Elevated levels of interleukin-6 in the follicular fluid at the time of oocyte retrieval for in vitro fertilization may predict the development of early-form ovarian hyperstimulation syndrome

Interleukin-6 stimulates in vitro development of late-stage ovine embryos

The effect of interleukin-6 (IL-6) supplementation during the different phases of in vitro embryo culturing (IVC) on embryo development and embryonic gene expression was studied in ovine. IL-6 was added to IVC medium during the late phases (72-192 h; 5, 10, and 25 ng/ml IL-6) or entire period (0-192 h; 10 ng/ml IL-6) of IVC to determine its effect on embryo development. Further, the effect of IL-6 (10 ng/ml) supplementation at the 72 h of IVC on gene expressions associated with JAK/STAT signalling and pluripotency in 8-16 cell embryos (1 h post-supplementation) and compact morulae (48 h post-supplementation), and apoptosis and primitive endoderm (PrE) development in compact morulae was investigated. The supplementation of 10 ng/ml IL-6 during the late phases of IVC significantly (P < 0.05) increased blastocyst formation (35.2 ± 1.52%) compared to the control (21.1 ± 1.11%), and 5 ng/ml (25.9 ± 2.98%) or 25 ng/ml (16.5 ± 0.73%) IL-6 groups. Conversely, IL-6 (10 ng/ml) treatment throughout the IVC period significantly (P < 0.05) decreased the rate of cleavage (55.4 ± 1.57%) and blastocyst formation (14.5 ± 1.28%) compared to the control group (65.8 ± 1.35% and 21.5 ± 0.97%, respectively). In 8-16 cell embryos and compact morulae, the IL-6 treatment significantly (P < 0.05) affected the expression of genes associated with JAK/STAT signalling and pluripotency. Further, the treatment significantly (P < 0.05) downregulated BAX and CASP3, and upregulated GATA6 expression in compact morulae. In conclusion, IL-6 supplementation affected the in vitro development of ovine embryos in a dose- and time-dependent manner. The beneficial effect of IL-6 on the development of late-stage embryos was mediated through the changes in gene expressions associated with JAK/STAT signalling, pluripotency, apoptosis and PrE development.

A review of autoimmunity and immune profiles in patients with primary ovarian insufficiency

Primary ovarian insufficiency (POI) is a complicated clinical syndrome characterized by progressive deterioration of ovarian function. Autoimmunity is one of the main pathogenic factors affecting approximately 10% to 55% of POI cases. This review mainly focuses on the role of autoimmunity in the pathophysiology of POI and the potential therapies for autoimmunity-related POI. This review concluded that various markers of ovarian reserve, principally anti-Müllerian hormone, could be negatively affected by autoimmune diseases. The presence of lymphocytic oophoritis, anti-ovarian autoantibodies, and concurrent autoimmune diseases, are the main characteristics of autoimmune POI. T lymphocytes play the most important role in the immune pathogenesis of POI, followed by disorders of other immune cells and the imbalance between pro-inflammatory and anti-inflammatory cytokines. A comprehensive understanding of immune characteristics of patients with autoimmune POI and the underlying mechanisms is essential for novel approaches of treatment and intervention for autoimmune POI.

Enhanced Inflammatory Transcriptome in the Granulosa Cells of Women With Polycystic Ovarian Syndrome

CONTEXT

Polycystic ovarian syndrome (PCOS), the most common endocrine disorder of reproductive-aged women, is associated with systemic low-grade inflammation.

OBJECTIVE

We propose that increased or altered intrafollicular inflammatory reactions also occur in periovulatory follicles of PCOS patients.

DESIGN

Gene profiling and quantitative PCR (qPCR) analyses in granulosa-lutein cells (GCs) collected from PCOS and non-PCOS women undergoing in vitro fertilization were compared with serum and follicular fluid (FF) levels of cytokines and chemokines.

SETTING

This was a university-based study.

PATIENTS

Twenty-one PCOS and 45 control patients were recruited: demographic, hormone, body mass index, and pregnancy outcomes were abstracted from patient data files.

INTERVENTIONS

GC cytokine/chemokine mRNAs were identified and analyzed by gene-chip microarrays/qPCR before and after culture with human chorionic gonadotropin, DHT, IL-6, or IL-8; serum/FF cytokine levels were also analyzed.

