- Email: [email protected]
Differential regulation of VEGF after final oocyte maturation with GnRH agonist versus hCG: a rationale for OHSS reduction
Differential regulation of VEGF after final oocyte maturation with GnRH agonist versus hCG: a rationale for OHSS reduction In a prospective cohort study, we compared the effect of hCG and GnRH agonist triggering of final oocyte maturation on vascular endothelial growth factor production. Vascular endothelial growth factor follicular fluid concentration was significantly lower in response to GnRH agonist versus hCG, which may partially explain the absence of OHSS in these of women. (Fertil Steril 2009;91:1526–8. 2009 by American Society for Reproductive Medicine.)
Ovarian hyperstimulation syndrome (OHSS) is an iatrogenic complication of assisted reproductive treatments that are carried out with hCG to induce final oocyte maturation. The pathophysiologic mechanism that fully explains OHSS is still unknown, and therefore the majority of the therapeutic approaches to OHSS have been empirical. It occurs in 0.1%–4% of all the treatments that require controlled ovarian hyperstimulation (1). It has been demonstrated that after administration of hCG, the ovary releases different vasoactive substances that induce an increase in vascular permeability and fluid leakage to the third space, with ascites, and even hydrothorax and anasarca in severe cases, as the final consequence (2). One of the key vasoactive substances released is vascular endothelial growth factor (VEGF) (3, 4). We (5–8) and others (9) have shown that VEGF, among other proinflammatory cytokines, plays a fundamental role in the pathophysiology of OHSS. An attractive approach to avoid OHSS is to substitute hCG, which has a very long half-life, for another drug that may induce enough of an endogenous LH peak enough to induce final oocyte maturation. Gonadotropin-releasing hormone agonists have been successfully used in this way in egg donors, and not only are these agonists able to reduce the incidence of OHSS, but also the number of oocytes retrieved, egg quality, and implantation and pregnancy rates in egg recipients remain unaltered (10). However, the short half-life of the endogenous LH peak is not enough to have an adequate luteal phase. Most of the studies performed in patients showed reduced implantation and pregnancy rates, probably due to the insufficient luteal support by the short LH peak that exogenous progesterone alone was not enough to restore (12), although some groups have shown results Received August 5, 2008; revised and accepted August 25, 2008; published online November 5, 2008. M.C. has nothing to disclose. S.R. has nothing to disclose. M.M. has nothing to disclose. A.P. has nothing to disclose. J.M.-S. has nothing to disclose. J.G.-V. has nothing to disclose. Reprint requests: Juan A. Garcia-Velasco, M.D., IVI-Madrid, Santiago de Compostela 88, 28035 Madrid, Spain (FAX: 34 91 376 9920; E-mail: [email protected]).
1526
similar to cycles where hCG was given (11). Human corpus luteum produces many more biologically active products than just progesterone; therefore, further research is required on how to supplement luteal phase in these patients to optimize cycle outcome (13). The aim of the present study was to investigate VEGF regulation in both serum and follicular fluid in patients undergoing IVF/intracytoplasmic sperm injection cycles comparing the effect of hCG to induce final oocyte maturation with that of a bolus of GnRH agonist. MATERIALS AND METHODS This was a prospective cohort study performed between October and December 2007 at a university-affiliated private infertility center. We included 39 oocyte donors undergoing standardized COH protocols for egg donation. All donors were included in our oocyte donation program after being thoroughly informed and having fulfilled our inclusion criteria. Subjects were aged between 18 and 35 years, and we had access to their complete medical history, which considered current or past exposure to radiation or hazardous chemical substances, IV drug use, and reproductive history. All subjects were shown to be normal in a physical and gynecologic examination, had no family history of hereditary or chromosomal diseases, had a normal karyotype, and tested negative in a screening for sexually transmitted diseases. An economic compensation stipulated by the Spanish government was given to the oocyte donor with the aim of mitigating the physical burden, job restrictions, and the number of times the donor had to come to the clinic during an ovarian stimulation cycle. Informed consent was given bey every patient before recruitment, and the trial was approved by the institutional ethical committee. Patient Population Thirty-nine donors were recruited and allocated in a nonrandomized fashion to receive either hCG (group 1) or GnRH agonist (group 2) after COH.
