In controlled ovarian hyperstimulation, steroid production, oocyte retrieval, and pregnancy rate correlate with gene expression of vascular endothelial growth factor

Endometriosis as a detrimental condition for granulosa cell steroidogenesis and development: From molecular alterations to clinical impact

Endometriosis is an estrogen-dependent chronic inflammatory condition that affects women in their reproductive period. Alterations in ovarian follicle morphology and function have been documented in affected women. The local intrafollicular environment has been as well examined by various groups. In the present review, we aimed to summarize the molecular evidence supporting the idea that endometriosis can negatively influence growth, steroidogenesis and the function of the granulosa cells (GCs). Reduced P450 aromatase expression, increased intracellular ROS generation and altered WNT signaling characterize the GCs of women with endometriosis. Clear evidence for an increased level of GC apoptosis has been provided in association with the downregulation of pro-survival factors. Other potentially negative effects include decreased progesterone production, locally decreased AMH production and lower inflammatory cytokine expression, although these have been only partially clarified. The possibility that endometriosis per se may influence IVF clinical results as a consequence of the detrimental impact on the local intrafollicular environment is also discussed.

Endostatin Gene Therapy for Endometriosis in Rats

Objective:

Endostatin gene therapy for endometriosis was studied in an experimental autotransplantation model in rats.

Methods:

Endometriotic lesions were transfected by intralesional injection of the plasmid lipofectamine-endostatinpBud (group 1), lipofectamine-pBud (empty vector; group 2) or phosphatebuffered saline (group 3). Endostatin mRNA and protein levels in lesions were evaluated by quantitative real-time reverse transcription-polymerase chain reaction and Western blot analysis. Endostatin and vascular endothelial growth factor (VEGF) protein levels in serum, and microvessel density (MVD) and matrix metalloproteinase (MMP)-2 protein levels in endometriotic lesions, were also determined.

Results:

Lipofectamine- endostatin-pBud injection increased endostatin mRNA and protein levels in lesions. Lesions were significantly smaller, and serum VEGF levels significantly lower, in group 1 versus controls. Serum VEGF was significantly and negatively correlated with serum endostatin. In group 1, MMP-2 levels and MVD were significantly lower versus controls. MMP-2 level was negatively correlated with endostatin.

Conclusions:

Gene therapy with endostatin appears to be an effective treatment for endometriosis. Restoration of endostatin gene expression by gene transfer in vivo might be a potential gene therapy approach for human endometriosis.

Relations between steroids and AMH: impact of basal and intrafollicular steroids to AMH ratios on oocyte yield and maturation rate in women with or without polycystic ovary undergoing in vitro fertilization

OBJECTIVE

This study sought to determine the relationships between serum or intrafollicular ovarian steroids and anti-mullerian hormone (AMH) and to predict impact of steroids to AMH ratios on oocyte quantity and metaphase II (MII) oocyte rate in normo-ovulatory (control) and polycystic ovary syndrome (PCOS) patients.

DESIGN

Prospective study.

SETTING

University hospital and research center.

PATIENTS

Thirty-two patients with PCOS and 37 controls undergoing IVF-ET.

METHODS

Serum (day 3) and follicular fluid (FF) from more than one follicle ≥ 17 mm on the day of oocyte retrieval were collected from each patients.

MAIN OUTCOME MEASURES

Serum or follicular fluid steroids, AMH, retrieved oocytes number and maturation rate.

RESULTS

In control group, intrafollicular AMH levels were positively related to P4 and T levels (p = .002, p = .011, respectively). Multiple linear regression analysis showed serum basal AMH and T levels as independent positive predictors while T/AMH ratio and intrafollicular AMH were negative predictors for both retrieved and MII oocyte number. The presence of PCOS and intrafollicular P4/AMH ratio revealed as important negative factors influencing oocyte maturation rate.

