Prevention of ovarian hyperstimulation syndrome in a rat model: efficacy comparison between cabergoline and meloxicam

Does cabergoline administration affect endometrial VEGFR-2 expression in a rat model of ovarian hyperstimulation syndrome?

OBJECTIVE

To assess the effect of cabergoline on endometrial vascular endothelial growth factor receptor-2 (VEGFR-2) immunoexpression in an ovarian hyperstimulation syndrome (OHSS) rat model.

MATERIAL AND METHODS

Twenty-one immature female Wistar rats were assigned into three groups: group 1, the control group; group 2, stimulated with gonadotropins to mimic OHSS; and group 3, in which an OHSS protocol was induced and thereafter treated with cabergoline (100 μg/kg/day). Body weight, ovarian volume, corpora lutea numbers, and endometrial VEGFR-2 expression were compared between the groups.

RESULTS

Weight gain and ovarian volume were highest in the OHSS-placebo group, while cabergoline administration significantly reversed those effects (p = 0.001 and p = 0.001, respectively). VEGFR-2 stained cells were significantly lower in groups 2 and 3 compared to group 1 (p = 0.002). Although VEGFR-2 expression was lowest in group 3, the difference was not statistically significant. Corpora lutea numbers were also similar (p = 0.465).

CONCLUSION

While successful implantation requires a vascularized receptive endometrium, impaired expression of VEGFR-2 and disrupted endometrial angiogenesis due to cabergoline administration may be associated with IVF failure in fresh OHSS cycles. The insignificant decrease in endometrial VEGFR-2 expression observed in this research needs to be investigated by further studies involving additional techniques such as immunoblotting and/or RT-PCR analyses.

Effect of ondansetron for preventing of ovarian hyperstimulation syndrome: in an experimental rat model

Objective: Ovarian hyperstimulation syndrome is an iatrogenic condition that occurs in the treatment of infertility. There is no specific treatment available for OHSS. Cabergoline is a dopamine receptor 2 agonist and VEGF-VEGF2 receptor antagonist . Recently, cabergoline has been widely used to prevent the development of OHSS and reduce its severity Serotonin is known as a neurotransmitter and thought to have a role in the mechanism of angiogenesis and in signaling in endothelial cells. Serotonin is said to have similar effects to VEGF . Ondansetron is Selective Serotonin (5-HT3) Receptor Antagonist . It works by blocking the action of serotonin, a natural substance that may cause nausea and vomiting. In the clinical practice today, there is no choice other than cabergoline, to prevent occurrence and reduce severity of OHSS, and sometimes its effects are limited. Methods: In our study, we compared the effect of cabergoline and ondansetron. 32 immature rats were used and the OHSS model was created. Parameters such as hematocrit value , ovarian size, the number of follicles in the ovary, endometrial capillary congestion and thickness values were evaluated and compared. Results: As a result, in our study, it was seen that ondansetron was effective on OHSS in many parameters. It is thought to be as effective as cabergoline. When we look at the literature, this is the first study in which ondansetron was evaluated for this purpose. It would be good to show this effect of ondansetron with other studies.

Oxytocin and cabergoline alleviate ovarian hyperstimulation syndrome (OHSS) by suppressing vascular endothelial growth factor (VEGF) in an experimental model

PURPOSE

Ovarian hyperstimulation syndrome (OHSS) is a life-threatening complication of ovarian stimulation in reproductive medicine. Here, we aimed to investigate the role of oxytocin (OT) and cabergoline in the prevention and alleviation of the OHSS in an animal model.

METHODS

Thirty-five female immature Wistar rats were randomly assigned to five groups. The control group (n = 7) received saline only for five consecutive days. Remaining twenty-eight rats received 10 IU of pregnant mare serum gonadotropin (PMSG) followed by 30 IU of human chorionic gonadotropin (hCG) to induce OHSS. Group 2 (n = 7) was managed with no additional intervention after the induction of OHSS. Group 3 (n = 7) received 100 μg/kg cabergoline 2 h before the PMSG injection for four consecutive days and 2 h before the hCG injection on the fifth day. Group 4 (n = 7) and group 5 (n = 7) received 80 μg/kg and 160 μg/kg OT after induction of OHSS, respectively. Oxytocin was administered 2 h before the PMSG injection for four consecutive days and 2 h before the hCG injection on the fifth day. Body and ovary weight, vascular permeability (VP), VEGF expression in the ovaries, and levels of VEGF in the peritoneal fluids were examined in all animals.

RESULTS

Cabergoline and OT reduced body weight, ovary weight, and VP compared to that of the OHSS group (p < 0.05). VEGF expressions in ovaries and peritoneal VEGF levels were decreased in cabergoline and OT groups compared to that of the OHSS groups (p < 0.001 for cabergoline and OT-80 μg/kg; p < 0.00001 for OT-160 μg/kg). However, there was no statistically significant difference in these parameters between the OT and cabergoline groups.