Fertility and Sterility Vol. 91, No. 4, Supplement, April 2009 Copyright ª2009 American Society for Reproductive Medicine, Published by Elsevier Inc.
0015-0282/09/$36.00 doi:10.1016/j.fertnstert.2008.08.118
Ovarian Stimulation Donors in group 1 (n ¼ 19) underwent COH according to our routine standard long protocol, as previously described (10), with 150 IU rFSH as starting dose. Donors in group 2 (n ¼ 20) underwent COH with similar doses of gonadotropins as in our routine protocol, but when the leading follicle reached 14 mm, GnRH antagonist was started. When at least two follicles reached 18 mm in mean diameter, either 6,500 IU SC rhCG (Ovitrelle, Serono, Madrid, Spain) or a single bolus of 0.2 mg SC triptorelin (Decapeptyl; Ipsen Pharma, Madrid, Spain) was given and egg retrieval performed 36 h later. No luteal support was given. Determination of VEGF Concentrations Plasma samples were obtained from all donors the day of hCG/GnRH agonist administration and the day of oocyte retrieval in tubes containing EDTA as anticoagulant. All plasma samples were centrifuged at 900g for 10 min at room temperature, and the cell-free supernatants were stored immediately in aliquots at L80 C until assayed. Follicular fluid from the first two mature follicles was aspirated into 10-mL tubes by transvaginal ultrasonographic-guided oocyte retrieval. The needle was withdrawn and completely emptied before each puncture, and no culture medium was used in the collection tubes. After removal of oocytes, follicular aspirates were centrifuged at 200g for 5 min, and supernatant was stored at L80’C until assayed. All samples were evaluated collectively by two investigators who were blinded to patient assignment. Concentrations of soluble VEGF165 in plasma and follicular fluid were determined with a commercially available ELISA kit (Quantikine; R&D Systems, Abingdon, UK) according to the manufacturer’s instructions. The assay sensitivity was 5 pg/mL. The inter- and intra-assay coefficients of variation were <7% and < 4.5%, respectively. Statistical Analysis Categoric data were expressed as number and percentage, and numerical data as mean SEM. Student t test and c2 test were used when appropriate. Significance was set at .05. All statistical analysis was performed with use of Sigmastat for Windows, version 2.0 (Jandel Scientific Corporation, San Rafael, CA). RESULTS Relevant clinical data, basically body mass index (21.5 2.9kg/m2 vs. 22.04 2.3 kg/m2) and age (25.4 4 yrs vs. 23.8 3.9 yrs), from both groups of oocyte donors were similar. Both groups showed similar cycle outcomes in terms of duration of the stimulation (8.5 1.1 vs. 8.9 1.2 days; P¼.29), total dose of rFSH (1,307 235 IU vs. 1,377 234 IU; P¼.35), peak serum E2 (2,537 1,032 vs. 2,095 979 pg/mL; P¼.17), serum P levels the day Fertility and Sterility
of hCG/GnRHa administration (0.8 0.5 ng/mL vs. 0.8 0.3 ng/mL; P¼78), and oocytes retrieved (14 4 vs. 17 8; P¼.12). We did find differences in the duration of the luteal phase: The period to menstrual onset in the non-hCG group was significantly shorter (10.2 1.1 days vs. 5.2 1.6 days; P<.001). Also, in the routine control we do to all our donors 1 week after the ovarian puncture, 42% of those who received hCG reported subjective complaints (mostly abdominal discomfort), whereas this percentage was 0% in those who received GnRH agonist to trigger ovulation. No OHSS was observed in either cohort. We did not find any differences in plasma levels of VEGF in either group, whether it was the day of hCG/GnRHa or the day of ovum pick-up (Table 1). However, a significant reduction in follicular fluid VEGF concentration was observed in those follicles coming from donors that received GnRHa instead of hCG (1,666 53 [95% confidence interval (CI) 1,267–1,946] pg/mL vs. 1,207 135 [95% CI 436–2,117] pg/mL; P<.001). DISCUSSION To our knowledge, this is the first report investigating the differential secretion of a soluble vascular mediator (VEGF) when final oocyte maturation is induced by either hCG or a single bolus of GnRHa. The significantly lower concentrations of VEGF in the