Prognosis of oocytes showing aggregation of smooth endoplasmic reticulum

The Relationship Between Smooth Endoplasmic Reticulum Clusters in Metaphase II Oocytes and Embryological and Birth Outcomes in Infertile Couples

Background

To assess the relationship between oocytes with smooth endoplasmic reticulum cluster (SERc) and embryological and birth outcomes in infertile couples.

Methods

This was a descriptive study that included 231 infertile patients undergoing in vitro fertilization (IVF) with a total of 2447 mature oocytes (MII), of which 279 oocytes with SERc(+) from 100 patients, the remaining 2168 oocytes with SERc(-). Oocytes were evaluated for the presence or absence of the SERc simultaneously with intracytoplasmic sperm injection at 200x magnification using inverted microscopy - Observe D1.

Results

The mean age of patients was 32.05 ± 5.56 years. One hundred patients had at least one SERc(+) oocyte (with 279 SERc(+) and 956 SERc(-) oocytes). One hundred and thirty-one patients had 1212 SERc(-) oocytes. Fertilization outcomes and the rates of good-quality embryos on day 2 and day 5 did not differ between the SERc(+) and the SERc(-) groups. In the first frozen embryo transfer cycles, the clinical pregnancy rate in the group of patients with SERc(+) was not different with the SERc(-) group (61.1% vs 48.78%, p = 0.074, respectively). The live birth rate in the SERc(+) group was statistically significantly higher than the SERc(-) group (57.7% vs 43.9%, p = 0.045, respectively).

Conclusion

The fertilization rate, the quality of embryos on days 2 and 5 from oocytes with SERc(+) are similar to those with SERc(-). The live birth rate in the patients with SERc(+) group is statistically significantly higher than the SERc(-) group. There is no difference in clinical pregnancy rate between patients with and without SERc. Therefore, the exclusion of oocytes with SERc should not be recommended.

Smooth endoplasmic reticulum aggregates in oocytes associated with increased risk of neonatal birth defects: A meta-analysis

INTRODUCTION

Previous studies have indicated the association between smooth endoplasmic reticulum aggregates (SERa+) and poorer medically assisted reproduction outcomes. However, the link between SERa+ and neonatal outcomes remains controversial and open for debate. A comprehensive meta-analysis on the relation between SERa+ and the risk of birth defects is needed.

MATERIAL AND METHODS

The literature search was conducted using the following databases: PubMed, Embase, Cochrane Libraries, Web of Science, and Chinese databases including China National Knowledge Infrastructure (CNKI) and Wan Fang from inception until July 2023. Risk ratio (RR) and 95% confidence interval (CI) were calculated by a fixed-effected model, while heterogeneity was assessed by forest plots and I2 statistic. Funnel plot was produced to assess publication bias. This meta-analysis has been registered on PROSPERO (CRD42022313387).

RESULTS

The search resulted in 122 studies, 14 of which met the inclusion criteria. The analysis of birth defects revealed a higher risk (RR = 2.17, 95%CI 1.24 to 3.81, p = 0.007) in children derived from SERa+ cycle compared to SERa- cycles (711 vs. 4633). Meanwhile, in a subgroup analysis, the risk of birth defects was significantly increased in the SERa+ oocytes group as compared with the sibling SERa- oocytes group (RR = 3.53, 95%CI 1.21 to 10.24, p = 0.02).

CONCLUSIONS

To conclude, our analysis indicated that SERa+ cycles/oocytes may have a potential risk of increased additional major birth defects comparing with SERa- cycles/oocytes. This conclusion may provide evidence-based support for clinicians in IVF clinical guidance and embryologists in prudent embryo selection strategy.

The ultrastructural nature of human oocytes' cytoplasmic abnormalities and the role of cytoskeleton dysfunction

OBJECTIVE

To investigate the structural bases of human oocytes' cytoplasmic abnormalities and the causative mechanism of their emergence. Knowledge of an abnormal oocyte's intracellular organization is vital to establishing reliable criteria for clinical evaluation of oocyte morphology.

DESIGN

Laboratory-based study on experimental material provided by a private assisted reproduction clinic.

SETTING

University laboratory and imaging center.

PATIENTS

A total of 105 women undergoing hormonal stimulation for in vitro fertilization (IVF) donated their spare oocytes for this study.

INTERVENTIONS

Transmission electron microscopy (TEM) was used to analyze the fine morphology of 22 dysmorphic IVF oocytes exhibiting different types of cytoplasmic irregularities, namely, refractile bodies; centrally located cytoplasmic granularity (CLCG); smooth endoplasmic reticulum (SER) disc; and vacuoles. A total of 133 immature oocytes were exposed to cytoskeleton-targeting compounds or matured in control conditions, and their morphology was examined using fluorescent and electron microscopy.

MAIN OUTCOME MEASURES

The ultrastructural morphology of dysmorphic oocytes was analyzed. Drug-treated oocytes had their maturation efficiency, chromosome-microtubule configurations, and fine intracellular morphology examined.

RESULTS

TEM revealed ultrastructural characteristics of common oocyte aberrations and indicated that excessive organelle clustering was the underlying cause of 2 of the studied morphotypes. Inhibition experiments showed that disruption of actin, not microtubules, allows for inordinate aggregation of subcellular structures, resembling the ultrastructural pattern seen in morphologically abnormal oocytes retrieved in IVF cycles. These results imply that actin serves as a regulator of organelle distribution during human oocyte maturation.

CONCLUSION

The ultrastructural analogy between dysmorphic oocytes and oocytes, in which actin network integrity was perturbed, suggests that dysfunction of the actin cytoskeleton might be implicated in generating common cytoplasmic aberrations. Knowledge of human oocytes' inner workings and the origin of morphological abnormalities is a step forward to a more objective oocyte quality assessment in IVF practice.

The impact of oocyte central granularity on ICSI practice: developmental competence of dysmorphic and morphologically normal companion oocytes

PURPOSE

To assess the effects of oocyte central granularity and its underlying endocrine environment on developmental competence of dysmorphic and morphologically normal oocytes.

METHODS

Retrospective cohort study including 1,082 patients undergoing autologous ICSI cycles. Of these, 211 patients provided 602 oocytes with central granularity (CG) and 427 morphologically normal cycle companion oocytes (NCG). The remaining 871 patients provided only morphologically normal oocytes in cycles not yielding dysmorphic oocytes (N). Patient profile associated with CG was characterized, and fertilization rates, early morphokinetics and live birth rates were compared between N, CG and NCG groups. Patient characteristics associated with implantation and delivery performance of CG-derived embryos were assessed.

RESULTS

CG was associated with higher maternal age, basal FSH concentrations and total FSH dose, but with lower circulating AMH (p ≤ 0.035). Fertilization rates were reduced and early morphokinetic parameters were delayed in CG (p < 0.025) and NCG (p < 0.05) groups as compared to the N group. Embryos derived from CG oocytes achieved a markedly lower live birth rate (14.9%) as compared to those derived from NCG (36.8%; p = 0.03) and N oocytes (29.8%; p = 0.002). The negative relationship between CG and live birth was confirmed by a multivariate analysis controlling for potential confounders (OR:2.59, IC:1.27-5.31; P = 0.009). Implantation and delivery rates following transfers of CG-derived embryos were inversely associated with maternal age.

CONCLUSION

CG oocytes, but not their morphologically normal cycle companions, have severely compromised developmental competence. Maternal age should be a key parameter in deciding whether or not to utilize CG oocytes in ICSI cycles.

Aging and oocyte competence: A molecular cell perspective

Follicular microenvironment is paramount in the acquisition of oocyte competence, which is dependent on two interconnected and interdependent processes: nuclear and cytoplasmic maturation. Extensive research conducted in human and model systems has provided evidence that those processes are disturbed with female aging. In fact, advanced maternal age (AMA) is associated with a lower chance of pregnancy and live birth, explained by the age-related decline in oocyte quality/competence. This decline has largely been attributed to mitochondria, essential for oocyte maturation, fertilization, and embryo development; with mitochondrial dysfunction leading to oxidative stress, responsible for nuclear and mitochondrial damage, suboptimal intracellular energy levels, calcium disturbance, and meiotic spindle alterations, that may result in oocyte aneuploidy. Nuclear-related mechanisms that justify increased oocyte aneuploidy include deoxyribonucleic acid (DNA) damage, loss of chromosomal cohesion, spindle assembly checkpoint dysfunction, meiotic recombination errors, and telomere attrition. On the other hand, age-dependent cytoplasmic maturation failure is related to mitochondrial dysfunction, altered mitochondrial biogenesis, altered mitochondrial morphology, distribution, activity, and dynamics, dysmorphic smooth endoplasmic reticulum and calcium disturbance, and alterations in the cytoskeleton. Furthermore, reproductive somatic cells also experience the effects of aging, including mitochondrial dysfunction and DNA damage, compromising the crosstalk between granulosa/cumulus cells and oocytes, also affected by a loss of gap junctions. Old oocytes seem therefore to mature in an altered microenvironment, with changes in metabolites, ribonucleic acid (RNA), proteins, and lipids. Overall, understanding the mechanisms implicated in the loss of oocyte quality will allow the establishment of emerging biomarkers and potential therapeutic anti-aging strategies. This article is categorized under: Reproductive System Diseases > Molecular and Cellular Physiology.

Endoplasmic reticulum in oocytes: spatiotemporal distribution and function

ENDOPLASMIC RETICULUM IN OOCYTES

The storage and release of calcium ions (Ca2 +) in oocyte maturation and fertilization are particularly noteworthy features of the endoplasmic reticulum (ER). The ER is the largest organelle in the cell composed of rough ER, smooth ER, and nuclear envelope, and is the main site of protein synthesis, transport and folding, and lipid and steroid synthesis. An appropriate calcium signaling response can initiate oocyte development and embryogenesis, and the ER is the central link that initiates calcium signaling. The transition from immature oocytes to zygotes also requires many coordinated organelle reorganizations and changes. Therefore, the purpose of this review is to generalize information on the function, structure, interaction with other organelles, and spatiotemporal localization of the ER in mammalian oocytes. Mechanisms related to maintaining ER homeostasis have been extensively studied in recent years. Resolving ER stress through the unfolded protein response (UPR) is one of them. We combined the clinical problems caused by the ER in in vitro maturation (IVM), and the mechanisms of ER have been identified by single-cell RNA-seq. This article systematically reviews the functions of ER and provides a reference for assisted reproductive technology (ART) research.

