Boosting the Ferroptotic Antitumor Efficacy via Site-Specific Amplification of Tailored Lipid Peroxidation.

Ferroptosis is an iron-dependent cell death pathway that can eradicate certain apoptosis-insensitive cancer cells. The ferroptosis-inducing molecules are tailored lipid peroxides whose efficacy is compromised in hypoxic solid tumor and lack of tumor selectivity. It has been demonstrated that ascorbate (Asc) in pharmacological concentrations can selectively kill cancer cells via accumulating hydrogen peroxide (H2O2) only in tumor extracellular fluids. It was hypothesized that Asc-induced, selective enrichment of H2O2 in tumor coupled with Fe3+ codelivery could simultaneously address the above two problems via boosting the levels of hydroxyl radicals and oxygen in the tumor site to ease peroxidation initiation and propagation, respectively. The aim of this work was to synergize the action of Asc with lipid-coated calcium phosphate (CaP) hybrid nanocarrier that can concurrently load polar Fe3+ and nonpolar RSL3, a ferroptosis inducer with the mechanism of inhibiting lipid peroxide repair enzyme (GPX4). The hybrid nanocarriers showed accelerated cargo release at acidic conditions (pH 5.0). The combinational approach (Asc plus nanocarrier) produced significantly elevated levels of hydroxyl radicals, lipid peroxides, and depleted glutathione under hypoxia, which was accompanied with the strong cytotoxicity (IC50 = 1.2 ± 0.2 µM) in the model 4 T1 cells. In the 4 T1 tumor-bearing xenograft mouse model, the intravenous nanocarrier delivery plus intraperitoneal Asc administration resulted in a superior antitumor performance in terms of tumor suppression, which did not produce supplementary adverse effects to the healthy organs. This work provides a novel approach to enhance the potency of ferroptotic nanomedicine against solid tumors without inducing additional side effects.

Dihydromyricetin Ameliorates Nonalcoholic Fatty Liver Disease by Improving Mitochondrial Respiratory Capacity and Redox Homeostasis Through Modulation of SIRT3 Signaling.

Aims: Our previous clinical trial indicated that the flavonoid dihydromyricetin (DHM) could improve hepatic steatosis in patients with nonalcoholic fatty liver disease (NAFLD), altough the potential mechanisms of these effects remained elusive. Here, we investigated the hepatoprotective role of DHM on high-fat diet (HFD)-induced NAFLD. Results: DHM supplementation could effectively ameliorate the development of NAFLD by inhibiting hepatic lipid accumulation both in HFD-fed wild-type mice and in palmitic acid-induced hepatocytes. We reveal for the first time that mitochondrial dysfunction characterized by ATP depletion and augmented oxidative stress could be reversed by DHM treatment. Moreover, DHM enhanced the mitochondrial respiratory capacity by increasing the expression and enzymatic activities of mitochondrial complexes and increased mitochondrial reactive oxygen species scavenging by restoring manganese superoxide dismutase (SOD2) activity. Interestingly, the benefits of DHM were abrogated in SIRT3 knockout (SIRT3KO) mice and in hepatocytes transfected with SIRT3 siRNA or treated with an SIRT3-specific inhibitor. We further showed that DHM could increase SIRT3 expression by activating the adenosine monophosphate-activated protein kinase (AMPK)-peroxisome proliferator-activated receptor-γ coactivator-1 alpha (PGC1α)/estrogen-related receptor-α (ERRα) signaling pathway. Innovation: Our work indicates that SIRT3 plays a critical role in the DHM-mediated beneficial effects that include ameliorating mitochondrial dysfunction and oxidative stress in a nutritional NAFLD model both in vivo and in vitro.Conclusion: Our results suggest that DHM prevents NAFLD by improving mitochondrial respiratory capacity and redox homeostasis in hepatocytes through a SIRT3-dependent mechanism. These results could provide a foundation to identify new DHM-based preventive and therapeutic strategies for NAFLD.

Effect of combined use of a low-carbohydrate, high-protein diet with omega-3 polyunsaturated fatty acid supplementation on glycemic control in newly diagnosed type 2 diabetes: a randomized, double-blind, parallel-controlled trial.

