High-fat Treatment Research Articles

Study of active components and mechanisms mediating the hypolipidemic effect of Inonotus obliquus polysaccharides.

Hyperlipidemia is a multifaceted metabolic disease, which is the major risk factor for atherosclerosis and cardiovascular diseases. Traditional Chinese medicine provides valuable therapeutic strategies in the treatment of hyperlipidemia. Inonotus obliquus has been used in traditional medicine to treat numerous diseases for a long time. To screen and isolate the fractions of I. obliquus polysaccharides (IOP) that can reduce blood lipid in the hyperlipemia animals and cell models, and investigate its mechanisms. The active component IOP-A2 was isolated, purified, and identified. Invivo, rats were randomly divided into blank control group (NG), the high-fat treatment group (MG), lovastatin group (PG), and IOP-A group. Compared with MG, the hyperlipidemic rats treated with IOP-A2 had decreased body weight and organ indexes, with the level of serum total cholesterol (TC), triglyceride (TG), and low-density lipoprotein cholesterol (LDL-C) significantly decreased (p < .05), and level of serum high-density lipoprotein cholesterol (HDL-C) significantly increased (p < .05). Hepatocyte steatosis in hepatic lobules was significantly reduced. Invitro, the accumulation of lipid droplets in the model of fatty degeneration of HepG2 cells was significantly alleviated, and cellular TC and TG content was significantly decreased (p < .01). Moreover, the expression of recombinant cytochrome P450 7A1 (CYP7A1) and Liver X Receptor α (LXRα) were up-regulated (p < .05) both invivo and invitro. The results showed that IOP-A2 may exert its hypolipidemic activity by promoting cholesterol metabolism and regulating the expression of the cholesterol metabolism-related proteins CYP7A1, LXRα, SR-B1, and ABCA1.

Betaine for the prevention and treatment of insulin resistance and fatty liver in a high-fat dietary model of insulin resistance in C57BL mice.

The aim was to investigate mechanisms by which betaine improves hepatic insulin signaling in a dietary mouse model of insulin resistance and fatty liver. C57BL 6J mice were fed a standard diet (SF), a standard diet with betaine (SFB), a nutritionally complete high fat (HF) diet, or a high fat diet with betaine (HFB) for 14 weeks. In a separate experiment, mice were fed high fat diet for 18 weeks, half of whom received betaine for the final 4 weeks. Activation of insulin signaling in the liver was assessed by western blot. Insulin signaling was also assessed in insulin resistant primary human hepatocytes treated with betaine. As compared with SF, mice receiving HF diet were heavier, had more hepatic steatosis, and abnormal glucose tolerance test (GTT). Betaine content in liver and serum was 50% lower in HF than in SF; betaine supplementation restored serum and liver betaine content. Betaine treatment of HF reduced whole body insulin resistance as measured by GTT. Betaine treatment of HF increased tyrosine phosphorylation of insulin receptor substrate-1 and phosphorylation (activation) of Akt, and increased hepatic glycogen content. In vitro, betaine reversed insulin resistance in primary human hepatocytes by increasing insulin-stimulated tyrosine phosphorylation of IRS1 and of Akt. Betaine supplementation reduced whole body insulin resistance and increased activation of insulin signaling pathways in the liver in a mouse model of insulin resistance and fatty liver created by feeding a nutritionally complete high fat diet for 14 weeks. Betaine also reduced liver injury as assessed by ALT and by liver histology. In vitro, betaine reversed insulin resistance by increasing insulin-stimulated tyrosine phosphorylation of IRS1 and activation of downstream proteins in the insulin signaling cascade in insulin resistant primary human hepatocytes.

Effects of Dietary Fat Level of Concentrate Mix on Growth Performance, Rumen Characteristics, Digestibility, Blood Metabolites, and Methane Emission in Growing Hanwoo Steers.

