A lard-rich high-fat diet increases hepatic peroxisome proliferator-activated receptors in endotoxemic rats

β-Sitosterol Reduces the Content of Triglyceride and Cholesterol in a High-Fat Diet-Induced Non-Alcoholic Fatty Liver Disease Zebrafish (Danio rerio) Model

OBJECTIVE

Non-alcoholic fatty liver disease (NAFLD) is strongly associated with hyperlipidemia, which is closely related to high levels of sugar and fat. β-sitosterol is a natural product with significant hypolipidemic and cholesterol-lowering effects. However, the underlying mechanism of its action on aquatic products is not completely understood.

METHODS

A high-fat diet (HFD)-induced NAFLD zebrafish model was successfully established, and the anti-hyperlipidemic effect and potential mechanism of β-sitosterol were studied using oil red O staining, filipin staining, and lipid metabolomics.

RESULTS

β-sitosterol significantly reduced the accumulation of triglyceride, glucose, and cholesterol in the zebrafish model. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that differential lipid molecules in β-sitosterol mainly regulated the lipid metabolism and signal transduction function of the zebrafish model. β-sitosterol mainly affected steroid biosynthesis and steroid hormone biosynthesis in the zebrafish model. Compared with the HFD group, the addition of 500 mg/100 g of β-sitosterol significantly inhibited the expression of Ppar-γ and Rxr-α in the zebrafish model by at least 50% and 25%, respectively.

CONCLUSIONS

β-sitosterol can reduce lipid accumulation in the zebrafish model of NAFLD by regulating lipid metabolism and signal transduction and inhibiting adipogenesis and lipid storage.

Lipopolysaccharide and the gut microbiota: Considering structural variation

Systemic inflammation is associated with chronic disease and is purported to be a main pathogenic mechanism underlying metabolic conditions. Microbes harbored in the host gastrointestinal tract release signaling byproducts from their cell wall, such as lipopolysaccharides (LPS), which can act locally and, after crossing the gut barrier and entering circulation, also systemically. Defined as metabolic endotoxemia, elevated concentrations of LPS in circulation are associated with metabolic conditions and chronic disease. As such, measurement of LPS is highly prevalent in animal and human research investigating these states. Indeed, LPS can be a potent stimulant of host immunity but this response depends on the microbial species' origin, a parameter often overlooked in both preclinical and clinical investigations. Indeed, the lipid A portion of LPS is mutable and comprises the main virulence and endotoxic component, thus contributing to the structural and functional diversity among LPSs from microbial species. In this review, we discuss how such structural differences in LPS can induce differential immunological responses in the host.

Maternal consumption of ɷ3 attenuates metabolic disruption elicited by saturated fatty acids-enriched diet in offspring rats

BACKGROUND AND AIMS

High-fat diet (HFD) intake during gestation and lactation has been associated with an increased risk of developing cardiometabolic disorders in adult offspring. We investigated whether metabolic alterations resulting from the maternal consumption of HFD are prevented by the addition of omega-3 (ɷ3) in the diet.

METHODS AND RESULTS

Wistar rat dams were fed a control (C: 19% of lipids and ɷ6:ɷ3 = 12), HF (HF: 33% lipids and ɷ6:ɷ3 = 21), or HF enriched with ɷ3 (HFω3: 33% lipids and ɷ6:ɷ3 = 9) diet during gestation and lactation, and their offspring food consumption, murinometric measurements, serum levels of metabolic markers, insulin and pyruvate sensitivity tests were evaluated. The maternal HFD increased body weight at birth, dyslipidemia, and elevated fasting glucose levels in the HF group. The enrichment of ɷ3 in the maternal HFD led to lower birth weight and improved lipid, glycemic, and transaminase biochemical profile of the HFω3 group until the beginning of adulthood. However, at later adulthood of the offspring, there was no improvement in these biochemical parameters.

CONCLUSION

Our findings show the maternal consumption of high-fat ɷ3-rich diet is able to attenuate or prevent metabolic disruption elicited by HFD in offspring until 90 days old, but not in the long term, as observed at 300 days old of the offspring.

Novel Organic Mineral Complex Prevents High-Fat Diet-Induced Changes in the Gut and Liver of Male Sprague-Dawley Rats