Background: The combined effect of a low-carbohydrate, high-protein (LCHP) diet and omega-3 (n-3) polyunsaturated fatty acid (PUFA) supplementation on patients with type 2 diabetes (T2D) is not known. Objective: The aim of this study was to evaluate the effect of an LCHP diet combined with ω-3 (LCHP+ω-3) on glycemic control in patients with T2D. Design: In this randomized, double-blind, parallel-controlled trial, 122 newly diagnosed participants with T2D were randomly assigned to receive a high-carbohydrate, low-protein diet with low ω-3 PUFAs [control (CON)], an LCHP, ω-3, or LCHP+ω-3 diet for 12 wk. The ratio of carbohydrate to protein was 42:28 in the LCHP and LCHP+ω-3 diet and 54:17 in the CON and ω-3 diet. The participants were given 6 g fish oil/d (containing 3.65 g docosahexaenoic acid, eicosapentaenoic acid, and docosapentaenoic acid/d) in the ω-3 and LCHP+ω-3 diet groups or 6 g corn oil/d (placebo) in the CON and LCHP diet groups. Results: Compared with the CON diet group, greater decreases in glycated hemoglobin (HbA1c) and fasting glucose were observed in all of the other 3 diet groups at 12 wk. Of note, HbA1c reduction in the LCHP+ω-3 diet group (-0.51%; 95% CI: -0.64%, -0.37%) was greater than that in the LCHP (P = 0.03) and ω-3 (P = 0.01) diet groups at 12 wk. In terms of fasting glucose, only the LCHP+ω-3 diet group showed a significant decrease at 4 wk (P = 0.03 compared with CON). Moreover, the reduction in fasting glucose in the LCHP+ω-3 diet group (-1.32 mmol/L; 95% CI: -1.72, -0.93 mmol/L) was greater than that in the LCHP (P = 0.04) and ω-3 (P = 0.03) diet groups at 12 wk. Conclusions: The LCHP+ω-3 diet provided greater effects on HbA1c and fasting glucose and faster effects on fasting glucose than both the LCHP and ω-3 diets, indicating the potential necessity of combining an LCHP diet with ω-3 PUFAs in T2D control. This trial was registered at chictr.org.cn/ as ChiCTR-TRC-14004704.

All-active antitumor micelles via triggered lipid peroxidation.

Traditional antitumor nanomedicines have been suffering from the poor tumor targeting (ca. 1%) by the enhanced permeability and retention (EPR) effect, and the low drug loading (<5%). It was postulated that engineering all-active nanoplatform could increase the therapeutic efficacy to enable the nanocarrier function as both vehicle and active ingredient. To achieve this, a photosensitizer, Ce6 was encapsulated within polymeric micelles with unsaturated fatty acids as the building blocks. Upon light irradiation, the singlet oxygen produced by Ce6 induced lipid peroxidation, resulting in the generation of both active free radicals and aldehydes. These supplementary radicals could exert cytotoxic effect for direct killing tumor cells. The aldehyde end-products induced significant cell cycle arrest at G2 phase in 4T1 cells. The peroxidation process also facilitated the on-demand disassembly of micelles and rapid release of Ce6 to maximize the therapeutic effect of singlet oxygen. These all-active micelles showed a significantly enhanced cytotoxicity with the half maximal inhibitory concentration (IC50) of 0.6 ±â€¯0.2 µg/mL in contrast to the control micelles at 3.4 ±â€¯0.5 µg/mL. The improved antitumor efficacy of the all-active micelles was also demonstrated in the 4T1 tumor-bearing mice in vivo. The current work provides a facile approach to enhance the antitumor efficacy of PDT nanomedicine using the biocompatible fatty acids, which can be applied to various antitumor drugs and unsaturated lipids.

Capsaicin Supplementation Improved Risk Factors of Coronary Heart Disease in Individuals with Low HDL-C Levels.

