Obesity is linked to adipose tissue dysfunction, a dynamic endocrine organ. Two-dimensional cultures present technical hurdles hampering their ability to follow individual or cell groups for metabolic disease research. Three-dimensional type I collagen microgels with embedded adipocytes have not been thoroughly investigated to evaluate adipogenic maintenance as instrument for studying metabolic disorders. We aimed to develop a novel tunable Col-I microgel simulating the adipocyte microenvironment to maintain differentiated cells with only insulin as in vitro model for obesity research. Adipocytes were cultured and encapsulated in collagen microgels at different concentrations (2, 3 and 4 mg/mL). Collagen microgels at 3 and 4 mg/mL were more stable after 8 days of culture. However, cell viability and metabolic activity were maintained at 2 and 3 mg/mL, respectively. Cell morphology, lipid mobilization and adipogenic gene expression demonstrated the maintenance of adipocyte phenotype in an in vitro microenvironment. We demonstrated the adequate stability and biocompatibility of the collagen microgel at 3 mg/mL. Cell and molecular analysis confirmed that adipocyte phenotype is maintained over time in the absence of adipogenic factors. These findings will help better understand and open new avenues for research on adipocyte metabolism and obesity. Insight box In the context of adipose tissue dysfunction research, new struggles have arisen owing to the difficulty of cellular maintenance in 2D cultures. Herein, we sought a novel approach using a 3D type I collagen-based biomaterial to adipocyte culture with only insulin. This component was tailored as a microgel in different concentrations to support the growth and survival of adipocytes. We demonstrate that adipocyte phenotype is maintained and key adipogenesis regulators and markers are over time. The cumulative results unveil the practical advantage of this microgel platform as an in vitro model to study adipocyte dysfunction and obesity.

中文翻译：

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胶原微凝胶模拟脂肪细胞微环境，用于肥胖的体外研究。

肥胖与脂肪组织功能障碍有关，脂肪组织是一种动态内分泌器官。二维培养存在技术障碍，阻碍了它们跟踪个体或细胞群进行代谢疾病研究的能力。尚未对嵌入脂肪细胞的三维 I 型胶原微凝胶进行彻底研究，以评估脂肪生成维持作为研究代谢紊乱的工具。我们的目标是开发一种新型可调节 Col-I 微凝胶，模拟脂肪细胞微环境，仅用胰岛素维持分化细胞作为肥胖研究的体外模型。培养脂肪细胞并将其封装在不同浓度（2、3 和 4 mg/mL）的胶原微凝胶中。培养 8 天后，3 和 4 mg/mL 的胶原微凝胶更加稳定。然而，细胞活力和代谢活性分别维持在 2 和 3 mg/mL。细胞形态、脂质动员和脂肪形成基因表达证明了体外微环境中脂肪细胞表型的维持。我们证明了 3 mg/mL 的胶原微凝胶具有足够的稳定性和生物相容性。细胞和分子分析证实，在没有脂肪形成因子的情况下，脂肪细胞表型会随着时间的推移而得以维持。这些发现将有助于更好地理解脂肪细胞代谢和肥胖的研究并开辟新的途径。在脂肪组织功能障碍研究的背景下，由于二维培养物中细胞维持的困难，出现了新的难题。在此，我们寻求一种新方法，使用 3D I 型胶原蛋白生物材料仅用胰岛素进行脂肪细胞培养。该成分被定制为不同浓度的微凝胶，以支持脂肪细胞的生长和存活。我们证明，随着时间的推移，脂肪细胞表型得以维持，并且关键的脂肪生成调节剂和标记物得以维持。累积结果揭示了该微凝胶平台作为研究脂肪细胞功能障碍和肥胖的体外模型的实际优势。