Academic literature on the topic 'Vitrolite Division'

This project aimed to compare the three most popular commercial oocyte vitrification techniques to determine their suitability for the vitrification of felid germlines in rescue and conservation programs. The present study aimed to determine the viability and developmental competence of feline oocytes after IVM and vitrification using a commercial vitrification method. In the first experiment, oocytes were vitrified after in vitro maturation (IVM) using the Kitazato, Cryotech, and Vitrolife methods. The oocytes were stained with fluorescein diacetate and ethidium bromide to evaluate their viability. The differences between Vitrolife and the control, Cryotech and Kitazato were statistically significant (p < 0.05), and between the control and Kitazato, were highly significant (p < 0.01). There were no significant differences between the control and Cryotech, Vitrolife and Cryotech, or Kitazato and Vitrolife. In the second part of the experiment, oocytes, after IVM and vitrification using three commercial methods, were subjected to fertilization. After vitrification, IVF was performed. We observed 35% of embryonic divisions in the group where Vitrolife and Kitazato media were used and 45% in the control group. In the presented experiment, vitrification with Vitrolife media gave slightly better results for survival and fertilization, while in the case of emergency protocol vitrification, all of the above methods may be useful to protect material derived from valuable wild felids.

Abstract STUDY QUESTION Do embryos from sibling oocytes assigned to distinct single-step media culture systems demonstrate differences in early embryo development, morphokinectics or aneuploidy rates? SUMMARY ANSWER Embryo quality, morphokinetic parameters and aneuploidy rates from trophectoderm biopsy were similar between sibling embryos cultured in distinct media systems from the time of gamete isolation. WHAT IS KNOWN ALREADY Studies on the effect of commercially available embryo culture media systems have demonstrated inconsistent impact on human embryonic development, morphokinetics, aneuploidy rates and clinical outcomes. In addition, these studies have been primarily randomized at the level of the embryo or the patient to culture media. STUDY DESIGN, SIZE, DURATION Prospective sibling oocyte cohort derived from 200 subjects undergoing IVF at a tertiary academic medical center between February 2018 and November 2019. PARTICIPANTS/MATERIALS, SETTING, METHODS Sibling oocytes were allocated to Global® or SAGE® media system based upon laterality of ovary from which they were retrieved. All embryos were cultured in a time-lapse incubator. Blastocysts underwent trophectoderm biopsy for preimplantation genetic testing for aneuploidy using next-generation sequencing. MAIN RESULTS AND THE ROLE OF CHANCE One hundred twenty-seven subjects (n = 127) had paired blastocysts for biopsy in each culture media system. There was no difference in top quality blastocyst formation (47.1 ± 31.0 vs 48.1 ± 27.2%; P = 0.87) nor aneuploidy rate (62.3 ± 34.0 vs 56.1 ± 34.4%; P = 0.07) for sibling embryos cultured in Global versus SAGE media system. Embryo morphokinetic parameters including time to each cell division from two cells (t2) to eight cells (t8), time to morula stage (tM), time to blastocele formation (tSB), time to fully formed blastocyst (tB) and time to expansion of the blastocyst (tEB) were similar between paired blastocysts from each culture media system. LIMITATIONS, REASONS FOR CAUTION Pregnancy outcomes and offspring health data were not available for analysis. WIDER IMPLICATIONS OF THE FINDINGS Commercially available culture media may not have a differential impact on embryo development and blastocyst aneuploidy rate when patient and stimulation-related factors are held constant. STUDY FUNDING/COMPETING INTEREST(s) There was no external funding for this study. C.H. is owner of a consultancy company, IVF Professionals, Chief Scientific Officer at Apricity, Executive Director at TMRW and co-owner and shareholder of Aria Fertility. She has received speaker fees, consulting fees and travel support from Cooper Surgical and Vitrolife. J.B. is an employee and shareholder of vitrolife. TRIAL REGISTRATION NUMBER N/A.

