Increased Serum Free Fatty Acids Research Articles

Hepatic Activin E mediates liver-adipose inter-organ communication, suppressing adipose lipolysis in response to elevated serum fatty acids

ObjectiveThe liver is a central regulator of energy metabolism exerting its influence both through intrinsic processing of substrates such as glucose and fatty acid as well as by secreting endocrine factors, known as hepatokines, which influence metabolism in peripheral tissues. Human genome wide association studies indicate that a predicted loss-of-function variant in the Inhibin βE gene (INHBE), encoding the putative hepatokine Activin E, is associated with reduced abdominal fat mass and cardiometabolic disease risk. However, the regulation of hepatic Activin E and the influence of Activin E on adiposity and metabolic disease are not well understood. Here, we examine the relationship between hepatic Activin E and adipose metabolism, testing the hypothesis that Activin E functions as part of a liver-adipose, inter-organ feedback loop to suppress adipose tissue lipolysis in response to elevated serum fatty acids and hepatic fatty acid exposure. MethodsThe relationship between hepatic Activin E and non-esterified fatty acids (NEFA) released from adipose lipolysis was assessed in vivo using fasted CL 316,243 treated mice and in vitro using Huh7 hepatocytes treated with fatty acids. The influence of Activin E on adipose lipolysis was examined using a combination of Inhbe knockout mice, a mouse model of hepatocyte-specific overexpression of Activin E, and mouse brown adipocytes treated with Activin E enriched media. ResultsIncreasing hepatocyte NEFA exposure in vivo by inducing adipose lipolysis through fasting or CL 316,243 treatment increased hepatic Inhbe expression. Similarly, incubation of Huh7 human hepatocytes with fatty acids increased expression of INHBE. Genetic ablation of Inhbe in mice increased fasting circulating NEFA and hepatic triglyceride accumulation. Treatment of mouse brown adipocytes with Activin E conditioned media and overexpression of Activin E in mice suppressed adipose lipolysis and reduced serum FFA levels, respectively. The suppressive effects of Activin E on lipolysis were lost in CRISPR-mediated ALK7 deficient cells and ALK7 kinase deficient mice. Disruption of the Activin E-ALK7 signaling axis in Inhbe KO mice reduced adiposity upon HFD feeding, but caused hepatic steatosis and insulin resistance. ConclusionsTaken together, our data suggest that Activin E functions as part of a liver-adipose feedback loop, such that in response to increased serum free fatty acids and elevated hepatic triglyceride, Activin E is released from hepatocytes and signals in adipose through ALK7 to suppress lipolysis, thereby reducing free fatty acid efflux to the liver and preventing excessive hepatic lipid accumulation. We find that disrupting this Activin E-ALK7 inter-organ communication network by ablation of Inhbe in mice increases lipolysis and reduces adiposity, but results in elevated hepatic triglyceride and impaired insulin sensitivity. These results highlight the liver-adipose, Activin E-ALK7 signaling axis as a critical regulator of metabolic homeostasis.

Acute exercise modulates the inflammatory response in adipose tissue in both lean and obese mice

ObjectivesAcute physical exercise acts as a metabolic stressor, promoting activation of the immune system, and this response could be relevant in the adipose tissue remodeling process. In addition, some cytokines have important functions in lipolysis. Because chronic exercise improves obesity-related metabolic and inflammatory dysfunction, herein we investigated the effect of acute exercise on the inflammatory responses in the adipose tissues of lean and obese mice. MethodsLean mice were fed a standard chow diet, whereas obese mice were fed a high-refined carbohydrate diet for 8 wk. Both groups were subjected to 60 min of moderate-intensity exercise. ResultsIn the epididymal adipose tissue of lean mice, exercise enhanced interleukin (IL)-6 and tumor necrosis factor-α levels, which correlated positively with increased serum free fatty acid concentrations. In vivo confocal imaging of epididymal adipose tissue vessels revealed higher recruitment of neutrophils after exercise. Also, the number of leukocytes expressing CD11b+F480– was elevated 6 h after exercise. Similarly, the chemokine (C-X-C motif) ligand 1 level increased at 6 h and remained high until 24 h after exercise. Myeloperoxidase activity was increased at 6, 12, and 24 h after exercise. Surprisingly, however, no changes were observed in epididymal adipose tissue from obese mice, considering proinflammatory cytokines (IL-6 and tumor necrosis factor-α). On the other hand, IL-13, IL-4, and IL-10 levels were higher in obese mice after exercise. ConclusionsThese data suggest that acute exercise promotes an inflammatory response in the adipose tissue of lean mice that is observed as part of its role in adipose tissue remodeling. In contrast, acute exercise promotes an antiinflammatory response in adipose tissue from obese mice, likely as an important tool for restoring homeostasis.

