title: Longitudinal study of circulating miR-122 in a rat model of non-alcoholic fatty liver disease.
abstract: BACKGROUND
  Circulating microRNAs (miRs) may be promising biomarkers for several diseases. We previously found that miR-122 can function as a biomarker for non-alcoholic fatty liver disease (NAFLD). However, little is known regarding the time course of circulating miR-122 levels during the development of NAFLD. Here, we examined circulating miR-122 levels using a rat model of NAFLD.
  
  
  METHODS
  To clarify changes in serum levels of miR-122 during development of NAFLD, experimental rats were fed a high-fat diet (HFD) for 2-10 weeks, while control rats received standard chow. Serum and liver tissue was collected from all animals at 2, 6, and 10 weeks of feeding. Clinical laboratory parameters (cholesterol, TG, AST, ALT, NEFA) were determined by biochemistry analyzer. Hepatic lipid accumulation was estimated by Oil red O staining. Circulating miR-122 levels were then measured by real-time polymerase chain reaction.
  
  
  RESULTS
  Over the 10 weeks of feeding, body weight, total liver lipids, and liver and serum triacylglycerol were increased in the HFD group compared to the control group. However, no significant changes in serum alanine aminotransferase activity were observed, suggesting that NAFLD status was mild. In contrast, we observed drastic up-regulation of circulating miR-122 levels. Our findings suggest that serum miR-122 level is indeed useful for assessing early NAFLD and might be superior to clinical markers traditionally used to monitor hepatic disease.
authors.affiliation: Department of Hygiene, Fujita Health University School of Medicine, Toyoake, Japan. Electronic address: hyamada@fujita-hu.ac.jp.
authors.forename: Hiroya
authors.initials: H
authors.lastname: Yamada
authors.affiliation: Department of Clinical Biochemistry, Fujita Health University School of Health Sciences, Toyoake, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Ohashi
authors.affiliation: Department of Public Health, Fujita Health University School of Health Sciences, Toyoake, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Suzuki
authors.affiliation: Department of Biochemistry, Fujita Health University School of Medicine, Toyoake, Japan.
authors.forename: Eiji
authors.initials: E
authors.lastname: Munetsuna
authors.affiliation: Department of Joint Research Laboratory of Clinical Medicine, Fujita Health University School of Medicine, Toyoake, Japan.
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Ando
authors.affiliation: Department of Clinical Biochemistry, Fujita Health University School of Health Sciences, Toyoake, Japan.
authors.forename: Mirai
authors.initials: M
authors.lastname: Yamazaki
authors.affiliation: Department of Clinical Biochemistry, Fujita Health University School of Health Sciences, Toyoake, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Ishikawa
authors.affiliation: Department of Clinical Physiology, Fujita Health University School of Health Sciences, Toyoake, Japan.
authors.forename: Naohiro
authors.initials: N
authors.lastname: Ichino
authors.affiliation: Department of Clinical Biochemistry, Fujita Health University School of Health Sciences, Toyoake, Japan.
authors.forename: Ryouji
authors.initials: R
authors.lastname: Teradaira
authors.affiliation: Department of Hygiene, Fujita Health University School of Medicine, Toyoake, Japan.
authors.forename: Shuji
authors.initials: S
authors.lastname: Hashimoto
mesh_terms: D000410:Alanine Transaminase / Q000097:blood; D000818:Animals; D001219:Aspartate Aminotransferases / Q000097:blood; D001391:Azo Compounds; D015415:Biomarkers / Q000097:blood; D002784:Cholesterol / Q000097:blood; D059305:Diet, High-Fat; D004195:Disease Models, Animal; D042241:Early Diagnosis; D005230:Fatty Acids, Nonesterified / Q000097:blood; D006651:Histocytochemistry; D006801:Humans; D008099:Liver / Q000378:metabolism* / Q000473:pathology; D008137:Longitudinal Studies; D008297:Male; D035683:MicroRNAs / Q000097:blood*; D065626:Non-alcoholic Fatty Liver Disease / Q000097:blood* / Q000175:diagnosis* / Q000209:etiology / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D014280:Triglycerides / Q000097:blood
chemical_list: D001391:Azo Compounds; D015415:Biomarkers; D005230:Fatty Acids, Nonesterified; C580643:MIRN122 microRNA, rat; D035683:MicroRNAs; D014280:Triglycerides; D002784:Cholesterol; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase; C011049:oil red O
keywords: Circulating miRNA; Non-alcoholic fatty liver disease; Serum miRNA; miR-122