Live birth rate per transfer is not impacted by the proportion of smooth endoplasmatic reticulum aggregates oocytes

BACKGROUND

Despite the data published to date, prognostic factors and the clinical impact of ICSI cycles with smooth endoplasmatic reticulum aggregates (SERa) positive oocytes remain unclear.

OBJECTIVE

Are the clinical outcomes of an ICSI cycle impacted by the proportion of oocytes with SERa?

MATERIALS AND METHODS

Retrospective study (2016-2019), including data from 2468 ovum pick-ups, performed in a tertiary university hospital. Cases are categorised based on the rate of SERa positive oocytes compared to the total number of MII oocytes: 0% (n=2097), <30% (n=262) and ≥30% (n=109).

MAIN OUTCOME MEASURES

Patient characteristics, cycle characteristics and clinical outcomes are compared between the groups.

RESULTS

Compared to SERa negative cycles, women with ≥30% SERa positive oocytes are older (36.2y vs. 34.5y, p<0.001), have lower anti-mullerian hormone levels (AMH) (1.6ng/ml vs. 2.3ng/ml, p<0.001), have received more gonadotropins (3227U vs. 2858IU, p=0.003), have a lower number of good quality day 5 blastocysts (1.2 vs. 2.3, p<0.001) and face more blastocyst transfer cancellation (47.7 vs. 23.7%, p<0.001). Women with <30% SERa positive oocytes are younger (33.8y, p=0.04), have higher AMH levels (2.6ng/ml, p<0.001), have more oocytes retrieved (15.1, p<0.001), have a higher number of good quality day 5 blastocysts (3.2, p<0.001) and have less transfer cancellations (14.9%, p<0.001) compared to SERa negative cycles A multivariate analysis shows no significant difference in cycle outcomes between the categories.

WHAT IS NEW?

Treatment cycles with ≥30% SERa positive oocytes are less likely to result in an embryo transfer when only non-SER oocytes are used. However, live birth rate per transfer is not affected by the proportion of SERa positive oocytes.

Does smooth endoplasmic reticulum aggregation in oocytes impact the chromosome aneuploidy of the subsequent embryos? A propensity score matching study

BACKGROUND

The appearance of smooth endoplasmic reticulum aggregation (SERa) is one of the most common dysmorphic phenotypes of oocytes, however, the impact of SERa occurrence on in vitro fertilization (IVF) outcomes is controversial. This study aimed to investigate the impact of SERa in oocytes on the aneuploidy of the subsequent embryos in IVF.

METHODS

In this retrospective cohort study, a total of 114 intracytoplasmic sperm injection (ICSI) cycles with the appearance of SERa undergoing preimplantation genetic testing for aneuploidy (PGT-A) were enrolled, and among them there were 323 SERa(+) oocytes and 1253 sibling unaffected oocytes. The 907 PGT-A cycles without SERa during the same period were enrolled as controls. A propensity score matching of 1:1 ratio between these two groups resulted in 113 matched cycles. The outcome parameters between the SERa(+) cycles/oocytes and the controls were compared. IVF laboratory outcomes, PGT-A outcomes, and clinical and neonatal outcomes were the main outcomes.

RESULTS

Increased abnormal fertilization rate and reduced blastocyst formation rate can be observed in both SERa(+) cycles and oocytes, some other parameters on developmental potential, such as available embryo rate at Day 3 and available blastocyst rate, were also impaired in the case of SERa occurrences. Among the 910 blastocysts for PGT-A, the percentage of euploid embryos was similar between the matched cohorts, while an unpredicted increase of the proportions of euploid in the SERa(+) oocytes, compared to the SERa(-) oocytes. Moreover, there was no significance in terms of clinical and neonatal outcomes, such as implantation rate, biochemical pregnancy rate, clinical pregnancy rate, miscarriage rate, and live birth rate, regardless of the presence of SERa in cycles and oocytes.

CONCLUSIONS

The appearance of SERa within mature oocytes has no significant impact on the aneuploidy of subsequent blastocysts. It is recommended to utilize these oocytes, especially for those with few oocytes or advanced maternal age, which is likely to increase the cumulative pregnancy rate. This study may offer evidence to assist embryologists to make clinical decisions concerning SERa(+) oocytes more consciously and rationally.

Smooth endoplasmic reticulum cluster presence does not affect embryo ploidy

PURPOSE

We examined the impacts of the smooth endoplasmic reticulum cluster (sERC) presence on embryonic development and blastocyst ploidy.

METHODS

Patients who underwent oocyte retrieval from January 2019 to November 2021 were included in the study. We classified the oocytes into three groups: normal oocytes in the sERC ( -) cycle, normal oocytes in the sERC ( +) cycle, and sERC ( +) oocytes. Next, the levels of serum estradiol, progesterone, anti-Mullerian hormone, follicle-stimulating hormone, and human menopausal gonadotropin were compared between the groups. Moreover, fertilization, degeneration, and abnormal fertilization rates were compared between groups. To investigate developmental outcomes, the blastocyst and good-quality blastocyst rates after intracytoplasmic sperm injection were compared. The quality of the transferred blastocysts was evaluated at follow-up. Additionally, embryos were submitted for next-generation sequencing analysis to examine the effect of sERC presence on ploidy.

RESULTS

The sERC ( +) group had significantly higher serum estradiol, serum progesterone, and serum anti-Mullerian hormone concentrations compared to those in the sERC ( -) group (P < 0.01). The abnormal fertilization rate was higher in the sERC ( +) cycle-sERC ( +) oocyte group (16.1%; 37/230) than in the sERC ( +) cycle-normal oocyte (6.2%; 63/971) and sERC ( -) cycle-normal oocyte groups (7.1%; 174/2467) (P < 0.01). After embryo transfer, nine women gave birth, and no confirmed congenital anomalies were observed. There was no significant difference in ploidy between the sERC ( +) and sERC ( -) groups.

CONCLUSION

The occurrence rates of embryos with euploidy were similar between the sERC ( +) and sERC ( -) groups.

Assisted Reproductive Technology without Embryo Discarding or Freezing in Women ≥40 Years: A 5-Year Retrospective Study at a Single Center in Italy

The protocols commonly used in assisted reproductive technology (ART) consist of long-term embryo culture up to the blastocyst stage after the insemination of all mature oocytes, the freezing of all the embryos produced, and their subsequent transfer one by one. These practices, along with preimplantation genetic testing, although developed to improve the live birth rate (LBR) and reduce the risk of multiple pregnancies, are drawing attention to the possible increase in obstetric and perinatal risks, and adverse epigenetic consequences in offspring. Furthermore, ethical-legal concerns are growing regarding the increase in cryopreservation and storage of frozen embryos. In an attempt to reduce the risk associated with prolonged embryo culture and avoid embryo storage, we have chosen to inseminate a limited number of oocytes not exceeding the number of embryos to be transferred, after two days or less of culture. We retrospectively analyzed 245 ICSI cycles performed in 184 infertile couples with a female partner aged ≥40 from January 2016 to July 2021. The results showed a fertilization rate of 95.7%, a miscarriage rate of 48.9%, and a LBR of 10% with twin pregnancies of 16.7%. The cumulative LBR in our group of couples was 13%. No embryos were frozen. In conclusion, these results suggest that oocyte selection and embryo transfer at the cleaving stage constitute a practice that has a LBR comparable to that of the more commonly used protocols in older women who have reduced ovarian reserve.

The impact of oocytes containing smooth endoplasmic reticulum aggregates on assisted reproductive outcomes: a cohort study

Background

The impact of smooth endoplasmic reticulum aggregates (SERa) on assisted reproductive technology (ART) outcomes was still controversial. Our objective is to investigate the impact of the presence of SERa on intracytoplasmic sperm injection (ICSI) outcomes.

Methods

This was a retrospective cohort study. A total of 1,090 fresh ICSI cycles from 944 patients between January 2016 and June 2020 were included. Outcomes from clinical, embryological and neonatal aspects were compared between SERa + and SERa- cycles as well as between SERa + and SERa- oocytes.

Results

The total gonadotropin (Gn) dose, number of oocytes retrieved, serum estradiol concentration and number of the available embryo were significantly higher in SERa + cycles than in SERa- cycles (P < 0.05). Comparable two pronuclei (2PN) fertilization rate and poly-pronucleus zygote rate were shown in SERa + and SERa- cycles (P > 0.05), but which were higher in SERa + oocytes than in SERa- oocytes (P < 0.05). No statistical difference in blastocyst formation rate was found in SERa + and SERa- cycles as well as in SERa + and SERa- oocytes (P > 0.05). Good-quality embryo rate was statistically higher in SERa- cycles than in SERa + cycles (P < 0.05), but the difference was comparable between SERa + and SERa- oocytes (P > 0.05). No statistical difference in clinical pregnancy rate, spontaneous abortion rate, live birth rate and premature delivery rate were found in SERa + and SERa- cycles as well as in SERa + and SERa- oocytes (P > 0.05). The implantation rate was comparable in SERa + and SERa- cycles (P > 0.05), but it is higher in the group of only SERa- embryo transfer when compared with the group of mixed SERa + and SERa- embryo transfer (P < 0.05). 159 newborns in SERa + cycles and 140 newborns in SERa- cycles were followed up. Comparable newborn malformation rate was observed between SERa + and SERa- cycles and oocytes (P > 0.05). Logistic regression analysis revealed number of oocytes and total dose of Gn were risk factors for SERa occurrence (aOR = 1.05 and 1.55, P < 0.001).

Conclusion

Oocyte's SERa is correlated with a number of oocytes retrieved and higher Gn dose, but it does not affect pregnancy outcomes and increase newborn malformation rate.

Metaphase II (MII) human oocytes with smooth endoplasmic reticulum clusters do not affect blastocyst euploid rate

OBJECTIVE

To investigate whether the rate of euploidy and pregnancy outcomes are affected by smooth endoplasmic reticulum clusters (SERc) and other metaphase II human oocyte dysmorphisms.

