Holding the line on hepatic fat

Beneficial effects by intake of Euphausiacea pacifica on high-fat diet-induced obesity

Obesity is a major health problem showing increased incidence in developed and developing countries. We examined the effect of Euphausia pacifica (E. pacifica) (Pacific Krill) on high-fat diet (HFD)-induced obesity in C57BL/6 mice. No significant differences were observed in average food intake between the HFD and HFD with E. pacifica group, or the low-fat diet (LFD) and LFD with E. pacifica group for 18 weeks. The increased ratio of body weight in the HFD containing E. pacifica group was significantly reduced, being 10% lower than that with HFD group in the 18th week (HFD, 298.6±18.8% vs. HFD with E. pacifica, 267.8±16.2%; p<0.05), while the ratio for the LFD containing E. pacifica group was reduced by 4% compared with LFD group (LFD, 244.2±11.6% vs. LFD with E. pacifica, 234.1±18.0%). There were no effects of E. pacifica on total cholesterol levels in serum and liver, whereas the supplement of E. pacifica tended to decrease triglyceride levels in the HFD groups. The leptin level in serum was significantly decreased in the HFD group (p<0.01) by E. pacifica. The adipocyte area (1926±1275 μm(2)) in the HFD containing E. pacifica group was significantly reduced by 20% (p<0.001) compared with the HFD group. These results suggested that E. pacifica supplementation in the diet is beneficial for the prevention of HFD-induced obesity.

Effects of nuclear receptor FXR on the regulation of liver lipid metabolism in patients with non-alcoholic fatty liver disease

OBJECTIVE

The aim of this study was to explore the role of farnesoid X receptor (FXR) in liver lipid metabolism of non-alcoholic fatty liver disease (NAFLD) patients.

METHODS

In this study, pathology and clinical criteria confirmed NAFLD in patients. Fatty acid synthetase (FAS)-positive liver cells were visualized by laser scanning confocal microscopy. Levels of FXR, liver X receptor (LXR), sterol regulatory element binding protein 1C (SREBP-1C), and small heterodimer partner (SHP) proteins were detected by Western blot. FXR, LXR, and SHP mRNA levels were measured by real-time PCR.

RESULTS

In patients with NAFLD, a significant positive relationship between the degree of hepatic steatosis and serum triglycerides and cholesterol (correlation coefficient > 0.5, P < 0.05) was seen. The NAFLD patients had more FAS protein in liver, which suggests that there could have been more of fatty acid synthesis in hepatic cells (P < 0.05). The levels of FXR protein and mRNA were decreased in patients with NAFLD (P < 0.05), while those of LXR and SREBP-1C were increased (P < 0.05). The levels of SREBP-1C positively correlated with the degree of hepatic steatosis. There were no differences between the levels of SHP protein and mRNA both in NAFLD patients and normal controls (P > 0.05).

CONCLUSION

Our data showed that the decreased expression of hepatic FXR is associated with an increased expression of LXR, SREBP-1C, and hepatic triglyceride synthesis; furthermore, increased SREBP-1C is associated with the degree of hepatic steatosis in the NAFLD patients.