This study investigated the effect of different dietary fat levels in concentrate mixes on the growth performance, rumen characteristics, digestibility, blood metabolites, and methane emissions in growing Hanwoo steers. Thirty steers (386 ± 24.6 kg of body weight [BW]; 12 months old), blocked by BW, were randomly assigned to three dietary treatments with varying fat concentrations in concentrate mix (48, 74, and 99 g of ether extract per kg dry matte [DM]). The fat intake of the low-fat treatment represented 4.15% of the total dry matter intake (DMI), while the medium- and high-fat treatments accounted for 5.77% and 7.23% of total DMI, respectively. Concentrate mix DMI decreased with increasing fat level (p < 0.01). The growth rate and digestibility did not significantly differ based on the fat level (p > 0.05). As the fat level increased, propionate in the total ruminal volatile fatty acids increased, and butyrate and acetate-to-propionate decreased (p < 0.01). Cholesterol in blood serum increased significantly with increasing dietary fat levels (p < 0.01). Methane emissions exhibited a linear decrease with increasing fat level (p < 0.05). In conclusion, elevating fat content in the concentrates up to 100 g/kg DM reduced methane emissions without compromising the growth performance of growing Hanwoo steers.

Glycolipotoxicity conferred tendinopathy through ferroptosis dictation of tendon-derived stem cells by YAP activation.

Tendinopathy is a condition characterized by chronic, complex, and multidimensional pathological changes in the tendons. The etiology of tendinopathy is the combination of several factors, and diabetes mellitus (DM) is a risk factor. Increasing evidence has shown that the diabetic microenvironment plays an important role in tendinopathy. However, the mechanism causing tendinopathy in patients with DM remains unclear. Our study found that ferroptosis played an important role in tendinopathy in patients with DM. In vitro, high glucose and high fat treatment was used to simulate the DM microenvironment. Results showed that such a mechanism significantly increased ferroptosis, which was characterized by mass cell death, lipid peroxide accumulation, mitochondrial morphological changes, mitochondrial membrane potential decline, iron overload, and the activation of ferroptosis-related genes, in tendon-derived stem cells cultured in vitro. In the animal studies, db/db mice were used in the DM model, and the db mice had severe tendon injury and high ACSL4 and TfR1 expressions. These phenomena could be alleviated by the ferroptosis inhibitor ferrostatin-1. In conclusion, ferroptosis is associated with tendinopathy in patients with DM, and ferroptosis targeting may be a novel approach for treating diabetic tendinopathy. Our results can provide a new strategy for managing tendinopathy clinically in patients with DM.

PSXVI-6 Ruminal dry Matter Disappearance, Methane Production and Fermentation Parameters as Affected by fat and Protein Concentration in by-Product Supplemented Grass hay-Based Diets

Abstract This batch culture study evaluated the effects of crude protein (CP) and fat concentration on ruminal dry matter disappearance (DMD), methane (CH4) production, and ruminal fermentation in grass hay-based diets supplemented with by-product feeds. Eight treatments provided low or high CP (8 or 12% DM, respectively), with a range of fat concentrations (1.8 to 6.0% DM) and included the following: Control (grass hay only); corn distillers grains with solubles at 8.0% (CDDGS8) and 12% CP (CDDGS12); flax at 8% (FS8) and 12% CP (FS12); canola meal at 8% (Can8); sunflower screenings from Winkler (SFW8) or Deloraine (SFD8) at 8%. Data were analyzed as a randomized complete block design, with fixed effect of treatment and random effects of block and treatment × block. Comparisons were performed between a) Control and mean of by-product treatments b) low and high CP treatments c) CDDGS treatments, d) FS treatments and e) SF treatments. Comparisons between low and high fat treatments at both CP concentrations, as well as CDDGS and FS treatments differing in fat concentrations were also conducted. Overall, DMD did not differ between the Control and by-product treatments; however, comparisons indicated decreased (P &amp;lt; 0.001) DMD in treatments with 8% compared with 12% CP. The DMD was also greater (P≤0.009) with low fat compared with high fat, regardless of CP. Methane production did not differ between any of the low and high CP treatments but was greater (P≤0.003) in the low fat compared with high fat treatments, regardless of CP, as well as in FS vs CDDGS and SFD vs SFW. No effects of treatment on fermentation parameters were observed. In conclusion, greater CP increased DMD in vitro but did not affect CH4 or fermentation. Additionally, greater dietary fat can mitigate enteric CH4 production, but can negatively impact DMD in grass hay-based diets.

Treatment of high fat diet-induced obese pregnant mice with IL-6 receptor antibody does not ameliorate placental function and fetal growth restriction.