MATERIALS AND METHODS

Retrospective analysis of the morphologies of metaphase II (MII) human oocytes, which had developed into 590 biopsied blastocysts derived from 109 patients that received preimplantation genetic testing for aneuploidies (PGT-A) cycles between March 2013 and December 2017. The euploid rate of blastocysts that originated from morphologically abnormal or normal oocytes were analyzed. The chromosome status of the blastocysts was determined and analyzed by array comparative genomic hybridization (aCGH) or next generation sequencing (NGS) following trophectoderm biopsy.

RESULTS

According to the odds ratios obtained for each oocyte morphotype, no statistically significant relationship was found between oocyte dysmorphisms and euploid rate. Specifically, although SERc-positive oocytes had a higher rate of arrest at two pronuclei, or 2 PN (26.7% vs. 19.4%, p > 0.05), the blastocyst formation rate was not affected as compared with SERc-negative oocytes (40.0% vs. 38.6%, p > 0.05). Among nine euploid embryos derived from oocytes with SERc, three single euploid embryo transfers were performed, of which one resulted in blighted ovum, and two resulted in the births of two healthy, singleton term babies.

CONCLUSION

The results presented here suggest that oocyte dysmorphisms do not affect the euploidy rate of the blastocyst. The occurrence of SERc in the oocyte does not seem to impair the developing blastocyst nor does it interfere with good embryo formation rate and euploid rate. Thus, the embryos derived from SERc-positive oocytes could still be considered for embryo transfer if there are no other embryos available.

Oocyte quality and embryo selection strategies: a review for the embryologists, by the embryologists

With the advance of assisted reproduction techniques, and the trend towards blastocyst culture and single embryo transfer, gamete and embryo assessment have gained greater importance in ART treatment. Embryo quality depends mainly on gamete quality and culture conditions. Oocyte maturity identification is necessary in order to plan fertilization timing. Mature oocytes at the metaphase II stage show a higher fertilization rate compared to immature oocytes. Morphology assessment is a critical yet challenging task that may serve as a good prognostic tool for future development and implantation potential if done effectively. Various grading systems have been suggested to assess embryos at pronuclear, cleavage, and blastocyst stages. By identifying the embryo with the highest implantation potential, it is possible to reduce the number of embryos transferred without compromising the chances of a successful pregnancy. Apart from the conventional morphology assessment, there are several invasive or non-invasive methods for embryo selection such as preimplantation genetic testing, morphokinetics, proteomics, metabolomics, oxygen consumption, and measurement of oxidative stress in culture medium. Morphokinetics is a method based on time-lapse technology and continuous monitoring of embryos. In this review, we aim to describe and compare the most effective and widely used methods for gamete and embryo assessment as well as embryo selection.

Does morphological assessment predict oocyte developmental competence? A systematic review and proposed score

PURPOSE

Does existing scientific literature suggest an impact of oocyte dysmorphisms on biological or clinical outcomes of assisted reproduction treatments?

METHODS

Studies of interest were selected from an initial cohort of 6651 potentially relevant records retrieved. PubMed was systematically searched for peer-reviewed original papers and reviews identified by keywords and medical subject heading (MeSH) terms. The most relevant publications were critically evaluated to identify criteria for oocyte morphological evaluation and IVF outcomes. For each morphological abnormality, we generated an oocyte literature score (OLS) through the following procedure: (a) papers showing a negative, absence of, or positive correlation between a given abnormality and IVF outcome were scored 1, 0, and - 1, respectively; (b) the sum of these scores was expressed as a fraction of all analyzed papers; (c) the obtained fraction was multiplied by 10 and converted into decimal number.

RESULT

We identified eleven different dysmorphisms, of which six were extracytoplasmic (COC, zona pellucida, perivitelline space, polar body 1, shape, giant size) and five intracytoplasmic (vacuoles, refractile bodies, SER clusters, granularity, color). Among the extracytoplasmic dysmorphisms, abnormal morphology of the COC generated an OLS of 8.33, indicating a large prevalence (5/6) of studies associated with a negative outcome. Three intracytoplasmic dysmorphisms (vacuoles, SER clusters, and granularity) produced OLS of 7.14, 7.78, and 6.25, respectively, suggestive of a majority of studies reporting a negative outcome.

CONCLUSION

COC morphology, vacuoles, SER clusters, and granularity produced OLS suggestive of a prevalence of studies reporting a negative outcome.

Oocytes With Smooth Endoplasmic Reticulum Aggregates May Not Impact Blastocyst Euploidy Rate

OBJECTIVE

To investigate whether the euploidy rate of blastocysts derived from smooth endoplasmic reticulum aggregates (SERa) positive cycles and oocytes are impacted.

DESIGN

Retrospective cohort study.

METHODS

A total of 601 preimplantation genetic testing (PGT) cycles with at least one oocyte retrieved in our center between April 2017 and May 2021 were initially included in the study. Women>35 years and PGT cycles with chromosomal structural rearrangements (PGT-SR) were excluded. Embryological and blastocyst ploidy outcomes were compared among SERa+ oocyte, sibling SERa- oocytes and oocytes in SERa- cycles.

RESULTS

No significant difference was observed among the SERa+ oocyte group, sibling SERa- oocyte group, and SERa- cycle group in the normal fertilization rate (82.1% vs. 77.8% vs. 83.1%, respectively, P=0.061), blastocyst formation rate (71.0% vs. 72.5% vs. 68.4%, respectively, P=0.393), good quality blastocyst formation rate (46.4% vs. 48.3% vs. 42.6%, respectively, P=0.198). No significant difference was observed in the euploidy rate (50.0% vs. 62.5% vs. 63.3%, respectively, P=0.324), mosaic rate (12.5% vs. 9.7% vs. 13.4%, respectively, P=0.506), and aneuploidy rate (37.5% vs. 27.8% vs. 23.2%, respectively, P=0.137) among the three groups.

CONCLUSION

Our results suggest that the euploidy rate of blastocysts derived from SERa+ cycles and oocytes may not be impacted.

Smooth Endoplasmic Reticulum Clusters in Oocytes From Patients Who Received Intracytoplasmic Sperm Injections Negatively Affect Blastocyst Quality and Speed of Blastocyst Development

Findings regarding the relationship between smooth endoplasmic reticulum clusters (SERCs) in oocytes and blastocyst development have been conflicting. In this study, the effects of SERCs on blastocyst quality and the speed of blastocyst development were evaluated. Patients who received intracytoplasmic sperm injections (ICSI) at our reproductive center from 2016 to 2020 were retrospectively analyzed. SERC (+) oocytes (n = 217) and SERC (–) oocytes (n = 822), as well as SERC (+) cycles (n = 146) and SERC (–) cycles (n = 1,951) were compared. There was no significant difference in embryological, clinical, and neonatal outcomes between the SERC (+) and SERC (–) cycles. The fertilization rate (73.9%), good quality blastocyst rate (26.7%) and the speed of blastocyst development (44.4%) were significantly lower (P < 0.05) in SERC (+) oocytes than in unaffected counterparts (86.2%, 44.1% and 63.4%, respectively). Furthermore, the proportion of blastocysts with trophectoderm (TE) grade C was significantly higher in the SERC (+) oocyte group than in the SERC (–) oocyte group (73.3 vs. 55.9%, P < 0.05). After adjusting for age, years of infertility, endometriosis, stimulation protocols (GnRHa), and male infertility, multiple logistic regression analysis revealed that the presence of SERCs in the oocytes significantly affected the speed of blastocyst development (odds ratio, 2.812; 95% CI, 1.257–6.292; P = 0.012). These findings suggest that the presence of SERCs in oocytes may negatively affect blastocyst quality and the speed of blastocyst development.

Human Oocyte Morphology and Outcomes of Infertility Treatment: a Systematic Review

Oocyte morphology assessment is easy to implement in any laboratory with possible quality grading prior to fertilization. At present, comprehensive oocyte morphology scoring is not performed as a routine procedure. However, it may augment chances for successful treatment outcomes if a correlation with certain dysmorphisms can be proven. In order to determine a correlation between oocyte morphology and treatment outcome, we performed a systematic search in PubMed and Cochrane Controlled Trials Register following PRISMA guidelines. A total of 52 articles out of 6,755 search results met the inclusion criteria. Dark colour of the cytoplasm (observed with an incidence rate of 7%), homogeneous granularity of the cytoplasm (19%) and ovoid shape of oocytes (7%) appeared to have no influence on treatment outcome. Abnormalities such as refractile bodies (10%), fragmented first polar body (37%), dark zona pellucida (9%), enlarged perivitelline space (18%) and debris in it (21%) are likely to affect the treatment outcome to some extent. Finally, cytoplasmic vacuoles (4%), centrally located cytoplasmic granularity (12%) and clusters of smooth endoplasmic reticulum (4%) negatively impact infertility treatment outcomes. Nonetheless, morphological assessment is informative rather than predictive. Adding oocyte morphology to the artificial intelligence (AI)-driven selection process may improve the precision of the algorithms. Oocyte morphology assessment can be especially useful in oocyte donation cycles, during oocyte freezing for fertility preservation and finally, objective oocyte scoring can be important in cases of very poor treatment outcome as a tool for explanation of results to the patient.

Occurrence of smooth endoplasmic reticulum aggregates in metaphase II oocytes: relationship with stimulation protocols and outcome of ICSI and IVF cycles

STUDY QUESTION

Is there any association between the appearance of smooth endoplasmic reticulum aggregates (SERa) in oocytes and ovarian stimulation, embryological, clinical and neonatal outcomes of ICSI and IVF cycles?

SUMMARY ANSWER

A suboptimal prolonged ovarian stimulation is detrimental to oocytes by inducing the occurrence of SERa, which reduces the reproductive potential of oocytes.

WHAT IS KNOWN ALREADY

Controlled ovarian stimulation recruits oocytes of different qualities. Based on current evidence, it was agreed that non-homogeneous cytoplasm may represent the normal variability among oocytes rather than a dysmorphism with developmental significance. The only exception is the appearance of SERa within the ooplasm. Owing to the lack of univocal evidence in this literature about the safety of injecting oocytes with SERa and the mechanism responsible for the occurrence of SERa, this topic is still a matter of debate.

