Studies on the regulation of lipid metabolism and the mechanism of the aqueous and ethanol extracts of Usnea
BIOMEDICINE & PHARMACOTHERAPY
Authors: Zhu, Jiali; Zhang, Xuemei; Chen, Xiu; Sun, Yong; Dai, Yaolan; Chen, Chang; Zhang, Tiane; Yan, Zhiyong
Abstract
Objectives: Usnea is a lichen of Usnea diffracta Vain and Usnea longissima Ach, which belongs to the genus Usnea Adans of Usneaceae. Usnea exerts numerous pharmacological activities, while its lipid regulatory activities remain unreported. This study aims to evaluate the effects of aqueous and ethanol extracts of Usnea on the regulation of lipid metabolism and to explore the possible mechanism. Methods: Hyperlipidemia rat model was established by feeding with high-fat diet for 45 days. Therapy rats were intragastrically administered with simvastatin (0.004 g/kg/d), Usnea aqueous extract (2.766 g/kg/d), or Usnea ethanol extract (2.766 g/kg/d) for 20 days. Pharmacodynamic effects, including body weight, serum and liver lipid levels, total bile acid (TBA), aspartate aminotransferase (AST), alanine aminotransferase (ALT), liver index, and hepatic morphological changes were evaluated. To explore the mechanisms, the lipase activities and protein expressions related to lipid metabolism were detected. Results: Compared with the model group, aqueous and ethanol extracts of Usnea can slow down the weight gain of rats, significantly reduce the serum levels of total cholesterol, triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), and the liver contents of TG, LDL-C, as well as significantly increase the contents of high-density lipoprotein cholesterol in serum. In addition, aqueous and ethanol extracts of Usnea can significantly reduce the serum contents of AST and ALT. Furthermore, ethanol extract of Usnea can also significantly reduce the TBA content in serum and liver index. Liver tissue pathological observation showed that aqueous and ethanol extracts of Usnea can improve cell degeneration to a certain extent. Aqueous and ethanol extracts of Usnea can significantly reduce sterol regulatory element-binding proteins-1c, and liver X receptor alpha (LXR-alpha) protein expressions. Furthermore, aqueous extract of Usnea can significantly increase hepatic lipase activity and promote apoprotein A5 (ApoA5) protein expression. Conclusions: These findings strongly suggest that the aqueous and ethanol extracts of Usnea play significant roles in regulating lipid metabolism, and the ethanol extract exhibits higher activity than the aqueous extract. The mechanism of the regulation of lipid metabolism by Usnea aqueous extract may involve the increased ApoA5 protein expression via inhibition of the LXR-a signal pathway; however, the mechanism of the regulation of lipid metabolism by Usnea ethanol extract remains to be further studied. (C) 2017 Elsevier Masson SAS. All rights reserved.
A 3-SNP gene risk score and a metabolic risk score both predict hypertriglyceridemia and cardiovascular disease risk
JOURNAL OF CLINICAL LIPIDOLOGY
Authors: Verbeek, Rutger; Oldoni, Federico; Surendran, R. Preethi; Zwinderman, Ailko H.; Khaw, Kay T.; Stroes, Erik S. G.; Wareham, Nick J.; Boekholdt, S. Matthijs; Dallinga-Thie, Geesje M.
Abstract
BACKGROUND: Evidence on the causal link between plasma triglyceride (TG) levels and risk for cardiovascular disease (CVD) has recently emerged. Individuals with the metabolic syndrome have an increased risk for acquiring elevated TG levels later in life. Moreover, common DNA sequence variations in genes affecting TG levels identify individuals at risk for elevated plasma TG levels. OBJECTIVE: We evaluated whether a 3-single nucleotide polymorphism (SNP) TG gene risk score (GRS) and a metabolic risk score (MetRS) both improved CVD risk prediction. METHODS: A 3-SNP GRS and MetRS were generated in the EPIC-Norfolk cohort (n = 20,074) based on 3 SNPs in LPL and APOA5 or the number of Metabolic Syndrome criteria present (maximum 5), respectively. The associations between the 3-SNP GRS, MetRS, TG levels, and CVD risk were evaluated. RESULTS: The 3-SNP GRS and MetRS were both linearly associated with plasma TG levels, that is, +0.25 mmol/L [95% CI 0.22-0.27] per allele change (P <.001) and +0.72 mmol/L [95% CI 0.70-0.73] per increase of number of metabolic syndrome risk score points (P <.001), respectively. We observed a positive association between the 3-SNP GRS and the risk of CVD with an adjusted hazard ratio (HR) of 1.35 [95% CI 1.04-1.74] for the highest versus the lowest GRS, which was independent of the MetRS. For the MetRS, the adjusted HR was 2.03 [95% CI 1.73-2.40] for the highest versus the lowest MetRS. CONCLUSION: Both the 3-SNP GRS and the MetRS are associated with increased plasma TG levels and increased risk for CVD. 2019 National Lipid Association. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).