Administration of moderate and high doses of gonadotropins to female rats increases ovarian vascular endothelial growth factor (VEGF) and VEGF receptor-2 expression that is associated to vascular hyperpermeability

Ginkgo biloba extract 761 reduces vascular permeability of the ovary and improves the symptom of ovarian hyperstimulation syndrome in a rat model

AIMS

Ginkgo biloba extract (EGb) has been widely applied in the treatment of cerebrovascular and neurological diseases. However, the effect of EGb761 on ovarian hyperstimulation syndrome (OHSS), a vascular disorder and life-threatening complication of in vitro fertilization and intracytoplasmic sperm injection therapy (IVF/ICSI), has not been evaluated.

MATERIALS AND METHODS

Forty female Wistar rats aged 22-days old (D22) were divided into eight groups: Control rats received intraperitoneal injection of saline for five consecutive days (D22-D26); OHSS model group received 10 IU equine chorionic gonadotropin (eCG) for four consecutive days (D22-D25) and 30 IU of human chorionic gonadotropin (hCG) on the 5th day (D26); Prophylactic treatment group received three doses of EGb761 (50, 100, and 200 mg/kg/day) 1 h before injection of eCG (hCG) for seven consecutive days; Therapeutic treatment group received three doses of EGb761 (50, 100, and 200 mg/kg/day) 48 h after injection of eCG (hCG) for seven consecutive days.

RESULTS

All three doses of EGb761 therapeutic medication significantly reduced ovarian mass index of OHSS model rats (p ≤ .01). Furthermore, therapeutic treatment group exhibited improved vascular permeability, decreased estradiol and progesterone levels, lower corpus luteum, and higher follicle numbers compared with the OHSS model. Elevated protein expression of vascular endothelial growth factor (VEGF) and VEGF receptor (VEGFR) in both ovary and kidney of the OHSS model was restrained by EGb761 therapeutic treatment.

CONCLUSIONS

EGb761 therapeutic medication decreases vascular permeability in OHSS rat model by inhibiting VEGF and VEGFR expression, which may contribute to the treatment of OHSS.

Ginkgo biloba extract 761 reduces vascular permeability of the ovary and improves the symptom of ovarian hyperstimulation syndrome in a rat model

AIMS

Ginkgo biloba extract (EGb) has been widely applied in the treatment of cerebrovascular and neurological diseases. However, the effect of EGb761 on ovarian hyperstimulation syndrome (OHSS), a vascular disorder and life-threatening complication of In Vitro Fertilization and Intracytoplasmic Sperm Injection therapy (IVF/ICSI), has not been evaluated.

MATERIALS AND METHODS

Forty female Wistar rats aged 22-days old (D22) were divided into eight groups: Control rats received intraperitoneal injection of saline for 5 consecutive days (D22-D26); OHSS model group received 10 IU equine chorionic gonadotropin (eCG) for 4 consecutive days (D22-D25) and 30 IU of human chorionic gonadotropin (hCG) on the 5th day (D26); Prophylactic treatment group received three doses of EGb761 (50, 100, and 200 mg/kg/d) one hour before injection of eCG (hCG) for 7 consecutive days; Therapeutic treatment group received three doses of EGb761 (50, 100, and 200 mg/kg/d) 48 h after injection of eCG (hCG) for 7 consecutive days.

RESULTS

All three doses of EGb761 therapeutic medication significantly reduced ovarian mass index in the OHSS model (p ≤ .01). Further, the therapeutic treatment group exhibited improved vascular permeability, decreased estradiol and progesterone levels, lower corpus luteum, and higher follicle numbers compared with the OHSS model. Elevated protein expression of vascular endothelial growth factor (VEGF) and VEGF receptor (VEGFR) in both ovary and kidney of the OHSS model was restrained by EGb761 therapeutic treatment.

CONCLUSIONS

EGb761 therapeutic medication decreases vascular permeability in OHSS rat model by inhibiting VEGF and VEGFR expression, which may contribute to the treatment of OHSS.

Tie1 contributes to the development of ovarian hyperstimulation syndrome under the regulation of EGR1 in granulosa cells

The expression of tyrosine kinase with immunoglobulin-like and epidermal growth factor-like domains 1 (Tie1), a transmembrane protein expressed almost exclusively by endothelial cells, has been reported in granulosa cells. However, its significance in ovarian hyperstimulation syndrome (OHSS), which can occur after the injection of gonadotropins in infertile women undergoing controlled ovarian stimulation, is unknown. Here, we report significantly increased Tie1 and vascular endothelial growth factor (VEGF) expression in cultured granulosa cells from OHSS patients, as well as ovaries from rats with experimentally established OHSS, compared to controls, with the levels of both proteins also increasing in granulosa and SVOG cells (a nontumorigenic human granulosa-lutein cell line) treated with an acute dose of human chorionic gonadotropin (hCG). Tie1 silencing abolished the hCG-induced VEGF level in SVOG cells and attenuated the progression of OHSS in rats, as determined by histological analysis. Further studies in SVOG cells revealed that the hCG-induced upregulation of Tie1 expression involved the phosphoinositide 3-kinase/protein kinase B signaling pathway. We also report that early growth response protein 1 (EGR1), whose expression was also upregulated by hCG, bound directly to the Tie1 promoter and activated its transcription. Taken together, our results indicate that Tie1 may be a therapeutic target in cases of moderate-to-severe OHSS. Further studies are needed to address its clinical relevance.

Prediction of severe ovarian hyperstimulation syndrome in women undergoing in vitro fertilization using estradiol levels, collected ova, and number of follicles

Objective

Our objective was to determine whether estradiol (E2) levels (Day 3 and fold change to Day 10), antral follicle count (AFC), and number of ova collected could predict ovarian hyperstimulation syndrome (OHSS) and culdocentesis intervention.

Methods

We conducted a retrospective review of patient charts between January 2008 and December 2017. OHSS was defined using American Society for Reproductive Medicine criteria. Predictability was evaluated by measuring the area under the receiver operating characteristic curve (AUC).

Results

The cohort included 319 women (166 controls, 153 OHSS, of whom 54 had severe OHSS). The OHSS group had higher E2_Day 3 (249 ± 177 vs. 150 ± 230 ng/L), E2_FoldChange (32.2 ± 29.1 vs. 20.1 ± 23.8), AFC (18.2 ± 9.1 vs. 11.6 ± 8.3), and number of ova collected (21.1 ± 9.0 vs. 10.1 ± 6.5). E2_Day 3 (AUC = 0.76, 95%CI: 0.71–0.82), E2_FoldChange (AUC = 0.71, 95%CI: 0.65–0.77), AFC (AUC = 0.75, 95%CI: 0.70–0.81), and number of ova collected (AUC = 0.85, 95%CI: 0.81–0.89) were predictive for OHSS. All variables were predictive for culdocentesis intervention (E2_Day 3: AUC = 0.63, 95%CI: 0.55–0.70; E2_FoldChange: AUC = 0.63, 95%CI: 0.55–0.71; AFC: AUC = 0.74, 95%CI: 0.68–0.80; number of ova collected: AUC = 0.80, 95%CI: 0.75–0.85).