Effect of Cold Exposure and Exercise on Insulin Sensitivity and Serum Free Fatty Acids in Obese Rats.

This study aimed to explore the effect of exercise and cold exposure on insulin sensitivity and the level of serum free fatty acids (FFA) in diet-induced obese rats. Sixty-four diet-induced obese rats were randomly assigned to eight groups: room temperature-sedentary, room temperature-exercise, acute cold exposure-sedentary, acute cold exposure-exercise, intermittent cold exposure-sedentary, intermittent cold exposure-exercise, sustained cold exposure-sedentary, and sustained cold exposure-exercise. After the interventions, the homeostatic model assessment for insulin resistance (HOMA-IR) values, the level of serum FFA, subcutaneous fat ratio (SFR) and visceral fat ratio, enzyme activities of adipose triglyceride lipase, and lipoprotein lipase (LPL) in inguinal adipose tissue, and protein expression of PGC1-α and p38 MAPK in skeletal muscle were investigated. We found that exercise ( P = 0.0136) and cold exposure ( P < 0.0001) reduced HOMA-IR values independently. Exercise reduced serum FFA ( P = 0.0041), whereas cold exposure did not affect them. Moreover, the HOMA-IR values were positively correlated with the serum FFA levels ( r = 0.32, P = 0.01). SFR or visceral fat ratio was coordinately reduced by the interaction (for SFR, P = 0.0015) or opposing main effects between or of cold exposure and exercise, supporting the reduction of serum FFA. However, cold exposure or exercise increased the activity of adipose triglyceride lipase and LPL independently or interactively (for LPL, P = 0.0143), suggesting an increase in serum FFA. Finally, cold exposure and exercise enhanced protein expression of PGC1-α and p38 MAPK independently or interactively (for p38 MAPK, P = 0.0226), suggesting increased uptake and oxidation of serum FFA in muscle. These results suggest that the combination of exercise and cold exposure may result in more serum FFA utilization than production and thus lead to reduced serum FFA and increased insulin sensitivity.

LBSUN85 Acipimox Normalizes The Cardiac Phenotype Induced By Electronic Cigarettes

Abstract Electronic nicotine delivery systems or electronic cigarettes (e-cigarettes) are becoming exceptionally popular in the world as an alternative to conventional nicotine cigarettes, both among smokers and people who have never smoked. Nicotine can induce lipolysis in adipose tissue, leading to increased serum free fatty acids (FFAs). Increased levels of FFAs are one of the key elements in generating a pro-inflammatory response and lead to ectopic lipid accumulation, lipotoxicity, mitochondrial dysfunction, and DNA damage. Our laboratory has shown that e-cigarettes induce cardiac dysfunction associated with oxidative stress and inflammatory phenotype. We investigated the effects of acipimox, an antihyperlipidemic drug that blocks lipolysis, on e-cigarettes-induced cardiac dysfunction and its associated inflammatory signals and oxidative stress. C57BL/6J wild type mice on high fat diet were exposed to saline, e-cigarette with nicotine (2.4%), e-cigarette (2.4%) plus acipimox for 12 weeks. Fractional shortening and ejection fraction was decreased in mice exposed to e-cigarette (2.4%) compared with saline and acipimox. Therefore, acipimox normalized the e-cigarette-induced cardiac dysfunction. Transcriptomic evaluation with Gene Set Enrichment Analysis revealed that e-cigarette treated mice had genes enriched in the G2/M DNA damage checkpoint pathways. These transcriptomic changes were normalized by acipimox. Mice exposed to e-cigarettes had increased circulating levels of M-CSF, IL-6, and FFAs, which were decreased by acipimox. Mice exposed to e-cigarette (2.4%) had increased cardiac Heme oxygenase 1, a marker of oxidative stress. Additionally, treatment with e-cigarette (2.4%) increased the apurinic/apyrimidinic sites. This marker of oxidative DNA damage was normalized by acipimox. Understanding the consequences of e-cigarette use on the cardiovascular system is directly relevant to developing policies related to e-cigarette use. Presentation: Sunday, June 12, 2022 12:30 p.m. - 2:30 p.m.

