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

Impacts of type 1 diabetes mellitus on male fertility and embryo quality in superovulated mice

OBJECTIVE

We aimed to compare embryo quality, sperm morphology, motility, and fertilization obtained from male mice with type 1 diabetes mellitus (T1DM) induced by streptozotocin (STZ) in control and diabetic mice undergoing in vitro fertilization (IVF).

METHODS

CD-1 male mice were divided into control and DM groups, with an i.p. injection of 100 mg/kg STZ to induce T1DM. One month later, the mice were euthanized to investigate the effects of STZ-induced T1DM on the reproductive system. Sperms were obtained from the epididymis and vas deferens. The morphology and motility of the cells were evaluated. Follicle development was stimulated by controlled ovarian stimulation, and oocytes were collected by extracting oviducts and ovaries from female mice housed under controlled environmental conditions with ad libitum access. Both groups underwent IVF with fertilized zygotes followed up until the third day before embryo quality was compared.

RESULTS

Female mice bred with diabetic males exhibited significantly lower fertilization rates than the controls (p < 0.05). Sperm from diabetic mice displayed abnormalities in shape and movement, with reduced motility and fertilization. Embryos from male diabetic mice exhibited a higher incidence of developmental arrest during early embryogenesis. Although no significant differences in oocyte quality were observed, embryos from diabetic mice exhibited higher growth rates. These findings highlighted the T1DM's detrimental effects on sperm morphology, motility, fertilization, and early embryonic development, thus contributing to our understanding of reproductive complications.

CONCLUSION

In conclusion, our findings demonstrated that T1DM significantly impaired sperm morphology, motility, and fertilization capacity, leading to reduced embryo quality and increased developmental arrest. These results highlight the detrimental impact of DM on male reproductive potential and underscore the importance of glycemic control in optimizing outcomes in assisted reproductive techniques such as IVF.

Automated detection and recognition of oocyte toxicity by fusion of latent and observable features

Oocyte quality is essential for successful pregnancy, yet no discriminant criterion exists to assess the effects of environmental pollutants on oocyte abnormalities. We developed a stepwise framework integrating deep learning-extracted latent features with observable human-concept features focused on toxicity detection, subtype and strength classification. Based on 2126 murine oocyte images, this method achieves performance surpassing human capabilities with ROC-AUC of 0.9087 for toxicity detection, 0.7956-0.9034 for subtype classification with Perfluorohexanesulfonic Acid(PFHxS) achieving highest score of 0.9034 and 0.6434-0.9062 for toxicity strength classification with PFHxS achieving highest score of 0.9062. Notably, Ablation studies confirmed feature fusion improved performance by 18.7-23.4 % over single-domain models, highlighting their complementary relationship. Personalized heatmaps and feature importance revealed biomarker regions such as polar body and cortical areas aligning with clinical knowledge. AI-driven oocyte selection predicts embryo competence under pollutants, bridging computational toxicology to mitigate infertility.

A case report of a successful pregnancy after intracytoplasmic sperm injection when all oocytes contained abnormal inclusions in the perivitelline space

BACKGROUND

The relationship between oocyte morphology and developmental potential has been a hot research topic in assisted reproductive technology (ART). Whether inclusions in the perivitelline space (PVS) affect ART outcomes remains controversial.

CASE PRESENTATION

We present a case report of a 34-year-old G3P1A2 woman who sought ART treatment because of sequelae of pelvic disease. As her husband had severe oligospermia due to the stress on the day of oocyte retrieval, intracytoplasmic sperm injection (ICSI) was performed. After denudation, varying degrees of debris were found in the PVS, but all the oocytes were subjected to ICSI. Among the eleven retrieved oocytes, eight were fertilized. The morphology of the embryos was scored on Days 2 and 3. Five embryos were frozen on Day 3, and two best-quality embryos were subsequently transferred via frozen embryo transfer.

CONCLUSION

Severe debris in the PVS seems to affect embryo quality but not fertilization. Mild debris in the PVS may have little effect on the outcome of ART treatment. In our patient, after two embryos that were derived from oocytes with relatively few debris in the PVS were transferred, a successful live birth occurred.