CONCLUSIONS

Serum basal T, AMH as well as their ratio and intrafollicular P4/AMH ratio may be used as predictors for retrieved oocyte number and their nuclear maturation rate, respectively.

A unique human chorionic gonadotropin antagonist suppresses ovarian hyperstimulation syndrome in rats

Ovarian hyperstimulation syndrome (OHSS) is a complication of in vitro fertilization associated with physiological changes after hCG administration to induce final oocyte maturation. It presents as widespread increases in vascular permeability and, in rare cases, results in cycle cancellation, multi-organ dysfunction, and pregnancy termination. These physiological changes are due primarily to activation of the vascular endothelial growth factor (VEGF) system in response to exogenous human chorionic gonadotropin (hCG). An hCG antagonist (hCG-Ant) could attenuate these effects by competitively binding to the LH/CG receptor, thereby blocking LH activity in vivo. We expressed a form of hCG that lacks three of its four N-linked glycosylation sites and tested its efficacy as an antagonist. The hCG-Ant binds the LH receptor with an affinity similar to native hCG and inhibits cAMP response in vitro. In a rat model for ovarian stimulation, hCG-Ant dramatically reduces ovulation and steroid hormone production. In a well-established rat OHSS model, vascular permeability and vascular endothelial growth factor (VEGF) expression are dramatically reduced after hCG-Ant treatment. Finally, hCG-Ant does not appear to alter blastocyst development when given after hCG in mice. These studies demonstrate that removing specific glycosylation sites on native hCG can produce an hCG-Ant that is capable of binding without activating the LH receptor and blocking the actions of hCG. Thus hCG-Ant will be investigated as a potential therapy for OHSS.

VEGF system expression in different stages of estrous cycle in the corpus luteum of non-treated and superovulated water buffalo

Water buffaloes are easily adaptable animals, whose raising and economical exploitation have been growing in the last three decades all over the world. Hyperstimulation of ovarian function in this species is a common technique aiming to improve reproductive performance. Superovulatory treatment affects corpus luteum (CL) function, which is highly correlated to angiogenic process. The aim of this study was therefore to assess the temporal protein and mRNA expression of VEGF and its receptors in the CL of non-treated and superovulated buffaloes. For that purpose blood samples and CL from 36 healthy (30 untreated, groups 1-5, and 6 superovulated, group 6) non-pregnant buffaloes were collected and the samples were divided into 6 groups according to the age of CL. Plasma samples were submitted to RIA to measure progesterone concentration and CL were subjected to immunohistochemistry and real time PCR for VEGF (vascular endothelial growth factor), Flt-1 (fms-like tyrosine kinase receptor 1) and KDR (kinase insert domain containing region). The VEGF system protein and mRNA expression during CL life span of untreated animals showed a specific time-dependent profile, although protein did not always reflect mRNA concentrations. VEGF expression in luteal cells was high correlated to plasma progesterone levels. Superovulated CL showed a significant increase of the VEGF-system protein and a significant decrease of mRNA expression compared to untreated animals in the same stage of the oestrous cycle. We conclude that VEGF, Flt-1 and KDR protein and mRNA expression in buffalo CL is dependent of estrous cycle stage and superovulatory treatment is able to increase the translation rate of this system.

Significance of ovarian macrophages in the follicular aspirates from ART patients

PURPOSE

To evaluate the percentages of macrophages present in granulosa cells (GC) cultures from patients with different responses to the hyperstimulation, in relation to the percentages of apoptotic cells (ApC), as well as to the release of cytokines.

METHODS

We studied 42 patients: 12 Hyporesponders, (with < or =4 follicles), 15 Normoresponders, (5-14 follicles), and 15 Hyperresponders, (> or =15 follicles). In GC cultures percentages of macrophages and ApC were counted and, in the conditioned media, cytokines were measured.

