Evaluation of Lipopolysaccharide and Interleukin-6 as Useful Screening Tool for Chronic Endometritis.

Universal diagnostic criteria for chronic endometritis (CE) have not been established due to differences in study design among researchers and a lack of typical clinical cases. Lipopolysaccharides (LPSs) have been reported to cause inflammation in the reproductive systems of several animals. This study aimed to elucidate the influence of LPS in the pathogenesis of CE in humans. We investigated whether LPS affected cytokine production and cell proliferation in the endometrium using in vivo and in vitro experiments. LPS concentrations were analyzed between control and CE patients using endometrial tissues. LPS administration stimulated the proliferation of EM-E6/E7 cells derived from human endometrial cells. High LPS concentrations were detected in CE patients. LPS concentration was found to correlate with IL-6 gene expression in the endometrium. Inflammation signaling evoked by LPS led to the onset of CE, since LPS stimulates inflammatory responses and cell cycles in the endometrium. We identified LPS and IL-6 as suitable candidate markers for the diagnosis of CE.

Progesterone-independent endometrial mRNA expression in dairy cows with clinical or subclinical endometritis.

Up to 50 % of dairy cows fail to resolve uterine involution and develop chronic clinical (CE) or subclinical endometritis (SE) 21 days after calving. Clinical endometritis is associated with purulent discharge, while SE is not associated with overt clinical signs. Along with numerous knowledge gaps related to its pathogenesis, SE does not allow for a straightforward and effective therapy. Therefore, it is crucial to unravel differences in the expression of genes among healthy, CE, and SE cows. This might contribute to the discovery of new drug candidates and, in consequence, a potentially effective treatment. In the present study, cows between 21 and 28 days postpartum (PP) were examined using vaginoscopy for the presence of vaginal discharge and endometrial cytology for the determination of the endometrial polymorphonuclear cell (PMN) percentage. Next, an endometrial biopsy sample was taken to investigate the expression of 13 selected candidate genes by qPCR. Uterine health status was assigned to healthy (absence of abnormal vaginal discharge and ≤5 % PMN, n = 13), SE (absence of abnormal vaginal discharge and >5 % PMN, n = 30), and CE (mucopurulent or purulent vaginal discharge and >5 % PMN, n = 9). At the same time, a blood sample was collected to assess serum progesterone concentration and to categorize cows as low (≤1 ng/mL) or high (>1 ng/mL) in progesterone. High expression of IL1B, IL6, IL17A, CXCL8, PTGES, PTGS1, PTGS2, and INHBA genes and low expression of FST was noted in the endometrium of CE compared to healthy cows. Increased endometrial INHBA expression was observed in both SE and CE compared to healthy cows. Interestingly, greater expression of PTGES and PRXL2B genes and lower expression of PTGS2 were characteristic of SE versus CE or healthy. Among cows with no overt clinical symptoms of uterine disease (healthy and SE), the endometrial expression of IL1 B, CXCL8, and PTGES was greater in cows with high versus low serum progesterone. Several genes were differentially expressed among healthy, SE, and CE cows indicating different pathways for the development of different uterine diseases. In conclusion, we found progesterone-independent SE markers, which suggests that low endometrial PTGS2 expression may be indicative of an inadequate immune response and thus contribute to the pathogenesis of SE.

Group A Streptococcal Endometritis and Toxic Shock causing Septic Pelvic Thrombophlebitis and Septic Pulmonary Emboli.

Group A Streptococcus (GAS) in the setting of postpartum endometritis can have severe and life-threatening complications. We report a rare case of septic pulmonary emboli that we surmised to have originated from septic pelvic thrombosis in the setting of GAS toxic shock syndrome (TSS) secondary to postpartum endometritis and intrauterine demise. Although the patient had source control with hysterectomy, she continued to have new septic emboli to the lungs seen on CT scans. CT scan of the pelvis demonstrated several filling defects in the renal and pelvic veins. The patient eventually responded well to anticoagulation in addition to antibiotics, which is similar to cases of Lemierre's syndrome. Additionally, we would like to bring attention to how important radiological findings can be missed if there is lack of interspecialty communication about the patient's clinical situation.

Hysteroscopic features suggestive of chronic endometritis: a systematic review.

