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Dive into the research topics where Michel De Vos is active.

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Featured researches published by Michel De Vos.


The Lancet | 2014

Fertility preservation in women with cancer

Michel De Vos; Johan Smitz; Teresa K. Woodruff

Enhanced long-term survival rates of young women with cancer and advances in reproductive medicine and cryobiology have culminated in an increased interest in fertility preservation methods in girls and young women with cancer. Present data suggest that young patients with cancer should be referred for fertility preservation counselling quickly to help with their coping process. Although the clinical application of novel developments, including oocyte vitrification and oocyte maturation in vitro, has resulted in reasonable success rates in assisted reproduction programmes, experience with these techniques in the setting of fertility preservation is in its infancy. It is hoped that these and other approaches, some of which are still regarded as experimental (eg, ovarian tissue cryopreservation, pharmacological protection against gonadotoxic agents, in-vitro follicle growth, and follicle transplantation) will be optimised and become established within the next decade. Unravelling the complex mechanisms of activation and suppression of follicle growth will not only expand the care of thousands of women diagnosed with cancer, but also inform the care of millions of women confronted with reduced reproductive fitness because of ageing.


Reproductive Biomedicine Online | 2008

Prospectively randomized controlled trial of PGS in IVF/ICSI patients with poor implantation.

Christophe Blockeel; Valerie Schutyser; Anick De Vos; W. Verpoest; Michel De Vos; Catherine Staessen; Patrick Haentjens; Josiane Van der Elst; Paul Devroey

This randomized, controlled trial verifies whether patients with recurrent failed implantation benefit from preimplantation genetic diagnosis for aneuploidy, as compared with conventional assisted reproduction treatment procedures. Two hundred patients with recurrent failed implantation were randomized into two groups. A total of 139 patients underwent ovarian stimulation, and preimplantation genetic screening was performed in 72 patients. Analysis of chromosomes X, Y, 13, 16, 18, 21 and 22 was carried out using fluorescence in-situ hybridization in blastomeres of day-3 cleavage-stage embryos in the study group. The primary endpoint was implantation rate. Secondary endpoints were embryonic morphology and chromosomal status, number of transferred embryos and clinical pregnancy rate. With regard to the implantation rate, there was no significant difference between the study group (21.4%) and the control group (25.3%). The number of embryos transferred was significantly lower in the study group, namely 1.4 (SD 1.0) versus 2.1 (SD 1.0) in the control group (P < 0.05). The clinical pregnancy rate was not significantly different between the groups (25.0% in the study group versus 40.3% in the control group). It can be concluded that preimplantation genetic screening does not increase the implantation rates after IVF-intracytoplasmic sperm injection in women with repeated implantation failure.


Fertility and Sterility | 2011

Clinical outcome of non–hCG-primed oocyte in vitro maturation treatment in patients with polycystic ovaries and polycystic ovary syndrome

Michel De Vos; C. Ortega-Hrepich; Firas K. Albuz; L. Guzman; Nikolaos P. Polyzos; Johan Smitz; Paul Devroey

OBJECTIVE To compare clinical outcomes of fresh embryo transfer (ET) and vitrified-warmed ET in an artificial endometrial priming cycle in patients with polycystic ovaries (PCO) or polycystic ovary syndrome (PCOS) who underwent oocyte in vitro maturation (IVM) in non-hCG-primed cycles. DESIGN Prospective cohort study. SETTING University-based tertiary referral center. PATIENT(S) Thirty-nine consecutive patients <37 years old with PCO or PCOS, who underwent 73 cycles of immature oocyte retrieval. INTERVENTION(S) Immature oocyte collection after ovarian stimulation with a cumulative dose of 450 IU uFSH or highly purified hMG, but without hCG priming. IVM of oocytes followed by ET if endometrium thickness ≥ 6 mm. Embryo vitrification at the cleavage stage. ET in an artificial cycle. MAIN OUTCOME MEASURE(S) Implantation rate (IR) and clinical pregnancy rate (CPR). RESULT(S) Fresh ET after IVM resulted in an IR of 6.9% (5/72) per ET and a CPR of 9.4% (5/53). ET of vitrified-warmed IVM embryos in an artificial cycle resulted in significantly better outcomes (IR 21.9% [7/32] and CPR 31.8% [7/22] per ET). CONCLUSION(S) A non-hCG-primed IVM system in PCO or PCOS performs poorly when embryos are transfered in a fresh cycle. Transfer of vitrified-warmed IVM embryos in an artificial cycle leads to significantly improved clinical outcomes. These data illustrate that IVM embryos in PCO or PCOS have good survival rates and suggest that hCG may be needed to support endometrial receptivity in the fresh IVM cycle.