RESULTS

Percentages of macrophages were significantly higher in GC cultures from Hyporesponders compared with Hyperresponders patients. Also, the percentages of ApC cells were the highest in Hyporesponders. On the contrary, cytokines concentrations were the lowest in this group.

CONCLUSIONS

The low ovarian response is probably due to the decreased angiogenesis, which in turn produces increased apoptosis and decreased production of cytokines. The increased percentage of macrophages could be related to increased frequency of apoptotic cells.

Comparison of follicular fluid IGF-I, IGF-II, IGFBP-3, IGFBP-4 and PAPP-A concentrations and their ratios between GnRH agonist and GnRH antagonist protocols for controlled ovarian stimulation in IVF-embryo transfer patients

BACKGROUND

Insulin-like growth factors (IGF) and their binding proteins (IGFBP) play a major role in the autocrine and paracrine regulation of folliculogenesis. This is the first study that has compared follicular fluid (FF) IGF-I, IGF-II, IGFBP-3, IGFBP-4 and pregnancy-associated plasma protein (PAPP)-A concentrations, and their ratios, to investigate whether there was any difference in the intrafollicular microenvironment between the GnRH agonist (GnRHa) and antagonist (GnRHant) protocols for controlled ovarian stimulation (COS).

METHODS

A total of 68 IVF cycles were included in this study; two groups were studied: GnRHa long protocol group (n = 36) and the flexible GnRHant multiple-dose protocol group (n = 32). FF was obtained from dominant follicles during oocyte retrieval and stored at -70 degrees C until assayed. IGF-I, IGF-II and IGFBP-3 concentrations were measured by radioimmunoassay and IGFBP-4 and PAPP-A by enzyme-linked immunosorbent assay.

RESULTS

The duration of COS was significantly longer, and total dose of gonadotrophins used, serum estradiol (E(2)) levels on hCG day and the number of oocytes retrieved were significantly higher in the GnRHa long protocol group. The concentrations of FF IGF-II and IGFBP-4 were significantly higher, and the ratio of IGF-I/IGFBP-4 was significantly lower in the GnRHa long protocol group. Serum E(2) levels per mature follicle were not different between the two groups.

CONCLUSIONS

Our data may indicate a difference of intrafollicular microenvironment between cycles using GnRHa long protocols and those using GnRHant protocols. However, the difference in microenvironment does not appear to result in a difference in clinical outcome.

Follicular fluid vascular endothelial growth factor concentrations are increased during GnRH antagonist/FSH ovarian stimulation cycles

BACKGROUND

The aim of this study was to investigate the effect of GnRH antagonists (GnRH-ant) on follicular fluid vascular endothelial growth factor (FF VEGF).

METHODS

Sixty women undergoing assisted reproduction were randomised (computer-generated randomisation list) and assigned to two different GnRH analogue regimens: GnRH agonist (GnRH-a) (Group A; n = 30) and GnRH-ant (Group B; n = 30).

RESULTS

Mean (+/-S.D.) FF VEGF concentrations were 1598+/-612 pg/mL and 2906+/-1558 pg/mL for Groups A and B, respectively (p < 0.001). In the women treated with GnRH-ant, we found a statistically significant reduction in serum LH levels (1.72+/-0.74 IU/L in Group A versus 0.93+/-0.43 IU/L in Group B, p < 0.001), in serum oestradiol (E2) levels (1562.1+/-410.7 pg/mL in Group A versus 1214.67+/-779.9 pg/mL in Group B, p < 0.05), in FF E2 levels (1146+/-593 ng/mL in Group A versus 621+/-435 ng/mL in Group B, p < 0.05), and in FF androstenedione levels (136+/-55 ng/mL in Group A versus 78+/-31 ng/mL in Group B, p < 0.001), as well as a reduction in the number of pregnancies, though not statistically significant (23.3% in Group A versus 16.6% in Group B).

CONCLUSION

The increase in FF VEGF levels in women treated with GnRH-ant might be explained by a suppression of LH and E2 levels.

