Kermack Alexandra J, Fesenko Irina, Christensen David R, Parry Kate L, Lowen Philippa, Wellstead Susan J, Harris Scott F, Calder Philip C, Macklon Nicholas S, Houghton Franchesca D
Centre for Human Development, Stem Cells and Regeneration, School of Human Development and Health, Faculty of Medicine, University of Southampton, Southampton, UK.
NIHR Southampton Biomedical Research Centre, University Hospital Southampton NHS Foundation Trust and University of Southampton, Southampton, UK.
Hum Reprod. 2022 Nov 24;37(12):2757-2767. doi: 10.1093/humrep/deac233.
Does the type of incubator used to culture human preimplantation embryos affect development to the blastocyst stage and alter amino acid utilization of embryos in assisted reproduction?
Culturing embryos in a time lapse system (TLS) was associated with a higher Day 5 blastocyst formation rate and altered amino acid utilization when measured from Day 3 to Day 5 compared to the standard benchtop incubator.
Culture environment is known to be important for the developing preimplantation embryo. TLSs provide a stable milieu allowing embryos to be monitored in situ, whereas embryos cultured in standard benchtop incubators experience environmental fluctuations when removed for morphological assessment.
STUDY DESIGN, SIZE, DURATION: A prospective clinical trial randomizing 585 sibling embryos to either the TLS (289 embryos) or the standard benchtop incubator (296 embryos) over a 23-month period in a UK University Hospital Fertility Clinic.
PARTICIPANTS/MATERIALS, SETTING, METHODS: Participants were aged 42 years or under, had an antral follicle count of ≥12 and ≥6 2 pronucleate zygotes. Zygotes were cultured individually in 25 µl of medium. Randomized embryos were graded and selected for transfer or cryopreservation on Day 5. For those embryos produced by women who underwent stimulation with recombinant FSH injections and were triggered with hCG, spent medium was collected on Day 5 for amino acid analysis by high pressure liquid chromatography. Clinical pregnancy was defined as the presence of a foetal heart beat on ultrasound scan at 7 weeks.
Overall, blastocyst formation rate on Day 5 was significantly higher in embryos cultured in the TLS (55%) compared to the standard incubator (45%; P = 0.013). Similarly, there was an increase in the number of blastocysts suitable for cryopreservation in the TLS (31%) compared to the standard incubator (23%; P = 0.032). There was a significant difference in the utilization of 12 amino acids by blastocysts cultured from Day 3 to Day 5 in the TLS compared to the standard incubator. Embryos cultured in the TLS displayed an increased total amino acid utilization (P < 0.001) and reduced amino acid production (P < 0.001) compared to those in the standard incubator. Irrespective of incubator used, embryos fertilized by ICSI depleted significantly more amino acids from the medium compared to those fertilized by conventional IVF. There was no difference in the mean score of blastocysts transferred, or the clinical pregnancy rate after transfer of embryos from either of the incubators.
LIMITATIONS, REASONS FOR CAUTION: The study was not powered to discern significant effects on clinical outcomes.
The metabolism and development of preimplantation embryos is impacted by the type of incubator used for culture. Further research is required to investigate the long-term implications of these findings.
STUDY FUNDING/COMPETING INTEREST(S): NIHR Southampton Biomedical Research Centre Commercial and Enterprise Incubator Fund funded this study. The TLS was provided on loan for the study by Vitrolife. The authors declare no conflict of interests.
ISRCTN73037149.
12 January 2012.
DATE OF FIRST PATIENT’S ENROLMENT: 21 January 2012.
用于培养人类植入前胚胎的培养箱类型是否会影响其发育至囊胚阶段，并改变辅助生殖中胚胎的氨基酸利用情况？
与标准台式培养箱相比，在延时成像系统（TLS）中培养胚胎，第5天的囊胚形成率更高，且从第3天到第5天测量时氨基酸利用情况有所改变。
已知培养环境对发育中的植入前胚胎很重要。TLS提供了一个稳定的环境，使胚胎能够在原位进行监测，而在标准台式培养箱中培养的胚胎在取出进行形态学评估时会经历环境波动。
研究设计、规模、持续时间：一项前瞻性临床试验，在英国一家大学医院生育诊所的23个月期间，将585个同胞胚胎随机分为TLS组（289个胚胎）和标准台式培养箱组（296个胚胎）。
参与者/材料、环境、方法：参与者年龄在42岁及以下，窦卵泡计数≥12个，有≥6个双原核受精卵。受精卵在25微升培养基中单独培养。随机分组的胚胎在第5天进行分级，并选择用于移植或冷冻保存。对于那些接受重组促卵泡素注射刺激并用hCG触发的女性所产生的胚胎，在第5天收集用过的培养基，通过高压液相色谱法进行氨基酸分析。临床妊娠定义为在7周超声扫描时出现胎儿心跳。
总体而言，与标准培养箱（45%）相比，在TLS中培养的胚胎第5天的囊胚形成率显著更高（55%；P = 0.013）。同样，与标准培养箱（23%）相比，TLS中适合冷冻保存的囊胚数量有所增加（31%；P = 0.032）。与标准培养箱相比，从第3天到第5天在TLS中培养的囊胚对12种氨基酸的利用存在显著差异。与标准培养箱中的胚胎相比，在TLS中培养的胚胎总氨基酸利用率增加（P < 0.001），氨基酸产生减少（P < 0.001）。无论使用何种培养箱，通过卵胞浆内单精子注射受精的胚胎比通过传统体外受精受精的胚胎从培养基中消耗的氨基酸显著更多。移植的囊胚平均评分以及来自任一培养箱的胚胎移植后的临床妊娠率均无差异。
局限性、谨慎理由：该研究的样本量不足以辨别对临床结局的显著影响。
用于培养的培养箱类型会影响植入前胚胎的代谢和发育。需要进一步研究来调查这些发现的长期影响。
研究资金/利益冲突：英国国家卫生研究院南安普敦生物医学研究中心商业与企业孵化基金资助了本研究。TLS由Vitrolife公司提供用于本研究的借用设备。作者声明无利益冲突。
ISRCTN73037149。
2012年1月12日。
2012年1月21日。
