MM. Analyzing Cell-free Genomic DNA in Spent Culture Media: Noninvasive Insight into the Blastocysts

A commonly accepted standard protocol for noninvasive techniques for the genetic evaluation of an embryo remains elusive due to inconclusiveness regarding the volume of spent media to be acquired and the possibility of acquiring the same for subsequent analysis. Single embryo culture is imperative for standardizing noninvasive preimplantation testing using cell-free DNA (cf-DNA) released by individual developing embryos. This study aims to compare the development dynamics of single-drop embryonic culture against with group embryonic culture to establish a standardized protocol for noninvasive Preimplantation Genetic Testing (PGT) in bovine. A total of 239 cumulus-oocyte complexes were aspirated and subjected to in vitro maturation and fertilization. Among these, 120 embryos of day 3 were transferred to single-drop culture until the blastocyst stage. The single-drop culture drops were prepared using microdrops of 30 μL. At the blastocyst stage, spent media from all single-drop embryos were utilized for extracting cell-free genomic DNA to standardize the protocol. The blastocyst rate indicates no significant difference between the two culture methods, suggesting that single-drop culture is suitable for the process. Additionally, the extracted spent media yielded sufficient quantities of cf-DNA, supporting its potential use for PGT ( p  < 0.05). These findings support the hypothesis that single-drop embryo culture is a viable method for cf-DNA extraction and confirm the potential of using DNA fragments from spent media as a reliable source for noninvasive PGT.

Individually Cultured Bovine Zygotes Successfully Develop to the Blastocyst Stage in an Extremely Confined Environment

The possibility of detecting the developmental competence of individually cultured embryos through analysis of spent media is a major current trend in an ART setting. However, individual embryo culture is detrimental compared with high-density group culture due to the reduced concentration of putative embryotropins. The main aim of this study was to identify an individual culture system that is not detrimental over high-density group culture in the bovine model. Blastocyst rates and competence were investigated in a conventional (GC) group, semi-confined group (MG), and individual culture (MS) in a commercial microwell device. Main findings showed that: (1) individual embryos can be continuously cultured for 7 days in ~70 nL microwells (MS) without detrimental effects compared with the GC and MG; (2) MS and MG blastocysts had a reduced number of TUNEL-positive cells compared to GC blastocysts; (3) though blastocyst mean cell numbers, mitochondrial activity, and lipid content were not different among the three culture conditions, MS blastocysts had a higher frequency of small-sized lipid droplets and a reduced mean droplet diameter compared with GC and MG blastocysts. Overall, findings open the way to optimize the development and competence of single embryos in an ART setting.

Enhancement of preimplantation mouse embryo development with optimized in vitro culture dish via stabilization of medium osmolarity

OBJECTIVE

We evaluated the efficacy of the newly developed optimized in vitro culture (OIVC) dish for cultivating preimplantation mouse embryos. This dish minimizes the need for mineral oil and incorporates microwells, providing a stable culture environment and enabling independent monitoring of individual embryos.

METHODS

Mouse pronuclear (PN) zygotes and two-cell-stage embryos were collected at 18 and 46 hours after human chorionic gonadotropin injection, respectively. These were cultured for 120 hours using potassium simplex optimized medium (KSOM) to reach the blastocyst stage. The embryos were randomly allocated into three groups, each cultured in one of three dishes: a 60-mm culture dish, a microdrop dish, and an OIVC dish that we developed.

RESULTS

The OIVC dish effectively maintained the osmolarity of the KSOM culture medium over a 5-day period using only 2 mL of mineral oil. This contrasts with the significant osmolarity increase observed in the 60-mm culture dish. Additionally, the OIVC dish exhibited higher blastulation rates from two-cell embryos (100%) relative to the other dish types. Moreover, blastocysts derived from both PN zygotes and two-cell embryos in the OIVC dish group demonstrated significantly elevated mean cell numbers.

CONCLUSION

Use of the OIVC dish markedly increased the number of cells in blastocysts derived from the in vitro culture of preimplantation mouse embryos. The capacity of this dish to maintain medium osmolarity with minimal mineral oil usage represents a breakthrough that may advance embryo culture techniques for various mammals, including human in vitro fertilization and embryo transfer programs.

