A compromised liver alters polychlorinated biphenyl-mediated toxicity

Area of Science:

• Environmental Health
• Toxicology
• Hepatology

Background:

• Polychlorinated biphenyls (PCBs) are environmental toxicants linked to liver and cardiovascular diseases.
• The liver's role in metabolism and response to injury is critical for homeostasis.
• Limited understanding exists on how a compromised liver responds to subsequent environmental insults.

Purpose of the Study:

• To investigate the role of a compromised liver in polychlorinated biphenyl (PCB)-induced toxicity.
• To define the implications of combined liver injury and PCB exposure on overall body homeostasis.
• To evaluate the impact of diet-induced liver injury on susceptibility to environmental toxicants.

Main Methods:

• Male C57Bl/6 mice were fed control (CD) or methionine-choline deficient (MCD) diets for 12 weeks.
• Mice were subsequently exposed to PCB126 or Aroclor1260, with analysis of inflammatory, calorimetry, and metabolic parameters.
• Hepatic gene expression and circulating inflammatory biomarkers were assessed.

Main Results:

• MCD diet induced liver steatosis; subsequent PCB126 exposure led to wasting syndrome and mortality.
• PCB exposure exacerbated hepatic fibrosis in MCD-fed mice.
• PCB126 induced steatosis and inflammation in control mice; both PCBs caused metabolic disturbances and extra-hepatic toxicity in MCD-fed mice.

Conclusions:

• Diet-induced liver injury significantly exacerbates PCB toxicity, leading to severe health outcomes.
• Environmental pollution can worsen existing liver conditions, impacting energy homeostasis and causing systemic effects.
• Findings are relevant to human populations with co-existing fatty liver disease and PCB exposure.