Detrimental effects of endometriosis on oocyte morphology in intracytoplasmic sperm injection cycles: a retrospective cohort study

Impact of endometriosis on the ovarian follicles

A significant body of evidence has supported a negative impact of endometriosis on ovarian follicles; however, the origin and relevance of this ovarian impairment in endometriosis is still a matter of debate. The ovarian damage can be caused by endometriosis itself or by surgeries aiming to remove endometriotic lesions. In this review, we summarized the existing knowledge on the mechanisms by which endometriosis can impact the ovarian follicles, from molecular to clinical points of view. From a molecular standpoint, the presence of endometriosis or its consequences can induce oxidative stress, inflammation, aberrant mitochondrial energy metabolism and inappropriate steroid production in granulosa cells, phenomena that may impair the quality of oocytes to variable degrees. These alterations may have clinical relevance on the accelerated exhaustion of the ovarian reserve, on the ovarian response to gonadotrophin stimulation in IVF cycles and on the competence of the oocytes. Critical points to be considered in current clinical practices related to fertility issues in endometriosis are discussed.

Effects of different oocyte cytoplasmic granulation patterns on embryo development and euploidy: a sibling oocyte control study

PURPOSE

This study evaluated the relationship between cytoplasmic granulation patterns and the developmental potential of mature sibling oocytes.

METHODS

Data from 54 cycles of preimplantation genetic tests for structural rearrangement from July 2019 to June 2022 were analyzed. In total, 564 embryos were cultured using a time-lapse system. Sibling oocytes were divided into four groups based on cytoplasmic granulation patterns: fine granulation (FG) group (n = 177), central granulation (CG) group (n = 183), dispersed granulation (DG) group (n = 161), and uneven granulation (UG) group (n = 43). The CG group was further divided into three groups (grades I, II, and III) based on the tertile of the ratio of central granular distribution area to oocyte area. Fertilization rate, embryo morphokinetics, chromosomal ploidy, and clinical outcomes of the groups were compared.

RESULTS

No significant differences were observed in morphokinetic parameters, fertilization rate, embryo production, blastocyst formation, and aneuploidy rates among the different cytoplasmic-granulation pattern groups. However, embryos derived from CG oocytes showed significantly higher aneuploidy rates in grade III compared to grade I (86.21% vs 61.54%, P = 0.036) or grade II (86.21% vs 56.00%, P = 0.013). Thirty embryos were transferred to the uteri of female patients and the clinical pregnancy and live birth rates did not significantly differ among groups.

CONCLUSIONS

Cytoplasmic granulation patterns may not affect embryo fertilization, development speed, and aneuploidy rates. However, a higher grade of CG may be associated with increased aneuploidy rates. Larger sample sizes are required to explore the impact of oocyte cytoplasmic granulation patterns on embryo implantation potential.

Decreased oocyte quality in patients with endometriosis is closely related to abnormal granulosa cells

Infertility and menstrual abnormalities in endometriosis patients are frequently caused by aberrant follicular growth or a reduced ovarian reserve. Endometriosis typically does not directly harm the oocyte, but rather inhibits the function of granulosa cells, resulting in a decrease in oocyte quality. Granulosa cells, as oocyte nanny cells, can regulate meiosis, provide the most basic resources required for oocyte development, and influence ovulation. Endometriosis affects oocyte development and quality by causing granulosa cells apoptosis, inflammation, oxidative stress, steroid synthesis obstacle, and aberrant mitochondrial energy metabolism. These aberrant states frequently interact with one another, however there is currently relatively little research in this field to understand the mechanism of linkage between abnormal states.

Endometriosis, Oocyte, and Embryo Quality

Endometriosis is a common finding among women with infertility, and women who are diagnosed with endometriosis are almost twice as likely to experience infertility. Mechanisms by which endometriosis causes infertility remain poorly understood. In this review, we evaluate the current literature on the impact of endometriosis on oocyte and embryo quality. The presence of endometriosis evidently reduces ovarian reserve, oocyte quality, and embryo quality; however, this does not appear to translate to a clear clinical impact. Analysis of data from large assisted reproduction technology registries has shown that women with endometriosis have a lower oocyte yield but no reduction in reproductive outcomes. There is a need for future studies in the form of well-designed randomized controlled trials to further evaluate the role of surgical and medical treatment options in women with endometriosis undergoing assisted conception.