Oocyte developmental capacity is influenced by intrinsic ovarian factors in a bovine model for individual embryo production

The ovary and its hormones may have major effects on the in vitro developmental capacity of the oocytes it contains. We related intrinsic ovarian factors namely the presence of corpus luteum (CL) and/or dominant follicle (>8 mm) and the follicular count to cumulus expansion (CE), embryo development, and blastocyst quality in a bovine model. Cumulus-oocyte-complexes (COCs) were aspirated from follicles between 4 and 8 mm in diameter. In vitro embryo production was performed in a fully individual production system. The follicular fluid from which COCs were collected was pooled (per ovary) to evaluate the estrogen, progesterone, and insulin-like growth factor-1 (IGF-1) concentrations. Cumulus oocyte complexes collected from ovaries without a CL presented a greater CE than COCs derived from ovaries bearing CL. The absence of ovarian structures increased the blastocyst rate when compared to oocytes derived from ovaries with a CL, a dominant follicle, or both. Blastocysts derived from ovaries without a dominant follicle presented higher total cell numbers and a lower proportion of apoptosis than blastocysts derived from ovaries containing a dominant follicle. Cumulus oocyte complexes collected from ovaries with high follicular count resulted in higher cleavage than from ovaries with low follicular count, but the blastocyst rate was similar between groups. Ovaries bearing a CL had greater progesterone and IGF-1 follicular fluid concentrations in neighboring follicles than ovaries without a CL. Selection for bovine ovaries without CL or dominant follicle can have positive effects on CE, embryo development, and blastocyst quality in an individual embryo production system set-up.

Prospective-randomized study comparing clinical outcomes of IVF treatments where embryos were cultured individually or in a microwell group culture dish

Culturing embryos together in a microdrop of media may improve embryo quality, based on the results of animal studies, however individual identification of the embryos in such a system is not possible. The microwell group culture dish contains 9 or 16 microwells with a minimal well-to-well distance and a specific well morphology that facilitates paracrine and autocrine effects. The microwell group culture dish enables individual identification of the embryos while providing the environment that comes with similar benefits as group culture. Our aim was to investigate whether embryo culture in the microwell group culture dish (Primo Vision Dish, Vitrolife) improves IVF outcomes compared to individual culture in human IVF treatment. Five hundred thirty-two IVF-ET cycles were enrolled in this prospective randomized study in a university hospital. IVF cycles were randomized into microwell group culture and individual culture groups. Primary outcome measure was clinical pregnancy rate and secondary outcome measures were embryo quality, fertilization, implantation, delivery and embryo utilization rates. Fertilization rate in ICSI cycles was significantly higher in the microwell group culture group (70.6% vs. 64.9%, P = 0.001). Clinical pregnancy rate was 50.8% in the group culture and 40.6% in the individual culture (P = 0.022). Live birth rate was 41.5% in microwell and 32.9% in individual culture (P = 0.0496). Embryo utilization rate was higher in microwell group culture than in individual culture (80.6% vs. 75.0%; P < 0.001). Microwell group culture has a beneficial effect on IVF outcome and it also allows following up individual embryo development.ClinicalTrials.gov: NCT01774006.

Fused blastocysts as a consequence of group embryo culture: observations, complications, and potential solutions

How embryos are cultured, in groups or individually, can influence their development and have other unforeseen impacts on subsequent assisted reproductive technologies. Although a group culture of embryos improves the blastocyst formation rates, this can create conditions wherein separate blastocysts may fuse. This fusion of 2 blastocysts can create unique logistic issues for embryo biopsy and genetic analysis. New culture approaches have emerged to facilitate individual embryo culture without losing the benefit of the group culture approach. Unique culture dishes and adjustments of laboratory culture/embryo handling protocols offer possible solutions to minimize or avoid blastocyst fusion.

Individual culture leads to decreased blastocyst formation but does not affect pregnancy outcomes in the setting of a single, vitrified-warmed euploid blastocyst transfer

PURPOSE

To evaluate embryology and pregnancy outcomes following individual and group embryo culture in the setting of contemporary laboratory practices and freeze-all cycles.