Human Reproduction | 2013

Heparin and cAMP modulators interact during pre-in vitro maturation to affect mouse and human oocyte meiosis and developmental competence

Hai-tao Zeng; Zi Ren; L. Guzman; X. Wang; Melanie L. Sutton-McDowall; Lesley J. Ritter; Michel De Vos; Johan Smitz; Jeremy G. Thompson; Robert B. Gilchrist

STUDY QUESTION Does heparin ablate the advantageous effects of cyclic adenosine mono-phosphate (cAMP) modulators during pre-in vitro maturation (IVM) and have a deleterious effect in standard oocyte IVM? SUMMARY ANSWER Heparin interrupts energy metabolism and meiotic progression and adversely affects subsequent development of oocytes under conditions of elevated cAMP levels in cumulus-oocyte complexes (COCs) after pre-IVM treatment with forskolin. WHAT IS KNOWN ALREADY In animal IVM studies, artificial regulation of meiotic resumption by cAMP-elevating agents improves subsequent oocyte developmental competence. Heparin has no effect on spontaneous, FSH- or epidermal growth factor (EGF)-stimulated meiotic maturation. STUDY DESIGN, SIZE, DURATION An in vitro cross-sectional study was conducted using immature mouse and human COCs. Depending on individual experimental design, COCs were treated during pre-IVM with or without heparin, in the presence or absence of forskolin and/or 3-isobutyl-1-methylxanthine (IBMX), and then COC function was assessed by various means. PARTICIPANTS/MATERIALS, SETTINGS, METHODS Forty-two women with polycystic ovaries (PCOs) or polycystic ovarian syndrome (PCOS) donated COCs after oocyte retrieval in a non-hCG-triggered IVM cycle. COCs were collected in pre-IVM treatments and then cultured for 40 h and meiotic progression was assessed. COCs from 21- to 24-day-old female CBA F1 mice were collected 46 h after stimulation with equine chorionic gonadotrophin. Following treatments, COCs were checked for meiotic progression. Effects on mouse oocyte metabolism were measured by assessing oocyte mitochondrial membrane potential using JC-1 staining and oocyte ATP content. Post-IVM mouse oocyte developmental competence was assessed by in vitro fertilization and embryo production. Blastocyst quality was evaluated by differential staining of inner cell mass (ICM) and trophectoderm (TE) layers. MAIN RESULTS AND THE ROLE OF CHANCE In the absence of heparin in pre-IVM culture, the addition of cAMP modulators did not affect human oocyte MII competence after 40 h. In standard IVM, heparin supplementation in pre-IVM did not affect MII competence; however, when heparin was combined with cAMP modulators, MII competence was significantly reduced from 65 to 15% (P < 0.05). In mouse experiments, heparin alone in pre-IVM significantly delayed germinal vesicle breakdown (GVBD) so that fewer GVBDs were observed at 0 and 1 h of IVM (P < 0.05), but not by 2 or 3 h of IVM. Combined treatment with IBMX and forskolin in the pre-IVM medium produced a large delay in GVBD such that no COCs exhibited GVBD in the first 1 h of IVM, and the addition of heparin in pre-IVM further significantly delayed the progression of GVBD (P < 0.05), in a dose-dependent manner (P < 0.01). Combined IBMX and forskolin treatment of mouse COCs during pre-IVM significantly increased mitochondrial membrane potential and ATP production in the oocyte at the end of pre-IVM (P < 0.05), and significantly improved fertilization, embryo development and quality (P < 0.05). However, heparin abolished the IBMX + forskolin-stimulated increase in mitochondrial membrane potential and ATP production (P < 0.05), and adversely affected embryonic cleavage, development rates and embryo quality (P < 0.05). This latter adverse combinational effect was negated when mouse COCs were collected in heparin and IBMX for 15 min, washed and then cultured for 45 min in IBMX and forskolin without heparin. LIMITATION, REASONS FOR CAUTION Experiments in mice found that heparin ablation of the advantageous effects of cAMP modulators during pre-IVM was associated with altered oocyte metabolism, but the mechanism by which heparin affects metabolism remains unclear. WIDER IMPLICATIONS OF THE FINDINGS This study has revealed a novel and unexpected interaction between heparin and cAMP modulators in pre-IVM in immature mouse and human oocytes, and established a means to collect oocytes using heparin while modulating oocyte cAMP to improve developmental potential.


