Dynamic lipid profile of hyperlipidemia mice

The Application of Metabolomics in Hyperlipidemia: Insights into Biomarker Discovery and Treatment Efficacy Assessment

Hyperlipidemia is a lipid metabolism disorder that refers to increased levels of total triglycerides (TGs), cholesterol (TC), and low-density lipoprotein-cholesterol (LDL-C) and decreased levels of high-density lipoprotein-cholesterol (HDL-C). It is a major public health issue with increased prevalence and incidence worldwide. The ability to identify individuals at risk of this disorder before symptoms manifest will facilitate timely intervention and management to avert potential complications. This can be achieved by employing metabolomics as an early detection method for the diagnostic biomarkers of hyperlipidemia. Metabolomics is an analytical approach used to detect and quantify metabolites. This provides the ability to explain the metabolic processes involved in the development and progression of certain diseases. In recent years, interest in the use of metabolomics to identify disease biomarkers has increased, and several biomarkers have been discovered, such as docosahexaenoic acid, glycocholic acid, citric acid, betaine, and carnitine. This review discusses the primary metabolic alterations in the context of hyperlipidemia. Furthermore, we provide an overview of recent studies on the application of metabolomics to the assessment of the efficacy of traditional herbal products and common lipid-lowering medications.

Protective role of thymoquinone in hyperlipidemia-induced liver injury in LDL-R-/-mice

BACKGROUND

Hyperlipidemia, a heterogeneous group of disorders characterized by elevated plasma lipids in the blood, causes severe health problems, leading to fatty liver disease and nonalcoholic fatty liver disease. Thymoquinone, the major active chemical component of Nigella sativa, reportedly exerts a vast array of biological effects. Various studies have reported that Thymoquinone protects against liver injury.

AIMS

The aim of this study was to investigate the possible protective effects of Thymoquinone against liver injury in hyperlipidemia-induced LDL-R-/- mice.

METHODS

Eight-week-old male LDL-R-/- mice were randomly divided into three groups: a control group fed a normal diet and two groups fed a high-cholesterol diet or high-cholesterol diet mixed with Thymoquinone. All groups were fed different diets for 8 weeks. Blood samples were obtained from the inferior vena cava and collected in serum tubes. The samples were then stored at - 80 °C until used. Longitudinal sections of liver tissues were fixed in 10% formalin and then embedded in paraffin for histological evaluation. The remainder of the liver tissues were snap-frozen in liquid nitrogen for reverse transcription-polymerase chain reaction or western blotting.

RESULTS

Our results demonstrated that Thymoquinone administration significantly reduced liver histological alterations by hyperlipidemia. Thymoquinone mitigated hyperlipidemia-induced liver injury as indicated by the suppression of metabolic characteristics, liver biochemical parameters, pyroptosis indicators, a macrophage marker, and the phosphatidylinositide 3-kinase signaling pathway.

CONCLUSIONS

Thymoquinone is a potential therapeutic agent for hyperlipidemia-induced liver injury.

Hypolipidemic Activity and Mechanism of Action of Sargassum fusiforme Polysaccharides

Sargassum fusiforme polysaccharide (SFP) is a kind of biologically active macromolecule with biological functions. In this study, oxidative stress and high-fat HepG2 cell models were established to investigate its lipid-lowering activity and mechanism of action. It was found that SFP and its two isolated fractions had antioxidant effects on the cells. It was also found the polysaccharides decreased the content of total cholesterol and total triglyceride in the high-fat cells. RT-qPCR assays revealed that the three polysaccharides down-regulated the mRNA expression level of ACC, PPARγ, and SREBP-2. It could be concluded that the hypolipidemic effect of SFPs is achieved via multiple pathways, including the regulation on the expression level of lipid metabolism-related key enzymes and factors, and binding with bile acids. The hypolipidemic effect of SFPs could be partially due to their antioxidant activity. SFPs developed in the present work have potential as ingredients of functional foods with hypolipidemic effect.