Conclusions

Day 3 E2 levels and number of ova collected predict patients who could develop OHSS and may require culdocentesis.

Gonadotropin levels at the start of ovarian stimulation predict normal fertilization after hCG re-trigger in GnRH antagonist cycles

PURPOSE

To assess the appropriateness of human chorionic gonadotropin (hCG) re-trigger in poor responders to gonadotropin-releasing hormone agonist (GnRHa) trigger in controlled ovarian stimulation (COS) cycles.

METHODS

The 2251 cycles in 2251 patients triggered with GnRHa for oocyte stimulation, with or without requiring hCG re-trigger between 2013 and 2018, were retrospectively analyzed to compare gonadotropin levels at the start of COS and the rate of normal fertilization between the re-trigger and non-re-trigger group. Furthermore, patients in the re-trigger group were stratified by the rate of normal fertilization (good: ≥60% or poor: <60%) to compare patient demographics, hormone profiles, and clinical outcome between the subgroups.

RESULTS

In the re-trigger group, FSH and LH levels at the start of COS were significantly lower in the good fertilization group than in the poor fertilization group (P < .01). Receiver operating characteristic curves identified cutoff values of the FSH and LH levels of 1.30 and 0.35 mIU/mL, respectively, for predicting ≥60% normal fertilization.

CONCLUSION

Gonadotropin levels at the start of COS are predictors of response to GnRHa trigger and hCG re-trigger necessity, and may serve as indicators to help clinicians appropriately choose hCG re-trigger rather than abandoning the cycles or continuing the first oocyte aspiration attempt.

Successful reversal of ovarian hyperstimulation syndrome in a mouse model by rapamycin, an mTOR pathway inhibitor

Ovarian hyperstimulation syndrome (OHSS) is a potentially life-threatening, iatrogenic complication of ovarian stimulation in assisted reproduction technology. This complex syndrome is characterised by enlarged ovaries with multiple corpora luteum, elevated sex steroid hormones in serum and increased capillary permeability. Until now, the pathogenesis of OHSS remains obscure, and no absolute strategy can fully prevent OHSS without any side effect on ovulation and clinical pregnancy. Using cultured human or mouse granulosa cells, our study revealed the time-dependent activation of the mTOR signaling pathway after human chorionic gonadotropin (hCG) treatment. The involvement of the mTOR signaling pathway was also observed in the development of OHSS in a mouse model. Selectively inhibiting mTOR signals by only two injections of rapamycin (2 mg/kg body weight), before or just after hCG treatment, significantly reduced vascular leakage and the severity of OHSS symptoms. Although ovarian angiogenesis was significantly inhibited, rapamycin could not decrease the elevated levels of vascular endothelial growth factor, IL-6 and IL-11 in OHSS ovaries. Further study showed the functional roles of the mTOR signaling pathway in the hyperstimulation-induced ovarian extracellular matrix remodeling as the expression of α2M, a broad proteolytic inhibitor in both ovary and serum, was dramatically decreased after rapamycin treatment. Since a single injection of rapamycin during superovulation had no side effects on ovulation and early embryonic development, we propose rapamycin may be a good candidate to lower and prevent the risk of OHSS in the future.

HORMONAL SUPPLEMENTATION TRIGGERING CHOROIDAL NEOVASCULARIZATION IN HEALTHY YOUNG FEMALES

PURPOSE

To report three cases of choroidal neovascularization after hormonal treatment for ovarian stimulation during a fertility therapy.

METHODS

A comprehensive ophthalmic examination was performed in all cases including best-corrected visual acuity, color fundus examination, fluorescein angiography, and optical coherence tomography.

RESULTS

Three females in their thirties developed unilateral acuity vision loss and metamorphopsia. They all were undergoing hormonal supplementation for ovarian stimulation with gonadotropins at the moment of presentation. Intravitreal therapy with ranibizumab was used; all cases showed a significant functional and anatomical improvement.

DISCUSSION

Hormonal supplementation for fertility therapy is a common procedure that may be associated with the development of choroidal neovascularization in healthy young females. Further studies should be performed to evaluate this association, but both ophthalmologist and gynecologist should be aware of this potential complication.

Rare genetic variants potentially involved in ovarian hyperstimulation syndrome

PURPOSE

We aim to investigate whether there is a genetic predisposition in women who developed ovarian hyperstimulation syndrome (OHSS) after GnRH antagonist protocol with GnRH agonist trigger and freeze-all approach.

METHODS

Four patients with OHSS after GnRH agonist trigger and freeze-all approach were gathered from the worldwide patient population. These patients were analyzed through Whole Exome Sequencing. In this study known causes of OHSS were investigated and new causes present in at least two individuals were searched for.

RESULTS

In the first part of the study, we evaluated the presence of mutations in genes already known to be involved in OHSS. In PGR and TP53, heterozygous alterations were detected. PGR is predicted to be involved in progesterone resistance with a recessive inheritance pattern and is, therefore, not considered as being causal. The consequences of the variant detected in TP53 currently remain unknown. In part 2 of the study, we assessed the clinical significance of variants in genes previously not linked to OHSS. We especially focused on genes with variants present in ≥ 2 patients. Two patients have variants in the FLT4 gene. Mutations in this gene are linked to hereditary lymphedema, but no link to OHSS has been described.

CONCLUSIONS

Defining a genetic predisposition for OHSS is essential in view of prevention. In this study, a potential link between the FLT4 gene and OHSS has been suggested. Future functional studies are essential to define a more precise involvement of the detected variants in the development of OHSS.

The superovulated environment, independent of embryo vitrification, results in low birthweight in a mouse model

Epidemiological studies suggest that babies born following in vitro fertilization (IVF) and fresh embryo transfer are of lower birthweight than babies born following frozen embryo transfer, although the mechanism responsible for this phenotype is not known. We developed a novel mouse model that isolates the independent effects of embryo freezing and the superovulated environment, which cannot be performed in humans. We transferred blastocysts that had been vitrified and warmed, mixed with with fresh blastocysts, into individual pseudopregnant recipients produced by either natural mating or mating following injection with equine chorionic gonadotropin and human chorionic gonadotropin and hCG (superovulation). We found that superovulation of the recipient dams led to significantly lower fetal weight at term while blastocyst vitrification had no significant effect on fetal weight (1.43 ± 0.24 g fresh-natural, 1.30 ± 0.28 g vitrified-natural vs. 1.09 ± 0.20 fresh-superovulated, 0.93 ± 0.23 g vitrified-superovulated, P < 0.0001). Doppler ultrasound revealed increased median umbilical artery resistance in the placentae of near-term dams exposed to superovulation compared to naturally mated dams (0.927 vs 0.904, P = 0.02). Additionally, placental microvascular density was lower in superovulated compared to naturally mated dams (1.24 × 10-3 vessel/micron vs 1.46 × 10-3 vessels/micron, P = 0.046). Gene expression profiling suggested alterations in fetal genes involved in glucorticoid regulation. These results suggest a potential mechanism for altered birthweight following superovulation in our model and may have implications for human IVF.