METHODS

Patients underwent ovarian stimulation followed by intracytoplasmic sperm injection (ICSI). Embryos proceeded through individual culture and then underwent preimplantation genetic testing for aneuploidy (PGT-A) via trophectoderm biopsy. In a subsequent cycle, participants underwent single embryo transfer of a vitrified-warmed, euploid embryo. Outcomes were compared to controls undergoing group culture during the same time frame. The Mann-Whitney U test and logistic regression models were utilized.

RESULTS

Outcomes were assessed for 144 patients whose embryos underwent individual culture and 449 controls whose embryos underwent group culture. There were no significant differences in fertilization rates between groups (81.7% for individual culture vs. 84.1% for group culture, p = 0.22). However, individual culture was associated with a decreased rate of blastocyst formation compared to group culture (43.5% vs. 48.5%, p < 0.01). Following single, vitrified-warmed euploid blastocyst transfer, there were no significant differences between individual culture and group culture, respectively, in rates of positive βhCG (81.9% vs. 81.5%, p = 0.91), sustained implantation (63.9% vs. 65.0%, p = 0.80), biochemical miscarriage (16.7% vs. 12.3%, p = 0.18), or clinical miscarriage (1.4% vs. 4.2%, p = 0.13).

CONCLUSION

While individual culture appears to negatively impact the rate of usable blastocyst formation compared to group culture, there were no significant differences in pregnancy outcomes following transfer of a single, vitrified-warmed euploid blastocyst.

Toward a predictive theoretical model for osmolality rise with non-humidified incubation: a randomized, multivariate response-surface study

STUDY QUESTION

What factors associated with embryo culture techniques contribute to the rate of medium osmolality change over time in an embryo culture incubator without added humidity?

SUMMARY ANSWER

The surface area-to-volume ratio of culture medium (surface area of the medium exposed to an oil overlay), as well as the density and height of the overlaying oil, all interact in a quantitative way to affect the osmolality rise over time.

WHAT IS KNOWN ALREADY

Factors such as medium volume, different oil types, and associated properties, individually, can affect osmolality change during non-humidified incubation.

STUDY DESIGN, SIZE, DURATION

Several experimental designs were used, including simple single-factor completely randomized designs, as well as a multi-factor response surface design. Randomization was performed at one or more levels for each experiment. Osmolality measurements were performed over 7 days, with up to 8 independent osmolality measurements performed per treatment group over that time. For the multi-factor study, 107 independent combinations of factor levels were assessed to develop the mathematical model.

PARTICIPANTS/MATERIALS, SETTING, METHODS

This study was conducted in a research laboratory setting. Commercially available embryo culture medium and oil was used. A MINC incubator without water for humidification was used for the incubation. Osmolality was measured with a vapor pressure osmometer after calibration. Viscometry and density were conducted using a rheometer, and volumetric flasks with an analytical balance, respectively. Data analyses were conducted with several commercially available software programs.

MAIN RESULTS AND THE ROLE OF CHANCE

Preliminary experiments showed that the surface area-to-volume ratio of the culture medium, oil density, and oil thickness above the medium all contributed significantly (P < 0.05) to the rise in osmolality. A multi-factor experiment showed that a combination of these variables, in the form of a truncated cubic polynomial, was able to predict the rise in osmolality, with these three variables interacting in the model (P < 0.05). Repeatability, as measured by the response of identical treatments performed independently, was high, with osmolality values being ± 2 of the average in most instances. In the final mathematical model, the terms of the equation were significant predictors of the outcome, with all P-values being significant, and only one P-value > 0.0001.

LIMITATIONS, REASONS FOR CAUTION

Although the range of values for the variables were selected to encompass values that are expected to be encountered in usual embryo culture conditions, variables outside of the range used may not result in accurate model predictions. Although the use of a single incubator type and medium type is not expected to affect the conclusions, that remains an uncertainty.

WIDER IMPLICATIONS OF THE FINDINGS

Using this predictive model will help to determine if one should be cautious in using a specific system and will provide guidance on how a system may be modified to provide improved stability during embryo culture.