Marein reduces lipid levels via modulating the PI3K/AKT/mTOR pathway to induce lipophagy

ETHNOPHARMACOLOGICAL RELEVANCE

The capitulum of Coreopsis tinctoria Nutt. (CT, Xue-Ju in Chinese) is a precious medicine in Xinjiang Uygur Autonomous region of China. The Coreopsis tinctoria Nutt. is used to prevent and treat dyslipidemia, coronary heart disease, etc. Recent studies have shown that its extract has a pharmacological effect on hyperlipidemia and hyperglycemia.

AIM OF THE STUDY

The study aimed to systematically evaluate the lipid-lowering activity of CT through a mice model of hyperlipidemia and a human hepatoma G2 (HepG2) cells model of lipid accumulation, and to investigate its main active components and mechanism.

MATERIALS AND METHODS

Biochemical analysis of blood/liver lipids and liver histopathology were used to evaluate the effect of the aqueous extract of Coreopsis tinctoria Nutt. (AECT) on hyperlipidemia mice. High-performance liquid chromatography (HPLC) analysis was used to identify the main components in the AECT. Oil red O staining, immunofluorescence, western blotting, and determination of the total cholesterol (TC), total triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) were used to further study the effect and potential mechanism of the AECT main components on sodium oleate-induced lipid accumulation in HepG2 cells.

RESULTS

We confirmed the lipid-lowering activity of the aqueous extract and further identified flavonoids as its main components. Among them, five Coreopsis tinctoria Nutt. flavonoids mixture (FM) significantly reduced lipid droplet area, lipid content, TC, TG, and LDL-C levels, and elevated HDL-C levels in HepG2 cells induced by sodium oleate. Furthermore, they increased lipophagy in HepG2 lipid-accumulating cells, while decreasing the ratio of p-PI3K/PI3K, p-AKT/AKT, and p-mTOR/mTOR. Most importantly, marein may be a key component.

CONCLUSIONS

Our study demonstrated that AECT, with flavonoids as the main component, can improve diet-induced hyperlipidemia in obese mice. Among the main five flavonoids, marein plays a key role in promoting lipophagy by regulating the PI3K/AKT/mTOR pathway, resulting in a lipid-lowering effect.

Hypolipidemic effects of macadamia oil are related to AMPK activation and oxidative stress relief: In vitro and in vivo studies

Macadamia oil is rich in monounsaturated fatty acids, especially a high level of palmitoleic acid, which may have beneficial health effects by lowering blood lipid levels. In our study, the hypolipidemic effects of macadamia oil and its potential mechanisms of action were investigated using a combination of in vitro and in vivo assays. The results showed that macadamia oil significantly reduced lipid accumulation, and improved triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) levels in oleic acid-induced high-fat HepG2 cells. The macadamia oil treatment also exhibited antioxidant effects, as seen by its ability to reduce reactive oxygen species and malondialdehyde (MDA) levels, and increase superoxide dismutase (SOD) activity. The effects of 1000 μg/mL of macadamia oil were comparable to that of 4.19 μg/mL simvastatin. The results of qRT-PCR and western blotting analyses indicated that macadamia oil effectively inhibited hyperlipidemia by reducing the expression levels of SREBP-1c, PPAR-γ, ACC and FAS and by enhancing the expression levels of HO-1, NRF2 and γ-GCS, via AMPK activation and oxidative stress relief, respectively. In addition, different doses of macadamia oil were found to significantly improve liver lipid accumulation, reduce serum and liver TC, TG, and LDL-C levels, increase HDL-C levels, increase antioxidant enzyme (SOD, GSH-Px, and T-AOC) activity, and decrease the MDA content of mice on a high-fat diet. These results indicated that macadamia oil had a hypolipidemic effect and provide insights that might facilitate the development of functional food and dietary supplements.