The purpose of this systematic review is to identify common hysteroscopic findings suggestive of endometritis, chronic or subclinical, based on current scientific evidence. Data sources were MEDLINE, Embase, PubMed and other sources of grey literature. Four (4) authors independently selected studies addressing hysteroscopic detection of CE based on specific and clearly stated hysteroscopic criteria. The diagnosis was confirmed by histologic assessment, as stated in the materials and methods of these studies included. The initial search identified 599 studies, of which 21 met the inclusion criteria. Significant heterogeneity among published studies on Chronic endometritis (CE) remains the main limitation in performing a metanalysis and further analysis of diagnostic accuracy on the subject. Hysteroscopy is an important diagnostic tool in cases of chronic endometritis when accompanied by endometrial biopsies. Clinicians relate hyperaemia and endometrial oedema with chronic endometritis while more than half include micropolyposis as a pathognomonic feature of this subclinical condition. Micropolyps, stromal oedema, haemorrhagic spots, strawberry aspect, and hyperaemia are proposed as adequate indicators of hysteroscopic evidence of CE according to the literature. The impact of CE in long-term reproductive outcomes remain unclear, thus clinicians ought to communicate this to the patients and provide treatment where clinically appropriate. In addition, we present hysteroscopic images of histologically confirmed CE cases that could play the role of a hysteroscopic atlas.

Hysteroscopic versus histopathological agreement in the diagnosis of chronic endometritis: results from a retrospective observational study.

PURPOSE: To evaluate the agreement rate between hysteroscopy and pathological examination in case of chronic endometritis. METHODS: A retrospective observational study carried out at Gynecology and Obstetrics Department, Puerta de Hierro Hospital, Autónoma University of Madrid, Spain, from January 2021 to June 2022 was performed by obtaining data from 115 medical records of women who underwent office hysteroscopies that was compared with the findings of final histological examination of endometrial biopsy. Cohen's kappa index was used to evaluate this agreement rate. In addition, sensitivity, specificity, positive and negative predictive value and diagnostic accuracy were obtained. RESULTS: The agreement between hysteroscopic findings and histological examination showed a modest result with a Cohen's kappa index of 34%. In addition, we obtained a specificity of 70% and a sensitivity of 64%. The positive and negative predictive value were 60.8% and 73.4%, respectively. An excellent agreement rate (100%) between histological and hysteroscopic results was observed in presence of hyperemia and micropolyps. CONCLUSION: Although the sample size is not as large as that of other studies published so far, the first glance of our experience is that hysteroscopic signs are not yet sufficient to make an accurate diagnosis of chronic endometritis, thus requiring a histopathological confirmation to make it.

MicroRNAs in equine Endometritis: A review of pathophysiology and molecular insights for diagnostic and therapeutic strategies.

Endometritis plays an important role in mare infertility. Certain infectious agents interfere with the innate immune system of endometrium, causing a systemic inflammatory response that lasts for a long time and circulates via the blood or cellular degeneration, leading to endometritis due to bacterial endotoxins. Different small, non-coding RNA molecules are involved in many biological functions. For instance, microRNAs (miRNAs) are involved in the post-transcriptional regulation of gene expression. These miRNAs are important regulators of gene expression, primarily via inhibiting transcription and translation processes. This manuscript reviews: (1) pathomorphological findings in equine endometritis, (2) the expression and effects of eca-miR-17, eca-miR-223, eca-miR-200a, eca-miR-155, and eca-miR-205 in endometritis and (3) the therapeutic role of miRNA in equine endometritis. The miRNAs have a vital regulatory role in a wide range of inflammatory diseases by regulating the molecular mechanism of cytokines that cause inflammation through signal pathways. This review emphasizes the demand for cutting-edge genetic technologies and the development of novel pharmaceutical preparations to improve our understanding of the genes encoding by these miRNAs. It also focuses on the efficacy of miRNAs for control, early diagnosis, and prevention of endometritis.

Review: Postpartum reproductive disease and fertility in dairy cows.

