Correlations between follicular fluid steroid analysis and maturity and cytogenetic analysis of human oocytes that remained unfertilized after in vitro fertilization

LH supplementation of ovarian stimulation protocols influences follicular fluid steroid composition contributing to the improvement of ovarian response in poor responder women

In this prospective study, we evaluated the steroid levels in 111 follicular fluids (FF) collected from 13 women stimulated with FSH monotherapy and 205 FF collected from 28 women stimulated with FSH + LH because of a previous history of hypo-responsiveness to FSH. Steroid levels were measured by HPLC/MS–MS and related to ovarian stimulation protocol, oocyte maturity, fertilization and quality of blastocysts, after individually tracking the fate of all retrieved oocytes. 17-Hydroxy-Progesterone, Androstenedione, Estradiol and Estrone were significantly higher in the FSH + LH protocol. Progesterone, 17-Hydroxy-Progesterone and Estradiol were more expressed in FF yielding a mature oocyte (p < 0.01) in the FSH + LH protocol. FF Progesterone concentration was correlated with the rate of normal fertilization in the FSH protocol. None of the FF steroids measured were associated with blastocyst quality and achievement of pregnancy. Our results indicate that LH supplementation in hypo-responsive women modifies ovarian steroid production, mimicking physiological production better and likely contributing to an improved ovarian response. Employing a correct methodological procedure to evaluate the relationship between FF steroid hormones and assisted reproduction outcomes, our study reveals that some steroids in single follicles may be helpful in predicting oocyte maturity and fertilization.

Steroid profiles by liquid chromatography-mass spectrometry of matched serum and single dominant ovarian follicular fluid from women undergoing IVF

RESEARCH QUESTION

Can IVF outcomes be predicted from the steroid profile generated by liquid chromatography-mass spectrometry (LC-MS/MS) from follicular fluid collected from a single dominant follicle and serum after ovarian stimulation.

DESIGN

Prospective observational cohort study in which serum and follicular fluid were collected from women and used to generate steroid profiles by LC-MS/MS. A total of 93 consecutive women enrolled for IVF treatment were recruited at the Fertility Unit, Royal Prince Alfred Women and Babies Hospital, Sydney between September 2014 and July 2015. Baseline and serum levels at oocyte retrieval, as well as follicular fluid samples from the largest single antral follicle, were collected. All samples underwent steroid analysis within a single batch to measure progesterone (P4), oestradiol (E2), oestrone (E1), dehydroepiandrosterone (DHEA), androstenedione (A4), testosterone (T), dihydrotestosterone (DHT), and 3 α, 5α androstanediol (3α-diol) and 3β, 5α androstanediol (3β-diol).

RESULTS

P4, E2, E1, A4, T, DHEA and A4 were detectable in all baseline serum levels, at oocyte retrieval and in follicular fluid samples, whereas DHT, 3α-diol and 3β-diol were only detectable in a minority of samples. The most consistent predictor of pre-transfer (number of follicles >14mm in diameter, oocytes retrieved or fertilized, day-5 blastocysts) outcomes was baseline serum anti-Müllerian hormone. In follicular fluid, E2 was a negative predictor of the number of oocytes retrieved and the number of day-5 blastocysts but no follicular fluid steroids predicted pregnancy outcome.

CONCLUSIONS

None of the nine steroids measured in follicular fluid predicted pregnancy outcome in women undergoing IVF.

Exploratory study of the association of steroid profiles in stimulated ovarian follicular fluid with outcomes of IVF treatment

Steroid concentrations in stimulated follicular fluid (sFF) samples have been linked to the quality of oocytes used in IVF treatments. Most of the published studies focused on evaluating the association of the IVF outcomes with only a few of the steroids, measured by immunoassays (IA). We performed a treatment outcome, prospective cohort study using stimulated FF sampled from 14 infertile women undergoing IVF treatment; single oocyte was used per IVF cycle. Fourteen endogenous steroids were analyzed in 22 ovarian follicle aspirations, which corresponded to the embryos used in the IVF. Ten oocytes were associated with live birth (LB) and 12 with no pregnancy (NP). Steroids were analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods. Differences in distribution of concentrations in association with the pregnancy outcome (LB or NP), and receiver operating characteristic (ROC) curves analysis were performed for the entire cohort and for within-women data. The predominant androgen and estrogen in stimulated sFF were androstenedione (A4) and estradiol (E2), respectively. Lower concentrations of pregnenolone (Pr), lower ratios of A4/ dehydroepiandrosterone (DHEA), testosterone (Te)/DHEA, and greater ratios of E2/Te, and estrone/A4 were observed in sFF samples associated with LB. Among the oocytes associated with NP, in four out of 12 samples total concentration of androgens was above the distribution of the concentrations in the oocytes corresponding to the LB group. Observations of the study indicated increased consumption of precursors and increased biosynthesis of estrogens in the follicles associated with LB. Our data suggest that potentially steroid profiles in sFF obtained during oocyte retrieval may serve as biomarkers for selection of the best embryo to transfer after IVF.