Diet-induced obesity and metabolic syndrome are associated with the onset of gastrointestinal diseases, such as hepatic steatosis and gut inflammation. Prior research shows that a proprietary soil-derived organic mineral complex (OMC) prevents hyperglycemia, endotoxemia, and liver injury in rats fed a high-fat diet (HFD) for 10 weeks. The aim of this study was to further examine the effects of OMC on the liver and gastrointestinal health of these rats. Six-week-old male Sprague-Dawley rats (n = 36) were divided into two dietary groups: Chow or HFD fed for 10 weeks. Animals were further divided (n = 6/group) and administered 0, 0.6, or 3.0 mg/mL OMC in their drinking water. The 10-week HFD resulted in significant liver fat accumulation. Both OMC doses prevented hepatic increases in the glycation end product Nε-(carboxymethyl)lysine (CML) induced by HFD (p < 0.05). Low-dose OMC was associated with higher expression of occludin in the small intestine of rats fed either diet (two-way ANOVA, p < 0.042). Linear discriminant analysis (LDA) effect size (LEfSe) indicated significant differences in fecal microbial composition of untreated HFD-fed rats in comparison to untreated Chow rats at 10 weeks (LDA score > 2.0 : 18). After 10 weeks, untreated HFD-fed rats were also more abundant in bacteria associated with obesity and metabolic disease in comparison to corresponding week 0 samples (LDA score > 2.0 : 31), 10-week untreated Chow (LDA > 2.0 : 18), or 10-week OMC-treated HFD-fed rats (0.6 mg/mL; LDA > 2.0 : 80, 3.0 mg/mL; LDA > 2.0 : 8). Low-dose OMC prevented the HFD-induced increase in the Firmicutes-to-Bacteroidetes (F/B) ratio (p < 0.0416). Study animals treated with OMC exhibited no significant changes in the gut microbiota at week 10, although gut inflammatory biomarkers were not significantly altered by diet or OMC treatment. These results indicate that OMC supplementation ameliorates glycosylation reactions and modifies HFD-induced alterations in the intestinal microbiota.

Interleukin-18 levels and mouse Leydig cell apoptosis during lipopolysaccharide-induced acute inflammatory conditions

Interleukin (IL)-18 is an inflammasome-mediated cytokine produced by germ cells, Leydig cells, and resident macrophages that is indispensable in the maintenance of homeostasis in the testis. We previously demonstrated that endogenous IL-18 induces testicular germ cell apoptosis during acute inflammation when plasma IL-18 levels are very high. However, the impact of acute inflammation and IL-18 on Leydig cells remained unclear. TM3 cells, a mouse Leydig cell line, and RAW264.7 cells, a mouse macrophage cell line, were stimulated with lipopolysaccharide (LPS) or recombinant IL-18 (rIL-18). We assessed the expression of inflammatory cytokines, caspase cleavage, and markers of apoptotic pathways. In Leydig cells, caspase 3 cleavage was increased and death-receptor-mediated apoptotic pathways were activated after LPS stimulation. However, LPS stimulation did not increase IL-18 expression in the Leydig cell line. When high-dose rIL-18 was administered to the Leydig cell line to mimic levels seem after inflammation, rIL-18 upregulated Tnf-α mRNA, Fadd mRNA, and Fas protein, promoted cleavage of caspase-8 and caspase-3, and induced apoptosis. Low-dose rIL-18 did not stimulate apoptosis. To determine if the high level of IL-18 seen in the testes after inflammation was derived from immune cells, we examined IL-18 protein expression in a macrophage cell line, RAW264.7. In contrast to the TM3 cells, IL-18 was significantly increased in RAW264.7 cells after LPS stimulation. These results suggest that high-dose IL-18 derived from macrophages is harmful to Leydig cells. Reducing the overexpression of IL-18 could be a new therapeutic approach to prevent Leydig cell apoptosis as a result of acute inflammation.

Differential effects of Chinese high-fat dietary habits on lipid metabolism: mechanisms and health implications

Background

The traditional Chinese diet blends lard with vegetable oil, keeping the fatty acid balance intake ratio of saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids at nearly 1:1:1. However, the effects of a mixture of lard and vegetable oil on lipid metabolism have never been researched. In the present study, by simulating Chinese high-fat dietary habits, we explored the effects of a mixture of lard and vegetable oil on lipid metabolism.

Methods

We randomly assigned 50 male C57BL/6 J mice to 5 groups (10 in each group) and fed them lard, sunflower oil (SFO), soybean oil (SBO), lard blended with sunflower oil (L-SFO), or lard blended with soybean oil (L-SBO) for 12 weeks.

Results

We found that the final body weights of mice in the lard group were significantly higher than those of mice in the SFO and SBO groups. Body fat rate and volume of fat cell of the lard group were significantly higher than those of the SFO, SBO, and L-SBO groups. Liver triglyceride level of the lard group increased significantly compared to the other groups. Although body fat rate and liver triglyceride level in the SBO and SFO groups decreased compared to those in the other groups, the high-density lipoprotein cholesterol/low-density lipoprotein cholesterol ratio were also significantly decreased in the SBO and SFO groups.

Conclusions

We found that a lard diet induced accumulation of body fat, liver and serum lipids, which can increase the risk of obesity, non-alcoholic fatty acid liver disease, and atherosclerosis. The vegetable oil diet resulted in cholesterol metabolism disorders even though it did not lead to obesity. The mixed oil diet induced body fat accumulation, but did not cause lipid accumulation in the liver and serum. Thus, differential oil/fat diets have an impact on differential aspects in mouse lipid metabolism.