Low high-density lipoprotein cholesterol (HDL-C) is associated with an increased risk of coronary heart disease (CHD). This study aimed to evaluate the effects of capsaicin intervention on the serum lipid profile in adults with low HDL-C. In a randomized, double-blind, controlled clinical trial, 42 eligible subjects were randomly assigned to the capsaicin (n = 21, 4 mg of capsaicin daily) or to the control group (n = 21, 0.05 mg of capsaicin daily) and consumed two capsaicin or control capsules, which contained the powder of the skin of different peppers, twice daily for three months. Thirty-five subjects completed the trial (18 in the capsaicin group and 17 in the control group). The baseline characteristics were similar between the two groups. Compared with the control group, fasting serum HDL-C levels significantly increased to 1.00 ± 0.13 mmol/L from 0.92 ± 0.13 mmol/L in the capsaicin group (p = 0.030), while levels of triglycerides and C-reactive protein and phospholipid transfer protein activity moderately decreased (all p < 0.05). Other lipids, apolipoproteins, glucose, and other parameters did not significantly change. In conclusion, capsaicin improved risk factors of CHD in individuals with low HDL-C and may contribute to the prevention and treatment of CHD.

Protective Effects of the Segmental Renal Artery Clamping Technique on Ischemia-Reperfusion Injury in db/db Diabetic Mice.

Renal ischemia-reperfusion (I/R) injury is inevitable in partial nephrectomy and other kidney surgeries, with a higher incidence in patients with renal insufficiency. This study aimed to investigate the protective effects of precise segmental renal artery clamping (SRAC) against renal I/R injury in db/db diabetic mice, compared with conventional renal artery clamping (RAC). Grape seed extract, a powerful free radical scavenger, was administered to diabetic mice for 4 weeks before operation in subgroups (30 mg/kg/d). The unilateral renal pedicle was ligatured, and I/R injury to the contralateral kidney was induced (ischemia for 30 min followed by reperfusion for 24 h). Blood glucose value, creatinine, blood urea nitrogen, and urine microalbumin/urine creatinine ratio increased gradually and showed no preoperative statistical differences among six subgroups. These parameters were significantly lower in the SRAC than in the RAC group 24 h postoperatively. Moreover, the nonischemic area in the SRAC group expressed less KIM-1 and TNF-α mRNA and also revealed minor histopathological damage induced by I/R. These findings suggest that SRAC effectively reduces early renal injury induced by I/R and accelerates the recovery of renal function in diabetic mice. Thus, SRAC may be an ideal technique in partial nephrectomy, especially for patients with diabetic nephropathy and other renal insufficiencies.

Capsaicin-containing chili improved postprandial hyperglycemia, hyperinsulinemia, and fasting lipid disorders in women with gestational diabetes mellitus and lowered the incidence of large-for-gestational-age newborns.

BACKGROUND & AIMS: Gestational diabetes mellitus (GDM) may increase the future health risks of women and their offspring. The aim of this study was to determine the effect of capsaicin supplementation on blood glucose, lipid metabolism and pregnancy outcomes in women with GDM. METHODS: Forty-four pregnant women with GDM at 22-33 gestational weeks were randomly assigned to the capsaicin group (5 mg/d of capsaicin) or to the placebo group (0 mg/d of capsaicin) for 4 weeks in a randomized, double-blind, placebo-controlled trial. The concentrations of fasting plasma glucose and serum insulin, 2-h postprandial plasma glucose (2-h PG) and serum insulin (2-h INS), and fasting serum lipids, liver and kidney function parameters, and calcitonin gene-related peptide (CGRP) were measured at 0 and 4 weeks. The maternal and neonatal outcomes were also recorded. RESULTS: Forty-two women completed the trial. Compared to the placebo group, 2-h PG and 2-h INS concentrations and 2-h postprandial HOMA-IR (2-h HOMA-IR) levels, and the fasting serum total cholesterol and triglycerides concentrations significantly decreased in the capsaicin group after treatment (P < 0.05). Moreover, the fasting serum apolipoprotein B and CGRP concentrations significantly increased in the capsaicin group (P < 0.05). The changes in the 2-h PG and 2-h INS concentrations and in the 2-h HOMA-IR were negatively correlated with the change in the serum CGRP concentration (P < 0.05). Furthermore, the incidence of large-for-gestational-age (LGA) newborns was significantly lower in the capsaicin group than in the placebo group (P = 0.022). CONCLUSIONS: Capsaicin-containing chili supplementation regularly improved postprandial hyperglycemia and hyperinsulinemia as well as fasting lipid metabolic disorders in women with GDM, and it decreased the incidence of LGA newborns.