Dietary Interventions of Salmon and Silver Carp Phospholipids on Mice with Metabolic Syndrome Based on Lipidomics

The number of metabolic syndromes (MetS) is increasing, and a fish phospholipid diet can reduce the risk of MetS. In this study, the changes in lipid metabolism of colon contents were analyzed by extensive lipidomics in mice with metabolic syndrome by fish phospholipid diet, and mice were randomly divided into experimental groups with different diet types by establishing a MetS model. After 14 weeks, the mice were sacrificed and the serum and colon contents were collected. Ultra-high liquid phase tandem mass spectrometry was used for broadly targeted lipidomic analysis, and the qualitative and quantitative detection of lipid metabolism changes in the colonic contents of mice. Under the intervention of fish phospholipids, MetS mice were significantly inhibited, serum total cholesterol (TC) and triglycerides (TG) decreased, serum high-density lipoprotein (HDL-C) and low-density lipoprotein (LDL-C) levels were improved, fasting blood glucose and insulin levels decreased, and inflammatory factors decreased. Through screening, it was found that thirty-three lipid metabolites may be key metabolites and five have significantly changed metabolic pathways. Modularizing lipid metabolites, it is possible to understand the extent to which different types and concentrations of fish phospholipids affect metabolic syndrome. Therefore, our study may provide new therapeutic clues for improving MetS.

Isolation, structural characterization and bioactivities of polysaccharides from Laminaria japonica: A review

Laminaria japonica is a familiar marine plant and is often used as food due to its abundant carbohydrates, vitamins and minerals. As one of the main types of active substances in L. japonica, polysaccharides are widely used in the food and chemical industries and in medicine and healthcare due to their health benefits, such as immunoregulatory, antioxidant, and antidiabetic effects. However, there has been no systematic summary of the isolation, structural characterization and bioactivities of L. japonica polysaccharides (LJPs). Therefore, the present review includes a survey of extraction and purification methods for these bioactive molecules, along with a dissertation on the structural characterization of the carbohydrate components. Moreover, an overview of the most recent results related to LJP biological activities is provided. This review provides a useful reference for further research, production, and application of LJPs in functional foods and therapeutic agents.

Capsaicin Attenuates Oleic Acid-Induced Lipid Accumulation via the Regulation of Circadian Clock Genes in HepG2 Cells

As the major component in red chili peppers, capsaicin is useful in the prevention of lipid metabolism disorders. In this study, the attenuation effect of capsaicin on oleic acid (OA)-induced lipid accumulation in HepG2 cells was evaluated with respect to circadian clock gene expressions. Lipid profiles, including triacylglycerols, total cholesterols, high-density lipoproteins, low-density lipoproteins, and aspartate aminotransferase content, were measured using enzymatic assay kits. The mitochondrial membrane potential, cellular redox status, and lipid droplet morphology were also determined using different assay kits and staining methods. The mRNA and protein expressions of core circadian clock genes and major lipometabolism-related factors were assessed using RT-qPCR and western blotting. Results showed that 50 μM capsaicin alleviated the circadian desynchrony and inhibited OA-induced ROS overproduction (from 166.44 ± 12.63% to 119.90 ± 5.43%) and mitochondrial dysfunction (from 0.60 ± 0.08 to 0.83 ± 0.09, represented by the red/green fluorescence ratio) in HepG2 cells. The amelioration effect of capsaicin on OA-induced lipid accumulation was weakened after Bmal1-knockdown, demonstrating that the rhythmic expression of the circadian clock gene is involved in the regulation process of capsaicin in lipid metabolism.

GC-MS-Based Serum Metabolomic Investigations on the Ameliorative Effects of Polysaccharide from Turpiniae folium in Hyperlipidemia Rats

Hyperlipidemia, a typical metabolic disorder syndrome, can cause various cardiovascular diseases. The polysaccharides were found to have enormous potential in the therapy of hyperlipidemia. This study was aimed at evaluating the ameliorative effects of polysaccharide from Turpiniae folium (TFP) in rats with hyperlipidemia. A serum metabolomic method based on gas chromatography-mass spectrometry (GC-MS) was used to explore the detailed mechanism of TFP in rats with hyperlipidemia. The oxidative stress indicators, biochemical indexes, and inflammatory factors in serum and histopathological changes in the liver were also evaluated after 10-week oral administration of TFP in rats with high-fat diet-induced hyperlipidemia. TFP significantly relieved oxidative stress, inflammation, and liver histopathology and reduced blood lipid levels. Multivariate statistical approaches such as principal component analysis and orthogonal projection to latent structure square-discriminant analysis revealed clear separations of metabolic profiles among the control, HFD, and HFD+TFP groups, indicating a moderating effect of TFP on the metabolic disorders in rats with hyperlipidemia. Seven metabolites in serum, involved in glycine, serine, and threonine metabolism and aminoacyl-tRNA biosynthesis, were selected as potential biomarkers in rats with hyperlipidemia and regulated by TFP administration. It was concluded that TFP had remarkable potential for treating hyperlipidemia. These findings provided evidence for further understanding of the mechanism of action of TFP on hyperlipidemia.

