Environmental perfluoroalkyl acid exposures are associated with liver disease characterized by apoptosis and altered serum adipocytokines

Environ Pollut. 2019 Apr;247:1055-1063. doi: 10.1016/j.envpol.2019.01.064. Epub 2019 Jan 18.

Abstract

Exposures to perfluoroalkyl substances (PFAS) including perfluoroalkyl acids (PFAAs) are associated with increased liver enzymes in cohort studies including the C8 Health Study. In animal models, PFAAs disrupt hepatic lipid metabolism and induce apoptosis to cause nonalcoholic fatty liver disease (NAFLD). PFAAs are immunotoxic and inhibit pro-inflammatory cytokine release from stimulated leukocytes in vitro. This cross-sectional study tests the hypothesis that environmental PFAAs are associated with increased hepatocyte apoptosis and decreased pro-inflammatory cytokines in serum. Biomarkers previously associated with PFAS exposures and/or NAFLD were evaluated as secondary endpoints. Two hundred adult C8 Health Study participants were included. Measured serum biomarkers included: perfluorohexane sulfonate (PFHxS); perfluorooctanoic acid (PFOA); perfluorooctane sulfonate (PFOS); perfluorononanoic acid (PFNA); cytokeratin 18 M30 (CK18 M30, hepatocyte apoptosis); adipocytokines; insulin; and cleaved complement 3 (C3a). Confounder-adjusted linear regression models determined associations between PFAS and disease biomarkers with cut-offs determined by classification and regression tree analysis. CK18 M30 was positively associated with PFHxS (β = 0.889, p = 0.042); PFOA (β = 2.1, p = 0.005); and PFNA (β = 0.567, p = 0.03). Tumor necrosis factor α (TNFα) was inversely associated with PFHxS (β = -0.799, p = 0.001); PFOA (β = - 1.242, p = 0.001); and PFOS (β = -0.704, p < 0.001). Interleukin 8 was inversely associated with PFOS and PFNA. PFAAs were also associated with sexually dimorphic adipocytokine and C3a responses. Overall, PFAA exposures were associated with the novel combination of increased biomarkers of hepatocyte apoptosis and decreased serum TNFα. These data support previous findings from cohorts and experimental systems that PFAAs may cause liver injury while downregulated some aspects of the immune response. Further studies of PFAAs in NAFLD are warranted and should evaluate sex differences.

Keywords: Cytokeratin 18; Non-alcoholic fatty liver disease (NAFLD); Perfluoroalkyl acids (PFAAs); Perfluorooctanoic acid (PFOA); Tumor necrosis factor alpha (TNFα).

MeSH terms

  • Adipokines / blood*
  • Adult
  • Aged
  • Animals
  • Apoptosis / drug effects*
  • Biomarkers / blood*
  • Chemical and Drug Induced Liver Injury / etiology*
  • Cross-Sectional Studies
  • Environmental Exposure / adverse effects*
  • Female
  • Fluorocarbons / adverse effects*
  • Humans
  • Lipid Metabolism / drug effects*
  • Male
  • Middle Aged

Substances

  • Adipokines
  • Biomarkers
  • Fluorocarbons