Graphical abstract

A novel organic mineral complex prevented high fat diet-induced hyperglycemia, endotoxemia, liver injury and endothelial dysfunction in young male Sprague-Dawley rats

The prevalence of metabolic syndrome (MetSyn) has risen 35% since 2012 and over two-thirds of Americans exhibit features characterizing this condition (obesity, dyslipidemia, hyperglycemia, insulin resistance and/or endothelial dysfunction). The aim of this study was to evaluate the effects of a novel dietary supplemental organic mineral complex (OMC) on these risk factors in a rodent model of MetSyn. Six-week old male Sprague-Dawley rats were fed either standard chow or a high-fat diet (HFD) composed of 60% kcal from fat for 10 weeks. Rats were also treated with OMC in their drinking water at either 0 mg/mL (control), 0.6 mg/mL, or 3.0 mg/mL. The HFD-treated rats exhibited significantly increased body mass (p<0.05), epididymal fat pad mass (p<0.001), waist circumference (p = 0.010), in addition to elevations in plasma endotoxins (p<0.001), ALT activity (p<0.001), fasting serum glucose (p = 0.025) and insulin concentrations (p = 0.009). OMC did not affect body weight or adiposity induced by the HFD. At the higher dose OMC significantly blunted HFD-induced hyperglycemia (p = 0.021), whereas both low and high doses of OMC prevented HFD-induced endotoxemia (p = 0.002 and <0.001, respectively) and hepatocyte injury (ALT activity, p<0.01). Despite evidence of oxidative stress (elevated urinary H2O2 p = 0.032) in HFD-fed rats, OMC exhibited no demonstrable antioxidative effect. Consistent with prior studies, mesenteric arteries from HFD rats had more uncoupled eNOS (p = 0.006) and iNOS protein expression (p = 0.027) in addition to impaired endothelium-dependent vasodilation that was abrogated by the high dose of OMC (p<0.05). This effect of OMC may be attributed to the high nitrate content of the supplement. These findings suggest that the OMC supplement, particularly at the higher dose, ameliorated several risk factors associated with MetSyn via a non-antioxidant-dependent mechanism.

Composition of a maternal high fat diet rich in satured fats and omega 3 in gestation and lactation for studies with rodents

ABSTRACT Objective To prepare a high fat diet rich in satured fatty acids and supplemented with omega 3 for experimental studies in rodents. Methods Purified industrial ingredients and flaxseed oil as a source of omega 3 at a concentration of 3.5% (v/w) were used in the elaboration of the diets. Centesimal and nutritional compositions, fatty acids profile and dietary intake were evaluated. Serum levels of total protein, albumin, cholesterol and glucose in pregnant rats were verified. The offspring were assessed with regard to body mass and waist circumference. Statistical analysis was performed using the Kolmogorov-Smirnov, Anova One-Way test and Bonferroni post-test. Results High fat and high fat with omega 3 diets presented, respectively, 37% and 36% saturated fat, and the lipid amount was 80% higher than the American Institute of Nutrition 93G control diet. The omega 3 content was 50% higher in the high fat with omega 3 diet. There was no difference in consumption of diet types in weight (grams). The dams that received the High fat diet developed hypercholesterolemia and their High fat offspring exhibited higher body mass on the 1st day of life and increased abdominal circumference on the 30th day of life compared to the control and the high fat with omega 3 offspring. Conclusion The formulated diets with a higher amount of saturated fatty acids meet the nutritional requirements of the gestation and lactation period. The high fat diet with omega 3 was able to attenuate the changes observed in dams and their offspring.

Overweight and diabetes prevention: is a low-carbohydrate-high-fat diet recommendable?

In the past, different types of diet with a generally low-carbohydrate content (< 50–< 20 g/day) have been promoted, for weight loss and diabetes, and the effectiveness of a very low dietary carbohydrate content has always been a matter of debate. A significant reduction in the amount of carbohydrates in the diet is usually accompanied by an increase in the amount of fat and to a lesser extent, also protein. Accordingly, using the term “low carb–high fat” (LCHF) diet is most appropriate. Low/very low intakes of carbohydrate food sources may impact on overall diet quality and long-term effects of such drastic diet changes remain at present unknown. This narrative review highlights recent metabolic and clinical outcomes of studies as well as practical feasibility of low LCHF diets. A few relevant observations are as follows: (1) any diet type resulting in reduced energy intake will result in weight loss and related favorable metabolic and functional changes; (2) short-term LCHF studies show both favorable and less desirable effects; (3) sustained adherence to a ketogenic LCHF diet appears to be difficult. A non-ketogenic diet supplying 100–150 g carbohydrate/day, under good control, may be more practical. (4) There is lack of data supporting long-term efficacy, safety and health benefits of LCHF diets. Any recommendation should be judged in this light. (5) Lifestyle intervention in people at high risk of developing type 2 diabetes, while maintaining a relative carbohydrate-rich diet, results in long-term prevention of progression to type 2 diabetes and is generally seen as safe.