Vascular endothelial growth factor in the plasma, follicular fluid and granulosa cells of women with endometriosis submitted to in vitro fertilization--a pilot study

Vascular endothelial growth factor (VEGF), a potent angiogenic factor that is altered in endometriosis, supports the immunological mechanism involved in this disease. The aim of the present study was to assess VEGF concentration in the plasma, follicular fluid (FF) and culture medium (CM) of granulosa cells from patients with endometriosis submitted to in vitro fertilization (IVF). A case-control study was conducted on 14 patients with endometriosis and 14 women without endometriosis submitted to IVF. Peripheral blood samples were collected before and after administration of human chorionic gonadotropin (hCG), in addition to FF and CM samples. Plasma VEGF levels increased after hCG administration in women with endometriosis and in controls, but were significant only in controls. VEGF levels were lower in FF but were significantly increased in the CM of patients with endometriosis. There was no correlation between VEGF and age, response to ovarian stimulation, oocyte or embryo quality, and pregnancy result. The increase of VEGF levels after hCG in both groups demonstrated a positive effect of this hormone on VEGF. VEGF in the FF and CM presented opposite results in endometriosis, suggesting that granulosa cells may show a different behavior in vivo and in vitro.

Influence of severe endometriosis on gene expression of vascular endothelial growth factor and interleukin-6 in granulosa cells from patients undergoing controlled ovarian hyperstimulation for in vitro fertilization-embryo transfer

OBJECTIVE

To evaluate how endometriosis affects expression of vascular endothelial growth factor (VEGF) and interleukin-6 (IL-6) in granulosa cells.

DESIGN

Prospective study.

SETTING

IVF-ET program at Osaka Medical College.

PATIENT(S)

Seventeen patients with revised American Fertility Society stage IV endometriosis and 17 patients with tubal infertility and no endometriosis.

INTERVENTION(S)

Granulosa cells obtained at oocyte retrieval were examined for VEGF and IL-6 gene expression.

MAIN OUTCOME MEASURE(S)

Serum E(2) and P levels at hCG administration, number of oocytes, fertilization rate, high-quality embryo rate, and pregnancy rate, and expression of VEGF and IL-6 genes.

RESULT(S)

Total hMG and FSH levels were statistically significantly higher in patients with endometriosis; however, the number of retrieved oocytes and the fertilization rate were lower compared with patients with tubal infertility. Serum E(2) levels and expression of VEGF in patients with tubal infertility were statistically significantly higher than those in patients with endometriosis. Interleukin-6 gene expression did not differ between the groups.

CONCLUSION(S)

In severe endometriosis, lower VEGF gene expression in granulosa cells may adversely affect oocyte development and maturation.

Time- and dose-dependent differential upregulation of three genes by 17 beta-estradiol in endothelial cells

The purpose of this study was to identify genetic targets in the vasculature for estrogen by profiling genes expressed in female human aortic endothelial cells exposed to various doses of 17 beta-estradiol at differing concentrations and for differing periods of time. Our approach employed a RT-PCR-based cloning strategy of DNA differential display analysis, with differential expression verified by semiquantitative PCR performed with gene-specific primers. A significant increase in mRNA expression in response to 17 beta-estradiol was observed for the following three genes: aldose reductase (3.4-fold), caspase homologue-alpha protein (4.2-fold), and plasminogen activator inhibitor-1 intron e (2.3-fold). For all three upregulated genes, estradiol-induced upregulation occurred with a similar time course and temporally clustered to the first 24 h after hormone treatment. In addition, the effect of estradiol dose on gene expression was consistent and occurred at physiological concentrations. Our results describe previously uncharacterized estradiol-sensitive time- and dose-dependent regulation of genes with potential importance to vascular function in human endothelial cells.

