Interleukin-6: another piece of the endometriosis-cytokine puzzle

Effects of bone marrow mesenchymal stem cell transplantation on tumor necrosis factor-alpha receptor 1 expression, granulosa cell apoptosis, and folliculogenesis repair in endometriosis mouse models

BACKGROUND AND AIM

Endometriosis affects the ovaries and causes a decrease in the oocyte quality during endometrial receptivity. During the development of ovarian follicles, paracrine communication occurs between granulosa cells and oocytes. This study was conducted to determine the effects of bone marrow mesenchymal stem cell transplantation on tumor necrosis factor-alpha (TNF-α) receptor 1 (TNFR1) expression, granulosa cell apoptosis, and folliculogenesis in endometriosis mouse models.

MATERIALS AND METHODS

This study involved 42 female mice, which were divided into three groups: Healthy mice (T0), endometriosis mice without transplantation (T1), and endometriosis mice with bone marrow mesenchymal stem cell transplantation (T2). The mice were injected intraperitoneally with endometrial fragments (200 μL) to become endometriosis models. On day 15, the endometriosis models received mesenchymal stem cells. Sample collection was performed on day 29. Granulosa cell apoptosis and TNFR1 expression were examined using immunohistochemical staining, and folliculogenesis was assessed using hematoxylin and eosin staining of ovary samples. The data obtained from both examinations were statistically analyzed using Statistical Package for the Social Sciences.

RESULTS

The results showed that TNFR1 expression is significantly decreased in T2 (p<0.004). The apoptosis of granulosa cells was lower in T2 (p<0.000). The primary, secondary, and graafian follicle counts in T2 were significantly increased.

CONCLUSION

Bone marrow mesenchymal stem cell transplantation in endometriosis mouse models can reduce TNFR1 expression and granulosa cell apoptosis and improve folliculogenesis.

MicroRNAs in endometriosis: biological function and emerging biomarker candidates†

MicroRNAs (miRNAs), a class of small noncoding RNA molecules, have been recognized as key post-transcriptional regulators associated with a multitude of human diseases. Global expression profiling studies have uncovered hundreds of miRNAs that are dysregulated in several diseases, and yielded many candidate biomarkers. This review will focus on miRNAs in endometriosis, a common chronic disease affecting nearly 10% of reproductive-aged women, which can cause pelvic pain, infertility, and a myriad of other symptoms. Endometriosis has delayed time to diagnosis when compared to other chronic diseases, as there is no current accurate, easily accessible, and noninvasive tool for diagnosis. Specific miRNAs have been identified as potential biomarkers for this disease in multiple studies. These and other miRNAs have been linked to target genes and functional pathways in disease-specific pathophysiology. Highlighting investigations into the roles of tissue and circulating miRNAs in endometriosis, published through June 2018, this review summarizes new connections between miRNA expression and the pathophysiology of endometriosis, including impacts on fertility. Future applications of miRNA biomarkers for precision medicine in diagnosing and managing endometriosis treatment are also discussed.

Sphingosine 1 Phosphate (S1P) Increased IL-6 Expression and Cell Growth in Endometriotic Cells

OBJECTS

There is growing evidence that sphingosine 1-phosphate (S1P) is involved in inflammatory diseases. As endometriosis is known as an inflammatory disease, we investigated the role of S1P system in the development of endometriosis.

METHODS

The expression of sphingosine kinase (SphK) 1 in endometriosis lesions was examined by immunohistochemistry. The cystic fluid of ovarian cysts/tumors were obtained to measure S1P concentrations. Endometriotic stromal cells (ESC) derived from endometrioma were used for in vitro experiments.

RESULTS

Sphingosine kinase 1 was detected in epithelium and stromal cells of endometriotic lesions. The mean S1P concentration in the cystic fluid of endometriomas was higher than that in nonendometriomas significantly (98.2 nM vs less than 1.5 nM, P < .01). Interleukin-1β (IL-1β) or transforming growth factor-β exhibited 2.7-fold and 11.5-fold increase in SphK1 messenger RNA (mRNA) expression in ESC, respectively (P < .01). Higher dose of S1P (125nM) increased the cell number of ESC by 20%, and low dose of S1P (1.25 nM and 12.5 nM) induced IL-6 mRNA production and IL-6 secretion by ESC dose-dependently. JTE013, an antagonist for S1PR2, partially suppressed IL-6 induction by S1P (P < .05). JTE013 and VPC23019, an antagonist for S1PR1 and S1PR3, suppressed the ESC proliferation induced by S1P.