Dihydromyricetin improves glucose and lipid metabolism and exerts anti-inflammatory effects in nonalcoholic fatty liver disease: A randomized controlled trial.

Ampelopsis grossedentata, a medicinal and edible plant, has been widely used in China for hundreds of years, and dihydromyricetin is the main active ingredient responsible for its various biological actions. We investigated the effects of dihydromyricetin on glucose and lipid metabolism, inflammatory mediators and several biomarkers in nonalcoholic fatty liver disease. In a double-blind clinical trial, sixty adult nonalcoholic fatty liver disease patients were randomly assigned to receive either two dihydromyricetin or two placebo capsules (150 mg) twice daily for three months. The serum levels of alanine, aspartate aminotransferase, γ-glutamyl transpeptidase, glucose, low-density lipoprotein-cholesterol and apolipoprotein B, and the homeostasis model assessment of insulin resistance (HOMA-IR) index were significantly decreased in the dihydromyricetin group compared with the placebo group. In the dihydromyricetin group, the serum levels of tumor necrosis factor-alpha, cytokeratin-18 fragment and fibroblast growth factor 21 were decreased, whereas the levels of serum adiponectin were increased at the end of the study. We conclude that dihydromyricetin supplementation improves glucose and lipid metabolism as well as various biochemical parameters in patients with nonalcoholic fatty liver disease, and the therapeutic effects of dihydromyricetin are likely attributable to improved insulin resistance and decreases in the serum levels of tumor necrosis factor-alpha, cytokeratin-18, and fibroblast growth factor 21.

Resveratrol improves hepatic steatosis by inducing autophagy through the cAMP signaling pathway.

SCOPE: Resveratrol (RSV), a natural polyphenol, has been reported to attenuate nonalcoholic fatty liver disease (NAFLD); however, its underlying mechanism is unclear. Autophagy was recently identified as a critical protective mechanism during NAFLD development. Therefore, we investigated the role of autophagy in the beneficial effects of RSV on hepatic steatosis. METHODS AND RESULTS: Via Oil red O staining, triglyceride, and ß-hydroxybutyrate detection, we found that RSV decreased palmitate-induced lipid accumulation and stimulated fatty acid ß-oxidation in hepatocytes. Based on Western blot assay, confocal microscopy and transmission electron microscopy, we found that RSV induced autophagy in hepatocytes, whereas autophagy inhibition markedly abolished RSV-mediated hepatic steatosis improvement. Moreover, RSV increased cAMP levels and the levels of SIRT1 (sirtuin 1), pPRKA (phosphorylated protein kinase A), and pAMPK (phosphorylated AMP-activated protein kinase), as well as SIRT1 activity in HepG2 cells. Incubation with inhibitors of AC (adenylyl cyclase), PRKA, AMPK, SIRT1, or with AC, PRKA, AMPK, or SIRT1 siRNA abolished RSV-mediated autophagy. Similar results were obtained in mice with hepatic steatosis. CONCLUSION: RSV improved hepatic steatosis partially by inducing autophagy via the cAMP-PRKA-AMPK-SIRT1 signaling pathway, which provides new evidence regarding RSV's effects on NAFLD treatment.

Daidzein supplementation decreases serum triglyceride and uric acid concentrations in hypercholesterolemic adults with the effect on triglycerides being greater in those with the GA compared with the GG genotype of ESR-ß RsaI.

