STUDY QUESTION What is the composition of currently available commercial human embryo culture media provided by seven suppliers, for each stage of human preimplantation embryo development? SUMMARY ANSWER While common trends existed across brands, distinct differences in composition underlined the absence of a clear standard for human embryo culture medium formulation. WHAT IS KNOWN ALREADY The reluctance of manufacturers to fully disclose the composition of their human embryo culture media generates uncertainty regarding the culture conditions that are used for human preimplantation embryo culture. The critical role of the embryo culture environment is well-recognized, with proven effects on IVF success rates and child outcomes, such as birth weight. The lack of comprehensive composition details restricts research efforts crucial for enhancing our understanding of its impacts on these outcomes. The ongoing demand for greater transparency remains unmet, highlighting a significant barrier in embryo culture medium optimization. STUDY DESIGN, SIZE, DURATION For this study, 47 different human embryo culture media and protein supplements were purchased between December 2019 and June 2020; they comprise complete media (n = 23), unsupplemented media (n = 14), and supplements (n = 10). Unsupplemented media were supplemented with each available supplement from the same brand (n = 33 combinations). All samples were directly frozen in liquid nitrogen and stored at −80°C until composition analysis. PARTICIPANTS/MATERIALS, SETTING, METHODS We determined the concentrations of 40 components in all samples collected (n = 80). Seven electrolytes (calcium, chloride, iron, magnesium, phosphate, potassium, sodium), glucose, immunoglobulins A, G, and M (IgA, IgG, IgM), uric acid, alanine aminotransferase (ALAT), aspartate aminotransferase (ASAT), and albumin, as well as the total protein concentration, were determined in each sample using a Cobas 8000 Analyser (Roche Diagnostics). Analysis of pyruvate, lactate, carnitine, and 21 amino acids was achieved with Ultra-High Performance Liquid Chromatography-Mass Spectrometry (UPLC-MS/MS). MAIN RESULTS AND THE ROLE OF CHANCE Our analysis showed that generally, the concentrations of components of ready-to-use human embryo culture media align with established assumptions about the changing needs of an embryo during early development. For instance, glucose concentrations displayed a high-low-high pattern in sequential media systems from all brands: 2.5–3 mM in most fertilization media, 0.5 mM or below in all cleavage stage media, and 2.5–3.3 mM in most blastocyst stage media. Continuous media generally resembled glucose concentrations of cleavage stage media. However, for other components, such as lactate, glycine, and potassium, we observed clear differences in medium composition across different brands. No two embryo culture media compositions were the same. Remarkably, even embryo culture media from brands that belong to the same parent company differed in composition. Additionally, the scientific backing for the specific concentrations used and the differences in the composition of sequential media is quite limited and often based on minimal in vivo studies of limited sample size or studies using animal models. LARGE SCALE DATA N/A. LIMITATIONS, REASONS FOR CAUTION We used a targeted approach and performed a selection of tests which limit the composition analysis to this set of analytes. WIDER IMPLICATIONS OF THE FINDINGS Comprehensive disclosure and complete transparency concerning the composition of human embryo culture media, including the exact concentration of each component, are crucial for evidence-based improvements of culture media for human preimplantation embryos. STUDY FUNDING/COMPETING INTEREST(S) This research was supported by ZonMw (https://www.zonmw.nl/en), Programme Translational Research 2 (project number 446002003). M.G. declares an unrestricted research grant from Ferring not related to the presented work, paid to the institution VU Medical Center. The remaining authors have no conflicts of interest to declare. TRIAL REGISTRATION NUMBER N/A.

中文翻译：

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市售人胚胎培养基的组成


研究问题 七家供应商为人类植入前胚胎发育的每个阶段提供的目前可用的商业人类胚胎培养基的成分是什么？总结答案 虽然各个品牌之间存在共同的趋势，但成分的明显差异凸显了人类胚胎培养基配方缺乏明确的标准。已知的内容制造商不愿完全披露其人类胚胎培养基的成分，这给用于人类植入前胚胎培养的培养条件带来了不确定性。胚胎培养环境的关键作用已得到广泛认可，对 IVF 成功率和儿童结局（如出生体重）有明显影响。缺乏全面的组成细节限制了研究工作，这对于增强我们对其对这些结果的影响的理解至关重要。对更高透明度的持续需求仍未得到满足，这凸显了胚胎培养基优化方面的重大障碍。研究设计、规模、持续时间 对于这项研究，在 2019 年 12 月至 2020 年 6 月期间购买了 47 种不同的人类胚胎培养基和蛋白质补充剂;它们包括完全培养基 （n = 23）、未补充培养基 （n = 14） 和添加剂 （n = 10）。未添加的培养基补充了来自同一品牌的每种可用补充剂（n = 33 种组合）。所有样品均直接用液氮冷冻并储存在 −80°C 直至成分分析。参与者/材料、设置、方法 我们确定了收集的所有样品中 40 种成分的浓度 （n = 80）。 使用 Cobas 8000 分析仪 （Roche Diagnostics） 测定每个样品中的 7 种电解质（钙、氯化物、铁、镁、磷酸盐、钾、钠）、葡萄糖、免疫球蛋白 A、G 和 M（IgA、IgG、IgM）、尿酸、丙氨酸氨基转移酶 （ALAT）、天冬氨酸氨基转移酶 （ASAT） 和白蛋白，以及总蛋白浓度。使用超高效液相色谱-质谱 （UPLC-MS/MS） 分析丙酮酸、乳酸、肉碱和 21 种氨基酸。主要结果和机会的作用我们的分析表明，一般来说，即用型人类胚胎培养基的成分浓度与关于胚胎在早期发育过程中不断变化的需求的既定假设一致。例如，葡萄糖浓度在所有品牌的连续培养基系统中表现出高-低-高模式：大多数受精培养基中为 2.5-3 mM，所有卵裂期培养基中为 0.5 mM 或更低，大多数囊胚期培养基中为 2.5-3.3 mM。连续培养基通常类似于切割期培养基的葡萄糖浓度。然而，对于其他成分，如乳酸、甘氨酸和钾，我们观察到不同品牌的培养基成分存在明显差异。没有两种胚胎培养基成分是相同的。值得注意的是，即使是来自同一母公司品牌的胚胎培养基，其成分也有所不同。此外，所用特定浓度和连续培养基成分差异的科学依据非常有限，并且通常基于有限样本量的最小体内研究或使用动物模型的研究。大规模数据 N/A。 局限性，谨慎原因 我们使用了有针对性的方法，并进行了一系列测试，将成分分析限制在这组分析物中。研究结果的更广泛影响 关于人类胚胎培养基成分的全面披露和完全透明，包括每种成分的确切浓度，对于人类植入前胚胎培养基的循证改进至关重要。研究资金/利益争夺 这项研究得到了 ZonMw （https://www.zonmw.nl/en）、Programme Translational Research 2 （项目编号 446002003） 的支持。M.G. 宣布 Ferring 向 VU 医学中心支付了与所展示的工作无关的无限制研究资助。其余作者没有需要声明的利益冲突。试验注册号 N/A。