Gonadotrophin stimulation in IVF alters the immune cell profile in follicular fluid and the cytokine concentrations in follicular fluid and serum

Study question

Are the immune cell profiles and the cytokine concentrations in follicular fluid (FF) and serum at the preovulatory stage different in conventional exogenous gonadotrophin stimulated IVF (c-IVF) compared with natural cycle IVF (NC-IVF)?

Summary answer

The cell counts of CD45+ leucocytes and T cell subpopulations and the cytokine concentrations in FF and serum are different in c-IVF compared to NC-IVF.

What is known already

FF-derived cells are heterogeneous. Immune cells are involved in intra-ovarian processes and cytokines are required for normal follicular development. Gonadotrophins stimulate the regulatory intrafollicular system and influence the local distribution of immune cells and the intrafollicular release of cytokines. Administration of exogenous gonadotrophins may have a significant effect on this local regulatory system, which then in turn could influence oocyte quality.

Study design, size, duration

The study included 105 patients, 69 undergoing c-IVF and 36 undergoing NC-IVF. c-IVF was performed by exogenous ovarian stimulation with hMG and GnRH antagonists.

Participants/materials, setting, methods

FF samples were collected from the first dominant follicle in c-IVF without pooling and from single leading preovulatory follicles in NC-IVF. Three different approaches were used to analyze FF samples: (i) microscopic investigation of CD45+ leucocytes, (ii) fluorescence-activated cell sorting to determine CD19+ B cells and CD3+ T cells including T cell subpopulations (CD4+, CD8+), and (iii) evaluation of tumour necrosis factor-alpha (TNF-α), interferon-gamma (INF-γ), interleukins (IL)-2, -6, -8, -10 and vascular endothelial growth factor (VEGF) levels in matched FF and serum samples using the Bio-Plex® platform.

Main results and the role of chance

FF obtained from c-IVF contained proportionally more CD45+ leucocytes (P = 0.0384), but fewer CD8+ cytotoxic T cells than FF from NC-IVF. CD3+ T lymphocytes were the most common type of lymphocytes, and the number thereof was comparable in the two study groups. In c-IVF, serum VEGF levels were higher (P = 0.007) than in NC-IVF while FF contained marginally decreased concentrations of IL-8 in c-IVF in comparison to NC-IVF. The cytokine concentration gradient between FF and serum in c-IVF was 10-fold for IL-8 and 8-fold for VEGF and thereby markedly lower than in NC-IVF, where the differences were 32-fold and 30-fold, respectively. Strong positive correlations were determined between FF- IL-10 and FF- VEGF in c-IVF (r = 0.85, P < 0.0001) and in NC-IVF (r = 0.81, P < 0.0001).

Large scale data

N/A.

Limitations, reasons for caution

The ovulation of NC-IVF follicles was induced by the exogenous administration of hCG, which means that the environment did not fully correspond to the physiological situation.

Wider implications of the findings

The differences in the immune profile and the cytokine concentrations in c-IVF and NC-IVF follicles support the hypothesis that conventional ovarian stimulation affects indirectly and heterogeneously the intrafollicular milieu, and thereby possibly affects the oocyte quality and the IVF outcome. However, further studies are needed to confirm our findings and to refine stimulation protocols in the context of optimizing the intrafollicular environment during oocyte maturation.

Study funding/competing interest(s)

The study was supported by a research grant from IBSA Institut Biochimique SA and MSD Merck Sharp & Dohme GmbH. The authors are clinically involved in low dose mono-follicular stimulation and IVF-therapies, using gonadotrophins from all gonadotrophins distributors on the Swiss market, including Institut Biochimique SA and MSD Merck Sharp & Dohme GmbH.

Comparison between resveratrol and cabergoline in preventing ovarian hyperstimulation syndrome in a rat model

OBJECTIVE

The aim of this study is to investigate the effects of resveratrol in a rat model of ovarian hyperstimulation syndrome (OHSS) and compare with cabergoline.

DESIGN

Randomized controlled, animal study.

ANIMAL(S)

Female Wistar rats.

MATERIAL AND METHODS

A rat OHSS model was used to investigate the effects of resveratrol compare with cabergoline administration for preventing OHSS. Body weight, ovary weight, diameter, vascular permeability (VP), vascular endothelial growth factor (VEGF), cyclooxygenase-2 (COX-2) expression (immunohistochemistry), and serum estradiol (E2) levels were then compared.

RESULTS

The ovarian VEGF concentration was significantly increased in the OHSS Groups (Groups 3-5) compared with the control groups (1 and 2). But vascular permeability, VEGF, and COX-2 expressions were reduced in animals treated with the resveratrol group compared with the cabergoline group (group 5) and the severe OHSS (group 3) group. Blood E2 levels were decreased in group treated with the resveratrol group compared with the cabergoline group (group 5) and severe the OHSS (group 3) group.

CONCLUSION(S)

Our results in a rat model suggest that resveratrol has a beneficial effect on OHSS by reducing the increases in ovarian daimeter, VP, and VEGF expression associated with OHSS. These effects may be mediated by the COX-2 inhibitory capacity of resveratrol.

A potential role of endoplasmic reticulum stress in development of ovarian hyperstimulation syndrome

Vascular endothelial growth factor A (VEGFA) is crucial for ovarian angiogenesis, but its excess production induces ovarian hyperstimulation syndrome (OHSS). The aim of this study was to determine whether endoplasmic reticulum (ER) stress regulates VEGFA expression in granulosa cells, and whether its activation is involved in OHSS development. The expression of the spliced form of X-box-binding protein 1 [XBP1(S)], induced by ER stress, in cumulus cells from OHSS patients was higher than that in cumulus cells from non-OHSS patients. The ER stress inducer tunicamycin increased human chorionic gonadotropin-induced VEGFA production in human granulosa cells through the induction of XBP1(S), and pretreatment with the ER stress inhibitor tauroursodeoxycholic acid (TUDCA) abrogated the effect of tunicamycin. In OHSS model rats, TUDCA administration prevented the OHSS development, reducing ovarian VEGFA production. Our findings suggest ER stress upregulates hCG-induced VEGFA production in granulosa cells, indicating that ER stress might be involved in OHSS development.

