Lipidomic Determination of Serum Lipids by Ultra-High Performance Liquid Chromatography - Mass Spectrometry (UPLC-MS) for the Characterization of Nonalcoholic Fatty Liver Disease (NAFLD)

Nonalcoholic fatty liver disease (NAFLD) is highly prevalent with identifiable risk factors including obesity, hyperlipidemia and diabetes. A lipidomic approach was taken to quantify the major lipid classes in human serum. Comprehensive characterization of serum lipids determined by ultraperformance liquid chromatography (UPLC)-mass spectrometry (MS) was performed in NAFLD patients and healthy controls. Nine lipid subgroups including lysophosphatidylcholine (LPC), lysophosphatidylethanolamine (LPE), phosphatidylcholine (PC), phosphatidylethanolamine (PE), cholesterol ester (ChE), diacylglyceride (DG), triglyceride (TG), sphingomyelin (SM), and ceramide (Cer) were determined in the positive ionization mode. The current study further corroborates existing evidence that increased TG and DG accumulation is the hallmark. The results showed that compared with healthy controls, the abundance of PC in the sera of NAFLD patients decreased, and the phosphatidylethanolamine (PE) level increased, resulting in a reduced PC/PE ratio in NAFLD patients. In NAFLD samples, Cer(18:0/16:0), Cer(18:1/24:0), and Cer(18:1/24:1) were present at significantly higher levels than in controls, while the Cer(18:0/14:0) and Cer(18:0/20:0) levels were lower. In addition, the determination of sphingolipids showed that the abundances of long-chain ceramides were significantly increased in NAFLD patients. These results demonstrate the identification of NAFLD using UPLC-MS lipidomics and provide insights into changes in lipids associated with this disease.