Liquid chromatography-tandem mass spectrometry applications in endocrinology

Liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been recognized as a primary methodology for the accurate analysis of endogenous steroid hormones in biological samples. This review focuses on the use of LC-MS/MS in clinical laboratories to assist with the diagnosis of diverse groups of endocrine and metabolic diseases. Described analytical methods use on-line and off-line sample preparation and analytical derivatization to enhance analytical sensitivity, specificity, and clinical utility. Advantages of LC-MS/MS as an analytical technique include high specificity, possibility to simultaneously measure multiple analytes, and the ability to assess the specificity of the analysis in every sample. All described analytical methods were extensively validated, utilized in routine diagnostic practice, and were applied in a number of clinical and epidemiological studies, including a study of the steroidogenesis in ovarian follicles.

Steroid Profiles in Ovarian Follicular Fluid from Regularly Menstruating Women and Women after Ovarian Stimulation

Background: Information on the concentrations of steroids in ovarian follicular fluid (FF) from regularly menstruating (RM) women has been limited because of the absence of methods for the simultaneous quantification of multiple steroids in small volumes of FF. We studied steroid profiles in FF during the early follicular phase of the menstrual cycle and after ovarian stimulation for in vitro fertilization (IVF), and compared concentrations with published values obtained by immunoassay (IA).

Methods: We used liquid chromatography–tandem mass spectrometry (LC-MS/MS) to measure 13 steroids in 40-μL aliquots of FF samples from 21 RM women and from 5 women after ovarian stimulation for IVF. Relationships between concentrations of steroids and their ratios (representations of the enzyme activities) were evaluated within and between subgroups.

Results: The concentrations of testosterone (Te), androstenedione (A4), and estradiol (E2) measured by LC-MS/MS were lower than those previously reported in studies with IAs. In RM women, androgens were the most abundant class of steroids, with A4 being the major constituent. The concentrations of 17-hydroxyprogesterone (17OHP), total androgens, and estrogens were 200- to 1000-fold greater in FF than in serum. Compared with RM women, FF samples from women undergoing ovarian stimulation had significantly higher concentrations of E2 (P = 0.021), pregnenolone (P = 0.0022), 17OHP (P = 0.0007), and cortisol (F) (P = 0.0016), and significantly higher ratios of F to cortisone (P = 0.0006), E2 to estrone (P = 0.0008), and E2 to Te (P = 0.0013).

Conclusions: The data provide the first MS-based concentration values for 13 steroids in ovarian FF from RM women, from estrogen- and androgen-dominant follicles, and from women after ovarian stimulation for IVF.

Association of cumulus–oocyte complexes with the intrafollicular levels of a blood proten inBubalus bubalis

The protein pattern of the follicular fluid (FF) and the ultrastructure of the inner cumulus–oocyte complex (COC) has been analysed in single antral follicles (n= 146) of buffaloB. Bubalisovaries. The protein population of FF was fractionated by SDS-PAGE; the resulting pattern was Coomassie stained and processed for densitometry. Comparartive analysis of sera and autologous FFs showed a marked difference in the level (measured as the percentage of total proteins) of one 21 kDa polypeptide band, called ‘L’. Concentration of L, which was mainly higher in the serum (2.05 ± 1.5%) than in the surrounding FF(0.98 ± 0.94%), fluctuated widely in fluids from the in the same ovary. On gel filtration of FF and SDS-PAGE of ther factions collected, the L polypeptide was found and eluted together with a 36 kDa polypeptide, called ‘H’, with an exclusion volume lower than that of albumin. The levels of both polypeptides in the eluted fractions were measured by gel densitometry and the same ratio H/L was found (2:1). These data suggest that H and L are subunits of a complex high-molecular-weight protein. The presence of L levels in male sera comparable to those detected in females indicates that this putative protein does not originate in the ovary but is transported from the blood. Moreover, a correlation between the increase in the percentage of Lf (calculated as %L in FF/%L in serum) and atresia was observed. COCs (n= 86) obtained during the collection of the single FF samples were processed for transmission electron microscopy. The ultrastructure of each COC was compared with the SDS-PAGE data of the associated FF. Healthy COCs were found to be related to very low levels of Lf (between 0 and 14% of those measured in serum). COCs with an early atretic ultrastructure undetectable at the dissection microscope, were associated with FFs having Lf levels between 24% and 60%; advanced atresia was associated with Lf values up to 70%. Finally, the acrosome reaction of buffalo precapacitated spermatozoain vitrowas monitored by adding one volume of FF with high (FF +; Lf = 80%) or undetectable (FF - ) values of Lf to the sperm suspension. It was found that 96.2% of spermatozoa treated with FF - showed a normal acrosome reaction, without any change in their motility pattern; spermatozoa treated with FF +, in contrast, exhibited poor motility, and only 66.4% of them underwent the acrosome reaction. The ionophore A23187, in a control experiment, resulted in lower percentages of acrosome reactions (38%). In conclusion, our results suggest that enhanced influx of L from serum into the follicle antrum causes an increase in the polypeptide level in FF. This might be due to a loss of selectivity in the blood-follicle barrier of early atretic follicles. The use of the L polypeptide as a biochemical marker for identifying the earlier stage of follicular atresia is proposed.