Physiologic Course of Female Reproductive Function: A Molecular Look into the Prologue of Life

The genetic, endocrine, and metabolic mechanisms underlying female reproduction are numerous and sophisticated, displaying complex functional evolution throughout a woman's lifetime. This vital course may be systematized in three subsequent stages: prenatal development of ovaries and germ cells up until in utero arrest of follicular growth and the ensuing interim suspension of gonadal function; onset of reproductive maturity through puberty, with reinitiation of both gonadal and adrenal activity; and adult functionality of the ovarian cycle which permits ovulation, a key event in female fertility, and dictates concurrent modifications in the endometrium and other ovarian hormone-sensitive tissues. Indeed, the ultimate goal of this physiologic progression is to achieve ovulation and offer an adequate environment for the installation of gestation, the consummation of female fertility. Strict regulation of these processes is important, as disruptions at any point in this evolution may equate a myriad of endocrine-metabolic disturbances for women and adverse consequences on offspring both during pregnancy and postpartum. This review offers a summary of pivotal aspects concerning the physiologic course of female reproductive function.

Stimulation of LH, FSH, and luteal blood flow by GnRH during the luteal phase in mares

A study was performed on the effect of a single dose per mare of 0 (n = 9), 100 (n = 8), or 300 (n = 9) of GnRH on Day 10 (Day 0 = ovulation) on concentrations of LH, FSH, and progesterone (P4) and blood flow to the CL ovary. Hormone concentration and blood flow measurements were performed at hours 0 (hour of treatment), 0.25, 0.5, 1, 2, 3, 4, and 6. Blood flow was assessed by spectral Doppler ultrasonography for resistance to blood flow in an ovarian artery before entry into the CL ovary. The percentage of the CL with color Doppler signals of blood flow was estimated from videotapes of real-time color Doppler imaging by an operator who was unaware of mare identity, hour, or treatment dose. Concentrations of LH and FSH increased (P < 0.05) at hour 0.25 and decreased (P < 0.05) over hours 1 to 6; P4 concentration was not altered by treatment. Blood flow resistance decreased between hours 0 and 1, but the decrease was greater (P < 0.05) for the 100-μg dose than for the 300-μg dose. The percentage of CL with blood flow signals increased (P < 0.05) between hours 0 and 1 with no significant difference between the 100- and 300-μg doses. The results supported the hypothesis that GnRH increases LH concentration, vascular perfusion of the CL ovary, and CL blood flow during the luteal phase; however, P4 concentration was not affected.

Comparison of montelukast and cabergoline for prevention of ovarian hyperstimulation syndrome: in an experimental rat model

Ovarian hyperstimulation syndrome (OHSS) is a serious iatrogenic complication that can occur during assisted reproductive techniques. The aim of this study is to investigate the effects of the leukotriene receptor antagonist (montelukast) treatment in prevention of OHSS and compare to cabergoline treatment. Twenty-four immature female Wistar rats were assigned to four groups. Group 1 was the control group. In the remaining three groups, OHSS was induced through ovarian stimulation with gonadotropins. No treatment was given to Group 2. Group 3 was administered a low-dose 100 mg/kg cabergoline treatment and Group 4 was received 20 mg/kg montelukast. Body weight, ovarian weight, vasculary permability (VP), peritoneal fluid vascular endothelial growth factor (VEGF) values and VEGF immune-expression were compared between the groups. Both cabergoline and montelukast prevented progression of OHSS compared to the OHSS group. Body weight, ovarian weight, VP, peritoneal fluid VEGF values and VEGF expression were significantly lower in both cabergoline- and montelukast-treated rats than in those not treated OHSS group. In conclusion, montelukast is an effective option for prevention of OHSS, as well as cabergoline. Montelukast may be a new treatment option to prevent and control the OHSS.

Prevention of ovarian hyperstimulation syndrome in a rat model: comparison of the efficacy of tocilizumab with that of ranibizumab, cabergoline, and a gonadotropin-releasing hormone antagonist

The aim of the study is to investigate the effects of the interleukin-6 (IL-6) blocker tocilizumab in a hyperstimulated rat model and compare it with ranibizumab, a gonadotropin-releasing hormone antagonist (GnRHA), and cabergoline. Forty-seven rats were randomly divided into the following seven groups: Group 1: OHS; Group 2: OHS+ GnRHA; Group 3: OHS + ranibizumab; Group 4: OHS + cabergoline; Group 5: OHS + low-dose tocilizumab (TL); Group 6: OHS + high-dose tocilizumab (TH); Group 7: sham. Ovarian weight was significantly lower only in the ranibizumab group than in the OHS group. Estrogen levels were significantly lower in the GnRHA group than in the OHS and the treatment groups. Progesterone levels were significantly lower in the ranibizumab, cabergoline, and TL groups than in the OHS group. Among the treatment groups, corpus luteum counts were lower than in the OHS group. Corpus luteum counts were lowest in the tocilizumab groups. IL-6 intensity was lower in all treatment groups than in the OHS group. In the ranibizumab group IL-6 intensity was the lowest. The TL group did not significantly differ from the GnRHA and cabergoline groups regarding IL-6 expression. Ovarian VEGF expression was significantly lower in all treatment groups. For the TL, ranibizumab, and cabergoline groups VEGF intensity was similar. Tocilizumab may be a new strategy for preventing ovarian hyperstimulation syndrome by inhibition of IL-6.

A potential novel strategy, inhibition of vasopressin-induced VEGF secretion by relcovaptan, for decreasing the incidence of ovarian hyperstimulation syndrome in the hyperstimulated rat model

OBJECTIVE

To investigate the effects of V1A receptor antagonist through inhibition of vasopressin-induced VEGF secretion in an experimental model.

STUDY DESIGN

Thirty rats were randomly divided into five groups. Four groups were given 10IU pregnant mare serum gonadotropin/day (sc) at 8:00-8:30am on days 22-25 of life. They were administered 30IU hCG at 8:00-8:30am on day 26 of life. On days 26 and 27 of life at 8:00am and 4:00pm, (ip) per animal, 50μg/kg/day GnRH antagonist in the GnRH antagonist group, 0.3mg relcovaptan in the high dose relcovaptan group, and 0.15mg relcovaptan in the low dose relcovaptan group were administered. The control group was given the same dosage of 0.9% saline solution (ip) on days 22-26 day of life. The main outcomes were weight gain, ovarian weights, peritoneal fluid VEGF values, corpus luteum count, and atretic follicle count.

