field，especially infertility and early pregnancy loss.

A new method for endometrial dating using computerized virtual pathology

Endometrial dating (ED) is the process by which the menstrual cycle day is estimated and is an important tool for the evaluation of uterine status. To date, ED methods remain inaccurate and controversial. We demonstrate how the rise of computerized virtual histology changes the state of affairs and introduce a new ED method. We present the results of a clinical trial where magnified images of ex-vivo endometrial tissue samples were captured at different cycle days, together with measurements of serum hormone levels on the same day. Patient testimonies about their cycle day were also collected. Computerized image analysis, followed by statistical representation of the tissue features, allowed mathematical representation of the cycle day. The samples underwent ED histological assessment, which is currently the ED gold standard. We compared dating results from patient reports, serum hormone levels, and histology to establish their concordance level. We then compared histology-based ED with the new method ED in the secretory phase (i.e. post ovulation). The correlation coefficient between the two resulted in an R = 0.89 with a P-value of P < 10-4. The new method, Virtual Pathology Endometrial Dating (VPED), has the benefit of being a real time, in-vivo method that can be repeatedly applied without tissue damage, using a dedicated hysteroscope. One practical use of this method may be the determination of accurate real-time embryo transfer timing in IVF treatments.

Encapsulated VEGF121-PLA microparticles promote angiogenesis in human endometrium stromal cells

Background

In this study, Vascular Endothelial Growth Factor 121 expressed abundantly in endometrial stromal cells is encapsulated with poly-l-lactide and characterized the properties for endometrial angiogenesis. We studied the migration, proliferation and the protein levels of human immortalized endometrium stromal cells after treating the cells with recombinant Vascular Endothelial Growth Factor (200 and 500 nanogram), and poly-l-lactide loaded Vascular Endothelial Growth Factor 121 (day 1, 20 and 30). The present study explains endometrium angiogenesis because endometrium plays an important role in pregnancy.

Results

Migration and proliferation studies in endometrium cells proved the efficiency of Vascular Endothelial Growth Factor and poly-l-lactide loaded Vascular Endothelial Growth Factor 121. This proliferated and increased the migration of the cells in vitro and also activated the Protein kinase B, Phosphatidylinositol-4, 5-Bisphosphate 3-Kinase Catalytic Subunit Beta, α-Smooth muscle actin and vascular endothelial growth factor receptor 2 pathways. Western blot analysis showed the increased expression levels of kinases, smooth muscle actin and vascular endothelial growth factor receptor 2 after the treatment with Vascular Endothelial Growth Factor and poly-l-lactide loaded Vascular Endothelial Growth Factor 121 particles in comparison to the control group. The elevated levels of α-Smooth muscle actin in endometrium cells with Vascular Endothelial Growth Factor prove the regulation of angiogenesis in vitro.

Conclusion

Endometrium thickness is one of the important factors during implantation of embryo and pregnancy. Slow release of VEGF from PLA encapsulated microparticle further controls the endothelial cell proliferation and migration and helps in the promotion of angiogenesis. The combined effect studied in vitro could be used as a pro-angiogenic drug on further in vivo confirmation.

Canadian Consensus-based and Evidence-based Guidelines for Benign Endometrial Pathology Reporting in Biopsy Material

Standardized terminology has proven benefits in cancer reporting; in contrast, reporting of benign diagnoses in endometrial biopsy currently lacks such standardization. Unification and update on the lexicon can provide the structure and consistency needed for optimal patient care and quality assurance purposes. The Special Interest Group in Gynecologic Pathology of the Canadian Association of Pathologists-Association Canadienne des Pathologistes (CAP-ACP) embarked in an initiative to address the current need for consensus terminology in benign endometrial biopsy pathology reporting. Nine members of the Special Interest Group developed a guideline for structured diagnosis of benign endometrial pathology through critical appraisal of the available peer-reviewed literature and joint discussions. The first version of the document was circulated for feedback to a group of professionals in akin fields, the CAP-ACP Executive Committee and the CAP-ACP general membership. The final 1-page document included 17 diagnostic terms comprising the most common benign endometrial entities, as well as explanatory notes for pathologists. The proposed terminology was implemented in the practice of 5 pathologists from the group, who applied the guideline to all benign endometrial biopsies over a 2-wk period. A total of 212 benign endometrial biopsies were evaluated in this implementation step; the recommended terminology adequately covered the diagnosis in 203 cases (95.8%). A list of terminology for benign endometrial biopsy reporting, based on expert consensus and critical appraisal of the available literature, is presented. On the basis of our results of implementation at multiple centers, the proposed guideline can successfully cover the large majority of diagnostic scenarios. The document has the potential to positively impact patient care, promote quality assurance, and facilitate research initiatives aimed at improving histopathologic assessment of benign endometrium.

