Objective:

To analyze the adverse outcome pathway (AOP) related to triclosan (TCS)-induced liver fibrosis and highlight the role of microbial dysbiosis in this process.

Approach:

• Analysis of AOP: The article reviews the roles of TGF-β1 and the AGEs-RAGE cascade in hepatic stellate cell activation, providing a mechanistic framework for understanding TCS-related liver hazards.
• Critique of Current Model: The authors argue that the current model overlooks TCS's role as an antimicrobial, leading to gut microbiome disruption and subsequent liver toxicity.

Key Findings:

• TCS exposure leads to microbial dysbiosis, compromising intestinal barrier integrity.
• Dysbiosis allows for increased portal delivery of lipopolysaccharide (LPS) to the liver.
• Kupffer cells respond to LPS by releasing pro-fibrogenic cytokines, particularly TGF-β1.
• Microbial dysbiosis and endotoxemia may be the actual initiating events driving hepatic TGF-β1 surge.

Interpretation:

The authors suggest that future AOP models could benefit from including the gut-liver axis for a more comprehensive understanding of TCS-induced liver fibrosis.

Limitations:

• The current AOP model does not account for the impact of the microbiome on liver toxicity.
• Exclusion of microbial factors creates a gap in environmental risk assessments for antibacterial agents.

Conclusion:

Incorporating the gut-liver axis into AOP models may enhance understanding of the mechanisms behind TCS-induced liver fibrosis.

Sources:

• Liu et al. (2026)
• Peng et al. (2024)
• Seki et al. (2007)