RESULTS

Weight gain was highest in the OHSS group; it was almost twice as much in the OHSS group than it was in the control group. Ovarian weights were significantly lower in all treatment groups (p=0.03). There was no statistically significant difference in ovarian weights between the GnRH antagonist and relcovaptan groups (p=0.176). The evaluation of peritoneal fluid VEGF-A levels revealed statistically significant differences between levels in the treatment groups and in the OHSS group (p=0.005). Atretic follicle count in the OHSS group was significantly lower (p=0.048). In all treatment groups, CL counts were prominently lower than they were in the OHSS group (p=0.002).

CONCLUSION

Relcovaptan may be a novel strategy for decreasing risk of OHSS by inhibition of vasopressin-induced VEGF secretion through V1A receptor antagonist.

Blood and lymphatic vasculature in the ovary: development, function and disease

BACKGROUND

The remodelling of the blood vasculature has been the subject of much research while rapid progress in the understanding of the factors controlling lymphangiogenesis in the ovary has only been reported more recently. The ovary undergoes cyclic remodelling throughout each menstrual/estrous cycle. This process requires significant vascular remodelling to supply each new cohort of growing follicles.

METHODS

Literature searches were performed to review studies on the ovarian lymphatic vasculature that described spatial, temporal and functional data in human or animal species. The role of ovarian blood and lymphatic vasculature in the pathogenesis of ovarian disease and dysfunction was also explored.

RESULTS

Research in a number of species including zebrafish, rodents and primates has described the lymphatic vasculature within the remodelling ovary, while recent research in mouse has confirmed hormonal regulation of lymphangiogenic growth factors, their receptors and also a role for the protease, ADAMTS1 in the development of the lymphatic vasculature. With a critical role in the maintenence of fluid homeostasis, the ovarian lymphatic vasculature is important for normal ovarian function and has been linked to syndromes involving ovarian fluid imbalance, including ovarian hyperstimulation syndrome and massive ovarian edema. The lymphatic vasculature has also been heavily implicated in the metastatic cancer process.

CONCLUSION

The spatial and temporal regulation of the ovarian lymphatic vasculature has now been reported in a number of species and the data also implicate the ovarian lymphatic vasculature in ovarian pathologies, including cancer and those linked with use of artificial reproduction technologies.

Metformin decreases the incidence of ovarian hyperstimulation syndrome: an experimental study

Background

In assisted reproduction cycles, gonadotropins are administered to obtain a greater number of oocytes. A majority of patients do not have an adverse response; however, approximately 3-6% develop ovarian hyperstimulation syndrome (OHSS). Metformin reduces the risk of OHSS but little is known about the possible effects and mechanisms of action involved.

Objective

To evaluate whether metformin attenuates some of the ovarian adverse effects caused by OHSS and to study the mechanisms involved.

Material and methods

A rat OHSS model was used to investigate the effects of metformin administration. Ovarian histology and follicle counting were performed in ovarian sections stained with Masson trichrome. Vascular permeability was measured by the release of intravenously injected Evans Blue dye (EB). VEGF levels were measured by commercially immunosorbent assay kit. COX-2 protein expression was evaluated by western blot and NOS levels were analyses by immunohistochemistry.

Results

Animals of the OHSS group showed similar physiopathology characteristics to the human syndrome: increased body weight, elevated progesterone and estradiol levels (P<0.001), increased number of corpora lutea (P<0.001), higher ovarian VEGF levels and vascular permeability (P<0.001 and P<0.01); and treatment with metformin prevented this effect (OHSS+M group; P<0.05). The vasoactive factors: COX-2 and NOS were increased in the ovaries of the OHSS group (P<0.05 and P<0.01) and metformin normalized their expression (P<0.05); suggesting that metformin has a role preventing the increased in vascular permeability caused by the syndrome.

Conclusion

Metformin has a beneficial effect preventing OHSS by reducing the increase in: body weight, circulating progesterone and estradiol and vascular permeability. These effects of metformin are mediated by inhibiting the increased of the vasoactive molecules: VEGF, COX-2 and partially NOS. Molecules that are increased in OHSS and are responsible for a variety of the symptoms related to OHSS.

The effects of bromocriptine on VEGF, kidney function and ovarian hyperstimulation syndrome in in vitro fertilization patients: a pilot study

The aim of this study was to evaluate the effects of bromocriptine on vascular endothelial growth factor (VEGF) levels in serum, kidney function and ovarian hyperstimulation syndrome in women undergoing in vitro fertilization. Twenty-eight women were randomly divided into two groups and were administered daily oral capsules for 14 days, starting on the day of human chorionic gonadotropin (hCG) administration. Group A received 2.0 mg of folic acid, whereas Group B was given 2.5 mg of bromocriptine. Physical exams, pelvic ultrasounds and laboratory evaluations were performed on the day of hCG administration and again 7 days later. No differences in ovarian hyperstimulation syndrome, urine volume, creatinine clearance, urine sodium concentration or serum VEGF levels were found between the two groups. Thus, these results indicate that bromocriptine does not affect blood levels of VEGF, kidney function or the incidence of ovarian hyperstimulation syndrome in high-risk patients subjected to in vitro fertilization.

GnRH analogues in the prevention of ovarian hyperstimulation syndrome

The GnRH analogue (agonist and antagonist GnRH) changed ovarian stimulation. On the one hand, it improved chances of pregnancy to obtain more oocytes and better embryos. This leads to an ovarian hyper-response, which can be complicated by the ovarian hyperstimulation syndrome (OHSS). On the other hand, the GnRH analogue can prevent the incidence of OHSS: GnRH antagonist protocols, GnRH agonist for triggering final oocyte maturation, either together or separately, coasting, and the GnRH analogue may prove useful for avoiding OHSS in high-risk patients. We review these topics in this article.

A case of ovarian hyperstimulation syndrome following a spontaneous complete hydatidiform molar pregnancy

INTRODUCTION

To present a rare case of ovarian hyperstimulation syndrome (OHSS) following a spontaneous complete hydatidiform molar (CHM) pregnancy.

CASE

A 38-year-old woman underwent vacuum curettage for a CHM pregnancy. Seven days later, she was admitted to our hospital with the symptoms of OHSS. Transvaginal ultrasonography demonstrated enlarged multicystic ovaries, marked ascites and large pleural effusions that required abdominocentesis and thoracocentesis, respectively. She was treated with intravenous fluid, exogenous colloid supplementation, prophylaxis for deep vein thrombosis, and drainage of the ascites and bilateral pleural effusions. She recovered by day 14 of admission.

CONCLUSION

OHSS may develop in older women who undergo treatment for CHM pregnancies. Serious complications may develop rapidly and therefore the prompt diagnosis of OHSS is very important.