CONCLUSION

The present study for the first time proved that the SphK-S1P-S1PR axis play a role of accelerating inflammation and growth of endometriotic cells.

Local and systemic levels of cytokines and danger signals in endometriosis-affected women

Endometriosis is a prevalent gynaecological disorder with a still unclear pathogenesis. So far inflammatory mechanisms are associated with disease progression and critical reviews have discussed the so-called 'danger theory' related to endometriosis. Hence, we performed immunoassays to evaluate whether local inflammation is linked to the severity of the disease. In addition, we investigated the role of recently described cytokines IL-33, IL-32α and the 'alarmin' high mobility group box 1 (HMGB1). We confirmed a dysfunctional immune response in the local environment of women suffering from endometriosis. However, we found no direct evidence for a significant up-regulation of danger signals in endometriosis, irrespective of the severity of the disease.

A 10-Year Study of Endometriosis in an Indigenous Black African Population

Background

Endometriosis is a debilitating disease in women of child-bearing age.

Objective

To describe the pattern of presentation, stage of endometriosis and biophysical profile of patients with endometriosis.

Method

A retrospective study of 61 consecutive infertile patients between June 2003 and November 2014.

Results

The means (±SD) of age (years) and of body mass index (BMI) (kg/m2) of the patients were 34.1 (4.3) and 25.8 (5.0), respectively. A relatively high percentage (43, 70.5%) of the women were in the age range of 31-40 years; had normal BMI (27, 44.3%); were nulliparous (53, 86.9%) and were of primary infertility (40, 65.6%). The mean (±SD) age at menarche, of cycle length, of the duration of flow and of years trying to conceive were 12.9 (1.7) years, 29.1 (2.7) days, 4.7 (1.1) days and 5.2 (3.8) years, respectively. A high proportion of them (37, 60.7%) presented with severe endometriosis. The main symptoms at presentation was dysmenorrhea (47, 73.8%). Of the 32 (52.5%) with associated utero-tubal factor, 20 (62.5%) were in severe stage of endometriosis. Among women with endometriosis, those with primary infertility were over three times more likely to present with menorrhagia than those with secondary infertility (χ² = 4.70; p value = 0.03; OR = 3.33; 95% CI = 1.10, 10.12). Only 3 (4.9%) had diagnosis of endometriosis in first-degree relative. Dysmenorrhea was a strong predictor of severe endometriosis.

Conclusions

There may be some trends in the biophysical profile of infertile women with endometriosis which may influence diagnosis and management.

Endometrial CXCL13 expression is cycle regulated in humans and aberrantly expressed in humans and Rhesus macaques with endometriosis

C-X-C ligand 13 (CXCL13), a regulator of mucosal immunity, is secreted by human endometrial epithelium and may be involved in embryo implantation. However, cyclic expression of human endometrial CXCL13 in health and disease is not well studied. This study examines cycle stage-specific endometrial CXCL13 expression in normal humans when compared to those with biopsy-confirmed, stage 1 to 4 endometriosis using real-time reverse transcriptase, real-time polymerase chain reaction and immunohistochemistry. Eutopic endometrial CXCL13 expression was also compared between normal, control Rhesus macaques, and macaques with advanced endometriosis. In healthy women, CXLC13 messenger RNA expression was minimal in the proliferative phase and maximal in the secretory phase. However, in the presence of endometriosis, proliferative-phase endometrial expression markedly increased in both humans and rhesus subjects (P < .05). The cross-species and cross-stage concordance suggests a pathophysiologic role for CXCL13 in endometriosis and its use as a biomarker for disease.