MAIN OUTCOME MEASURES

Relative serum/FF cytokine levels and GC cytokine expression before and after culture were compared and related to body mass index.

RESULTS

The following results were found: 1) PCOS GCs express elevated transcripts encoding cytokines, chemokines, and immune cell markers, 2) based on gene profiling and qPCR analyses, obese PCOS patients define a distinct PCOS disease subtype with the most dramatic increases in proinflammatory and immune-related factors, and 3) human chorionic gonadotropin and DHT increased cytokine production in cultured GCs, whereas cytokines augmented cytokine and vascular genes, indicating that hyperandrogenism/elevated LH and obesity in PCOS women augment intrafollicular cytokine production.

CONCLUSIONS

Intrafollicular androgens and cytokines likely comprise a local regulatory loop that impacts GC expression of cytokines and chemokines and the presence of immune cells; this loop is further enhanced in the obese PCOS subtype.

The role of IL-6 trans-signaling in vascular leakage: implications for ovarian hyperstimulation syndrome in a murine model

CONTEXT

The inflammatory cytokine IL-6 is related to ovarian hyperstimulation syndrome (OHSS), although the functional role of IL-6 in OHSS remains largely unknown.

OBJECTIVE

A key feature of the IL-6 response is that its regulation is dependent on IL-6 trans-signaling via soluble IL-6 receptor-α (sIL-6Rα). The objective of the study was to elucidate the mechanistic role of IL-6 trans-signaling in the vascular leakage that underlies the pathophysiology of OHSS.

DESIGN

Ovarian endothelial cells (ECs) and granulosa-lutein cells were obtained from women undergoing in vitro fertilization. OHSS was induced in mice by administering gonadotropins for 2 days followed by human chorionic gonadotropin. The functional role of IL-6 trans-signaling in OHSS was verified using the designer cytokines Hyper IL-6 and sgp130-Fc.

RESULTS

The follicular fluid levels of sIL-6Rα were elevated in women at high risk for OHSS. In the murine OHSS model, stimulation with gonadotropins significantly induces ovarian IL-6 and sIL-6Rα expression. In vitro, FSH induces de novo sIL-6Rα synthesis in granulosa-lutein cells through a protein kinase C-dependent pathway. In addition, sIL-6Rα was released by leukocytes in the presence of conditioned medium from human chorionic gonadotropin-treated granulosa-lutein cells. Ovarian ECs responded to the IL-6Rα-IL-6 complex (Hyper IL-6) but not to IL-6 alone. With activation of signal transducer and activator of transcription 3 (STAT3) and ERK, Hyper IL-6 increased vascular endothelial growth factor expression and the vascular permeability of ECs. Selective blockade of IL-6 trans-signaling by sgp130-Fc significantly inhibited vascular endothelial growth factor expression and prevented OHSS in mice.

CONCLUSIONS

IL-6 trans-signaling is activated during the ovarian stimulation process. Our findings provide insight into the biologic effects of IL-6 trans-signaling in OHSS and highlight that IL-6 trans-signaling can induce vascular leakage in this disease.

Reproductive aging is associated with altered gene expression in human luteinized granulosa cells

Declining reproductive success with aging is attributable to qualitative and quantitative deterioration in oocytes, which are nurtured by granulosa cells (GCs). This prospective study assesses whether reproductive aging is accompanied by differential gene expression in luteinized GCs from in vitro fertilization (IVF) patients. Women with nonovarian infertility etiologies were categorized as younger (< or =30, n = 3) or older (> or =40, n = 3). During oocyte retrieval, mural GCs were isolated; messenger RNA (mRNA) was extracted and transcribed for complementary DNA (cDNA) microarray analysis. Differential gene expression was confirmed by real-time polymerase chain reaction (PCR). Analysis revealed 120 genes were differentially expressed. Three genes were upregulated and 117 were downregulated (including interleukin [IL]-1beta, IL-1R2, and IL-6R) in GCs of older versus younger patients. Our data provide evidence of downregulation in IL-1 and IL-6 gene families in luteinized GCs with advancing age. Given previously recognized roles for the IL gene family in folliculogenesis and ovulation, our findings may partly explain ovulatory and luteal dysfunctions associated with reproductive aging.