Gender effects on the incidence of aneuploidy in mammalian germ cells

Aneuploidy occurs in 0.3% of newborns, 4% of stillbirths, and more than 35% of all human spontaneous abortions. Human gametogenesis is uniquely and gender-specific susceptible to errors in chromosome segregation. Overall, between 1% and 4% of sperm and as many as 20% of human oocytes have been estimated by molecular cytogenetic analysis to be aneuploid. Maternal age remains the paramount aetiological factor associated with human aneuploidy. The majority of extra chromosomes in trisomic offspring appears to be of maternal origin resulting from nondisjunction of homologous chromosomes during the first meiotic division. Differences in the recombination patterns between male and female meiosis may partly account for the striking gender- and chromosome-specific differences in the genesis of human aneuploidy, especially in aged oocytes. Nondisjunction of entire chromosomes during meiosis I as well as premature separation of sister chromatids or homologues prior to meiotic anaphase can contribute to aneuploidy. During meiosis, checkpoints at meiotic prophase and the spindle checkpoint at M-phase can induce meiotic arrest and/or cell death in case of disturbances in pairing/recombination or spindle attachment of chromosomes. It has been suggested that gender differences in aneuploidy may result from more permissive checkpoints in females than males. Furthermore, age-related loss of chromosome cohesion in oocytes as a cause of aneuploidy may be female-specific. Comparative data about the susceptibility of human male and female germ cells to aneuploidy-causing chemicals is lacking. Increases of aneuploidy frequency in sperm have been shown after exposure to therapeutic drugs, occupational agents and lifestyle factors. Conversely, data on oocyte aneuploidy caused by exogenous agents is limited because of the small numbers of oocytes available for analysis combined with potential maternal age effects. The vast majority of animal studies on aneuploidy induction in germ cells represent cause and effect data. Specific studies designed to evaluate possible gender differences in induction of germ cell aneuploidy have not been found. However, the comparison of rodent data available from different laboratories suggests that oocytes are more sensitive than male germ cells when exposed to chemicals that effect the meiotic spindle. Only recently, in vitro experiments, analyses of transgenic animals and knockdown of expression of meiotic genes have started to address the molecular mechanisms underlying chromosome missegregation in mammalian germ cells whereby striking differences between genders could be shown. Such information is needed to clarify the extent and the mechanisms of gender effects, including possible differential susceptibility to environmental agents.

The occurrence of aneuploidy in human: lessons from the cytogenetic studies of human oocytes

During the last 4 decades, the cytogenetic investigation of human oocytes has never stopped to progress, according to the advents of new technologies. Both karyotyping and molecular cytogenetic studies have been reported to date, providing a large body of data on the incidence and the distribution of chromosomal abnormalities in human female gametes. However, these studies display a great variability in results, which may be essentially attributable to the limitations of these techniques when applied to human oocytes. The most relevant analysis have led to the estimate that 15-20% of human oocytes present chromosome abnormalities, and they have emphasized the implication of both whole chromosome nondisjunction and chromatid separation in the occurrence of aneuploidy in human oocytes. The effect of advanced maternal age on the incidence of aneuploidies in human oocytes has also been clearly evidenced by recent reports based on large sample of oocytes or polar bodies, whereas most of initial studies have failed to confirm any relationship between maternal age and aneuploidy in human oocytes.

Localization and gene expression of steroid sulfatase by RT-PCR in cumulus cells and relationship to serum FSH levels observed during in vitro fertilization

Background

The purpose of this study was to localize the expression of steroid sulfatase (STS) in cumulus cells and to determine the relationship between STS mRNA expression and the serum levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol and progesterone.