Serum level of IL-10 is increased in patients with endometriosis, and IL-10 promotes the growth of lesions in a murine model

Immune dysregulation may be involved in the development of endometriosis. The anti-inflammatory cytokine IL-10 plays an important role in eliminating unwanted cells and cellular debris in a silent way. We investigated the modulatory role of IL-10 in the development of endometriosis. We observed that the serum level of IL-10 in patients with endometriosis was significantly higher than that in healthy subjects or in control subjects with other gynecological disease. Monocyte-derived dendritic cells acquired from male donors and subsequently conditioned with serum from women with endometriosis exhibited a tolerogenic phenotype, including increased IL-10 production, lower IL-12 secretion, and down-regulation of CD86 and HLA-DR molecules. Depletion of IL-10 activity in a C57BL/6 mouse model of surgically induced endometriosis significantly decreased the size of endometrial lesions. In contrast, IL-10 administration promoted the growth of endometrial lesions in this model. In addition, infiltrated plasmacytoid dendritic cells were the primary IL-10-secreting immune cells in endometrial lesions. Our findings suggest that IL-10 may suppress immunity against endometrial implants, contributing to development of endometriosis.

Endometriosis and infertility: a review of the pathogenesis and treatment of endometriosis-associated infertility

Endometriois has been associated with infertility; however, the mechanisms by which it affects fertility are still not fully understood. This article reviews the proposed mechanisms of endometriosis pathogenesis, its effects on fertility, and treatments of endometriosis-associated infertility. Theories on the cause of the disease include retrograde menstruation, coelomic metaplasia, altered immunity, stem cells, and genetics. Endometriosis affects gametes and embryos, the fallopian tubes and embryo transport, and the eutopic endometrium; these abnormalities likely all impact fertility. Current treatment options of endometriosis-associated infertility include surgery, superovulation with intrauterine insemination, and in vitro fertilization. We also discuss potential future treatments for endometriosis-related infertility.

TGF-β1 induces proteinase-activated receptor 2 (PAR2) expression in endometriotic stromal cells and stimulates PAR2 activation-induced secretion of IL-6

BACKGROUND

Proteinase-activated receptor 2 (PAR2) is a G-protein-coupled receptor that is activated by several serine proteases. PAR2 activation in endometriotic stromal cells (ESCs) has been implicated in the development of endometriosis but the regulatory mechanism of PAR2 expression in ESC is unknown. Our objective was to study the mechanism by which PAR2 expression may be regulated in endometriotic lesions.

METHODS

Primary cultures of ESCs were treated with transforming growth factor-β (TGF-β) 1, tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β), and the expression of PAR2 was examined by real-time quantitative PCR. ESCs pretreated with or without TGF-β1 were treated with PAR2 agonist peptide (PAR2AP) and the secretion of the pro-endometriotic cytokine, IL-6, was measured using a specific enzyme-linked immunosorbent assay. Effects of TGF-β type 1 inhibitor, SB431542, and PAR2 small interfering RNA (siRNA) on the TGF-β1 stimulation of PAR2 gene expression and PAR2AP-induced IL-6 secretion were also evaluated. To study intracellular signaling, effects of inhibitors of mitogen-activated protein kinases (MAPKs) and phosphoinositide 3-kinase (PI3K) and of Smad4 siRNA on the TGF-β1-induced PAR2 gene expression were studied.

RESULTS

Only TGF-β1, but neither TNF-α nor IL-1β, increased gene expression of PAR2. Activation of PAR2 with PAR2AP increased the secretion of IL-6 from ESCs. As expected, TGF-β1 pretreatment dose-dependently enhanced the PAR2AP-induced increase in IL-6 secretion from ESCs. Treatment of ESCs with the TGF-β type 1 inhibitor, SB431542, inhibited both TGF-β1-stimulation of PAR2 gene expression and PAR2AP-induced IL-6 secretion. Transfection of ESCs with PAR2 siRNA produced a similar inhibition of IL-6 secretion. The TGF-β1-induced increase in PAR2 gene expression was repressed by inhibition of p38 MAPK, p42/44 MAPK or PI3K, but not by knockdown of Smad4 expression.