follicular fluid of patients who received GnRHa have direct clinical consequences to prevent OHSS. Vascular endothelial growth factor is the key molecule among the different vascular mediators released from the ovaries and other tissues in response to hCG (3–7, 9). The long half-life of hCG of around 7 days, due to the continuous stimulus and liberation of vasoactive mediators, may complicate some assisted reproduction patients with OHSS, a potentially life-threatening consequence (13). Therefore, the search for a surrogate for hCG has been crucial. Clinical empirical observations had previously confirmed that finding a surrogate for hCG that was able to induce final oocyte maturation was feasible and safe. For instance, exogenous LH could be an option, but impractical due to the high cost (13). An alternative, in those patients undergoing COH with the antagonist—so the pituitary is not desensitized—is a bolus of GnRH agonist. Preliminary observations confirmed that the number of oocytes retrieved, fertilization, and embryo quality were unaffected (10). However, some controversy was raised, because implantation and pregnancy rates seemed to be diminished (11–13), although not all authors agreed (14). The fact that using this protocol in donors did not affect recipients’ outcome clarified that the hypothetic reduction in cycle outcome was related to luteal support, an area that needs further research. Previous research by Babayof et al. (15) regarding VEGF differential regulation by hCG or GnRH agonist did not find
1527
TABLE 1 Plasma and follicular fluid VEGF concentration (pg/mL). hCG n [ 19 Plasma, day of hCG or GnRHa Plasma, day of egg retrieval Follicular fluid
GnRHa n [ 20
P value
158 26 (44–326)
173 23 (63–314)
NS
193 28 (81–381)
219 27 (81–411)
NS
1,666 53 (1,267–1946)
1,207 135 (436–2,117)
< .001
Note: Values are presented as mean SEM (95% confidence interval). GnRH ¼ GnRH agonist. Cerrillo. VEGF production after hCG or GnRH agonist. Fertil Steril 2009.
significant differences in serum. The facts that VEGF was measured only in serum—and not in plasma—and that follicular fluid VEGF concentrations were not evaluated could explain their findings. Because VEGF is secreted by granulosa cells, the ideal biologic sample to evaluate it would be follicular fluid, and indeed, differences were significant. A limitation of the present work is that we used two different protocols (standard long and antagonist) in our donors. However, this should not be a major drawback, because similar concentrations of VEGF have been found in serum and follicular fluid of women undergoing these two protocols (16). Obviously, owing to the limited sample size, we cannot exclude other causes apart from the reduced follicular fluid VEGF concentration that may contribute to the absence of OHSS in this series. To conclude, we have demonstrated that intrafollicular VEGF concentration is reduced when final oocyte maturation is induced by a single bolus of GnRH agonist instead of hCG, which may cause luteolysis and thus contribute to reducing the incidence of OHSS. This observation, together with a shorter duration of the luteal phase, a minimal discomfort for the donor, and the previous evidence that oocyte/embryo quality is not affected, should help us to implement this approach as the routine standard protocol in oocyte donors. Maria Cerrillo, M.D.a Sara Rodrıguez, Ph.D.a Mercedes Mayoral, M.D.a Alberto Pacheco, Ph.D.a Javier Martınez-Salazar, M.D.a Juan A. Garcia-Velasco, M.D.a,b a IVI-Madrid; and b Rey Juan Carlos University, Madrid, Spain REFERENCES 1. Navot D, Bergh PA, Laufer N. Ovarian hyperstimulation syndrome in novel reproductive technologies: prevention and treatment. Fertil Steril 1992;58:249–61. 2. Balasch J, Fabregues F, Arroyo V. Peripheral arterial vasodilation hypothesis: a new insight into pathogenesis of ovarian hyperstimulation syndrome. Hum Reprod 1998;13:2718–30. 3. McClure N, Healy DL, Rogers PA, Sullivan J, Beaton L, Haning RV. Vascular endothelial growth factor as capillary permeability agent in ovarian hyperstimulation syndrome. Lancet 1994;344:235–6.