Methods

The subject group included 49 women (29 to 44 years old) for whom in vitro fertilization treatment was indicated. All subjects gave informed consent. One hundred fourteen samples of cumulus-oocyte complex (COC) were obtained under microscopic observation. Part of the COC was stained by STS antibody. RNA was extracted by phenol-chloroform method and real-time PCR was performed. Serum of each patient was collected and was measured by ELISA.

Results

Some of the cumulus samples were stained by STS antibody. The expression of STS mRNA in all samples was confirmed by quantitative RT-PCR. Although there was no significant correlation between the level of STS mRNA and the serum levels of estradiol, progesterone and LH, there was a statistically significant negative correlation between the level of STS mRNA expression and the serum level of FSH (n = 105, p = 0.018, r = -0.22).

Conclusion

These results have demonstrated for the first time the expression of STS in cumulus cells by immunohistological stainings and real-time RT-PCR. STS expression in cumulus cells may be related to the control of the local steroidal environment in the oocyte. Serum FSH may control STS mRNA expression from the results of RT-PCR, although the correlation was low.

Reduction of progesterone receptor expression in human cumulus cells at the time of oocyte collection during IVF is associated with good embryo quality

BACKGROUND

It has been reported that the progesterone receptor (PR) level is transiently increased within the follicle by LH stimulation and controls cumulus cells in follicles and oocyte maturation. The purpose of this study was to predict developmental competence of human oocytes during IVF via analysis of PR in cumulus cells surrounding mature oocytes.

METHODS

Prior to oocyte retrieval, the follicular diameter was measured and follicular fluid was collected from each mature follicle. Cumulus cells were manually separated from the oocyte-cumulus complex under a microscope. PR and PR mRNA were assessed by immunohistochemistry and real-time quantitative polymerase chain reaction (RT-PCR) measurement in human cumulus cells.

RESULTS

Immunoreactive PR-A was mainly localized in the cytoplasm and PR-B was localized in the nuclei. There was no significant relationship between PR expression and follicular diameter, follicular fluid concentration of steroids, or LH. There was no significant relationship between expression of PRs and fertilization or cleavage rate. However, PR expression was lower in the good morphology group (blastomeres > or =7 cells with fragmentation > or =5% on day 3) when compared to the other groups (P<0.05).

CONCLUSIONS

These results suggest that follicular LH or steroids do not affect PR expression, and full reduction of total PR expression on cumulus cells at the time of oocyte collection is associated with good morphology in human oocytes.

The chromosomal analysis of human oocytes. An overview of established procedures

The cytogenetic survey of mature human oocytes has been and remains a subject of great interest because of the prevalence of aneuploidy of maternal origin in abnormal human conceptuses, and the lack of understanding about the non-disjunction processes in human meiosis. The first attempts to analyse the chromosomal content of human female gametes were made in the early 1970s, and led to limited data because of the paucity of materials and the inadequacy of the procedure used. The years to follow brought a resurgence of interest in this field, because of the development of human IVF techniques which made oocytes unfertilized in vitro available for cytogenetic analysis. Numerous studies have since been performed. However, the difficulties in obtaining good chromosome preparations and of performing accurate chromosome identification have reduced the viability of these studies, resulting in large variations in the reported incidences of chromosomal abnormalities. The further introduction of new procedures for oocyte fixation and the screening of large oocyte samples have allowed more reliable data to be obtained and to identify premature chromatid separation as a major mechanism in aneuploidy occurrence. The last decade has been privileged to witness the adaptation of molecular cytogenetic techniques to human oocytes, and thus various powerful procedures have been tried not only on female gametes, but also on polar bodies, involving sequential and multicolour fluorescent in situ hybridization (FISH) labelling, comparative genomic hybridization (CGH), spectral karyotyping and alternative methods such as primed in situ labelling (PRINS) and peptide nucleic acid (PNA) techniques. A large body of data has been obtained, but these studies also display a great variability in the frequency of abnormalities, which may be essentially attributable to the technical limitations of these in situ methods when applied to human oocytes. However, molecular cytogenetic approaches have also evidenced the co-existence of both whole chromosome non-disjunction and chromatid separation in maternal aneuploidy. In addition, the extension of these techniques to oocyte polar body materials has provided additional data on the mechanism of meiotic malsegregation. Improvements of some of these techniques have already been reported. The further development of new approaches for the in situ analysis of human meiosis will increase the impact of cytogenetic investigation of human oocytes in the understanding of aneuploidy processes in humans.