This paper reviews recent data and concepts on metritis, purulent vaginal discharge (PVD), and endometritis in dairy cows and the ways in which these diseases affect reproductive performance. Metritis is characterized by fetid discharge from the uterus, with or without fever. Purulent vaginal discharge describes exudate that is >50% pus that may be attributable to uterine infection or cervicitis. Endometritis is inflammation of the uterus diagnosed by endometrial cytology with a proportion of neutrophils (typically ≥5%) that is associated with impaired fertility. Metritis and PVD are associated with uterine bacterial dysbiosis: changes in the microbiota to lesser diversity and greater abundance of pathogens, especially Gram-negative anaerobic bacteria, and Trueperella pyogenes in the case of PVD. Metritis is justifiably treated with approved antibiotics but criteria for more selective treatment without loss of performance are emerging. Purulent vaginal discharge is not synonymous with clinical endometritis, and greater precision in terminology is warranted. PVD is likely under-diagnosed and represents an opportunity for improved management in many herds. Endometritis seems in many cases to reflect persistent, dysregulated inflammation, for which the inciting cause is unclear. Postpartum uterine infection and inflammation have harmful effects on oocytes, embryo development, and the endometrium for at least three months, even if the disease is apparently resolved. Emerging concepts of the resolution and regulation of inflammation are promising for the improvement of prevention and therapy of endometritis.

Chronic endometritis: screening, treatment, and pregnancy outcomes in an academic fertility center.

PURPOSE: To identify the prevalence of chronic endometritis (CE), compare the efficacy of antibiotic regimens for CE, and examine pregnancy outcomes after treatment for CE among patients in an academic fertility clinic. METHODS: In this retrospective cohort study, data from patients who underwent endometrial sampling (ES) for CE evaluation at a single academic institution from 2014 to 2020 were collected and analyzed. Rates of CE were compared by indication for ES including recurrent pregnancy loss (RPL), implantation failure (IF), and recent first-trimester pregnancy loss. Treatment and pregnancy outcomes were also evaluated. RESULTS: Six hundred fifty-three individuals underwent ES to evaluate for CE. The overall prevalence of CE was 28.5%; when stratified by indication, the prevalence of CE was 66.2% for recent first-trimester loss, 27.9% for RPL, and 13.1% for IF (p < .001). Of those with CE, 91.9% received antibiotics, most commonly doxycycline (76.0%). CE clearance was not significantly different when doxycycline was compared to all other regimens (71.3% vs. 58.8%, p = .17), and 68.5% of patients cleared CE after one course of antibiotics. Following two antibiotic courses, CE was cleared in 88.3% of patients. Live birth rates (LBRs) were higher for those with cleared CE compared to patients with untreated CE (34.1% vs. 5.6%, p = .014) and similar for those with cleared CE versus those without CE (34.1% vs. 29.3%, p = .297). CONCLUSION: CE is common among patients with infertility, particularly those with a recent first-trimester loss. Treatment and clearance of CE were associated with higher LBRs; however, persistent CE was common despite treatment with antibiotics.

Local and systemic inflammatory response to the intrauterine infusion of enzymes during estrus in water buffaloes with subclinical endometritis.

Our objective was to determine the effects of intrauterine infusion of proteolytic enzymes in buffaloes with subclinical endometritis (SCE) at estrus on the resolution of endometrial inflammation and reproductive performance. Buffaloes at spontaneous estrus (E1) were screened for SCE by endometrial cytology to identify SCE (≥5% PMN, n = 22) and non-SCE (<5% PMNs, n = 14) animals. All buffaloes underwent uterine ultrasonographic examination, low volume uterine lavage (cytokines and acute phase proteins) and blood sampling (cytokines and acute-phase proteins) at E1. On the same day (E1), SCE buffaloes were randomly selected either for intrauterine infusion of proteolytic enzymes (ENY, n = 11) or saline (PC, n = 11). Buffaloes without SCE were kept as untreated control (NC; n = 14). All buffaloes were re-examined and re-sampled during subsequent estrus (E2), inseminated during the following estrus (E3), and assessed for fertility related outcomes. Proteolytic infusion resulted a reduction in uterine PMN (P < 0.01) in SCE buffaloes. The concentrations of interleukin (IL)-1ß and tumor necrosis factor (TNF)-α in uterus, and TNF-α and IL-10 in serum were higher (P < 0.01) at E1 in buffaloes with SCE (PC and ENY) compared to NC. After treatment, uterine IL-1ß and TNF-α (P = 0.02), and serum TNF-α and IL-10 were lower within the animals of ENY group (P < 0.01). Before treatment, buffaloes with SCE had higher concentrations (P < 0.01) of serum and uterine amyloid-A and haptoglobin, which decreased (P < 0.01) after treatment in the ENY group. None of the fertility outcomes differ between the treatment groups. In conclusion, intrauterine infusion of proteolytic enzymes reduced endometrial inflammation; however, did not improve reproductive outcomes.