Co action of CFTR and AQP1 increases permeability of peritoneal epithelial cells on estrogen-induced ovarian hyper stimulation syndrome

Background

Ovarian hyper stimulation syndrome (OHSS) is an iatrogenic complication associated with fertility drugs. It is characterized by increased vascular permeability and substantial fluid shift with accumulation in the body cavity. The pathogenesis of OHSS remains obscure, and no definitive treatments are currently available.

Results

Using western blot and short-circuit current (Isc) techniques, we investigate the potential coactions of analysis in cystic fibrosis transmembrane conductance regulator (CFTR) and aquaporin 1 (AQP1) on the hyper permeability of body cavity peritoneal epithelial cells in the pathogenesis of OHSS. The rats develop OHSS symptoms, with the up regulation of both CFTR and AQP1 expression and enhanced CFTR channel activity in peritoneal epithelial cells, can also be mimicked by administration of estrogen, alone in ovariectomized rats. Administration of progesterone suppresses CFTR activity, OHSS symptoms as well as CFTR and AQP1 expression. Besides, AQP1 inhibitor, HgCl₂, can suppress CFTR channel activity. Therefore, antisera against CFTR or AQP1 to OHSS animals may result in alleviation of the symptom.

Conclusion

This study confirms the coactions of CFTR and AQP1 play a critical role in the development and progression of increased peritoneal epithelial permeability in severe OHSS. These findings may provide grounds for ameliorating assisted reproduction treatment strategy to reduce the risk of OHSS in in vitro fertilization (IVF).

Etiology of OHSS and use of dopamine agonists

Vascular endothelial growth factor is the factor that causes increased capillary permeability and therefore the most serious manifestations of ovarian hyperstimulation syndrome. Dopamine agonists can both prevent and treat ovarian hyperstimulation syndrome by blocking expression of the vascular endothelial growth factor receptor.

Prevention of the onset of ovarian hyperstimulation syndrome (OHSS) in the rat after ovulation induction with a low molecular weight agonist of the LH receptor compared with hCG and rec-LH

Ovarian hyperstimulation syndrome (OHSS) incidentally occurs in controlled ovarian stimulation protocols and is associated with human chorionic gonadotropin (hCG) administration. OHSS is caused by increased vascular permeability (VP) and thought to be mediated by hypersecretion of vascular endothelial growth factor (VEGF) by granulosa cells. Low molecular weight (LMW)-LH agonists have a similar mode of action but a shorter half-life compared with hCG, which could potentially lead to a clinical benefit in reducing the risk for OHSS in controlled ovarian stimulation protocols. The objective of this study is to investigate the role of an orally active LMW-LH agonist in OHSS induction compared with recombinant LH (rec-LH) and hCG. Immature rats were hyperstimulated with pregnant mare serum gonadotropin, and ovulation was induced by hCG, rec-LH or a LMW-LH agonist. The degree of VP was determined by Evans Blue in the abdominal cavity. Ovaries were weighed, and VEGF concentration in the ovary was determined. Pregnant mare serum gonadotropin stimulation followed by single-dose hCG or rec-LH resulted in clear enlargement of the ovaries and increased VP and VEGF levels. However, ovulation induction with a single dose of the LMW-LH agonist did not result in increased VP and VEGF levels, and even multiple dosing to mimic a longer exposure did not induce OHSS symptoms. In conclusion, we demonstrated that the oral LMW-LH agonist did not induce VP in rat, indicative for OHSS, possibly due to reduced VEGF production. If this is translatable to human, this could potentially represent a clinical benefit in reducing the risk for OHSS when using these compounds in controlled ovarian stimulation protocols.

[Ovarian hyperstimulation syndrome: pathophysiology, risk factors, prevention, diagnosis and treatment]

The ovarian hyperstimulation syndrome is a major complication of ovulation induction for in vitro fertilization, with severe morbidity and possible mortality. Whereas its pathophysiology remains ill-established, the VEGF may play a key role as well as coagulation disturbances. Risk factors for severe OHSS may be related to patients characteristics or to the management of the ovarian stimulation. Two types of OHSS are usually distinguished: the early OHSS, immediately following the ovulation triggering and a later and more severe one, occurring in case of pregnancy. As no etiologic treatment is available, the therapeutic management of OHSS should focus on its related-complications. Thrombotic complications that can occur in venous or arterial vessels represent the major risk of OHSS, possibly conducting to myocardial infarction and cerebrovascular accidents. Once the OHSS is diagnosed, prevention of thrombotic accidents remains the major issue.

Effect of bromocriptine on the severity of ovarian hyperstimulation syndrome and outcome in high responders undergoing assisted reproduction

CONTEXT:

Ever since ovarian hyperstimulation syndrome (OHSS) was recognized as a clinical entity, various treatment modalities have been tried to prevent its occurrence and reduce its severity. Many recent studies have evaluated the role of dopamine agonists in reducing the incidence of OHSS.

OBJECTIVES:

To assess the effectiveness of dopamine agonist bromocriptine in reducing the incidence and severity of OHSS in patients undergoing assisted reproduction and its effect on pregnancy rates.

SETTINGS AND DESIGN:

It was a prospective study in which patients at high risk of developing OHSS undergoing assisted reproduction were recruited.

MATERIALS AND METHODS:

The study was carried out from August 2008 to August 2009 in patients undergoing assisted reproduction and included 40 patients at high risk for developing OHSS. Tablet bromocriptine 2.5 mg was prescribed for a period of 16 days starting from day of ovum pick up. Patients were analyzed on the basis of incidence of moderate and severe OHSS, timing of onset of OHSS (early/late), hospitalization rate, pregnancy rates and tolerability of medication and were compared with a historical group of high responders matched for age and BMI.

STATISTICAL ANALYSIS:

Student’s t test and proportion test were used.

RESULTS:

There was a significant reduction in the incidence of moderate OHSS (P=0.037), early OHSS (P=0.012) as well as the number of admissions (P=0.030). Average duration of hospitalization was also significantly reduced (P=0.036). In the study group, the incidence of clinically significant OHSS was 17.5% as compared to 40.9% in the control group. No difference was detected between the groups in clinical pregnancy rates (P=0.0054).

CONCLUSION:

Bromocriptine reduced the incidence and severity of clinically significant OHSS in high risk patients without affecting the pregnancy rates.

Estrogen administration during superovulation increases oocyte quality and expressions of vascular endothelial growth factor and nitric oxide synthase in the ovary

AIMS

This study investigated whether estrogen administration during superovulation enhances oocyte quality using a mice model. We also investigated whether this estrogen treatment regulates the expressions of angiogenic factors, such as vascular endothelial growth factor (VEGF) and endothelial nitric oxide synthase (eNOS), in the ovary.