Pregnancy complications and adverse birth outcomes are in part fueled by the rise in obesity and its associated co-morbidities in western societies. Fetal healthy development and placental function are disturbed by an obese, inflammatory environment associated with cytokines, such as interleukin-6, causing inadequate supply of nutrients to the fetus and perinatal programming with severe health consequences. Mice received high fat diet (HFD) before and during gestation to induce obesity. We performed an IL-6 receptor antibody (MR16-1) treatment in pregnant obese mice at embryonic days E0.5, E7.5 and E14.5 to investigate whether this could ameliorate HFD-induced and obesity-associated placental dysfunction, evaluated by stereology and western blot, and improve offspring outcome at E15.5 in obese dams. We observed fewer fetuses below the 10th percentile and placental vascularization was less aggravated following MR16-1 treatment of obese dams, showing slight improvements in labyrinth zone (Lz) vascularization. However, placental dysfunction and fetal growth restriction were still apparent in MR16-1 dams compared to lean control dams. Molecular analysis showed significantly elevated IL-6 level in placentas of MR16-1 treated dams. Treatment with MR16-1 blocks IL-6 signaling in the placenta, but has only limited effects on preventing HFD-associated placental dysfunction and offspring outcomes in mice, suggesting further mechanisms in the deterioration of placental vascularization and fetal nutrient supply as a consequence of maternal obesity.

Impairment of endometrial decidual reaction in early pregnant mice fed with high fat diet.

To investigate the effect of obesity induced by high fat diet on decidual reaction of endometrium in mice, and the effect of high fat treatment on decidual reaction of endometrial stromal cells. Twelve 4-week-old healthy C57BL/6J female mice were randomly divided into high fat diet group and control group with 6 mice in each group. They were fed with high fat diet (22 kJ/g) or normal diet (16 kJ/g) for 12 weeks, respectively. The body weight of mice was measured every week. After feeding for 12 weeks, the body length and width of mice were measured, and the levels of fasting serum triglyceride and total cholesterol were determined. Then the mice were mated with healthy C57BL/6J male mice, and the uterine tissues were collected on the seventh day of pregnancy. The decidual cells and collagen fibers in mouse endometrium was observed by HE staining and Masson staining respectively. The expression of decidual reaction related proteins in mouse endometrium were detected by immunohistochemistry and Western blotting. Mouse endometrial stromal cells (mESCs) were isolated and treated with the oleic acid and palmitic acid in vitro, and the decidual reaction was induced with estradiol and progesterone. The accumulation of lipid droplets in mESCs was observed by oil red O and Bodipy staining. The cytoskeleton of mESCs was observed by phalloidin staining. The levels of decidual reaction related genes and proteins were detected by real-time fluorescence quantitative PCR and Western blotting. After feeding for 12 weeks, the body weight of mice in the high fat group was significantly higher than that in the control group ( P<0.01), and there was no significant difference in body length between two groups ( P>0.05), but the body width of mice in the high fat group was significantly larger than that in the control group ( P<0.01), and the levels of serum triglyceride and total cholesterol were significantly higher than those in the control group (Both P<0.05). The number of embryo implantation in the high fat group was significantly less than that in the control group ( P<0.01). The differentiation of mESCs to decidual cells in high fat group was slow and abnormal. The expression levels of decidual reaction markers bone morphogenetic protein (BMP)2 and homeobox A10 (HOXA10) were lower than those in the control group, and there was significant difference in the expression level of HOXA10 ( P<0.01). The results of oil red O and Bodipy staining in mESCs showed that after high fat treatment, the accumulation of lipid droplets increased significantly, phalloidin staining showed abnormal cytoskeleton morphology. The expression levels of decidual reaction related genes dtprp, HOXA10 and proteins BMP2, HOXA10 and cyclooxygenase (COX)2 were significantly lower than those in the control group ( P<0.05). Obesity induced by high fat diet and high fat treatment can impair the decidual reaction of endometrium and endometrial stromal cells in mice.