Establishment and verification of hysteroscopic scoring system for chronic endometritis in infertile patients. / ä¸å­•æ‚£è€ æ ¢æ€§å­å®«å† è†œç‚Žå®«è ”é•œè¯„åˆ†ç³»ç»Ÿçš„æž„å»ºåŠéªŒè¯.

OBJECTIVES: To establish and verify a hysteroscopic scoring system for the diagnosis of chronic endometritis (CE) in infertile patients. METHODS: A total of 238 infertile patients who underwent hysteroscopy and endometrial biopsy in the Reproductive Medicine Center, Shijiazhuang Obstetrics and Gynecology Hospital Affiliated to Hebei Medical University from October 1 to December 31, 2019 were enrolled in the study. According to the results of CD138 immunohistochemistry, the patients were divided into CE group (n=73) and non-CE group (n=165). Univariate and binary logistic regression analyses were used to screen the risk factors of CE and a nomogram was establish for hysteroscopic scoring. Receiver operating characteristic (ROC) curve, calibration curve and Bootstrap resampling method were used to evaluate and verify the system. RESULTS: Univariate and binary logistic regression analyses showed that hyperemia area (HA) degree ≥2, micropolyps, polypoid hyperplasia of endometrium and history of ectopic pregnancy were independent risk factors for CE (all P<0.05). A nomogram was generated to establish a hysteroscopy scoring system based on the above four factors. The area under ROC curve of the hysteroscopy scoring system for predicting CE was 0.801 (95%CI:0.742-0.861), the sensitivity was 74.0% and the specificity was 73.9%. The calibration curve showed that the predicting value of the scoring system was highly consistent with the actual value. In the internal verification, the C-index was 0.7811. The predicting value of the verification group in the calibration curve was basically consistent with the actual value, indicating that the scoring system had good stability. CONCLUSIONS: The hysteroscopic scoring system composed of HA, micropolyp, polypoid hyperplasia of endometrium and history of ectopic pregnancy can effectively and intuitively predict CE, which is conducive to improving the diagnosis of CE.

A Comparative Proteomic Analysis to Explore the Influencing Factors on Endometritis Using LC-MS/MS.

The inflammatory system activated by uterine infection is associated with decreased fertility. Diseases can be detected in advance by identifying biomarkers of several uterine diseases. Escherichia coli is one of the most frequent bacteria that is involved in pathogenic processes in dairy goats. The purpose of this study was to investigate the effect of endotoxin on protein expression in goat endometrial epithelial cells. In this study, the LC-MS/MS approach was employed to investigate the proteome profile of goat endometrial epithelial cells. A total of 1180 proteins were identified in the goat Endometrial Epithelial Cells and LPS-treated goat Endometrial Epithelial Cell groups, of which, 313 differentially expressed proteins were accurately screened. The proteomic results were independently verified by WB, TEM and IF techniques, and the same conclusion was obtained. To conclude, this model is suitable for the further study of infertility caused by endometrial damage caused by endotoxin. These findings may provide useful information for the prevention and treatment of endometritis.

Differences in uterine and serum metabolome associated with metritis in dairy cows.