Follicular fluid vascular endothelial growth factor and tumour necrosis factor α concentrations in patients with endometriosis undergoing ICSI

The aim of this study was to investigate follicular fluid vascular endothelial growth factor (VEGF) and tumour necrosis factor alpha (TNFalpha) concentrations in endometriosis, and their effect on the outcome of intracytoplasmic sperm injection (ICSI). A prospective study was performed among patients who had either a laparoscopic diagnosis of endometriosis (n = 48) or who had normal laparoscopic findings with unexplained infertility (n = 43). The number of gonadotrophin units, peak oestradiol concentrations, number of oocytes retrieved, fertilization, cleavage and pregnancy rates, and number of embryos transferred, were the main outcome measurements. There was no difference in these parameters between the two study groups. Significantly higher concentrations of VEGF were found in the endometriosis group (P = 0.031), but there was no difference in TNFalpha concentrations. No relationship was found between VEGF and TNFalpha concentrations and ICSI outcome. Despite a higher concentration of intrafollicular VEGF in the endometriosis group, it was concluded that this parameter had no predictive value with respect to ICSI outcome. In addition, intrafollicular TNFalpha concentrations were not different in the endometriosis group and there was no relationship between VEGF or TNFalpha concentrations and the outcomes measured.

Interleukin-18 is High in the Serum of IVF Pregnancies with Ovarian Hyperstimulation Syndrome*

PROBLEM

The presence of interleukin-18 (IL-18) in serum and pre-ovulatory follicular fluid (FF) and its possible correlation to in-vitro fertilization/embryo transfer (IVF/ET) outcome and ovarian hyperstimulation syndrome (OHSS) development.

METHOD OF STUDY

A prospective study was carried out. Assays for serum and pooled pre-ovulatory FF levels of IL-18 were performed on 30 patients who underwent oocyte retrieval for IVF/ET.

RESULTS

Mean serum and FF levels of IL-18 were 370.4 +/- 224 and 228.9 +/- 208 pg/mL, respectively (r = 0.77, P < 0.0001). Levels of FF IL-18 were comparable between the two ovaries (right = 221 +/- 166.8 pg/mL, left = 237 +/- 171.9 pg/mL; r = 0.7550, P = 0.49). A positive correlation was found between IL-18 FF levels and number of retrieved oocytes (r = 0.45; P = 0.019). In three patients (10%) who developed OHSS, the mean serum level of IL-18 at day of ovum pickup was significantly higher compared with patients without OHSS (620 +/- 196 pg/mL versus 345 +/- 251 pg/mL, respectively, P = 0.04).

CONCLUSIONS

Both pre-ovulatory FF and serum levels of IL-18 correlate with the number of retrieved oocytes. The serum IL-18 level at day of ovum pickup may predict consequent development of OHSS. Further investigations are warranted to determine the role of IL-18 in the folliculogenesis and OHSS pathogenesis.

Comparison between cytokine concentration in follicular fluid of poor and high responder patients and their influence of ICSI-outcome

OBJECTIVE

The aim of this study was to compare the cytokine concentration in follicular fluid (FF) of low and high responder intracytoplasmic sperm injection (ICSI) patients and to find out the impact of these cytokines in FF on ICSI outcome.

DESIGN

The levels of insulin-like growth factor (IGF)-I, IL-6, IL-8, epidermal growth factor (EGF), platelet-derived growth factor (PDGF), granulocyte-macrophage-colony stimulating factor (GM-CSF) were measured from low and high responder ICSI patients, the results were compared between the two groups and their influence on ICSI outcome was analysed.

MATERIAL AND METHODS

A total of 49 low (G.I) and 34 high (G.II) responder patients were enrolled in this study. FF was collected at the time of oocyte retrieval and measured either by enzyme-linked immunosorbent assay (IL-6, IL8, EGF, PDGF, GM-CSF) or radio immuno assay (IGF-I).

RESULTS

The concentration of IL-6 (pg/mL), IL-8 (pg/mL), IGF-I (ng/mL), PDGF (pg/mL), EGF (pg/mL), GM-CSF (pg/mL) in G.I was 6.0 +/- 4.3, 288.1 +/- 139.2, 0.416 +/- 0.089, 249.8 +/- 150.1, 9.12 +/- 5.5 and 1.45 +/- 2.10 and the corresponding value in G.II was 7.4 +/- 4.8, 208.6 +/- 64.0, 0.431 +/- 0.094, 387.6 +/- 36.0, 8.9 +/- 5.4 and 1.8 +/- 3.3, respectively. Only the PDGF concentration showed a significant (P = 0.007) difference between the two groups. Besides, negative correlations were found between PDGF and fertilization rate (r = -0.287; P = 0.046) of G.I. The mean number of retrieved (6.4 +/- 2.3 versus. 15.7 +/- 5.4) and fertilized (3.6 +/- 1.6 versus 7.0 +/- 4.5) oocytes differ significantly (P = 0.001) between the two groups. The fertilization rate was significantly higher in G.I than in G.II (60.9 +/- 25.1 versus 43.4 +/- 20.7%).