Previous studies have suggested that aneuploidy rates are co-related with cell asymmetry at the cleavage stage. A retrospective study was carried out to determine the significance of blastomere symmetry at the 4-cell stage on blastocyst grade and ploidy status. 732 Day 5/6 blastocysts from 191 patients undergoing Pre-implantation Genetic Testing for Aneuploidy were analysed with time-lapse imaging (Embryoscope, Vitrolife) during 2017. Blastomere symmetry was measured at the first image of 4-cells on Day 2 by tabulating the mean diameter of 2 lines drawn perpendicularly on each blastomere. Symmetry was defined as the blastomere diameter difference of [Formula: see text] 25%. Trophectoderm (TE) biopsy was performed on Day 5/6 followed by chromosomal evaluation using Next Generation Sequencing (VeriSeq Protocol, Illumina). Blastocyst grade was classified as either “Good” (inner cell mass (ICM) and TE, AA respectively), “Fair/Good” (AB, BA), “Fair” (BB) and “Poor” (early blastocyst grade 2 or TE grading of C). The significance of blastomere symmetry on blastocyst grade and ploidy status was measured using chi-square tests. There was no significance difference in resulting blastocyst quality for symmetrical and asymmetrical embryos (Table 1: p [Formula: see text] 0.10). Furthermore, there was no significance difference in the euploid rate (42.5% vs. 45.3%) or mosaic rate (22.1% vs. 16.2%) between symmetrical and asymmetrical embryos (p [Formula: see text] 0.24). In conclusion, the presence of asymmetrical blastomeres at the 4-cell stage do not impact the good quality blastocyst formation rate and euploidy rate for embryos that progress into blastocysts. However, this study excludes embryos that do not develop to the blastocyst stage and those with erratic division patterns, direct cleavage and reverse cleavage on Day 2, both of which have potential to influence ploidy result. Asymmetrical 4-cell embryos have the potential for high quality euploid blastocyst progression and can be considered for day 2 embryo transfer in the absence of symmetrical 4-cell embryos.

Objetivos. Estudiar los patrones de contracciones en blastocistos humanos mediante el uso de una incubadora time-lapse y correlacionarlos con su estado de ploidía por análisis PGT-A, el tiempo para alcanzar el estado blastocisto, la tasa de implantación y de embarazo clínico. Diseño. Estudio de cohortes retrospectivo. Intervenciones. Entre octubre 2016 y mayo 2018, se evaluó 270 pacientes; se hizo cultivo extendido de 5 a 6 días a 912 embriones en la incubadora time-lapse (Embryoscope, Vitrolife), y a 778 se les estudió para aneuploidía usando una plataforma NGS en un laboratorio de referencia. Hubo posterior vitrificación, según resultado del desarrollo embrionario y en espera del resultado del NGS, seguido de desvitrificación y transferencia de embrión único. Se determinó las contracciones del blastocisto (CTB) mediante la herramienta de dibujo del embrión EmbryoViewer (EmbryoViewer drawing tools), de manera de obtener el área, porcentaje de contracción y los diferentes tipos de contracciones, y se comparó los embriones con el resultado del estudio genético mediante NGS. Se transfirió 182 embriones en pacientes de 30,4 años promedio, rango entre 24 y 39 años. Finalmente, se correlacionó la tasa de implantación y embarazo clínico de los embriones euploides que fueron transferidos, en el programa de reproducción asistida. Resultados. Se separó los embriones en dos grupos de acuerdo a las contracciones durante su desarrollo, en aquellos que las tuvieron (CT) y aquellos que no, denominados ‘solo expanding’ (SE). Los embriones SE fueron euploides en 58,3%, mientras los embriones CT fueron aneuploides en 53,6%, con significancia estadística (p=0,012). Ello indica que la mayoría de los embriones euploides hacen ‘solo expanding’ durante su desarrollo, mientras que la mayoría de los embriones aneuploides (53,9%) hacen contracciones durante su desarrollo (p=0,029). Del mismo modo, la tasa de embarazo clínico de los embriones SE euploides fue 63,1% frente a 46,7% de los embriones CT, p=0.012. Finalmente, los embriones euploides CT tardaron más en convertirse en blastocistos tempranos que los embriones SE, p=0.004. La edad de la mujer no representó un factor para contracción embrionaria. Conclusiones. Los resultados obtenidos en este estudio muestran que los embriones que muestran contracciones, sin importar que tan intensas sean, están relacionados con mayor probabilidad de aneuploidías, menor tasa de implantación y ritmos de división lentos. El simple hecho de observar contracciones en un embrión podría ser útil para decidir transferir otro embrión que no las haya tenido. Se requiere más estudios para comprobar estos hallazgos.