Tauroursodeoxycholic Acid Enhances the Quality of Postovulatory Aged Oocytes by Alleviating Oxidative Stress, Apoptosis, and Endoplasmic Reticulum Stress in Pigs

One of the major factors causing reduced developmental capacity of aged porcine oocytes is the induction of oxidative stress during oocyte aging. Tauroursodeoxycholic acid (TUDCA) supports cellular function by acting as an antioxidant and free radical scavenger. The aim of this study is to evaluate whether exogenous supplementation of TUDCA to the porcine in vitro maturation system can ameliorate the compromised quality of aged oocytes by mitigating free radical production. We found that TUDCA was able to effectively maintain normal oocyte morphology, cortical granule distribution, and spindle structure during postovulatory aging. Additionally, the blastocyst rate and total cell number in blastocysts were significantly increased in aged porcine oocytes treated with TUDCA. Importantly, aged porcine oocytes treated with TUDCA reduced ROS levels, increased the expression levels of GSH and SOD1 genes, and improved the mitochondrial membrane potential ratio. Further study demonstrated that TUDCA significantly alleviated apoptosis in aged porcine oocytes, confirmed by the decreased Caspase 3 levels and ratio of BAX to BCL2. Interestingly, TUDCA could effectively alleviate the phenomenon of endoplasmic reticulum stress triggered during the oocyte aging process. Taking these findings together, our study demonstrates that TUDCA supplementation beneficially affects the quality of aged porcine oocytes by suppressing oxidative stress, apoptosis, and endoplasmic reticulum stress.

The embryological characteristics and clinical outcomes of oocytes with indented zona pellucida

BACKGROUND

Our study aimed to investigate the embryological characteristics and clinical outcomes of oocytes with indented zona pellucida (iZP).

METHODS

Cases with all oocytes containing iZP were compared with subjects whose oocytes presented morphologically normal ZP (nZP, controls), regarding embryological and clinical outcomes. Cases consisted of 56 subjects that underwent 109 assisted reproductive treatment (ART) cycles, and controls were made of 574 patients that were enrolled in 1095 ART cycles.

RESULTS

Patients with iZP presented a significantly prolonged duration of infertility and were more likely to have primary infertility. Regarding embryonic development, cases with iZP evidenced significantly lower rates of retrieved oocytes, oocyte maturity, fertilisation, embryo cleavage, high-quality embryo and blastocyst (p < .05). Relatively to clinical outcomes, 32 patients with iZP underwent fresh embryo transfer. Compared to controls, the rates of clinical pregnancy (CP) (43.8% vs. 65.9%, p = .014) and live-birth delivery (LBD) (34.4% vs. 58.5%, p = .009) were significantly lower. No significant differences were observed between groups regarding clinical outcomes after frozen-thawed embryo transfer (FET). However, cumulative rates elicited excellent CP (49.3%) and LBD (42.0%) rates in cases with iZP. In cases where rescue-intracytoplasmic sperm injection (ICSI) was needed, cases with iZP could achieve lower but nevertheless high cumulative CP (52.6%) and LBD (36.8%) rates.

CONCLUSIONS

Patients with iZP present satisfactory embryological and clinical outcomes, with ICSI and FET cycles improving the global outcomes.

Use of federated learning to develop an artificial intelligence model predicting usable blastocyst formation from pre-ICSI oocyte images

RESEARCH QUESTION

Can federated learning be used to develop an artificial intelligence (AI) model for evaluating oocyte competence using two-dimensional images of denuded oocytes in metaphase II prior to intracytoplasmic sperm injection (ICSI)?

RESULTS

The oocyte AI model demonstrated area under the curve (AUC) up to 0.65 on two blind test datasets. High sensitivity for predicting competent oocytes (83-88%) was offset by lower specificity (26-36%). Exclusion of confounding biological variables (male factor infertility and maternal age ≥35 years) improved AUC up to 14%, primarily due to increased specificity. AI score correlated with size of the zona pellucida and perivitelline space, and ooplasm appearance. AI score also correlated with blastocyst expansion grade and morphological quality. The sum of AI scores from oocytes in group culture images predicted the formation of two or more usable blastocysts (AUC 0.77).

CONCLUSION

An AI model to evaluate oocyte competence was developed using federated learning, representing an essential step in protecting patient data. The AI model was significantly predictive of oocyte competence, as defined by usable blastocyst formation, which is a critical factor for IVF success. Potential clinical utility ranges from selective oocyte fertilization to guiding treatment decisions regarding additional rounds of oocyte retrieval.

