Decreased levels of peritoneal interleukin-1 receptor antagonist in patients with endometriosis and disease-related dysmenorrhea

DIA-based analysis of the menstrual blood proteome identifies association between CXCL5 and IL1RN and endometriosis

Endometriosis is a gynecological disease related to menstruation that affects nearly 10% of reproductive-age women. However, so far, there are no reliable diagnostic biomarkers for endometriosis, causing a delay in diagnosis of 6.7 ± 6.2 years. Menstrual blood is a non-invasive source of endometrial tissue that can be analyzed for biomarkers of endometriosis. In this study, menstrual blood samples were collected from women with (n = 8) and without (n = 8) endometriosis. Data Independent Acquisition (DIA)-based mass spectrometry and bioinformatic analysis were used to quantify and identify differentially expressed proteins (DEPs) using the thresholds of fold change >1.5 and P value <0.05. A total of 95 DEPs were identified in menstrual blood from women with endometriosis compared to women without endometriosis, of which 64 were up-regulated and 31 were down-regulated. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were used to functionally annotate DEPs. Protein-protein interaction (PPI) network analysis was then conducted to identify hub genes and the MCODE plugin placed CXCL1, CXCL3, CXCL5, CCL18, and IL1RN in the most significant cluster network. The expression of the above candidate proteins was confirmed by enzyme-linked immunosorbent assay (ELISA), among which CXCL5 and IL1RN protein expression was increased in patients with endometriosis, indicating that CXCL5 and IL1RN in menstrual blood may be useful biomarkers to diagnose endometriosis from non-invasive samples. SIGNIFICANCE: Endometriosis is a common gynecological disease that causes discomfort in many women. Unfortunately, the diagnosis of endometriosis is frequently delayed due to a lack of reliable non-invasive biomarkers. To our knowledge, this is the first time that DIA-MS was used to characterize the proteome and identify the differentially expressed proteins in menstrual blood from women with endometriosis. The results, as confirmed by ELISA, showed that CXCL5 and IL1RN protein expression is significantly increased in patients with endometriosis, indicating that these proteins can be used as biomarkers for endometriosis. This study contributes to the identification of putative endometriosis biomarkers from non-invasive samples and lays the groundwork for future research into the roles of CXCL5 and IL1RN in the pathogenesis of endometriosis.

Non-invasive diagnosis of endometriosis: Immunologic and genetic markers

Endometriosis, a benign gynecologic and chronic inflammatory disease, is defined by the presence of endometrial tissue outside the uterus characterized mainly by pelvic pain and infertility. Because endometriosis affects approximately 10% of females, it represents a significant socioeconomic burden worldwide having tremendous impact on daily quality of life. Accurate and prompt diagnosis is crucial for the management of this debilitating disorder. Unfortunately, diagnosis is typically delayed to lack of specific symptoms and readily accessible biomarkers. Although histopathologic examination remains the current gold standard, this approach is highly invasive and not applicable for early screening. Recent work has focused on the identification of reliable biomarkers including immunologic, ie, immune cells, antibodies and cytokines, as well as genetic and biochemical markers, ie, microRNAs, lncRNAs, circulating and mitochondrial nucleic acids, along with some hormones, glycoproteins and signaling molecules. Confirmatory research studies are, however, needed to more fully establish these markers in the diagnosis, progression and staging of these endometrial lesions.

Protective effects of chicoric acid on LPS-induced endometritis in mice via inhibiting ferroptosis by Nrf2/HO-1 signal axis

Chicoric acid (CA), a natural phenolic acid extracted from Mediterranean vegetable chicory, has anti-oxidative effect. We aimed to investigate the effects of CA on endometritis and clarify the underlying mechanism. C57BL/6 mice were divided into five groups: control group, LPS group, and LPS + CA groups. All mice except control group were infused of LPS into the uterus. The mice of LPS + CA groups were intraperitoneally injected CA 1 h before LPS challenge. CA significantly alleviatedLPS-induced pathological damage, MPO activity, and inflammatory cytokine production. CA significantly suppressed ferroptosis in LPS-induced endometritis. CA also attenuated LPS-induced NF-κB activation. Furthermore, Nrf2 and HO-1 expression were increased by CA. Moreover, the inhibition of CA on LPS-induced endometritis and ferroptosis were markedly prevented in Nrf2 knockdown mice. In conclusion, the results suggested CA protected mice against LPS-induced endometritisthrough inhibiting ferroptosis via Nrf2/HO-1 signaling pathway.

