Supplementation of Medium-Chain Triglycerides Combined with Docosahexaenoic Acid Inhibits Amyloid Beta Protein Deposition by Improving Brain Glucose Metabolism in APP/PS1 Mice.

The deterioration of brain glucose metabolism predates the clinical onset of Alzheimer's disease (AD). Medium-chain triglycerides (MCTs) and docosahexaenoic acid (DHA) positively improve brain glucose metabolism and decrease the expression of AD-related proteins. However, the effects of the combined intervention are unclear. The present study explored the effects of the supplementation of MCTs combined with DHA in improving brain glucose metabolism and decreasing AD-related protein expression levels in APP/PS1 mice. The mice were assigned into four dietary treatment groups: the control group, MCTs group, DHA group, and MCTs + DHA group. The corresponding diet of the respective groups was fed to mice from the age of 3 to 11 months. The results showed that the supplementation of MCTs combined with DHA could increase serum octanoic acid (C8:0), decanoic acid (C10:0), DHA, and ß-hydroxybutyrate (ß-HB) levels; improve glucose metabolism; and reduce nerve cell apoptosis in the brain. Moreover, it also aided with decreasing the expression levels of amyloid beta protein (Aß), amyloid precursor protein (APP), ß-site APP cleaving enzyme-1 (BACE1), and presenilin-1 (PS1) in the brain. Furthermore, the supplementation of MCTs + DHA was significantly more beneficial than that of MCTs or DHA alone. In conclusion, the supplementation of MCTs combined with DHA could improve energy metabolism in the brain of APP/PS1 mice, thus decreasing nerve cell apoptosis and inhibiting the expression of Aß.

Long-term dietary folic acid supplementation attenuated aging-induced hippocampus atrophy and promoted glucose uptake in 25-month-old rats with cognitive decline.

The brain has high energy demand making it sensitive to changes in energy fuel supply. Aging shrinks brain volume, decreases glucose uptake availability of the brain, and finally, causes cognitive dysfunction. Folic acid supplementation delayed cognitive decline and neurodegeneration. However, whether folic acid affects brain energy metabolism and structural changes is unclear. The study aimed to determine if long-term dietary folic acid supplementation could alleviate age-related cognitive decline by attenuating hippocampus atrophy and promoting brain glucose uptake in Sprague-Dawley (SD) rats. According to folic acid levels in diet, 3-months old male SD rats were randomly divided into four intervention groups for 22 months in equal numbers: folic acid-deficient diet (FA-D) group, folic acid-normal diet (FA-N) group, low folic acid-supplemented diet (FA-L) group, and high folic acid-supplemented diet (FA-H) group. The results showed that serum folate concentrations decreased and serum homocysteine (Hcy) concentrations increased with age, and dietary folic acid supplementation increased serum folate concentrations and decreased Hcy concentrations at 11, 18, and 22 months of intervention. Dietary folic acid supplementation attenuated aging-induced hippocampus atrophy, which was showed by higher fractional anisotropy and lower mean diffusivity in the hippocampus, increased brain 18F-Fluorodeoxyglucose (18F-FDG) uptake, then stimulated neuronal survival, and alleviated age-related cognitive decline in SD rats. In conclusion, long-term dietary folic acid supplementation alleviated age-related cognitive decline by attenuating hippocampus atrophy and promoting brain glucose uptake in SD rats.

Folic Acid Inhibits Aging-Induced Telomere Attrition and Apoptosis in Astrocytes In Vivo and In Vitro.

Folic acid (FA) has been reported to inhibit astrocyte apoptosis and improve aging-induced disorders; however, its role in telomere attrition remains unclear. In present study, 4-month-old senescence-accelerated mouse prone 8 (SAMP8) mice were assigned to four treatment groups for the in vivo experiment: FA-deficient diet (FA-D) group, FA-normal diet (FA-N) group, low FA-supplemented diet (FA-L) group, and high FA-supplemented diet (FA-H) group. These mice were euthanized when 10 months old. There was also a young SAMP8 (4 months old) control group (Con-Y) fed with FA-normal diet. In in vitro study, primary cultures of astrocytes from hippocampus and cerebral cortex were incubated for five generations with various concentrations of FA (0-40 µM) and were assigned to five groups: FA 0 µM (generation 5), FA 10 µM (generation 5), FA 20 µM (generation 5), FA 40 µM (generation 5), and FA 10 µM (generation 1). The results showed that FA supplementation inhibited aging-induced astrocytosis, astrocyte apoptosis, neurodegeneration, and prevented telomere attrition in hippocampus and cortex of SAMP8 mice. FA supplementation also decreased apoptosis and telomere attrition, and increased telomerase activity, in primary cultures of astrocytes. These results showed that it may be one of the mechanisms that FA inhibiting aging-induced apoptosis of astrocyte by alleviating telomere attrition.

Antihyperlipidemic and Hepatoprotective Properties of Vitamin B6 Supplementation in Rats with High-Fat Diet-Induced Hyperlipidemia.