DESIGN

In total, 10,677 oocyte images with associated metadata were collected prospectively by eight IVF clinics across six countries. AI training used federated learning, where data were retained on regional servers to comply with data privacy laws. The final AI model required a single image as input to evaluate oocyte competence, which was defined by the formation of a usable blastocyst (≥expansion grade 3 by day 5 or 6 post ICSI).

Identification of a novel mutation in PATL2 gene associated with the germinal vesicle arrest of oocytes

The aim of this study was to investigate the genetic factors of a patient with germinal vesicle arrest in oocytes. Clinical data and blood samples were collected from the patient and some were amplified for high-throughput gene and Sanger sequencing. Several molecular and cellular experiments were performed to determine the association between the gene mutation and germinal vesicle arrest. Two mutation sites (c.1282G > T and c.1247C > A) were found in the PATL2 gene. The c.1282G > T mutation is associated with oocyte maturation abnormalities according to previous research, whereas c.1247C > A is a novel mutation of unknown clinical significance. In cell transfection experiments, qRT-PCR, immunofluorescence, and Western blotting revealed that the mRNA and protein levels of the PATL2 gene with the c.1247C > A mutation were reduced. Sanger sequencing suggested that the patient inherited the PATL2 mutations from her parents via a compound heterozygous mode of inheritance. Collectively, this study describes the PATL2-gene c.1247C > A mutation associated with germinal vesicle arrest in oocytes, providing a useful target for genetic and background tests for patients presenting with oocyte maturation abnormalities and/or germinal vesicle arrest following multiple unsuccessful attempts with assisted reproductive technology.

Quality of IVM ovarian tissue oocytes: impact of clinical, demographic, and laboratory factors

PURPOSE

To determine how clinical, demographic, and laboratory characteristics influence ovarian tissue oocyte quality.

METHODS

Immature cumulus-oocyte complexes were isolated from removed ovaries and cultured for 48-52 h in either monophasic standard or biphasic CAPA media for fertility preservation. A total of 355 MII oocytes from 53 patients were described for intracytoplasmic and extracytoplasmic anomalies. Multiple clinical, laboratory, and demographic characteristics were analyzed. Statistically significant differences between independent groups in qualitative variables were identified using Pearson's χ2 and Fisher's exact tests. The diagnostic value of quantitative variables was assessed using the ROC curve analysis. Factors associated with the development of dysmorphism, taking patient age into account, were identified using the binary logistic regression analysis.

RESULTS

Dysmorphisms were observed in 245 oocytes (69.0%), with a median number of dysmorphisms of 2. Oocyte dysmorphisms were found to be 2.211 times more likely to be detected in patients with ovarian cancer, while the presence of dark-colored cytoplasm was associated with gynecologic surgery in the anamnesis (p = 0.002; OR 16.652; 95% CI, 1.977-140.237; Cramer's V 0.187). Small polar bodies developed 2.717 times more often (95% CI, 1.195-6.18) in patients older than 35. In the case of ovarian transportation on ice at 4 ℃, the chances of development of cytoplasmic granularity increased 2.569 times (95% CI, 1.301-5.179). The use of biphasic CAPA IVM media contributed to a decrease in the probability of large polar body formation (p = 0.034) compared to the standard monophasic IVM media.

CONCLUSIONS

Both patients' characteristics and laboratory parameters have an impact on the quality of IVM ovarian tissue oocytes.

VPS34 Governs Oocyte Developmental Competence by Regulating Mito/Autophagy: A Novel Insight into the Significance of RAB7 Activity and Its Subcellular Location

Asynchronous nuclear and cytoplasmic maturation in human oocytes is believed to cause morphological anomalies after controlled ovarian hyperstimulation. Vacuolar protein sorting 34 (VPS34) is renowned for its pivotal role in regulating autophagy and endocytic trafficking. To investigate its impact on oocyte development, oocyte-specific knockout mice (ZcKO) are generated, and these mice are completely found infertile, with embryonic development halted at 2- to 4-cell stage. This infertility is related with a disruption on autophagic/mitophagic flux in ZcKO oocytes, leading to subsequent failure of zygotic genome activation (ZGA) in derived 2-cell embryos. The findings further elucidated the regulation of VPS34 on the activity and subcellular translocation of RAS-related GTP-binding protein 7 (RAB7), which is critical not only for the maturation of late endosomes and lysosomes, but also for initiating mitophagy via retrograde trafficking. VPS34 binds directly with RAB7 and facilitates its activity conversion through TBC1 domain family member 5 (TBC1D5). Consistent with the cytoplasmic vacuolation observed in ZcKO oocytes, defects in multiple vesicle trafficking systems are also identified in vacuolated human oocytes. Furthermore, activating VPS34 with corynoxin B (CB) treatment improved oocyte quality in aged mice. Hence, VPS34 activation may represent a novel approach to enhance oocyte quality in human artificial reproduction.