CONCLUSION

There was no significant difference between IGF-I, IL-6, IL-8, EGF and GM-CSF concentrations of low and high responder patients. Besides, PDGF was significantly (P = 0.007) higher in high responder compared with low responder patients. Moreover, in poor responder patients, a negative correlation was found between PDGF and fertilization rate. However, the cytokine levels in FF of the patients undergoing controlled ovarian hyperstimulation for ICSI could not be used as a marker of oocyte fertilization and implantation potential.

Relationship between ovarian stimulation regimen and interleukin level in pre-ovulatory follicular fluid and their effect on ICSI outcome

PROBLEM

The aims of this study were (i) to identify the presence and concentration of interleukin-6 (IL-6), IL-8 and granulocyte-macrophage colony-stimulating factor (GM-CSF) in pre-ovulatory follicular fluid (FF) in patients undergoing controlled ovarian hyperstimulation regimen for intracytoplasmic sperm injection (ICSI) with recombinant human follicle stimulating hormone (rFSH) (G.1), hMG (G.2) or rFSH/ hMG (G.3) treatment and (ii) to determine whether controlled ovarian hyperstimulation stimulation regimen could affect the concentration of these investigated interleukins and as a consequences the ICSI outcome. (iii) Moreover, it was intended to clarify the association between these investigated parameters and the peripheral blood level of estradiol 17-beta, progesterone, leuteinizing hormone (LH) at the day of oocyte retrieval and (iv) finally to find out whether these interleukin concentrations in FF could be considered as an additional parameter for predicting fertilization and pregnancy outcome in ICSI patients.

MATERIAL AND METHODS

Interleukin-6, IL-8 and GM-CSF concentrations were determined in the FF of 85 patients. The levels of these interleukins were measured by the enzyme-linked immunosorbent assay (ELISA) technique, using commercially available kits.

RESULTS

Interleukin-6 (6.5 +/- 4.6 pg/mL), IL-8 (222.9 +/- 163.4 pg/mL) and GM-CSF (1.6 +/- 2.7 pg/mL) were present in pre-ovulatory FF in ICSI patients. No significant difference in the mean concentration of IL-6, IL-8 and GM-CSF was found between the groups. Moreover, there was no correlation between these interleukin levels in FF and steroid hormone concentration in the peripheral blood.

CONCLUSIONS

Interleukin-6, IL-8 and GM-CSF were found in FF of patients undergoing ovarian hyperstimulation for ICSI treatment. The stimulation protocols showed no influence on these interleukin levels in FF. Moreover, no correlation was found between these investigated interleukins and steroid hormone concentrations in peripheral blood or ICSI outcome. Therefore, the determination of interleukin level in FF of patients undergoing ovarian hyperstimulation for ICSI therapy could not be recommended as a prognostic factor for ICSI outcome.

Vascular endothelial growth factor, interleukin-6 and interleukin-2 in serum and follicular fluid of patients with ovarian hyperstimulation syndrome

BACKGROUND

The pathogenesis of ovarian hyperstimulation syndrome (OHSS) is not completely understood.

OBJECTIVE

To investigate the presence of VEGF, IL-6 and IL-2, in serum and follicular fluid, in patients developing severe OHSS.

STUDY DESIGN

We enrolled 101 women undergoing in vitro fertilization. Eight patients developing severe OHSS were compared with 43 high risk patients and 50 controls. We analyzed VEGF and IL-6 in serum collected before hCG administration, and in both serum and follicular fluid on the day of oocyte retrieval.

RESULTS

OHSS patients presented follicular fluid IL-6 levels higher than both the patients at risk and controls (P<0.05). On the day of the oocyte retrieval the patients developing OHSS showed serum and follicular VEGF values higher than the ones of the patients at risk (P<0.05). Serum and follicular fluid IL-2 levels showed no differences between the examined groups. IL-2, IL-6 and VEGF values were not correlated with each other.

