Role of epigenetic modifications in the aberrant CYP19A1 gene expression in polycystic ovary syndrome

INTRODUCTION

In this study, the global DNA methylation, histone acetylation and methylation levels of cumulus cells (CCs) in infertile polycystic ovary syndrome (PCOS) patients and the correlation of these epigenetic modifications with the expression of the ovarian aromatase gene (as an important marker in the etiology of PCOS) were investigated.

MATERIAL AND METHODS

A cross-sectional study was conducted on 24 patients (12 PCOS patients and 12 healthy women), who underwent ovarian stimulation. Nucleosome ELISA was performed, in order to identify the global occupancy level of Mecp2 (as a marker of DNA methylation) and H3K9me2/H3K9ac as histone modification markers in chromatin fractions obtained from CCs. The CYP19A1 gene expression was measured by qRT-PCR. The level of DNA incorporation of MeCP2, histone modification markers and binding of estrogen receptor β (ERβ) to CYP19A1 regulatory sequences were examined by ChIP-QPCR assay.

RESULTS

The data demonstrate a significant increase in global occupancy levels of MeCP2 and H3K9ac markers and a decrease of H3K9me2 to chromatin in CCs of PCOS patients vs. control group. Furthermore, CYP19A1 gene expression, and the incorporation of H3K9ac in PII, PI.3, and PI.4 promoters of CYP19A1 in PCOS, were higher than those of controls. Also, significant hypomethylation of H3K9 at PII and DNA hypomethylated at PII and PI.3 promoters and differential binding of ERβ to three promoters were observed in PCOS patients (p < 0.05).

CONCLUSIONS

Aromatase expression can be affected by epigenetic modifications and differential ERβ binding to the proximal CYP19A1 promoters. These mechanisms may be involved in the enhanced aromatase transcription during ovarian stimulation in PCOS patients.

Total Antioxidant Capacity; A Potential Biomarker for Non-Invasive Sex Prediction in Culture Medium of Preimplantation Human Embryos

Objective

The presence of a sex related metabolic difference in glucose utilization and, on the other hand, different developmental kinetic rates in human preimplantation embryos, has been previously observed, hawever, the correlation between these two events is unknown. Oxidative stress (OS) induced by higher glucose consumption appears to be a possible cause for the delayed development rate in female embryos. We examined the correlation between glucose consumption and total antioxidant capacity (TAC) concentration in individual embryo culture media for both male and female embryos.

Materials and Methods

In this cross-sectional study, we evaluated high quality embryos from 51 patients that underwent intracytoplasmic sperm injection (ICSI) and preimplantation genetic diagnosis (PGD) at the Royan Institute between December 2014 and September 2017. The embryos were individually cultured in G-2TMmedium droplets at days 3-5 or 48 hours post PGD. We analysed the spent culture media following embryo transfer for total antioxidant capacity (TAC) and any remaining glucose concentrations through fluorometric measurement by chemiluminecence system which indirectly was used for measurement of glucose consumed by embryos.

Results

The results showed that female embryos consumed more glucose which was associated with decreased TAC concentration in their culture medium compared to male embryos. The mean of glucose concentration consumed by the female embryos (30.7 ± 4.7 pmol/embryo/hour) was significantly higher than that of the male embryos (25.3 ± 3.3 pmol/embryo/hour) (P<0.001). There were significantly lower levels of TAC in the surrounding culture medium of female embryos (22.60 ± 0.19 nmol/µl) compared with male embryos (24.74 ± 0.27 nmol/µl, P<0.01).

Conclusion

This finding highlighted the utilization of sex dependent metabolic diversity between preimplantation embryos for non-invasive sex diagnosis and suggests the TAC concentration as a potential noninvasive biomarker for prediction of sex.

Oxidative Stress Statues in Serum and Follicular Fluid of Women with Endometriosis

OBJECTIVE

This study aimed to evaluate the levels of two oxidative stress (OS) markers including lipid peroxide (LPO) and total antioxidant capacity (TAC) in both serum and follicular fluid (FF) of women with endometriosis after puncture.

MATERIALS AND METHODS

In this cross-sectional study, a total number of sixty-three women younger than 40 years old with laparoscopy (gold standard for endometriosis diagnosis) indication underwent in vitro fertilization (IVF) program in the Royan Institute, Tehran, Iran from September 2013 to October 2014. About forty-three patients were diagnosed with endometriosis after laparoscopy. Blood and FF from the leading follicle in each stimulated ovary were obtained at the time of egg retrieval; samples were centrifuged and frozen until assessment. At the time of sample assessment, serum and FF samples were evaluated for the levels of LPO and TAC on spectrophotometery.