CONCLUSION

Both OT and cabergoline were active in the alleviation of OHSS through suppression of VEGF and VP. Overall, we conclude that OT is effective for downregulation for VEGF and improvement in vascular permeability in OHSS.

Comparison of the effects of letrozole and cabergoline on vascular permeability, ovarian diameter, ovarian tissue VEGF levels, and blood PEDF levels, in a rat model of ovarian hyperstimulation syndrome

OBJECTIVE

To evaluate the effects of letrozole and cabergoline in a rat model of ovarian hyperstimulation syndrome (OHSS).

STUDY DESIGN

In this prospective, controlled experimental study, the 28 female Wistar rats were divided into four subgroups (one non-stimulated control and three OHSS-positive groups: placebo, letrozole, and cabergoline). To induce OHSS, rats were injected with 10 IU of pregnant mare serum gonadotropin from day 29 to day 32 of life, followed by subcutaneous injection of 30 IU hCG on day 33. Letrozole rats received with a single dose of 0.1 mg/kg letrozole via oral gavage, on the hCG day. Cabergoline rats received with a single dose of 100 µg/kg cabergoline via oral gavage, on the hCG day. All animals were compared in terms of body weight, vascular permeability (VP), ovarian diameter, ovarian tissue VEGF expression (assessed via immunohistochemical staining), and blood pigment epithelium-derived growth factor (PEDF) levels.

RESULTS

The OHSS-positive placebo group (group 2) exhibited the highest VP, ovarian diameter, extent of VEGF staining, and lowest PEDF level, as expected. No significant difference was evident between the letrozole and cabergoline groups in terms of any of body weight; VP; PEDF level; ovarian diameter; or the staining intensity of, or percentage staining for, VEGF in ovarian tissues.

CONCLUSIONS

Letrozole and cabergoline were equally effective to prevent OHSS, reducing the ovarian diameter, VP, and PEDF and VEGF levels to similar extents.

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.

Ovarian hyperstimulation syndrome inhibition by targeting VEGF, COX-2 and calcium pathways: a preclinical randomized study

OBJECTIVE

The efficacy of vascular endothelial growth factor (VEGF), COX-2, calcium and aromatase inhibitors in an ovarian hyperstimulation syndrome (OHSS) rat model was tested.

METHODS

One hundred and eight female Wistar rats were randomly divided in nine groups. The control group received saline, while the OHSS group received rec-FSH for 4 consecutive days. The other seven groups received rec-FSH (4d) and Bevacizumab twice, Parecoxib daily, Verapamil daily, Parecoxib daily and Bevacizumab twice, Verapamil daily and Bevacizumab twice, Parecoxib and Verapamil daily, Letrozole and Meloxicam daily, respectively. All groups received also hCG at the 5th day.

RESULTS

All intervention groups were characterized by reduced vascular permeability compared to the OHSS group, which in the groups of Verapamil (Calcium inhibition) and Parecoxib + Verapamil (COX-2 + Calcium inhibition) presented significant statistical difference. The Verapamil group showed the lowest corpus luteum formation, while the Parecoxib (COX-2 inhibition), the Parecoxib + Verapamil (COX-2 + Calcium inhibition), the Bevacizumab + Parecoxib (VEGF + COX-2 inhibition) and the Bevacizumab + Verapamil (VEGF + Calcium inhibition) groups were also characterized by lower corpus luteum numbers compared to the OHSS group. Furthermore, lower graafian follicle formation was observed in the above groups, while the ovarian weight and the hormonal profile were not significantly affected.

CONCLUSIONS

Studying the different check points of the VEGF pathway, we conclude that targeting calcium pathways could be beneficial for the vascular permeability control in an OHSS animal model.

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.

Comparison of bevacizumab and cabergoline in the treatment of ovarian hyperstimulation syndrome in a rat model

The aim of this study is to investigate the effects of bevacizumab in a rat model of ovarian hyperstimulation syndrome (OHSS) and compare with cabergoline. The study was performed with 24 rats in four main groups (one non-stimulated control and three OHSS treatment groups; bevacizumab, cabergoline and placebo). The rats were randomly assigned to four experimental groups (six rats per group). Efficacy of treatment was assessed on 29th day by measuring weight gain, number of eggs, presence of ascites and ovarian weight. Peritoneal fluid levels of vascular endothelial growth factor (VEGF) were measured using an enzyme-linked immunosorbent assay. Ovarian weights were significantly higher in the OHSS groups than the control group. Ovarian weights in OHSS placebo group were found to be higher than those in OHSS-treatment groups (p = 0.002). VEGF levels were found increased in the OHSS-placebo group compared with the control group (p < 0.05). This increase was not seen in the OHSS groups treated with either bevacizumab or cabergoline. We demonstrate in this study that bevacizumab can lower VEGF production and ovarian weight in rats treated with gonadotropins.