Oocyte vitrification enables the long-term conservation of female genetic resources. However, obtaining viable bovine embryos from vitrified oocytes has proven to be difficult. Embryo development is a dynamic process, and critical stages can go unnoticed with the use of traditional morphologic assessments. Therefore, the aim was to evaluate morphokinetic parameters in embryos derived from fresh versus vitrified oocytes. After 22h of IVM, oocytes were divided into (1) oocytes surrounded by multiple layers of cumulus cells (COCs; n=275) and (2) oocytes partially denuded, leaving only corona radiata (CR; n=178). Then, two-thirds of the CR oocytes were subjected to one of two vitrification protocols as follows: high concentration of cryoprotectants (CR-H; n=171; Ortiz-Escribano et al. 2016 Theriogenology 86, 635-641) and low concentration of cryoprotectants (CR-L; n=163; Ishii et al. 2018 J. Reprod. Develop. 6). After warming, vitrified oocytes were incubated ~2h in maturation medium. Invitro fertilization and culture were performed simultaneously for all groups. Four to eight zygotes from each group were assigned randomly to time lapse (Primo Vision; Vitrolife), and group culture was performed in leftovers as a control. Differences between groups in survival (intact zygotes after IVF), cleavage, and blastocyst rates were evaluated by logistic regression. Morphokinetic data (time to reach first (1-2 cells), second (3-4 cells), third (5-8), fourth (9-16 cells), fifth (&gt;16 cells), cleavage, and blastocyst stage, and time in lag phase) were investigated. Survival rates in COCs (98%) and CR (96%) groups were not different; CR-H (87%) showed lower survival than COCs but similar survival to that of CR. Group CR-L (82%) had a lower survival rate than the rest of the groups (P&lt;0.05). Higher cleavage rate (83%) was found in COCs compared with the rest of the groups. The CR and CR-H groups showed similar cleavage rate (65 and 55%, respectively), whereas CR-L had a lower cleavage rate (42%) than other groups (P&lt;0.05). As expected, both vitrified groups showed lower blastocyst rates (4% for CR-H and 10% for CR-L) than fresh COCs (44%; P&lt;0.05). Morphokinetics measures were affected by the treatments: time to reach first cleavage was similar for COCs (35.3h), CR (38.4h), and CR-L (34.8h), whereas CR-H was slower (42.4h). However, the fourth division was reached earlier by CR-H (51.7h), which was significantly faster than for CR-L (88.8 h; P&lt;0.05) but similar for COCs (71.3h) and CR (60.7h). In conclusion, more morphokinetic data are needed to compare different vitrification methods and confirm whether time-lapse analysis can be used to predict blastocyst outcome after oocyte vitrification.

