FIGURE 4.

Liver mRNA expression and protein content and relationships to liver-TAG DNL and VLDL-TAG DNL. Data are reported as median with confidence interval, with sample sizes below. Kruskal–Wallis ANOVA was performed between the groups, and the P value is presented above each bar graph. If significant, Dunn’s multiple comparisons test was performed to test the significance of each group. (A) Liver mRNA expression of key enzymes involved in the DNL and TAG synthesis pathways (n = 32–44 per gene). In the NAFL, Borderline NASH, and NASH groups, the data suggested that excess liver-CE (Figure 2) was due to decreased hydrolase activity, whereas in the NASH group, the data suggest an additional effect of increased esterification by SOAT2 and decreased nCEH activity. (B) Liver protein contents of enzymes for TAG and fatty acid synthesis and fatty acid transport (n = 37–40 per protein).

Pearson correlation analysis was performed, and a significant relation was observed between (C) liver FASN protein level and fractional DNL in liver-TAG (total n = 37, No-NAFLD n = 7, NAFL n = 5, Borderline NASH n = 12, NASH n = 12, R = 0.470, P = 0.003), and (D) fractional DNL in VLDL-TAG and fractional DNL in liver-TAG (total n = 49, No-NAFLD n = 8, NAFL n = 11, Borderline NASH n = 14, NASH n = 16; R = 0.747, P < 0.001). Abbreviations: ANOVA, analysis of variance; AU, arbitrary unit; CE, cholesterol ester; DNL, de novo lipogenesis; Fxn, fractional; NAFL, noalcoholic fatty liver; NAFLD, nonalcholic fatty liver disease; NASH, nonalcoholic steatohepatitis; RQ, fold change relative to GAPDH; TAG, triacylglycerol; VLDL, very low-density lipoprotein.