1528
Cerrillo et al.
Correspondence
4. Abramov Y, Barak V, Nisman B, Schenker JG. Vascular endothelial growth factor plasma levels correlate to the clinical picture in severe ovarian hyperstimulation syndrome. Fertil Steril 1997;68:133–7. 5. Pellicer A, Albert C, Mercader A, Bonilla-Musoles F, Remohi J, Simon C. The pathogenesis of ovarian hyperstimulation syndrome: in vivo studies investigating the role of interleukin (IL)-1b, IL-6, and vascular endothelial growth factor (VEGF). Fertil Steril 1999;71:482–9. 6. Gomez R, Simon C, Remohi J, Pellicer A. Vascular endothelial growth factor receptor-2 activation induces vascular permeability in hyperstimulated rats, and this effect is prevented by receptor blockade. Endocrinology 2002;143:4339–48. 7. Gomez R, Simon C, Remohi J, Pellicer A. Administration of moderate and high doses of gonadotropins to female rats incesaes ovarian vascular endomthelial growth factor (VEGF) ans VEGF receptor 1 expression that is asssociated to vascular hypermeability. Biol Reprod 2003;68:2164–71. 8. Villasante A, Pacheco A, Pau E, Ruiz A, Pellicer A, Garcia-Velasco JA. Soluble vascular endothelial-cadherin levels correlate with clinical and biological aspects of severe ovarian hyperstimulation syndrome. Hum Reprod 2008;23:662–7. 9. Soares S, Gomez R, Simon C, Garcia-Velasco J, Pellicer A. Targeting the vascular endothelial growth factor system to prevent ovarian hyperstimulation syndrome. Hum Reprod Update 2008;14:321–33. 10. Acevedo B, Gomez-Palomares JL, Ricciarelli MD, Herna´ndez E. Triggering ovulation with gonadotropin-releasing hormone agonist does not compromise embryo implantation rates. Fertil Steril 2006;86:1682–7. 11. Engmann L, Siano L, Schmidt D, Nulsen J, Maier D, Benadiva C. GnRH agonist to induce oocyte maturation during IVF in patients at high risk of OHSS. Reprod Biomed Online 2006;13:639–44. 12. Griesenger G, Diedrich K, Devroey P, Kolibianakis E. GnRH agonist for triggering final oocyte maturation in the GnRH antagonist ovarian hyperstimulation protocol: a systematic review and meta-analysis. Hum Reprod Update 2006;12:159–68. 13. Kol S, Solt I. GnRH agonist for triggering final oocyte maturation in patients at risk of ovarian hyperstimulation syndrome: still a controversy? J Assist Reprod Genet 2008;25:63–6. 14. Engman L, DiLuigi A, Schmidt D, Nulsen J, Maier D, Benadiva C. The use of gonadotropin-releasing hormone (GnRH) agonist to induce oocyte maturation after cotreatment with GnRH antagonist in high-risk patients undergoing in vitro fertilization prevents the risk of ovarian hyperstimulation syndrome: a prospective randomized controlled study. Fertil Steril 2008;89:84–91. 15. Babayof R, Margalioth E, Huleihel M, Amash A, Zylber-Haran E, Gal M, et al. Serum inhibin A, VEGF and TNFa levels after triggering oocyte maturation with GnRH agonist compared with HCG in women with polycystic ovaries undergoing IVF treatment: a prospective randomized trial. Hum Reprod 2006;21:1260–5. 16. Asimakopoulos B, Ko¨ster F, Felberbaum R, Al-Hasani S, Diedrich K, Nikolettos N. Cytokine and hormonal profile in blood serum and follicular fluids during ovarian stimulation with the multidose antagonist or the long agonist protocol. Hum Reprod 2006;21: 3091–5.