Cytokine and growth factor profile in endometriosis: a multiplex analysis of peritoneal fluid to assess diagnostic utility

We aimed to assay cytokines and growth factors in peritoneal fluid samples from women with and without endometriosis to understand the inflammatory milieu, and assess their potential diagnostic utility. This cross-sectional study conducted at a tertiary care hospital included 54 women, aged 20-45 years, with regular menstrual history and undergoing diagnostic/therapeutic laparoscopy for infertility and/or pain. Peritoneal fluid samples were collected after insertion of trocar & laparoscope but prior to other surgical intervention. A multiplex immunoassay of 27 cytokines and growth factors was performed. The concentration of FGF2 and CSF3 were significantly lower in women with endometriosis than without endometriosis (p = .043 and .003, respectively). The levels of CCL2 and IL1RN were significantly higher in moderate-severe than in minimal-mild endometriosis (p = .038 and .043, respectively). Phase-specific comparison revealed that in proliferative phase, the levels of CSF2 and CSF3 were lower in women with endometriosis than without the disease (p = .047 and .013, respectively). The ROC curve analysis provided a cutoff value 0.78 and 0.76 for FGF2 and CSF3, respectively. Cytokines and growth factors such as FGF2, CSF3, CSF2, CCL2 and IL1RN seem to contribute to the pathogenesis of endometriosis and may have a potential utility for the diagnosis of endometriosis.

Anti-inflammatory cytokines in endometriosis

Although the pathogenesis of endometriosis is not fully understood, it is often considered to be an inflammatory disease. An increasing number of studies suggest that differential expression of anti-inflammatory cytokines (e.g., interleukin-4 and -10, and transforming growth factor-β1) occurs in women with endometriosis, including in serum, peritoneal fluid and ectopic lesions. These anti-inflammatory cytokines also have indispensable roles in the progression of endometriosis, including by promoting survival, growth, invasion, differentiation, angiogenesis, and immune escape of the endometriotic lesions. In this review, we provide an overview of the expression, origin, function and regulation of anti-inflammatory cytokines in endometriosis, with brief discussion and perspectives on their future clinical implications in the diagnosis and therapy of the disease.

Genetic Variation at Chromosome 2q13 and Its Potential Influence on Endometriosis Susceptibility Through Effects on the IL-1 Family

Endometriosis is characterized by the growth of epithelial and stromal cells outside the uterine cavity. It has a complex etiology and affects ∼10% of reproductive age women. It is accompanied by a chronic inflammatory response with substantial evidence to indicate genetic susceptibility. The causal genes and their pathways leading to endometriosis, however, are still unknown. Recently, genomewide association studies on endometriosis identified 14 genomic risk loci in women of European and Japanese ancestry. It is becoming increasingly clear that these risk regions are intergenic and thus contribute to disease susceptibility through regulatory mechanisms, most likely mediated through regulation of genes within a restricted distance from the risk variants. One endometriosis risk locus has been detected at chromosome 2q13 within an inflammatory-rich region of gene transcripts and thus may play a role in the inflammation component of the disease. We carried out detailed analysis of the genomic region 250 kb on either side of sentinel SNP rs10167914 and identified 21 transcripts which contained 6 interleukin (IL)-1 family genes, 3 previously reported coding genes that have a relationship to inflammation, 4 novel coding, or pseudogenes, and 8 noncoding RNA transcripts. Through an extensive literature search, we examined the roles these genes and their resultant proteins play in endometriosis pathogenesis. The results suggest alteration in the expression the IL-1 family transcripts either alone or as a complex milieu could have a significant influence on endometriosis and should be prioritized for future study on the implications of inflammation on endometriotic lesions.

Surgical removal of endometriotic lesions alters local and systemic proinflammatory cytokines in endometriosis patients

OBJECTIVE

To determine the impact of endometriotic lesion removal on local and systemic inflammation.

DESIGN

Multiplex cytokine analysis on samples from endometriosis patients before surgery, 2 weeks after surgery, and 3 months after surgery.

SETTING

Academic teaching hospital and university.

PATIENT(S)

A total of 43 endometriosis patients before and after excision of lesions by means of laparoscopic surgery, and 25 normal women.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Plasma, eutopic and ectopic tissue, and peritoneal fluid cytokine levels.

RESULT(S)

Compared with presurgery plasma samples, levels of granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin (IL) 2, IL-8, and IL-10 decreased significantly by 2 weeks after surgery in endometriosis patients. Interestingly, levels began to rise at 3 months after surgery in most cases. In tissue, levels of GM-CSF and IL-15 were lower in eutopic tissue, while levels of basic fibroblast growth factor, interferon-inducible protein 10, IL-1 receptor antagonist, granulocyte colony-stimulating factor, macrophage inflammatory protein 1β, IL-7, and IL-5 were higher in eutopic than in ectopic tissue. In peritoneal fluid, levels of IL-5 and IL-12 were higher in early versus advanced stages of endometriosis. Compared with normal women, plasma from endometriosis patients had higher levels of inflammatory cytokines.