Cabergoline for preventing ovarian hyperstimulation syndrome

BACKGROUND

Ovarian hyperstimulation syndrome (OHSS) is a complication resulting from administration of human chorionic gonadotrophin (hCG) in assisted reproduction technology (ART) treatment. Most case are mild, but forms of moderate or severe OHSS appear in 3% to 8% of in vitro fertilisation (IVF) cycles. Recently, the dopamine agonist cabergoline has been introduced as a secondary prevention intervention for OHSS in women at high risk of OHSS who are undergoing ART treatment.

OBJECTIVES

To assess the effectiveness and safety of cabergoline in preventing ovarian hyperstimulation syndrome (OHSS) in high-risk women undergoing ART treatment.

SEARCH METHODS

Major medical databases (Cochrane Menstrual Disorders and Subfertility Group Specialised Register of trials, CENTRAL (The Cochrane Library), MEDLINE, EMBASE and PsycINFO) were systematically searched for randomised controlled trials (RCTs) assessing the effect of cabergoline in preventing OHSS. Databases were searched up to September 2011. Registers of clinical trials, abstracts of scientific meetings and reference lists of included studies were searched. No language restrictions were applied.

SELECTION CRITERIA

RCTs which compared cabergoline with placebo, no treatment or another intervention for preventing OHSS in high-risk women were considered for inclusion. Primary outcome measures included incidence of moderate or severe OHSS and live birth rate. Secondary endpoints were clinical pregnancy rate, multiple pregnancy rate, miscarriage rate and any other adverse effects of the treatment.

DATA COLLECTION AND ANALYSIS

Two authors independently screened titles, abstracts and the full text of publications; extracted data; and assessed risk of bias. Any disagreements were resolved by consensus. Pooled results were reported as odds ratio (OR) and 95% confidence interval (95% CI) by the Mantel-Haenszel method.

MAIN RESULTS

Only two trials involving 230 women met the inclusion criteria. Both studies had a moderate risk of bias. Oral cabergoline, 0.5 mg daily, was given as an intervention and compared with a matched placebo. A statistically significant reduction in OHSS was observed in the cabergoline treated group (OR 0.40, 95% CI 0.20 to 0.77; 2 RCTs, 230 women) with a number needed to treat (NTT) of 7. There was a statistically significant difference in the incidence of moderate OHSS, favouring cabergoline (OR 0.38, 95% CI 0.19 to 0.78; 2 RCTs, 230 women) but not in severe OHSS (OR 0.77, 95% CI 0.24 to 2.45; 2 RCTs, 230 women). There was no significant difference in the clinical pregnancy rate (OR 0.94, 95% CI 0.56 to 1.59; 2 RCTs, 230 women), miscarriage rate (OR 0.31, 95% CI 0.03 to 3.07; 1 RCT, 163 women) or any other adverse effects of the treatment (OR 2.07, 95% CI 0.56 to 7.70; 1 RCT, 67 women). However, no data on multiple pregnancy rate or live birth rate were reported in either trial.

AUTHORS' CONCLUSIONS

Cabergoline appears to reduce the risk of OHSS in high-risk women, especially for moderate OHSS. The use of cabergoline does not affect the pregnancy outcome (clinical pregnancy rate, miscarriage rate), nor is there an increased risk of adverse events. Further research should consider the risk of administering cabergoline and the comparison between cabergoline and established treatments (such as intravenous albumin and coasting). Large, well-designed and well-executed RCTs that involve more clinical endpoints are necessary to further evaluate the role of cabergoline in OHSS prevention.

Comparison of cabergoline and intravenous albumin in the prevention of ovarian hyperstimulation syndrome: a randomized clinical trial

PURPOSE

To compare the efficacy of cabergoline (Cb2) and intravenous human albumin (HA) in the prevention of ovarian hyperstimulation syndrome.

METHODS

In this randomized controlled trial study, 138 women who were at high risk for developing OHSS were randomly allocated into two groups. In Group one, 20 gr of HA 20% was infused over 1 h. Group two received 0.5 mg per day of Cb2 orally for 7 days, starting on oocyte pickup day. All patients were visited seven and 14 days after oocyte retrieval to determine early clinical or ultrasound evidence of OHSS.

RESULTS

Moderate OHSS was observed in 33 versus 14 cases in the HA and Cb2 groups, respectively, which was significantly different. The number of severe OHSS cases in the HA group was significantly higher than in the Cb2 group (P < 0.001).

CONCLUSIONS

Prophylactic oral low dose cabergoline was more effective and less costly than intravenous human albumin in the prevention of OHSS in high-risk patients.