Fertility and Sterility | 2012

Developmental capacity of in vitro–matured human oocytes retrieved from polycystic ovary syndrome ovaries containing no follicles larger than 6 mm

L. Guzman; C. Ortega-Hrepich; Firas K. Albuz; Greta Verheyen; Paul Devroey; Johan Smitz; Michel De Vos

OBJECTIVE To test the developmental competence of oocytes in a nonhCG-triggered in vitro maturation (IVM) system when oocyte-cumulus complexes (OCC) are retrieved from antral follicles with a diameter of <6 mm. DESIGN Prospective cohort study. SETTING Tertiary university-based referral center. PATIENT(S) From January 2010 to September 2011, 121 patients with polycystic ovaries/polycystic ovary syndrome underwent 239 IVM cycles in total. In 58 of these cycles (44 patients), all antral follicles had a diameter of <6 mm on the day of oocyte retrieval. INTERVENTION(S) NonhCG-triggered IVM of oocytes, fresh or vitrified/warmed embryo transfer (ET). MAIN OUTCOME MEASURE(S) Oocyte diameter, maturation rate, fertilization rate, embryo development and morphology, implantation rate, clinical pregnancy rate, ongoing pregnancy rate. RESULT(S) Oocyte retrieval yielded 16.7 OCC/cycle, and 50.8% of oocytes completed IVM. The mean oocyte diameter increased from 108.8 ± 4.3 μm to 111.9 ± 4.1 μm after IVM. Mean fertilization rate was 63.7%, and 45.4% of 2-pronuclei oocytes developed into a morphologically good-quality embryo on day 3 after intracytoplasmic sperm injection. Fresh ET resulted in two ongoing pregnancies (2/37; 5.4%). Deferred vitrified-warmed ET led to an ongoing pregnancy rate of 34.6% (9/24). Three healthy babies were born and eight pregnancies were still ongoing. CONCLUSION(S) Oocytes retrieved from follicles with a diameter of <6 mm grow during a 40-hour IVM culture can acquire full competence in vitro, as illustrated by their development into healthy offspring. Endometrial quality appears to be a crucial determinant of pregnancy after nonhCG-triggered IVM.


Archives of Gynecology and Obstetrics | 2013

Three decades after Gjonnaess's laparoscopic ovarian drilling for treatment of PCOS; what do we know? An evidence-based approach

Hatem Abu Hashim; Hesham Al-Inany; Michel De Vos; Herman Tournaye

BackgroundThe introduction of laparoscopic ovarian drilling (LOD) by Gjönnaess in 1984 as a substitute for ovarian wedge resection created opportunities for extensive research given its worldwide application for ovulation induction in women with polycystic ovary syndrome (PCOS).PurposeTo critically evaluate and summarize the current body of literature regarding the role of LOD for the management of PCOS entailing its different preoperative, operative and postoperative aspects. In addition, long-term efficacy, cost-effectiveness, patient preference and health-related quality of life issues will be evaluated together with other available alternatives of ovulation induction treatments.MethodsA PubMed search was conducted looking for the different trials, reviews and various guidelines relating to the role of LOD in the management of PCOS.ResultsLOD whether unilateral or bilateral is a beneficial second-line treatment in infertile women with clomiphene citrate (CC)-resistant PCOS. It is as effective as gonadotrophin treatment but without the risk of multiple pregnancy or ovarian hyperstimulation and does not require intensive monitoring. Increased responsiveness of the ovary to CC especially in patients who remain anovulatory following LOD is another advantage. Recent evidence suggests that relatively novel oral methods of ovulation induction, e.g. CC plus metformin, CC plus tamoxifen, rosiglitazone plus CC and aromatase inhibitors represent a successful alternative to LOD in CC-resistant PCOS. Meanwhile current evidence does not support LOD as a first-line approach in PCOS-related anovulation or before IVF.ConclusionLOD is currently recommended as a successful and economical second-line treatment for ovulation induction in women with CC-resistant PCOS.


Reproductive Biomedicine Online | 2012

Oestradiol valerate pretreatment in GnRH-antagonist cycles: a randomized controlled trial

Christophe Blockeel; Sara Engels; Michel De Vos; Patrick Haentjens; Nikolaos P. Polyzos; D. Stoop; Michel Camus; Paul Devroey

This randomized controlled trial analyses the ability to control the oocyte retrieval schedule of gonadotrophin-releasing hormone antagonist cycles through the administration of oestradiol valerate during the luteo-follicular transition period prior to the initiation of ovarian stimulation. Eighty-six women undergoing ovarian stimulation for IVF/intracytoplasmic sperm injection were enrolled in the study. The control group (n = 42) received a standard ovarian stimulation protocol. In the pretreatment group (n = 44), patients were administered oestradiol valerate at a daily dose of 2 · 2 mg from day 25 of the preceding cycle onwards, during 6–10 consecutive days, depending on the day of the week. The primary endpoint was the proportion of patients undergoing oocyte retrieval during a weekend day (i.e. Saturday or Sunday), which was significantly lower in the pretreatment group (1/37, 2.7%) compared with the control group (8/39, 20.5%; P value = 0.029). The clinical pregnancy rates per started cycle were similar in the pretreatment group (38.6%) compared with the control group (38.1%). Pretreatment with oestradiol valerate results in a significantly lower proportion of patients undergoing oocyte retrieval during a weekend day and can be a valuable tool for the organization of an assisted reproduction centre.