High-sugar high-fat treatment induces autophagy of retinal microvascular endothelial cells

ObjectiveTo investigate the role of high-sugar high-fat treatment in inducing autophagy of rat retinal microvascular endothelial cells. MethodsThe optimal concentrations and time points of glucose and oxidized low-density lipoprotein (ox-LDL) in inducing rat retinal microvascular endothelial cells were determined by examining the proliferate rate by CCK-8 assay. They were divided into control group (blank control), model group (treatment of 50 mM glucose and 10 μg/ml ox-LDL for 24 h), chloroquine group (treatment of 20 μM chloroquine, 50 mM glucose and 10 μg/ml ox-LDL for 24 h), resveratrol group (treatment of 50 μM resveratrol, 50 mM glucose and 10 μg/ml ox-LDL for 24 h) and MITO-Tempol group (treatment of 20 μM MITO-Tempol, 50 mM glucose and 10 μg/ml ox-LDL for 24 h). Reactive oxygen species (ROS) level in rat retinal microvascular endothelial cells induced with high sugar high-fat treatment was measured by flow cytometry. In addition, protein levels of cathepsin B and cathepsin D in rat retinal microvascular endothelial cells induced with high sugar high-fat treatment were examined by immunofluorescence, and protein levels of LC3 A/B and the autophagy substrate P62 were detected by Western blot. ResultsPrimary retinal microvascular endothelial cells were isolated from neonatal Sprague-Dawley (SD) rats. ROS level was significantly higher in model group than that of control group (P < 0.05). Compared with that of model group, ROS level was significantly reduced in chloroquine group and MITO-Tempol group, which was significantly elevated in resveratrol group (P < 0.05). Positive expressions of cathepsin B and cathepsin D were significantly reduced in model group than those of control group (P < 0.05). They were significantly elevated in chloroquine group and MITO-Tempol group, and reduced in resveratrol group than those of model group (P < 0.05). LC3 A/B and P62 were significantly upregulated in model group than those of control group (P < 0.05). Compared with those of model group, LC3 A/B and P62 were significantly downregulated in chloroquine group and MITO-Tempol group, and upregulated in resveratrol group (P < 0.05). ConclusionHigh-sugar high-fat treatment induces autophagy of rat retinal microvascular endothelial cells, which can be intervened to a certain extent by chloroquine and MITO-Tempol.

Ruminal dry matter disappearance, total gas and methane production, and fermentation parameters as affected by fat and protein concentration in by-product supplemented grass hay-based diets

Context Dietary manipulation is an important means to mitigate methane emissions; however, relatively few options exist for forage-based diets. Aims This batch culture study evaluated the effects of crude protein (CP) and fat concentration on ruminal DM disappearance (DMD), total gas (GP) and methane production, and ruminal fermentation in grass hay-based diets supplemented with a range of by-product feeds. Methods Eight treatments provided low or high CP (8 or 12% diet DM, respectively), with range of fat concentrations (1.8–6.0% diet DM), and included: control (grass hay only); corn distillers grains with solubles at 8% (CDDGS8) and 12% CP (CDDGS12); flax at 8% (FS8) and 12% CP (FSCDDGS12); canola meal at 8% (Can8); and sunflower screenings from Winkler (SFW8) or Deloraine (SFD8) at 8%. Data were analysed as a randomised complete block design, with fixed effect of treatment and random effects of block and treatment × block. Comparisons were performed between: (1) control and mean of by-product treatments, (2) low and high CP treatments, (3) CDDGS treatments, (4) FS treatments, and (5) SF treatments. Low- and high-fat treatments at both CP concentrations, and the means of CDDGS and FS treatments differing in fat concentrations were also compared. Key results The DMD did not differ between control and by-product treatments; however, DMD was lower (P &lt; 0.001) in treatments with 8% compared with 12% CP, and was higher (P ≤ 0.009) with low fat compared with high fat, regardless of CP. Total GP was not affected by CP; however, at low CP, treatments with higher fat had lower GP (P ≤ 0.015). Methane production did not differ between any of the low and high CP treatments, but was higher (P ≤ 0.003) in the low-fat compared with high-fat treatments, regardless of CP, as well as in FS versus CDDGS and SFD versus SFW. Conclusions Higher CP increased DMD in vitro, but did not affect GP, methane or fermentation. Implications Higher dietary fat can mitigate enteric methane production, but can negatively impact DMD in grass hay-based diets, which is an important consideration in terms of animal performance.

