In vitro models for liver toxicity testing

Abstract

Over the years, various liver-derived in vitro model systems have been developed to enable investigation of the potential adverse effects of chemicals and drugs. Liver tissue slices, isolated microsomes, perfused liver, immortalized cell lines, and primary hepatocytes have been used extensively. Immortalized cell lines and primary isolated liver cells are currently most widely used in vitro models for liver toxicity testing. Limited throughput, loss of viability, and decreases in liver-specific functionality and gene expression are common shortcomings of these models. Recent developments in the field of in vitro hepatotoxicity include three-dimensional tissue constructs and bioartificial livers, co-cultures of various cell types with hepatocytes, and differentiation of stem cells into hepatic lineage-like cells. In an attempt to provide a more physiological environment for cultured liver cells, some of the novel cell culture systems incorporate fluid flow, micro-circulation, and other forms of organotypic microenvironments. Co-cultures aim to preserve liver-specific morphology and functionality beyond those provided by cultures of pure parenchymal cells. Stem cells, both embryonic- and adult tissue-derived, may provide a limitless supply of hepatocytes from multiple individuals to improve reproducibility and enable testing of the individual-specific toxicity. This review describes various traditional and novel in vitro liver models and provides a perspective on the challenges and opportunities afforded by each individual test system.

An Automated Multiplexed Hepatotoxicity and CYP Induction Assay Using HepaRG Cells in 2D and 3D

“…6 3D spheroids have shown drug responses more similar to those of an in vivo model than the traditional two-dimensional (2D) cell culture, in both cancer therapeutic efficacy [7][8][9] and hepatotoxicity. [10][11][12][13][14] This is particularly important for limited cell models, such as primary human hepatocytes cultured in a 2D monolayer. Hepatocytes in monolayer cell culture rapidly dedifferentiate 15 and lose their morphology and functions, such as Phase I and II enzyme expression and albumin production.…”

Long-Term Coculture Strategies for Primary Hepatocytes and Liver Sinusoidal Endothelial Cells

“…[5][6][7][8][9][10] Primary hepatocytes are relatively easy to isolate and retain most of the important in vivo functions for several days in monolayer static culture, [11][12][13] and up to 2 weeks or longer when cocultured with stromal cell support, [14][15][16] under collagen gel or on micropatterned surfaces, [15][16][17] and continue to be the most studied for drug screening purposes in various formats. 9,10,18 A major advance in primary hepatocyte culture is the use of a collagen gel sandwich, wherein primary hepatocytes are cultured between two layers of type I collagen gel for extended time periods. 11,13 However, this method still lacks the contribution of non-parenchymal cells (NPCs) and the importance of the drug response of NPCs in addition to hepatocytes is being slowly realized.…”

Chip-based liver equivalents for toxicity testing – organotypicalness versus cost-efficient high throughput

“…18,41 Due to their tumorous nature they differ from primary human hepatocytes in various aspects. Therefore, primary human hepatocytes are thought of as the gold-standard for in vitro drug metabolism, enzyme induction and toxicity studies.…”

“…Therefore, primary human hepatocytes are thought of as the gold-standard for in vitro drug metabolism, enzyme induction and toxicity studies. 18 An impressive indicator for their functional superiority is their performance in bioartificial liver assist systems (BALS) successfully bridging the gap for intoxicated liver-failure patients until a transplantation. 42,43 Use of primary hepatocytes combined with a change of cell culture format to 3D and, more importantly, co-cultivation with non-parenchymal liver cells, such as endothelial cells, hepatic stellate cells or Kupffer cells, might improve their cellular and metabolic functions towards in vivo-like levels.…”

“…42,43 Use of primary hepatocytes combined with a change of cell culture format to 3D and, more importantly, co-cultivation with non-parenchymal liver cells, such as endothelial cells, hepatic stellate cells or Kupffer cells, might improve their cellular and metabolic functions towards in vivo-like levels. 22,18,44,45 Induced stem cell technologies, recently awarded with the Nobel Prize in Medicine, [46][47][48][49] might provide new solutions to the well described but restricted access to human liver tissue. 50,51 Random dynamic monocultures A number of microfluidic liver culture devices exposing hepatocytes in random 3D culture at a lower organisational level have been engineered and will be discussed in this section.…”