Abstract Study question Is there a difference in irregular division kinetics between first and second division of human embryos? Summary answer The incidence of rapid cleavage was reduced in the second division, but the developmental potential of the blastomeres by this dynamics was unexpectedly low. What is known already The styles of irregular division of early human embryos are known: direct cleavage (DC), in which one cell becomes three (or more) cells without a two-cell phase, and rapid cleavage (RaC), in which one (or both) cells dividing rapidly after two-cell phase, both of which reduces the embryonic developmental potential. However, there are no reports that have examined in detail whether these division styles occur similarly in the first and second divisions, and how these dynamics affect the potential. Study design, size, duration This is a retrospective study of 635 embryos collected in 2020 at our clinic and cultured for at least 5 days. The embryos were time-lapse monitored by EmbryoScope (Vitrolife, Sweden) to observe the first and second divisions, and the blastomeres of each embryo were classified according to their style of division. Participants/materials, setting, methods It was observed whether there was a DC (division into 3 cells without a 2-cell phase) or RaC (One or two blastomeres divide within 5 hours after the 2-cell phase) at the first division. First dividing normal embryos were observed for the presence of a DC or RaC at the second division. Blastomeres by DC or RaC were observed for subsequent development and whether they participated in blastocysts or not was recorded. Main results and the role of chance Among the subject embryos, 63 embryos had DC and 199 embryos had RaC in the first division, and their blastomeres were classified into the DC1 and RaC1 groups, respectively. Of the 373 first division normal embryos, 39 had DC and 23 had RaC (there were 4 embryos with both DC and RaC) in the second division, and their blastomeres were classified into DC2 and RaC2 groups. The blastomeres blastocyst participation rate was 4.4% in the DC1 group and 19.5% in the RaC1 group, respectively, the former was significantly lower (P &lt; 0.01), however, in the DC2 and RaC2 groups, 23.3% and 4.2%, respectively, the latter was significantly lower (P &lt; 0.01). The incidence of DC was similar in the first (9.9%) and second (10.5%) divisions, but the incidence of RaC was 31.3% in the first division and 6.2% in the second division, the latter was significantly lower (P &lt; 0.01). The development rate of good blastocysts (≥4BC in Gardner grade) was 4.8% in embryos with DC1 and 19.5% in embryos with RaC1, with the former significantly lower (P &lt; 0.01), 37.0% in embryos with DC2, and 26.3% in embryos with RaC2, with no significant difference. Limitations, reasons for caution As of 2020, the clinical use of PGT-A is not approved in principle in Japan, and the subject embryos have not been chromosomally analyzed. Wider implications of the findings RaC would lead to inadequate DNA proliferation, but the incidence of this and the prognosis of the blastomeres were different in the first and second divisions. In human embryos, the mechanisms that control blastomeres from dividing may change as development progresses, but further studies are needed to elucidate this. Trial registration number not applicable

AbstractTo study the impact of culture media on preimplantation morphokinetics used for predicting clinical outcomes. All IVF and ICSI cycles performed between 2012 and 2017 with time-lapse information available were included. In November 2014, culture medium was changed from Vitrolife G-1 PLUS to SAGE 1-Step. Each embryo was retrospectively assigned a morphokinetic-based KIDScore for prediction of implantation. Clinical outcomes were retrieved from medical records. Linear mixed models were used to study differences in morphokinetic parameters, a proportional odds model for KIDScore ranking and logistic regression for differences in clinical outcomes. All analyses were adjusted for patient and treatment characteristics. In 253 (63.1%) cycles, embryos (n = 671) were cultured in Vitrolife, and in 148 (36.9%) cycles, embryos (n = 517) were cultured in SAGE. All cleavage divisions occurred earlier for SAGE embryos than for Vitrolife embryos (2-cell: -2.28 (95%CI: -3.66, -0.89), 3-cell: -2.34 (95%CI: -4.00, -0.64), 4-cell: -2.41 (95%CI: -4.11, -0.71), 5-cell: -2.54 (95%CI: -4.90, -0.18), 6-cell: -3.58 (95%CI: -6.08, -1.08), 7-cell: -5.62 (95%CI: -8.80, -2.45) and 8-cell: -5.32 (95%CI: -9.21, -1.42) hours, respectively). Significantly more embryos cultured in SAGE classified for the highest KIDScore compared to embryos cultured in Vitrolife (p < 0.001). No differences were observed in clinical outcomes. Our results demonstrate an impact of culture medium on preimplantation embryo developmental kinetics, which affects classification within the KIDScore algorithm, while pregnancy outcomes were comparable between the groups. This study underscores the need to include the type of culture medium in the development of morphokinetic-based embryo selection tools.