Fatty acids of type 2 diabetic serum decrease the stemness properties of human adipose-derived mesenchymal stem cells.

In type 2 diabetes, dyslipidemia and increased serum free fatty acids (FFAs) exacerbate the development of the disease through a negative effect on insulin secretion. Adipose-derived mesenchymal stem cells (AdMSCs) play a key role in regenerative medicine, and these cells can potentially be applied as novel therapeutic resources in the treatment of diabetes. In this study, AdMSCs were treated with diabetic or nondiabetic serum FFAs isolated from women of menopausal age. Serum FFAs were analyzed using gas-liquid chromatography. The expression level of the stemness markers CD49e and CD90 and the Wnt signaling target genes Axin-2 and c-Myc were evaluated using real-time PCR. The proliferation rate and colony formation were also assessed using a BrdU assay and crystal violet staining, respectively. The level of glutathione was assessed using cell fluorescence staining. Compared to nondiabetic serum, diabetic serum contained a higher percentage of oleate (1.5-fold, p < 0.01). In comparison with nondiabetic FFAs, diabetic FFAs demonstrated decreasing effects on the expression of CD90 (-51%, p < 0.001) and c-Myc (-48%, p < 0.05), and proliferation rate (-35%, p < 0.001), colony formation capacity (-50%, p < 0.01), and GSH levels (-62%, p < 0.05). The negative effect of the FFAs of diabetic serum on the stemness characteristics may impair the regenerative capabilities of AdMSCs.

Molecular Mechanism of Lipotoxicity as an Interesting Aspect in the Development of Pathological States-Current View of Knowledge.

Free fatty acids (FFAs) play numerous vital roles in the organism, such as contribution to energy generation and reserve, serving as an essential component of the cell membrane, or as ligands for nuclear receptors. However, the disturbance in fatty acid homeostasis, such as inefficient metabolism or intensified release from the site of storage, may result in increased serum FFA levels and eventually result in ectopic fat deposition, which is unfavorable for the organism. The cells are adjusted for the accumulation of FFA to a limited extent and so prolonged exposure to elevated FFA levels results in deleterious effects referred to as lipotoxicity. Lipotoxicity contributes to the development of diseases such as insulin resistance, diabetes, cardiovascular diseases, metabolic syndrome, and inflammation. The nonobvious organs recognized as the main lipotoxic goal of action are the pancreas, liver, skeletal muscles, cardiac muscle, and kidneys. However, lipotoxic effects to a significant extent are not organ-specific but affect fundamental cellular processes occurring in most cells. Therefore, the wider perception of cellular lipotoxic mechanisms and their interrelation may be beneficial for a better understanding of various diseases’ pathogenesis and seeking new pharmacological treatment approaches.

Abstract 11606: Mature Ipsc-Derived Atrial Cardiomyocytes Show That Saturated Fatty Acids Differentially Modulate Ion Channel and Structural Remodeling in Obesity-Induced Atrial Fibrillation