Physicochemical and Biological Properties of Polysaccharides from Dictyophora indusiata Prepared by Different Extraction Techniques

In this study, different extraction techniques, including traditional hot water extraction (HWE), microwave-assisted extraction (MAE), pressurized assisted extraction (PAE), and ultrasonic-assisted extraction (UAE), were used to extract Dictyophora indusiata polysaccharides (DFPs), and their physicochemical and biological properties were compared. Results revealed that extraction yields of D. indusiata polysaccharides prepared by different extraction techniques ranged from 5.62% to 6.48%. D. indusiata polysaccharides prepared by different extraction techniques possessed similar chemical compositions and monosaccharide compositions, while exhibited different molecular weights (M_w), apparent viscosities, and molar ratios of constituent monosaccharides. In particularly, D. indusiata polysaccharides prepared by HWE (DFP-H) had the highest M_w and apparent viscosity among all DFPs, while D. indusiata polysaccharides extracted by UAE (DFP-U) possessed the lowest M_w and apparent viscosity. In addition, the in vitro antioxidant effects of D. indusiata polysaccharides prepared by PAE (DFP-P) and DFP-U were significantly higher than that of others. Indeed, both DFP-P and DFP-H exhibited much higher in vitro binding properties, including fat, cholesterol, and bile acid binding properties, and lipase inhibitory effects than that of D. indusiata polysaccharides prepared by MAE (DFP-M) and DFP-U. These findings suggest that the PAE technique has good potential for the preparation of D. indusiata polysaccharides with desirable bioactivities for the application in the functional food industry.

Matrix metalloproteinase activities and oxidative stress in newborn cardiac tissue of rabbit female fed high cholesterol-methionine diet

We study the effect of an enriched cholesterol-methionine diet administered to females on the cardiac tissue remodelling of the offspring during two successive pregnancies. Two groups are constituted, standard diet (SD) group fed a standard diet and CD group fed a combined diet (standard + cholesterol 1%-methionine 0.25%). The diet is administered during 80 days. The results show changes in serum and cardiac parameters of CD newborn, with the involvement of phospholipids (PLs) (phosphatidylethanolamine (PE) and phosphatidylcholine (PC), variations in malondialdehyde (MDA), conjugated diene (CD), and vitamin C [VIT-C] rates). Under the CD effect, serum matrix metalloproteinase (MMP)-2, pro-MMP-9, and MMP-9 activities change. As to cardiac MMP-2 activity, a rise is noticed in the second pregnancy. Histological analysis reveals constricted blood capillaries, collagen fibre deposits, and lipid accumulation in the CD newborn heart. Our study shows the amplified effect of the maternal cholesterol-methionine diet in the second pregnancy on newborn cardiac disorders (matrix remodelling, oxidative stress, and lipid accumulation).

Bifenthrin exerts proatherogenic effects via arterial accumulation of native and oxidized LDL in rats: the beneficial role of vitamin E and selenium

The purpose of this study was to investigate, for the first time, the effects of Bifenthrin (Bif) chronic exposure on plasmatic and aortic lipid parameters disturbance and their pro-atherogenic possibility in Wistar rats. The ameliorative role of vitamin E (Vit E) and selenium (Se) were also targeted. Thus, rats were treated by gastric gavage with combination of Vit E (100 mg/kg/bw) and Se (0.25 mg/kg/bw) in alone and co-treated groups for 90 days. Apart from control and Vit E-Se groups, all the groups were subjected to Bif (3 mg/kg, via gavage) toxicity. Results showed that Bif increased markedly plasmatic and aortic total cholesterol, LDL-cholesterol, native LDL-apoB-100, and oxidized-LDL, compared to the control. Moreover, Bif treatment significantly increased the plasmatic levels of the pro-inflammatory cytokines TNF-α, IL-2, and IL-6. In addition, the densitometric quantification of protein bands showed that the amount of hepatic native LDL-receptor protein decreased significantly in the intoxicated rats compared to the control group. The expression of arterial LDL receptors (LDLRs) and scavenger receptors (CD36) was amplified owing to Bif toxicity. This harmful effect was confirmed by histological study using Oil-Red-O staining. Owing to their antioxidant capacities, Vit E and Se have maintained all the changes in plasma and aorta lipids and prevented the pro-atherogenic effect observed in Bif-treated animals.

