Recent advances in the isolation of liver cells

The liver consists of two types of epithelial cells: hepatocytes, which represent 60% to 70% of the liver cell population (l), or 90% of total liver mass (2); and intrahepatic bile duct epithelial cells, or cholangiocytes, which make up 2% to 3% of the liver cell population (3-5).Other liver cells include SCs, KCs, FSCs, pit cells, myofibroblasts and other endogenous liver cells (e.g., vascular and lymphatic endothelial cells, dendritic cells), which together account for 25% to 40% of the total hepatic cell population, or 10% of liver mass (1) (Table 1).For study of the precise functions of various liver cells, isolation techniques are required that provide a sufficient number of cells with a high degree of purity and viability.Justified concerns about the use of isolated cells include (a) the isolation process may alter plasma membrane components, (b) normal cellular functions that require attachment to basement membrane components or cooperative interactions between adjacent cells are lost during cell isolation and (c) isolated cells may exhibit responses that are altered compared with their normal in situ functions.Despite these concerns, studies of isolated cells have considerably expanded our knowledge of the biology of individual liver cells in ways not possible with the intact organ (5-17).Our purpose here is to present an overview of recent advances in the isolation of the distinct cell types found in the liver and to provide technical detail sufficient to permit the experimental hepatologist to select the optimal experimental approach for the purification and characterization of specific liver cells.The first part