CONCLUSIONS

Angiogenesis and inflammation processes are both present in severe OHSS.

Ovarian hyperstimulation syndrome: an endocrinopathy?

Ovarian hyperstimulation syndrome remains a significant but incompletely understood complication of ovarian stimulation. Evidence has accumulated regarding a role for various cytokines, in particular vascular endothelial growth factor, in its occurrence. However, the pathogenesis of ovarian hyperstimulation syndrome is likely to be complex and may involve a network of interacting cytokines and endocrine factors. Recent studies suggest links between specific cytokines and specific functional abnormalities in severe ovarian hyperstimulation syndrome. Two clinical forms of ovarian hyperstimulation syndrome may be distinguished, based on time of onset, with implications for the prediction and prevention of ovarian hyperstimulation syndrome in clinical practice.

Relationships between concentrations of tumor necrosis factor-alpha and nitric oxide in follicular fluid and oocyte quality

PURPOSE

Our objective was to explain a relationship between concentrations of tumor necrosis factor-alpha (TNF-alpha) and nitric oxide (NO) in follicular fluid, oocyte quality, and outcomes of in vitro fertilization--embryo transfer (IVF-ET).

METHODS

The concentrations of TNF-alpha and NO were measured in 115 follicular fluid samples collected from 43 patients undergoing IVF-ET program, due to tubal obstruction, some with endometriosis (8 patients) or hydrosalpinx (5 patients). A correlation of these factors concentrations and the oocyte quality, the oocyte maturity, and infertility-associated diseases was analyzed.

RESULTS

No correlation was found between concentrations of NO and TNF-alpha in follicular fluid. NO concentrations in follicular fluids were significantly higher in patients with endometriosis (P < 0.001) or hydrosalpinx (P < 0.01) compared to the patients with just tubal obstruction. Follicular NO concentration differences according to oocyte maturity and oocyte quality were not found. In contrast, TNF-alpha concentrations in follicular fluids were significantly higher in poor quality oocytes (P < 0.05) but were not associated with infertility-associated diseases, such as hydrosalphinx or endometriosis,and the oocyte maturity. No significant differences in follicular levels of NO and TNF-alpha as well as IVF-ET parameters of pregnant and nonpregnant groups were revealed.

CONCLUSIONS

There is no significant correlation between the concentrations of NO and TNF-alpha in follicular fluid. NO levels in follicular fluid are altered in infertility-associated diseases. However, TNF-alpha levels but not NO levels influence oocyte quality. These results suggest that the production of NO and TNF-alpha in follicular fluid may be regulated via different pathways and can be tempered with infertility-associated diseases, thereby influencing oocyte quality locally.

Prognostic importance of serial cytokine changes in ascites and pleural effusion in women with severe ovarian hyperstimulation syndrome

OBJECTIVE

To determine the prognostic value of various cytokine levels in ascites and pleural effusion during the evolution of severe ovarian hyperstimulation syndrome (OHSS).

DESIGN

A longitudinal study.

SETTING

University teaching hospital.

PATIENT(S)

Twenty patients with severe OHSS who required either paracentesis or thoracentesis or both from whom ascites (n = 56) or pleural effusion (n = 12) samples were obtained. Control peritoneal fluid was obtained from 20 patients undergoing ovarian stimulation for IVF.

INTERVENTION(S)

Abdominal paracentesis for tense ascites and thoracentesis for massive pleural effusion. Control peritoneal fluid was obtained before oocyte retrieval.

MAIN OUTCOME MEASURE(S)

Levels of interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6), interleukin-8 (IL-8), tumor necrosis factor-alpha (TNF-alpha), vascular endothelial growth factor (VEGF), E2, and progesterone concentrations in ascites and pleural effusion.

RESULT(S)

Levels of VEGF and IL-6 in ascites dropped significantly during the course of OHSS and were not correlated with E2 concentrations. Levels of VEGF were significantly correlated with levels of IL-1 beta, IL-8, and TNF-alpha, as well as progesterone concentrations, hematocrit, and white blood cell counts. None of the cytokine levels measured in pleural effusion were correlated with the course of OHSS.

CONCLUSION(S)

These results suggest that local cytokines might be involved in the evolution of severe OHSS and possibly serve as prognostic markers for this syndrome.