Summer versus winter: the impact of the seasons on oocyte quality in in vitro fertilization cycles

OBJECTIVE

The aim of this study was to determine the effects of seasons (winter vs. summer) on oocyte quality in infertile women undergoing ovulation induction for in vitro fertilization.

METHODS

This retrospective cross-sectional study assessed 155 cycles of in vitro fertilization-induced ovulation in women, with 71 and 84 cycles occurring in the summer and winter, respectively. Oocytes were evaluated for quality, with 788 and 713 assessed during summer and winter, and classified according to Nikiforov's categories: (a) category I, good quality; (b) category 2, medium quality; and (c) category 3, low quality.

RESULTS

Thickened zona pellucida (p<0.001), increased perivitelline space (p<0.001), oocyte shape abnormalities (p=0.01), and the presence of refractile bodies (p<0.0001) were more frequent in the summer cycles, whereas cytoplasmic granularity (p<0.001) was more frequent in the winter cycles. In winter, we observed a higher frequency of category 3 (p<0.001) and category 2 (p<0.001) oocytes and a lower frequency of category 1 (p<0.001) oocytes.

CONCLUSION

Oocyte dysmorphisms were found in 70-80% of cases and were more common in winter. The main features include a thickened zona pellucida, enlarged perivitelline space, irregular shape, and cytoplasmic granularity. This implies better-quality oocytes in the summer than in the winter. However, retrospective studies have limitations due to data collection biases and potential confounding variables such as diet and exercise. Future research is needed to confirm these findings and explore the underlying mechanisms.

Full-field optical coherence microscopy enables high-resolution label-free imaging of the dynamics of live mouse oocytes and early embryos

High quality label-free imaging of oocytes and early embryos is essential for accurate assessment of their developmental potential, a key element of assisted reproduction procedures. To achieve this goal, we propose full-field optical coherence microscopy (FF-OCM), constructed as a compact module fully integrated with a commercial wide-field fluorescence microscope. Our system achieves optical sectioning in wide-field, high in-plane resolution of 0.5 µm, and high sensitivity to backscattered light. To demonstrate its imaging capabilities, we study live mouse oocytes and embryos at all important stages of meiotic maturation and early embryogenesis. Our system enables visualization of intracellular structures, which are not visible in common bright-field microscopy, i.e., internal structure of nuclear apparatus, cytoskeletal filaments, cellular cortex, cytoplasmic protrusions, or zona pellucida features. Additionally, we visualize and quantify intracellular dynamics like cytoplasmic stirring motion, nuclear envelope fluctuations and nucleolus mobility. Altogether, we demonstrate that FF-OCM is a powerful tool for research in developmental biology that also holds great potential for non-invasive time-lapse monitoring of oocyte and embryo quality in assisted reproduction.

Ex ovo omnia-why don't we know more about egg quality via imaging?

Determining egg quality is the foremost challenge in assisted reproductive technology (ART). Although extensive advances have been made in multiple areas of ART over the last 40 years, oocyte quality assessment tools have not much evolved beyond standard morphological observation. The oocyte not only delivers half of the nuclear genetic material and all of the mitochondrial DNA to an embryo but also provides complete developmental support during embryonic growth. Oocyte mitochondrial numbers far exceed those of any somatic cell, yet little work has been done to evaluate the mitochondrial bioenergetics of an oocyte. Current standard oocyte assessment in in vitro fertilization (IVF) centers include the observation of oocytes and their surrounding cell complex (cumulus cells) via stereomicroscope or inverted microscope, which is largely primitive. Additional oocyte assessments include polar body grading and polarized light meiotic spindle imaging. However, the evidence regarding the aforementioned methods of oocyte quality assessment and IVF outcomes is contradictory and non-reproducible. High-resolution microscopy techniques have also been implemented in animal and human models with promising outcomes. The current era of oocyte imaging continues to evolve with discoveries in artificial intelligence models of oocyte morphology selection albeit at a slow rate. In this review, the past, current, and future oocyte imaging techniques will be examined with the goal of drawing attention to the gap which limits our ability to assess oocytes in real time. The implications of improved oocyte imaging techniques on patients undergoing IVF will be discussed as well as the need to develop point of care oocyte assessment testing in IVF labs.

