Mass transfer and metabolic reactions in hepatocyte spheroids cultured in rotating wall gas-permeable membrane system
Mass transfer and metabolic reactions in hepatocyte spheroids cultured in rotating wall gas-permeable membrane system
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DOI：
10.1016/j.biomaterials.2007.08.033
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发表时间：
2007-12-01
期刊：
影响因子：
14
通讯作者：
Bader, Augustinus
中科院分区：
文献类型：
--
作者：
Curcio, Efrern;Salerno, Simona;Bader, Augustinus
分离的肝细胞在球状体构型中表现出高度的细胞-细胞接触，这对于维持活力和肝脏特异性功能是重要的。在缺乏血管网络的情况下，大球体尺寸中的细胞在聚集体的核心中经历代谢物和氧的传质限制。本文用数学方法描述了在不透气的聚苯乙烯壁系统（RWPS）和具有透氧膜的聚苯乙烯壁膜系统（RWMS）中培养的肝细胞球状体中氧、葡萄糖和乳酸的扩散和反应的转运现象，并进行了实验验证。葡萄糖，氧和乳酸在肝细胞球体的浓度分布估计为不同直径的聚集体通过求解同时扩散和反应的传质方程，通过有限元法。模拟结果表明，对于在RWPS和RWMS系统中培养的粒径小于300 μ m的团聚体，葡萄糖和乳酸的浓度分布朝向球体的核心（有效扩散系数在10（-11）m（2）/s的量级）不受代谢率的显著影响（c.对于葡萄糖为10（-6）μ g/mm（3）/s，对于乳酸盐约低一个数量级）。相反，氧的运输（扩散系数：3.4 × 10（-10）m（2）/s，反应速率：1.5 × 10（-5）μ g/mm（3）/s）受到多细胞球体大小的严重影响，并且在球体中可能产生显著的氧浓度梯度。粒径大于200 μ m的聚集体在其大部分尺寸中受到严重的氧限制，在中心达到最低的分压。通过实验证实了在RWMS中培养肝细胞球状体的模型预测的改善的活力，其特征在于相对于RWPS具有更高的O渗透性。结果表明，在这项研究中使用的数学模型代表了一个有用的支持实验程序，以获得最佳尺寸的肝细胞球体。(C)2007爱思唯尔有限公司保留所有权利。
Isolated hepatocytes in-spheroid configuration exhibit a high degree of cell-cell contacts, which are important in the maintenance of viability and liver specific functions. In the absence of a vascular network, the cells in a large spheroid size experience mass transfer limitations of metabolites and oxygen in the core of aggregates. In this paper transport phenomena related to the diffusion and reaction of oxygen, glucose and lactate are mathematically described and experimentally verified for hepatocyte spheroids cultured in a rotating-wall polystyrene system (RWPS) not permeable for gases and in a rotating-wall membrane system (RWMS) with oxygen-permeable membrane. The concentration profiles of glucose, oxygen and lactate in the hepatocyte spheroids were estimated for different diameters of aggregates by solving the mass transfer equations for simultaneous diffusion and reaction, by finite element method. Simulation results evidenced that, for aggregates with size lower than 300 mu m cultured in both RWPS and RWMS systems, the concentration profiles of glucose and lactate towards the core of spheroids (effective diffusion coefficients in the order of 10(-11) m(2)/s) are not significantly affected by the metabolic rate (c.a 10(-6) mu g/mm(3)/s for glucose and about one order of magnitude less for lactate). On the contrary, the transport of oxygen (diffusion coefficient: 3.4 x 10(-10) m(2)/s, reaction rate: 1.5 x 10(-5) mu g/mm(3)/s) is critically affected by the size of the multicellular spheroids and significant gradients in oxygen concentration may develop in spheroids. Aggregates with a size greater than 200 mu m suffer severe oxygen limitation in the most part of its size attaining the lowest partial pressure in the centre. The improved viability predicted by the model culturing hepatocyte spheroids in the RWMS, characterized by a higher O permeability with respect to RWPS, was experimentally confirmed. The results demonstrated that the mathematical model used in this study represents a useful support to experimental procedures in order to obtain hepatocyte spheroids with optimal size. (C) 2007 Elsevier Ltd. All rights reserved.