Relationship of ovarian stimulation response with vascular endothelial growth factor and degree of granulosa cell apoptosis

BACKGROUND

The aim of this study was to evaluate the concentration of vascular endothelial growth factor (VEGF) in follicular fluid and in granulosa cell cultures in relation to the degree of apoptosis in granulosa cells from patients with different types of ovarian response to controlled ovarian hyperstimulation.

METHODS

We studied 30 women who underwent controlled ovarian hyperstimulation and oocyte retrieval. Group A comprised patients with 1-4 follicles (n = 10), group B patients with 5-14 follicles (n = 10) and group C patients with >15 follicles (n = 10).

RESULTS

Mean (+/-SD) VEGF concentrations in follicular fluid were 1232 +/- 209, 813 +/- 198 and 396 +/- 103 pg/ml for groups A, B and C respectively (P > 0.01). Concentrations of VEGF in granulosa cell supernatant were 684 +/- 316, 1101 +/- 295 and 1596 +/- 227 pg/ml respectively (P < 0.05). Percentages of apoptotic cells in granulosa cells culture was 55.02 +/- 7.5, 23.98 +/- 4.4 and 14.2 +/- 2.3% respectively (A versus B, P < 0.01, A versus C, P < 0.006, B versus C, NS).

CONCLUSIONS

Our findings showed that in patients with decreased ovarian response to controlled ovarian hyperstimulation, follicular fluid VEGF concentration is elevated, the concentration from granulosa cells culture supernatant is decreased and the percentage of apoptotic granulosa cells is increased, while opposite findings occurred in patients with normal or hyper-responses.

Poor responder-high responder: the importance of soluble vascular endothelial growth factor receptor 1 in ovarian stimulation protocols

This study was designed to detect vascular endothelial growth factor (VEGF) and its soluble receptor (sVEGFR-1) in follicular fluid specimens and to evaluate the importance of sVEGFR-1 with respect to ovarian response to gonadotrophin stimulation. A total of 69 patients was treated for IVF with recombinant human follicle stimulating hormone (FSH). Concentrations of VEGF and sVEGFR-1 were quantified in follicular fluids from oocyte retrievals. Patients were designated to three groups with respect to the number of harvested oocytes: group A, 1-5 oocytes; group B, 6-10 oocytes; group C, >10 oocytes. In group A, 1133 +/- 870 pg VEGF/ml follicular fluid per oocyte were quantified, in group B 426 +/- 262 pg VEGF/ml per oocyte, and in group C 274 +/- 179 pg VEGF/ml per oocyte. Soluble VEGFR-1 concentrations resulted in 1200 +/- 523 pg/ml follicular fluid per oocyte in group A, 255 +/- 193 pg/ml per oocyte in group B, and 79 +/- 69 pg/ml per oocyte in group C. No free sVEGFR-1 could be detected in any follicular fluid. An index to estimate the biological activity of VEGF by dividing VEGF/sVEGFR-1 revealed an increasing availability of VEGF with higher ovarian response to gonadotrophin therapy. In group A this index was 1.03, in group B 1.71, and in group C 3.21. A delicate balance between VEGF and sVEGFR-1 is necessary to allow an adequate ovarian reaction to gonadotrophin therapy. Excess of bio-active VEGF increases the risk for ovarian hyperstimulation syndrome. Excess of sVEGFR-1 results in poor response and goes in parallel with reduced chances for conception.

Vascular endothelial growth factor in reproductive biology

The critical role of angiogenesis in embryology and tumor biology has been recognized for more than 20 years. However, the fact that neovascularization is essential to processes in mammalian female reproduction has only recently been appreciated widely. In this review we focus on a single angiogenic growth factor, vascular endothelial growth factor. As scientists have discovered in many aspects of cell biology, multiple and redundant signaling pathways have evolved in nature, presumably to protect essential biological functions from inactivating diseases or mutations. Despite this redundancy, some factors are of hierarchical importance. Vascular endothelial growth factor appears to be such a factor in the regulation of angiogenesis.