STUDY FUNDING/COMPETING INTEREST(S)

This study was funded by Cook Medical. The author is a Team Lead and Senior Scientist at Cook Medical. The author has no other conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

Evaluating the value of day 0 of an ICSI cycle on indicating laboratory outcome

A number of oocyte characteristics have been associated with fertilization, implantation and live-birth rates, albeit without reaching a consensus. This study aims to delineate possible associations between oocyte characteristics, oocyte behavior during intracytoplasmic sperm injection (ICSI), fertilization potential, and laboratory outcomes. Four-hundred and seventy-seven patients, yielding 3452 oocytes, were enrolled in this prospective observational study from 2015 to 2018. Οoplasm granularity was associated with poor embryo quality and higher probabilities of post-ICSI oocytes and embryos discarded in any developmental stage and never selected for embryo transfer or cryopreservation (p < 0.001). Both sudden or difficult ooplasm aspiration, and high or lack of resistance during ICSI were associated with either a poor Zygote-Score or fertilization failure (p < 0.001). Sudden or difficult ooplasm aspiration and high resistance during ICSI penetration were positively associated with resulting to a post-ICSI oocyte or embryo that would be selected for discard. Evaluation of oocyte characteristics and oocyte behavior during ICSI may provide early information regarding laboratory and cycle outcomes. Particularly, ooplasm granularity, and fragmentation of polar body, along with sudden or difficult ooplasm aspiration and high or lack of resistance during ICSI penetration may hinder the outcome of an ICSI cycle. The associations presented herein may contribute towards development of a grading system or a prediction model. Taking into account information on oocytes and ICSI behavior may effectively assist in enhancing IVF outcome rates.

Embryo's Natural Motion (enMotion): a paired randomized controlled trial evaluating a dynamic embryo culture system

OBJECTIVE

To determine if a dynamic embryo culture system affects the reproductive potential of human embryos resulting from in vitro fertilization (IVF).

DESIGN

Paired randomized controlled trial (RCT).

SETTING

IVF center.

PATIENT(S)

IVF patients with normal ovarian reserve eligible for two-embryo transfer.

INTERVENTION

IVF care was routine until fertilization was confirmed. Two-pronuclear embryos (2PNs) were then randomized: One-half of each patient's 2PNs were cultured in dynamic culture and one-half in static culture. Preimplantation genetic testing for embryonic aneuploidy was used to control for aneuploidy and allow for DNA fingerprinting. The best euploid blastocyst from each culture system was selected and patients underwent a frozen two-embryo transfer. If a singleton gestation resulted, DNA-fingerprinting was used to determine which of the two blastocysts implanted. The dynamic platform used was the NSSB-300 (Nepagene).

MAIN OUTCOME MEASURE(S)

The primary outcome was the proportion of usable blastocysts obtained. The secondary outcome was sustained implantation rate (SIR).

RESULT(S)

One hundred participants completed oocyte retrieval and blastocyst vitrification for frozen-thawed embryo transfer; 609 dynamic 2PNs and 615 static 2PNs were followed; and 304 blastocysts developed in dynamic culture and 333 blastocysts developed in static culture. In the paired analysis, the rate of usable blastulation was similar between dynamic and static culture (58.3% vs. 57.1%). In addition, there was no difference in the rate of aneuploidy (20.0% vs. 33.3%) or SIR (67.1% vs. 63.1%) between groups.

CONCLUSION(S)

In this paired RCT, dynamic culture did not improve usable blastulation rate or SIR.

CLINICAL TRIAL REGISTRATION NUMBER

NCT02467725.

Systematic Development, Validation and Optimization of a Human Embryo Culture System

