Oocyte and embryo cryopreservation in assisted reproductive technology: past achievements and current challenges.

Cryopreservation has revolutionized the treatment of infertility and fertility preservation. This review summarizes the milestones that paved the way to the current routinary clinical implementation of this game-changing practice in assisted reproductive technology. Still, evidence to support "the best practice" in cryopreservation is controversial and several protocol adaptations exist that were described and compared here, such as cumulus-intact vs. cumulus-free oocyte cryopreservation, artificial collapse, assisted hatching, closed vs. open carriers, and others. A last matter of concern is whether cryostorage duration may impact oocyte/embryo competence, but the current body of evidence in this regard is reassuring. From social and clinical perspectives, oocyte and embryo cryopreservation has evolved from an afterthought when assisted reproduction was intended for immediate pregnancy with supernumerary embryos of secondary interest to its current purpose, which primarily is to preserve fertility long-term and more comprehensively allow for family planning. However, the initial consenting process, which still is geared to short-term fertility care, may no longer be relevant when the individuals that initially preserved the tissues have completed their reproductive journey. A more encompassing counseling model is required to address changing patient values over time.

Towards Automation in IVF: Pre-Clinical Validation of a Deep Learning-Based Embryo Grading System during PGT-A Cycles.

Preimplantation genetic testing for aneuploidies (PGT-A) is arguably the most effective embryo selection strategy. Nevertheless, it requires greater workload, costs, and expertise. Therefore, a quest towards user-friendly, non-invasive strategies is ongoing. Although insufficient to replace PGT-A, embryo morphological evaluation is significantly associated with embryonic competence, but scarcely reproducible. Recently, artificial intelligence-powered analyses have been proposed to objectify and automate image evaluations. iDAScore v1.0 is a deep-learning model based on a 3D convolutional neural network trained on time-lapse videos from implanted and non-implanted blastocysts. It is a decision support system for ranking blastocysts without manual input. This retrospective, pre-clinical, external validation included 3604 blastocysts and 808 euploid transfers from 1232 cycles. All blastocysts were retrospectively assessed through the iDAScore v1.0; therefore, it did not influence embryologists' decision-making process. iDAScore v1.0 was significantly associated with embryo morphology and competence, although AUCs for euploidy and live-birth prediction were 0.60 and 0.66, respectively, which is rather comparable to embryologists' performance. Nevertheless, iDAScore v1.0 is objective and reproducible, while embryologists' evaluations are not. In a retrospective simulation, iDAScore v1.0 would have ranked euploid blastocysts as top quality in 63% of cases with one or more euploid and aneuploid blastocysts, and it would have questioned embryologists' ranking in 48% of cases with two or more euploid blastocysts and one or more live birth. Therefore, iDAScore v1.0 may objectify embryologists' evaluations, but randomized controlled trials are required to assess its clinical value.

How slow is too slow? A comprehensive portrait of Day 7 blastocysts and their clinical value standardized through artificial intelligence.

