In Vivo and In Vitro Models to Study Liver Fibrosis: Mechanisms and Limitations

Antioxidative Hyaluronic Acid–Bilirubin Nanomedicine Targeting Activated Hepatic Stellate Cells for Anti-Hepatic-Fibrosis Therapy

“…The primary driver of excessive ECM accumulation in patients with liver fibrosis is HSC activation, and one of the key factors responsible for activating HSCs is TGF-β . TGF-β-activated LX-2 cells are a widely used in vitro model for analyzing liver fibrosis. − We assessed the intracellular ROS production in TGF-β-activated LX-2 cells and the antioxidant activity of HABNs against intracellular ROS. We found that the intracellular 2′,7′-dichlorofluorescein fluorescence in TGF-β-activated LX-2 cells was much stronger than the fluorescence signal in quiescent LX-2 cells, indicating that LX-2 cells activated by TGF-β produced more intracellular ROS than quiescent LX-2 cells (Figure b).…”

“…A murine nonalcoholic steatohepatitis (NASH) model, in which the mice were fed a choline-deficient l -amino acid-defined high-fat diet (CD-HFD), serves as a dietary NASH model with rapidly progressive liver fibrosis. These CD-HFD-fed mice are considered to be a human-relevant NASH-fibrosis model. , Thus, to determine whether HABNs target fibrotic liver cells, especially activated HSCs, in vivo , we intravenously administered PEG-BN–Cy5.5 or HABN–Cy5.5 to mice fed either a CD-HFD or a normal diet (Figure a and Supplementary Figure 7). In mice fed a normal diet, most of the fluorescence signal from HABN–Cy5.5 was localized in the kidney, and minimal signal was observed in the normal liver (Figure b,c).…”

The Material World of 3D‐Bioprinted and Microfluidic‐Chip Models of Human Liver Fibrosis

“…The limited life span also prevents the execution of long-term studies of antifibrotic drugs evaluation. [34] HSC cell lines are a viable alternative, but some cell lines are already in a fully activated state, preventing the study of fibrosis induction and progression. [13] When cells are not differentiated into myofibroblasts yet, fibrosis may be induced by incubation with TGF-𝛽, a potent fibrogenic factor.…”

“…Animals have been the gold standard for liver disease modeling due to the possibility of studying body responses and integration of the different systems in the organism, which is particularly relevant given the crucial role of hepatic function for homeostasis. [29,34] However, the complexity of using a whole organism hinders results interpretation. Contrarily, the properties of in vitro models can be precisely tuned to replicate the disease and, more important, can be independently controlled, allowing a better study of the disease mechanisms and drug response.…”

“…However, this methodology does not mimic the progressive and chronic liver injury observed in humans. [34] Moreover, the pathophysiology of liver injury, the hepatic metabolism and the immune responses vary significantly between animals and humans. When selecting a disease induction method, it is crucial to consider the underlying research question and identify the essential human disease features that need to be replicated in the model.…”