Bioinformatic analysis confirms differences in circular RNA expression profiles of cumulus cells between patients with ovarian and peritoneal endometriosis-associated infertility

Endometriosis has a detrimental effect on oocyte quality, and ovarian endometriosis (OEM) and peritoneal endometriosis (PEM) may have different effects on female fertility. Therefore, we conducted a study to explore the circular RNA (circRNA) expression profiles of cumulus cells (CCs) in patients with OEM (n = 3), PEM (n = 3), and tubal factor infertility (TFI, n = 3) using high-throughput sequencing techniques and attempted to identify common and unique circRNAs in the OEM and PEM groups. The CIRCexplorer2 program was used to identify circRNAs. Seven candidate circRNAs were validated in 30 samples using quantitative real-time polymerase chain reaction (qRT-PCR). Finally, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed to annotate the function of circRNA-targeted genes, which were verified by sequencing results and constructed circRNA-miRNA-mRNA networks. A total of 11833 circRNAs were identified in nine samples. The numbers of differentially expressed circRNAs between the OEM and TFI groups, PEM and TFI groups, and OEM and PEM groups were 130, 71, and 191, respectively. After taking intersections, 11 circRNAs were considered common circRNAs in the OEM and PEM groups; 39 circRNAs in the OEM group and 17 circRNAs in the PEM group were identified as unique key circRNAs. During qRT-PCR validation, hsa_circ_0003638 was significantly upregulated in the PEM group compared to that in the OEM and TFI groups. Functional analysis of circRNA-targeted genes revealed that apoptosis, PI3K-AKT, and p53 signaling pathways were enriched in the PEM-TFI comparison groups, whereas the functions of target genes involved in the JAK-STAT and TGF-β signaling pathways were enriched in the PEM-OEM comparison groups. Our findings confirmed differences in circRNA expression profiles of CCs between patients with OEM and PEM infertility and provide new insights into the different effects of various endometriosis phenotypes on oocytes.

Impact of endometriosis on embryo quality and endometrial receptivity in women undergoing assisted reproductive technology

ART is an important treatment method for infertile patients with endometriosis. However, the effects of endometriosis on embryo quality and endometrial receptivity remain unclear. Thus, we aimed to simultaneously investigate the impact of endometriosis and its stage on embryo quality and endometrial receptivity in women undergoing ART. We retrospectively analyzed the data from patients with and without endometriosis who underwent oocyte retrieval and/or high-quality embryos transfer between July 2015 and December 2020, including 1312 IVF cycles and 608 IVF or frozen-thawed embryo transfer (FET) cycles, respectively. The endometriosis group had a lower percentage of good cleavage-stage embryos and fertilization rates than those in the control group (p = 0.038 and 0.008, respectively). The number of retrieved oocytes, MII oocytes, cleavage, blastocysts, and blastulation rates was comparable between two groups. We found no significant difference in clinical pregnancy, implantation, live birth, miscarriage, or multiple pregnancy rates between the two groups among patients who transferred high-quality embryos. Stratification analysis showed that patients with stage III-IV endometriosis had fewer retrieved oocytes than those with stage I-II endometriosis (p = 0.012) and marginally fewer retrieved oocytes than the control group (p = 0.051). The stage I-II group had the lowest percentage of good cleavage-stage embryos, which was significantly lower than that of the control group (p = 0.043). In FET cycles, patients with stage III-IV endometriosis had a higher miscarriage rate than those in the control group (p = 0.023). Our results suggest that endometriosis does not alter endometrial receptivity but affects embryo quality, oocyte fertilization ability, and ovarian response.

The Kisspeptin and Kisspeptin receptor in follicular microenvironment: is that really necessary for oocyte maturation and fertilisation?

The aim of this study was to determine whether Kisspeptin and Kisspeptin receptor in the follicular microenvironment is necessary for human oocyte maturation and fertilisation. The cumulus cell (CC) and follicle fluids (FF) obtained from the first aspirated follicles (n = 52) from 32 patients were divided into three groups considering nuclear maturation and fertilisation results of oocytes: (1) Metaphase I or germinal vesicle stage oocytes (incomplete nuclear maturation, n = 10), (2) unfertilised metaphase II oocytes (incomplete cytoplasmic maturation, n = 16), and (3) fertilised metaphase II oocytes (completed nuclear-cytoplasmic maturation, n = 26). The gene expression levels were assessed by RT-PCR. The levels of Kisspeptin (KISS1) and Kisspeptin receptor (KISS1R) were measured by ELISA. There were no significant efficacy KISS1 and KISS1R gene expressions in cumulus cells in terms of oocyte nuclear maturation stage (Group 1, vs Group 2 + Group 3) (respectively p = .49; p = .45). In terms of the cytoplasmic maturation stage (Group 2, vs Group 3); KISS1 and KISS1R expressions in CCs were comparable (respectively p = .07; p = .08). In FFs, KISS1 and KISS1R concentrations were similar between all groups (respectively p = .86; p = .26). In conclusion, the relative KISS1 and KISS1R expressions in CC and also KISS1 and KISS1R level of FF were independent of oocytes nuclear and/or cytoplasmic maturation. Impact statementWhat is already known on this subject? It has been demonstrated that Kisspeptin is an essential regulator of reproductive function and plays a key role in the modulation of GnRH secretion and gonadotropin release. Still, no information is available about the link between gene expression or concentration in the follicular microenvironment and oocyte development.What do the results of this study add? The study has shown that the relative Kisspeptin (KISS1) and Kisspeptin receptor (KISS1R) and expressions in cumulus cell (CC) and also KISS1 and KISS1R levels of follicle fluids (FF) were independent of oocytes nuclear and/or cytoplasmic maturation.What are the implications of these findings for clinical practice and/or further research? Based on the findings, it is difficult to establish a concept that kisspeptin can directly induce oocyte maturation. Nevertheless, to confirm these findings, further studies with a larger sample size are needed.