Vol. 91, No. 4, Supplement, April 2009
Ovarian hyperstimulation syndrome (OHSS) is an iatrogenic complication of assisted reproductive treatments that are carried out with hCG to induce final oocyte maturation. The pathophysiologic mechanism that fully explains OHSS is still unknown, and therefore the majority of the therapeutic approaches to OHSS have been empirical. It occurs in 0.1%–4% of all the treatments that require controlled ovarian hyperstimulation (1). It has been demonstrated that after administration of hCG, the ovary releases different vasoactive substances that induce an increase in vascular permeability and fluid leakage to the third space, with ascites, and even hydrothorax and anasarca in severe cases, as the final consequence (2). One of the key vasoactive substances released is vascular endothelial growth factor (VEGF) (3, 4). We (5–8) and others (9) have shown that VEGF, among other proinflammatory cytokines, plays a fundamental role in the pathophysiology of OHSS. An attractive approach to avoid OHSS is to substitute hCG, which has a very long half-life, for another drug that may induce enough of an endogenous LH peak enough to induce final oocyte maturation. Gonadotropin-releasing hormone agonists have been successfully used in this way in egg donors, and not only are these agonists able to reduce the incidence of OHSS, but also the number of oocytes retrieved, egg quality, and implantation and pregnancy rates in egg recipients remain unaltered (10). However, the short half-life of the endogenous LH peak is not enough to have an adequate luteal phase. Most of the studies performed in patients showed reduced implantation and pregnancy rates, probably due to the insufficient luteal support by the short LH peak that exogenous progesterone alone was not enough to restore (12), although some groups have shown results Received August 5, 2008; revised and accepted August 25, 2008; published online November 5, 2008. M.C. has nothing to disclose. S.R. has nothing to disclose. M.M. has nothing to disclose. A.P. has nothing to disclose. J.M.-S. has nothing to disclose. J.G.-V. has nothing to disclose. Reprint requests: Juan A. Garcia-Velasco, M.D., IVI-Madrid, Santiago de Compostela 88, 28035 Madrid, Spain (FAX: 34 91 376 9920; E-mail: [email protected]).
1526
similar to cycles where hCG was given (11). Human corpus luteum produces many more biologically active products than just progesterone; therefore, further research is required on how to supplement luteal phase in these patients to optimize cycle outcome (13). The aim of the present study was to investigate VEGF regulation in both serum and follicular fluid in patients undergoing IVF/intracytoplasmic sperm injection cycles comparing the effect of hCG to induce final oocyte maturation with that of a bolus of GnRH agonist. MATERIALS AND METHODS This was a prospective cohort study performed between October and December 2007 at a university-affiliated private infertility center. We included 39 oocyte donors undergoing standardized COH protocols for egg donation. All donors were included in our oocyte donation program after being thoroughly informed and having fulfilled our inclusion criteria. Subjects were aged between 18 and 35 years, and we had access to their complete medical history, which considered current or past exposure to radiation or hazardous chemical substances, IV drug use, and reproductive history. All subjects were shown to be normal in a physical and gynecologic examination, had no family history of hereditary or chromosomal diseases, had a normal karyotype, and tested negative in a screening for sexually transmitted diseases. An economic compensation stipulated by the Spanish government was given to the oocyte donor with the aim of mitigating the physical burden, job restrictions, and the number of times the donor had to come to the clinic during an ovarian stimulation cycle. Informed consent was given bey every patient before recruitment, and the trial was approved by the institutional ethical committee. Patient Population Thirty-nine donors were recruited and allocated in a nonrandomized fashion to receive either hCG (group 1) or GnRH agonist (group 2) after COH.
