title: MCD diet-induced steatohepatitis is associated with alterations in asymmetric dimethylarginine (ADMA) and its transporters.
abstract: Using an experimental model of NASH induced by a methionine-choline-deficient (MCD) diet, we investigated whether changes occur in serum and tissue levels of asymmetric dimethylarginine (ADMA). Male Wistar rats underwent NASH induced by 8-week feeding with an MCD diet. Serum and hepatic biopsies at 2, 4 and 8 weeks were taken, and serum enzymes, ADMA and nitrate/nitrite (NOx), were evaluated. Hepatic biopsies were used for mRNA and protein expression analysis of dimethylarginine dimethylaminohydrolase-1 (DDAH-1) and protein methyltransferases (PRMT-1), enzymes involved in ADMA metabolism and synthesis, respectively, and ADMA transporters (CAT-1, CAT-2A and CAT-2B). Lipid peroxides (TBARS), glutathione, ATP/ADP and DDAH activity were quantified. An increase in serum AST and ALT was detected in MCD animals. A time-dependent decrease in serum and tissue ADMA and increase in mRNA expression of DDAH-1 and PRMT-1 as well as higher rates of mRNA expression of CAT-1 and lower rates of CAT-2A and CAT-2B were found after 8-week MCD diet. An increase in serum NOx and no changes in protein expression in DDAH-1 and CAT-1 and higher content in CAT-2 and PRMT-1 were found at 8 weeks. Hepatic DDAH activity decreased with a concomitant increase in oxidative stress, as demonstrated by high TBARS levels and low glutathione content. In conclusion, a decrease in serum and tissue ADMA levels in the MCD rats was found associated with a reduction in DDAH activity due to the marked oxidative stress observed. Changes in ADMA levels and its transporters are innovative factors in the onset and progression of hepatic alterations correlated with MCD diet-induced NASH.
authors.affiliation: Department of Internal Medicine and Therapeutics, University of Pavia, Via Ferrata 9A, 27100, Pavia, Italy.
authors.forename: Laura G
authors.initials: LG
authors.lastname: Di Pasqua
authors.affiliation: Department of Internal Medicine and Therapeutics, University of Pavia, Via Ferrata 9A, 27100, Pavia, Italy.
authors.forename: Clarissa
authors.initials: C
authors.lastname: Berardo
authors.affiliation: Department of Molecular Medicine, Fondazione IRCCS Policlinico S. Matteo and University of Pavia, Pavia, Italy.
authors.forename: Vittoria
authors.initials: V
authors.lastname: Rizzo
authors.affiliation: Department of Internal Medicine and Therapeutics, University of Pavia, Via Ferrata 9A, 27100, Pavia, Italy.
authors.forename: Plinio
authors.initials: P
authors.lastname: Richelmi
authors.affiliation: Histochemistry and Cytometry Unit, IGM-CNR, c/o Biotechnology and Biology Department, University of Pavia, Pavia, Italy.
authors.forename: Anna Cleta
authors.initials: AC
authors.lastname: Croce
authors.affiliation: Department of Internal Medicine and Therapeutics, University of Pavia, Via Ferrata 9A, 27100, Pavia, Italy. mariapia.vairetti@unipv.it.
authors.forename: Mariapia
authors.initials: M
authors.lastname: Vairetti
authors.affiliation: Department of Internal Medicine and Therapeutics, University of Pavia, Via Ferrata 9A, 27100, Pavia, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Ferrigno
mesh_terms: D026923:Amino Acid Transport Systems, Basic / Q000096:biosynthesis*; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives* / Q000097:blood; D002794:Choline; D004195:Disease Models, Animal; D005234:Fatty Liver / Q000097:blood*; D005786:Gene Expression Regulation; D008297:Male; D008715:Methionine / Q000172:deficiency*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D026923:Amino Acid Transport Systems, Basic; C018524:N,N-dimethylarginine; D001120:Arginine; D008715:Methionine; D002794:Choline
keywords: ADMA; Cationic transporters; DDAH; Liver