Summary To investigate the effects of culture media with different lactate concentrations on early embryonic development, data collected from our patients undergoing preimplantation genetic testing (PGT) were assessed using the EmbryoScope™ time-lapse culturing system. After intracytoplasmic sperm injection (ICSI), sibling oocytes were cultured in the same EmbryoScope (Vitrolife) slides including two different commercially available media. The patients with fewer than five mature oocytes were not included in the analyses. All embryos were hatched on day 3, and trophectoderm biopsies (n = 212) were performed accordingly. PGT for aneuploidy (PGT-A) on biopsied materials was carried out using next generation sequencing. Morphokinetic parameters, fertilization, irregular division, degeneration, blastulation, euploidy, and pregnancy rates of embryos cultured in LifeGlobal Global Total medium (LGGT) and Continuous Single Culture-NX Complete medium (CSCM-NXC) were compared. There were no differences observed in time to pronuclear fade, or in time spent as 2-cell (cc2) and 3-cell (s2), to 4-cell, 5-cell, morula and blastocyst stages (P > 0.05). Embryos reached the 2-cell (t2) and 3-cell (t3) stages significantly faster in LGGT (P < 0.05), whereas embryos grown in CSCM-NXC with lower lactate reached starting blastulation significantly sooner (P = 0.026). However, there were no statistical differences observed in fertilization, blastulation, degeneration, irregular division euploidy, and pregnancy rates between the two groups (P > 0.05). Even though pregnancy and fertilization rates did not indicate statistical differences, results are significant to provide better insight on potential roles of lactate in embryo development. These finding will advance the fundamental knowledge of human embryo development and assisted reproductive technologies.

Abstract Study question Direct cleavage (DC) and Rapid cleavage (RaC) both appear to be 1 cell divided into 3 (or more) cells, should they be distinguished? Summary answer Since blastomeres by RaC had higher developmental potential than blastomeres by DC, and since many RaC embryos had “normal” blastomere, the two should be distinguished. What is known already DC, in which one cell divides into three (or more) cells without the two-cell stage, and RaC, in which one or two cells divide rapidly after the short two-cell stage (The former lead to segregation of chromosomes into three cells, while the latter leads to inadequate DNA replication), are both often recorded as “DC”, but when classified in detail, there are reports that the blastocyst development rate is higher in RaC embryos. However, the reason for this has not been clarified. Study design, size, duration This was a retrospective study of 643 embryos collected and cultured for at least 5 days in 2020 at our clinic. The embryos were time-lapse monitored by EmbryoScope (Vitrolife, Sweden) and classified into three groups according to the style of first division. Participants/materials, setting, methods The embryos were classified as follows: DC group: embryos that have divided into three (or more) cells without a two-cell stage; RaC group: embryos that rapidly (&lt;5 hours) divided one (or both) cells after the 2-cell stage; Normal cleavage (NC) group: embryos that had a 2-cell stage for more than 5 hours. The subsequent development of blastomeres of all embryos was observed and whether they participated in blastocysts or not was recorded. Main results and the role of chance Of the embryos, 63 were in the DC group and 199 were in the RaC group (173 of which had one rapidly dividing blastomere and 26 of which had two). The blastocyst participation rate of blastomeres was 4.4% in the DC group, 19.5% of rapidly dividing blastomeres and 61.6% of normal blastomeres in the RaC group, with significant differences between all groups (p &lt; 0.01). The good blastocyst (4BC or higher in Gardner grade) development rate was 4.8% (3/63) in the DC group, 40.5% (70/173) in the RaC group with one rapidly dividing blastomere (RaC1 group), 19.2% (5/26) in the RaC group with two such blastomeres (RaC2 group), showing a significant difference between the DC and RaC1 groups (P &lt; 0.01). The live birth rate for single blastocyst transfer was 50% (1/2) in the DC group, 27.8% (5/18) in the RaC1 group, and 100% (1/1) in the RaC2 group. (Note that there were 381 in the NC group, and the above rates were 76.5%, 63.3% (241/381), and 29.3% (22/75), respectively) Limitations, reasons for caution This study examined only the style of first division and did not consider second and subsequent divisions. In addition, as of 2020, the clinical use of PGT-A is not approved in principle in Japan, and the subject embryos have not undergone chromosome analysis. Wider implications of the findings The reason for the higher blastocyst development rate in RaC embryos was indicated by the difference in blastocyst participation rates of the respective blastomeres and the presence of normal blastomeres, but since live births were obtained in both embryos, so these irregular divisions would not completely compromise the blastocyst euploidy. Trial registration number not applicable

