Changed Bcl:Bax ratio in endometrium of patients with unexplained infertility

Impact of chronic endometritis in infertility: a SWOT analysis

Chronic endometritis is a pathology often associated with reproductive failure, but there are still no clear recommendations on whether its inclusion in the initial study of infertile couples is necessary. In this discussion paper, based on a SWOT (Strengths, Weaknesses, Opportunities, Threats) analysis, the different aspects of the repercussions of chronic endometritis in fertility are evaluated. To avoid possible subjectivity in the analysis and results of this study, the researchers followed the Oxford criteria for the evaluation of evidence. The results from the evaluation of the reviewed literature seem to indicate that, pending new evidence, it would be advisable not to include chronic endometritis in the initial baseline study before assisted reproduction in order not to delay other assisted reproduction treatments. However, it would be advisable in cases of repetitive implantation failure and pregnancy loss after having undergone IVF with viable embryos and before continuing with costly reproductive processes, since results could be improved. The development of randomized studies assessing the impact of antibiotic treatment as a possible therapeutic option in infertile women with chronic endometritis, as well as the possible impact on endometrial microbiota and receptivity/implantation, would allow for the establishment of more precise clinical guidelines in this regard.

Proteome analysis of endometrial tissue from patients with PCOS reveals proteins predicted to impact the disease

Polycystic ovary syndrome (PCOS) is a complex disease that causes an ovulatory infertility in approximately 10% of reproductive-age women. We searched for candidate proteins that might contribute to endometrial receptivity defects in PCOS patients, and result in adverse reproductive outcomes. Shotgun proteomics approach was used to investigate the proteome profile of the endometrium at the luteal phase in PCOS patients compared to healthy fertile individuals. Biological process and pathway analyses were conducted to categorize the proteins with differential expressions. Confirmation was performed for a number of proteins via immunoblotting in new samples. 150 proteins with higher abundance, and 46 proteins with lower abundance were identified in the endometrial tissue from PCOS patients compared to healthy fertile individuals. The proteins with higher abundance were enriched in protein degradation, cell cycle, and signaling cascades. Proteins with lower abundance in PCOS patients were enriched in extracellular matrix (ECM) composition and function, as well as the salvage pathway of purine biosynthesis. Metabolism was the most affected biological process with over 100 up-regulated, and approximately 30 down-regulated proteins. Our results indicate significant imbalances in metabolism, proteasome, cell cycle, ECM related proteins, and signaling cascades in endometrial tissue of PCOS, which may contribute to poor reproductive outcomes in these patients. We postulate that the endometria in PCOS patients may not be well-differentiated and synchronized for implantation. Possible roles of the above-mentioned pathways that underlie implantation failure in PCOS will be discussed. Our findings need to be confirmed in larger populations.

Chronic Endometritis: Old Problem, Novel Insights and Future Challenges

Chronic endometritis (CE) is a poorly investigated pathology which has been related to adverse reproductive outcomes, such as implantation failure and recurrent miscarriage. In this paper, we aim to provide an overview of diagnosis, etiology, pathophysiology and treatment of CE, its impact on endometrial microenvironment and its association with infertility. We present a narrative review of the current literatures, synthesizing the findings retrieved from searches of computerized databases. CE is more prevalent in infertile patients. Effective antibiotic treatment of CE seems to improve the pregnancy and live birth rate in patients with unexplained recurrent pregnancy loss (RPL), and increase ongoing pregnancy rate in patients with recurrent implantation failure. In order to increase the diagnostic accuracy, immunohistochemistry is recommended besides the conventional histology. In addition, hysteroscopy could be considered as gold standard tool for diagnosis, considering its high correlation with histological findings. CE, as the chronic inflammation of endometrium, is usually asymptomatic and probably underestimated. Interaction of bacteria with endometrial microenvironment promotes changes in leukocyte population, cytokine production and growth factors which support its negative impact on endometrial receptivity. Nevertheless, standardization of the criteria for histopathological diagnosis and immunohistochemistry technique needs to be defined.

