title: Circulating extracellular vesicles with specific proteome and liver microRNAs are potential biomarkers for liver injury in experimental fatty liver disease.
abstract: OBJECTIVE
  Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in both adult and children. Currently there are no reliable methods to determine disease severity, monitor disease progression, or efficacy of therapy, other than an invasive liver biopsy.
  
  
  METHODS
  Choline Deficient L-Amino Acid (CDAA) and high fat diets were used as physiologically relevant mouse models of NAFLD. Circulating extracellular vesicles were isolated, fully characterized by proteomics and molecular analyses and compared to control groups. Liver-related microRNAs were isolated from purified extracellular vesicles and liver specimens.
  
  
  RESULTS
  We observed statistically significant differences in the level of extracellular vesicles (EVs) in liver and blood between two control groups and NAFLD animals. Time-course studies showed that EV levels increase early during disease development and reflect changes in liver histolopathology. EV levels correlated with hepatocyte cell death (r2 = 0.64, p<0.05), fibrosis (r2 = 0.66, p<0.05) and pathological angiogenesis (r2 = 0.71, p<0.05). Extensive characterization of blood EVs identified both microparticles (MPs) and exosomes (EXO) present in blood of NAFLD animals. Proteomic analysis of blood EVs detected various differentially expressed proteins in NAFLD versus control animals. Moreover, unsupervised hierarchical clustering identified a signature that allowed for discrimination between NAFLD and controls. Finally, the liver appears to be an important source of circulating EVs in NAFLD animals as evidenced by the enrichment in blood with miR-122 and 192--two microRNAs previously described in chronic liver diseases, coupled with a corresponding decrease in expression of these microRNAs in the liver.
  
  
  CONCLUSIONS
  These findings suggest a potential for using specific circulating EVs as sensitive and specific biomarkers for the noninvasive diagnosis and monitoring of NAFLD.
authors.affiliation: Department of Pediatrics, University of California San Diego, La Jolla, California, United States of America.
authors.forename: Davide
authors.initials: D
authors.lastname: Povero
authors.affiliation: Department of Pediatrics, University of California San Diego, La Jolla, California, United States of America.
authors.forename: Akiko
authors.initials: A
authors.lastname: Eguchi
authors.affiliation: Department of Biostatistics/Bioinformatics - Moores Cancer Center, University of California San Diego, La Jolla, California, United States of America.
authors.forename: Hongying
authors.initials: H
authors.lastname: Li
authors.affiliation: Department of Pediatrics, University of California San Diego, La Jolla, California, United States of America.
authors.forename: Casey D
authors.initials: CD
authors.lastname: Johnson
authors.affiliation: Department of Pathology, VA San Diego Healthcare System, San Diego, California, United States of America.
authors.forename: Bettina G
authors.initials: BG
authors.lastname: Papouchado
authors.affiliation: Department of Pediatrics, University of California San Diego, La Jolla, California, United States of America.
authors.forename: Alexander
authors.initials: A
authors.lastname: Wree
authors.affiliation: Department of Biostatistics/Bioinformatics - Moores Cancer Center, University of California San Diego, La Jolla, California, United States of America.
authors.forename: Karen
authors.initials: K
authors.lastname: Messer
authors.affiliation: Department of Pediatrics, University of California San Diego, La Jolla, California, United States of America.
authors.forename: Ariel E
authors.initials: AE
authors.lastname: Feldstein
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000097:blood; D055252:Cell-Derived Microparticles / Q000235:genetics / Q000378:metabolism*; D002796:Choline Deficiency / Q000150:complications; D059305:Diet, High-Fat / Q000009:adverse effects; D004195:Disease Models, Animal; D055354:Exosomes / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008099:Liver / Q000378:metabolism* / Q000473:pathology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D035683:MicroRNAs / Q000097:blood*; D065626:Non-alcoholic Fatty Liver Disease / Q000209:etiology / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D020543:Proteome / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D035683:MicroRNAs; D020543:Proteome