The incidence of aneuploidy in human oocytes assessed by conventional cytogenetic analysis

Human oocytes failing to fertilize during assisted reproduction are an important source of information for assessing incidence and causal mechanisms of maternal aneuploidy. This review describes the techniques of conventional oocyte chromosome analysis and evaluates the results of 59 studies comprising a total of>10,000 female gametes. The mean rate of aneuploidy (hypohaploidy + hyperhaploidy) amounts to approximately 20%, but this incidence is reduced as soon as possible artifacts introduced by the fixation technique are taken into consideration. It is therefore concluded that a realistic value for numerical abnormalities arising during first meiotic division lies between 12 and 15%. All chromosome groups are affected by aneuploidy but the actually observed frequencies exceed the expected frequencies in groups D, E, and G. Two aneuploidy-causing mechanisms have been identified in human oocytes: nondisjunction, resulting in the loss or gain of whole chromosomes, and predivision, resulting in the loss or gain of single chromatids. A brief analysis including only aneuploid complements with one extra or missing chromosome/chromatid shows a slight increase in predivision (52.9%) compared with nondisjunction (47.1%). Finally, suggestions for future studies are given since, for instance, the presentation of results and the use of cytogenetic nomenclature have not been uniform.

Relationship between follicular fluid hormone levels, embryo quality, and maternal age during in vitro fertilization after the short or long protocol with a gonadotropin releasing hormone agonist

Purpose:  To examine the relationship between embryo quality and follicular fluid hormonal level in short and long protocol gonadotrophin releasing hormone agonist treatment cycles. Methods:  A total of 90 patients had non-polycystic ovary syndrome (non-PCOS) and 10 had PCOS. A total of 100 subjects underwent in vitro fertilization (IVF). Thirty-six subjects underwent conventional IVF and 64 subjects underwent intracytoplasmic sperm injection (ICSI). The dominant follicles were initially retrieved and a hormonal assay was done. A total of 32 patients underwent a short protocol and 66 patients were treated with the long protocol. Estradiol (E₂), progesterone (P₄), total testosterone (TTE) and androstenedione (ASG) levels in follicular fluid (FF) were compared in the two treatment groups (short and long protocol), in regard to maternal age and oocyte/embryo quality. Results:  The retrieval FF volume was not significantly different between the PCOS and non-PCOS patients; however, P₄ was significantly lower with PCOS (P < 0.01). Analysis of four different hormone levels was not significantly different between the short and long protocol groups. No significant relationship was found between four hormone levels in regard to oocyte morphology and embryo quality. The levels of P₄ of younger women was significantly lower than that of older women; furthermore, a significantly higher TTE and ASG were found in the younger women. Progesterone was found to statistically significantly increase with FF volume. Conclusion:  Follicular fluid P₄ from the younger group was significantly lower, and TTE and ASG was significantly higher when compared to the older group. Analysis of four different hormone levels revealed no significant difference between the short and long protocol groups. No significant relationship was found between four hormone levels, oocyte morphology, and embryo quality. (Reprod Med Biol 2003; 2: 165-169).

Correlations between steroids concentration in follicular fluid, pronuclear morphology and embryo qualities in in vitro fertilization

Background:  Several parameters of early embryo development are known as predictors of implantation success. Recently, zygote or embryo morphological assessments are thought to be a major method of selection in embryo transfer. We expected that the concentrations of the steroids in follicular fluid (FF) were associated with oocyte maturation and embryo quality. In the present paper, we evaluated the relationship of several parameters. Methods:  We investigated 105 samples of FF from 22 subjects by in vitro fertilization (IVF). We evaluated the correlations between the FF concentrations of estradiol (E₂) and progesterone (P₄), the diameter of the ovarian follicles, fertilization, and zygote assessment based on pronuclear morphology and day 3 embryo qualities (i.e. number of blastomeres and fragmentation rate). Results:  There was a positive correlation between the E₂ concentrations in FF and serum (r = 0.273, P < 0.01), but there was no correlation between follicular diameter and the FF concentration of each steroid. The concentration of E₂ in FF containing fertilized oocytes was not significantly different from that in FF containing unfertilized oocytes. At the pronuclear stage, the concentration of either steroid in FF did not differ among the morphological groups. The concentration of P₄ in FF was significantly lower in the group in which pronuclei were detected at 20 h after insemination than in the group in which pronuclei were not detected. The concentration of E₂ in FF was significantly related to the number of blastomeres (r = 0.271, P < 0.05) and furthermore, was significantly higher in FF from which morphologically good embryos were obtained at day 3 (P < 0.05). Conclusions:  The FF concentrations of the steroids did not affect the pronuclear pattern, but P₄ production may play a role in reducing the potential of the oocyte to develop pronuclei and the concentration of E₂ may predict the cleavage capability of the oocyte. (Reprod Med Biol 2003; 2: 171-176).