Fertility and Sterility Vol. 91, No. 4, Supplement, April 2009 Copyright ª2009 American Society for Reproductive Medicine, Published by Elsevier Inc.
0015-0282/09/$36.00 doi:10.1016/j.fertnstert.2008.08.118
Ovarian Stimulation Donors in group 1 (n ¼ 19) underwent COH according to our routine standard long protocol, as previously described (10), with 150 IU rFSH as starting dose. Donors in group 2 (n ¼ 20) underwent COH with similar doses of gonadotropins as in our routine protocol, but when the leading follicle reached 14 mm, GnRH antagonist was started. When at least two follicles reached 18 mm in mean diameter, either 6,500 IU SC rhCG (Ovitrelle, Serono, Madrid, Spain) or a single bolus of 0.2 mg SC triptorelin (Decapeptyl; Ipsen Pharma, Madrid, Spain) was given and egg retrieval performed 36 h later. No luteal support was given. Determination of VEGF Concentrations Plasma samples were obtained from all donors the day of hCG/GnRH agonist administration and the day of oocyte retrieval in tubes containing EDTA as anticoagulant. All plasma samples were centrifuged at 900g for 10 min at room temperature, and the cell-free supernatants were stored immediately in aliquots at L80 C until assayed. Follicular fluid from the first two mature follicles was aspirated into 10-mL tubes by transvaginal ultrasonographic-guided oocyte retrieval. The needle was withdrawn and completely emptied before each puncture, and no culture medium was used in the collection tubes. After removal of oocytes, follicular aspirates were centrifuged at 200g for 5 min, and supernatant was stored at L80’C until assayed. All samples were evaluated collectively by two investigators who were blinded to patient assignment. Concentrations of soluble VEGF165 in plasma and follicular fluid were determined with a commercially available ELISA kit (Quantikine; R&D Systems, Abingdon, UK) according to the manufacturer’s instructions. The assay sensitivity was 5 pg/mL. The inter- and intra-assay coefficients of variation were <7% and < 4.5%, respectively. Statistical Analysis Categoric data were expressed as number and percentage, and numerical data as mean SEM. Student t test and c2 test were used when appropriate. Significance was set at .05. All statistical analysis was performed with use of Sigmastat for Windows, version 2.0 (Jandel Scientific Corporation, San Rafael, CA). RESULTS Relevant clinical data, basically body mass index (21.5 2.9kg/m2 vs. 22.04 2.3 kg/m2) and age (25.4 4 yrs vs. 23.8 3.9 yrs), from both groups of oocyte donors were similar. Both groups showed similar cycle outcomes in terms of duration of the stimulation (8.5 1.1 vs. 8.9 1.2 days; P¼.29), total dose of rFSH (1,307 235 IU vs. 1,377 234 IU; P¼.35), peak serum E2 (2,537 1,032 vs. 2,095 979 pg/mL; P¼.17), serum P levels the day Fertility and Sterility
of hCG/GnRHa administration (0.8 0.5 ng/mL vs. 0.8 0.3 ng/mL; P¼78), and oocytes retrieved (14 4 vs. 17 8; P¼.12). We did find differences in the duration of the luteal phase: The period to menstrual onset in the non-hCG group was significantly shorter (10.2 1.1 days vs. 5.2 1.6 days; P<.001). Also, in the routine control we do to all our donors 1 week after the ovarian puncture, 42% of those who received hCG reported subjective complaints (mostly abdominal discomfort), whereas this percentage was 0% in those who received GnRH agonist to trigger ovulation. No OHSS was observed in either cohort. We did not find any differences in plasma levels of VEGF in either group, whether it was the day of hCG/GnRHa or the day of ovum pick-up (Table 1). However, a significant reduction in follicular fluid VEGF concentration was observed in those follicles coming from donors that received GnRHa instead of hCG (1,666 53 [95% confidence interval (CI) 1,267–1,946] pg/mL vs. 1,207 135 [95% CI 436–2,117] pg/mL; P<.001). DISCUSSION To our knowledge, this is the first report investigating the differential secretion of a soluble vascular mediator (VEGF) when final oocyte maturation is induced by either hCG or a single bolus of GnRHa. The significantly lower concentrations of VEGF in the