STUDY QUESTION: What is the clinical value of Day 7 blastocysts? SUMMARY ANSWER: Ending embryo culture at 144 hours post-insemination (h.p.i.; i.e. 6 days) would involve 7.3% and 4.4% relative reductions in the number of patients obtaining euploid blastocysts and live birth(s) (LBs), respectively. WHAT IS KNOWN ALREADY: Many studies showed that Day 7 blastocysts are clinically valuable, although less euploid and less competent than faster-growing embryos. Nevertheless, a large variability exists in: (i) the definition of 'Day 7'; (ii) the criteria to culture embryos to Day 7; (iii) the clinical setting; (iv) the local regulation; and/or (v) the culture strategies and incubators. Here, we aimed to iron out these differences and portray Day 7 blastocysts with the lowest possible risk of bias. To this end, we have also adopted an artificial intelligence (AI)-powered software to automatize developmental timings annotations and standardize embryo morphological assessment. STUDY DESIGN, SIZE AND DURATION: Observational study including 1966 blastocysts obtained from 681 patients cultured in a time-lapse incubator between January 2013 and December 2020 at a private Italian IVF center. PARTICIPANTS/MATERIALS, SETTING, METHODS: According to Italian Law 40/2004, embryos were not selected based on their morphology and culture to ≥168 h.p.i. is standard care at our center. ICSI, continuous culture with Day 5 media refresh, trophectoderm biopsy without assisted hatching and comprehensive chromosome testing (CCT) to diagnose full-chromosome non-mosaic aneuploidies, were all performed. Blastocysts were clustered in six groups based on the time of biopsy in h.p.i. at 12 hr intervals starting from <120 h.p.i. (set as control) up to >168 h.p.i. Blastocyst quality was assessed using Gardner's scheme and confirmed with AI-powered software. AI was also used to automatically annotate the time of expanding blastocyst (tEB) and the hours elapsing between this moment and the achievement of full expansion when blastocysts were biopsied and vitrified. Also, blastocyst area at tEB and at the time of biopsy was automatically assessed, as well as the hour of the working day when the procedure was performed. The main outcomes were the euploidy rate and the LB rate (LBR) per vitrified-warmed euploid single blastocyst transfer. The results were adjusted for confounders through multivariate logistic regressions. To increase their generalizability, the main outcomes were reported also based on a 144-h.p.i. cutoff (i.e. 6 exact days from ICSI). Based on this cutoff, all the main patient outcomes (i.e. number of patients obtaining blastocysts, euploid blastocysts, LBs, with supernumerary blastocysts without a LB and with surplus blastocysts after an LB) were also reported versus the standard care (>168 h.p.i.). All hypothetical relative reductions were calculated. MAIN RESULTS AND THE ROLE OF CHANCE: A total of 14.6% of the blastocysts reached full expansion beyond 144 h.p.i. (5.9% in the range 144-156 h.p.i., 7.9% in the range 156-168 h.p.i. and 0.8% beyond 168 h.p.i.). Slower blastocysts were of a worse quality based on the evaluation of both embryologists and AI. Both later tEB and longer time between tEB and full blastocyst expansion concurred to Day 7 development, quite independently of blastocyst quality. Slower growing blastocysts were slightly larger than faster-growing ones at the time of biopsy, but no difference was reported in the risk of hatching, mainly because two dedicated slots have been set along the working day for these procedures. The lower euploidy rate among Day 7 blastocysts is due to their worse morphology and more advanced oocyte age, rather than to a slower development per se. Conversely, the lower LBR was significant even after adjusting for confounders, with a first relevant decrease for blastocysts biopsied in the range 132-144 h.p.i. (N = 76/208, 36.5% versus N = 114/215, 53.0% in the control, multivariate odds ratio 0.61, 95% CI 0.40-0.92, adjusted-P = 0.02), and a second step for blastocysts biopsied in the range 156-168 h.p.i. (N = 3/21, 14.3%, multivariate odds ratio: 0.24, 95% CI 0.07-0.88, adjusted-P = 0.03). Nevertheless, when the cutoff was set at 144 h.p.i., no significant difference was reported. In this patient population, ending embryo culture at 144 h.p.i. would have caused 10.6%, 7.3%, 4.4%, 13.7% and 5.2% relative reductions in the number of patients obtaining blastocysts, euploid blastocysts, LBs, supernumerary blastocysts without an LB and surplus blastocysts after an LB, respectively. LIMITATIONS, REASONS FOR CAUTION: Gestational and perinatal outcomes were not assessed, and a cost-effectiveness analysis is missing. Moreover, we encourage other groups to investigate this topic with different culture and biopsy protocols, as well as in different clinical settings and regulatory contexts. WIDER IMPLICATIONS OF THE FINDINGS: In view of the increasing personalization and patient-centeredness of IVF, whenever allowed from the local regulations, the choice to culture embryos to Day 7 should be grounded on the careful evaluation of couples' reproductive history. Patients should be aware that Day 7 blastocysts are less competent than faster-growing ones; still, poor prognosis couples, couples less compliant toward other attempts in case of a failure and couples wishing for more than one child, may benefit from them. AI tools can help improving the generalizability of the evidence worldwide. STUDY FUNDING/COMPETING INTEREST(S): This study did not receive any funding. I.E., A.B.M. and I.H.-V. are employees of Fairtility Ltd. TRIAL REGISTRATION NUMBER: N/A.

The paradox of the Italian clinical embryologist in the national public health system: hints towards harmonization of a postgraduate educational curriculum.