STUDY DESIGN, SIZE, DURATION

A retrospective, longitudinal cohort study performed at a tertiary level public infertility center. We included 1662 cycles (180 SERa+ and 1482 SERa-) from 1129 women (age: 20-44 years) who underwent IVF/ICSI treatments in 2012-2019. The SERa+ cycles had at least one SERa+ oocyte in the oocyte cohort. The SERa- cycles had morphologically unaffected oocytes.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We collected stimulation data and embryological, clinical, neonatal outcomes of SERa- and SERa+ cycles and oocytes.

MAIN RESULTS AND THE ROLE OF CHANCE

Overall, 347 out of 12 436 metaphase II oocytes (2.8%) were affected by SER. We performed only 12 transfers involving at least one SERa+ embryo. Stimulation length (P = 0.002), serum progesterone (P = 0.004) and follicle size (P = 0.046) at trigger, number of retrieved (P = 0.004) and metaphase II (P = 0.0001) oocytes were significantly higher in SERa+ than SERa- cycles. Fertilization rate was significantly (P < 0.0001) reduced in SERa+ cycles and oocytes compared to SERa- counterparts. Embryos of SERa+ cycles had a lower blastocyst formation rate compared to embryos of SERa- cycles (P = 0.059). Statistical analysis according to a generalized estimating equation model performed at patient level demonstrated that the duration of ovarian stimulation was predictive of SERa+ oocytes appearance. The clinical success of SERa+ cycles was lower than SERa- cycles, although no differences in neonatal birthweights or malformations were recorded in sibling unaffected oocytes of SERa+ cycles.

LIMITATIONS, REASONS FOR CAUTION

Given that SERa+ oocytes were discarded in our center for years and transfers of embryos originating from affected oocytes were generally avoided, clinical outcomes of SERa+ cycles are largely attributable to the transfer of embryos derived from unaffected oocytes of SERa+ cycles and we did not have data about newborns from affected oocytes, since none of the transfers involving SERa+ embryos resulted in a progressive clinical pregnancy.

WIDER IMPLICATIONS OF THE FINDINGS

For the first time, we speculate that the late-follicular phase elevated serum progesterone caused by a suboptimal prolonged ovarian stimulation may be detrimental to the oocytes by inducing the occurrence of SERa, resulting in negative effects on their reproductive potential. This raises the question of whether some stimulation regimens could be worse than others and a change in stimulation protocol would reduce the possibility of producing oocytes with suboptimal maturation. In particular, our data highlight the importance of correct timing of the trigger in order to maximize oocyte collection, not only in terms of numerosity but also their reproductive potential.

STUDY FUNDING/COMPETING INTEREST(S)

None.

TRIAL REGISTRATION NUMBER

N/A.

Meta-analysis of the effects of smooth endoplasmic reticulum aggregation on birth outcome

BACKGROUND

Smooth endoplasmic reticulum aggregation (SERa, SER+) has been reported to increase the risk of birth malformations and other abnormal outcomes, miscarriage, and perinatal complications. Other studies, however, suggest that SER+ embryos may develop into healthy infants. One report indicates that 25% of in vitro fertilization (IVF) centers discard SER+ oocytes. Thus, we investigated the effect of SER+ on birth outcomes in IVF and intracytoplasmic sperm injection.

METHODS

We performed a literature search using PubMed, ScienceDirect, Cochrane, Embase, Ovid, and Scopus. We found a total of 1500 relevant studies between 1978 and 2020 and conducted a meta-analysis to study the effects of SER+ on live births, birth weight, and the number of metaphase II (MII) oocytes retrieved per cycle.

RESULTS

Eleven eligible studies were included. If the SER+ zygote was evaluated again at the embryo transfer (ET) stage, SER+ did not affect birth or infant body weight. Stimulated ovaries producing too many oocytes per cycle were positively correlated with SER+ (OR = 1.28, 95% CI = 0.41-2.15; p = 0.004). SER+ was positively correlated with oocyte maturation rate, and observed heterogeneity in a previous meta-analysis was likely due to maternal age. Our data also showed that SER+ cycles produced more oocytes but achieved the same number of births from ET.

CONCLUSIONS

The use of SER+ MII oocytes is rare, with the collection of many oocytes in 1 cycle potentially inducing SER+. SER+ may be more common than we originally thought, as some SER+ is found in all oocytes. Although SER+ positively affected oocyte maturation rate, it did not affect births. We hypothesized that this is because the best embryos are chosen at every step of the process, and the oocytes with the poorest characteristics are removed. We therefore suggest a standard method for measuring SER+. Although embryos produced from SER+ cycles can be used, they should only be transferred when no other suitable embryos are available over several cycles.

DYSMORPHISMS OF OOCYTES IN ART PROCEDURES. LITERATURE REVIEW

Currentliterature review presents the analysis of results of studies of morphological qualities and anomalies (dysmorphisms) of human oocytes in the field of assisted reproductive technologies. The variety of intracytoplasmic anomalies encountered in the clinical practice of in vitro fertilization, their effect on fertilization, cleavage, implantation frequency, clinical pregnancy rate were described. Moreover, the morphological characteristics of oocyte could be considered to use as biomarkers in predicting the quality of embryos and blastocysts, and further implantation potential.

Clusters of smooth endoplasmic reticulum are absent in oocytes from unstimulated women

RESEARCH QUESTION

What is the frequency of morphological dysmorphisms in immature human oocytes collected ex vivo from small antral follicles and matured in vitro?

DESIGN

Human ovaries (n = 56) were excised for ovarian tissue cryopreservation (OTC). None of the patients had received exogenous gonadotrophins prior to the procedure. Immature oocytes released from small antral follicles were collected in connection with isolation of the cortex for OTC. The oocytes' maturation stage and the morphological characteristics of the cytoplasm, zona pellucida, perivitelline space and first polar body were assessed after in-vitro maturation (IVM).

RESULTS

A total of 1649 immature oocytes were collected: 30% of oocytes matured to the metaphase II (MII) stage after IVM, while metaphase I (MI), germinal vesicle and degenerated oocytes accounted for 20%, 24% and 26%, respectively. The percentages of oocytes without any dysmorphisms were 53%, 92%, and 97% for the MII, MI and germinal vesicle stage oocytes, respectively. The most frequently observed dysmorphisms among the MII oocytes were first polar body fragmentation (22%), homogeneously distributed cytoplasmic granularity (16%) and an enlarged perivitelline space (14%). Interestingly, none of the oocytes at any stage had clusters of smooth endoplasmic reticulum (SER).

CONCLUSIONS

Morphological dysmorphisms are present among in-vitro-matured oocytes at all maturation stages. The incidence of dysmorphisms increases as maturation progresses. The most frequent dysmorphism among MII oocytes after IVM was fragmentation of the first polar body. Clusters of SER were not observed in oocytes from unstimulated patients.

Oocytes With Smooth Endoplasmic Reticulum Aggregates Are Not Associated With Impaired Reproductive Outcomes: A Matched Retrospective Cohort Study

OBJECTIVE

To investigate whether the reproductive outcomes of oocytes with smooth endoplasmic reticulum aggregates (SERa) are impaired.

METHODS

A total of 2893 intracytoplasmic sperm injection (ICSI) cycles were performed between January 2010 and December 2019 in our center. In 43 transfer cycles, transferred embryos were totally derived from SERa+ oocytes. Each of the 43 cycles was matched with a separate control subject from SERa- patient of the same age ( ± 1 year), embryo condition, main causes of infertility, type of protocols used for fresh or frozen embryo transfer cycles. The clinical pregnancy, implantation, ectopic pregnancy and live birth rate were compared between the two groups.

RESULTS

43 embryo transfer cycles from SERa- patient were matched to the 43 transferred cycles with pure SERa+ oocytes derived embryos. No significant difference was observed in clinical pregnancy rate (55.81% vs. 65.11%, p=0.5081), implantation rate (47.89% vs. 50.70%, p=0.8667) and live birth rate (48.84% vs. 55.81%, p=0.6659) between the SERa+ oocyte group and the matched group. No congenital birth defects were found in the two groups.

CONCLUSION

Our results suggest that the implantation, clinical pregnancy, live birth and birth defects rate of embryos derived from oocytes with SERa are not impaired.

Selection of competent oocytes by morphological criteria for assisted reproductive technologies

Invasive and noninvasive methods are commonly used to select developmentally competent oocytes that can improve the take-home baby rates in assisted reproductive technology (ART) centers. One of the noninvasive methods conventionally utilized to determine competent oocytes is the morphological analysis of cumulus complex, first polar body, zona pellucida, perivitelline space, meiotic spindle, and ooplasm. Successful fertilization, early embryo development, uterine implantation, and healthy pregnancy depend on the quality of oocytes, and morphological evaluation is one of the options used to predict quality levels. In this review, the morphological criteria being utilized in certain ART centers are comprehensively evaluated with special references to their predictive values and potential contributions to selecting high-quality oocytes.

Is it time to reconsider how to manage oocytes affected by smooth endoplasmic reticulum aggregates?

STUDY QUESTION

Did the revised Alpha/ESHRE consensus (Vienna, 2017) bring a real answer on managing oocytes with aggregates of smooth endoplasmic reticulum (SERa)?

SUMMARY ANSWER

According to the currently available literature, a case by case approach on the time of injecting/inseminating SERa+ oocytes may be not helpful for embryologists making a decision, so we suggest fertilizing both SERa+ and SERa- oocytes and prioritizing embryos derived from SERa- oocytes.

WHAT IS KNOWN ALREADY?

In 2011, the Istanbul consensus recommended not to inject/inseminate SER+ oocytes due to adverse foetal outcomes reported in literature. At the end of 2017, a panel of experts reconsidered this recommendation and advised a case by case approach. Hence, with a lack of clear recommendations, in-vitro fertilization practitioners still have heterogeneous attitudes when managing SERa+ oocytes. In this context of controversy, an updated review could be helpful in (i) forming a common language for managing cases of SERa+ oocytes and (ii) offering the most ethical practice and best care for patients seeking infertility treatment or fertility preservation.