High-fat diet impairs ferroptosis and promotes cancer invasiveness via downregulating tumor suppressor ACSL4 in lung adenocarcinoma

BackgroundLong-chain acyl-CoA synthetase-4 (ACSL4) is involved in fatty acid metabolism, and aberrant ACSL4 expression could be either tumorigenic or tumor-suppressive in different tumor types. However, the function and clinical significance of ACSL4 in lung adenocarcinoma remain elusive.ResultsACSL4 was frequently downregulated in lung adenocarcinoma when analyzing both the TCGA database and the validation samples, and the lower ACSL4 expression was correlated with a worse prognosis. Using gene set enrichment analysis, we found that high ACSL4 expression was frequently associated with the oxidative stress pathway, especially ferroptosis-related proteins. In vitro functional studies showed that knockdown of ACSL4 increased tumor survival/invasiveness and inhibited ferroptosis, while ACSL4 overexpression exhibited the opposite effects. Moreover, high-fat treatment could also inhibit erastin-induced ferroptosis by affecting ACSL4 expression. The anti-tumor effects of ferroptosis inducers and the anti-ferroptosis effects of the high-fat diet were further validated using the mouse xenograft model.ConclusionsACSL4 plays a tumor-suppressive role in lung adenocarcinoma by suppressing tumor survival/invasiveness and promoting ferroptosis. Our study provided a theoretical reference for the application of ferroptotic inducers and dietary guidance for lung adenocarcinoma patients.

Obesity regulates miR-467/HoxA10 axis on osteogenic differentiation and fracture healing by BMSC-derived exosome LncRNA H19.

This study explored the therapeutic effect of bone marrow mesenchymal stem cell‐derived exosomes on the treatment of obesity‐induced fracture healing. Quantitative real‐time PCR was used to detect the expression of lncRNA H19, miR‐467 and Hoxa10 and combined with WB detection to detect osteogenic markers (RUNX2, OPN, OCN). Determine whether exosomes have entered BMSCs by immunofluorescence staining. Alkaline phosphatase (ALP) and alizarin red staining (ARS) staining were used to detect ALP activity and calcium deposition. We found that high‐fat treatment can inhibit the secretion of BMSCs‐derived exosomes and affect the expression of H19 carried by them. In vivo and in vitro experiments show that high‐fat or obesity factors can inhibit the expression of osteogenic markers and reduce the staining activity of ALP and ARS. The treatment of exosomes from normal sources can reverse the phenomenon of osteogenic differentiation and abnormal fracture healing. Further bioinformatics analysis found that miR‐467 as a regulatory molecule of lncRNA H19 and Hoxa10, and we verified the targeting relationship of the three through dual luciferase report experiments. Further, we found similar phenomena in ALP and ARS staining. Bone marrow mesenchymal stem cell‐derived exosomes improve fracture healing caused by obesity.

Cafeteria Diet and High-Fructose Rodent Models of NAFLD Differ in the Metabolism of Important PUFA and Palmitoleic Acid without Additional Influence of Sex.

The objective of this study was to evaluate the influence of high-fat (HF) and cafeteria diet (CAF) diets and sex on the metabolism of important fatty acids in the liver and perirenal fat tissue. Dietary treatments induced changes in the fatty acid profile in comparison to the untreated group, but the characteristic differences between treated groups were also observable. The HF diet induced an increase in the content of C16:1n-7 and C18:1n-7 in the liver phospholipids (PL) and triglycerides (TG) and perirenal fat tissue compared to the control and CAF diet. The CAF diet induced a more drastic decrease in both n-3 and n-6 polyunsaturated fatty acids (PUFA), including depletion of eicosapentaenoic acid (EPA). The CAF diet also increased the content of n-6 docosapentaenoic acid (DPAn-6) in the liver and decreased it in the perirenal fat. Sex also had a significant influence on the fatty acid profile, but the variables with the highest differences between the CAF and HF treatments were identical in the male and female rats. In this study, we have established that two dietary models of non-alcoholic fatty liver disease (NAFLD) led to characteristic changes in the hepatic and perirenal fat fatty acid profile, in contrast to the control diet and in comparison with each other. These differences could play an important role in the interpretation of the experimental results of nutritional studies.