Objective: To develop and validate a reliable in vitro culture system for human embryos. Design: Retrospective analyses of a series of four studies were conducted between 2006 and 2010 to assess the effect of incubator type (CO2 box versus Tri-gas minibox), media type, oil type, and hyaluronate supplementation. Optimization of in vitro blastocyst development was verified by assessing our National CDC/ART Surveillance reports between 2010 and 2016. Material and Methods: All patients experienced controlled ovarian hyperstimulation, followed by egg retrieval 35 h post-hCG. Cumulus-oocyte complexes were temporarily cultured in P1 or LG Fert medium plus HSA. Eggs were moved to a more complex media (G-medium or Global®-LG medium) containing a synthetic protein and embryo adhesion supplement (SPS and EAS, respectively; mLG) post-ICSI insemination. Zygotes were assigned to group culture in 25 µl droplets under oil (light mineral oil or paraffin oil; 37 °C) and embryo development was evaluated on Days 3, 5, and 6 and transferred on Day 3 to 5 depending on the number/quality of embryos available and the IVF history of the patient. Transfers were performed under ultrasound guidance, primarily using a Sureview-Wallace catheter, and enriched ET medium containing 500 µg/mL EAS. Results: Pilot study results (Expt. 1) showed that a mLG single-step medium could be effectively used in combination with Sanyo MCO-5 tri-gas (TG) incubators. Once adapted to SCIRS Lab in 2007 (Expt. 2), the latter culture system yielded improved blastocyst production and pregnancy outcomes compared to CO2 in air sequential incubation in P1/Multi-blast medium. In Expt. 3, the mLG/TG system yielded high levels of ≥2BB quality blastocysts (51 to 66%) across all age groups, and greater (p < 0.05) pregnancy success/live birth rates using fewer embryos transferred on Day 5 versus Day 3. After validating its clinical effectiveness, mLG was then prospectively compared to a new generation G-media (1.5 & 2.5; Expt. 4) and determined that the crossover treatment using paraffin oil (Ovoil™) allowed the mLG system to be optimized. Subsequently, a compilation of our Annual CDC/ART reported data over six years verified the overall viability of in vitro cultured and vitrified blastocysts produced in the mLG/TG system. Conclusion: By systematically evaluating and implementing various components of an embryo culture system we were able to optimize blastocyst development over the last decade. Our mLG/TG culture system modified an exceptionally well designed KSOMAA LG medium using endotoxin-free EAS and SPS additives to support cellular membrane wellness under stressful in vitro conditions (e.g., culture, cell biopsy, vitrification). Our use of the mLG/TG culture system has proven to be effective, creating reliably high blastocyst production, implantation, and healthy live births.

Production of piglets from in vitro-produced blastocysts by ultrasound-guided ovum pick-up from live donors

The objective of this research was to develop a system for piglet production by transvaginal ultrasound-guided ovum pick-up (OPU), in vitro production (IVP) of embryos and embryo transfer. First, to establish a culture system for a small number of oocytes or embryos, we evaluated the effect of different incubation volumes and culture densities on fertilizing ability and developmental competence in vitro. Porcine oocytes derived from slaughterhouse ovaries were matured, fertilized and then cultured in vitro in groups as follows: 50 oocytes in 500 μL medium for IVM, 20 oocytes in 100 μL medium for IVF and 20 embryos in 40 μL medium for IVC (Group I); 20 in 100 μL for IVM, 20 in 100 μL for IVF and 20 in 40 μL for IVC (Group II); and 10 in 100 μL for IVM, 10 in 100 μL for IVF and 10 in 40 μL for IVC (Group III). Percentages of sperm penetration, cleavage and blastocyst formation did not differ among the groups. Second, to increase the collection efficiency of porcine oocytes by transvaginal ultrasound-guided OPU, the effects of aspiration pressure on follicular oocyte collection were assessed. Oocytes were aspirated from ovaries of live sows using 80 or 100 mmHg. The recovered oocytes were divided into four categories according to the surrounding cumulus cells and quality of oocytes. The number of oocytes recovered using 100 mmHg pressure was significantly higher than with 80 mmHg pressure. However, there were no significant differences in the population of oocytes grouped by the morphological criteria, number of blastocysts per session and the total cell number in blastocysts between the two vacuum pressures. Finally, 81 oocytes obtained by OPU from five donor sows were subjected to IVP and 47 transferable embryos (9.4 ± 4.0 [mean ± SD] morulae/blastocysts per session) were obtained at 5 days after IVF. When they were transferred into five recipient gilts (5-16 embryos per recipient), three of five recipients became pregnant and farrowed a total of 12 live piglets. The present results demonstrate that porcine blastocysts can be produced by OPU-IVP and develop to full term after embryo transfer.