METHOD

Female mice were co-injected with various doses of estrogen (1 microM, 10 microM and 100 microM) and pregnant mare serum gonadotrophin during superovulation, followed by human chorionic gonadotrophin injection 48 hours later. Then they were mated with individual males. After 18 hours, zygotes were flushed and cultured to blastocyst. The expression of VEGF and eNOS in the ovary was examined using Western blot and immunohistochemistry. The control group was superovulated without estrogen.

RESULTS

Both numbers of ovulated zygotes and the rate of embryo development to blastocyst were significantly increased in the 1-microM estrogen dose compared to the control group. VEGF and eNOS expressions were stimulated by estrogen treatment. In particular, VEGF expression was significantly increased at 1-microM estrogen concentration, whereas, eNOS expression was significantly increased in all estrogen concentrations compared to controls.

CONCLUSIONS

The study showed that estrogen co-injection during superovulation increased the ovarian response, embryo developmental competence and expressions of VEGF and eNOS in the ovary.

The pathophysiology of ovarian hyperstimulation syndrome: an unrecognized compartment syndrome

OBJECTIVE

To compare and contrast the pathophysiology of ovarian hyperstimualtion syndrome (OHSS) with known syndromes of increased intraabdominal pressure (IAP), and to explore the relationship of increased IAP with symptom severity in OHSS.

DESIGN

Literature review.

MAIN OUTCOME MEASURE(S)

Correlation of OHSS symptoms with IAP; effects of paracentesis on IAP in patients with OHSS.

SETTING

Academic Research Institution.

INTERVENTION(S)

None.

RESULT(S)

OHSS involves a rapid accumulation of volume (from 1.5-17 liters) in the peritoneal cavity that can lead to organ dysfunction, including respiratory impairment and oliguria. In published reports of 20 moderate-to-severe OHSS patients in whom IAP was measured, IAP was found to be elevated to a pathologic range. The increased IAP indicates that OHSS may be considered a compartment syndrome and meets criteria for abdominal compartment syndrome in advanced cases. For this reason, management of OHSS should include reduction of pressure by paracentesis to avoid morbidity and syndrome progression. In addition, measurement of IAP may help to classify the stage of OHSS.

CONCLUSION(S)

IAP was found to be elevated in the few cases of OHSS in which it was measured, substantiating the conclusion that OHSS may be considered a compartment syndrome. An understanding of the pathophysiology of increased intrabdominal pressure is useful in the management of OHSS.

Angiogenic imbalances: the obstetric perspective

Clinical and experimental evidence indicates that angiogenic imbalances may participate in the mechanisms of disease of several pregnancy complications, some of which may be life threatening. This article reviews current evidence in support of this view and the possibility that the fetus may play a central role in these imbalances; it also reviews recent experimental observations that modulation of angiogenic imbalances during pregnancy may have prophylactic and/or therapeutic value.

Production and binding of endothelin-2 (EDN2) in the rat ovary: endothelin receptor subtype A (EDNRA)-mediated contraction

Endothelin-2 (EDN2)-mediated contraction has been proposed as a final mechanical signal facilitating ovulation. The objectives herein were to determine (1) whether ovarian endothelins were increased before ovulation; (2) whether a specific endothelin-converting enzyme (ECE) was mediating their production; (3) which receptor was facilitating ovarian contraction; and (4) whether receptor-specific antagonism affected ovulation. Follicular development was induced in immature rats with 10 IU pregnant mare serum gonadotrophin (PMSG) and the ovulatory cascade was initiated 48 h later with 10 IU human chorionic gonadotrophin (hCG). In Experiment 1, an immunoassay revealed that the ovarian concentration of endothelin peptide was increased 7-fold 12 h after hCG when compared with 48 h after PMSG (P < 0.05). In Experiment 2, real-time PCR indicated that mRNA for Ece1, but not Ece2, was increased in granulosa cells collected 12 h after hCG when compared with those collected before the ovulatory stimulus (P < 0.05). In Experiment 3, isometric tension analysis revealed that the contractile effect of EDN2 was mediated by endothelin receptor A (EDNRA), not B (EDNRB). In Experiment 4, no effect was observed on the rate of ovulation when rats were treated with an antagonist specific to EDNRA (BQ123) or EDNRB (BQ788), or when mice were treated with BQ123, BQ788 or BQ123 + BQ788. In conclusion, endothelin peptide is produced before ovulation and the contractile action of EDN2 within the ovary is facilitated via EDNRA. In addition, findings of this study indicate synergistic interactions among contractile factors affect ovulatory outcome, while the role of EDNRB alone in the process of ovulation requires further investigation.

The non-ergot derived dopamine agonist quinagolide in prevention of early ovarian hyperstimulation syndrome in IVF patients: a randomized, double-blind, placebo-controlled trial

BACKGROUND

Ovarian hyperstimulation syndrome (OHSS) seems to be induced by the ovarian release of vascular endothelial growth factor (VEGF), which increases vascular permeability. Dopamine agonists inhibit VEGF receptor phosphorylation and thereby decrease vascular permeability.

METHODS

A randomized, double-blind, placebo-controlled, multicentre study assessing three oral doses (50, 100, 200 µg/day) of the non-ergot derived dopamine agonist quinagolide started on the day of human chorionic gonadotrophin (hCG) and continued for 17–21 days without dose-titration in comparison to placebo in preventing moderate/severe early OHSS (onset ≤9 days after hCG administration) in 182 IVF patients with ≥20 but less than 30 follicles ≥10 mm.

RESULTS

The incidence of moderate/severe early OHSS was 23% (12/53) in the placebo group and 12% (6/51), 13% (7/52) and 4% (1/26) in the quinagolide 50, 100 and 200 µg/day groups, respectively. The moderate/severe early OHSS rate was significantly lower with all quinagolide groups combined compared with placebo [P = 0.019; OR = 0.28 (0.09–0.81)]. The incidence of ultrasound evidence of ascites among patients with no clinical pregnancy was significantly reduced from 31% (8/26) with placebo to 11% (8/70) with all quinagolide groups combined [P = 0.033; OR = 0.29 (0.10–0.88)], although there was no difference for those with clinical pregnancy. Quinagolide did not have a detrimental effect on pregnancy or live birth rates. The incidence of gastrointestinal and central nervous system adverse events increased with increasing doses of quinagolide.

CONCLUSIONS

Quinagolide appears to prevent moderate/severe early OHSS while not affecting treatment outcome. The effect is more marked in patients who did not achieve a clinical pregnancy. Quinagolide administered in high doses without dose-titration is associated with poor tolerability.

ClinicalTrials.gov Identifier: NCT00329693.

Ovarian hyperstimulation syndrome: pathophysiology and prevention

PURPOSE

To review and discuss the pathophysiology and prevention strategies for ovarian hyperstimulation syndrome (OHSS), which is a condition that may occur in up to 20% of the high risk women submitted to assisted reproductive technology cycles.