Background: Obesity-induced atrial fibrillation (AF) is modulated in part by increased serum free fatty acids (FFA) and FA infiltration of the heart. Mass spectrometry data on obese mice have shown increased saturated FAs (SFA), monounsaturated FAs (MUFA), and polyunsaturated FAs (PUFA) compared to lean controls with the largest increase in the PUFA, linoleic acid (LA). Although reports suggest that some FAs induce ventricular arrhythmias in mice, the differential electrophysiological (EP) effects of SFAs, MUFAs, and PUFAs on the atria remain unclear. Objective: To determine if SFAs, MUFAs, and PUFAs differentially modulate atrial remodeling using mature human induced pluripotent stem-derived atrial cardiomyocytes (iPSC-aCMs) and HL1 cells. . Methods: We compared iPSC-aCMs and HL-1 cells treated with bovine serum albumin (BSA) with palmitic acid (PA), oleic acid (OA) and LA (600 uM each) for 1 week. Ion channel function was assessed using whole-cell patch clamping and we assessed β-oxidation and atrial remodeling with using ELISA, qPCR, and Western blotting. Results: iPSC-aCMs treated with PA, OA, and LA displayed higher expression of FABP3 , ANGPTL4 , and CPT1A suggesting increased FA metabolism and β-oxidation (Figure A-C). In HL1 cells, protein expression of Cpt1a was increased in all groups after FA treatment (Figure D). PA differentially modulated expression of Kv7.1 and NCX1 in HL1 cells (Figure E-F) and ion channel mRNA expression in iPSC-aCMs (Figure G-L). After 1 week PA and LA treatment β-adrenergic signaling was significantly increased in iPSC-aCMs while OA decreased it compared to controls (Figure M-O). Conclusions: Using mature iPSC-aCMs, we showed for the first time that SFA, MUFA, and PUFA not only increased FA metabolism but also differentially modulated ion channel and structural remodeling and β-adrenergic signaling in the atria. Our findings may have important implications for the management of obesity-induced AF in patients.

Enhanced Muscle Strength in Dyslipidemic Mice and Its Relation to Increased Capacity for Fatty Acid Oxidation.

Dyslipidemia is commonly linked to skeletal muscle dysfunction, accumulation of intramyocellular lipids, and insulin resistance. However, our previous research indicated that dyslipidemia in apolipoprotein E and low-density lipoprotein receptor double knock-out mice (ApoE/LDLR -/-) leads to improvement of exercise capacity. This study aimed to investigate in detail skeletal muscle function and metabolism in these dyslipidemic mice. We found that ApoE/LDLR -/- mice showed an increased grip strength as well as increased troponins, and Mhc2 levels in skeletal muscle. It was accompanied by the increased skeletal muscle mitochondria numbers (judged by increased citrate synthase activity) and elevated total adenine nucleotides pool. We noted increased triglycerides contents in skeletal muscles and increased serum free fatty acids (FFA) levels in ApoE/LDLR -/- mice. Importantly, Ranolazine mediated inhibition of FFA oxidation in ApoE/LDLR -/- mice led to the reduction of exercise capacity and total adenine nucleotides pool. Thus, this study demonstrated that increased capacity for fatty acid oxidation, an adaptive response to dyslipidemia leads to improved cellular energetics that translates to increased skeletal muscle strength and contributes to increased exercise capacity in ApoE/LDLR -/- mice.

Metabolic regulation of mitochondrial reactive oxygen species (mtROS) production and transient receptor potential vanilloid‐4 (TRPV4) activation in microvascular endothelial cells in PAH