A novel embryo culture media supplement that improves pregnancy rates in mice

The preimplantation embryoinvivois exposed to numerous growth factors in the female reproductive tract, which are not recapitulated in embryo culture mediain vitro. The IGF2 and plasminogen activator systems facilitate blastocyst development. We hypothesized that the addition of IGF2 in combination with urokinase plasminogen activator (uPA) and plasminogen could improve rates of blastocyst hatching and implantation in mice. B6BcF1 and CBAB6F2 mouse embryos were divided into one of four supplemented culture media treatment groups: (1) control (media only); (2) 12.5 nM IGF2; (3) 10 µg/mL uPA and 5 µg/mL plasminogen; or (4) a combination of IGF2, uPA and plasminogen treatments. Embryo development to blastocyst stage and hatching were assessed before transfer to pseudopregnant recipient females and implantation, pregnancy rates and postnatal growth were assessed. After 90.5 h of culture, IGF2 + U + P treatment increased the percentage of B6BcF1 embryos that were hatching/hatched and percentage developing to blastocyst stage compared with controls (P < 0.02). Following B6BcF1 embryo transfer, IGF2 + U + P treatment increased implantation sites at day 8 of pregnancy compared with controls (P < 0.05). Replication in the CBAB6F2 mouse strain showed significant improvements in pregnancy rates at days 8 and 18 but not in blastocyst development. No adverse effects were seen on gestational age, litter size or birthweight, or the reproductive capacity of offspring of IGF2 + U + P treated embryos. For embryos susceptible to detrimental effects ofin vitroculture, IGF2, uPA and plasminogen supplementation of culture media can improve pregnancy success, but the effect of treatment is dependent on the mouse strain.

Improved detection of mineral oil toxicity using an extended mouse embryo assay

PURPOSE

Successful in vitro fertilization (IVF) relies on sound laboratory methods and culture conditions which depend on sensitive quality control (QC) testing. This study aimed to improve the sensitivity of mouse embryo assays (MEA) for detection of mineral oil toxicity.

METHODS

Five experiments were conducted to study modifications of the standard mouse embryo assay (MEA) in order to improve sensitivity using clinical grade mineral oil with known peroxide concentrations. Assessment of blastocyst development at either 96 h or in an extended MEA (eMEA) to 144 h was tested in each experiment. In experiment 1, ability to detect peroxides in oil was compared in the MEA, eMEA, and cell number at 96 h. In experiment 2, serial dilutions of peroxide in oil were used along with time-lapse imaging to compare sensitivity of the morphokinetic MEA to the eMEA. Culture conditions that may affect assay sensitivity were assessed in experiments 3-5, which examined the effect of group versus individual culture, oxygen concentration, and protein supplementation.

RESULTS

Extended MEA and cell counts identified toxicity not detected by the routine endpoint of blastocyst rate at 96 h. The eMEA was fourfold more sensitive than the standard MEA, and this sensitivity was similar to the morphokinetic MEA. Group culture had a protective effect against toxicity, while oxygen concentration did not affect blastocyst development. Protein supplementation with HSA had a protective effect on blastocyst development in eMEA.

CONCLUSIONS

The standard MEA used by manufacturers does not detect potentially lethal toxicity of peroxides in mineral oil. While group culture may mask toxicity, protein supplementation and oxygen concentration have minimal effect on assay sensitivity. The eMEA and time-lapse morphokinetic assessment are equally effective in detection of peroxide toxicity and thus provide manufacturers and end-users a simple process modification that can be readily adopted into an existing QC program.

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.

Effects of group culture on the development of discarded human embryos and the construction of human embryonic stem cell lines

PURPOSE

To explore the effect of group culture on the developmental potential of discarded embryos in in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) cycles and establish the human embryonic stem cell lines for future research.

METHORDS

Fresh discarded embryos were collected from the IVF/ICSI-ET program in the reproductive medical center of the first affiliated hospital of Zhengzhou university in this study. All zygotes were individually cultured from Day 1 to Day 3. On Day 3, discard embryos were then cultured in group of 1-4 embryos per droplet (30 μl/droplets) with a constant culture medium until Day 5 or 6. Mechanical method was used to isolate the inner cell mass (ICM) of blastocyst from the embryo. Then we inoculated the ICM on feeder layer. After identification of those cells, the human embryonic stem cell lines (hESCs) were established.

