CUMULUS CELL GENES AS POTENTIAL BIOMARKERS OF OOCYTE AND EMBRYO DEVELOPMENTAL COMPETENCE

The effect of Myo-Inositol supplement on molecular regulation of folliculogenesis, steroidogenesis, and assisted reproductive technique outcomes in patients with polycystic ovarian syndrome

RESEARCH QUESTION

The mechanism of Myo-Inositol, as an adjuvant, on key signaling pathways related to oocyte maturation, fertilization rate, and embryo quality as well as ovarian steroidogenesis in cumulus cells of PCOS patients, is still unclear.

DESIGN

Infertile patients who were candidates for ART cycles were divided into three groups (n = 30 in each group), including group 1: PCOS patients only receiving folic acid, group 2: PCOS patients receiving daily Myo-Inositol combined with folic acid, and a control group (group 3): normal ovulatory women without PCOS receiving only folic acid from 1 month prior to IVF cycle until the day of ovum pick up. During the ART procedure, oocytes maturation, fertilization rate, and embryo quality were assessed. The gene expressions of FSHR, LHR, CYP11A1, CYP19A1, 3β-HSD2, and StAR were also analyzed using qRT-PCR. Western blot analysis was performed for the evaluation of AKT, ERK, CREB, and AMPK phosphorylation.

RESULT

Despite equal number of retrieved oocytes, the percentages of MII oocytes, fertilization rate, and embryo quality were found to be significantly higher in group 2 due to the administration of inofolic. The expressions of all the studied genes were significantly higher in the cumulus cells of group 1 compared to the group 2. Higher phosphorylation of ERK1/2 was found in the groups 2 and 3 compared to the group 1. On the other hand, p-Akt has significantly decreased in the group 2 compared to the group 1.

CONCLUSION

Our study provides new insight into the molecular mechanism underlying the positive effect of Myo-Inositol on intrinsic ovarian defects in PCOS, steroidogenesis, oocyte maturation, fertilization rate, and embryo quality.

Improved clinical outcomes after non-invasive oocyte selection and Day 3 eSET in ICSI patients

BACKGROUND

Non-invasive oocyte quality scoring, based on cumulus gene expression analysis, in combination with morphology scoring, can increase the clinical pregnancy (CPR) and live birth rates (LBR) in Day 3 eSET (elective single embryo transfer) ICSI patients. This was first investigated in a pilot study and is now confirmed in a large patient cohort of 633 patients. It was investigated whether CPR, LBR and time-to-pregnancy could be improved by analyzing the gene expression profile of three predictive genes in the cumulus cells, compared to patients with morphology-based embryo selection only.

METHODS

A large interventional, non-randomized, assessor-blinded cohort study with 633 ICSI patients was conducted in a tertiary fertility center. Non-PCOS patients, 22-39 years old, with good ovarian reserve, were stimulated with HP-hMG using a GnRH antagonist protocol and planned for fresh Day 3 eSET. The cumulus cells from individually denuded oocytes were ranked by a lab-developed cumulus cell test: qRT-PCR for three predictive genes (CAMK1D, EFNB2 and SASH1) and two control genes (UBC, B2M). The embryo selected for transfer was highest ranked from the pool of morphologically transferable Day 3 embryos. Patients in the control (n = 520) and experimental arm (n = 113) were compared for clinical pregnancy and live birth, using a weighted generalized linear model, and time-to-pregnancy using Kaplan-Meier curves.

RESULTS

The CPR was 61% in the experimental arm (n = 113) vs 29% in the control arm (n = 520, p < 0.0001). The LBR in the experimental arm (50%) was significantly higher than in the control arm (27%,p < 0.0001). Time-to-pregnancy was significantly shortened by 3 transfer cycles independent of the number of embryos available on Day 3 (Kaplan-Meier, p < 0.0001). Cumulus cell tested patients < 35 years (n = 65) or ≥ 35 years (n = 48) had a CPR of 62 and 60% respectively (ns). For cumulus cell tested patients with 2, 3-4, or > 4 transferable embryos, the CPR was 66, 52, and 67% (ns) respectively, and thus independent of the number of transferable embryos on Day 3.

CONCLUSIONS

This study provides further evidence of the clinical usefulness of the non-invasive cumulus cell test over time in a larger patient cohort.

TRIAL REGISTRATION

Clinicaltrials.gov, NCT03659786 / NCT02962466 (Registered 6Sep2018/11Nov2016, retrospectively registered.