Impact of oxygen tension during in vitro maturation: a sibling-oocyte prospective double-blinded study

OBJECTIVE

To determine whether oxygen (O2) tension (20% vs. 5%) has an impact on oocyte maturation rates and morphology during in vitro maturation (IVM).

DESIGN

A prospective, observational, monocentric, sibling-oocyte study.

SETTING

University Hospital.

PATIENTS

A total of 143 patients who underwent IVM for fertility preservation purposes from November 2016 to April 2021 were analyzed. Patients were included when ≥2 cumulus-oocyte complexes (COCs) were retrieved. The cohort of COCs obtained for each patient was randomly split into two groups: group 20% O2 and group 5% O2.

INTERVENTION

Cumulus-oocyte complexes were incubated for 48 hours either under 5% O2 or 20% O2. After 24 and 48 hours of culture, every oocyte was assessed for maturity and morphology, to estimate oocyte quality. Morphology was evaluated considering six parameters (shape, size, ooplasm, perivitelline space, zona pellucida, and polar body characteristics), giving a total oocyte score ranging from -6 to +6.

MAIN OUTCOME MEASURES

Maturation rates and total oocyte scores were compared using paired-sample analysis between group 20% O2 and group 5% O2.

RESULTS

Patient median age was 31.4 [28.1-35.2] years-old. The mean serum antimüllerian hormone levels and antral follicle count were 3.2 ± 2.3 ng/mL and 27.2 ± 16.0 follicles, respectively. A mean of 10.7 COCs per cycle were retrieved, leading to 6.1 ± 2.4 metaphase II oocytes vitrified (total maturation rate = 57.3%; 991 metaphase II oocytes/1,728 COCs). A total of 864 COCs were included in each group. Oocyte maturation rates were not different between the two groups (group 20% O2: 56.82% vs. group 5% O2: 57.87%, respectively). Regarding oocyte morphology, the mean total oocyte score was significantly higher in group 5% O2 compared with group 20% O2 (3.44 ± 1.26 vs. 3.16 ± 1.32, P=.014).

CONCLUSION

As culture under low O2 tension (5% O2) improves oocyte morphology IVM, our results suggest that culture under hypoxia should be standardized. Additional studies are warranted to assess the impact of O2 tension on oocyte maturation and the benefit of IVM under low O2 tension for embryo culture after utilization of frozen material.

Mature oocyte dysmorphisms may be associated with progesterone levels, mitochondrial DNA content, and vitality in luteal granulosa cells

PURPOSE

To identify whether follicular environment parameters are associated with mature oocyte quality, embryological and clinical outcomes.

METHODS

This retrospective study examined 303 mature oocytes from 51 infertile women undergoing ICSI cycles between May 2018 and June 2021. Exclusion criteria consisted of advanced maternal age (> 36 years old), premature ovarian failure, obesity in women, or use of frozen gametes. Luteal granulosa cells (LGCs) were analyzed for mitochondrial DNA/genomic (g) DNA ratio and vitality. The relationships between hormone levels in the follicular fluid and oocyte features were assessed. Quantitative morphometric measurements of mature oocytes were assessed, and the association of LGC parameters and oocyte features on live birth rate after single embryo transfer was examined.

RESULTS

Results indicated an inverse correlation between the mtDNA/gDNA ratio of LGCs and the size of polar body I (PBI). A 4.0% decrease in PBI size was observed with each one-unit increase in the ratio (p = 0.04). Furthermore, a 1% increase in LGC vitality was linked to a 1.3% decrease in fragmented PBI (p = 0.03), and a 1 ng/mL increase in progesterone levels was associated with a 0.1% rise in oocytes with small inclusions (p = 0.015). Associations were drawn among LGC characteristics, perivitelline space (PVS) debris, cytoplasmic inclusions, PBI integrity, and progesterone levels. Certain dysmorphisms in mature oocytes were associated with embryo morphokinetics; however, live birth rates were not associated with follicular parameters and oocyte quality characteristics.