BACKGROUND: The incidence and mortality of hyperlipidemia are increasing year by year, showing a younger trend. At present, the treatment of hyperlipidemia is mainly dependent on western medicine, but its side effects on liver and kidney function are common in clinics. Therefore, it is necessary to study the treatment of hyperlipidemia by augmenting effective dietary nutrition supplements. Vitamin B6 (VitB6), as an essential cofactor for enzymes, participates in lipid metabolism. The effects of VitB6 on hyperlipidemia, however, have not been reported until now. AIM: The present study was to investigate the influence of VitB6 on hepatic lipid metabolism in hyperlipidaemia rats induced by a High-Fat Diet (HFD). METHODS: Male Sprague-Dawley rats were kept on HFD for two weeks to establish the hyperlipidemia model. The rats in low-dosage and high-dosage groups were received 2.00 and 3.00 mg/kg/- day of VitB6 for eight weeks, respectively. RESULTS: The results showed that both doses of VitB6 reduced HFD-induced hepatic Low-Density Lipoprotein Cholesterol (LDL-C); decreased blood cholesterol (TC), triglycerides, LDL-C, atherogenic index (AI), Atherogenic Index of Plasma (AIP), apolipoprotein B (ApoB) and ApoB/apolipoprotein A-1(ApoA1) ratio; increased liver High-Density Lipoprotein Cholesterol (HDL-C) and serum ApoA1; reduced hepatic steatosis and triglyceride accumulation, lowered fat storage, and recovered heart/body and brain/body ratio to a normal level. In addition, VitB6 supplementation markedly decreased HMGR level, increased the mRNA abundance of LDLR and CYP7A1, and protein expression of SIRT1, following the downregulation of SREBP-1 and PPARγ protein expression in the liver of hyperlipidemia rats. CONCLUSION: In summary, oral VitB6 supplementation can ameliorate HFD-induced hepatic lipid accumulation and dyslipidemia in SD rats by inhibiting fatty acid and cholesterol synthesis, promoting fatty acid decomposition and cholesterol transport.

Effects of oral selenium and magnesium co-supplementation on lipid metabolism, antioxidative status, histopathological lesions, and related gene expression in rats fed a high-fat diet.

BACKGROUND: Supplementation with Selenium (Se) has been shown to lower blood cholesterol and increase tissue concentrations of the antioxidant glutathione (GSH); however, the effects of Se supplementation, in combination with supplemental magnesium, on high fat-induced hyperlipidemia have not been studied. This study was designed to elucidate the effects of oral selenium and magnesium co-supplementation on antihyperlipidemic and hepatoprotective, antioxidative activities, and related gene expression in a hyperlipidemic rat model. METHODS: Forty male Sprague Dawley rats were divided into 4 groups: one group served as control group (CT), provided control diet; The other groups were made hyperlipidemic with high-fat diet; specifically, a high-fat diet group (HF); low-dose selenium (0.05 mg/kg·bw) + low-dose magnesium (5.83 mg/kg·bw) supplement high-fat diet group (HF + LSe + LMg) and high-dose selenium (0.10 mg/kg·bw) + high-dose magnesium (58.33 mg/kg·bw) supplement high-fat diet group (HF + HSe + HMg). The first 4 weeks of the experiment was a hyperlipidemia inducing period using high-fat diet and the following 8 weeks involved in selenium and magnesium co-supplementation. On day 0, 20, 40 and 60 of the intervention, lipid profile was measured. At the end of the 12-week experiments, final blood and liver samples were collected for the measurements of lipid profile, antioxidative indexes, pathological examination, and liver lipid metabolism related gene expression. RESULTS: The elevated levels of serum and liver total cholesterol (TC) and serum LDL-C induced by feeding high-fat diets were significantly reduced by low-dose Se and Mg co-supplementation. Both doses of selenium and magnesium co-supplementation notably decreased the blood and liver TG levels, liver function indexes ALT and AST and the ratio of TC/HDL-C and TG/HDL-C. In contrast, Se and Mg supplementation showed a substantial increase in Se-dependent glutathione peroxidase (GSH-Px) and SOD activities and an significant reduce of level of MDA of hyperlipidemic rats. Oil Red O staining showed that selenium and magnesium co-supplementation significantly reduced hepatic intracellular triacylglycerol accumulation. H&E staining also showed that selenium and magnesium co-supplementation can attenuate liver steatosis. Selenium and magnesium co-supplementation remarkably inhibited the mRNA expression level of hepatic lipogenesis genes liver X receptor alpha (LXRα),SREBP-1c and FASN (fatty acid synthase), regulated the mRNA expression levels of liver enzymes related to cholesterol metabolism, including the down regulation of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) and the upregulation of cholesterol 7α-hydroxylase (CYP7A1) and lecithin cholesterol acyltransferase (LCAT) in the liver of hyperlipidemia rats. CONCLUSIONS: Oral selenium and magnesium co-supplementation inhibited an increase of lipid and liver profile and liver function index induced by a high-fat diet, and enhanced the activity of the antioxidant enzymes. Selenium combined with magnesium is a promising therapeutic strategy with lipid-lowering and antioxidative effects that protects the liver against hyperlipidemia.

Effect of magnesium gluconate administration on lipid metabolism, antioxidative status, and related gene expression in rats fed a high-fat diet.

To explore the effect of magnesium gluconate (MgG) on lipid metabolism and its regulation mechanism through animal experiments, and to provide basis for MgG dietary intervention in hyperlipidemia. The first four weeks was hyperlipidemia-inducing period through high-fat diet and the following eight weeks was the MgG supplementation. At the end of the experiment, blood and liver samples were collected for the measurements of lipid profile, antioxidative indexes, pathological examination, and cholesterol metabolism-related gene expression. Oral administration of MgG notably decreased the blood levels of TC, TG, LDL-C and liver function index ALT and AST of hyperlipidemic rats. The rats supplemented with magnesium showed a huge increase in the GSH-Px and SOD activities, and reduced the heart weight and liver lipid accumulation of high-fat diet fed rats. MgG remarkably up-regulated the mRNA expression levels of LDLR and CYP7A1 of liver enzymes related to cholesterol metabolism. Oral magnesium supplementation inhibited an increase in lipid profile and liver function index by a high-fat diet, and enhanced the activity of the antioxidant enzymes. Magnesium has lipid-lowering and antioxidative effects that protect the liver against hyperlipidemia.