Oxidative stress markers in the follicular fluid of patients with polycystic ovary syndrome correlate with a decrease in embryo quality

PURPOSE

Elevated oxidative stress has been proposed as an important factor in the pathogenesis of polycystic ovary syndrome (PCOS)-related infertility. Our study was aimed at simultaneously exploring local and systemic oxidative stress in PCOS individuals and its relationship with embryo quality.

METHODS

We recruited 86 PCOS cases and 60 controls. Five representative oxidative stress markers, namely, total oxidant capacity (TOC), total antioxidant capacity (TAC), malonaldehyde (MDA), glutathione (GSH), and superoxide dismutase (SOD), were measured in both follicular fluid (FF) and serum.

RESULTS

Women with PCOS compared to normal controls had higher levels of TOC in both FF (10.13 ± 2.68 vs.7.03 ± 2.45, P < 0.001) and serum (11.76 ± 2.92 vs. 8.82 ± 2.57, P < 0.001). The oxidative stress index (OSI, the ratio of TOC to TAC) was also higher in PCOS cases. They were still significant after BMI adjustment (Padj<0.01). In addition, the serum OSI level was much higher than the FF OSI level in both groups. Correlation analysis showed that the FF and serum TOC were negatively correlated with the high-quality embryo rate on day 3 and the later blastocyst formation rate in the PCOS group (P < 0.05). The correlation coefficient was higher in FF. Moreover, as the regression analysis data showed, the FF MDA level was significantly associated with embryo quality indicators (P < 0.05).

CONCLUSIONS

PCOS was accompanied by elevated oxidative stress in both serum and FF. Even though serum oxidative stress was severe, the study suggested that FF oxidative stress contributed more to embryo quality, to which we should give more attention in the future.

HAS2-AS1 is a novel LH/hCG target gene regulating HAS2 expression and enhancing cumulus cells migration

Background

The cumulus expansion process is one of the LH mediated ovulatory processes. Hyaluronan synthase 2 (HAS2) regulates the synthesis of hyaluronic acid, the main component of the cumulus expansion process. Recently, the lncRNA HAS2 antisense RNA 1 (HAS2-AS1) was identified in our global transcriptome RNA-sequencing of novel ovulation associated genes. The role of HAS2-AS1 in HAS2 regulation w.as studied previously with contradictive results in different models but not in the ovary. Taken together the induction of HAS2-AS1 and the important role of HAS2 in the cumulus expansion process, we hypothesize that HAS2-AS1 regulate HAS2 expression and function in the ovary. Therefore we undertook to study the expression, regulation, and possible functional role of HAS2-AS1 in the human ovary.

Results

HAS2-AS1, located within the HAS2 gene that was highly regulated in our library. We found that HAS2-AS1 express mainly in cumulus cells (CCs). Furthermore, HAS2-AS1 showed low expression in immature CCs and a significant increase expression in mature CCs. Functional studies reveal that inhibition of HAS2-AS1 by siRNA caused decrease expression of HAS2. Furthermore, inhibition of HAS2-AS1 by siRNA results in decrease migration of granulosa cells.

Conclusions

Our results suggest that HAS2-AS1 is an LH/hCG target gene that plays a positive role in HAS2 expression and thus might play a role in regulating cumulus expansion and migration.

Changes in DNA integrity and gene expression in ovarian follicular cells of lipopolysaccharide-treated female mice

BACKGROUND

Lipopolysaccharide (LPS), the endotoxin of gram-negative bacteria, can impair female reproductive function. However, there is a little information about genotoxic stress in ovarian follicular cells as well as about the changes in oocyte developmental potential under endotoxemia. So the aim of our study was to investigate in vitro oocyte maturation, the DNA damage and expression of some developmental competence-related genes in follicular cells of mice treated with LPS.

METHODS

LPS (3mg/kg) was intraperitoneally injected into the mice for 24h, and in vitro maturation of mouse oocyte was determined. The expression levels of genes in cumulus cells were detected by reverse transcriptase polymerase chain reaction. DNA damage in granulosa cells was assessed by the alkaline comet assay.

RESULTS

LPS injection caused an impairment of oocyte maturation in vitro: the percentage of oocytes reaching metaphase I and metaphase II decreased markedly compared to vehicle control mice. At the same time we observed strong DNA damage in granulosa cells of LPS-treated animals. The endotoxemia resulted in significantly reduced mRNA expression levels for hyaluronan synthase 2 (HAS2), cyclooxygenase 2 (COX2) and Gremlin-1 (GREM1) genes compared with control.

CONCLUSIONS

Our results obtained in a mouse model of endotoxin-induced female reproductive dysfunction suggest that LPS may affect oocyte quality through the induction of DNA damage and decreasing the cumulus expression of genes associated with cumulus expansion and oocyte maturation, such as HAS2, COX2 and GREM1.