CONCLUSIONS

In view of significant roles of PAR2 and IL-6 in endometriosis, the TGF-β1-induced increase in PAR2 expression may be an elaborate mechanism that augments the progression of the disease.

Proteolytic tailoring of the heat shock protein 70 and its implications in the pathogenesis of endometriosis

OBJECTIVE

To investigate the mechanism underlying the appearance of a 20-kd HSP70 fragment and its consequences in the ectopic endometrium of endometriosis patients.

DESIGN

Experimental study.

SETTING

Research institute and obstetrics and gynecology clinic.

PATIENT(S)

Participants with (n = 18) and without (n = 20) endometriosis.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Reverse-transcription polymerase chain reaction, protease assays, and in silico tools were used to investigate the origin of the 20-kd HSP70 fragment. Immunocolocalization studies were carried out to determine whether subtilisin/kexin isozyme 1 (SKI-1) and HSP70 are colocalized. Expression and localization of surrogate markers of inflammation, such as nuclear factor NF-κB and interleukin IL-6 were examined by immunoblotting and in situ studies.

RESULT(S)

HSP70 is posttranslationally processed into a 20-kd fragment by SKI-1, a protease of the subtilisin family, in ectopic endometrium (ECE). Immunocolocalization studies revealed spatial proximity of SKI-1 and HSP70 in ECE. Furthermore, ECE demonstrated nuclear localization of the transcription factor, NF-κB and high expression of its target protein, IL-6.

CONCLUSION(S)

This study hints at the possible mechanisms underlying the trimming of HSP70 in ECE and also at the role of proteases in the pathogenesis of endometriosis. The possible repercussions of HSP70 fragmentation include dysregulation of key regulatory proteins, resulting in the escalation of inflammatory events in endometriotic lesions.

Endometriosis-associated infertility: double intrauterine insemination improves fecundity in patients positive for antiendometrial antibodies

PROBLEM

Prospective registry study evaluating effects of endometriosis (E) and serum antiendometrial antibodies (AEA) on fecundity in intrauterine insemination (IUI) cycles.

METHOD OF STUDY

AEA assays on 572 consecutive women receiving 969 single and 274 double IUI cycles. Logistic regression was utilized.

RESULTS

Fecundity was 11.5% (143/1243 cycles). Double IUI improved fecundity with significance achieved in certain study groups. Compared to the AEA- subgroup, all study groups except for the E+ AEA- group had significantly lower fecundity. Two study groups receiving double IUI had significantly increased fecundity, E- AEA+ (OR: 5.1, CI: 1.1-22.7, P=0.032) and E+ AEA+ (OR: 4.1, CI: 1.2-14.0, P=0.025) and significant predictors of pregnancy (E- AEA+, OR: 7.8, CI: 1.7-36.2, P=0.009 and E+ AEA+, OR: 4.2, CI: 1.2-15.1, P=0.026).

CONCLUSION

Double IUI improves fecundity in AEA+ patients. E-associated infertility is better diagnosed by the AEA assay than by surgery. Double IUI should be attempted prior to assisted reproductive technologies in AEA+ patients with normal fallopian tubes.

Doxycycline causes regression of endometriotic implants: a rat model

BACKGROUND

Doxycycline (Dox) has a number of non-antibiotic properties. One of them is the inhibition of matrix metalloproteinase (MMP) activity. The aim of this study was to assess the effects of Dox in a rat endometriosis model.

METHODS

Endometriosis was surgically induced in 40 rats by transplanting of endometrial tissue. After 3 weeks, repeat laparotomies were performed to check the implants and the animals were randomized into four groups: Group I, low-dose Dox (5 mg/kg/day); Group II, high-dose Dox (40 mg/kg/day); Group III, leuprolide acetate 1 mg/kg single dose, s.c.; and Group VI (controls), no medication. The treatment, initiated on the day of surgery and continuing for 3 weeks, was administered to the study groups. Three weeks later, the rats were euthanized and the implants were evaluated morphologically and histologically for immunoreactivity of MMP-2 and -9, and interleukin-6 (IL-6) concentration in the peritoneal fluid was assayed.