STUDY DESIGN, SIZE, DURATION

This review (with a last literature search on 1 June 2018) evaluated the effect of the SER dysmorphism on embryological and neonatal outcomes.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Studies were considered for inclusion if they were prospective or retrospective cohort or case-control studies. Electronic searches of the Pubmed and Embase databases were done using the keyword combination: smooth endoplasmic reticulum, SER, oocyte and zygote. Abstracts and articles written in English and limited to humans were included.

MAIN RESULTS AND THE ROLE OF CHANCE

The search returned a total of 726 studies among which 21 met the inclusion criteria. The literature does not unanimously support a negative association between SERa and embryogenesis, implantation or assisted reproductive therapy outcomes. The reviewed studies reported 112 neonatal outcomes after transfers where at least one embryo originated from oocyte affected by SERa. They included 101 healthy babies, three live births with malformations, three neonatal deaths, one stillbirth and four medical interruptions of pregnancy. After transfer of embryos exclusively derived from SERa+ oocytes, a total of 48 healthy newborns were reported along with four babies with perinatal complications (including one ventricular septal defect), one stillbirth, one neonatal death and one pregnancy termination for multiple malformations.

LIMITATIONS, REASONS FOR CAUTION

As with any review, this review was limited by the quality of the included studies especially in terms of possible methodological limitations, the limited sample size and the retrospective aspect of the studies. Among the 21 selected studies, seven were abstracts and two were case reports. Of the remaining 14 studies, only three were prospective. The tools used in identifying SERa+ oocytes may have varied from one study to another and a consequent misclassification cannot be excluded. Considering the poor resolution of light microscopy in detecting SER aggregates, we are not sure that apparently SERa- oocytes do not really exhibit such a dysmorphism if they were analysed under electronic microscopy or a time lapse system.

WIDER IMPLICATIONS OF THE FINDINGS

In the light of the existing data and the lack of a real link between fertilizing SERa+ oocytes and the occurrence of embryo aneuploidy/malformations, we think that discarding SERa+ oocytes may be not the most ethical approach even in patients with large cohorts on the day of oocyte retrieval. Avoiding the wastage of oocytes and embryos with respect to medical ethics remains a constant concern in daily IVF practice. Thus, we recommend that all mature oocytes could be fertilized and embryos originating from SERa- oocytes would be preferably transferred, even if they come from a cohort with SERa+ oocytes. The remaining embryos derived from SERa+ oocytes could be considered with a lower priority for transfer after obtaining consent from the couple if a strict follow-up of the pregnancy and the baby is performed.

STUDY FUNDING/COMPETING INTEREST(S)

We have no conflict of interest to declare and no funding was received.

REGISTRATION NUMBER

N/A.

A higher incidence of smooth endoplasmic reticulum clusters with aromatase inhibitors

PURPOSE

This study aimed to analyze whether a regimen of aromatase inhibitor (AI) could reduce the occurrence of smooth endoplasmic reticulum clusters (sERCs) in oocytes.

METHODS

The AI and the clomiphene citrate (CC) regimens were compared, regarding the sERC (+) rates and the serum estradiol and progesterone levels on the date of hCG administration, and the duration of AI, CC, and hMG administration.

RESULTS

The occurrence of sERCs in oocytes from patients treated with AI was significantly higher than that in oocytes from those treated with CC. Both the serum estradiol and progesterone levels were found to be significantly higher in sERC (+) than in sERC (-) cycles. With regard to the CC cycles, no significant differences were detected. The duration of AI and hMG administration was longer for sERC (+) than for sERC (-) cycles.

CONCLUSION

As AI did not reduce the occurrence of sERCs, the elevation of estradiol may not be the cause of sERC occurrence but a consequence. Considering the higher levels of progesterone and longer duration of hMG in sERC (+) cycles, the negative effects of premature luteinization, which frequently occur with the AI protocol, should be investigated further.

Platelet-activating factor acetylhydrolase 1B3 (PAFAH1B3) is required for the formation of the meiotic spindle during in vitro oocyte maturation

Platelet-activating factor (PAF) is a well-described autocrine growth factor involved in several reproductive processes and is tightly regulated by its hydrolysing enzyme, PAF acetylhydrolase 1B (PAFAH1B). This intracellular enzyme consists of three subunits: one regulatory, 1B1, and two catalytic, 1B2 and 1B3. PAFAH1B3 has remained uncharacterised until now. Here, we report that PAFAH1B3 is present during the different stages of the first meiotic division in bovine, murine and human oocytes. In these species, the PAFAH1B3 subunit was clearly present in the germinal vesicle, while at metaphase I and II, it localised primarily at the meiotic spindle structure. In cattle, manipulation of the microtubules of the spindle by nocodazole, taxol or cryopreservation revealed a close association with PAFAH1B3. On the other hand, disruption of the enzyme activity either by P11, a selective inhibitor of PAFAH1B3, or by PAFAH1B3 antibody microinjection, caused arrest at the MI stage with defective spindle morphology and consequent failure of first polar body extrusion. In conclusion, our results show that one of the catalytic subunits of PAFAH1B, namely PAFAH1B3, is present in bovine, murine and human oocytes and that it plays a functional role in spindle formation and meiotic progression during bovine oocyte maturation.

Presence of aggregates of smooth endoplasmic reticulum in MII oocytes affects oocyte competence: molecular-based evidence

STUDY QUESTION

Does the presence of aggregates of smooth endoplasmic reticulum (SERa) impact the transcriptome of human metaphase II (MII) oocytes?.

SUMMARY ANSWER

The presence of SERa alters the molecular status of human metaphase II oocytes.

WHAT IS KNOWN ALREADY

Oocytes presenting SERa are considered dysmorphic. Oocytes with SERa (SERa+) have been associated with reduced embryological outcome and increased risk of congenital anomalies, although some authors have reported that SERa+ oocytes can lead to healthy newborns. The question of whether or not SERa+ oocytes should be discarded is still open for debate, and no experimental information about the effect of the presence of SERa on the oocyte molecular status is available.

STUDY DESIGN, SIZE, DURATION

This study included 28 women, aged <38 years, without any ovarian pathology, and undergoing IVF treatment. Supernumerary MII oocytes with no sign of morphological alterations as well as SERa+ oocytes were donated after written informed consent. A total of 31 oocytes without SERa (SERa-) and 24 SERa+ oocytes were analyzed.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Pools of 8-10 oocytes for both group were prepared. Total RNA was extracted from each pool, amplified, labeled and hybridized on oligonucleotide microarrays. Analyses were performed by R software using the limma package.

MAIN RESULTS AND THE ROLE OF CHANCE

The expression profiles of SERa+ oocytes significantly differed from those of SERa- oocytes in 488 probe sets corresponding to 102 down-regulated and 283 up-regulated unique transcripts. Gene Ontology analysis by DAVID bioinformatics disclosed that genes involved in three main biological processes were significantly down-regulated in SERa+ oocytes respective to SERa- oocytes: (i) cell and mitotic/meiotic nuclear division, spindle assembly, chromosome partition and G2/M transition of mitotic cell cycle; (ii) organization of cytoskeleton and microtubules; and (iii) mitochondrial structure and activity. Among the transcripts up-regulated in SERa+ oocytes, the most significantly (P = 0.002) enriched GO term was 'GoLoco motif', including the RAP1GAP, GPSM3 and GPSM1 genes.

LARGE SCALE DATA

Raw microarray data are accessible through GEO Series accession number GSE106222 (https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE106222).

LIMITATIONS, REASONS FOR CAUTION

Data validation in a larger cohort of samples would be beneficial, although we applied stringent criteria for gene selection (fold-change >3 or <1/3 and FDR < 0.1). Surveys on clinical outcomes, malformation rates and follow-up of babies born after transfer of embryos from SERa+ oocytes are necessary.

WIDER IMPLICATIONS OF THE FINDINGS

We provide information on the molecular status of SERa+ oocytes, highlighting possible associations between presence of SERa, altered oocyte physiology and reduced developmental competence. Our study may offer further information that can assist embryologists to make decisions on whether, and with what possible implications, SERa+ oocytes should be used. We believe that the presence of SERa should be still a 'red flag' in IVF practices and that the decision to inseminate SERa+ oocytes should be discussed on a case-by-case basis.

STUDY FUNDING/COMPETING INTEREST(s)

This study was partially supported by Ferring Pharmaceuticals. The authors have no conflicts of interest to declare.

Live Birth Rates in In vitro Fertilization Cycles with Oocytes Containing Smooth Endoplasmic Reticulum Aggregates and Normal Oocytes

Aims:

The aims of this study were to compare the live birth, embryological and pregnancy outcomes after intracytoplasmic sperm injection (ICSI) in patients who have oocytes with smooth endoplasmic reticulum aggregates (SERa+ cycles) and patients with normal oocytes and to compare the pregnancy outcomes based on the observed frequency of SERa.

Settings and Design:

The current study was a retrospective case record review of patients undergoing ICSI from 2012 to 2016 in a specialty fertility center.

Materials and Methods:

The patients were divided into two groups based on the presence of SERa: patients with at least one oocyte containing SERa (SERa+ cycles) (n = 112) and patients with normal oocytes (n = 839). The primary outcome measure was live birth rate. The secondary outcome measures were fertilization rate, cleavage rate, blastocyst formation rate, clinical pregnancy rate, miscarriage rate, and anomalies in children born.

Results:

Women with SERa+ cycles showed similar live birth rates, fertilization rates, cleavage rates, blastocyst formation rates, clinical pregnancy rates, miscarriage rates, and abnormalities in children compared to women with normal oocytes. A gradual reduction in live birth rates was observed when the percentage of oocytes containing SERa increased. The group containing >50% of oocytes with SERa demonstrated no live births.

Conclusions:

Presence of SERa had no major overall negative impact on key embryological and live birth outcomes. A reduction in the live birth rate with increasing proportion of SERa oocytes was observed, with no live births in the group with >50% or all affected oocytes.

