An improved IVM method for cumulus-oocyte complexes from small follicles in polycystic ovary syndrome patients enhances oocyte competence and embryo yield.

STUDY QUESTION: Are meiotic and developmental competence of human oocytes from small (2-8 mm) antral follicles improved by applying an optimized IVM method involving a prematuration step in presence of C-Type Natriuretic Peptide (CNP) followed by a maturation step in presence of FSH and Amphiregulin (AREG)? SUMMARY ANSWER: A strategy involving prematuration culture (PMC) in the presence of CNP followed by IVM using FSH + AREG increases oocyte maturation potential leading to a higher availability of Day 3 embryos and good-quality blastocysts for single embryo transfer. WHAT IS KNOWN ALREADY: IVM is a minimal-stimulation ART with reduced hormone-related side effects and risks for the patients, but the approach is not widely used because of an efficiency gap compared to conventional ART. In vitro systems that enhance synchronization of nuclear and cytoplasmic maturation before the meiotic trigger are crucial to optimize human IVM systems. However, previous PMC attempts have failed in sustaining cumulus-oocyte connections throughout the culture period, which prohibited a normal cumulus-oocyte communication and precluded an adequate response by the cumulus-oocyte complex (COC) to the meiotic trigger. STUDY DESIGN, SIZE, DURATION: A first prospective study involved sibling oocytes from a group of 15 patients with polycystic ovary syndrome (PCOS) to evaluate effects of a new IVM culture method on oocyte nuclear maturation and their downstream developmental competence. A second prospective study in an additional series of 15 women with polycystic ovaries characterized and fine-tuned the culture conditions. PARTICIPANTS/MATERIALS, SETTING, METHODS: Fifteen women with PCOS (according to Rotterdam criteria) underwent IVM treatment after 3-5 days of highly purified human menopausal gonadotropin (HP-hMG) stimulation and no human chorionic gonadotropin (hCG) trigger before oocyte retrieval. A first study was designed with sibling oocytes to prospectively evaluate the impact of an IVM culture method: 24 h PMC with CNP + 30 h IVM with FSH and AREG, on embryo yield, in comparison to the standard (30 h) IVM clinical protocol (Group I, n = 15). A second prospective study was performed in 15 women with polycystic ovaries, to characterize and optimize the PMC conditions (Group II, n = 15). The latter study involved the evaluation of oocyte meiotic arrest, the preservation of cumulus-oocyte transzonal projections (TZPs), the patterns of oocyte chromatin configuration and cumulus cells apoptosis following the 24 and 46 h PMC. Furthermore, oocyte developmental potential following PMC (24 and 46 h) + IVM was also evaluated. The first 20 good-quality blastocysts from PMC followed by IVM were analysed by next generation sequencing to evaluate their aneuploidy rate. MAIN RESULTS AND THE ROLE OF CHANCE: PMC in presence of CNP followed by IVM using FSH and AREG increased the meiotic maturation rate per COC to 70%, which is significantly higher than routine standard IVM (49%; P ≤ 0.001). Hence, with the new system the proportion of COCs yielding transferable Day 3 embryos and good-quality blastocysts increased compared to routine standard IVM (from 23 to 43%; P ≤ 0.001 and from 8 to 18%; P ≤ 0.01, respectively). CNP was able to prevent meiosis resumption for up to 46 h. After PMC, COCs had preserved cumulus-oocyte TZPs. The blastocysts obtained after PMC + IVM did not show increased aneuploidy rates as compared to blastocysts from conventional ART. LIMITATIONS REASONS FOR CAUTION: The novel IVM approach in PCOS patients was tested in oocytes derived from small antral follicles which have an intrinsically low developmental potential. Validation of the system would be required for COCs from different (larger) follicular sizes, which may involve further adjustment of PMC conditions. Furthermore, considering that this is a novel strategy in human IVM treatment, its global efficiency needs to be confirmed in large prospective randomized controlled trials. The further application in infertile patients without PCOS, e.g. cancer patients, remains to be evaluated. WIDER IMPLICATIONS OF THE FINDINGS: The findings of this pilot study suggest that the efficiency gap between IVM and conventional IVF can be reduced by fine-tuning of the culture methods. This novel strategy opens new perspectives for safe and patient-friendly ART in patients with PCOS. STUDY FUNDING/COMPETING INTEREST(S): IVM research at the Vrije Universiteit Brussel has been supported by grants from: the Institute for the Promotion of Innovation by Science and Technology in Flanders (Agentschap voor Innovatie door Wetenschap en Technologie-IWT, project 110680); the Fund for Research Flanders (Fonds Wetenschappelijk Onderzoek-Vlaanderen-FWO, project G.0343.13), the Belgian Foundation Against Cancer (HOPE project, Dossier C69). The authors have no conflicts of interest.

Follicle culture in reproductive toxicology: a tool for in-vitro testing of ovarian function?