RESULTS

Treatment with leuprolide acetate, or high-dose or low-dose Dox caused significant decreases in the implant areas compared with the controls (P = 0.03, P = 0.006, and P = 0.001, respectively). IL-6 levels in peritoneal fluid decreased in Group I (P = 0.02) and Group III (P < 0.05). MMP H scores were significantly lower in the group that received low-dose Dox in both epithelial and stromal MMP-2 and -9 immunostaining when compared with the control group [P = 0.048, P = 0.002, P = 0.007 and P = 0.002, respectively, MMP-2 (epithelia), MMP-2 (stroma), MMP-9 (epithelia) and MMP-9 (stroma)].

CONCLUSIONS

Low-dose Dox caused regression of endometriosis in this experimental rat model.

L-carnitine supplementation reduces oocyte cytoskeleton damage and embryo apoptosis induced by incubation in peritoneal fluid from patients with endometriosis

OBJECTIVE

To investigate the protective effect of L-carnitine (LC) against deleterious substances present in the peritoneal fluid (PF) of patients with endometriosis, which may affect the oocyte cytoskeleton and embryogenesis.

DESIGN

Experimental study.

SETTING

Research embryology laboratory at an academic hospital.

PATIENT(S)

Frozen metaphase II mouse oocytes and embryos.

INTERVENTION(S)

One hundred metaphase II mouse oocytes were divided into five groups and incubated: PF from endometriosis patients; PF from endometriosis patients + LC; PF from tubal ligation patients (patient control); LC only; and human tubal fluid (HTF) alone. A total of 180 eight-cell mouse embryos were divided into: endometriosis only; tubal ligation only; endometriosis + LC; LC alone; and HTF alone.

MAIN OUTCOME MEASURE(S)

Protective effect of LC on oocytes and embryos.

RESULT(S)

Incubation of the oocytes and the embryos with PF from patients with endometriosis statistically significantly damaged the oocyte microtubules and chromosomes and increased embryo apoptosis compared with controls. Incubation with LC (0.6 mg/mL) statistically significantly improved microtubule and chromosome structure and decreased the level of embryo apoptosis.

CONCLUSION(S)

We propose the use of LC as a supplement in patients with endometriosis, a novel approach that may help improve in vitro fertilization outcome in these patients.

Expression of human endogenous gammaretroviral sequences in endometriosis and ovarian cancer

Endogenous retroviruses (ERVs) probably originate from ancient germ cell infections by exogenous retroviruses. A high expression of retroviruses in reproductive tissue increases the risk of viral transmission to germ line cells. We therefore investigated the expression of human ERVs (HERVs) in normal endometrium, endometriosis, normal ovaries, and ovarian cancer. Four real-time PCRs (QPCRs) for HERV-E, HERV-I/T, HERV-H, and HERV-W, respectively, and an expression control gene were used. HERV-E RNA expression was significantly higher in endometriotic tissue (average, SD) than in normal endometrium (average, SD), both measured as ratios versus control gene expression and as. HERV-E and HERV-W RNA were higher in normal ovarian tissue than in ovarian cancer. This illustrates that HERV expression is not automatically higher in malignant tissues. The other HERV PCRs did not show expression patterns as distinctive as HERVE and HERV-W in the two kinds of reproductive tissue. A small number of candidate HERV-E loci from which the transcription took place were identified by sequencing of amplimers. The role of HERV-E and HERV-W in endometriosis merits further investigation.

The interleukin-6 -174G/C promoter polymorphism is not associated with endometriosis in South Indian women

OBJECTIVE

To investigate the association of the -174 G/C promoter polymorphism of the interleukin-6 (IL-6) gene with endometriosis in South Indian women.

METHODS

The genotype frequencies of the common IL-6 -174 G/C polymorphism were compared in infertility patients with (n = 232) and without (n = 210) endometriosis using polymerase chain reaction (PCR) and sequencing analysis.

RESULTS

The genotype frequencies among the cases and controls were G/G 62.9% and 71.9%, G/C 34.1% and 25.2%, and C/C 3.0% and 2.9%. The G and C allele frequencies were 80% and 84.6%, and 20% and 15.4%, respectively. There were no statistically significant differences in the genotype distributions or allele frequencies between the cases and controls (P = .12).