Objectives were to evaluate differences in the uterine and serum metabolomes associated with metritis in dairy cows. Vaginal discharge was evaluated using a Metricheck device (Simcro) at 5, 7, and 11 d in milk (DIM; herd 1) or 4, 6, 8, 10, and 12 DIM (herd 2). Cows with reddish or brownish, watery, and fetid discharge were diagnosed with metritis (n = 24). Cows with metritis were paired with herdmates without metritis (i.e., clear mucous vaginal discharge or clear lochia with ≤50% of pus) based on DIM and parity (n = 24). Day of metritis diagnosis was considered study d 0. All cows diagnosed with metritis received antimicrobial therapy. The metabolome of uterine lavage collected on d 0 and 5, and serum samples collected on d 0 were evaluated using untargeted gas chromatography time-of-flight mass spectrometry. Normalized data were subjected to multivariate canonical analysis of population using the MultBiplotR and MixOmics packages in R Studio. Univariate analyses including t-test, principal component analyses, partial least squares discriminant analyses, and pathway analyses were conducted using Metaboanalyst. The uterine metabolome differed between cows with and without metritis on d 0. Differences in the uterine metabolome associated with metritis on d 0 were related to the metabolism of butanoate, amino acids (i.e., glycine, serine, threonine, alanine, aspartate, and glutamate), glycolysis and gluconeogenesis, and the tricarboxylic acid cycle. No differences in the serum metabolome were observed between cows diagnosed with metritis and counterparts without metritis on d 0. Similarly, no differences in uterine metabolome were observed between cows with metritis and counterparts not diagnosed with metritis on d 5. These results indicate that the establishment of metritis in dairy cows is associated with local disturbances in amino acid, lipid, and carbohydrate metabolism in the uterus. The lack of differences in the uterine metabolome on d 5 indicates that processes implicated with the disease are reestablished by d 5 after diagnosis and treatment.

Results of in vitro fertilization after diagnosis and treatment of chronic endometritis.

OBJECTIVE: A significant cause of infertility is the inability of the embryo to implant. Endometritis is one of the major causes affecting embryo implantation. The present study addressed the diagnosis and effects of chronic endometritis (CE) treatment on pregnancy rates after in vitro fertilization (IVF). PATIENTS AND METHODS: We conducted this retrospective study on 578 infertile couples treated with IVF. In 446 couples, we performed a control hysteroscopy with biopsy before IVF. In addition, we examined the visual aspects of the hysteroscopy and the results of the endometrial biopsies, followed by antibiotic therapy if necessary. Finally, the results of IVF were compared. RESULTS: Of the 446 cases studied, we diagnosed 192 (43%) with chronic endometritis, either by direct observation or based on the histopathological result. In addition, the cases diagnosed with CE we treated with a combination of antibiotics. The group diagnosed at CE and subsequently treated with antibiotic therapy had a significantly higher pregnancy rate after IVF (43.2%) than the group without treatment (27.3%). CONCLUSIONS: Hysteroscopic examination of the uterine cavity was particularly important for the success of IVF. The initial CE diagnosis and treatment were an advantage for the cases in which we performed the IVF procedures.

The Impact of Chronic Endometritis on Infertility: Prevalence, Reproductive Outcomes, and the Role of Hysteroscopy as a Screening Tool.

OBJECTIVES: The objective of this study was to examine the prevalence of chronic endometritis (CE) in infertile women, its impact on reproductive outcomes, and the accuracy of hysteroscopy as a screening tool for CE. DESIGN: This was a prospective observational study. PARTICIPANTS: Participants involved in this study were 514 asymptomatic patients with infertility. SETTING: The review was conducted in a tertiary care center. METHODS: The participants underwent a hysteroscopy and endometrial biopsy (EMB). Antibiotics were given for cases of CE. We investigated the prevalence of CE in patients starting assisted reproductive technologies (ART) as a primary outcome. Secondary outcomes were the clinical pregnancy rate (CPR) in the ART cycle after hysteroscopy, EMB, and antibiotic treatment in cases of CE; the cumulative CPR in the subsequent 2 years after hysteroscopy and EMB; the sensitivity and specificity of hysteroscopy as a screening tool compared to EMB as the "gold standard" for diagnosing CE. RESULTS: CE was identified in 2.8% of patients starting ART (11/393). CPRs did not differ significantly between patients with CE and the entire cohort of patients without CE in the subsequent ART cycle (OR: 0.43; 95% CI: 0.09-2.02) or in the 2 years after EMB (OR: 0.56; 95% CI: 0.16-1.97). In a matched control comparison (with matching for age, basal FSH, and cause of infertility), CPR in patients with CE did not differ in the subsequent ART cycle (OR: 0.39; 95% CI: 0.09-1.61); however, their CPR in the 2 years after EMB was significantly lower (OR: 0.22; 95% CI: 0.13-0.38). The sensitivity and specificity of hysteroscopy as a screening tool for diagnosing CE were 8.3% and 90.1%, respectively. LIMITATIONS: Due to our cohort's low CE prevalence, we could not detect significant differences in CPRs. CONCLUSION: CE is rare in our studied population of asymptomatic patients starting ART. Hysteroscopy cannot replace EMB for diagnosing CE.