Clinical embryologists are highly trained laboratory professionals with multiple roles, including laboratory, clinical, biobanking and quality system management. In most European countries, clinical embryologists are trained to work in Medically Assisted Reproduction (MAR) centres without a specifically dedicated educational path. The criteria required for employment vary according to the educational structure and the public or private nature of the centre. We have herein described the educational profile required by Italian clinical embryologists to work in MAR centres of the National Health System (NHS). Public centres currently represent 36% of all the Italian MAR clinics. According to the Italian law, a future clinical embryologist must achieve a 3-4 year unpaid post-graduate specialization in a different field, choosing from Genetics, Microbiology, Clinical Pathology or Nutrition. Accesses to the above-mentioned post-graduate courses are themselves very limited. Clinical embryologists are basically trained by senior colleagues. This situation makes inevitably difficult to recruit laboratory staff in NHS centres. Moreover, it represents an emblematic example of the need for an equal training curriculum, possibly ensuring a comparable education quality, mobility of trainees and dissemination of skills for clinical embryologists all over Europe.

How 1 h of abstinence improves sperm quality and increases embryo euploidy rate after PGT-A: a study on 106 sibling biopsied blastocysts.

PURPOSE: The aim of our study was to evaluate the influence of different ejaculatory abstinence time frames (several days versus 1 h) on semen parameters, blastocysts ploidy rate, and clinical results in assisted reproduction cycles on sibling oocytes. METHODS: This is a prospective study including 22 preimplantation genetic testing for aneuploidy (PGT-A) cycles performed between November 2015 and December 2018. Male partners with oligoastenoteratozoospermia produced two semen samples on the day of oocyte retrieval: the first one after several days of abstinence and the second, 1 h after the first one. Oocytes from each patient were divided into two groups: those in group 1 were injected with spermatozoa from the first ejaculate (N = 121) and oocytes in group 2 with spermatozoa from the second one (N = 144). Outcomes of aniline blue test, fertilization, blastocyst formation, ploidy rates, and clinical results were compared between the two groups. RESULTS: Semen volume resulted lower in the second sperm retrieval. Sperm concentration, motility, and morphology were similar in the two groups. A total of 106 blasotcysts were biospied. Higher blastocyst euploidy rates resulted in group 2 (43.6%) than in group 1 (27.5%). A higher percentage of mature chromatine was observed in group 2. CONCLUSION: Using spermatozoa from samples with a shorter abstinence could be a simple method to select higher quality spermatozoa, reducing aneuploidy rate in blastocysts. Prospective randomized controlled trials should be performed to confirm the potential advantage of using semen samples with short abstinence period to improve the outcome of assisted reproduction cycles.

The aging male: Relationship between male age, sperm quality and sperm DNA damage in an unselected population of 3124 men attending the fertility centre for the first time.

OBJECTIVE: the aim of our study was to put forward insights to treat any possible correlation among sperm quality, sperm DNA damage and male age as they may have fertility implications for men who choose to delay fatherhood. MATERIALS AND METHODS: Our study is a non-interventional retrospective analysis of 3124 semen samples from patients that were investigated for the conventional semen parameters. Tunel test assay was set up for the evaluation of the sperm DNA fragmentation index (DFI). We applied the Kappa index to compare both the 1999 and the 2010 World Health Organization (WHO) reference criteria to evaluate the competence of such semen parameters categorization during the standard routine of our laboratory. RESULTS: With regards to our findings, it is possible to underline a significant relationship between aging and semen volume (p = 0.001), motility (p = 0.009), semen viscosity (p < 0.003) and sperm DNA damage (p < 0.009). We found a trend when focusing on the semen concentration (p = 0.05). The analysis of sperm morphology did not show any influence with advancing age (p = 0.606). When comparing both the 1999 and the 2010 WHO scales we found no accordance in the appraisal of sperm morphology but a very good one in the evaluation of the other parameters. CONCLUSIONS: Conventional semen analysis represents the opportunity to draw up a proxy insight on the male fertility status even if semen quality can only indirectly assess the probability of pregnancy. Several studies have verified a decay in the male reproductive system, sperm quality and fertility with advancing age although the reported results are not yet conclusive. Our results substantially agree with those findings outlined in the literature. Moreover we find that the discrepancy between the two WHO reference scales would eventually lead to an improper diagnosis of infertility.

Influence of human sperm origin, testicular or ejaculated, on embryo morphokinetic development.