Rationale In pulmonary arterial hypertension (PAH), highly proliferative microvascular endothelial cells (MVECs) are thought to contribute to vaso-occlusive lesion formation and increased pulmonary artery pressures. Using MVECs isolated from the Sugen/Hypoxia (SuHx) model of PAH, we recently showed that increased mtROS production activates the TRPV4 calcium channel and contributes to increased MVEC proliferation in vitro. However, the mechanistic basis for sustained mtROS production in MVECs isolated from SuHx rats (SuHx-MVECs) was unclear. Along with increased mtROS production, we observed evidence of significant mitochondrial dysfunction, including increased fragmentation and glycolytic shift. Since mtROS production can be increased by changes in the type of fuel (e.g. fatty acids)used to generate TCA metabolites, we hypothesized that use of non-glucose sources (specifically, increased fatty acid oxidation - FAO) could be the source of mitochondrial dysfunction and mtROS production in SuHx-MVECs. Methods Intracellular Ca2+ concentration ([Ca2+]i) was measured using Fura-2AM loaded MVEC in a flow chamber perfused with modified Krebs solution. Mitochondrial morphology was measured computationally using validated algorithms applied to confocal images of mitochondria in N- and SuHx-MVEC stained with MitoTracker. Lipid droplets were measured using BODIPY staining. Targeted metabolomics were performed on MVEC cell lysates using a standardized LC/MS approach as described previously (Suresh et al., AJP-Lung 2019). Human PAH metabolomics and genomics data were obtained from NIH Metabolomics Workbench or GEO Omnibus, respectively, and analyzed using R. Results Despite evidence of glycolytic shift (decreased oxygen consumption rate, increased extracellular acidification rate, increased extracellular lactate levels), levels of TCA metabolites, measured using targeted metabolomics, were not significantly lower in SuHx-MVECs compared to normoxic (N-MVEC) controls, suggesting presence of anaplerosis. Serum free fatty acids (FFA) were increased in SuHx rats at 5 weeks, while intracellular lipid droplet number was increased in SuHx-MVECs. Analysis of human PAH metabolomics and genomics data revealed increased serum FFA levels and increased expression of enzymes involved in breaking down long chain fatty acids for use in the TCA cycle (i.e. FAO). In SuHx-MVECs, untargeted metabolomics and metabolite-specific assays revealed increased levels of beta-hydroxybutyrate (BOHB), a ketone body produced by FAO. In N-MVECs, BOHB supplementation was sufficient to increase TRPV4 sensitivity to pharmacologic agonists. In contrast, inhibition of FAO (with Etoximir) in SuHx-MVECs attenuated basal Ca2+ and mitochondrial fragmentation to a similar extent as TRPV4 inhibition or mtROS quenching. Conclusion We conclude that intermediary signaling molecules such as BOHB and mtROS, produced as a consequence of increased FAO, act in concert to sensitize and activate the TRPV4 channel in lung MVECs. These data suggest an exciting role for metabolism as a regulator of TRPV4 channel activity in PAH.

Serum free fatty acid levels and insulin resistance in patients undergoing one-anastomosis gastric bypass.

IntroductionOne anastomosis gastric bypass (OAGB) leads to improvement in glucose homeostasis; however, the mechanism of this beneficial effect is not fully understood. Increased serum free fatty acid (FFA) concentrations in obese subjects contribute to the development of insulin resistance and type 2 diabetes.AimThe authors hypothesized that improvement in glucose homeostasis after OAGB may be associated with a decrease in FFA concentration.Material and methodsSerum FFA levels were measured by gas chromatography-mass spectrometry before and 3 months after OAGB and, for comparison, in patients who underwent laparoscopic sleeve gastrectomy (LSG). Serum insulin was assayed by immunoenzymatic method, and other parameters by standard laboratory methods.ResultsOAGB resulted in a large decrease in FFA levels and great improvement in insulin sensitivity. These effects in patients after LSG were less prominent.ConclusionsResults suggest that decreased serum FFA levels after OAGB contribute to resolution of insulin sensitivity after this type of bariatric surgery.

Contrast-enhanced ultrasound perfusion patterns and serum lipid signatures of vulnerable carotid artery plaque in predicting stroke: A cohort study of carotid stenosis in Chinese patients.

Early identification of vulnerable plaques at risk of rupture could help prevent cerebral ischemic stroke in patients with carotid artery disease. To investigate the correlation between contrast-enhanced ultrasound (CEUS) perfusion patterns and serum lipid signatures of carotid artery plaques with the degree of carotid stenosis. A total of 80 patients with carotid artery plaques who underwent CEUS were included. All patients underwent CEUS, computed tomography angiography or digital subtraction angiography, and serum lipid testing. The contrast agent enhancement levels and the CEUS perfusion patterns in the plaques were associated with the degree of carotid stenosis (P < 0.05). Serum free fatty acid (FFA) was associated with the contrast agent enhancement levels (P < 0.05), but did not correlate with the degree of stenosis (P > 0.05). There was no significant difference in total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and triglycerides with respect to contrast agent enhancement levels (P > 0.05) or the degree of stenosis (P > 0.05). A high level of CEUS perfusion and increased serum FFA levels are indicative of vulnerable carotid plaques, which may be useful for the prediction of stroke in patients with carotid artery disease.