CONCLUSIONS

The present study demonstrates no significant association between the IL-6 -174 G/C promoter polymorphism and endometriosis in South Indian women.

Correlation between transcranial interleukin-6 gradient and outcome in patients with acute brain injury

OBJECTIVE

This study was performed to examine both brain and systemic interleukin-6 (IL-6) release in patients with an acute brain injury (ABI), to study whether a correlation exists between the transcranial IL-6 gradient during the first days after injury and prognosis, and finally, to investigate the relationship between a nucleotide polymorphism at position -174 in the promoter of the gene encoding IL-6, IL-6 responsiveness, and clinical evolution.

DESIGN

Prospective clinical investigation.

SETTING

A 19-bed intensive care unit in a university hospital.

PATIENTS AND METHODS

A total of 62 patients were followed up for 3 days after acute brain injury, and both their arterial and jugular IL-6 levels were measured serially and at the moment of brain death diagnosis. Genetic polymorphism of IL-6 was also determined in all patients. Data were correlated with those from score procedures for clinical severity. Neurologic outcome was graded according to the Glasgow Outcome Scale 6 months after injury. IL-6 levels and IL-6 genotyping was performed in control healthy individuals.

MAIN RESULTS

There is a significant transcranial IL-6 gradient at admission and at the moment of brain death. The gradient is higher in those patients who evolved toward a fatal outcome during the first 6 months after injury (p <.001). There is significant correlation between the transcranial IL-6 gradient and the acute brain injury severity.

CONCLUSIONS

IL-6 is elevated in patients with acute brain injury, and a significant relationship exits between the severity of acute brain injury and the transcranial IL-6 gradient at admission. It can be considered to be a prognosis marker at admission. When data at the moment of brain death are considered, venous IL-6 (p <.01) and the transcranial IL-6 gradient (p <.005) are significantly higher than at the time of admission. Although the IL-6 C allele is associated with significantly lower concentrations of IL-6, there was no correlation between low or high IL-6 responders and patient outcome.

Was Sampson wrong?

OBJECTIVE

Sampson's theory of reflux menstruation suggests that endometriosis is one form of a condition known as an autotransplant. This study seeks to characterize autotransplants as they are described in the literature and to determine whether endometriosis resembles an autotransplant.

DESIGN

Literature review of published studies containing the following types of information: [1] characterization of the histologic features, immunohistochemistry, or structural function of autotransplants; and [2] comparisons of endometriosis with endometrium.

MAIN OUTCOME MEASURE(S)

Characteristics of multiple types of autotransplants were noted. Similarity or dissimilarity of endometriosis and endometrium was tabulated to judge qualitatively whether the bulk of the evidence supports the notion that endometriosis is an autotransplant.

RESULT(S)

Autotransplants remain very similar or identical to eutopic tissues of origin, regardless of the length of time following autotransplantation. Endometriosis differs in many profound and fundamental ways from eutopic endometrium, including clonality of origin, enzymatic activity, protein expression, and histologic and morphologic characteristics. A minority of studies has found similarities between endometriosis and eutopic endometrium.

CONCLUSION(S)

Endometriosis is dissimilar to eutopic endometrium and therefore lacks characteristics of an autotransplant. Sampson's theory of origin of endometriosis is not supported by the results of this study. Studies of experimental endometriosis that have not used menstrual endometrium may be misleading.

Modulation of neutrophil apoptosis by plasma and peritoneal fluid from patients with advanced endometriosis

BACKGROUND

The increased production of pro-inflammatory chemoattractant cytokines for neutrophils in endometriosis suggests that changes in the immune system play an important role in the pathophysiology of endometriosis. The effects of plasma and peritoneal fluid from patients with advanced endometriosis on the apoptosis of neutrophils were investigated.

METHODS

Apoptotic changes of neutrophils were evaluated by morphological changes using Giemsa staining. Apoptosis was confirmed by DNA electrophoretic analysis.