Impact of endometriosis on oocyte morphology in IVF-ICSI: retrospective study of a cohort of more than 6000 mature oocytes

BACKGROUND

Infertility associated with endometriosis can be explained by several non-exclusive mechanisms. The oocyte plays a crucial role in determining embryonic competence and this is particularly relevant for in vitro fertilization (IVF) outcomes. According to some authors, the morphology of oocytes could also be a non-invasive marker of oocyte quality. The aim of this study was to evaluate the relationship between endometriosis and oocyte morphology after controlled ovarian stimulation for intracytoplasmic sperm injection (ICSI) on a large oocyte cohort.

METHODS

Single-center comparative retrospective study in the academic In Vitro Fertilization (IVF) unit of the Lille University Hospital. A total of 596 women treated for IVF-ICSI with ejaculated spermatozoa for sperm alterations were included. They were classified as endometriosis (n = 175) or control groups (n = 401). The morphological evaluation of 2,016 mature oocytes from 348 cycles of patients with endometriosis was compared with that of 4,073 mature oocytes from 576 control cycles. The main outcome measures were Average Oocyte Quality Index (AOQI) and metaphase II oocyte morphological scoring system (MOMS). Comparison of groups was carried out by a mixed linear model and by a generalized estimation equation model with a "patient" random effect to consider that a patient might have several attempts.

RESULTS

No difference in AOQI and MOMS scores was found between endometriosis and control women (adjusted p = 0.084 and 0.053, respectively). In case of endometriosis, there were significantly fewer metaphase II oocytes retrieved, embryos obtained, grade 1 embryos and number of cumulative clinical pregnancies compared to controls. In the endometriosis group, endometriosis surgery was associated with a reduced number of mature oocytes retrieved, and the presence of endometrioma(s) was associated with some abnormal oocyte shapes. Nevertheless, no difference concerning the AOQI and MOMS scores was found in these subgroups.

CONCLUSION

Endometriosis does not have a negative impact on oocytes' morphology in IVF-ICSI.

TRIAL REGISTRATION

On December 16, 2019, the Institutional Review Board of the Lille University Hospital gave unrestricted approval for the anonymous use of all patients' clinical, hormonal and ultrasound records (reference DEC20150715-0002).

Oocyte Morphology and Reproductive Outcomes - Case Report and Literature Review

Oocyte quality could be negatively affected by many factors including smoking, alcohol consumption, obesity, woman's age, endometriosis and controlled ovarian stimulation (COS), during assisted reproductive technology (ART), in addition to genetic factors, such as hormone receptor polymorphisms, for example. We know that the increase in the reactive oxygen species (ROS) due to systemic disorders causes biochemical and morphological changes to the oocytes, interfering with their quality. The oocyte dysmorphism can be expressed through intra and/or extra cytoplasmic changes. In general, the size and number of oocytes' morphological abnormalities are directly related to preimplantation development failure. This case report is based on four in vitro fertilization (IVF) cycles performed by a patient with oocyte dysmorphism in all oocytes captured. The literature review on this topic aims to relate the characteristics of the oocytes, presented in the case report, with research results about the quality and morphology of the oocytes.