CONCLUSION

Follicular markers may be associated with mature oocyte quality features.

How great thou ART: biomechanical properties of oocytes and embryos as indicators of quality in assisted reproductive technologies

Assisted Reproductive Technologies (ART) have revolutionized infertility treatment and animal breeding, but their success largely depends on selecting high-quality oocytes for fertilization and embryos for transfer. During preimplantation development, embryos undergo complex morphogenetic processes, such as compaction and cavitation, driven by cellular forces dependent on cytoskeletal dynamics and cell-cell interactions. These processes are pivotal in dictating an embryo's capacity to implant and progress to full-term development. Hence, a comprehensive grasp of the biomechanical attributes characterizing healthy oocytes and embryos is essential for selecting those with higher developmental potential. Various noninvasive techniques have emerged as valuable tools for assessing biomechanical properties without disturbing the oocyte or embryo physiological state, including morphokinetics, analysis of cytoplasmic movement velocity, or quantification of cortical tension and elasticity using microaspiration. By shedding light on the cytoskeletal processes involved in chromosome segregation, cytokinesis, cellular trafficking, and cell adhesion, underlying oogenesis, and embryonic development, this review explores the significance of embryo biomechanics in ART and its potential implications for improving clinical IVF outcomes, offering valuable insights and research directions to enhance oocyte and embryo selection procedures.

Embryological characteristics and clinical outcomes of oocytes with different degrees of abnormal zona pellucida during assisted reproductive treatment

Abnormalities in the zona pellucida (ZP) adversely affect oocyte maturation, embryo development and pregnancy outcomes. However, the assessment of severity is challenging. To evaluate the effects of different degrees of ZP abnormalities on embryo development and clinical outcomes, in total, 590 retrieval cycles were scored and divided into four categories (control, mild, moderate and severe) based on three parameters: perivitelline space, percentage of immature oocytes and percentage of oocytes with abnormal morphology. As the severity of abnormal ZP increased, both the number of retrieved oocytes and mature oocytes decreased. The fertilization rate did not differ significantly among groups. The rates of embryo cleavage and day-3 high-quality embryos in the mild group and the moderate group did not vary significantly between the two groups but were significantly higher than those in the severe group. The blastulation rates of the abnormal ZP groups were similar; however, they were lower than those of the control group. Moreover, the cycle cancellation rate of the severe abnormal ZP group was as high as 66.20%, which was significantly higher than that of the other three groups. Although the rates of cumulative clinical pregnancy and live births were lower than those in the control group, they were comparable among the abnormal ZP groups. There were no differences in the neonatal outcomes of the different groups. Together, ZP abnormalities show various degrees of severity, and in all patients regardless of the degree of ZP abnormalities who achieve available embryos, there will be an opportunity to eventually give birth.

Expression of mitochondrial transcription factor A in granulosa cells: implications for oocyte maturation and in vitro fertilization outcomes

OBJECTIVE

In vitro fertilization-embryo transfer (IVF-ET) is a widely used treatment for infertility, with oocyte maturation and quality having a significant impact on oocyte fertilization, embryo development, and fetal growth. Mitochondrial transcription factor A (TFAM) is essential for maintaining the mitochondrial oxidative respiratory chain and supplying energy for oocyte development, fertilization, and embryonic development. In this study, we aimed to examine TFAM expression in women undergoing IVF-ET and assess its impact on the IVF outcomes.

METHODS

We recruited 85 women who underwent IVF-ET treatment for infertility. On the date of egg collection, granulosa cells were extracted from the clear follicular fluid of the first mature egg using ultrasound-guided needle aspiration. The collected granulosa cells served three purposes: (1) detecting TFAM gene expression in granulosa cells via immunocytochemistry, (2) determining TFAM mRNA expression using reverse transcription-PCR (RT-PCR), and (3) measuring TFAM protein expression through western blotting.