Metabolomics analysis of the therapeutic mechanism of Semen Descurainiae Oil on hyperlipidemia rats using 1 H-NMR and LC-MS

Semen descurainiae oil (SDO) is an important traditional Chinese medicine that was recently discovered to have the function of reducing blood lipids. Metabolomics analyses of plasma, liver and kidney in rats were performed using ¹ H-NMR and LC-MS to illuminate the lower blood lipid concentration effect of SDO, and niacin was considered as the active control. The measure of total cholesterol (TC) and low-density-lipoprotein cholesterol (LDL-C) in plasma showed that SDO treatment decreased significantly the content of TC and LDL-C. An orthogonal partial least squares-discriminant analysis approach was applied to identify the different metabolic profiles of plasma, liver and kidney in rats and to detect related potential biomarkers. The results suggested that the metabolic profiles of the control group and hyperlipidemia group showed significant difference and the SDO and niacin group had effective anti-hyperlipidemia function. The biomarkers primarily concern lipid metabolism, amino acid metabolism and glycometabolism, and the change in biomarkers indicated that hyperlipidemia could cause the unbalance of these metabolic pathways in vivo. SDO reduced blood lipids by repairing amino acid and lipid metabolism.

Anti-hyperlipidemic, antioxidant and organic protection effects of acidic-extractable polysaccharides from Dictyophora indusiata

In the present work, we investigated the anti-hyperlipidemic, antioxidant and organic protection effects of acidic-extractable Dictyophora indusiata polysaccharides (Ac-DPS) on hyperlipidemic mice induced by high-fat emulsion. The results demonstrated that Ac-DPS had impressive abilities to mitigate oxidative stress by increasing the activities of antioxidant enzyme and reducing the contents of lipid peroxide. Moreover, lipid levels in serum were returned to normal status. Besides, Ac-DPS exhibited potential hepatic and renal protection effects reflected by decreasing serum enzyme activities, lowering TBIL, UREA and CREA levels and increasing ALB content. At the same time, histopathological observations proved protective effects of Ac-DPS on organs. Subsequently, the physical properties of polysaccharide were also investigated by HPGPC and FT-IR. The above consequences confirmed the important role of Ac-DPS as a functional food and natural medicine in the fight against oxidative stress and the prevention of hyperlipidemia.

Anti-obesity and Hypolipidemic effects of garlic oil and onion oil in rats fed a high-fat diet

Background

Until now, little research concerning the lipid-lowering and anti-obesity functions of garlic oil and onion oil has been performed. The objective of this study was to explore the effects of garlic oil and onion oil on serum lipid levels in hyperlipidemia model rats, to provide a scientific basis for the prevention of hyperlipidemia through a dietary approach, and to explore the potential health benefits of garlic and onion.

Method

Ninety-six male Sprague-Dawley rats were randomly allocated into eight groups based on their body weight and serum levels of triglycerides (TG) and total cholesterol (TC). The rats received repeated oral administration of volatile oils extracted from garlic and onion for 60 days. Serum lipids and parameters of obesity were examined.

Results

The volatile oils suppressed the HFD-induced body weight gain and tended to decrease adipose tissue weight. The oils decreased the levels of TG, TC and LDL-C and increased the serum level of HDL-C compared with the rats in the hyperlipidemia model groups (P < 0.05). The oils were also effective at improving the lipid profile and alleviating hepatic steatosis.

Conclusion

Our results implied that garlic oil and onion oil have anti-obesity properties that can counteract the effects of an HFD on body weight, adipose tissue weight, and serum lipid profiles.

Electronic supplementary material

The online version of this article (10.1186/s12986-018-0275-x) contains supplementary material, which is available to authorized users.