Human‐induced pluripotent stem cells (iPSCs) hold the promise to improve cell‐based therapies. Yet, to meet rising demands and become clinically impactful, sufficient high‐quality iPSCs in quantity must be generated, a task that exceeds current capabilities. In this study, K3 iPSCs cultures were examined using parallel‐labeling metabolic flux analysis (¹³C‐MFA) to quantify intracellular fluxes at relevant bioprocessing stages: glucose concentrations representative of initial media concentrations and high lactate concentrations representative of fed‐batch culture conditions, prior to and after bolus glucose feeds. The glucose and lactate concentrations are also representative of concentrations that might be encountered at different locations within 3D cell aggregates. Furthermore, a novel method was developed to allow the isotopic tracer [U‐¹³C₃] lactate to be used in the ¹³C‐MFA model. The results indicated that high extracellular lactate concentrations decreased glucose consumption and lactate production, while glucose concentrations alone did not affect rates of aerobic glycolysis. Moreover, for the high lactate cultures, lactate was used as a metabolic substrate to support oxidative mitochondrial metabolism. These results demonstrate that iPSCs have metabolic flexibility and possess the capacity to metabolize lactate to support exponential growth, and that high lactate concentrations alone do not adversely impact iPSC proliferation.

中文翻译：

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诱导多能干细胞可以利用乳酸作为代谢底物来支持增殖

人类诱导的多能干细胞 (iPSC) 有望改善基于细胞的疗法。然而，为了满足不断增长的需求并在临床上产生影响，必须产生足够数量的高质量 iPSC，这是一项超出当前能力的任务。在这项研究中，K3 iPSCs 培养物使用平行标记的代谢通量分析（¹³C-MFA）以量化相关生物加工阶段的细胞内通量：葡萄糖浓度代表初始培养基浓度和高乳酸浓度代表分批补料培养条件，在推注葡萄糖进料之前和之后。葡萄糖和乳酸浓度也代表了 3D 细胞聚集体中不同位置可能遇到的浓度。此外，还开发了一种新方法，使同位素示踪剂 [U- ¹³ C ₃ ] 乳酸可用于¹³C-MFA 模型。结果表明，高细胞外乳酸浓度降低了葡萄糖消耗和乳酸产生，而单独的葡萄糖浓度不影响有氧糖酵解的速率。此外，对于高乳酸培养物，乳酸被用作代谢底物以支持氧化线粒体代谢。这些结果表明，iPSCs 具有代谢灵活性并具有代谢乳酸以支持指数增长的能力，并且单独的高乳酸浓度不会对 iPSC 增殖产生不利影响。