RESULTS

Compared with the plasma (n = 20) and peritoneal fluid (n = 5) of healthy controls, the addition of 10% plasma (n = 20) and peritoneal fluid (n = 10) from patients with endometriosis to an in-vitro culture of neutrophils from healthy subjects reduced the percentage of apoptotic cells from 65.3 +/- 6.6 to 27.2 +/- 4.6% (P < 0.001) and from 45.3 +/- 4.8 to 10.5 +/- 4.3% (P < 0.001) respectively. Neutralizing interleukin-8 antibody abrogated the delay of neutrophil apoptosis induced by peritoneal fluid, but not in the plasma of endometriosis patients.

CONCLUSIONS

These findings show that interleukin-8 is one of the neutrophil survival factors in the peritoneal fluid of endometriosis patients and that an unidentified survival factor is also present in the plasma of patients with endometriosis.

The genetic basis of endometriosis

Family studies have long suggested a role for genetic factors in the aetiology of endometriosis. The influence of genes on disease development has mainly been researched independently of environmental factors, yet their interaction must play an important role. Greater exposure to retrograde menstruation and oestrogen is likely to increase the risk of endometriosis; toxic compounds such as dioxin may increase the risk, although the only direct evidence has come from primate studies. Previous association studies implicated GALT (a gene involved in galactose metabolism), and GSTM1 and NAT2 (genes encoding for the detoxification enzymes) as possible disease susceptibility genes. Recent findings have added to the evidence for the involvement of GSTM1 and NAT2, but have cast doubt on the role of GALT. However, the design of many genetic and epidemiological studies has been inadequate with respect to sample size, consistency in phenotype definition, and the choice of control populations. These features are likely to influence results, and could partly explain the lack of consistency in the findings. Future studies should use a consistent disease definition and be of appropriate epidemiological design.

Expression of the cyclin-dependent kinase inhibitor p27Kip1 in eutopic endometrium and peritoneal endometriosis

OBJECTIVE

This study was undertaken to evaluate the immunohistochemical expression of the cell cycle inhibitor p27Kip1 and proliferation marker Ki67 in peritoneal endometriosis and eutopic endometrium.

DESIGN

Prospective study.

SETTING

University hospital.

PATIENT(S)

Thirty-one patients with peritoneal endometriosis.

INTERVENTION(S)

During laparoscopy, 25 samples of predominantly red peritoneal lesions and 27 samples of predominantly black peritoneal lesions were collected from 31 patients with endometriosis. Eutopic endometrium from 25 patients with endometriosis was collected by curettage during laparoscopy or just after surgery.

MAIN OUTCOME MEASURE(S)

The percentage of glandular and stromal cells exhibiting positive staining for p27Kip1 and Ki67 (labeling index, LI) was determined.

RESULT(S)

The LI of stromal cells in red peritoneal lesions for both p27Kip1 and Ki67 was similar to that of proliferative eutopic endometrium. Although the LI of glandular epithelial cells for Ki67 in red lesions was comparable to that of proliferative eutopic endometrium, the LI for p27Kip1 was significantly higher. Furthermore, we detected a significantly higher LI of glandular epithelial and stromal cells for p27Kip1 in black lesions compared with red lesions.

CONCLUSION(S)

Our results suggest that expression of the cyclin kinase inhibitor p27Kip1 is involved in the natural history and progression of peritoneal endometriosis.

Endometriosis-associated infertility

This review summarizes the recent literature examining the relationship between endometriosis and infertility. It is clear that the advanced stage of the disease and the mechanical disruption of the pelvic anatomy may cause infertility. The link between early stage endometriosis and infertility remains a source of controversy. Management plans must be individualized contingent upon the stage of disease, the age of the patient and the duration of infertility. The preponderance of data suggests that ablative therapy at the time of laparoscopy is as good as, or superior to expectant or medical therapy. With the exception of IVF/ET, ovarian suppression with GnRH agonists is not warranted in endometriosis-associated infertility. Controlled ovarian hyperstimulation with IUI is appropriate therapy in women with minimal-to-mild and surgically corrected endometriosis.