Cytokine-induced expression of nitric oxide synthases in Chlamydia trachomatis-infected spontaneous aborters

Purpose: The aim of study was to evaluate expression of inducible nitric oxide synthase (iNOS), endothelial nitric oxide synthase (eNOS), interferon-gamma (IFN-γ), and tumor necrosis factor-alpha (TNF-α) in Chlamydia trachomatis (CT)-infected spontaneous aborters (SA). Materials and methods: Endometrial curettage tissue was collected from 140 SA (sporadic SA- 70; recurrent SA- 70) (Group I) and 140 age-matched controls (Group II) from Department of Obstetrics and Gynecology, Safdarjung Hospital, New Delhi, India. Polymerase chain reaction was performed for diagnosis of CT. The expression of iNOS/ eNOS/ IFN-γ/ TNF-α was assessed by real-time polymerase chain reaction (PCR). Results: 15.7% SA were CT-positive (Group I); none in controls. Sporadic spontaneous aborters (SSA) (n = 8/70), recurrent spontaneous aborters (RSA) (n = 14/70) diagnosed as CT-positive (Group-I). Significant upregulation of iNOS/ eNOS was found in CT-positive SSA/RSA compared with CT-negative SSA/RSA and healthy controls. TNF-α and IFN-γ were expressed in CT-positive SSA/RSA compared with negative SSA/controls. iNOS showed a significant strong positive correlation with TNF-α and IFN-γ in CT-infected SA. eNOS showed a significant positive correlation with TNF-α and no correlation with IFN-γ in CT-infected SA. TNF-α was positively correlated with IFN-γ. Conclusions: Significantly high expression of iNOS/ eNOS and proinflammatory cytokines affected pregnancy in CT-infected RSA, thereby implying that there occurs cytokine-induced expression of nitric oxide synthase (NOS).

Altered transcriptional regulation of cytokines, growth factors, and apoptotic proteins in the endometrium of infertile women with chronic endometritis

PROBLEM

Chronic endometritis (CE) is a poorly investigated and probably underestimated pathology, which may cause abnormal uterine bleeding (AUB), pain, and reproductive failures. Due to undefined symptoms and the normal presence of leukocytes in the endometrial mucosa, diagnosis may be missed. Fluid hysteroscopy is a reliable technique for diagnosing this pathology. Few data exist on the biochemical and paracrine alterations that occur in the endometrium of women diagnosed with CE. The aim of the study was to find molecular modification in endometrium related to CE.

METHOD OF STUDY

Sixteen women with hysteroscopic and histological diagnosis of CE and 10 healthy women as controls were enrolled. We compared the endometrial expression profile of 25 genes encoding proteins involved in the inflammatory response, proliferation, and apoptosis in endometrium during implantation window, using high-throughput real-time RT-PCR.

RESULTS

In women with CE, the endometrial expression of some genes was significantly altered. In particular, IGFBP1, BCL2, and BAX were up-regulated, while IL11, CCL4, IGF1, and CASP8 were down-regulated.

CONCLUSION

The altered gene endometrial expression may explain the impaired endometrial receptivity and the finding of endometrial hyperplastic lesions in women affected by CE.

Altered endometrial expression of endothelial nitric oxide synthase in women with unexplained recurrent miscarriage and infertility

Endothelial nitric oxide synthase (eNOS) has diverse roles in the female reproductive system including a role in blastocyst implantation. Aberrant expression of eNOS could therefore be significant in the pathogenesis of disorders of implantation. In this study, eNOS protein and mRNA levels in the endometrium of women with recurrent miscarriages, unexplained infertility and a control group were determined by compartmental quantitative immunohistochemistry and real-time reverse-transcription PCR. eNOS was found to be immunolocalized to all layers of the endometrium and vascular endothelium. eNOS protein was higher in glandular epithelium (P = 0.004) and luminal epithelium (P = 0.002), but not vascular endothelium and stroma, in women with recurrent miscarriage. Similarly, in women with unexplained infertility, eNOS was significantly higher (P < 0.03) in luminal epithelium but not in any other compartments compared with the control group. The levels of mRNA confirmed the protein data, demonstrating higher eNOS mRNA in the endometrium of women with recurrent miscarriage and unexplained infertility compared with controls. In conclusion, increased expression of eNOS in glandular and luminal epithelium of the endometrium in women with recurrent miscarriages and unexplained infertility suggests a detrimental effect of excess nitric oxide in endometrial receptivity and implantation.

Human endometrium ultrastructure during the implantation window: a new perspective of the epithelium cell types

The human endometrium is a hormonally regulated tissue that cyclically growths and differentiates in order to become a structure adequate for implantation. Molecular studies have shown some contradicting results and thus a reappraisal of the endometrium ultrastructure is warranted. In our study, endometrium biopsies were taken during the implantation window of 10 healthy women of reproductive age and analyzed using electron microscopy. Our results showed that during implantation window, the endometrial epithelium encompassed 4 cell types: microvilli-rich cells, pinopode cells, vesiculated cells, and ciliated cells. These cells showed signs of active communication with their external environment and neighboring cells, such as endocytosis, transcytosis and exocytosis. We highlighted important differences between surface and glandular epitheliums and characterized apocrine and holocrine secretion. It is likely that the features described reflect distinct functions in endometrium physiology that should be taken into account in the evaluation of the endometrium during the implantation window.