In this retrospective observational study (October 2014 - July 2016), the impact of sperm origin on embryo morphokinetics and on clinical outcomes after intracytoplasmic sperm injection was evaluated. The developmental kinetics of embryos obtained either with testicular sperm (40 cycles; testicular sperm group) or with thawed donor sperm (26 cycles; donor sperm group) was analysed up to day-3 of culture with a time-lapse incubation system. In the testicular sperm group, all patients were affected by nonobstructive azoospermia. The timing of second polar body extrusion (IIPB), and the time to reach the 4-cells (t4) and 9-cells (t9) stages, differed significantly between the two groups: the IIPB extrusion and t4 were anticipated, whereas t9 was retarded in the testicular sperm group. We hypothesise that a different sperm maturation grade may influence the timing of embryo development: an early paternal effect of testicular sperm could be manifested as an anticipation in the IIPB extrusion and in the time for reaching the 4-cells stage. Conversely, a later paternal effect could be visible as a retardation in the timing at which the embryo reaches the 9-cells stage. Interestingly, clinical outcomes did not differ between the two groups except the implantation rate which was significantly increased in the donor sperm group.

Correlation between aneuploidy, standard morphology evaluation and morphokinetic development in 1730 biopsied blastocysts: a consecutive case series study.

STUDY QUESTION: Are there correlations among human blastocyst ploidy status, standard morphology evaluation and time-lapse kinetics? SUMMARY ANSWER: Correlations were observed, in that euploid human blastocysts showed a higher percentage with top quality inner cell mass (ICM) and trophectoderm (TE), higher expansion grades and shorter time to start of blastulation, expansion and hatching, compared to aneuploid ones. WHAT IS KNOWN ALREADY: Embryo quality has always been considered an important predictor of successful implantation and pregnancy. Nevertheless, knowledge of the relative impact of each morphological parameter at the blastocyst stage needs to be increased. Recently, with the introduction of time-lapse technology, morphokinetic parameters can also be evaluated. However, a large number of studies has reported conflicting outcomes. STUDY DESIGN, SIZE, DURATION: This was a consecutive case series study. The morphology of 1730 blastocysts obtained in 530 PGS cycles performed from September 2012 to April 2014 that underwent TE biopsy and array comparative genomic hybridization was analyzed retrospectively. A total of 928 blastocysts were cultured in a time-lapse incubator allowing morphokinetic parameters to be analyzed. PARTCIPANTS/MATERIALS, SETTING, METHOD: Mean female age was 36.8 ± 4.24 years. Four hunderd fifty-four couples were enrolled in the study: 384, 64 and 6 of them performed single, double or triple PGS cycles, respectively. In standard morphology evaluation, the expansion grade, and quality of the ICM and TE were analyzed. The morphokinetic parameters observed were second polar body extrusion, appearance of two pronuclei, pronuclear fading, onset of two- to eight-cell divisions, time between the two- and three-cell (cc2) and three- and four-cell (s2) stages, morulae formation time, starting blastulation, full blastocyst stage, expansion and hatching timing. MAIN RESULTS AND THE ROLE OF CHANCE: Of the 1730 biopsied blastocysts, 603 were euploid and 1127 aneuploid. We observed that 47.2% of euploid and 32.8% of aneuploid blastocysts showed top quality ICM (P < 0.001), and 17.1% of euploid and 28.5% of aneuploid blastocysts showed poor quality ICM (P < 0.001). Top quality TE was present in 46.5% of euploid and 31.1% of aneuploid blastocysts (P < 0.001), while 26.6% of euploid and 38.1% of aneuploid blastocysts showed poor quality TE (P < 0.001). Regarding expansion grade, 81.1% of euploid and 72.4% of aneuploid blastocysts were fully expanded (Grade 5-6; P < 0.001). The timing of cleavage from the three- to four-cell stage, of reaching four-cell stage, of starting blastulation, reaching full blastocyst stage, blastocyst expansion and hatching were 2.6 (95% confidence interval (CI): 1.7-3.5), 40.0 (95% CI: 39.3-40.6), 103.4 (95% CI: 102.2-104.6), 110.2 (95% CI: 108.8-111.5), 118.7 (95% CI: 117.0-120.5) and 133.2 (95% CI: 131.2-135.2) hours in euploid blastocysts, and 4.2 (95% CI: 3.6-4.8), 41.1 (95% CI: 40.6-41.6), 105.0 (95% CI: 104.0-106.0), 112.8 (95% CI: 111.7-113.9), 122.1 (95% CI: 120.7-123.4) and 137.4 (95% CI: 135.7-139.1) hours in aneuploid blastocysts (P < 0.05 for early and P < 0.0001 for later stages of development), respectively. No statistically significant differences were found between euploid and aneuploid blastocysts for the remaining morphokinetic parameters.A total of 407 embryo transfers were performed (155 fresh, 252 frozen-thawed blastocysts). Higher clinical pregnancy, implantation and live birth rates were obtained in frozen-thawed compared to fresh embryo transfers (P = 0.0104, 0.0091 and 0.0148, respectively). The miscarriage rate was 16.1% and 19.6% in cryopreserved and fresh embryo transfer, respectively. The mean female age was lower in the euploid compared to aneuploid groups (35.0 ± 3.78 versus 36.7 ± 4.13 years, respectively), We found an increasing probability for aneuploidy with female age of 10% per year (odds ratio (OR) = 1.1, 95% CI: 1.1-1.2, P < 0.001). LIMITATIONS, REASONS FOR CAUTION: The main limitation of morphology assessment is that it is a static system and can be operator-dependent. In this study, eight embryologists performed morphology assessments. The main limitation of the time-lapse technology is that it is impossible to rotate the embryos making it very difficult to observe them in case of blastomere overlapping or increased cytoplasmic fragmentation. WIDER IMPLICATIONS OF THE FINDINGS: Although there seems to be a relationship between the ploidy status and blastocyst morphology/development dynamics, the evaluation of morphological and morphokinetic parameters cannot currently be improved upon, and therefore replace, PGS. Our results on ongoing pregnancy and miscarriage rates suggest that embryo evaluation by PGS or time-lapse imaging may not improve IVF outcome. However, time-lapse monitoring could be used in conjunction with PGS to choose, within a cohort, the blastocysts to analyze or, when more than one euploid blastocyst is available, to select which one should be transferred. STUDY FUNDING/COMPETING INTERESTS: No specific funding was obtained for this study. None of the authors have any competing interests to declare.