Abstract Study question How much delay in the appearance of 2PN can be considered normal when predicting embryo transfer potential? Summary answer Embryos with tPNa &lt;13hpi post-insemination develop into good-quality blastocysts; embryos with tPNa ≥13hpi develop blastocysts by shortening the time of tPNf-tPNa. What is known already Oocytes generally exhibit 2PNs at 17–20 hours, with pronuclei fading (time of pronuclei fading; tPNf) at 23–25 hours and developing into two cells (time of 2-cell division; t2) at 25–33 hours. Fertilization confirmation is typically performed 17–18 hours after insemination. However, a few oocytes with no visible PN (0PN) at the time of fertilization confirmation develop morphologically normal blastocysts, ultimately leading to pregnancy. The failure to identify PNs can be attributed to two scenarios: rapid fading or delayed appearance. Notably, there is still a lack of research on the normal range for delayed PN appearance. Study design, size, duration This study was conducted with 2153 embryos obtained from 390 intracytoplasmic sperm injection cycles (August 2021 to June 2023). All embryos were incubated for 5 days using a time-lapse system (EmbryoScopeTM+, Vitrolife). The blastocyst development rate and morphokinetic parameters according to the tPNa of embryos were analyzed using KIDScore D5 v3 and iDAScore v2.0 (VTH server+, Vitrolife). Clinical pregnancy was also analyzed. Participants/materials, setting, methods Morphokinetic parameters were analyzed from time of second polar body (tPB2) ∼ time of expanded blastocyst (tEB). The times taken for PN to appear after the second polar body release (tPNa–tPB2), for PN to fade (tPNf–tPNa) and for 2-cell division (t2–tPNf) were calculated and compared. Blastocysts were graded using the Gardner system, a grade of BB or higher divided into good quality blastocysts (GQ-BL). Main results and the role of chance tPNa was observed as 8.09±2.11hpi [1.93hpi∼32.46hpi; &lt;5hpi (n = 49), 5∼6hpi (n = 474), 7∼8hpi (n = 1220), 9∼10hpi (n = 266), 11∼12hpi (n = 91), 13∼14hpi (n = 29), 15∼20hpi (n = 18) and &gt;20hpi (n = 6)]. The rate of blastocysts was highest at 5∼6hpi (64.98%) and significantly lower at 9∼10hpi (54.14%), 11∼12hpi (42.86%) and 13∼14hpi (31.03%) (p &lt; 0.005). Similarly, the rate of GQ-BL was also highest at 5∼6hpi (29.11%) and significantly lower at 9∼10hpi (19.17%), 11∼12hpi (10.99%) and 13∼14hpi (3.45%) (p &lt; 0.005). No embryos developed into GQ-BL at 15∼20hpi, and no embryos developed into blastocysts at &gt; 20hpi. The iDAScore was significantly different at &lt; 13hpi and ≥13hpi (6.00±1.86 vs. 4.24±2.26, p &lt; 0.005). Similarly, KIDScore D5 showed the same patterns (6.33±1.93 vs. 4.05±1.66, p &lt; 0.005). At ≥ 13hpi, no blastocysts led to pregnancy. Morphokinetic parameters were analyzed to identify the factors influencing the development of blastocysts. The analysis revealed that tPNf-tPNa tended to gradually become shorter with delayed tPNa. Notably, there were significant differences in tPNf-tPNa between &lt;13hpi and ≥13hpi (16.37±4.10 vs. 13.72±6.28, p &lt; 0.005). At ≥ 13hpi, tPNf-tPNa was shorter in blastocysts than in cases of cleavage arrest (10.68±5.74 vs. 15.28±5.97, p &lt; 0.05). It was particularly observed that tPNf-tPNa of GQ-BL in ≥ 13hpi was 7.90hpi, and t2 was not significantly different from blastocysts and GQ-BL in &lt; 13hpi (25.06 vs. 25.66±3.18 vs. 25.19±2.97). Limitations, reasons for caution More data are needed for conclusive pregnancy results due to the small number of samples. Additionally, the maturation of oocytes had yet to be considered; further detailed studies related to oocyte maturity are needed. Wider implications of the findings Embryos with a tPNa of &lt; 13hpi develop into GQ-BL. Embryos with delayed tPNa tend to overcome this by shortening the tPNf-tPNa, resulting in develop into blastocysts. Predicting blastocyst development can be achieved by considering factors such as tPNa∼t2. This can aid in improving the selection of embryos for cleavage-stage ET. Trial registration number N/A