CONCLUSION(S)

Endometriotic lesion removal significantly alters the inflammatory profile both locally and systemically in women with endometriosis. Our findings indicate that ectopic lesions are the major drivers of systemic inflammation in endometriosis. The transitory nature of the change may reflect the recurrence of the condition and the influence of systemic factors in its onset.

Serum anti-inflammatory cytokines for the evaluation of inflammatory status in endometriosis

Background:

Endometriosis is a frequent gynecologic disease with a severe impact on the quality of life in the affected women; its pathogenesis is yet to be fully understood, with an altered immunity as a possible key factor. The present study aimed to investigate the serum anti-inflammatory cytokine profile in the patients with endometriosis compared with the healthy controls.

Materials and Methods:

One hundred and sixty women were included, divided into two study groups (Group I — endometriosis; Group 2 — healthy women). We evaluated the serum levels of interleukin-1 receptor antagonist (IL-1Ra), IL-2, IL-2R, IL-4, IL-10, IL-13, and IL-15 with the use of Human multiplex cytokine panels. Statistical analyses (normality distribution analysis, independent t-test, Mann–Whitney U-test) were performed using IBM SPSS software (version 22.0) and GraphPad Prism (version 5.00); receiver operating characteristic curve were used to demonstrate the diagnostic performance of the studied markers.

Results:

The mean serum level of IL-1Ra, IL-4, and IL-10 were significantly higher in women with endometriosis compared to women free of disease from the control group (30.155, 138.459, and 1.489, respectively, compared to 14.109, 84.710, and 0.688, respectively; P < 0.001, P < 0.001, and P = 0.002, respectively.). No significant differences in the mean serum levels of IL-2, IL-13, and IL-15 were observed between the studied groups and IL-2R had a very low detection rate.

Conclusion:

Endometriosis is associated with elevated levels of anti-inflammatory cytokines, IL-1Ra, IL-4, and IL-10, markers that have a potential role as a prognostic factor for endometriosis.

IL-1β increases expression of tryptophan 2,3-dioxygenase and stimulates tryptophan catabolism in endometrioma stromal cells

PROBLEM

Immune tolerance to endometriotic cells is important to promote endometriosis. Tryptophan 2,3-dioxygenase (TDO) enhances immune tolerance by catabolizing tryptophan to kynurenine. We studied whether interleukin-1β (IL-1β), a typical endometriosis-associated cytokine, affects the expression of TDO and the catabolism of tryptophan in endometrioma stromal cells (ESCs). We also studied whether the expression of TDO is involved in IL-1β-induced secretion of IL-6 and IL-8 in ESCs.

METHOD OF STUDY

Nineteen endometriotic patients of reproductive age with normal menstrual cycles were recruited. Primary cultures of ESCs were treated with IL-1β and TDO siRNA. TDO mRNA was measured using quantitative PCR. TDO protein was measured using Western blotting. Concentrations of kynurenine in condition media were measured using Ehrlich reagent. Concentrations of tryptophan in conditioned media were measured using tryptophan detection kit. Concentrations of IL-6 and IL-8 in conditioned media were measured using ELISA kits.

RESULTS

IL-1β (1 ng/mL) increased the expression of TDO mRNA and TDO protein in ESCs. IL-1β-treated ESCs increased the production of kynurenine and the effect was inhibited by TDO siRNA. Treatment with the siRNA also decreased IL-1β-induced secretion of IL-6 and IL-8 from ESCs.

CONCLUSION

IL-1β is suggested to stimulate tryptophan catabolism and production of IL-6 and IL-8 by increasing TDO expression in endometriosis.

The association between endometriosis and polymorphisms in the interleukin-1 family genes in Korean women

PROBLEM

To investigate the association between polymorphisms of the interleukin-1 (IL-1) family genes and endometriosis in Korean women.

METHOD OF STUDY

In this case-control study, the IL-1α -889C>T, IL-1 receptor antagonist (IL-1RA) 86-bp microsatellite, IL-1 receptor 1 (IL-1R1) 52C>A, 294C>T, 1498T>C, 1632A>G, IL-1R2 rs2072472 C>T and rs7561460 C>T polymorphisms were analyzed in women with (n = 138) and without (n = 214) endometriosis using restriction fragment length polymorphism (RFLP) analysis, TaqMan assay, or DNA sequencing. Serum IL-1α, soluble IL-1RA (sIL-1RA), and sIL-1R2 levels were measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Among the polymorphisms measured, the 1498T>C polymorphisms in the IL-1R1 gene were found to be related with early-stage endometriosis but not with advanced-stage endometriosis. The genotypes with at least one T allele (CT + TT) were less frequently observed in early-stage endometriosis compared with normal controls (OR = 0.44, 95% CI = 0.22-0.87, P = 0.02). Serum sIL-1R2 levels were significantly lower (P < 0.01) in women with endometriosis than in normal controls, whereas no difference in serum sIL-1RA levels between these two groups was noted. The single and haplotype genotypes of the IL-1R2 and IL-1RA microsatellite polymorphisms were not related with these serum levels.