Endometrial human chorionic gonadotropin (hCG) expression is a marker for adequate secretory transformation of the endometrium

PURPOSE

Successful embryo implantation into the endometrium depends on embryonic characteristics and proper endometrial development. Reproductive medicine often focuses on embryo quality, whereas reliable diagnostic tests for endometrial receptivity are still needed. We previously found that human chorionic gonadotropin (hCG), one of the earliest proteins secreted by the embryo, was also expressed by the luteal phase endometrium around the implantation window. Here, we tested our hypothesis of endometrial hCG as an implantation marker.

METHODS

Endometrial biopsies and serum samples were taken from patients undergoing routine infertility diagnostics. Correlations of immunohistochemically detected endometrial hCG expression with adequate endometrial secretory transformation, the infiltration of CD45-positive leukocytes, clinical diagnostic parameters, and endometrial thickness were analyzed.

RESULTS

A highly significant correlation between the endometrial score, as a measurement for regular secretory transformation, and the intensity of hCG staining was found. The invasion of CD45-positive leukocytes increased with progressing endometrial secretory transformation and rising endometrial hCG expression. In addition, serum progesterone concentrations correlated with hCG expression by the endometrial glands.

CONCLUSIONS

Our results suggest endometrial hCG as a possible diagnostic parameter characterizing the endometrial secretory transformation and, thus, possibly also its implantation capability.

Microarray analysis on gene regulation by estrogen, progesterone and tamoxifen in human endometrial stromal cells

Epithelial stromal cells represent a major cellular component of human uterine endometrium that is subject to tight hormonal regulation. Through cell-cell contacts and/or paracrine mechanisms, stromal cells play a significant role in the malignant transformation of epithelial cells. We isolated stromal cells from normal human endometrium and investigated the morphological and transcriptional changes induced by estrogen, progesterone and tamoxifen. We demonstrated that stromal cells express appreciable levels of estrogen and progesterone receptors and undergo different morphological changes upon hormonal stimulation. Microarray analysis indicated that both estrogen and progesterone induced dramatic alterations in a variety of genes associated with cell structure, transcription, cell cycle, and signaling. However, divergent patterns of changes, and in some genes opposite effects, were observed for the two hormones. A large number of genes are identified as novel targets for hormonal regulation. These hormone-responsive genes may be involved in normal uterine function and the development of endometrial malignancies.

Localization and hormonal regulation of endometrial matrix metalloproteinase-26 in the rhesus macaque

BACKGROUND

The current understanding of hormonal regulation of matrix metalloproteinase-26 (MMP-26) in the primate endometrium is incomplete. The goal of this work was to clarify estrogen and progesterone regulation of MMP-26 in the endometrium of ovariectomized, hormone-treated rhesus macaques.

METHODS

Ovariectomized rhesus macaques (n= 66) were treated with estradiol (E(2)), E(2) plus progesterone, E(2) followed by progesterone alone or no hormone. Endometrium was collected from the hormone-treated animals during the early, mid- and late proliferative and secretory phases of the artificial menstrual cycle. MMP-26 expression was quantified by real-time PCR, and MMP-26 transcript and protein were localized by in situ hybridization and immunohistochemistry and correlated with estrogen receptor 1 and progesterone receptor (PGR).

RESULTS

MMP-26 was localized to glandular epithelium and was undetectable in the endometrial stroma and vasculature. MMP-26 transcript levels were minimal in the hormone-deprived macaques and treatment with E(2) alone did not affect MMP-26 levels. Treatment with progesterone both in the presence and absence of E(2) stimulated MMP-26 expression in the early and mid-secretory phases (P < 0.001). MMP-26 expression preceded decidualization of endometrial stroma. MMP-26 levels then declined to baseline in the late secretory phase (P < 0.01) despite continued E(2) plus progesterone treatment. Loss of detectable MMP-26 expression in the late secretory phase was correlated with late secretory phase loss of glandular epithelial PGR.