follicular fluid of patients who received GnRHa have direct clinical consequences to prevent OHSS. Vascular endothelial growth factor is the key molecule among the different vascular mediators released from the ovaries and other tissues in response to hCG (3–7, 9). The long half-life of hCG of around 7 days, due to the continuous stimulus and liberation of vasoactive mediators, may complicate some assisted reproduction patients with OHSS, a potentially life-threatening consequence (13). Therefore, the search for a surrogate for hCG has been crucial. Clinical empirical observations had previously confirmed that finding a surrogate for hCG that was able to induce final oocyte maturation was feasible and safe. For instance, exogenous LH could be an option, but impractical due to the high cost (13). An alternative, in those patients undergoing COH with the antagonist—so the pituitary is not desensitized—is a bolus of GnRH agonist. Preliminary observations confirmed that the number of oocytes retrieved, fertilization, and embryo quality were unaffected (10). However, some controversy was raised, because implantation and pregnancy rates seemed to be diminished (11–13), although not all authors agreed (14). The fact that using this protocol in donors did not affect recipients’ outcome clarified that the hypothetic reduction in cycle outcome was related to luteal support, an area that needs further research. Previous research by Babayof et al. (15) regarding VEGF differential regulation by hCG or GnRH agonist did not find
1527
TABLE 1 Plasma and follicular fluid VEGF concentration (pg/mL). hCG n [ 19 Plasma, day of hCG or GnRHa Plasma, day of egg retrieval Follicular fluid
GnRHa n [ 20
P value
158 26 (44–326)
173 23 (63–314)
NS
193 28 (81–381)
219 27 (81–411)
NS
1,666 53 (1,267–1946)
1,207 135 (436–2,117)
< .001
Note: Values are presented as mean SEM (95% confidence interval). GnRH ¼ GnRH agonist. Cerrillo. VEGF production after hCG or GnRH agonist. Fertil Steril 2009.
significant differences in serum. The facts that VEGF was measured only in serum—and not in plasma—and that follicular fluid VEGF concentrations were not evaluated could explain their findings. Because VEGF is secreted by granulosa cells, the ideal biologic sample to evaluate it would be follicular fluid, and indeed, differences were significant. A limitation of the present work is that we used two different protocols (standard long and antagonist) in our donors. However, this should not be a major drawback, because similar concentrations of VEGF have been found in serum and follicular fluid of women undergoing these two protocols (16). Obviously, owing to the limited sample size, we cannot exclude other causes apart from the reduced follicular fluid VEGF concentration that may contribute to the absence of OHSS in this series. To conclude, we have demonstrated that intrafollicular VEGF concentration is reduced when final oocyte maturation is induced by a single bolus of GnRH agonist instead of hCG, which may cause luteolysis and thus contribute to reducing the incidence of OHSS. This observation, together with a shorter duration of the luteal phase, a minimal discomfort for the donor, and the previous evidence that oocyte/embryo quality is not affected, should help us to implement this approach as the routine standard protocol in oocyte donors. Maria Cerrillo, M.D.a Sara Rodrıguez, Ph.D.a Mercedes Mayoral, M.D.a Alberto Pacheco, Ph.D.a Javier Martınez-Salazar, M.D.a Juan A. Garcia-Velasco, M.D.a,b a IVI-Madrid; and b Rey Juan Carlos University, Madrid, Spain REFERENCES 1. Navot D, Bergh PA, Laufer N. Ovarian hyperstimulation syndrome in novel reproductive technologies: prevention and treatment. Fertil Steril 1992;58:249–61. 2. Balasch J, Fabregues F, Arroyo V. Peripheral arterial vasodilation hypothesis: a new insight into pathogenesis of ovarian hyperstimulation syndrome. Hum Reprod 1998;13:2718–30. 3. McClure N, Healy DL, Rogers PA, Sullivan J, Beaton L, Haning RV. Vascular endothelial growth factor as capillary permeability agent in ovarian hyperstimulation syndrome. Lancet 1994;344:235–6.