The rate of oocytes with granular cytoplasm is higher in women with endometrioma in ICSI cycles

The purpose of this study was to investigate the impact of endometrioma on oocyte morphology and fertility outcome in intracytoplasmic sperm injection (ICSI)cycles. The study material was obtained from 114 ICSI cycles of infertile women aged between 20 and 38 years with ovarian endometriomas and unexplained infertility. In total, 644 mature oocytes were included in the analysis. The rates of specific oocyte morphological abnormalities were similar between the two groups however the central granulation rate was significantly higher in the group with endometrioma (p < .05). Fertilisation rate were not significantly different between the groups (p ≥ .05) however the numbers of metaphase 2 (MII) oocytes and embryos were lower in the endometrioma group (p ≤ .05). Endometrioma was associated with a higher rate of oocytes with granular cytoplasm, despite the fertilisation rate the numbers of the MII oocytes and embryo were affected.IMPACT STATEMENTWhat is already known on this subject? The association between endometrioma and infertility is a well-known condition, but the possible mechanisms of the effects of endometrioma on women's fertility is still debated and controversial. There is limited data on the effect of endometrioma on oocyte morphology. Low oocyte quality and lower fertilisation rates might be the main cause of adverse pregnancy outcomes during in vitro fertilisation/intracytoplasmic sperm injection cycles.What do the results of this study add? Endometrioma was associated with a higher rate of oocytes with granular cytoplasm, and lower metaphase 2 oocytes and embryos.What are the implications of these findings for clinical practice and/or further research? Future studies using further oocyte quality assessment methods and prospective observational studies including live-birth rate should be designed to better understand how endometrioma affects fertility outcomes.

Endometriosis Lowers the Cumulative Live Birth Rates in IVF by Decreasing the Number of Embryos but Not Their Quality

Endometriosis and infertility are closely linked, but the underlying mechanisms are still poorly understood. This study aimed to evaluate the impact of endometriosis on in vitro fertilization (IVF) parameters, especially on embryo quality and IVF outcomes. A total of 1124 cycles with intracytoplasmic sperm injection were retrospectively evaluated, including 155 cycles with endometriosis and 969 cycles without endometriosis. Women with endometriosis had significantly lower ovarian reserve markers (AMH and AFC), regardless of previous ovarian surgery. Despite receiving significantly higher doses of exogenous gonadotropins, they had significantly fewer oocytes, mature oocytes, embryos, and top-quality embryos than women in the control group. Multivariate analysis did not reveal any association between endometriosis and the proportion of top-quality embryo (OR = 0.87; 95% CI [0.66-1.12]; p = 0.3). The implantation rate and the live birth rate per cycle were comparable between the two groups (p = 0.05), but the cumulative live births rate was significantly lower in in the endometriosis group (32.1% versus 50.7%, p = 0.001), as a consequence of the lower number of frozen embryos. In conclusion, endometriosis lowers the cumulative live birth rates by decreasing the number of embryos available to transfer, but not their quality.

Peritoneal fluid from women with endometriosis impairs human spermatozoa functionality

The success of mammalian fertilization depends largely on spermatozoa physiological events. However, the manner in which endometriosis influence morpho-functional spermatozoa biomarkers is poorly defined. Here, we studied in vitro the effect of peritoneal fluid (PF) from women with endometriosis (PFE) and non-endometriosis (PFNE) on spermatozoa parameters. This research was prospective and double-blind. A total of 45 PF samples were collected from women with (n = 25) and without endometriosis (n = 20). Semen samples were obtained from normozoospermic donors (n = 15) and cultured with 20 % (v/v) of PF or commercial culture medium (controls) during 0, 24, and 48 h. The outcome measures were spermatozoa/viability, motility, tyrosine phosphorylation (TP) and spontaneous acrosomal reaction. In addition, plasma membrane sugars were characterized by lectins [Aleuria aurantia agglutinin (AAA), Concanavalin A (ConA), Peanut agglutinin (PNA), and Wheat germ agglutinin (WGA)]. After a 24 -h culture, results reported a significant decrease in motility in cells cultured with PFE compared to the control, together with differences in the AAA and WGA-binding sites. Moreover, spermatozoa in contact with PFNE presented a significantly lower level of acrosome spontaneous reaction. At 48 h, no differences were observed in the biomarkers studied between the PFNE and the control, excluding ConA-binding sites. On the other hand, cells cultured with PFE exhibited significantly less motility, TP, and differences in the relocation of spermatozoa surface sugars. Viability was not affected in any culture condition. Overall, the effects of PFE could negatively affect spermatozoa quality, contributing to explain and diagnose the infertility associated to male partners of women with endometriosis.