Intracellular localisation of platelet-activating factor during mammalian embryo development in vitro: a comparison of cattle, mouse and human

Platelet-activating factor (PAF) is a well-known marker for embryo quality and viability. For the first time, we describe an intracellular localisation of PAF in oocytes and embryos of cattle, mice and humans. We showed that PAF is represented in the nucleus, a signal that was lost upon nuclear envelope breakdown. This process was confirmed by treating the embryos with nocodazole, a spindle-disrupting agent that, as such, arrests the embryo in mitosis, and by microinjecting a PAF-specific antibody in bovine MII oocytes. The latter resulted in the absence of nuclear PAF in the pronuclei of the zygote and reduced further developmental potential. Previous research indicates that PAF is released and taken up from the culture medium by preimplantation embryos invitro, in which bovine serum albumin (BSA) serves as a crucial carrier molecule. In the present study we demonstrated that nuclear PAF does not originate from an extracellular source because embryos cultured in polyvinylpyrrolidone or BSA showed similar levels of PAF in their nuclei. Instead, our experiments indicate that cytosolic phospholipase A2 (cPLA2) is likely to be involved in the intracellular production of PAF, because treatment with arachidonyl trifluoromethyl ketone (AACOCF3), a specific cPLA2 inhibitor, clearly lowered PAF levels in the nuclei of bovine embryos.

Complex chromosomal aberrations in a fetus originating from oocytes with smooth endoplasmic reticulum (SER) aggregates

The presence of smooth endoplasmic reticulum aggregates (SERa) in the ooplasm is considered as the most severe oocyte dysmorphism due to its serious and potentially lethal outcomes in offspring. In the present case report, a couple underwent their first intracytoplasmic sperm injection (ICSI) cycle using a gonadotrophin releasing hormone (GnRH) antagonist protocol, followed by fetal ultrasound scanning and amniocentesis. SERa were observed in all oocytes retrieved. A singleton pregnancy was established. The second trimester fetal ultrasound scan revealed a female fetus with overlapping fingers in both hands, and amniocentesis was performed for the detection of chromosomal abnormalities. Comprehensive genetic analysis with the combined use of array-comparative genomic hybridization (CGH), fluoresence in situ hybridization (FISH) and conventional cytogenetics revealed a complex chromosome rearrangement (CCR) involving three break points on two chromosomes, resulting in a reciprocal translocation with a cryptic 2q31 deletion. A week following amniocentesis, there was rupture of amniotic membranes and a stillborn was delivered. This is the first case in the literature to report a CCR with concomitant 2q31 deletion resulting in a well-defined and clinically recognizable contiguous gene syndrome with an abnormal phenotype in a fetus arising from a cohort of oocytes affected by SERa. It is suggested that fertilization and transfer of oocytes with SERa should be avoided, until further research establishes whether there is a causal relationship between the presence of SERa and chromosomal abnormalities in the resulting fetus.

ABBREVIATIONS

SER: smooth endoplasmic reticulum; ICSI: intracytoplasmic sperm injection; GnRH: gonadotrophin releasing hormone; CGH: comparative genomic hybridization; FISH: fluoresence in situ hybridization; FSH: follicle stimulating hormone; hCG: human chorionic gonadotrophin; OHSS: ovarian hyperstimulation syndrome; IVF: in vitro fertilization; MII: metaphase II; GV: germinal vesicle; CCR: complex chromosome rearrangement.

A higher incidence of cleavage failure in oocytes containing smooth endoplasmic reticulum clusters

PURPOSE

In human oocytes, sERCs are one of the dysmorphic phenotypes that have been reported. Significantly reduced pregnancy rates and a comparatively higher number of abnormities in live births appear to be associated with the presence of sERCs in oocytes. However, some reports have shown that healthy babies can be born, without any reduced pregnancy rates, from oocytes observed to contain sERCs. Thus, the clinical and scientific significance of oocytes that harbor sERCs remains controversial.

METHODS

The presence of sERCs was evaluated using a time-lapse system while studying the dynamic changes within oocytes and embryos. Logistic regression analysis was carried out to explore the independent variables for meiotic and mitotic cleavage failure..

RESULTS

The incidence of mitotic cleavage failure and the incidence of meiotic cleavage failure during the second polar body extrusion in oocytes with sERCs were found to be significantly higher than that in oocytes without sERCs. Furthermore, ICSI was found to have a greater frequency of meiotic failure than IVF.

CONCLUSIONS

In cases of cleavage failure, an embryonic cell could become tetraploid and may induce abnormal chromosomal configurations. Some cells exposed to cleavage failure may become trophectoderm cells and form placental abnormalities. Even if they develop into trophectoderm cells, the ICM can be susceptible to further cleavage failure and may in turn cause further aneuploidy. For these reasons, it is important to monitor pregnancies and births derived from oocytes that contained sERCs.

Dysmorphic patterns are associated with cytoskeletal alterations in human oocytes

Study question

Are specific morphological anomalies in human mature oocytes, as revealed by transmitted light microscopy, associated with intrinsic damage to the meiotic spindle and actin cytoskeleton?

Summary answer

Aggregates of smooth endoplasmic reticulum (SER) and domains of centrally localized granular cytoplasm (GC) reflect intrinsic damage to the oocyte cytoskeleton, namely alterations in spindle size, chromosome misalignment and cortical actin disorganization.

What is known already

In preparation for ICSI, oocytes are often selected for use in treatment by morphological criteria, but the rationale and implications of this practice are controversial. Very little information is available on the relationship between oocyte morphology and intrinsic cellular characteristics, such as the actin cytoskeleton, meiotic spindle and chromosome alignment.

Study design, size, duration

A total of 170 metaphase II (MII) oocytes were donated by consenting IVF patients and analysed; 62 were classified as morphologically normal (control), 54 had SER clusters and 54 had centrally localized GC.

Participants/materials, setting, methods

Supernumerary oocytes were fixed within 3 h from recovery and stained for tubulin, chromatin and actin. Spindles were analysed for 1D and 2D characteristics by high-performance confocal microscopy. Chromosomes were classified as scattered or aligned and the conformation and intensity of cortical actin was evaluated.

Main results and the role of chance

In comparison with control oocytes, both SER and GC oocytes showed greater spindle length (P = 0.033 and 0.003, respectively) and GC oocytes also showed greater spindle width (P= 0.049) and area (P= 0.036). Control and SER oocytes had statistically comparable rates of chromosome displacement from the metaphase plate, unlike GC oocytes where chromosome displacement occurred at higher rate (P = 0.013). In situations where a complete Z-stack was reconstructed from a polar angle, chromosome disposition was classified as being normal when two sets of concentric arrays were visible. Based on these parameters, the proportions of oocytes with normal chromosomal arrangement or partial/total disarrangement was not statistically different between control and SER oocytes. Conversely, in GC oocytes, chromosome disarrangement was higher (P = 0.002). All control oocytes displayed a continuous meshwork of suboolemmal actin, which appeared as an uninterrupted ring in thin optical sections. In contrast, in SER and  GC groups, integrity of suboolemmal actin was observed in only 66.7 and 42.9% of oocytes, respectively (P = 0.0001).

Large scale data

N/A.

Limitations reason for caution

Only two of several known oocyte dysmorphisms were investigated, while oocyte quality was assessed only by cytoskeletal criteria.

Wider implications of the findings

This study represents a significant step toward a more objective assessment of oocyte morphology, offering information that can assist embryologists to make a more aware and rationally founded decision on whether, and with what possible implications, oocytes with certain dysmorphic characters should be used for treatment or discarded. More generally, it also demonstrates that morphometric parameters of the cytoskeleton and chromosome organization can be used as biomarkers of oocyte quality.

Study funding and competing interest(s)

This study was funded by Biogenesi Reproductive Medicine Centre (Monza, Italy). All authors declare no conflict of interests.

Clinical outcomes after IVF or ICSI using human blastocysts derived from oocytes containing aggregates of smooth endoplasmic reticulum

In this study the clinical and neo-natal outcomes after transfer of blastocysts derived from oocytes containing aggregates of smooth endoplasmic reticulum (SER) were compared between IVF and intracytoplasmic sperm injection (ICSI) cycles. Clinical and neo-natal outcomes of blastocysts in cycles with at least one SER metaphase II oocyte (SER + MII; SER + cycles) did not significantly differ between the two insemination methods. When SER + MII were cultured to day 5/6, fertilization, embryo cleavage and blastocyst rates were not significantly different between IVF and ICSI cycles. In vitrified-warmed blastocyst transfer cycles, the clinical pregnancy rates from SER + MII in IVF and ICSI did not significantly differ. In this study, 52 blastocysts (27 IVF and 25 ICSI) derived from SER + MII were transferred, yielding 15 newborns (5 IVF and 10 ICSI) and no malformations. Moreover, 300 blastocysts (175 IVF and 125 ICSI) derived from SER-MII were transferred, yielding 55 newborns (24 IVF and 31 ICSI cycles). Thus, blastocysts derived from SER + cycles exhibited an acceptable ongoing pregnancy rate after IVF (n = 125) or ICSI (n = 117) cycles. In conclusion, blastocysts from SER + MII in both IVF and ICSI cycles yield adequate ongoing pregnancy rates with neo-natal outcomes that do not differ from SER-MII.

Oocytes with smooth endoplasmic reticulum clusters originate blastocysts with impaired implantation potential

OBJECTIVE

To study whether embryos derived from oocytes presenting a smooth endoplasmic reticulum cluster (SERC) are less likely to develop into blastocysts and implant.

DESIGN

Transversal study.

SETTING

Private university-affiliated in vitro fertilization (IVF) center.

PATIENT(S)

Total of 7,609 oocytes obtained from 743 intracytoplasmic sperm injection (ICSI) cycles.

INTERVENTION(S)

Oocytes split between the SERC-positive cycles (with at least one SERC-positive oocyte) and the SERC-negative cycles (only oocytes free of SERC).

MAIN OUTCOME MEASURE(S)

Embryo implantation.

RESULT(S)

A statistically significantly higher mean number of follicles (24.0 ± 10.5 vs. 19.6 ± 10.5), retrieved oocytes (17.8 ± 8.3 vs. 14.3 ± 8.0), and mature oocytes (13.5 ± 6.2 vs. 10.6 ± 5.9) were observed in the SERC-positive cycles as compared with SERC-negative cycles. The implantation rate was statistically significantly lower in SERC-positive cycles as compared with SERC-negative cycles (14.8% vs. 25.6%; odds ratio 0.61; 95% confidence interval, 0.44-0.86). When only cycles with in which none (0) or all the blastocysts transferred had implanted (100%) were analyzed, the mean implantation rate per transferred blastocyst in the SERC-negative group was 20.5%; no blastocysts derived from SERC-positive oocytes implanted.