Intracytoplasmic sperm injection could minimize the incidence of prematurely condensed human sperm chromosomes

OBJECTIVE

To compare the fertilization and prematurely condensed human sperm chromosomes (PCCs) rates between two intracytoplasmic sperm injection (ICSI) techniques.

DESIGN

A retrospective study.

SETTING

The data were obtained from the University of British Columbia in vitro fertilization (IVF) laboratory.

PATIENT(S)

ICSI cycles (n = 105) were performed for couples suffering from severe male-factor infertility and dysfunction of fertilization.

INTERVENTION(S)

Two types of ICSI techniques were used for ICSI procedures.

MAIN OUTCOME MEASURE(S)

Fertilization and pregnancy rates in group B using the improved ICSI technique were compared with those of group A using the standard ICSI technique. Unfertilized oocytes from the two groups were studied with cytogenetic methods.

RESULT(S)

Oocyte damage dropped from 14.8% in group A to 5.3% in group B. Normal fertilization for each group was 57.3% and 88.4%, respectively (P<.05). Pregnancy rate per egg retrieval was 15.6% in group A and 27.4% in group B (P<.05). PCCs occurred in 19.4% of unfertilized oocytes in group A and did not occur in group B.

CONCLUSION(S)

This study indicates that ICSI not only yields high fertilization rates, but also minimizes the incidence of PCCs. It may be directly related to two crucial steps (immobilization of sperm and aspiration of oocyte cytoplasm) used in ICSI procedures. This study also suggests that it is possible to overcome one cause of IVF failure resulting from the formation of PCCs by using the improved ICSI technique.

Serum and follicular fluid hormone levels during in vitro fertilization after short- or long-course treatment with a gonadotropin-releasing hormone agonist

OBJECTIVE

To examine the impact of flare (short) vs. down-regulation (long) GnRH agonist (GnRH-a) on serum and follicular fluid (FF) LH and androgen concentrations in women undergoing IVF treatment cycles.

DESIGN

Prospective observational study.

SETTING

IVF clinic.

PATIENT(S)

One hundred sixteen ovulatory subjects undergoing IVF.

INTERVENTION(S)

Fifty-eight ovulatory patients undergoing a down-regulation regimen matched with 58 undergoing the flare regimen as part of an IVF cycle.

MAIN OUTCOME MEASURE(S)

Serum concentrations of LH, FSH, Progesterone (P4), Androstenedione (A), T, and E(2) on the day of hCG administration were compared between the two groups. In addition, the FF P4, 17OHP4, A, T, and E(2) levels were compared in the two groups.

RESULT(S)

Serum LH was significantly higher with the flare regimen (15.2 +/- 1.14 IU/L, P<.05) when compared with results with the down-regulation protocol (9.5 +/- 0.77 IU/L). In addition, FF A was significantly higher in the flare protocol (57.3 +/- 13.3 ng/mL, P<.05) compared with in the down-regulation protocol (27 +/- 2.44 ng/mL). Serum and FF P4, 17OH P4, T, and E(2) were not statistically significantly different between the two groups.

CONCLUSION(S)

Serum LH and FF A are significantly higher in the flare regimen in comparison with the down-regulation regimen. Circulating LH appears to play a role in determining FF A concentration.

Oocyte morphology and early zygote cleavage does not appear to be related to intrafollicular concentrations of inhibin-A or -B

PURPOSE

The aim was to investigate the relationship of intrafollicular inhibin dimers A and B with human oocyte morphology and subsequent embryo potential.

METHODS

Sixty-eight oocytes were isolated from 31 women undertaking intracytoplasmic sperm injection (ICSI). Estradiol, progesterone, testosterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH), prolactin, sex hormone-binding globulin, inhibin-A and inhibin-B was assayed in corresponding follicular fluid.

RESULTS

The mean (+/- SD) concentration for inhibin-A was 9.7 +/- 9.8 ng/ml (range, 1.1-60.0 ng/ml) and for inhibin-B was 269.4 +/- 185.2 ng/ml (range, 33.1-811.0 ng/ml). In a correlation matrix there were no marked relationships (r < 0.556) between inhibin and steroid or gonadotropin concentrations. Similarly, when inhibin concentrations were divided according to whether the oocytes had mature or immature cumulous complexes, were viable or necrotic, were meiotically immature or mature, became fertilized or not, or had different embryo gradings after cleavage, no statistically significant difference could be seen between groupings.

CONCLUSIONS

Because the range of values was large and the data often skewed, neither inhibin dimer has discriminatory power to reflect the potential of the oocyte.