Xanthogranulomatous endometritis with unilateral salpingo-oophoritis in a postmenopausal woman masquerading as a malignancy.

Xanthogranulomatous endometritis (XGE) is a rare pathological entity which is characterised by sheets of foamy histiocytes and lymphoplasmacytic infiltrates. This condition can mimic endometrial carcinoma. We report a case, clinically suspected as carcinoma of the endometrium/ovary, which was diagnosed as XGE with left salpingo-oophoritis on histopathology.

Comparison of PCR-HRM, colorimetric LAMP and culture based diagnostic assays in the detection of endometritis caused by Streptococcus equi subsp. zooepidemicus in mares.

Streptococcus equi subsp. zooepidemicus (S. zooepidemicus) is one of the causative agents of equine endometritis. In this study, a panel of different bacterial species, and colonies derived from bacteriological cultures of 38 clinical samples, were subjected to Loop-Mediated Isothermal Amplification (LAMP) assay and PCR, followed by high-resolution melt (HRM) curve analysis. All clinical samples were genotyped into three distinct groups based on HRM curve analysis. Differences in melting curve profiles were a reflection of DNA variation in sorD gene which was confirmed by DNA sequencing. A mathematical model based on Genetic Confidence Percentage (GCP) was used in HRM curve analysis and a cut-off point value was established which differentiated S. zooepidemicus isolates without requiring visual interpretation of curve profiles. The accuracy of PCR-HRM and bacterial culture in detection of S. zooepidemicus were identical with 100% sensitivity and specificity, while LAMP assay had similar specificity but a lower sensitivity (89.5%). PCR-HRM and LAMP assay provided an effective detection method with a turn-around time of six hours for PCR-HRM and 120 min for LAMP assay, compared to a minimum three days that was required when routine bacteriological culture method was used. In summary, results indicate that LAMP had the quickest turnaround, and HRM curve analysis could potentially be used for genotyping without DNA sequencing. Any mare suspected of endometritis will benefit from developed rapid diagnostic tests for detection of S. zooepidemicus and proper treatment prior to being bred and will mitigate unnecessary treatment and antibiotic resistance.

Effect of different antibiotic therapies on the reproductive outcomes of fresh embryo transfer for chronic endometritis: A retrospective cohort study.

OBJECTIVE: To investigate the reproductive outcomes by comparing two kinds of antibiotic schemes for chronic endometritis (CE) in infertile women's fresh embryo transfer (FET) cycles and identify subgroups of patients with CE who need long-term antibiotics treatment. DESIGN: A retrospective cohort study. SETTING: University-based reproductive medical center. PATIENT(S): A total of 492 women with CD138-positive plasmacytes per 10 high-power fields (CD138+/10HPF). INTERVENTION(S): Hysteroscopy was performed and endometrial biopsy samples were collected in the proliferative phase. Long-term or short-term antibiotics were administrated. After antibiotics treatment, patients underwent in vitro fertilization (IVF)/ intracytoplasmic sperm injection (ICSI) and received ET. MAIN OUTCOME MEASURE(S): Ongoing pregnancy rate, clinical pregnancy rate, clinical miscarriage rate. RESULT (S): There were no significant differences in pregnancy outcomes between patients with CD138+/10HPF 1-4 (low-grade CE) who received long-term antibiotic therapy and short-term antibiotics groups. Among women with CD138+/10HPF ≥5 (high-grade CE), live birth rate (48.4% vs. 14.7%, p = .001), clinical pregnancy rate (66.7% vs. 35.3%, p = .002) and ongoing pregnancy rate (59.1% vs. 20.6%, p < .001) in the long-term arm were significantly higher than that in the short-term arm. The clinical miscarriage rate (21.0% vs. 58.3%, p = .013) was statistically lower in the long-term antibiotics group, but no statistical differences were found between the two groups in preterm delivery rate. CONCLUSION: Long-term antibiotics treatment was a sensible choice to improve pregnancy outcomes in women with CD138+/10HPF ≥5 (high-grade CE). The pregnancy outcomes of women with low-grade CE only defined by histological diagnosis were not greatly improved after antibiotic therapy. Therefore, we recommended the proper diagnosis criteria were CD138+/10HPF ≥5 pathologically.

