Background & Aims
Activation of hepatic stellate cells (HSC) and transdifferentiation to myofibroblasts
following liver injury is the main culprit for hepatic fibrosis. Myofibroblasts show
increased proliferation, migration, contraction, and production of extracellular matrix
(ECM). In vitro, HMG-CoA reductase inhibitors (statins) inhibit proliferation and induce apoptosis
of myofibroblastic HSC. To investigate the antifibrotic effects of atorvastatin in vivo we used bile duct ligated rats (BDL).
Methods
BDL rats were treated with atorvastatin (15 mg/kg/d) immediately after ligation (prophylactically) or in on-going fibrosis (therapeutically).
Fibrosis was assessed by hydroxyproline content and Sirius-red staining. The activation
of HSC was investigated by analysis of αSMA expression. mRNA levels of cytokines and
procollagen were analyzed by RT-PCR, and MMP-2 activity by zymography. Proliferation
was assessed by expression of cathepsins (B and D), proliferating cell nuclear antigen
(PCNA), and Ki67-staining. Apoptosis was characterized by caspase-3 activity, cleavage
of PARP-1, and TUNEL assay. Hepatic inflammation was investigated by serum parameters
and liver histology.
Results
Prophylactic and early therapy with atorvastatin significantly attenuated fibrosis
and HSC activation. Later therapy lacked significant effects on fibrosis but reduced
profibrotic cytokine expression and led to a more quiescent state of HSC with less
proliferation and apoptosis, while hepatic inflammation did not change.
Conclusions
This study shows that very early atorvastatin treatment inhibits HSC activation and
fibrosis in the BDL model in vivo, while late treatment reduces HSC turnover and activity. Our findings underline that
long-term studies in humans are warranted.
Abbreviations:
HSC (hepatic stellate cells), ECM (extracellular matrix), TGFβ (transforming growth factor-β), CTGF (connective tissue growth factor), PDGFβ-R (platelet-derived growth factor-β receptor), HMG-CoA-R (3-hydroxy-3-methylglutaryl-coenzyme-A-reductase), BDL (bile duct ligation), PCNA (proliferating cell nuclear antigen), PARP-1 (poly (ADP ribose) polymerase), ELISA (enzyme-linked immunosorbent assay), AST (aspartate aminotransferase), ALT (alanine aminotransferase), HCl (hydrogen chloride), αSMA (α-smooth muscle actin), SDS–PAGE (sodium dodecyl sulfate–polyacrylamide gel electrophoresis), RT-PCR (real-time polymerase chain reaction), CT-value (number of cycles), SEM (standard error of the mean), MMP-2 (matrix metalloproteinase-2), GAPDH (glyceraldehydes-3-P dehydrogenase)Keywords
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Article info
Publication history
Published online: July 01, 2010
Accepted:
April 15,
2010
Received in revised form:
March 23,
2010
Received:
November 6,
2009
Identification
Copyright
© 2010 European Association for the Study of the Liver. Published by Elsevier Inc. All rights reserved.