Environment of oocyte and embryo determines health of IVP offspring

In vitro embryo production (IVP) enhances the number of offspring from a single female and offers the possibility of accelerated genetic progress in animal husbandry. However, it also leads to a low but unacceptable percentage of anomalies in the offspring. The aim of this paper is to introduce the three speakers at this afternoon session who will speak about the demands of culture conditions and the endometrial environment to support normal embryonic development without effects on the embryonic genome. It will be argued that the in vitro conditions should mimic precisely the oviductal contributions to homeostatic mechanisms within the embryo. The further normal development can be guaranteed at synchrony in development of both endometrium and embryo. If that is not the case one can expect disturbances of gene expression, in particular of imprinted genes. However, it cannot be excluded that some processes might have started already in the cytoplasm of the oocyte. Since the oocyte was not planned to be a separate subject in this symposium, this introduction is also aimed to ask attention for the selection of cumulus-oocyte-complexes (COCs) and the conditions around oocyte maturation in vitro. The optimal quality of both the oocyte and maturation medium are prerequisites for an undisturbed cytoplasmic maturation. It has been argued that the exclusion of COCs from atretic follicles, the abjuration of the use of serum and high O2 tension in the gas phase might help to reduce the proportion anomalies in the offspring after synchronous transfers. In human IVF, in vivo matured oocytes are used with no great problems. But before IVP, including oocyte maturation in vitro (IVM) and a longer lasting embryo culture (IVC), will be introduced into the human assisted reproduction, it is important to think about the ins and outs of the potential causes for deviations.

Effect of follicle size and quality on the ability of follicular fluid to support cytoplasmic maturation of bovine oocytes

Recent studies have shown that the developmental capacity of in vitro-matured oocytes is affected by the origin of follicular fluid (FF) supplemented to the maturation medium. The aims of this study were (1) to determine if follicle size and quality would influence the capacity of FF to support bovine oocyte maturation and (2) to determine if fetal calf serum (FCS) and FF had an additive effect when added together to the maturation medium. Follicular fluid collected from 108 follicles was classified according to size ( < 6, 6-8, > 8 mm in diameter) and quality (healthy, early atretic, and atretic). Quality, first determined by mitosis/pycnosis ratios in granulosa cell smears, was subsequently confirmed by insulin-like growth factor binding protein (IGFBP) patterns and estradiol concentrations. While most small- or medium-sized follicles showed some atresia (88% and 67%, respectively), fewer of the large follicles were atretic (30%). In experiment 1 bovine oocytes (n = 2,152) were matured either in TCM199 alone, with 10% FCS, or with 10% FF from the following follicle types: small healthy (SH); small early atretic (SEA); small atretic (SA); medium healthy (MH); medium early atretic (MEA); medium atretic (MA); large healthy (LH); large early atretic (LEA); and large atretic (LA). Following IVM, oocytes were fertilized and subsequently cultured in synthetic oviduct fluid (SOF). Day 8 blastocyst yields were 23% in TCM199 alone; 37% in TCM199 plus FCS; and, in medium supplemented with FF, SH, 36%; MH, 32%; LH, 30%; SEA, 21%; MEA, 26%; LEA, 28%; SA, 32%; MA, 33%; and LA, 38%. All FF from healthy or atretic follicles resulted in significantly improved blastocyst yields compared to M199 alone (P < 0.05). However, FF from early atretic follicles irrespective of size did not yield a significant improvement. In experiment 2 we examined the effect of addition of FF-LH and serum together to the maturation medium. In terms of blastocyst yield, no additional benefit was observed when TCM199 was supplemented with 10% FCS + 10% FF (33%) compared to 10% FCS or FF alone (35% and 30%, respectively). The efficacy of FF as a supplement to the maturation medium to improve cytoplasmic maturation appears to vary with follicle quality but not size. However, in general, the addition of 10% FF or FCS to the maturation media resulted in a similar blastocyst yield with no additional improvement when media was supplemented with both FCS and FF.

Cytogenetic analysis of human oocytes parthenogenetically activated by puromycin

PURPOSE

Treatment of aged human oocytes by puromycin allows a high rate of parthenogenetic activation and development until the first cleavage division. This technique was used for the study of the chromosome complement of oocytes which remained unfertilized after in vitro fertilization. Three hundred four unfertilized oocytes were treated with 10 micrograms/ml puromycin for 6-8 hr and further cultured for 12-15 hr.

RESULTS

Activation occurred in 90.5% of the oocytes. Heterozygous diploids with two pronuclei predominated (61%), which is in contrast to the mouse, where the majority of oocytes activated by puromycin are uniform haploids (89%).