CONCLUSIONS

Endometrial MMP-26 expression is dependent on the presence of progesterone in the early secretory phase and then gradually becomes refractory to progesterone stimulation in the late secretory phase. In the macaque, MMP-26 is a marker of the pre-decidual, secretory endometrium. During the second half of the late secretory phase, and during decidualization, MMP-26 loses its response to progesterone concurrent with the loss of epithelial PGR. The decline in MMP-26 levels between the mid- and late secretory phases may play a role in the receptive window for embryo implantation.

KiSS-1 in the mammalian ovary: distribution of kisspeptin in human and marmoset and alterations in KiSS-1 mRNA levels in a rat model of ovulatory dysfunction

Kisspeptins, the products of the KiSS-1 gene acting via G protein-coupled receptor 54 (GPR54), have recently emerged as pivotal signals in the hypothalamic network triggering the preovulatory surge of gonadotropins and, hence, ovulation. Additional actions of kisspeptins at other levels of the hypothalamic-pituitary-ovarian axis have been suggested but remain to date scarcely studied. We report herein the pattern of expression of KiSS-1 and GPR54 in the human and nonhuman primate ovary and evaluate changes in ovarian KiSS-1 expression in a rat model of ovulatory dysfunction. KiSS-1 and GPR54 mRNAs were detected in human ovarian tissue and cultured granulosa-lutein cells. In good agreement, kisspeptin immunoreactivity was observed in cyclic human and marmoset ovaries, with prominent signals in the theca layer of growing follicles, corpora lutea, interstitial gland, and ovarian surface epithelium. GPR54 immunoreactivity was also found in human theca and luteal cells. Administration of indomethacin to cyclic female rats disturbed ovulation and resulted in a dramatic drop in ovarian KiSS-1, but not GPR54, cyclooxygenase-2 (COX-2), or progesterone receptor, mRNA levels at the time of ovulation; an effect mimicked by the selective COX-2 inhibitor NS398 and rescued by coadministration of PGE(2). Likewise, the stimulatory effect of human choriogonadotropin on ovarian KiSS-1 expression was partially blunted by indomethacin. In contrast, KiSS-1 mRNA levels remained unaltered in another model of ovulatory failure, i.e., the RU486-treated rat. In summary, we document for the first time the expression of KiSS-1/kisspeptin and GPR54 in the human and nonhuman primate ovary. In addition, we provide evidence for the ability of inhibitors of COX-2, known to disturb follicular rupture and ovulation, to selectively alter the expression of KiSS-1 gene in rat ovary. Altogether, our results are suggestive of a conserved role of local KiSS-1 in the direct control of ovarian functions in mammals.

Epithelial human chorionic gonadotropin is expressed and produced in human secretory endometrium during the normal menstrual cycle

The objective of this study was to determine whether beta human chorionic gonadotropin (hCG) (CGB) subunits and alpha hCG (CGA) subunits are expressed and the hCG dimer is produced in normal human cyclic endometrium. Endometrial specimens were collected for histological dating from women undergoing treatment in our division of human reproduction. RNA from normal secretory endometrium was extracted, and CGB and CGA gene expression was assessed by semiquantitative PCR. Adequate secretory endometrial specimens were homogenized using protease inhibitors. Proteins present in the supernatant were separated electrophoretically, and molecular hCG isoforms were detected by Western blot. The supernatant hCG concentrations were measured by ELISA. We characterized hCG and leukocytes in endometrial specimens by immunohistochemistry. Uterine flushing was performed to confirm endometrial hCG secretion into the uterine fluid. A full-length CGB mRNA encompassing the exon 1 promoter region and the structure exons 2 and 3 (including the C-terminal peptide) was expressed in normal secretory endometrial specimens (similar to CGA) during the early secretory phase of the menstrual cycle, up to an optimum at the midsecretory to late secretory phases. In homogenate supernatants obtained from normal secretory endometrium, hormone concentrations of dimeric hCG were approximately 5 mU per 10 mg of tissue, compared with considerably smaller concentrations of corresponding single free CGB subunit. Single chains of CGB, CGA, and dimeric molecular hCG isoforms were found in endometrial specimens by Western blot. Glandular endometrial hCG production is demonstrated immunohistochemically, with an increase toward the late secretory phase vs. the early secretory phase of the normal secretory menstrual cycle. However, glandular hCG release is diminished or absent in the dyssynchronous or missing endometrial secretory transformation. Endogenous endometrial hCG may be important for implantation and maintenance of pregnancy.