title: Rapid chromatographic method to decipher distinct alterations in lipid classes in NAFLD/NASH.
abstract: OBJECTIVE
  To establish a simple method to quantify lipid classes in liver diseases and to decipher the lipid profile in p62/IMP2-2/IGF2BP2-2 transgenic mice.
  
  
  METHODS
  Liver-specific overexpression of the insulin-like growth factor 2 mRNA binding protein p62/IMP2-2/IGF2BP2-2 was used as a model for steatosis. Steatohepatitis was induced by feeding a methionine-choline deficient diet. Steatosis was assessed histologically. For thin layer chromatographic analysis, lipids were extracted from freeze-dried tissues by hexane/2-propanol, dried, redissolved, and chromatographically separated by a two-solvent system. Dilution series of lipid standards were chromatographed, detected, and quantified. The detection was performed by either 2',7'-dichlorofluoresceine or a sulfuric acid/ethanol mixture.
  
  
  RESULTS
  Histological analyses confirmed steatosis and steatohepatitis development. The extraction, chromatographic, and detection method showed high inter-assay reproducibility and allowed quantification of the different lipid classes. The analyses confirmed an increase of triglycerides and phosphatidylethanolamine and a decrease in phosphatidylcholine in the methionine-choline deficient diet. The method was used for the first time to asses the lipid classes induced in the p62-overexpressing mouse model and showed a significant increase in all detected lipid species with a prominent increase of triglycerides by 2-fold. Interestingly, the ratio of phosphatidylcholine to phosphatidylethanolamine was decreased, as previously suggested as a marker in the progression from steatosis to steatohepatitis.
  
  
  CONCLUSIONS
  The thin layer chromatography analysis allows a reliable quantification of lipid classes and provides detailed insight into the lipogenic effect of p62.
authors.affiliation: Stephan Laggai, Yvette Simon, Theo Ranssweiler, Alexandra K Kiemer, Sonja M Kessler, Department of Pharmacy, Pharmaceutical Biology, Saarland University, Saarbruecken 66123, Germany.
authors.forename: Stephan
authors.initials: S
authors.lastname: Laggai
authors.forename: Yvette
authors.initials: Y
authors.lastname: Simon
authors.forename: Theo
authors.initials: T
authors.lastname: Ranssweiler
authors.forename: Alexandra K
authors.initials: AK
authors.lastname: Kiemer
authors.forename: Sonja M
authors.initials: SM
authors.lastname: Kessler
keywords: IMP2/IGF2BP2; Methionine choline deficient diet; Non alcoholic fatty liver disease; Non alcoholic steatohepatitis; Phosphatidylcholine/phosphatidylethanolamine ratio; Polar lipids; Thin layer chromatography; Triglycerides; neutral lipids; p62