CONCLUSION

The IL-1R1 1498T>C polymorphism is associated with early-stage endometriosis in Korean women.

Expression of interleukin-1 (IL-1) ligands system in the most common endometriosis-associated ovarian cancer subtypes

OBJECTIVES

Endometrioid carcinoma of the ovary is one of the most types of epithelial ovarian cancer associated to endometrioisis. Endometrioid tumors as well as endometriotic implants are characterized by the presence of epithelial cells, stromal cells, or a combination of booth, that resemble the endometrial cells, suggesting a possible endometrial origin of these tumors. Pro-inflammatory cytokines, including interleukin-1 (IL-1) have been reported to be involved in both endometriosis and ovarian carcinogenesis. The major objective of this study was to determine the level expression of IL-1 ligands system (IL-1alpha, IL-1beta and IL-1RA) in the most common subtypes of ovarian cancer cells compared to endometrial cells.

METHODS

We used primary endometrial cells, endometrial cell line RL-952 and different subtypes of epithelial ovarian cancer cell lines including TOV-112D (endometrioid), TOV-21G (clear cell) and OV-90 (serous). Immunofluorescence and real-time PCR analysis were used respectively for detecting IL-1 ligands at the levels of cell-associated protein and mRNA. Soluble IL-1 ligands were analyzed by ELISA.

RESULTS

We demonstrated that IL-1 ligands were expressed by all endometriosis-associated ovarian cancer subtypes and endometrial cells. In contrast to other cancer ovarian cells, endometrioid cells exhibit a specific decrease of cell-associated IL-1RA expression and its soluble secretion.

CONCLUSION

Endometrioid ovarian cancer exhibits an alteration in the expression of IL-1RA, a key protector against tumorogenic effects of IL-1. This alteration evokes the same alteration observed in endometriotic cells in previous studies. This suggests a possible link between the endometrium, the tissue ectopic endometriosis and endometrioid ovarian cancer.

Change of proinflammatory cytokines follows certain patterns after induction of endometriosis in a mouse model

OBJECTIVE

To examine the change in proinflammatory cytokines in the pathologic processes of endometriosis in mice.

DESIGN

A dynamic study on a murine model of endometriosis.

SETTING

Medical school.

ANIMAL(S)

Female BALB/c mice.

INTERVENTION(S)

Endometriosis was induced by injecting endometrial fragments of syngenic mice into the peritoneal cavity of model mice; in control group, phosphate-buffered saline instead of fragments was injected. The peritoneal fluid and the endometriotic lesions were harvested 1 to 21 days after the induction.

MAIN OUTCOME MEASURE(S)

The endometriotic lesions were weighed, the gene and protein levels of some proinflammatory cytokines, including interleukin 1beta, tumor necrosis factor alpha, vascular endothelial growth factor, and monocyte chemoattractant protein 1, were determined by real-time quantitative polymerase chain reaction and enzyme-linked immunosorbent assay, respectively.

RESULT(S)

The levels of these cytokines reached the first peak on the first day and no endometriotic lesions were found. The lesions began to appear on the second day, presenting red color during the initial 6 days, and then they turned dark-red, brown, or bluish. The adhesion took place on the 9th day, and all the lesions evolved into white or transparent cysts on the 15th day. Corresponding to these changes, the second and the third peaks were identified during the 3rd-6th day and the 12th-15th day, respectively.

CONCLUSION(S)

The change pattern of cytokines over time might bear some relationship with the development and progression of the endometriosis.

Dysmenorrhea: risk factors in women with endometriosis

Although it is generally accepted that endometriosis is responsible for dysmenorrhea, as well as other symptoms such as infertility, the precise relationship between the severity of dysmenorrhea and various characteristics of disease, such as stage and the type or site of endometriotic lesions, has been elusive and often a matter of heated debate, owing largely to conflicting reports. Here we review factors that are reported to be associated with dysmenorrhea in endometriosis. We also demonstrate, through a real example, that different statistical models employed in data analyses may yield somewhat different sets of risk factors, and the difference may not be always resolved within the same data set. In addition, we make the point that despite the best-fitting models, there may still be a sizable portion of variation in the severity of dysmenorrhea that can not be explained completely by the identified risk factors, suggesting that factors other than those of surgical findings or patient characteristics may also be responsible for dysmenorrhea severity. We review some possible factors that may also be responsible for the risk and severity of dysmenorrhea. Finally, we expose areas in need of further research.