title: Chymase inhibitor prevents the nonalcoholic steatohepatitis in hamsters fed a methionine- and choline-deficient diet.
abstract: OBJECTIVE
  Mast cells may be involved in the pathogenesis of nonalcoholic steatohepatitis (NASH). The mast cell protease chymase contributes to the formation of angiotensin II and matrix metalloproteinase (MMP)-9, both of which are intimately involved in liver fibrosis. Therefore, we hypothesized that chymase plays an important role in the development of NASH.
  
  
  METHODS
  Hamsters were fed a methionine- and choline-deficient (MCD) diet for 8 weeks. These animals were divided into two groups and received either TY-51469 (1 mg/kg per day) or placebo. A third group was fed a normal diet as a control.
  
  
  RESULTS
  Total plasma bilirubin, triglycerides, and hyaluronic acid levels were significantly higher in the MCD diet-fed hamsters than in the normal diet-fed hamsters, but the levels were significantly lower in chymase inhibitor-treated MCD diet-fed hamsters than in placebo-treated MCD diet-fed hamsters. Using histological analysis, marked steatosis and fibrosis were observed in MCD diet-fed hamsters, but these changes were significantly attenuated by treatment with the chymase inhibitor. Increases in mast cells and chymase-positive cells were observed in the liver after the MCD diet, but the increases disappeared in the chymase inhibitor-treated group. The significant increase observed in chymase activity in liver tissue extract from the MCD diet-fed group was also reduced by treatment with the chymase inhibitor. Chymase inhibition significantly reduced not only angiotensin II expression but also matrix metallopeptidase 9 activity in MCD diet-fed hamsters.
  
  
  CONCLUSIONS
  These findings demonstrate that the mast cell protease chymase may play a crucial role in the development of NASH in hamsters.
authors.affiliation: Department of Pharmacology, Osaka Medical College, Daigaku-machi, Takatsuki, Japan.
authors.forename: Keitaro
authors.initials: K
authors.lastname: Tashiro
authors.forename: Shinji
authors.initials: S
authors.lastname: Takai
authors.forename: Denan
authors.initials: D
authors.lastname: Jin
authors.forename: Hiromi
authors.initials: H
authors.lastname: Yamamoto
authors.forename: Koji
authors.initials: K
authors.lastname: Komeda
authors.forename: Michihiro
authors.initials: M
authors.lastname: Hayashi
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Tanaka
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Tanigawa
authors.forename: Mizuo
authors.initials: M
authors.lastname: Miyazaki