Advanced Solutions Life Sciences, 500 N Commercial St, Manchester, NH 03101, United States of America.
Biofabrication. 2021 Apr 7;13(3). doi: 10.1088/1758-5090/abe187.
Tissue organoids are proving valuable for modeling tissue health and disease in a variety of applications. This is due, in part, to the dynamic cell-cell interactions fostered within the 3D tissue-like space. To this end, the more that organoids recapitulate the different cell-cell interactions found in native tissue, such as that between parenchyma and the microvasculature, the better the fidelity of the model. The microvasculature, which is comprised of a spectrum of cell types, provides not only perfusion in its support of tissue health, but also important cellular interactions and biochemical dynamics important in tissue phenotype and function. Here, we incorporate whole, intact human microvessel fragments isolated from adipose tissue into organoids to form both mesenchymal stem cell (MSC) and adipocyte vascularized organoids. Isolated microvessels retain their native structure and cell composition, providing a more complete representation of the microvasculature within the organoids. Microvessels expanded via sprouting angiogenesis within organoids comprised of either MSCs or MSC-derived adipocytes grew out of the organoids when placed in a 3D collagen matrix. In MSC organoids, a ratio of 50 MSCs to 1 microvessel fragment created the optimal vascularization response. We developed a new differentiation protocol that enabled the differentiation of MSCs into adipocytes while simultaneously promoting microvessel angiogenesis. The adipocyte organoids contained vascular networks, were responsive in a lipolysis assay, and expressed the functional adipocyte markers adiponectin and peroxisome proliferator-activated receptor gamma. The presence of microvessels promoted insulin receptor expression by adipocytes and modified interleukin-6 secretion following a tumor necrosis factor alpha challenge. Overall, we demonstrate a robust method for vascularizing high cell-density organoids with potential implications for other tissues as well.
组织类器官在多种应用中被证明对模拟组织健康和疾病具有重要价值。这在一定程度上是由于 3D 组织样空间内促进了动态的细胞-细胞相互作用。为此，类器官越能重现天然组织中发现的不同细胞-细胞相互作用，如实质细胞和微血管之间的相互作用，模型的保真度就越高。微血管由一系列细胞类型组成，不仅为组织健康提供灌注，还提供重要的细胞相互作用和生化动力学，对组织表型和功能很重要。在这里，我们将从脂肪组织中分离出来的完整的、完整的人类微血管片段纳入类器官中，形成间充质干细胞 (MSC) 和脂肪细胞血管化类器官。分离的微血管保留其天然结构和细胞组成，为类器官内的微血管提供更完整的代表性。在由 MSC 或 MSC 衍生的脂肪细胞组成的类器官中，通过血管生成扩张的微血管在放入 3D 胶原基质时从类器官中生长出来。在 MSC 类器官中，MSC 与 1 个微血管片段的比例为 50:1 时，可产生最佳的血管化反应。我们开发了一种新的分化方案，使 MSCs 分化为脂肪细胞，同时促进微血管血管生成。脂肪细胞类器官包含血管网络，在脂肪分解测定中具有反应性，并表达功能性脂肪细胞标志物脂联素和过氧化物酶体增殖物激活受体γ。微血管的存在促进了脂肪细胞中胰岛素受体的表达，并修饰了肿瘤坏死因子 α 挑战后的白细胞介素 6 的分泌。总体而言，我们展示了一种强大的方法，可以使高细胞密度的类器官血管化，这可能对其他组织也有影响。
