Hedgehog pathway activation parallels histologic severity of injury and fibrosis in human nonalcoholic fatty liver disease

Cynthia D Guy, Ayako Suzuki, Marzena Zdanowicz, Manal F Abdelmalek, James Burchette, Aynur Unalp, Anna Mae Diehl, Bradley Aouizerat, NASH CRN

Research output: Contribution to journalArticlepeer-review

Abstract

UNLABELLED: The Hedgehog (HH)-signaling pathway mediates several processes that are deregulated in patients with metabolic syndrome (e.g., fat mass regulation, vascular/endothelial remodeling, liver injury and repair, and carcinogenesis). The severity of nonalcoholic fatty liver disease (NAFLD) and metabolic syndrome generally correlate. Therefore, we hypothesized that the level of HH-pathway activation would increase in parallel with the severity of liver damage in NAFLD. To assess potential correlations between known histologic and clinical predictors of advanced liver disease and HH-pathway activation, immunohistochemistry was performed on liver biopsies from a large, well-characterized cohort of NAFLD patients (n = 90) enrolled in the Nonalcoholic Steatohepatitis Clinical Research Network (NASH CRN) Database 1 study. Increased HH activity (evidenced by accumulation of HH-ligand-producing cells and HH-responsive target cells) strongly correlated with portal inflammation, ballooning, and fibrosis stage (each P < 0.0001), supporting a relationship between HH-pathway activation and liver damage. Pathway activity also correlated significantly with markers of liver repair, including numbers of hepatic progenitors and myofibroblastic cells (both P < 0.03). In addition, various clinical parameters that have been linked to histologically advanced NAFLD, including increased patient age (P < 0.005), body mass index (P < 0.002), waist circumference (P < 0.0007), homeostatic model assessment of insulin resistance (P < 0.0001), and hypertension (P < 0.02), correlated with hepatic HH activity.

CONCLUSION: In NAFLD patients, the level of hepatic HH-pathway activity is highly correlated with the severity of liver damage and with metabolic syndrome parameters that are known to be predictive of advanced liver disease. Hence, deregulation of the HH-signaling network may contribute to the pathogenesis and sequelae of liver damage that develops with metabolic syndrome.

Original languageEnglish (US)
Pages (from-to)1711-21
Number of pages11
JournalHepatology
Volume55
Issue number6
DOIs
StatePublished - Jun 2012

Keywords

  • Adult
  • Aged
  • Cross-Sectional Studies
  • Fatty Liver
  • Female
  • Hedgehog Proteins
  • Humans
  • Kruppel-Like Transcription Factors
  • Liver
  • Liver Cirrhosis
  • Male
  • Middle Aged
  • Myofibroblasts
  • Non-alcoholic Fatty Liver Disease
  • Nuclear Proteins
  • Severity of Illness Index
  • Signal Transduction
  • Stem Cells

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