A novel stepwise micro-TESE approach in non obstructive azoospermia.

BACKGROUND: The purpose of the study was to investigate whether micro-TESE can improve sperm retrieval rate (SRR) compared to conventional single TESE biopsy on the same testicle or to contralateral multiple TESE, by employing a novel stepwise micro-TESE approach in a population of poor prognosis patients with non-obstructive azoospermia (NOA). METHODS: Sixty-four poor prognosis NOA men undergoing surgical testicular sperm retrieval for ICSI, from March 2007 to April 2013, were included in this study. Patients inclusion criteria were a) previous unsuccessful TESE, b) unfavorable histology (SCOS, MA, sclerahyalinosis), c) Klinefelter syndrome. We employed a stepwise micro-TESE consisting three-steps: 1) single conventional TESE biopsy; 2) micro-TESE on the same testis; 3) contralateral multiple TESE. RESULTS: SRR was 28.1 % (18/64). Sperm was obtained in both the initial single conventional TESE and in the following micro-TESE. The positive or negative sperm retrieval was further confirmed by a contralateral multiple TESE, when performed. No significant pre-operative predictors of sperm retrieval, including patients' age, previous negative TESE or serological markers (LH, FSH, inhibin B), were observed at univariate or multivariate analysis. Micro-TESE (step 2) did not improve sperm retrieval as compared to single TESE biopsy on the same testicle (step 1) or multiple contralateral TESE (step 3). CONCLUSIONS: Stepwise micro-TESE could represent an optimal approach for sperm retrieval in NOA men. In our view, it should be offered to NOA patients in order to gradually increase surgical invasiveness, when necessary. Stepwise micro-TESE might also reduce the costs, time and efforts involved in surgery.

Analysis of MYO-Inositol effect on spermatozoa motility, in hyper viscous ejaculates and in patients with grades II and III varicocele.

