Dietary Supplementation with Sodium Butyrate Reduces High-sucrose Diet-induced Hepatic Accumulation of Triacylglycerols and Expression of Fatty Acid Synthesis Enzymes in Rats.

We investigated the effects of dietary supplementation with sodium butyrate (NaB) on the lipid levels, gene expression, and proteins related to lipid metabolism in nonalcoholic fatty liver disease (NAFLD) rat models fed a high-sucrose diet for 3 weeks. Supplementation with 1% and 3% NaB reduced high-sucrose-induced hepatic triacylglycerol levels and expression of genes and proteins related to fatty acid synthesis, such as fatty acid synthase and malic enzyme, in a dose-dependent manner. NaB supplementation did not affect hepatic cholesterol levels or expression of genes related to ß-oxidation. NaB may prevent high-sucrose-induced NAFLD by repressing the fatty acid synthesis pathway.

Effects of Dietary Supplementation with Myo-inositol on Hepatic Expression of Glycolytic and Fructolytic Enzyme Genes in Rats Fed a High-sucrose Diet.

We examined effects of a major lipotrope, myo-inositol, on the expression of primary glycolytic (glucokinase and phosphofructokinase) and fructolytic enzyme (ketohexokinase [KHK] and aldolase B) genes in the livers of rats fed a control diet, high-sucrose diet, or high-sucrose diet supplemented with 0.5% myo-inositol for 14 d. Supplementation with myo-inositol decreased the hepatic expression of fructolytic enzyme genes, but not that of glycolytic enzyme genes, and the levels of triglycerides, fatty acid synthase, and KHK proteins in high-sucrose diet-induced fatty liver. The study results suggest that myo-inositol represses primary fructlysis, but not glycolysis, in high-sucrose diet-induced fatty liver.

Dietary supplementation with myo-inositol reduces high-fructose diet-induced hepatic ChREBP binding and acetylation of histones H3 and H4 on the Elovl6 gene in rats.

ELOVL fatty acid elongase 6 (ELOVL6) is a long-chain fatty acid elongase, and the hepatic expression of the Elovl6 gene and accumulation of triglycerides (TG) are enhanced by long-term high-fructose intake. Fatty acid synthesis genes, including Elovl6, are regulated by lipogenic transcription factors, sterol regulatory element-binding protein 1c (SREBP-1c) and carbohydrate-responsive element-binding protein (ChREBP). In addition, carbohydrate signals induce the expression of fatty acid synthase not only via these transcription factors but also via histone acetylation. Since a major lipotrope, myo-inositol (MI), can repress short-term high-fructose-induced fatty liver and the expression of fatty acid synthesis genes, we hypothesized that MI might influence SREBP-1c, ChREBP, and histone acetylation of Elovl6 in fatty liver induced by even short-term high-fructose intake. This study aimed to investigate whether dietary supplementation with MI affects Elovl6 expression, SREBP-1 and ChREBP binding, and acetylation of histones H3 and H4 at the Elovl6 promoter in short-term high-fructose diet-induced fatty liver in rats. Rats were fed a control diet, high-fructose diet, or high-fructose diet supplemented with 0.5% MI for 10 days. This study showed that MI supplementation reduced short-term high-fructose diet-induced hepatic expression of the Elovl6 gene, ChREBP binding, but not SREBP-1 binding, and acetylation of histones H3 and H4 at the Elovl6 promoter.

Maltobionic acid accelerates recovery from iron deficiency-induced anemia in rats.

In experiments 1 and 2, effect of ingestion of maltobionic acid calcium salt (MBCa) on recovery of rats from a latent iron deficiency and from iron deficiency anemia was examined, respectively. After grouping rats into control and iron-deficiency groups, a latent iron deficiency or iron-deficiency anemia was induced in the latter group. And recovery from these states by MBCa containing diets (0%, 3%, and 6% MBCa in diet, classified into MBCa-0, MBCa-3, and MBCa-6 groups) was compared for convalescence period in light of iron sufficient control group. In experiment 1, MBCa ingestion significantly increased the iron concentration in the serum and liver, and promoted recovery from a latent iron deficiency. In experiment 2, hemoglobin and hematocrit levels increased significantly with MBCa intake, and recovery from iron-deficiency anemia was promoted. MBCa effectively promoted the recovery of rats from a subclinical iron deficiency and iron-deficiency anemia.Abbreviations: ANOVA: analysis of variance; DMT1: divalent metal transporter 1; EDTA-2Na: disodium salt of ethylenediaminetetraacetic acid; Fpn: feroportin; Hb: hemoglobin; Ht: hematocrit; ICP-OES: inductivity coupled plasma optical emission spectrometer; MBCa: maltobionic acid calcium salt; nitroso-PSAP: 2-nitroso-5-[N-n-propyl-N-(3-sulfopropyl)amino]phenol; SE: standard error; SI: serum-iron concentration; TSAT: transferrin saturation; TIBC: total iron-binding capacity; UIBC: unsaturated iron-binding capacity.