1528
Cerrillo et al.
Correspondence
4. Abramov Y, Barak V, Nisman B, Schenker JG. Vascular endothelial growth factor plasma levels correlate to the clinical picture in severe ovarian hyperstimulation syndrome. Fertil Steril 1997;68:133–7. 5. Pellicer A, Albert C, Mercader A, Bonilla-Musoles F, Remohi J, Simon C. The pathogenesis of ovarian hyperstimulation syndrome: in vivo studies investigating the role of interleukin (IL)-1b, IL-6, and vascular endothelial growth factor (VEGF). Fertil Steril 1999;71:482–9. 6. Gomez R, Simon C, Remohi J, Pellicer A. Vascular endothelial growth factor receptor-2 activation induces vascular permeability in hyperstimulated rats, and this effect is prevented by receptor blockade. Endocrinology 2002;143:4339–48. 7. Gomez R, Simon C, Remohi J, Pellicer A. Administration of moderate and high doses of gonadotropins to female rats incesaes ovarian vascular endomthelial growth factor (VEGF) ans VEGF receptor 1 expression that is asssociated to vascular hypermeability. Biol Reprod 2003;68:2164–71. 8. Villasante A, Pacheco A, Pau E, Ruiz A, Pellicer A, Garcia-Velasco JA. Soluble vascular endothelial-cadherin levels correlate with clinical and biological aspects of severe ovarian hyperstimulation syndrome. Hum Reprod 2008;23:662–7. 9. Soares S, Gomez R, Simon C, Garcia-Velasco J, Pellicer A. Targeting the vascular endothelial growth factor system to prevent ovarian hyperstimulation syndrome. Hum Reprod Update 2008;14:321–33. 10. Acevedo B, Gomez-Palomares JL, Ricciarelli MD, Herna´ndez E. Triggering ovulation with gonadotropin-releasing hormone agonist does not compromise embryo implantation rates. Fertil Steril 2006;86:1682–7. 11. Engmann L, Siano L, Schmidt D, Nulsen J, Maier D, Benadiva C. GnRH agonist to induce oocyte maturation during IVF in patients at high risk of OHSS. Reprod Biomed Online 2006;13:639–44. 12. Griesenger G, Diedrich K, Devroey P, Kolibianakis E. GnRH agonist for triggering final oocyte maturation in the GnRH antagonist ovarian hyperstimulation protocol: a systematic review and meta-analysis. Hum Reprod Update 2006;12:159–68. 13. Kol S, Solt I. GnRH agonist for triggering final oocyte maturation in patients at risk of ovarian hyperstimulation syndrome: still a controversy? J Assist Reprod Genet 2008;25:63–6. 14. Engman L, DiLuigi A, Schmidt D, Nulsen J, Maier D, Benadiva C. The use of gonadotropin-releasing hormone (GnRH) agonist to induce oocyte maturation after cotreatment with GnRH antagonist in high-risk patients undergoing in vitro fertilization prevents the risk of ovarian hyperstimulation syndrome: a prospective randomized controlled study. Fertil Steril 2008;89:84–91. 15. Babayof R, Margalioth E, Huleihel M, Amash A, Zylber-Haran E, Gal M, et al. Serum inhibin A, VEGF and TNFa levels after triggering oocyte maturation with GnRH agonist compared with HCG in women with polycystic ovaries undergoing IVF treatment: a prospective randomized trial. Hum Reprod 2006;21:1260–5. 16. Asimakopoulos B, Ko¨ster F, Felberbaum R, Al-Hasani S, Diedrich K, Nikolettos N. Cytokine and hormonal profile in blood serum and follicular fluids during ovarian stimulation with the multidose antagonist or the long agonist protocol. Hum Reprod 2006;21: 3091–5.
Vol. 91, No. 4, Supplement, April 2009