Fertility and Sterility | 2011

Administration of a gonadotropin-releasing hormone antagonist during the 3 days before the initiation of the in vitro fertilization/intracytoplasmic sperm injection treatment cycle: impact on ovarian stimulation. A pilot study

Christophe Blockeel; Arianna Riva; Michel De Vos; Patrick Haentjens; Paul Devroey

OBJECTIVE To investigate the impact on the number of cumulus-oocyte complexes (COC) when a 3-day course of GnRH antagonist treatment precedes the initiation of controlled ovarian stimulation with gonadotropins in a GnRH antagonist protocol for IVF/intracytoplasmic sperm injection (ICSI). DESIGN Randomized controlled trial. SETTING Tertiary referral center. PATIENT(S) Sixty-nine women undergoing controlled ovarian hyperstimulation for IVF/ICSI. INTERVENTION(S) The control group (n = 36) received a standard treatment with daily injections of recombinant FSH (rFSH), starting on day 2 of the cycle at a dose of 150-225 IU/day, and GnRH antagonists from cycle day 7 onward. In the pretreatment group (n = 33), a GnRH antagonist was administered from day 2 of the menstrual cycle onward during 3 consecutive days; thereafter controlled ovarian stimulation was initiated with the same protocol as used in the control group. MAIN OUTCOME MEASURE(S) The primary endpoint was the number of COCs at egg retrieval. RESULT(S) Both groups had comparable baseline characteristics. The duration of rFSH stimulation and consumption of gonadotropins were similar in both groups. The number of COCs was higher in the pretreatment group (12.8; SD, 7.8) compared with in the control group (9.9; SD, 4.9), although this increment was not significant (between-group difference of 2.9 [95% confidence interval {CI} -0.2 to 6.0]). The ongoing pregnancy rates per started cycle of 14/33 (42%) versus 12/36 (33%) for pretreatment versus control did not differ significantly (between-group difference, 9.1%; 95% CI, -13% to 30%). CONCLUSION(S) Among women under 36 years old, early follicular phase GnRH antagonist pretreatment in a fixed GnRH antagonist protocol results in a trend toward a higher number of retrieved oocytes but does not yield significantly higher pregnancy rates.


Reproductive Biology and Endocrinology | 2014

The effect of ovarian puncture on the endocrine profile of PCOS patients who undergo IVM.

C. Ortega-Hrepich; Nikolaos P. Polyzos; Ellen Anckaert; L. Guzman; Herman Tournaye; Johan Smitz; Michel De Vos

BackgroundTo examine whether ovarian puncture for immature oocyte retrieval and in-vitro maturation (IVM) has an effect on the endocrine profile of patients with polycystic ovary syndrome (PCOS).MethodsTwenty-two consecutive patients with PCOS undergoing IVM treatment were included. Serum anti-Müllerian hormone (AMH), sex hormone-binding globulin (SHBG), total testosterone (TT) and luteinized hormone (LH) levels were analyzed at the start of the cycle, on the day of immature oocyte retrieval (OR) and at fixed intervals thereafter, for up to three months after OR.ResultsFive days after OR circulating AMH, TT, calculated free testosterone (FTc), and LH levels were significantly reduced and circulating SHBG was significantly increased. Two weeks after OR, TT, FTc and LH remained reduced, whereas circulating AMH and SHBG levels recovered to pre-puncture values. Three months after OR, all circulating hormone levels had recovered to baseline values.ConclusionOvarian puncture for the retrieval of immature oocytes and IVM in patients with PCOS has a significant impact on the ovarian endocrine profile, but this impact is brief and transient.


Fertility and Sterility | 2011

IVM media are designed specifically to support immature cumulus-oocyte complexes not denuded oocytes that have failed to respond to hyperstimulation

Robert B. Gilchrist; Michel De Vos; Johan Smitz; Jeremy G. Thompson

We wish to express concern about the design, analysis, and conclusions reported in the article by Moschini et al. (1). This study compares the efficiency of an oocyte IVM medium (Medicult) to a cleavage-stage embryo culture medium (Sage IVF), for the in vitro maturation (IVM) of denuded oocytes that have failed to respond to gonadotropins in a standard IVF cycle (rescue IVM). We have a number of objections to this study.

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Johan Smitz

Vrije Universiteit Brussel

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Paul Devroey

Vrije Universiteit Brussel

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Herman Tournaye

Vrije Universiteit Brussel

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C. Ortega-Hrepich

Vrije Universiteit Brussel

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Greta Verheyen

Vrije Universiteit Brussel

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Patrick Haentjens

Vrije Universiteit Brussel

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