METHODS

The English language literature on these topics were reviewed through PubMed and discussed with emphasis on recent data.

RESULTS

The role of estradiol, luteinizing hormone, human chorionic gonadotropin (hCG), inflammatory mediators, the renin-angiotensin system and vascular endothelial growth factor is discussed in the pathophysiology of OHSS. In addition we consider the prevention strategies, including coasting, administration of albumin, renin-angiotensin system blockage, dopamine agonist administration, non-steroidal anti-inflammatory administration, GnRH antagonist protocols, reducing hCG dosage, replacement of hCG and in vitro maturation of oocytes (IVM).

CONCLUSIONS

Among the many prevention strategies that have been discussed, the current evidence points to the replacement of hCG by GnRH agonists in antagonist cycles and the performance of IVM procedures as the safest approaches.

The expression of angiogenic growth factors and their receptors in ovarian follicles throughout the estrous cycle in the ewe

Healthy follicles are highly vascularized whereas those undergoing atresia have poor vascularity, suggesting a relationship between follicular vascularization and follicular function. Vascularization is regulated by angiogenic factors, and among them vascular endothelial growth factor (VEGF) and angiopoietin-Tie (Ang-Tie) systems are of central importance. The objectives of this study were to determine if VEGF, VEGF receptor-2 (VEGFR-2), and components of the Ang-Tie system are expressed in ovarian follicles at both the protein and mRNA levels and to explore if their expression is related to the stage of the estrous cycle in the ewe. Ovaries from cyclic ewes were collected during the luteal phase (n=5) or before (n=5), during (n=4), and after (n=4) the preovulatory luteinizing hormone (LH) surge. After fixation, ovaries were wax-embedded, serially sectioned, and analyzed for both protein and mRNA expression of VEGF, VEGFR-2, angiopoietin-1 (Ang-1), angiopoietin-2 (Ang-2), Tie-1 (mRNA only), and Tie-2. mRNA was studied by in situ hybridization using digoxigenin-11-UTP-labeled ovine riboprobes. A similar pattern of expression was observed for mRNA and protein for all of the factors. Both mRNA and protein expression of VEGF, VEGFR-2, Ang-1, Ang-2, Tie-1 (mRNA only), and Tie-2 in the granulosa and theca cells of follicles >or=2mm in diameter was significantly different among the stages of the estrous cycle, with the highest expression detected at the post-LH surge stage. Theca cells expressed significantly greater levels of the six angiogenic factors compared with granulosa cells at all stages of the estrous cycle. Expression levels in granulosa and theca cells were comparable between small (2.0 to 2.5mm) and medium (2.5 to 4.0mm) follicles, but large follicles (>4.0mm) expressed higher mRNA and protein levels (all P<0.05) for all factors at all stages of the estrous cycle. These data show (i) that VEGF, VEGFR-2, and the Ang-Tie system are present in both granulosa and theca cells of the ovarian follicle, (ii) that thecal cells consistently express greater levels of all of these factors compared with granulosa cells, and (iii) that their levels of expression are related to the stage of the estrous cycle and to follicle size.

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.

Role of the phosphatidylinositol-3-kinase and extracellular regulated kinase pathways in the induction of hypoxia-inducible factor (HIF)-1 activity and the HIF-1 target vascular endothelial growth factor in ovarian granulosa cells in response to follicle-stimulating hormone

FSH stimulation of granulosa cells (GCs) results in increased hypoxia-inducible factor (HIF)-1alpha protein levels and HIF-1 activity that is necessary for up-regulation of certain FSH target genes including vascular endothelial growth factor. We report that the role of the phosphatidylinositol (PI)-3-kinase/AKT pathway in increasing HIF-1alpha protein in FSH-stimulated GCs extends beyond an increase in mammalian target of rapamycin-stimulated translation. FSH increases phosphorylation of the AKT target mouse double-minute 2 (MDM2); a phosphomimetic mutation of MDM2 is sufficient to induce HIF-1 activity. The PI3-kinase/AKT target forkhead box-containing protein O subfamily 1 (FOXO1) also effects the accumulation of HIF-1alpha as evidenced by the ability of a constitutively active FOXO1 mutant to inhibit the induction by FSH of HIF-1alpha protein and HIF-1 activity. Activation of the PI3-kinase/AKT pathway in GCs by IGF-I is sufficient to induce HIF-1alpha protein but surprisingly not HIF-1 activity. HIF-1 activity also appears to require a PD98059-sensitive protein (kinase) activity stimulated by FSH that is both distinct from mitogen-activated ERK kinase1/2 or 5 and independent of the PI3-kinase/AKT pathway. These results indicate that FSH-stimulated HIF-1 activation leading to up-regulation of targets such as vascular endothelial growth factor requires not only PI3-kinase/AKT-mediated activation of mammalian target of rapamycin as well as phosphorylation of FOXO1 and possibly MDM2 but also a protein (kinase) activity that is inhibited by the classic ERK kinase inhibitor PD98059 but not ERK1/2 or 5. Thus, regulation of HIF-1 activity in GCs by FSH under normoxic conditions is complex and requires input from multiple signaling pathways.

In vivo effect of an luteinizing hormone-releasing hormone analog on vascular endothelial growth factor and epidermal growth factor receptor expression in mammary tumors

BACKGROUND

The hypothalamic luteinizing hormone-releasing hormone (LHRH) is well known for its role in the control of pituitary gonadotropin secretion and it has demonstrated a direct antiproliferative effect on some cancer cell lines of LHRH and its synthetic analogs. The study was designed to assess whether administration of the LHRH analog (goserelin) has any effect on the expression of the vascular endothelial growth factor (VEGF) and the epidermal growth factor receptor (EGFR) in rats with N-nitroso-N-methylurea (NMU)-induced-mammary tumors " in vivo".

MATERIALS AND METHODS

The animals with tumors were assessed after acute or chronic treatment with goserelin, and in all the animals VEGF and EGFR expression was examined both in plasma and tumor homogenates by enzyme immunoassay.

RESULTS

The basal plasma values of VEGF were lower in the healthy control group than in rats with NMU-induced tumors ( P = 0.025). Following acute treatment with goserelin, VEGF expression in plasma increased above basal levels after 60 min ( P = 0.05) and dropped during chronic treatment. Likewise, in the tumor homogenate the mean VEGF expression was higher at 60 min post-goserelin administration than the basal levels, although VEGF expression then diminished at 90 min. Plasma EGFR expression was higher in rats with NMU-induced tumors than in healthy controls ( P Conclusions: The results allow us to conclude that goserelin may exert a short-term stimulatory effect on the release of VEGF, as well as a long-term inhibitory effect on VEGF but not EGFR expression.