Effects of different ratios of n-6/n-3 polyunsaturated fatty acid on adiponectin, glycolipid metabolism and antioxidant capacity in high fat-diet fed rats

To investigate effects of different ratios of n-6/n-3 Polyunsaturated fatty acid(PUFA) on adiponectin, glycolipid metabolism and antioxidant capacity in high fat-diet fed rats. Fixty male Wistar rats were randomly divided into control group(CON, 17% energy from fat, n-6/n-3 PUFA=5∶1) and high-fat treatment groups(1∶1 group∶n-6/n-3 PUFA=1∶1, 5∶1 group, n-6/n-3 PUFA=5∶1, 10∶1 group∶ n-6/n-3 PUFA=10∶1 and 20∶1 group∶ n-6/n-3 PUFA=20∶1, 42% energy from fat). Rats were fed for 12 week. Serum glucose and lipid(0, 4, 8 and 12 week) were detected. Antioxidant indexes(0 and 12 week), adiponectin mRNA and protein expressions in epididymal adipose tissues as well as serum adiponectin(12 week) were measured. Baseline data showed no significant inter-group difference(P&gt;0. 05). 1∶1 and 5∶1 showed no significant changes in serum glucose compared with control at all time points(P&gt;0. 05), while 10∶1 and 20∶1 significantly increased it at the 12 th week(P&lt;0. 05). At the 12 th week, total cholesterol(TC) and triglycerides(TG) in high-fat treatment groups were significantly higher than control(P&lt;0. 01), with 20∶1 showing significant increment of TG compared with other high-fat treatment groups(P&lt;0. 01). At the 12~(th) week, glutathione peroxidase and superoxide dismutase content in high-fat treatment groups all decreased significantly compared with control(P&lt;0. 05), and 20∶1 decreased most. Malondialdehyde content significantly increased in high-fat treatment groups(P&lt;0. 05), and 10∶1 increased most. Adiponectin mRNA expression significantly decreased in 20∶1 compared with control, 1∶1 and 5∶1(P&lt;0. 05). Increment of adiponectin protein expression was significantly shown in 5∶1 compared with other high-fat treatment groups(P&lt;0. 05), while it was most obviously decreased in 20∶1(P&lt;0. 05). Lower n-6/n-3 PUFA ratios(1∶1 and 5∶1) contributed to improvement of glycolipid metabolism and antioxidant capacity as well as increment of adiponectin expression of rats fed with high-fat diet.

Vanadium in high-fat diets sourced from egg yolk decreases growth and antioxidative status of Wistar rats.

The objective of this paper was to evaluate the effect of vanadium (V) in high-fat diets sourced from egg yolk on body weight gain, feed intake, blood characteristics and antioxidative status of Wistar rats. A total of 72 female Wistar rats were allocated according to a 2 × 4 factorial design throughout a 5-wk trial, including 2 levels of dietary fat (normal and high; ether extract 40.3 and 301.2 g/kg; fat sourced from egg yolk) and 4 levels of dietary V (0, 3, 15 and 30 mg/kg). Vanadium decreased (P ≤ 0.05) body weight gain (V at 30mg/kg during wk 1 and 2; V at 15 and 30 mg/kg during the overall phase), feed intake (V at 30 mg/kg during wk 3 and the overall phase; V at 15 and 30 mg/kg during wk 4), but increased the relative weight of liver (V at 30 mg/kg, P ≤ 0.05). Moreover, increasing dietary V significantly increased (P ≤ 0.05) plasma aspartate aminotransferase, alanine aminotransferase and malondialdehyde levels and decreased triglyceride level, and V at 30 mg/kg in high-fat treatment had the highest or lowest values (interaction, P ≤ 0.05). Under the same dietary V dose, V residual content in liver (dietary V at 15 and 30 mg/kg) and kidney (dietary V at 15 mg/kg) was higher in high-fat diet treatment compared with normal-fat diet treatment (P ≤ 0.05). In conclusion, it is suggested that V could decrease the body weight together with the feed intake, and the high fat could enhance oxidative stress induced by V of Wistar rats.

Treatment of High Fat Diet-Induced Hyperhomocysteinemia with Pyridoxine, Cinnamon and Pitavastatin in Young Male Albino Rats

.