Public opinion and official bodies place great emphasis on the reduction, refinement and replacement of the use of laboratory animals in testing protocols. In the field of toxicology, major efforts are being made to commit to this goal. The testing of reproductive function is currently still performed by in-vivo tests, mainly in rodents. In the past, follicle culture models were developed for the in-vitro production of mature oocytes and used to study the process of folliculogenesis and oogenesis in vitro. These culture systems might be able to acquire a place in fertility testing, replacing in-vivo studies for ovarian function and female gamete quality testing. The proficiency data from a well-characterized follicle culture system suggest that this bioassay might be of potential use for in-vitro screening of xenobiotic substances affecting ovarian function and fertility.

Fluorescent probes allow rapid and precise recording of follicle density and staging in human ovarian cortical biopsy samples.

OBJECTIVE: To develop rapid and reliable techniques for determining follicle content, viability, and morphologic features in an ovarian cortical biopsy specimen. DESIGN: Prospective laboratory study. SETTING: Academic research institution. PATIENT(S): Consenting patients undergoing laparoscopic surgery for nonovarian disease. INTERVENTION(S): Ovarian cortical biopsy specimens were stained by using fluorescent probes and conventional histologic stains. Observations were made by using light, fluorescent, and confocal laser microscopy. MAIN OUTCOME MEASURE(S): Density, cellular viability, and morphologic features of ovarian follicles. RESULT(S): After 45 minutes of incubation of ovarian cortical tissue with calcein AM, follicles were visualized by fluorescent microscopy and counted. Ten minutes of exposure is sufficient to stain all cell nuclei with the PicoGreen probe. Subsequent confocal microscopy allows quantification of follicle density and reveals follicle morphology in the optical sections. Follicle density as assessed by using these rapid methods was concordant with the number of units counted in conventionally stained histologic sections. CONCLUSION(S): Use of fluoroprobes for mitochondrial and DNA staining allows rapid evaluation of follicle density in ovarian tissue.

Analysis of the bleeding pattern in assisted reproduction cycles with luteal phase supplementation using vaginal micronized progesterone.

This study was designed to determine the effects of a vaginal micronized progesterone preparation on bleeding patterns and pregnancy outcomes after in-vitro fertilization and intracytoplasmic sperm injection (IVF-ICSI). The study population consisted of 149 consecutive women who had undergone IVF-ICSI using 'long-protocol' stimulation with buserelin-human menopausal gonadotrophin (HMG). A retrospective chart analysis of computerized medical records was undertaken. Vaginal progesterone (200 mg three times daily) was begun the day before oocyte retrieval and continued for a minimum of 16-19 days following human chorionic gonadotrophin (HCG) administration. Occurrence of bleeding following HCG injection, pregnancy rate and outcomes, and serum concentrations of oestradiol were measured. Women undergoing IVF and embryo transfer with ICSI and using vaginal progesterone for luteal support had normal luteal phase lengths (day of HCG minus day of onset of bleeding). In the absence of pregnancy, bleeding occurred after 19.2 +/- 3.9 days (mean +/- SD). Out of the pregnant group only three women bled within 19 days of HCG administration: two had biochemical pregnancies which spontaneously vanished and one evolved to term. The results reflect the normal bleeding pattern to be expected when vaginal progesterone is used for luteal support in IVF and embryo transfer, an approach whose efficacy has been amply proven. No shortened luteal phases were observed using vaginally administered progesterone.

Timed analysis of the nuclear maturation of oocytes in early preantral mouse follicle culture supplemented with recombinant gonadotropin.

OBJECTIVE: To analyze the effects of combined FSH and variable doses of LH on the nuclear maturity and capacity to resume meiosis in oocytes from preantral follicles from prepubertal mice. DESIGN: Prospective, randomized, and controlled in vitro laboratory experiment. SETTING: Academic research environment. INTERVENTION(S): Meiosis was studied after somatic cell removal or after stimulation with hCG plus epidermal growth factor in three culture conditions: maturation medium with FSH alone and with two different doses of LH. MAIN OUTCOME MEASURE(S): The nuclear maturation of the oocytes and the E2, progesterone, and alpha-specific inhibin content of the conditioned medium. RESULT(S): Somatic cell removal and hormonal stimulation were equally effective in inducing germinal vesicle breakdown, but the hormonal stimulus was essential for the completion of meiosis, which was maximal (70%) on day 13 of culture. Continuous addition of LH to FSH during the oocytes' growth made them more prone to spontaneous resumption of meiosis I but resulted in a higher proportion of oocytes reaching the completion of meiosis. Estradiol and progesterone measurements demonstrated that the presence of LH influences luteinization. CONCLUSION(S): In contrast to oocytes grown in vivo, cumulus cell removal by itself is an insufficient stimulus for oocytes cultured in vitro to complete meiosis. Timed stimulation with hCG and epidermal growth factor increases nuclear maturation rates. A maximum number of metaphase II oocytes are obtained after a 13-day in vitro growth period when LH is added to the maturation medium.