CONCLUSIONS

Therefore we conclude that puromycin treatment induces retention of the second polar body in human oocytes, unlike in mouse oocytes treated in the same way. Chromosome analysis performed on 182 oocytes suggested a nondisjunction (ND) rate for the second meiotic division of 12.7%. This is a low figure considering the fact that puromycin itself has been reported to induce nondisjunction. For the first meiotic division a ND rate of only 5.6% was found. This rate is lower than the one found in metaphase II arrested oocytes and we believe that this difference is due to the technical differences between the study of meiotic and that of mitotic chromosomes.

Parthenogenetic activation of human oocytes by puromycin

OBJECTIVE

Our objective was to obtain parthenogenetic activation of unfertilized human oocytes by puromycin and to try to use this procedure for cytogenetic purposes.

SETTING

The setting was our IVF laboratory.

METHODS

Eighty-two spare oocytes from 34 IVF patients were used. In the first series of experiments 39 unfertilized oocytes were cultured in medium containing 100, 50, or 10 micrograms/ml puromycin for 6 to 24 hr. After the appearance of pronuclei they were transferred to plain medium, further cultured, and cytogenetically analyzed. In the second series of experiments 43 oocytes were cultured for 5 to 10 hr in 10 micrograms/ml puromycin, transferred to plain medium, and fixed for cytogenetic analysis 2 hr after nuclear envelope breakdown.

RESULTS

Ninety-one percent of the oocytes in the first experiment showed the presence of one or more nuclei. From the pronucleate oocytes additionally cultured in puromycin-free medium, 46% developed further to the metaphase of the first mitotic division or the two-cell stage and 54% remained arrested at the pronuclear stage. In the second experiment 88% of the treated oocytes showed pronuclei or had cleaved, and after withdrawal from puromycin 96% of the pronucleate oocytes entered mitosis.

CONCLUSION

Puromycin induces haploid as well as diploid parthenogenesis in aged human oocytes. A 5- to 10-hr treatment of oocytes with 10 micrograms/ml puromycin yields the highest percentage of activation, and almost all parthenogenetically activated oocytes enter or develop beyond the first cleavage mitosis. Analysis of mitotic metaphase chromosomes from parthenogenetically activated human oocytes may be a promising new approach to preimplantation cytogenetics.

Hormonal stimulation for in vitro fertilization: a comparison of fertilization rates and cytogenetic findings in unfertilized oocytes

OBJECTIVE

The purpose of this study was to compare fertilization and aneuploidy rates after two stimulation protocols in an IVF program.

DESIGN

This was a retrospective study.

SETTING

The study took place in the IVF laboratory of an Infertility Department.

METHODS

In 349 treatment cycles, clomiphene citrate (CC) and human menopausal gonadotropin (hMG) were used in one group (N = 233) and hMG after treatment with a gonadotropin-releasing hormone agonist (GnRHa) in two other groups (long protocol): goserelin (N = 73) and buserelin (N = 43). Cytogenetic analysis was performed on all unfertilized oocytes in both groups.

RESULTS

Fertilization rates were significantly higher in the GnRHa/hMG group than in the CC/hMG group, but cleavage rates and embryo quality were not different. Of 736 oocytes prepared for cytogenetic analysis, 256 were karyotyped: 172 were found to be euploid and 84 aneuploid. More oocytes were aneuploid in the GnRHa/hMG group than in the CC/hMG group and this difference was statistically different after analysis of the data using a specially designed mathematical model.

CONCLUSION

If no selection against chromosomally abnormal oocytes takes place at the time of fertilization, more abnormal oocytes are harvested with GnRHa/hMG protocols than with CC/hMG. If, on the other hand, there is a selection against oocytes with some chromosomal imbalance, there is no intrinsic effect of GnRH agonists on the chromosomal complement of the oocyte, and the real aneuploidy frequency in all oocytes, fertilized and unfertilized, is the same in the GnRHa/hMG and in the CC/hMG group.

Is there any correlation between follicular fluid hormone concentrations, fertilizability, and cytogenetic analysis of human oocytes recovered for in vitro fertilization?

Constituents of FF have been suspected to influence fertilizability and cytogenetic constitution of human oocytes. We therefore analyzed the FF concentrations of E2, P, T, and PRL for 114 oocytes recovered for IVF. Forty-six of these oocytes were fertilized and transferred to the maternal uterus. Among the unfertilized gametes, 27 were not analyzable, 30 were normal haploid, and 11 were classified as abnormal. There was no significant difference between fertilized and unfertilized oocytes for FF concentrations of E2, P, T, and PRL and for the E2:P ratios. Similarly, we detected no significant difference between normal and abnormal oocytes for these parameters.