Daidzein (one of the major isoflavones) can be metabolized to equol in certain individuals. The effects of isoflavones alone and equol status on lipid profiles are still controversial. To evaluate the 6-mo effects of daidzein on cardiovascular risk factors in hypercholesterolemic individuals and the interactions of these effects with equol status and estrogen receptor (ESR) genotypes, we conducted a randomized, double-blind, placebo-controlled trial consisting of 210 hypercholesterolemic adults (40-65 y old). The participants were randomly assigned (177 completed) to consume placebo, 40 mg daidzein (DAI40), or 80 mg daidzein (DAI80) daily for 6 mo. Daidzein decreased serum triglycerides (TGs) by 0.15 ± 0.62 mmol/L (mean ± SD) and 0.24 ± 0.61 mmol/L and decreased serum uric acid by 23 ± 47 µmol/L and 29 ± 44 µmol/L in the DAI40 and DAI80 groups, respectively. These reductions in the DAI40 and DAI80 groups were greater than those in the placebo group (P < 0.05). Other blood lipids, glucose, insulin, or glycated hemoglobin did not significantly change after daidzein treatment. No dose-dependent effects of daidzein were found. The reduction of TGs was influenced by the ESR genotype, with a greater effect observed in participants with the GA genotype compared with those with the GG genotype of ESR-ß RsaI. These effects were not influenced by equol status. Six-month supplementation of daidzein significantly decreased TGs and uric acid. ESR-ß RsaI genotype, not equol status, influenced daidzein's effects on TGs. Daidzein consumption may be effective to improve cardiovascular risk factors, especially in adults with the GA genotype of ESR-ß RsaI. This trial was registered at the Chinese clinical trial registry as ChiCTR-TRC-10001048.

Supplementation of Superfine Powder Prepared from Chaenomeles speciosa Fruit Increases Endurance Capacity in Rats via Antioxidant and Nrf2/ARE Signaling Pathway.

Chaenomeles speciosa fruit is a traditional herb medicine widely used in China. In this study, superfine powder of C. speciosa fruit (SCE), ground by supersonic nitrogen airflow at -140°C, was investigated to assess its in vitro antioxidant activity and in vivo antiphysical fatigue activity. SCE was homogenous (d < 10 µm) and rich in antioxidants like polyphenols, saponins, oleanolic acid, ursolic acid, ascorbic acid, and SOD. According to the in vitro experiments, SCE displayed promising antioxidant activity with powerful FARP, SC-DPPH, and SC-SAR activities. According to the in vivo experiments, rats supplemented with SCE had prolonged exhaustive swimming time (57%) compared to the nonsupplemented rats. Meanwhile, compared to the nonsupplemented rats, the SCE-supplemented rats had higher levels of blood glucose and liver and muscular glycogen and lower levels of LA and BUN. Lower MDA, higher antioxidant enzymes (SOD, CAT, and GSH-Px) activities, and upregulated Nrf2/ARE mediated antioxidant enzymes (HO-1, Trx, GCLM, and GCLC) expression were also detected in the supplemented group. This study indicates that SCE is a potent antioxidant and antifatigue agent, and SCE could be a promising raw material for the food and pharmaceutical industries.

Estrogen receptor and PI3K/Akt signaling pathway involvement in S-(-)equol-induced activation of Nrf2/ARE in endothelial cells.

S-(-)equol, a natural product of the isoflavone daidzein, has been reported to offer cytoprotective effects with respect to the cardiovascular system, but how this occurs is unclear. Interestingly, S-(-)equol is produced by the human gut, suggesting a role in physiological processes. We report that treatment of human umbilical vein endothelial cells and EA.hy926 cells with S-(-)equol induces ARE-luciferase reporter gene activity that is dose and time dependent. S-(-)equol (10-250 nM) increases nuclear factor-erythroid 2-related factor 2 (Nrf2) as well as gene products of Nrf2 target genes heme oxygenase-1 (HO-1) and NAD(P)H (nicotinamide-adenine-dinucleotide-phosphate) quinone oxidoreductase 1 (NQO1). Endothelial cells transfected with an HA-Nrf2 expression plasmid had elevated HA-Nrf2, HO-1, and NQO1 in response to S-(-)equol exposure. S-(-)equol treatment affected Nrf2 mRNA only slightly but significantly increased HO-1 and NQO1 mRNA. The pretreatment of cells with specific ER inhibitors or PI3K/Akt (ICI182,780 and LY294002) increased Nrf2, HO-1, and NQO1 protein, impaired nuclear translocation of HA-Nrf2, and decreased ARE-luciferase activity. Identical experiments were conducted with daidzein, which had effects similar to S-(-)equol. In addition, DPN treatment (an ERß agonist) induced the ARE-luciferase reporter gene, promoting Nrf2 nuclear translocation. Cell pretreatment with an ERß antagonist (PHTPP) impaired S-(-)equol-induced Nrf2 activation. Pre-incubation of cells followed by co-treatment with S-(-)equol significantly improved cell survival in response to H2O2 or tBHP and reduced apoptotic and TUNEL-positively-stained cells. Notably, the ability of S-(-)equol to protect against H2O2-induced cell apoptosis was attenuated in cells transfected with an siRNA against Nrf2. Thus, beneficial effects of S-(-)equol with respect to cytoprotective antioxidant gene activation may represent a novel strategy to prevent and treat cardiovascular diseases.