2167-P: Gamma-Hydroxybutyrate Prevents Lipotoxicity-Induced ß-Cell Dysfunction

Prolonged exposure to high levels of fatty acids impairs the insulin secretory capacity of pancreatic β-cells through mechanisms involving oxidative stress (lipotoxicity). Beta-cell lipotoxicity is thought to play an important role in the β-cell failure of type 2 diabetes. Antioxidants can protect β-cells from lipotoxicity by decreasing oxidative stress. Gammahydroxybutyrate (GHB), an endogenous neurotransmitter currently safely used as a treatment for narcolepsy, is also found in cells as an energy source and antioxidant. Previous studies have shown that GHB can protect mice from streptozotocin and alloxan induced diabetes; both compounds are generators of oxidative stress and yield models of type 1 diabetes. However, the effect of GHB in models of type 2 diabetes has not been investigated. We hypothesized that GHB can protect β-cells from lipotoxicity. We first investigated the effectiveness of GHB in preventing β-cell dysfunction in high-fat treatment (palmitate) in an in vitro model with freshly isolated mouse islets. Beta-cell function was determined by glucose stimulated insulin secretion assays. Islets incubated with GHB were protected from β-cell lipotoxicity that resulted from the concurrent 48h exposure to palmitate. The antioxidant effects of GHB in lipotoxicity were further investigated by measuring reactive oxygen species (ROS) levels. GHB prevented the increase in ROS that was observed with the palmitate treatment while GHB by itself had no effects. While further studies need to be done to elucidate possible mechanisms of action of GHB beyond its antioxidant effect as well as GHB effectiveness in vivo, our findings suggest that GHB or potentially GHB derivatives may be of interest for their β-cell protective properties. Disclosure L. Yeung: None. A. Ivovic: None. Y. Tan: None. B. Batchuluun: None. M. Mamelak: None. A. Giacca: Research Support; Self; Jazz Pharmaceuticals. Funding Jazz Pharmaceuticals plc

Myeloid differentiation protein 1 protected myocardial function against high-fat stimulation induced pathological remodelling.

Myeloid differentiation 1 (MD‐1) is a secreted protein that regulates the immune response of B cell through interacting with radioprotective 105 (RP105). Disrupted immune response may contribute to the development of cardiac diseases, while the roles of MD‐1 remain elusive. Our studies aimed to explore the functions and molecular mechanisms of MD‐1 in obesity‐induced cardiomyopathy. H9C2 myocardial cells were treated with free fatty acid (FFA) containing palmitic acid and oleic acid to challenge high‐fat stimulation and adenoviruses harbouring human MD‐1 coding sequences or shRNA for MD‐1 overexpression or knockdown in vitro. MD‐1 overexpression or knockdown transgenic mice were generated to assess the effects of MD‐1 on high‐fat diet (HD) induced cardiomyopathy in vivo. Our results showed that MD‐1 was down‐regulated in H9C2 cells exposed to FFA stimulation for 48 hours and in obesity mice induced by HD for 20 weeks. Both in vivo and in vitro, silencing of MD‐1 accelerated myocardial function injury induced by HD stimulation through increased cardiac hypertrophy and fibrosis, while overexpression of MD‐1 alleviated the effects of HD by inhibiting the process of cardiac remodelling. Moreover, the MAPK and NF‐κB pathways were overactivated in MD‐1 deficient mice and H9C2 cells after high‐fat treatment. Inhibition of MAPK and NF‐κB pathways played a cardioprotective role against the adverse effects of MD‐1 silencing on high‐fat stimulation induced pathological remodelling. In conclusion, MD‐1 protected myocardial function against high‐fat stimulation induced cardiac pathological remodelling through negative regulation for MAPK/NF‐κB signalling pathways, providing feasible strategies for obesity cardiomyopathy.

Obesity programmed by prenatal dexamethasone and postnatal high-fat diet leads to distinct alterations in nutrition sensory signals and circadian-clock genes in visceral adipose tissue