RESULTS

We observed that women with endometriosis had significantly higher LPO and lower TAC levels in the serum and FF as compared with the control group (P<0.05).

CONCLUSION

It has observed that FF of women with endometriosis, regardless of disease stage, increases the proliferation power of endometrial cells in vitro, we presume that inflammatory reactions-induced OS in ovary may be responsible for proliferation induction ability in FF obtained from women with endometriosis.

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.

Zygote intrafallopian tube transfer versus intrauterine cleavage or blastocyst stage transfer after intracytoplasmic sperm injection cycles in patients with repeated implantation failure: A prospective follow-up study

AIM

This study aimed to compare the outcomes between zygote intrafallopian transfer (ZIFT) with intrauterine day-3 (cleavage stage) embryo transfer and intrauterine day-5 (blastocyst stage) embryo transfer in patients undergoing intracytoplasmic sperm injection.

MATERIAL AND METHODS

This prospective study was performed at Royan Institute, Tehran, Iran, between January 2012 and January 2014. Two hundred fifty women with more than three unexplained implantation failures were divided non-randomly into three groups according to embryonic age and methods used as follows: (i) intrauterine cleavage-stage embryo transfer (n = 100); (ii) intrauterine blastocyst-stage embryo transfer (n = 50); and (iii) ZIFT (n = 100). Implantation, clinical pregnancy, miscarriage and live birth rates were our main outcomes.

RESULTS

Patients' characteristics and ovarian response were comparable among the three groups. Implantation rate (56.1% vs 27.9%) was significantly higher in the blastocyst group as compared to the ZIFT group; however, clinical pregnancy rate (38% vs 23%) was not statistically significantly different between the two groups, but due to the significantly higher miscarriage rate (34.7% vs 5.3%) in the ZIFT group, the live birth rate was significantly higher in the blastocyst group (P = 0.04). No significant differences were found between the cleavage-stage and blastocyst-stage groups in terms of implantation, clinical pregnancy, miscarriage and live birth rates.

CONCLUSION

We do not recommend the use of the ZIFT procedure for patients with repeated implantation failures. It seems that replication of cleavage- or blastocyst-stage embryo transfer is more efficient and affordable.

The Effects of ISM1 Medium on Embryo Quality and Outcomes of IVF/ICSI Cycles

BACKGROUND

The aim of this study is to investigate the effect of ISM1 culture medium on embryo development, quality and outcomes of in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) cycles. This study compares culture medium commonly used in the laboratory setting for oocyte recovery and embryo development with a medium from MediCult. We have assessed the effects of these media on embryo development and newborn characteristics.

MATERIALS AND METHODS

In this prospective randomized study, fertilized oocytes from patients were randomly assigned to culture in ISM1 (MediCult, cycles: n=293) or routine lab culture medium (G-1TM v5; Vitrolife, cycles: n=290) according to the daily media schedule for oocyte retrieval. IVF or ICSI and embryo transfer were performed with either MediCult media or routine lab media. Embryo quality on days 2/3, cleavage, pregnancy and implantation rates, baby take home rate (BTHR), in addition to the weight and length of newborns were compared between groups.

RESULTS

There were similar cleavage rates for ISM1 (86%) vs. G-1TM v5 (88%). We observed a significantly higher percentage of excellent embryos in ISM1 (42.7%) compared to G-1TM v5 (39%, p<0.05). Babies born after culture in ISM1 had both higher birth weight (3.03 kg) and length (48.8 cm) compared to G-1TM v5 babies that had a birth weight of 2.66 kg and a length of 46.0 cm (p<0.001 for both).

CONCLUSION

This study suggests that ISM1 is a more effective culture medium in generating higher quality embryos, which may be reflected in the characteristics of babies at birth.

Relationship of seminal reactive nitrogen and oxygen species and total antioxidant capacity with sperm DNA fragmentation in infertile couples with normal and abnormal sperm parameters

The objective of this study was to investigate the association between the amount of superoxide anion, peroxynitrite as oxidative stress (OS) markers and total antioxidant capacity (TAC) with sperm DNA fragmentation in infertile men with abnormal semen parameters. Semen samples were obtained from 102 infertile couples and divided into groups with normal and abnormal semen parameters according to the World Health Organization (WHO). Peroxynitrite and superoxide anions were detected using spectrofluorometric assays combined with 2,7 dicholorofluorescein (DCF)-DA and 4-chloro-7-nitrobenzo-2-oxa -1, 3-diazole (NBD-CL). Colorimetric assay was used for evaluation of TAC, while DNA fragmentation was studied by using sperm chromatin dispersion test. Superoxide anion, peroxynitrite and DNA fragmentation were significantly higher in infertile couples with abnormal semen parameters as compared to infertile couples with normal semen (P < 0.01). TAC was significantly lower in infertile men with abnormal semen parameters (P < 0.01). There was also a significant positive correlation between OS markers with sperm DNA fragmentation (r = 0.59, P < 0.01 and r = 0.67, P < 0.01, respectively). We have found that imbalance between superoxide anion and peroxynitrite with antioxidant capacity in infertile men with abnormal sperm parameters is associated with higher sperm DNA fragmentation.