Effect of green tea on glucose control and insulin sensitivity: a meta-analysis of 17 randomized controlled trials.

BACKGROUND: The results of studies investigating the effect of green tea on glucose control and insulin sensitivity in humans are inconsistent. OBJECTIVE: We aimed to quantitatively evaluate the effect of green tea on glucose control and insulin sensitivity. DESIGN: We performed a strategic literature search of PubMed, EMBASE, and the Cochrane Library (updated to January 2013) for randomized controlled trials that evaluated the effects of green tea and green tea extract on glucose control and insulin sensitivity. Study quality was assessed by using the Jadad scale. Weighted mean differences were calculated for net changes in glycemic measures by using fixed-effects or random-effects models. We conducted prespecified subgroup and sensitivity analyses to explore potential heterogeneity. Meta-regression analyses were conducted to investigate dose effects of green tea on fasting glucose and insulin concentrations. RESULTS: Seventeen trials comprising a total of 1133 subjects were included in the current meta-analysis. Green tea consumption significantly reduced the fasting glucose and hemoglobin A1c (Hb A1c) concentrations by -0.09 mmol/L (95% CI: -0.15, -0.03 mmol/L; P < 0.01) and -0.30% (95% CI: -0.37, -0.22%; P < 0.01), respectively. Further stratified analyses from high Jadad score studies showed that green tea significantly reduced fasting insulin concentrations (-1.16 µIU/mL; 95% CI: -1.91, -0.40 µIU/mL; P = 0.03). CONCLUSIONS: This meta-analysis suggested that green tea had favorable effects, ie, decreased fasting glucose and Hb A1c concentrations. Subgroup analyses showed a significant reduction in fasting insulin concentrations in trials with high Jadad scores.

Effects of soya oligosaccharides and soya oligopeptides on lipid metabolism in hyperlipidaemic rats.

In the present study, we aimed to examine the effects of soya oligosaccharides (SOS) and soya oligopeptides (SOP) on blood lipid levels, release of vasoactive substances, antioxidant activity and faecal bile acid (FBA) excretion in rats fed a high-fat diet (HFD). Male Sprague-Dawley rats were evenly divided into five groups according to diets as follows: regular diet (control), HFD, HFD enriched with 2 % of SOS (SOS), HFD enriched with 3 % of SOP (SOP) and HFD enriched with 2 % SOS and 3 % SOP (SOSP). The results showed that SOS and SOP significantly reduced plasma total cholesterol, LDL-cholesterol and TAG, whereas HDL-cholesterol concentration was significantly increased. Furthermore, SOS and SOP reduced plasma apoB, apoE and the apoB:apoAI ratio, whereas apoAI was significantly increased. Moreover, SOS and SOP also reduced plasma thromboxane A2 (TXA2) and the TXA2:prostacyclin (PGI2) ratio, whereas plasma PGI2 and nitric oxide were significantly increased. In addition, SOS and SOP significantly reduced serum and liver malondialdehyde concentrations and increased FBA excretion. However, we did not observe obvious influences of SOS and SOP on superoxide dismutase activities in the liver of HFD-fed rats. The combination of 2 % SOS and 3 % SOP showed a more marked effect than SOS or SOP alone in improving the lipid profile, release of vasoactive substances and increasing FBA excretion (P < 0.05). In summary, SOS and SOP might help prevent atherosclerosis through improving abnormal blood lipid levels, regulating vasoactive substances and protecting against oxidative stress.