BackgroundPrenatal dexamethasone treatment has been shown to enhance the susceptibility of offspring to postnatal high-fat (HF) diet-induced programmed obesity. We investigated the metabolic phenotypes, nutrient-sensing signal and circadian-clock genes in adipose tissue that are programmed by prenatal dexamethasone exposure and postnatal HF diet.MethodsMale offspring of Sprague-Dawley rats were divided into four experimental groups: normal diet, prenatal dexamethasone exposure, postnatal HF diet, and prenatal dexamethasone plus postnatal HF diet. Postnatal HF diet was prescribed from weaning to 6 months of age.ResultsPrenatal dexamethasone and postnatal HF diet exerted synergistic effects on body weight and visceral adiposity, whereas prenatal dexamethasone and postnatal HF diet altered the metabolic profile and caused leptin dysregulation. Prenatal dexamethasone and postnatal HF diet distinctly influenced nutrient-sensing molecules and circadian-clock genes in adipose tissue. The mRNA expression of mTOR, AMPK-α2, PPAR-α, and PPAR-γ was suppressed by prenatal dexamethasone but enhanced by postnatal HF diet.ConclusionPrenatal dexamethasone and postnatal HF treatment cause dysregulation of nutrient-sensing molecules and circadian-clock genes in visceral adipose tissue. Characterizing altered nutrient-sensing molecules and circadian-clock genes has potential therapeutic relevance with respect to the pathogenesis and treatment of prenatal stress and postnatal HF diet-related metabolic disorders.

The Maternal Impact of AdGHRKO Mice on Glucose Metabolism

Genetically modified mouse models provide effective tools to explore the occurrence development and therapy of various diseases, especially the metabolic diseases such as diabetes. In line with the reported maternal inheritance of glucose homeostasis via maternally expressed gene activity, we found that a tissue-specific knockout exhibited maternal influence on insulin sensitivity, resulting in a lower liability for diabetes in the offsprings. Using the Cre/LoxP system, we constructed a mouse model of adipose tissue-specific growth hormone receptor (GHR) knockout (AdGHRKO). Unlike other tissue-specific GHR knockouts, AdGHRKO was found to be maternally inheritable. Compared with female AdGHRKO mice born from Flox mothers, female KO mice born from KO mothers displayed resistance to diet-induced obesity from a high-fat diet for 8 weeks. and the difference in body weight was exclusively due to a significant reduction in white fat tissue, especially from decreased subcutaneous deposition. Moreover, KO mice from KO mothers had better insulin sensitivity and glucose tolerance after high-fat treatment for 8 weeks. Our data suggests that the phenotype of metabolic stability in progeny is strongly affected by the maternal genotype. To support this, we also found that Flox mice born from KO mothers presented similar phenotypic traits (improved glucose tolerance and insulin resistance) of protection from high fat induced diabetes, which was comparable to the KO mice born from KO mothers. Our ongoing studies are to determine if this phenomenon is caused by alterations in maternal hormone levels or some unknown mitochondrial activities. Nonetheless, how adipose tissue specific ablation of GHR exerts its effects on metabolic syndromes through maternal cues is of high interest not only to pure genetic studies but also to medical practice. Disclosure X. Wang: None. A. Mi: None. Y. Liu: None. D. Wang: None. L. Ran: None. Y. Wu: None.

Overexpression of hexokinase 2 reduces mitochondrial calcium overload in coronary endothelial cells of type 2 diabetic mice.

Coronary microvascular rarefaction, due to endothelial cell (EC) dysfunction, is one of the causes of increased morbidity and mortality in diabetes. Coronary ECs in diabetes are more apoptotic due partly to mitochondrial calcium overload. This study was designed to investigate the role of hexokinase 2 (HK2, an endogenous inhibitor of voltage-dependent anion channel) in coronary endothelial dysfunction in type 2 diabetes. We used mouse coronary ECs (MCECs) isolated from type 2 diabetic mice and human coronary ECs (HCECs) from type 2 diabetic patients to examine protein levels and mitochondrial function. ECs were more apoptotic and capillary density was lower in the left ventricle of diabetic mice than the control. MCECs from diabetic mice exhibited significant increase in mitochondrial Ca2+ concentration ([Ca2+]mito) compared with the control. Among several regulatory proteins for [Ca2+]mito, hexokinase 1 (HK1) and HK2 were significantly lower in MCECs from diabetic mice than control MCECs. We also found that the level of HK2 ubiquitination was higher in MCECs from diabetic mice than in control MCECs. In line with the data from MCECs, HCECs from diabetic patients showed lower HK2 protein levels than HCECs from nondiabetic patients. High-glucose treatment, but not high-fat treatment, significantly decreased HK2 protein levels in MCECs. HK2 overexpression in MCECs of diabetic mice not only lowered the level of [Ca2+]mito, but also reduced mitochondrial reactive oxygen species production toward the level seen in control MCECs. These data suggest that HK2 is a potential therapeutic target for coronary microvascular disease in diabetes by restoring mitochondrial function in coronary ECs.