Immunological microenvironment alterations in follicles of women with proven severe endometriosis undergoing in vitro fertilization

The purpose of this study was to test the hypothesis that different cytokine profiles may exist in the follicular fluid of endometriosis (EM) patients undergoing in vitro fertilization (IVF), as these differences may provide insights into the pathogenesis of the disease. This was a cross-sectional study conducted at the reproductive center of a medical university hospital. The study included 49 patients receiving IVF. 20 infertile women with proven EM and 29 women without diagnosed EM (control group) were evaluated. Follicular fluid (FF) and serum were collected at the time of follicle aspiration and the concentrations of 38 cytokines were determined by multiplexed immunoassay. The results indicated that the levels of IL-4, IL-13, IL-3 and IL-1α were significantly increased in the FF of women with EM, while levels of IFN-γ, IL-17A, MDC and MIP-1α were decreased compared with in the control subjects. In conclusions, the immune microenvironment of the FF in patients with EM is altered. This may contribute to the pathologic mechanism responsible for the poor outcome of IVF in patients with EM.

Mutation analysis of ZP1, ZP2, ZP3 and ZP4 genes in 152 Han Chinese samples with ovarian endometriosis

Endometriosis is characterized by the ectopic implant of endometrial tissue outside the uterine cavity and found in ˜35-50% of subfertile women. Previous studies have found that endometriosis had frequent defects in zona pellucida (ZP), and mutations in ZP genes could lead to ZP defects, raising the possibility that mutations in ZP genes might exist in endometriosis. We analyzed a total of 152 Han Chinese samples with ovarian endometriosis for the presence of mutations in the ZP1, ZP2, ZP3 and ZP4 genes. Two novel nonsynonymous ZP4 mutations were identified in three out of 152 (2.0%) samples: a p.M1?/(c.3 G > C) mutation in a 27- and 35-year-old sample, respectively, and a p.A433 V (c.1298C > T) mutation in a 31-year-old patient. No mutations were detected in ZP1, ZP2 or ZP3 genes; furthermore, no mutations in ZP genes were identified in 85 female control samples without endometriosis. The p.M1?/(c.3 G > C) mutation could lead to the usage of a downstream translation initiation site, while the evolutionary conservation and protein structural modeling analyses suggested that the p.A433 V mutation might be functionally important. However, there were strikingly different fertility outcomes among the three samples with ZP4 mutations: the p.A433V-mutated sample had no problem in fertility; while the p.M1?-mutated samples presented with paradoxical effects on fertility: the 35-year-old patient had a child while the 27-year-old patient was infertile, who underwent two spontaneous abortions and an implantation failure after IVF treatment. These results suggested that the potential role of ZP4 mutations on human fertility might be more complex than we thought, and other genetic and environment factors might play a role. In conclusion, we identified two novel mutations in the ZP4 gene in 2.0% of Han Chinese patients with ovarian endometriosis for the first time, our results suggested that mutations in ZP4, but not ZP1, ZP2 and ZP3, might play active roles in the pathogenesis of ovarian endometriosis, despite the mutation-carriers present with complex fertility outcomes.

What is the effect of embryo morphology on serum β-hCG levels?

OBJECTIVE

To determine the effect of embryonic factors on serum beta human chorionic gonadotropin (β-hCG) levels in pregnancy and live birth resulting after a single fresh cleavage embryo and blastocyst transfer.

STUDY DESIGN

This was a retrospective cohort study conducted at a tertiary care hospital. All fresh single embryo transfers (sETs) between September 2011 and December 2016 were included. The correlation analysis was performed to determine the association of embryo morphological parameters on mean serum β-hCG levels on day 12 after the transfer of a fresh single cleavage embryo and a fresh single blastocyst embryo.

RESULTS

Out of a total of 455 fresh sETs, 60 positive β-hCG results after the transfer of a single fresh cleavage-stage embryo and 82 after the transfer of a single fresh blastocyst. The mean β-hCG level resulting from a single fresh blastocyst ET was 371.7 ± 52.7 IU/L, which was similar to the mean β-hCG level resulting from a cleavage ET (314.5 ± 36.9 IU/L) (p = .70). Interestingly, serum β-hCG levels resulting from a single fresh blastocyst ET showed a correlation with day 5 blastocoele expansion, trophectoderm cell number and blastocyst quality score in ongoing pregnancy (r = .33, p = .02; r = .29, p = .04; and r = .31, p = .03, respectively). Moreover, day 5 blastocoele expansion and blastocyst quality score showed a correlation with the serum β-hCG levels resulting from a single fresh blastocyst ET in live birth (r = .36, p = .02; r = .31, p = .04, respectively).

CONCLUSION

Our study suggests that serum β-hCG levels resulting from a single fresh blastocyst ET showed a correlation with day 5 blastocoele expansion and blastocyst quality score in both ongoing pregnancy and live birth.