Effects of taurine on glial cells apoptosis and taurine transporter expression in retina under diabetic conditions.

Taurine, a ß-aminosulfonic acid, has been reported to reduce the risk of a number of diseases, including cardiovascular disease, diabetes, and also perhaps to reduce neurodegeneration in the elderly. The transport of taurine is known to be mediated by taurine transporter (TauT). The purpose of this study is to examine the effects of taurine on glial cells apoptosis and on TauT expression in retina of diabetic rats and retinal glial cells cultured with high glucose. TdT-mediated dUTP-biotin nick-end labeling (TUNEL) staining analysis showed that the number of TUNEL-positive cells in taurine treated diabetic rats was significantly lower than those of untreated diabetic rats over the 8-, and 12-week time courses, respectively (all P < 0.001). No TUNEL-positive cells were observed in retina of control groups and taurine treated control groups. In cultured retinal glial cells, the apoptosis in high glucose-treated cells was significantly increased vs the control. When the cells were incubated with high glucose and taurine at 0.1, 1.0 and 10 mmol/l, the percentage of apoptosis was significantly decreased to 16.4, 5.7 and 7.6% respectively (all P < 0.05). With supplementation of taurine in diet and culture medium, higher expression of TauT in retina of diabetic rats and cultured retinal glial cells under diabetic conditions were detected by western-blotting (P < 0.05). Taken together, our data suggest that diabetes or high glucose induced retinal glial cells apoptosis can be inhibited by taurine, and that taurine reverses the diabetes-induced or high glucose-induced decrease in TauT expression.

Dietary taurine supplementation prevents glial alterations in retina of diabetic rats.

The preventive effect of dietary taurine supplementation on glial alterations in retina of streptozotocin-induced diabetic rats was examined in this study. Blood glucose content, content of taurine, glutamate and -amino butyric acid (GABA) and expression of glial fibrillary acid protein (GFAP), vascular endothelial growth factor (VEGF), glutamate transporter (GLAST), glutamine synthetase (GS) and glutamate decarboxylase (GAD) in retina were determined in diabetic rats fed without or with 5% taurine in a controlled trial lasting 12 weeks, with normal rats fed without or with 5% taurine served as controls. Dietary taurine supplementation could not lower glucose concentration in blood (P > 0.05), but caused an elevation of taurine content and a decline in levels of glutamate and GABA in retina of diabetic rats (P < 0.05). The content of GABA in normal control group was not altered by taurine supplementation. With supplementation of taurine in diet, lower expression of GFAP and VEGF while higher expression of GLAST, GS and GAD in retina of diabetic rats were determinated by RT-PCR, Western-blotting and immunofluorescence (P < 0.05). GFAP, VEGF, GLAST, GS and GAD expressions in normal controls were not altered by taurine treatment. This may have prospective implications of using taurine to treat complications in diabetic retinopathy.

Effects of different dietary fatty acids on the fatty acid compositions and the expression of lipid metabolic-related genes in mammary tumor tissues of rats.

In this study, the effects of dietary fatty acids on the fatty acid compositions and lipid metabolic-related genes expression in N-methyl-N-nitrosourea (MNU)-induced rat mammary carcinogenesis were evaluated. The 50-day-old female Sprague-Dawley rats were intervened by different dietary fats (15% wt/wt), including saturated fatty acid (SFA), monounsaturated fatty acid (MUFA), n-6 polyunsaturated fatty acid (PUFA), n-3 PUFA, 1:1 n-6/n-3, 5:1 n-6/n-3, 10:1 n-6/n-3, and 1:2:1 S/M/P (1:1 n-6/n-3), alone or in combination with MNU. There was no mammary tumor occurrence in the control and MNU-treated n-3 PUFA groups after 18 wk. n-3 PUFA diet retarded the weight growth of rats. 1:1 n-6/n-3 diet significantly reduced the MNU-induced tumor incidence and tumor multiplicity compared with SFA, MUFA, n-6 PUFA, 5:1 n-6/n-3, 10:1 n-6/n-3 and 1:2:1 S/M/P diets (42.86% vs. 83.33%-92.31%, 0.79 vs. 2.62-2.85, P < 0.01). Additionally, 1:1 n-6/n-3 diet substantially increased cis-5,8,11,14,17-eicosapentaenoic acid and cis-4,7,10,13,16,19-docosahexaenoic acid levels, whereas it decreased C20:4 level and the mRNA expressions of fatty acid synthase, Cyclooxygenase-2 (COX-2), and 5-lipoxygenase (5-LOX) in mammary tissues (P < 0.05). These results suggest that 1:1 n-6/n-3 in the diet is effective in the prevention of mammary tumor development by increasing the n-3 PUFA content and reducing the expression of lipid metabolic-related genes.