Vitrification versus slow freezing gives excellent survival, post warming embryo morphology and pregnancy outcomes for human cleaved embryos

PURPOSE

The objective of this retrospective study was to evaluate the efficacy of vitrification and slow freezing for the cryopreservation of human cleavage stage embryos in terms of post-warming survival rate, post-warming embryo morphology and clinical outcomes.

METHODS

The embryos of 305 patients at cleavage stages were cryopreserved either with vitrification (153 patients) or slow-freezing (152 patients) methods. After warming; the survival rate, post-warmed embryo morphology, clinical pregnancy and implantation rates were evaluated and compared between the two groups.

RESULT(S)

In the vitrification group versus slow freezing group, the survival rate (96.9% vs. 82.8%) and the post-warmed excellent morphology with all blastomeres intact (91.8% vs. 56.2%) were higher with an odds ratio of 6.607 (95% confidence interval; 4.184-10.434) and 8.769 (95% confidence interval; 6.460-11.904), respectively. In this group, the clinical pregnancy rate (40.5% vs. 21.4%) and the implantation rate (16.6% vs. 6.8%) were also higher with an odds ratio of 2.427 (95%confidence interval; 1.461-4.033) and 2.726 (95% confidence interval; 1.837-4.046), respectively.

CONCLUSION(S)

Vitrification in contrast to slow freezing is an efficient method for cryopreservation of human cleavage stage embryos. Vitrification provides a higher survival rate, minimal deleterious effects on post-warming embryo morphology and it can improve clinical outcomes.

Effect of laser zona pellucida opening on clinical outcome of assisted reproduction technology in patients with advanced female age, recurrent implantation failure, or frozen-thawed embryos

OBJECTIVE

To determine whether laser-assisted hatching can improve clinical outcome of assisted reproductive techniques in patients with advanced female age, with recurrent implantation failure, or who are using frozen-thawed embryos.

DESIGN

A prospective randomized study.

SETTING

The infertility and IVF unit at a research facility in Iran.

PATIENT(S)

Four hundred ten patients with advanced female age (> or =37 y), 796 patients with recurrent implantation failure (for > or =2 cycles), and 180 patients with frozen-thawed embryos.

INTERVENTION(S)

Patients were divided equally into test and control groups. On the day of embryo transfer, the zona pellucida of the selected embryos in the test group were opened about 40 mum by using an infrared optical laser system, whereas in the control group they were all intact.

MAIN OUTCOME MEASURE(S)

Clinical pregnancy rates and implantation rates.

RESULT(S)

In the patients with advanced female age or recurrent implantation failure, the clinical pregnancy and implantation rates were similar for the test and control groups. However, in the patients with frozen-thawed embryos, the rates were statistically significantly higher in the test group as compared with those of the control group (31.2% and 12.8% vs. 11.1% and 4.2%, respectively).

CONCLUSION(S)

The laser-assisted hatching improved the pregnancy and implantation rates in patients with frozen-thawed embryos but had no effect in patients with advanced female age or recurrent implantation failure.

Effect of fragment removal on blastocyst formation and quality of human embryos

Blastomere fragmentation is one of the most significant defects in cleaving embryos. Scientists believed that removing the fragments was a possible way to reduce their unwanted effects. This hypothesis has been tested in some studies in which the development of human fragmented embryos was followed in vivo after all fragments were removed, but little is known about the potential for in-vitro development of such embryos, which is the subject of the present study. For this purpose, 4-6 cell surplus human embryos were scored according to the degree and pattern of fragmentation into four grades, allocated into two groups of control and fragmentation removal (experimental) and cultured sequentially. At the end of day 6 of culture, in the experimental group especially in grade IV blastocyst rate, size and number of blastomeres in each blastocyst were all improved compared with those of the control group (42.3 versus 20.0%; 19,205.7 +/- 1060.3 versus 15,825.9 +/- 448.7 microm(2) and 100.14 +/- 13.48 versus 63.75 +/- 19.79 respectively, P < 0.05). In the grade IV embryos, apoptotic index was also significantly reduced after embryo fragmentation removal (3.40 +/- 0.88 versus 22.99 +/- 4.45, P < 0.05). In conclusion, fragmentation removal had a positive effect on human fragmented embryos and produced the best quality blastocysts.