The goal of this study is to evaluate MYOInositol effects on spermatozoa motility, in patients' ejaculates with severe varicocele or hyper viscosity. The study included normal viscosity ejaculate from 30 patients affected by varicocele and hyper viscosity ejaculate from 33 patients without any testicular pathologies. All selected samples showed sperm concentration > 2 million/ml and progressive motility < 32%. In both groups, the pellet obtained after centrifugation in buffered medium, was divided in two aliquots, both incubated for 15 minutes at 37°C: one with MYO-Inositol and the other one, as control, only in phosphate buffered saline (PBS). Afterwards, the sperm progressive motility was assessed using Computer Assisted Sperm Analysis (CASA system). Incubation with MYO-Inositol improved sperm progressive motility in high viscosity samples compared to control group (38.9% ± 3.0 vs 24.35% ± 2.41, respectively; p ≤ 0.0001). Conversely, no statistically significant difference was observed in total sperm progressive motility in varicocele samples compared with control group (22.7% ± 2.07 vs 26.7% ± 3.31, respectively; p = 0.085). The MYO-Inositol positive effect on spermatozoa motility may depend on the type of sperm damage: heavy structural and biochemical defects which typically affects patients with varicocele are not restored by Inositol. On the contrary, MYOInositol is able to improve sperm motility in semen samples with high viscosity, since those samples show no substantial structural sperm defects.

Improved blastocyst formation with reduced culture volume: comparison of three different culture conditions on 1128 sibling human zygotes.

PURPOSE: The aim of the present randomized, comparative study was to evaluate the effect of reduced culture volumes on sibling human embryo development. METHODS: Firstly, sibling injected oocytes obtained from 88 out of 165 consenting couples undergoing infertility treatment were cultured either in large (35 µl) or in small drops (15 µl) of culture medium. Secondly, sibling injected oocytes from 77 couples were cultured either in large (35 µl) or in mini drops (7 µl). Embryo quality on day-2 and day-3 and blastocyst formation rate on day-5 were evaluated. RESULTS: No statistically significant difference in terms of embryo quality was detected comparing embryos cultured either in large (35 µl) or small (15 µl) drops until blastocyst stage. Similarly, no difference appeared between large (35 µl) or mini (7 µl) drops until day-3, however a significantly higher blastocyst formation rate was observed in mini (7 µl) drops on day-5. CONCLUSIONS: Reduced culture volume seems not to influence early embryo development but a reduction of medium appears to positively affect blastocyst development. This supports the hypothesis that the pre-implantation embryo produces autocrine factors which exert a positive effect on embryo development when culture is performed in a reduced volume.

Traditional intracytoplasmic sperm injection provides equivalent outcomes compared with human zona pellucida-bound selected sperm injection.

The capability of human zona pellucida (ZP) to bind selectively to normal functional sperm with normal chromatin has been reported widely in the literature. The aim of this study was to evaluate whether ZP-binding sperm selection may represent a method to retrieve superior spermatozoa for intracytoplasmic sperm injection (ICSI). Patients were divided into two groups: a ZP-ICSI and a conventional ICSI group. In the ZP-ICSI group, spermatozoa for injection were selected after ZP-sperm incubation and spermatozoa that were tightly bound to the ZP were used for ICSI (ZP-ICSI). Clinical outcomes of ZP-ICSI were compared with the outcomes of traditional scientist-selected sperm injection (conventional ICSI). Results did not show any significant difference in fertilization, pregnancy, implantation and take-home-baby rates between conventional ICSI and ZP-ICSI. However, when data relative to patients who received ZP-ICSI were analyzed, an interesting result was observed: higher sperm concentration and morphology correlated with higher ZP-sperm binding. Additionally, patients with higher ZP-sperm binding seem to have improved pregnancy and take-home-baby rates. In conclusion, this study shows that ZP-ICSI is not a superior method compared with conventional ICSI. However, clinical ICSI outcomes were apparently improved in the presence of good ZP-sperm binding. We therefore speculate that sperm competence to ICSI could be reduced when the sperm's ability to bind the ZP is impaired.

Efficiency of slush nitrogen vitrification of human oocytes vitrified with or without cumulus cells in relation to survival rate and meiotic spindle competence.

