Inventory of Artificial Liver Support based on the mixed culture system of Hepatocytes with Ito cells

细胞间相互作用在胚胎发生、成人生理和许多疾病过程的病理生理中都很重要。实质细胞和间充质细胞的共培养已被广泛应用于体外细胞间相互作用的研究。此外，两种细胞类型的共培养提供了用于治疗或研究应用的高功能组织结构。在这项研究中，我们利用微加工技术在刚性衬底上的图案配置中定位这两种细胞群。我们能够在大范围内控制单细胞型培养的同型相互作用水平和共培养的异型接触程度。我们的实验表明，星状细胞数量和增加的异质性细胞-细胞相互作用影响肝细胞功能。器官由许多不同类型的细胞组成，它们共同负责协调组织功能。我们可以在体外模拟肝脏功能，并利用该系统来阐明肝脏发育的基本因素。我们通过尿素合成和白蛋白分泌来监测肝脏的特异性功能，这些功能随着异源性细胞-细胞相互作用的增加而变化2倍。尿素是代谢功能的标志，白蛋白分泌是合成功能的标志。我们还研究了脂质代谢和P450酶解毒活性。所有数据表明，增加异质性细胞-细胞相互作用有助于维持肝脏特异性功能。此外，在该系统中共培养胚胎干细胞时，还能诱导胚胎干细胞中某些肝细胞特异性蛋白的表达。这些证据表明，这种方法将允许进一步阐明两种细胞类型之间的复杂相互作用，因为它们在体外形成功能模型组织或在体内相互作用形成功能器官。虽然需要进一步的研究来开发用于临床的人工肝，但本研究已经清楚地表明，适当的共培养方法比其他方法有更多的优势。少

Cell- cell interactions are important in embryogenesis, in adult physiology and pathophysiology of many disease processes. Co-cultivation of parenchymal and mesenchymal cells has been widely utilized as a paradigm for the study of cell-cell interactions in vitro. In addition, co-cultures of two cell types provide highly functional tissue constructs for use in therapeutic or investigational applications. In this study, we utilize micro fabrication techniques to localize both cell populations in patterned configulations on rigid substrates. We were able to control the level of homotypic interaction in cultures of single cell type and the degree of heterotypic contact in co-culture over a wide range. We have experimentally shown that stellate cells numbers and increased heterotipic cell-cell interactions influences hepatocellular functions. Organs are composed of many individual cell types and together responsible for orchestrating tissue functions. We could mimic liver function in vitro … More and utilize this sytem to elucidate fundamental factors of liver development. We monitored liver -specific functions by urea synthesis and albumin secretion, varied 2-fold with increasing heterotipic cell-cell interactions. Urea is a marker of metabolic function and albumin secretion is a marker of synthetic function. We also investigated lipid metabolism and P450 enzymatic detoxification activity. All data indicated that increasing heterotipic cell-cell interactions contributed maintaining liver specific functions. Moreover we could induced some hepatocyte specific protein expression in ES cells when we co-cultivate ES cells in this system. These evidence indicate that this approach will allow further elucidation of the complex interplay betweentwo cell types as they form a functional model tissue in vitro or as they interact in vivo to form functional organ. Although further investigations are necessary to develop artificial liver for clinical use, this study has clearly shown that appropriate co-clutivation method is numers of advantage over the other approaches. Less