CONCLUSION(S)

The occurrence of SERC impairs embryo implantation. Careful oocyte observation that takes into account the presence of SERC should be part of embryo selection strategy before transfer.

Ultrastructural and cytogenetic analyses of mature human oocyte dysmorphisms with respect to clinical outcomes

PURPOSE

The study aimed to describe the ultrastructure of two human mature oocyte intracytoplasmic dysmorphisms, the bull-eye inclusion and the granular vacuole, with evaluation of clinical outcomes after intracytoplasmic sperm injection (ICSI) treatment.

METHODS

We retrospectively evaluated 4099 consecutive ICSI cycles during the period 2003-2013. Three groups were compared: controls, those with a bulls-eye inclusion, and those with granular vacuoles. Oocyte dysmorphisms were evaluated by transmission electron microscopy and in situ fluorescence hybridization (FISH). Detailed data on demographic and stimulation characteristics, as well as on embryological, clinical, and newborn outcomes, are fully presented.

RESULTS

The bull-eye inclusion is a prominent smooth round structure containing trapped vesicles, being surrounded by lipid droplets. The presence of this dysmorphism in the oocyte cohort had no clinical impact except when transferred embryos were exclusively derived from dysmorphism oocytes. The granular vacuole is delimited by a discontinuous double membrane and contains lipid droplets and vesicles. As FISH analysis revealed the presence of chromosomes, they probably represent pyknotic nuclei. The presence of this dysmorphism in the oocyte cohort had no clinical impact except when at least one transferred embryo was derived from dimorphic oocytes.

CONCLUSIONS

Poor clinical outcomes were observed with transfer of embryos derived from dysmorphism oocytes, although without causing gestation or newborn problems. The bull-eye inclusion and granular vacuoles may thus be new prognostic factors for clinical outcomes.

Oocytes affected by smooth endoplasmic reticulum aggregates: to discard or not to discard?

PURPOSE

Oocytes containing smooth endoplasmic reticulum aggregates (SERa) have been associated with reduced fertilization and clinical pregnancy rates as well as compromised neonatal outcomes. It was therefore recommended by an Alpha-ESHRE Consensus to discard oocytes presenting this dysmorphism. The data in the literature are nevertheless conflicting and healthy babies have recently been obtained from affected oocytes. The objectives of this study were to compare clinical outcomes between ICSI cycles with and without oocytes affected by smooth endoplasmic reticulum aggregates and to confirm whether affected oocytes can produce healthy babies.

METHODS

A prospective observational study was performed comparing 714 SERa- ICSI cycles to 112 SERa+ cycles. Among the SERa+ cycles, 518 SERa- oocytes and 213 SERa+ oocytes were analyzed. Fertilization, embryo quality, and pregnancy rates as well as neonatal outcomes were compared between SERa+ and SERa- cycles as well as between SERa+ and SERa- oocytes.

RESULTS

The presence of SERa was not associated with an adverse effect on embryological, clinical or neonatal data for SERa+ cycles and oocytes. Seven healthy babies were born from embryos originating from SERa+ oocytes.

CONCLUSIONS

These results are encouraging and might contribute in the future to a revision of the Alpha-ESHRE Consensus. Larger studies, including a correlation between frequency and size of SERa, clinical outcomes and malformation rates, as well as the follow-up of babies born are nevertheless necessary. In the meantime, the currently conflicting data requires caution when considering transfers of embryos affected by SERa.

Embryological outcomes in cycles with human oocytes containing large tubular smooth endoplasmic reticulum clusters after conventional in vitro fertilization

There have been no studies analyzing the effect of large aggregates of tubular smooth endoplasmic reticulum (aSERT) after conventional in vitro fertilization (cIVF). The aim of this study was to investigate whether aSERT can be identified after cIVF and the association between the embryological outcomes of oocytes in cycles with aSERT. This is a retrospective study examining embryological data from cIVF cycles showing the presence of aSERT in oocytes 5-6 h after cIVF. To evaluate embryo quality, cIVF cycles with at least one aSERT-metaphase II (MII) oocyte observed (cycles with aSERT) were compared to cycles with normal-MII oocytes (control cycles). Among the 4098 MII oocytes observed in 579 cycles, aSERT was detected in 100 MII oocytes in 51 cycles (8.8%). The fertilization rate, the rate of embryo development on day 3 and day 5-6 did not significantly differ between cycles with aSERT and control group. However, aSERT-MII oocytes had lower rates for both blastocysts and good quality blastocysts (p < 0.05). aSERT can be detected in the cytoplasm by removing the cumulus cell 5 h after cIVF. However, aSERT-MII oocytes do not affect other normal-MII oocytes in cycles with aSERT.

The impact of Alpha/ESHRE consensus regarding oocytes with aggregates of smooth endoplasmic reticulum (SERa) on in vitro fertilization outcome

PURPOSE

The present study aimed to gather information on the impact of Alpha/European Society of Human Reproduction and Embryology (ESHRE) consensus regarding oocytes with aggregates of smooth endoplasmic reticulum (SERa) on in vitro fertilization outcome. In particular, we investigated if patients undergoing intracytoplasmic sperm injection (ICSI) and whose oocytes are discarded due to SERa have a higher chance of embryo transfer cancellation compared to patients without SERa oocytes.

METHODS

This is a nested case-control study drawn from the cohort of women referring for in vitro fertilization with ICSI. Cases were patients showing at least one oocyte with SERa at the time of injection. Controls were subsequent patients showing no SERa oocytes and matched ratio 1:1 for age, clinical indication to in vitro fertilization (IVF), and body mass index. The main outcome was the rate of embryo transfer cancellation.

RESULTS

The percentage of women experiencing a transfer cancellation (absence of suitable oocytes or viable embryos) in their ICSI cycle were significantly higher in cases (18 %) compared to controls (8 %) (p = 0.02); however, adjusted odds ratio for FSH and number of SERa oocytes, of follicles, of retrieved oocytes, and of inseminated oocytes were not statistically significant.

CONCLUSIONS

We have shown that the exclusion of SERa oocytes from ICSI cycles causes an increased frequency of transfer cancellation. This effect is mostly due to the reduced number of available oocytes after exclusion of SERa oocytes.

Effect of oocyte dysmorphisms on intracytoplasmic sperm injection cycle outcomes in normal ovarian responders

AIM

The aim of this study was to identify the influence of oocyte dysmorphisms on clinical outcomes after intracytoplasmic sperm injection cycle in normal responders.

MATERIAL AND METHODS

In the prospective study, morphology of 1999 metaphase II oocytes retrieved from 316 intracytoplasmic sperm injection cycles was evaluated from March 2011 to March 2013 at Royan Institute. Controlled ovarian stimulation was performed by long standard agonist protocol. Oocyte morphology was assessed before sperm injection by one embryologist. The associations between fertilization rate, embryo quality and the independent variables were analyzed using odds ratio (OR) calculated with unconditional logistic regression test.

RESULTS

From all retrieved oocytes, 1543 (77.1%) showed at least one morphologic aberration. Presence of cytoplasmic vacuoles and high cytoplasmic viscosity were associated with a significant decrease in the fertilization rate (OR: 0.5; P = 0.004 and OR: 0.6; P = 0.03, respectively). The results showed that oocyte morphology did not affect embryo quality. The number of gonadotrophin injections used showed a direct relation with presence of large perivitelline space. No significant difference was observed among four groups (women with total normal morphologic oocytes [group 1], women with total extracytoplasmic dysmorphic oocytes [group 2], women with total cytoplasmic dysmorphic oocytes [group 3] and women with total oocytes containing multiple dysmorphic features [group 4]) in terms of implantation and clinical pregnancy rates.

CONCLUSIONS

Metaphase II oocyte morphology had minor impacts on fertilization rate, pronuclear morphology and embryo quality in women with normal ovarian response.

Ultrastructural markers of quality are impaired in human metaphase II aged oocytes: a comparison between reproductive and in vitro aging

PURPOSE

Childbearing delay contributes to the increase of subfertile couples that require assisted reproductive technology (ART). Subfertility relates with reproductive aging (RA). In vitro aging (IvA) (due to extended culture) may also impair oocyte competence. Aims of this study were to evaluate and compare the oocyte ultrastructure after RA and IvA.

METHODS

Cumulus-oocyte complexes (COCs) (n = 68), with metaphase II oocyte and expanded cumulus, from consenting patients (<35 years old and ≥35 years old, n = 36), were selected by phase contrast microscopy and fixed at pick up, or after 24 h culture. COCs (n = 44) were studied by light and qualitative/morphometric transmission electron microscopy. Two-way ANOVA, with age and culture as grouping factors, was applied for statistical analysis (p < 0.05). Metaphase II cumulus-free oocytes (n = 24) were selected for confocal microscopy observations.

RESULTS

Significant decrease of mitochondria-smooth endoplasmic reticulum aggregates, increase of mitochondria-vesicle complexes size and amount, decrease of cortical granules and microvilli, and alterations of the spindle structure characterized both RA and IvA oocytes. These changes were significantly more evident in the RA oocytes submitted to IvA. RA oocytes also showed changes of the zona pellucida and occurrence of vacuoles after culture. Cumuli appeared re-compacted after culture, irrespective of the age of the patients.

CONCLUSIONS

These data demonstrated that aging is related to decay of oocyte ultrastructural quality, and that oocytes from elder women are more sensitive to prolonged culture (IvA) than the oocytes from younger women. These morphological results should be considered when applying ART in aged patients, rescue ICSI, or artificial oocyte activation.

Policy of IVF centres towards oocytes affected by Smooth Endoplasmic Reticulum aggregates: a multicentre survey study

PURPOSE

The presence of Smooth Endoplasmic Reticulum aggregates (SERa) has been reported to be associated with adverse outcomes. An Alpha-ESHRE Consensus was published in 2011, strongly recommending to not inseminating affected oocytes. On the other hand, healthy babies have been born from oocytes presenting this dysmorphism. We surveyed several European IVF centres, to assess their attitudes concerning affected oocytes.