Treatment with myo-inositol attenuates binding of the carbohydrate-responsive element-binding protein to the ChREBP-ß and FASN genes in rat nonalcoholic fatty liver induced by high-fructose diet.

Dietary supplementation with the major lipotrope myo-inositol (MI) potently reduces triglyceride (TG) content and expression levels of the fatty acid synthesis genes, for example, fatty acid synthase (FASN), in rat nonalcoholic fatty liver induced by high-fructose diet. Fatty acid synthesis genes are regulated by the carbohydrate-responsive element-binding protein (ChREBP) that exists in 2 isoforms: ChREBP-α and ChREBP-ß. The gene encoding the latter isoform is more responsive to fructose. Because MI repressed the induction of fatty acid synthesis gene expression by high-fructose diet, we hypothesized that MI may reduce binding of ChREBP to the carbohydrate response elements (ChoREs) in the ChREBP-ß gene as well as in fatty acid synthesis genes in the liver. Rats were fed high-glucose, high-fructose, or high-fructose diets supplemented with MI (0.05% and 0.25%) for 2 weeks. Hepatic TG content and expression levels of the glucose-6-phosphate dehydrogenase, malic enzyme 1, FASN, acetyl-CoA carboxylase alpha, S14, and ChREBP-ß were remarkably elevated in rats fed with high fructose compared with the corresponding levels in high-glucose group. Notably, elevated values of these parameters in high-fructose group were reduced by MI. Similarly, high-fructose-induced ChREBP binding to the ChoREs of the ChREBP-ß and FASN genes was nominally decreased by MI. This study showed that treatment with MI reduced elevated TG content and expression of genes related to fatty acid synthesis, such as FASN and ChREBP-ß, in rat nonalcoholic fatty liver induced by high-fructose diet. Furthermore, MI treatment nominally decreased increased binding of ChREBP to the ChoREs of ChREBP-ß and FASN genes.

Dietary supplementation with myo-inositol reduces hepatic triglyceride accumulation and expression of both fructolytic and lipogenic genes in rats fed a high-fructose diet.

Excessive fructose ingestion drastically enhances hepatic lipid accumulation. The most prominent form of inositol-myo-inositol (MI)-remarkably reduces high sucrose-induced hepatic triglyceride (TG) accumulation. Because MI is a major and strong lipotrope, we hypothesized in this study that MI improves fatty liver more induced by excessive ingestion of fructose than sucrose. Rats were fed a high-glucose diet (HGD), a high-fructose diet (HFD), or an HFD supplemented with 0.2% MI for 12 days. Hepatic levels of TG and mRNAs for fructolysis (ketohexokinase and aldolase B), lipogenesis (pyruvate kinase, liver, and RBC; glucose-6-phosphate dehydrogenase; acetyl-CoA carboxylase alpha; fatty acid synthase; and stearoyl-CoA desaturase 1), and a key transcription factor for lipogenesis-carbohydrate-responsive element-binding protein-were significantly increased in the HFD group compared with the HGD group, and the increase was markedly decreased by MI supplementation. Similarly, HFD-induced pyruvate kinase, liver, and RBC and fatty acid synthase protein levels in the liver were reduced by MI treatment. On the other hand, hepatic levels of mRNAs for ß-oxidation (acyl-CoA synthetase and carnitine palmitoyltransferase 1a) did not differ among the 3 groups. Taken together, this study showed that MI supplementation decreases the expression of fructolytic/lipogenic genes and lipogenic proteins as well as TG accumulation in high fructose-induced fatty liver in rats.