RESULT

Based on the results, we found that TFAM was localized and expressed in the cytoplasm of granulosa cells, whereas no expression was detected in the nucleus. Granulosa cells exhibited a linear correlation between TFAM mRNA and TFAM protein expression. The study participants were divided into three groups using the ternary method based on relative TFAM mRNA expression thresholds of 33% and 76%: the low-expression group (n = 30), the moderate-expression group (n = 27), and the high-expression group (n = 28). When compared to the other two groups, the moderate expression group exhibited a significantly higher egg utilization rate, 2 pronucleus rate, fertilization rate, and clinical pregnancy rate (P < 0.05).

CONCLUSION

TFAM was detected in the cytoplasm of human ovarian granulosa cells. Women with moderate TFAM expression demonstrate enhanced outcomes in IVF.

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.

Chromatin Configuration in Diplotene Mouse and Human Oocytes during the Period of Transcriptional Activity Extinction

In the oocyte nucleus, called the germinal vesicle (GV) at the prolonged diplotene stage of the meiotic prophase, chromatin undergoes a global rearrangement, which is often accompanied by the cessation of its transcriptional activity. In many mammals, including mice and humans, chromatin condenses around a special nuclear organelle called the atypical nucleolus or formerly nucleolus-like body. Chromatin configuration is an important indicator of the quality of GV oocytes and largely predicts their ability to resume meiosis and successful embryonic development. In mice, GV oocytes are traditionally divided into the NSN (non-surrounded nucleolus) and SN (surrounded nucleolus) based on the specific chromatin configuration. The NSN-SN transition is a key event in mouse oogenesis and the main prerequisite for the normal development of the embryo. As for humans, there is no single nomenclature for the chromatin configuration at the GV stage. This often leads to discrepancies and misunderstandings, the overcoming of which should expand the scope of the application of mouse oocytes as a model for developing new methods for assessing and improving the quality of human oocytes. As a first approximation and with a certain proviso, the mouse NSN/SN classification can be used for the primary characterization of human GV oocytes. The task of this review is to analyze and discuss the existing classifications of chromatin configuration in mouse and human GV oocytes with an emphasis on transcriptional activity extinction at the end of oocyte growth.

Evaluation of Intrafollicular Syndecan 1, Glypican 3, and Spermidine Levels in Women with Diminished Ovarian Reserve

We aimed to evaluate the levels of Spermidine, Syndecan 1, and Glypican 3 (GPC3) in the follicle fluid of women with diminished ovarian reserve (DOR) and to examine the relationship of these markers with the number of embryos and clinical pregnancy. A total of 27 women with DOR and 34 women with normal ovarian reserve who underwent in vitro fertilization procedure were included in this prospectively designed study. Spermidine, Syndecan 1, and GPC3 levels were studied in the follicle fluid samples taken from the women at the time of oocyte retrieval by ELISA method, and their relations with the cycle outcomes were examined. The mean age was found as 38.1 ± 7.4 years in the DOR group and 35.1 ± 5.2 years in the control group (p = 0.027). When adjusted for age and body mass index, while the median Spermidine level was significantly higher (p < 0.001), both Syndecan 1 (p < 0.001) and GPC3 (p = 0.006) were significantly lower in the DOR group compared with control group. The cut-off value of Spermidine for clinical pregnancy prediction was found as 74.08 ng/mL with 78.9% sensitivity and 57.1% specificity [OR: 5 (95% CI: 1.4-17.6); AUC: 0.621; p = 0.138], while it was 0.96 ng/mL with 84.2% sensitivity and 59.5% specificity [OR: 7.8 (95% CI: 2-31.1); AUC: 0.701; p = 0.004] for GP3 and 1.15 ng/mL with 78.9 sensitivity and 57.1% specificity [OR: 5 (95% CI: 1.4-17.6); AUC: 0.680; p = 0.009] for Syndecan 1. Intrafollicular spermidine, Syndecan 1, and GPC3 levels may have a role in ovarian aging. Further randomized controlled studies in a larger population are needed for the relationship of these markers with cycle and pregnancy outcomes.

Can successful pregnancy be achieved and predicted from patients with identified ZP mutations? A literature review

BACKGROUND

In mammals, normal fertilization depends on the structural and functional integrity of the zona pellucida (ZP), which is an extracellular matrix surrounding oocytes. Mutations in ZP may affect oogenesis, fertilization and early embryonic development, which may cause female infertility.