OBJECTIVE: To evaluate the efficiency of slush nitrogen vitrification of human oocytes with or without cumulus cells in terms of survival rate and maintenance of meiotic spindle. DESIGN: Randomized, comparative study. SETTING: Medical center. PATIENT(S): A total of 274 oocytes obtained from 46 couples undergoing infertility treatment. INTERVENTION(S): Metaphase II oocytes were divided into groups A and B, vitrified with and without cumulus cells, respectively. MAIN OUTCOMES MEASURE(S): Survival rates and maintenance of meiotic spindle observed immediately after warming and 3 hours after incubation. RESULT(S): No statistically significant difference was detected between the two groups in terms of survival rate, but a significantly higher percentage of detectable spindle was observed in group B (completely denuded oocytes), either immediately after warming or 3 hours after incubation. CONCLUSION(S): Complete denudation of oocytes before slush nitrogen vitrification does not influence survival rates but positively affects oocyte meiotic spindle competence. These data support the hypothesis that cumulus cells during vitrification represent an obstacle to cryoprotectant penetration more than having a protective role for the oocyte.

Effect of calcium ionophore A23187 on prostaglandin synthase type 2 and 15-hydroxy-prostaglandin dehydrogenase expression in human chorion trophoblast cells.

OBJECTIVE: Prostaglandins induce parturition in humans. Prostaglandin output is regulated by the synthetic and metabolic enzymes, prostaglandin synthase type 2 (PTGS2) and 15-hydroxyprostaglandin dehydrogenase (PGDH). The role of calcium in regulating PTGS2 and PGDH expression was investigated in chorion trophoblasts. STUDY DESIGN: Cells were treated with calcium ionophore A23187 in the presence or absence of calcium chelators; changes in messenger ribonucleic acid expression were measured with real-time polymerase chain reaction and analyzed with analysis of variance. Protein expression was evaluated with Western blot and dual immunofluorescence. RESULTS: A23187 stimulated PTGS2 and suppressed PGDH expression. Effects of A23187 were reversed by calcium chelators. PTGS2 had perinuclear and cytosolic distribution, whereas PGDH was cytosolic. Some cells expressed both enzymes, some neither enzyme, and some either PTGS2 or PGDH. CONCLUSION: Chorion cells showed heterogeneity in the expression of PTGS2 and PGDH. Calcium influx regulates PTGS2 and PGDH expression, thereby promoting coordinated increased prostaglandin output in circumstances such as term and preterm labor.

Opposite effect of phorbol ester PMA on PTGS2 and PGDH mRNA expression in human chorion trophoblast cells.

Prostaglandins (PGs) induce the mechanism of labor in humans. The enzymes responsible for PG synthesis and metabolism are prostaglandin-endoperoxide synthase 2 (PTGS2) and 15-hydroxyprostaglandin dehydrogenase (PGDH). In human chorion trophoblast cells, calcium ionophore A23187 upregulates PTGS2 and downregulates PGDH protein and mRNA. The authors hypothesize that this regulation requires activation of protein kinase C (PKC) and mitogen-activated protein kinases (MAPKs). Human chorion trophoblasts were incubated with A23187 or phorbol 12-myristate 13-acetate (PMA) in the absence or presence of inhibitors of PKC, c-Jun N-terminal kinase, p38, and MEK1/2. PTGS2 and PGDH mRNA were measured by real-time reverse-transcription polymerase chain reaction. PMA upregulated PTGS2 and downregulated PGDH. The PMA effect was reversed by the inhibition of PKC. The p38 inhibitor reduced the stimulatory effect of PMA and A23187 on PTGS2. MEK1/2 inhibitor reduced the effect of PMA on PTGS2. All MAPK inhibitors failed to reverse the effect of either A23187 or PMA on PGDH. The authors conclude that upon stimulation with the same upstream signals, different downstream intracellular pathways regulate PTGS2 and PGDH mRNA expression.

Localization and distribution of adrenomedullin receptor in the human placenta: changes with gestational age.

OBJECTIVE: To examine the distribution and localization of adrenomedullin (AM) receptor (AM-R) in human placenta and fetal membranes to assess any change during pregnancy or with labor. STUDY DESIGN: Immunohistochemistry was performed by the avidin/biotin immunoperoxidase method using an antibody specific to AM-R on intrauterine tissues collected from 7-41 weeks of gestation (n=73). RESULTS: AM-R was localized in the placenta and fetal membranes in all 3 trimesters. The distribution of AM-R in the villous and extravillous trophoblast cells of the placenta and in chorion and decidua cells of the fetal membranes changed with gestational age but not with labor. CONCLUSION: AM is secreted by decidua and trophoblast cells that also possess AM-R, suggesting that placental tissues function in both the synthesis and action of AM. Changes in AM-R in the placenta during pregnancy may reflect changes in AM function throughout gestation.