Dietary taurine supplementation ameliorates diabetic retinopathy via anti-excitotoxicity of glutamate in streptozotocin-induced Sprague-Dawley rats.

The purpose of this study was to investigate whether taurine ameliorate the diabetic retinopathy, and to further explore the underlying mechanisms. The Sprague-Dawley rats were injected with streptozotocin to establish experimental diabetic model, then fed without or with 1.2% taurine for additional 4-12 weeks. After that, the protective effects of dietary taurine supplementation on diabetic retinopathy were estimated. Our results showed that chronic taurine supplement effectively improved diabetic retinopathy as changes of histopathology and ultrastructure. The supplementation could not lower plasma glucose concentration (P > 0.05), but caused an elevation in taurine content and a decline in levels of glutamate and gamma-aminobutyric acid (GABA) in diabetic retina (P < 0.05). Moreover, chronic taurine supplementation increased glutamate transporter (GLAST) expression (P < 0.05), decreased intermediate filament glial fibrillary acidic protein (GFAP) and N-methyl-D: -aspartate receptor subunit 1 (NR1) expression in diabetic retina (P < 0.05). These results demonstrated that chronic taurine supplementation ameliorates diabetic retinopathy via anti-excitotoxicity of glutamate in rats.

[Effects of different dietary fatty acid on expression of nuclear receptor genes in breast cancer of rats].

OBJECTIVE: To study the effects of different dietary fatty acid on the expression of nuclear receptor genes in the breast cancer of rats. METHODS: Fifty-day-old female Sprague-Dawley rats were fed on eight different diets containing following fatty acids: saturated fatty acid (SFA); monounsaturated fatty acid (MUFA); n-6 polyunsaturated fatty acid (PUFA); n-3 PUFA; 1:1 n-6/n-3; 5:1 n-6/n-3; 10:1 n-6/n-3; 1:2:1 S/M/P (n-6/n-3 at 1:1). The rats were given a single intraperitoneal injection of methyl-nitrosourea (MNU) at 50 mg/kg body weight to establish the rat model of mammary carcinogenesis, the ultrastructure changes of mammary gland cells in rats were observed by transmission electron microscope, the cell proliferation activity was detected by BrdU-labeled immunocytochemistry, and the expression of PPARbeta and PPARgamma mRNA were assayed by RT-PCR. RESULTS: There was no breast cancer occurring in control groups and the MNU-treated n-3 PUFA group, and the ultrastructure and proliferation activity of mammary gland cells in these groups were normal. In contrast, there appeared obvious marker of adenocarcinomas in mammary gland cells of MNU-induced breast cancer, and a high cell proliferation activity was found in tumor growth-enhancing groups (SFA, MUFA, n-6 PUFA, 5:1 n-6/n-3, 10:1 n-6/n-3 and S/M/P, 21% - 22% of BrdU-labeled cells), while a low cell proliferation activity was detected in rats fed with 1:1 n-6/n-3 diet (13% of BrdU-labeled cells, P < 0.05). Moreover, peroxisome proliferator-activated receptors (PPARs), as important nuclear receptor genes of relating lipid metabolism, the expressions of PPARbeta and PPARgamma mRNA were significantly up-regulated in mammary adipose tissues of MNU-induced breast cancer as compared with the control groups, but the expression levels of peroxisome proliferator-activated receptors (PPARs) in rats fed with 1:1 n-6/n-3 group were lowest (P < 0.05). CONCLUSION: The different dietary fatty acid compositions should diversely adjust the expression of PPARs gene in rats, which maybe have an important role in affecting incidence of breast cancer.