RESULTS

In this study, we collected 1,223 fresh discarded embryos and they were sequential cultured to the blastocysts (18.07 %, 221/1,223), in which good quality blastocysts were 61(4.98 %, 61/1,223). There was no significant difference in the patients. The embryos from 1PN, 2PN, 3PN were sequential cultured to the blastocyst s(39.31 %,92/234;12.87 %,64/497;13.21 %,65/492),in which good quality blastocysts was 13.6 %(32/92),2.61 %(13/64), 3.04 %(15/65).1PN embryo's blastulation rate and quality embryo formation rate was significantly higher than the 2PN and 3PN embryos' (P <0.05). Three embryos group cultivation has the highest blastulation rate and quality embryo formation rate (P <0.05). In total, we successfully established 4 hESCs lines.

CONCLUSION

The group culture of human discard embryos can improve the blastulation rate and blastocyst quality to some extent. Three embryos group cultivate is the better culture number. Human discard embryos are good source for establishment of hESCs.

Thinking big by thinking small: application of microfluidic technology to improve ART

In Vitro Fertilization (IVF) laboratories often carry a penchant to resist change while in the pursuit of maintaining consistency in laboratory conditions. However, implementation of new technology is often critical to expand scientific discoveries and to improve upon prior successes to advance the field. Microfluidic platforms represent a technology that has the potential to revolutionize the fundamental processes of IVF. While the focus of microfluidic application in IVF has centered on embryo culture, the innovative platforms carry tremendous potential to improve other procedural steps and represents a possible paradigm shift in how we handle gametes and embryos. The following review will highlight application of various microfluidic platforms in IVF for use in maturation, manipulation, culture, cryopreservation and non-invasive quality assessment; pointing out new insights gained into functions of sperm, oocytes and embryos. Platform design and function will also be discussed, focusing on limitations, advancements and future refinements that can further aid in their clinical implementation.

Influence of group embryo culture strategies on the blastocyst development and pregnancy outcome

PURPOSE

To compare two different embryo culture methods and to determine whether grouping embryos based on quality following Day 3 improved outcomes.

METHODS

Two group embryo culture methods were compared in this study. All zygotes were individually cultured from Day 1 to Day 3. On Day 3, embryos were then cultured in group of 2-5 embryos per droplet until Day 5 or 6. The two group culture methods are: A, embryos were randomly grouped regardless of embryo quality; B, good and poor quality embryos were separately grouped. Blastocyst development rate, blastocyst utilization rate, implantation rate and pregnancy rate were detected.

RESULTS

The group culture of Day 3 embryos, in which good or poor quality embryos were separately grouped, significantly promoted blastocyst development (61.2 %, 289/472) and blastocyst utilization rate (55.9 %, 264/472) in comparison with those embryos that were randomly grouped for culture regardless of embryo quality (44 %, 177/402 and 41.5 %, 167/402). There was no significant difference in the implantation rate and pregnancy rate between two group culture methods.

CONCLUSIONS

Grouping of embryos after Day 3 based on embryo quality may benefit blastocyst formation. This may be due to secretion of beneficial factors by good embryos, or removal of detrimental factors from poor embryos. No impacts on pregnancy or implantation outcomes were observed.

Rethinking in vitro embryo culture: new developments in culture platforms and potential to improve assisted reproductive technologies

The preponderance of research toward improving embryo development in vitro has focused on manipulation of the chemical soluble environment, including altering basic salt composition, energy substrate concentration, amino acid makeup, and the effect of various growth factors or addition or subtraction of other supplements. In contrast, relatively little work has been done examining the physical requirements of preimplantation embryos and the role culture platforms or devices can play in influencing embryo development within the laboratory. The goal of this review is not to reevaluate the soluble composition of past and current embryo culture media, but rather to consider how other controlled and precise factors such as time, space, mechanical interactions, gradient diffusions, cell movement, and surface interactions might influence embryo development. Novel culture platforms are being developed as a result of interdisciplinary collaborations between biologists and biomedical, material, chemical, and mechanical engineers. These approaches are looking beyond the soluble media composition and examining issues such as media volume and embryo spacing. Furthermore, methods that permit precise and regulated dynamic embryo culture with fluid flow and embryo movement are now available, and novel culture surfaces are being developed and tested. While several factors remain to be investigated to optimize the efficiency of embryo production, manipulation of the embryo culture microenvironment through novel devices and platforms may offer a pathway toward improving embryo development within the laboratory of the future.