Chronic endometritis - is it time to clarify diagnostic criteria?

Chronic endometritis is a persistent, low-intensity inflammation of endometrial mucosa, characterized by the infiltration of plasma cells into the endometrial stroma This immunological alteration is thought to be a consequence of a bacterial infection. For a long time, chronic endometritis was poorly investigated and rarely considered in clinical practice because it is either asymptomatic or presents with no specific symptoms. Its association with adverse effects on fertility and retrospectively reported effectiveness of antibiotic treatment were the main reasons for a growing interest in this endometrial pathology. Chronic endometritis is now a hot topic in recurrent pregnancy loss and recurrent implantation failure research. Nevertheless, there are still no recommendations to include chronic endometritis investigation in a clinical evaluation of infertile patients. The uncertain role of this condition is an effect of significant differences in study results presented by different research groups. One important reason for these inconsistent findings is a lack of standardised chronic endometritis diagnostic methods. We present a review of the literature, focusing on the currently available chronic endometritis diagnostic techniques. The review is subdivided into three parts concerning the diagnostic accuracy of three main diagnostic modalities. Histopathological examination of endometrial tissue, hysteroscopic evaluation of uterine cavity and identification of the bacterial factor. In conclusion, it is of great importance to establish a consensus on the diagnostic criteria for chronic endometritis. This is the only way to enhance international cooperation and create well-design multicenter studies to evidence the role of this endometrial pathology in infertility.

Should we stop screening for chronic endometritis?

Chronic endometritis is a poorly understood infectious or inflammatory process, potentially disrupting the correct implantation of a human embryo (Puente et al., 2020). The exact prevalence is a subject of discussion and ranges across the available literature from 2% to almost 60%, with a higher suspicion of the condition being present in women with recurrent early pregnancy loss and recurrent implantation failure (Puente et al., 2020). The impact of chronic endometritis on reproductive outcomes following IVF remains questionable given the lack of proper data convincingly showing an improvement after diagnosis and treatment. This article aims to provide the reader with a critical appraisal of current diagnostic methods, treatments and patient populations to be tested for chronic endometritis.

Significance of multiple myeloma oncogene 1 immunohistochemistry in chronic endometritis detection in patients with recurrent pregnancy losses: an observational study.

The most reliable chronic endometritis diagnosis is based on immunohistochemistry plasma cell identification in endometrial samples. Our study aimed to compare multiple myeloma oncogene 1 (MUM1) and syndecan-1/CD138 immunohistochemistry staining for chronic endometritis diagnosis among patients with recurrent pregnancy loss. We evaluated the presence of endometrial stromal changes. Fifty-four patients with a history of at least two intrauterine pregnancy losses underwent diagnostic hysteroscopy in the follicular phase of the cycle with endometrial aspiration biopsy. In all 54 cases, three successive sections were cut from each paraffin-embedded tissue block for hematoxylin and eosin (H&E), CD138 and MUM1 staining. The goal was to evaluate the level of agreement between the MUM1 and CD138 results and plasma cell detection rate in assessing the endometrial stromal changes. The concordance analysis between CD138 and MUM1 immunohistochemistry staining showed consistent results in 43 of 54 (79.6%) cases. The level of agreement was moderate, based on a Kappa value of 0.60. MUM1 immunostaining was positive for CE in more cases than CD138 staining, and this difference was statistically significant, showing a higher sensitivity of MUM1 in plasma cell detection (p=0.01). Endometrial stromal changes were observed in the majority of cases - 49/54 (90%). Samples without stromal changes were consistently negative for plasma cells using both CD138 and MUM1 staining. We demonstrated that MUM1 staining, used in conjunction with assessing endometrial stromal changes, contributes to a more accurate and comprehensive diagnosis of chronic endometritis.