Steatohepatitis/Metabolic Liver Disease
Hedgehog pathway and pediatric nonalcoholic fatty liver disease†
Article first published online: 1 APR 2013
Copyright © 2013 American Association for the Study of Liver Diseases
Volume 57, Issue 5, pages 1814–1825, May 2013
How to Cite
Swiderska-Syn, M., Suzuki, A., Guy, C. D., Schwimmer, J. B., Abdelmalek, M. F., Lavine, J. E. and Diehl, A. M. (2013), Hedgehog pathway and pediatric nonalcoholic fatty liver disease. Hepatology, 57: 1814–1825. doi: 10.1002/hep.26230
Potential conflict of interest: Nothing to report.
- Issue published online: 22 APR 2013
- Article first published online: 1 APR 2013
- Accepted manuscript online: 8 JAN 2013 05:29PM EST
- Manuscript Accepted: 30 NOV 2012
- Manuscript Received: 21 SEP 2012
- NIH. Grant Numbers: UO1DK061713, R01-DK053792, R01-DK077794, U01DK061734, UO1DK061713, U01DK061734, UL1TR000040
It is unclear why the histology of pediatric and adult nonalcoholic fatty liver disease (NAFLD) sometimes differs. In adults, severity of portal inflammation and fibrosis correlate with Hedgehog pathway activity. Hedgehog (Hh) signaling regulates organogenesis, but is silent in adult livers until injury reinduces Hh ligand production. During adolescence, liver development is completed and children's livers normally lose cells that produce and/or respond to Hh ligands. We postulated that fatty liver injury interferes with this process by increasing Hh ligand production, and theorized that hepatic responses to Hh ligands might differ among children according to age, gender, and/or puberty status. Using unstained liver biopsy slides from 56 children with NAFLD, we performed immunohistochemistry to assess Hh pathway activation and correlated the results with clinical information obtained at biopsy. Fibrosis stage generally correlated with Hh pathway activity, as demonstrated by the numbers of Hh-ligand-producing cells (P < 0.0001) and Hh-responsive (glioma-associated oncogene 2-positive [Gli2]) cells (P = 0.0013). The numbers of Gli2(+) cells also correlated with portal inflammation grade (P = 0.0012). Two distinct zonal patterns of Hh-ligand production, portal/periportal versus lobular, were observed. Higher portal/periportal Hh-ligand production was associated with male gender. Male gender and prepuberty were also associated with ductular proliferation (P < 0.05), increased numbers of portal Gli2(+) cells (P < 0.017) and portal fibrosis.
The portal/periportal (progenitor) compartment of prepubescent male livers exhibits high Hh pathway activity. This may explain the unique histologic features of pediatric NAFLD because Hh signaling promotes the fibroductular response. (HEPATOLOGY 2013)