METHODS

A PubMed literature search using the keywords 'zona pellucida', 'mutation' and 'variant' limited to humans was performed, with the last research on June 30, 2022. The mutation types, clinical phenotypes and pregnancy outcomes were summarized and analyzed. The naive Bayes classifier was used to predict clinical pregnancy outcomes for patients with ZP mutations.

RESULTS

A total of 29 publications were included in the final analysis. Sixty-nine mutations of the ZP genes were reported in 87 patients with different clinical phenotypes, including empty follicle syndrome (EFS), ZP-free oocytes (ZFO), ZP-thin oocytes (ZTO), degenerated and immature oocytes. The phenotypes of patients were influenced by the types and location of the mutations. The most common effects of ZP mutations are protein truncation and dysfunction. Three patients with ZP1 mutations, two with ZP2 mutations, and three with ZP4 mutations had successful pregnancies through Intracytoplasmic sperm injection (ICSI) from ZFO or ZTO. A prediction model of pregnancy outcome in patients with ZP mutation was constructed to assess the chance of pregnancy with the area under the curve (AUC) of 0.898. The normalized confusion matrix showed the true positive rate was 1.00 and the true negative rate was 0.38.

CONCLUSION

Phenotypes in patients with ZP mutations might be associated with mutation sites or the degree of protein dysfunction. Successful pregnancy outcomes could be achieved in some patients with identified ZP mutations. Clinical pregnancy prediction model based on ZP mutations and clinical characteristics will be helpful to precisely evaluate pregnancy chance and provide references and guidance for the clinical treatment of relevant patients.

The Future Is Coming: Artificial Intelligence in the Treatment of Infertility Could Improve Assisted Reproduction Outcomes-The Value of Regulatory Frameworks

Infertility is a global health issue affecting women and men of reproductive age with increasing incidence worldwide, in part due to greater awareness and better diagnosis. Assisted reproduction technologies (ART) are considered the ultimate step in the treatment of infertility. Recently, artificial intelligence (AI) has been progressively used in the many fields of medicine, integrating knowledge and computer science through machine learning algorithms. AI has the potential to improve infertility diagnosis and ART outcomes estimated as pregnancy and/or live birth rate, especially with recurrent ART failure. A broad-ranging review has been conducted, focusing on clinical AI applications up until September 2022, which could be estimated in terms of possible applications, such as ultrasound monitoring of folliculogenesis, endometrial receptivity, embryo selection based on quality and viability, and prediction of post implantation embryo development, in order to eliminate potential contributing risk factors. Oocyte morphology assessment is highly relevant in terms of successful fertilization rate, as well as during oocyte freezing for fertility preservation, and substantially valuable in oocyte donation cycles. AI has great implications in the assessment of male infertility, with computerised semen analysis systems already in use and a broad spectrum of possible AI-based applications in environmental and lifestyle evaluation to predict semen quality. In addition, considerable progress has been made in terms of harnessing AI in cases of idiopathic infertility, to improve the stratification of infertile/fertile couples based on their biological and clinical signatures. With AI as a very powerful tool of the future, our review is meant to summarise current AI applications and investigations in contemporary reproduction medicine, mainly focusing on the nonsurgical aspects of it; in addition, the authors have briefly explored the frames of reference and guiding principles for the definition and implementation of legal, regulatory, and ethical standards for AI in healthcare.

The association between serum sex hormone-binding globulin changes during progestin-primed ovarian stimulation and embryo outcomes: a retrospective cohort study

Objective: This study is aimed to examine the associations between embryo outcomes and serum sex hormone-binding globulin (SHBG) changes during progestin-primed ovarian stimulation (PPOS) protocols in IVF/ICSI cycles.Research methods: This study included 2790 eligible consecutive cycles of patients aged 21-53 years undergoing PPOS treatment. Multivariable linear regression analysis was performed to explore the association between SHBG changes and embryo outcomes.Results of the study: Our results showed that the SHBG-increase rate on the HCG day and in the late follicular phase were positively and linearly correlated with available embryos in day3, with adjusted regression coefficients (β) for the SHBG-increase rate on the HCG day, in the late follicular phase were 0.6 (0.4, 0.9), 0.4 (0.2, 0.6), but in the middle follicular phase and in the early follicular phase, this correlation was not significant (p > 0.05).Conclusion: Our results indicate that serum SHBG increment may serve as a biomarker of the developmental potential of the oocytes from patients undergoing the PPOS protocol.