METHODS

This survey is based on a computer format and includes questions regarding the fate of affected oocytes.

RESULTS

About 14 % of centres who answered our survey discard SERa+ oocytes. 43 % of centres that do not discard the oocytes, register and follow up neonatal data. About a quarter of centres inform their patients about this dysmorphism. Half of them require an informed consent prior to transferring affected embryos. Twenty-one centres reported having SERa+ births, with one reporting a malformation. 48 % of centres declared having been influenced by the Alpha-ESHRE Consensus, in their management policy of SERa+ oocytes.

CONCLUSIONS

Few centres scrupulously respect the recommendations of the Alpha-ESHRE Consensus and discard affected oocytes. Since it is essential to determine if there truly is an impact of this dysmorphism and whether the guidelines are still valid, transfer of affected embryos should only be done when accompanied with data recording and monitoring of all foetal malformations from IVF. Clarifying the situation will allow IVF centres to correctly inform patients about the risk of birth malformations as well as whether a decreased chance of pregnancy exists.

Oocyte maturation: gamete-somatic cells interactions, meiotic resumption, cytoskeletal dynamics and cytoplasmic reorganization

BACKGROUND

In a growth phase occurring during most of folliculogenesis, the oocyte produces and accumulates molecules and organelles that are fundamental for the development of the preimplantation embryo. At ovulation, growth is followed by a phase of maturation that, although confined within a short temporal window, encompasses modifications of the oocyte chromosome complement and rearrangements of cytoplasmic components that are crucial for the achievement of developmental competence. Cumulus cells (CCs) are central to the process of maturation, providing the oocyte with metabolic support and regulatory cues.

METHODS

PubMed was used to search the MEDLINE database for peer-reviewed original articles and reviews concerning oocyte maturation in mammals. Searches were performed adopting 'oocyte' and 'maturation' as main terms, in association with other keywords expressing concepts relevant to the subject. The most relevant publications, i.e. those concerning major phenomena occurring during oocyte maturation in established experimental models and the human species, were assessed and discussed critically to offer a comprehensive description of the process of oocyte maturation.

RESULTS

By applying the above described search criteria, 6165 publications were identified, of which 543 were review articles. The number of publications increased steadily from 1974 (n = 7) to 2013 (n = 293). In 2014, from January to the time of submission of this manuscript, 140 original manuscripts and reviews were published. The studies selected for this review extend previous knowledge and shed new and astounding knowledge on oocyte maturation. It has long been known that resumption of meiosis and progression to the metaphase II stage is intrinsic to oocyte maturation, but novel findings have revealed that specific chromatin configurations are indicative of a propensity of the oocyte to resume the meiotic process and acquire developmental competence. Recently, genetic integrity has also been characterized as a factor with important implications for oocyte maturation and quality. Changes occurring in the cytoplasmic compartment are equally fundamental. Microtubules, actin filaments and chromatin not only interact to finalize chromosome segregation, but also crucially co-operate to establish cell asymmetry. This allows polar body extrusion to be accomplished with minimal loss of cytoplasm. The cytoskeleton also orchestrates the rearrangement of organelles in preparation for fertilization. For example, during maturation the distribution of the endoplasmic reticulum undergoes major modifications guided by microtubules and microfilaments to make the oocyte more competent in the generation of intracellular Ca(2+) oscillations that are pivotal for triggering egg activation. Cumulus cells are inherent to the process of oocyte maturation, emitting regulatory signals via direct cell-to-cell contacts and paracrine factors. In addition to nurturing the oocyte with key metabolites, CCs regulate meiotic resumption and modulate the function of the oocyte cytoskeleton.

CONCLUSIONS

Although the importance of oocyte maturation for the achievement of female meiosis has long been recognized, until recently much less was known of the significance of this process in relation to other fundamental developmental events. Studies on chromatin dynamics and integrity have extended our understanding of female meiosis. Concomitantly, cytoskeletal and organelle changes and the ancillary role of CCs have been better appreciated. This is expected to inspire novel concepts and advances in assisted reproduction technologies, such as the development of novel in vitro maturation systems and the identification of biomarkers of oocyte quality.

Expression and intracytoplasmic distribution of staufen and calreticulin in maturing human oocytes

PURPOSE

In this study we hypothesized that the mRNA vector Staufen mediates RNA relocalization during meiotic maturation, and by virtue of its interactions with endoplasmic reticulum, provides a possible mechanism by which protein synthesis is regulated.

METHODS

We assessed the expression of staufen (STAU) and calreticulin (CALR), the latter adopted as a marker of the endoplasmic reticulum, in human oocytes at different stages of maturation: GV, metaphase MI and MII. Oocytes were subjected to polymerase chain reaction in order to investigate the expression of STAU and CALR. The corresponding protein products were identified by immunofluorescence and confocal laser scanning microscopy.

RESULTS

STAU and CALR were constantly expressed and selectively localized during oocyte maturation. At the GV stage the both proteins displayed a dispersed distribution localization throughout the cytoplasm. Progressing to the MII stage, STAU tended to compartmentalize towards the cortical area of the oocyte clustering in granules of larger sizes. At the MII stage, CALR assumed a pattern reminiscent and possibly coincident with the position of the meiotic spindle.

CONCLUSIONS

The changing pattern of STAU distribution during meiotic maturation of human oocytes implicates a novel mechanism for the regulation of protein synthesis based on mRNA localization. Moreover, the unique disposition of CALR at the MII spindle uncovers a physical interaction with endoplasmic reticulum that may mediate cytoskeletal remodelling during oocyte maturation.

Oocyte environment: follicular fluid and cumulus cells are critical for oocyte health

Bidirectional somatic cell-oocyte signaling is essential to create a changing intrafollicular microenvironment that controls primordial follicle growth into a cohort of growing follicles, from which one antral follicle is selected to ovulate a healthy oocyte. Such intercellular communications allow the oocyte to determine its own fate by influencing the intrafollicular microenvironment, which in turn provides the necessary cellular functions for oocyte developmental competence, which is defined as the ability of the oocyte to complete meiosis and undergo fertilization, embryogenesis, and term development. These coordinated somatic cell-oocyte interactions attempt to balance cellular metabolism with energy requirements during folliculogenesis, including changing energy utilization during meiotic resumption. If these cellular mechanisms are perturbed by metabolic disease and/or maternal aging, molecular damage of the oocyte can alter macromolecules, induce mitochondrial mutations, and reduce adenosine triphosphate production, all of which can harm the oocyte. Recent technologies are now exploring transcriptional, translational, and post-translational events within the human follicle with the goal of identifying biomarkers that reliably predict oocyte quality in the clinical setting.

Deliveries of babies with normal health derived from oocytes with smooth endoplasmic reticulum clusters

PURPOSE

To examine the impact on development of derived embryos from smooth endoplasmic reticulum clusters (SERC) in human metaphase II (MII) oocytes.

METHODS

Retrospective analysis at Kyono ART Clinic. Comparison of embryological development, pregnancy, live birth and fetal malformation between oocytes with SERC (the SERC(+) group) and those without (the SERC(-) group) in 2,158 patients (3,758 cycles) after ICSI.

RESULTS

Fertilization and implantation rate were significantly lower in SERC(+) MII oocytes than in SERC(-) MII oocytes. After the transfer of fresh and vitrified embryos derived from SERC(+) oocytes, 14 pregnancies resulted in 14 healthy babies, including 2 from fresh embryo transfer (ET) and 12 from vitrified-warmed ET, with no malformations.

CONCLUSION(S)

The presence of SERC in MII oocytes was associated with significantly lower fertilization rates and implantation rates than seen in SERC(-) MII oocytes within SERC (+) cycles. However, SERC had no impact on post-implantation development as well as neonatal outcome.

Health outcomes of children born after IVF/ICSI: a review of current expert opinion and literature

The Sixth Evian Annual Reproduction (EVAR) Workshop Group Meeting was held to evaluate the impact of IVF/intracytoplasmic sperm injection on the health of assisted-conception children. Epidemiologists, reproductive endocrinologists, embryologists and geneticists presented data from published literature and ongoing research on the incidence of genetic and epigenetic abnormalities and congenital malformations in assisted-conception versus naturally conceived children to reach a consensus on the reasons for potential differences in outcomes between these two groups. IVF-conceived children have lower birthweights and higher peripheral fat, blood pressure and fasting glucose concentrations than controls. Growth, development and cognitive function in assisted-conception children are similar to controls. The absolute risk of imprinting disorders after assisted reproduction is less than 1%. A direct link between assisted reproduction and health-related outcomes in assisted-conception children could not be established. Women undergoing assisted reproduction are often older, increasing the chances of obtaining abnormal gametes that may cause deviations in outcomes between assisted-conception and naturally conceived children. However, after taking into account these factors, it is not clear to what extent poorer outcomes are due to the assisted reproduction procedures themselves. Large-scale, multicentre, prospective epidemiological studies are needed to investigate this further and to confirm long-term health consequences in assisted-conception children. Assisted reproduction treatment is a general term used to describe methods of achieving pregnancy by artificial means and includes IVF and sperm implantation. The effect of assisted reproduction treatment on the health of children born using these artificial methods is not fully understood. In April 2011, fertility research experts met to give presentations based on research in this area and to look carefully at the evidence for the effects of assisted reproduction treatment on children's health. The purpose of this review was to reach an agreement on whether there are differences in the health of assisted-conception children with naturally conceived children. The researchers discovered no increased risk in birth defects in assisted-conception children compared with naturally conceived children. They found that IVF-conceived children have lower birth weights and higher fat under the skin, higher blood pressure and higher fasting glucose concentrations than naturally conceived children; however, growth, development and cognitive function are similar between groups. A very low risk of disorders of genetic control was observed in assisted-conception children. Overall, there did not appear to be a direct link between assisted reproduction treatment and children's health. The researchers concluded that the cause of some differences in the health of children conceived using assisted reproduction treatment may be due to the age of the woman receiving treatment. Large-scale, research studies are needed to study the long-term health of children conceived using assisted reproduction treatment.