Synthesis of oolongtheanins and their inhibitory activity on micellar cholesterol solubility in vitro.

The synthesis of oolongtheanins (1a-d) was accomplished from EGC and/or EGCg in three steps. Oolongtheanin-3'-O-gallate (1b) showed more potent inhibitory activity on micellar cholesterol solubility than did EGCg.

Dietary supplementation with alpha-amylase inhibitor wheat albumin to high-fat diet-induced insulin-resistant rats is associated with increased expression of genes related to fatty acid synthesis in adipose tissue.

It is well-known that insulin resistance induces lipid abnormalities by decreasing insulin actions in adipose tissue. This study examined the effects of inhibiting postprandial hyperglycemia/hyperinsulinemia, using the alpha-amylase inhibitor wheat albumin (WA), on the expression of genes related to fatty acid metabolism in the adipose tissue of high-fat diet-induced insulin-resistant rats. Postprandial glucose and insulin levels were significantly lower after oral starch loading with WA than with inactivated WA in insulin-resistant rats. In addition, the increases in the plasma triacylglycerol and insulin levels by feeding insulin-resistant rats a control diet were inhibited by WA supplementation. Supplementation with WA increased the mRNA levels of not only fatty acid synthase (FAS) and acyl-CoA carboxylase (ACC) but also their transcriptional factors such as carbohydrate response element-binding protein (ChREBP) and sterol regulatory element binding protein (SREBP)1 in the mesenteric adipose tissue of the insulin-resistant rats. In addition, supplementation with WA tended to increase the protein expression levels of FAS and ACCs. These results suggest that reductions in the plasma triacylglycerol and insulin levels by inhibiting hyperglycemia/hyperinsulinemia with the alpha-amylase inhibitor WA in high-fat diet-induced insulin-resistant rats are associated with increased expression of genes related to fatty acid synthesis and their transcriptional factors in adipose tissue.

(-)-Epigallocatechin gallate enhances the expression of genes related to insulin sensitivity and adipocyte differentiation in 3T3-L1 adipocytes at an early stage of differentiation.

OBJECTIVE: (-)-Epigallocatechin gallate (EGCG) is thought to enhance insulin sensitivity in adipocytes, although doses used in in vitro experiments have been shown to promote apoptosis. To explore the effects of EGCG on insulin sensitivity in adipocytes, the expression of genes related to insulin sensitivity and adipocyte differentiation in 3T3-L1 adipocytes were measured in response to low doses of EGCG. METHODS: Increasing concentrations of low-dose EGCG were administered for 8 d to differentiating 3T3 adipocytes, either at days 0-8 (early stage) or at days 8-16 (late stage). Fat accumulation and cell activity were measured by Oil Red O staining and 1-(4,5-dimethylthiazol-2-yl)-3,5-diphenylformazan assay, respectively. The expression of genes related to insulin sensitivity and adipocyte differentiation was measured by real-time reverse transcriptase-polymerase chain reaction. RESULTS: Fat accumulation and cell activity in 3T3-L1 cells at the early and late stages were reduced at EGCG concentrations > or = 50 microM. However, EGCG doses of 5-10 microM reduced fat accumulation and induced the expression of genes related to insulin sensitivity (including Fabp4, Cd36, Lpl, Pck1, Acox1, Lypla3, and Ucp2) and adipocyte differentiation (Pparg1, Pparg2, Cebps, and Ppargc1a). These increases were only seen at the early, and not late, stages of differentiation. CONCLUSION: These data indicate that low doses of EGCG, despite reducing triacylglycerol accumulation, induce the expression of genes related to insulin sensitivity in the early stage of differentiation.

Dietary supplementation with epigallocatechin gallate elevates levels of circulating adiponectin in non-obese type-2 diabetic Goto-Kakizaki rats.

Epigallocatechin gallate (EGCG) reportedly enhances plasma adiponectin levels in models of insulin resistance and obesity. In this study, we found that EGCG increases plasma adiponectin levels and decreases plasma triacylglycerol levels in non-obese diabetic Goto-Kakizaki rats with insulin secretory dysfunction. These results suggest that EGCG ameliorates lipid metabolic abnormality even in non-obese rats, probably by increasing adiponectin production.