SUN-603 Electronic Cigarette Exposure Induces Pro-Inflammatory Changes in Adipose Tissue in Apolipoprotein E (APOE) Knockout Mice

Electronic nicotine delivery systems or electronic cigarettes (e-cigarettes) are becoming exceptionally popular in the world as an alternative to conventional nicotine cigarettes, both in smokers and people who have never smoked. Nicotine can induce lipolysis in adipose tissue, leading to increased serum free fatty acids (FFA). Increased levels of FFA are one of the key elements in inducing a pro-inflammatory response and lead to ectopic lipid accumulation, lipotoxicity, mitochondrial dysfunction and metabolic disease. Our laboratory has shown that chronic e-cigarette exposure induces cardiac dysfunction, atherosclerosis and hepatic steatosis in the ApoE knockout (KO) model associated with increased levels of serum FFA. In this study, we investigated the role of adipose tissue in the metabolic changes associated with e-cigarette exposure. ApoE KO mice were exposed to saline, e-cigarette without nicotine [e-cigarette (0%)] and e-cigarette with 2.4% nicotine [e-cigarette (2.4%)] aerosol for 12 weeks. Western blot analyses from adipose tissue showed that mice treated with e-cigarette (2.4%) had decrease levels of SIRT1 when compared to mice treated with saline or e-cigarette (0%). Transcriptomic analysis of the differentially expressed genes shows a differential transcriptional response to e-cigarette (2.4%) in adipose tissue in comparison with e-cigarette (0%) or saline. The RNA-seq examination using ingenuity pathway analysis (IPA) software, revealed dysregulation of fibrosis, agranulocyte and granulocyte adhesion and diapedesis pathways in e-cigarette (2.4%) -exposed adipose tissue. Overall, we found an inflammatory phenotype associated with decreased levels of SIRT1 in adipose tissue of mice treated with e-cigarette (2.4%). Understanding the consequences of e-cigarette use on metabolic disease is directly relevant to the development of policies related to e-cigarette use.

Growth hormone upregulates ANGPTL4 mRNA and suppresses lipoprotein lipase via fatty acids: Randomized experiments in human individuals

ObjectivesLipoprotein lipase (LPL) catalyzes the hydrolysis of circulating triglycerides into free fatty acids (FFA) and thereby promotes FFA uptake in peripheral tissues. LPL is negatively regulated by angiopoietin-like protein 4 (ANGPTL4) presumably by an FFA-dependent mechanism. Growth hormone (GH) suppresses LPL activity, but it is unknown whether this is mediated by FFA and ANGPTL4. Therefore, we investigated the concerted effect of GH on ANGPTL4 and LPL in the presence and absence of lipolysis in two in vivo studies in human subjects. MethodsIn a randomized, placebo-controlled, cross-over study, nine obese men were examined after injection of 1) a GH bolus, and 2) a GH-receptor antagonist followed by four adipose tissue biopsies obtained over a 5-h period. In a second study, nine hypopituitary men were examined in a 2 × 2 factorial design including GH and acipimox (an anti-lipolytic agent), with biopsies from adipose tissue and skeletal muscle obtained during a basal period and a subsequent hyperinsulinemic-euglycemic clamp. The mRNA expression of ANGPTL4 and LPL as well as LPL activity were analyzed in the biopsies. ResultsIn both studies, GH increased serum FFA levels, upregulated ANGPTL4 mRNA expression and suppressed LPL activity. In study 2, acipimox completely suppressed FFA levels and antagonized the effects of GH on ANGPTL4 and LPL. ConclusionsThese human in vivo studies demonstrate that GH upregulates ANGPTL4 mRNA and suppresses LPL activity via an FFA-dependent mechanism.

Effect of Curcumin Supplement in Summer Diet on Blood Metabolites, Antioxidant Status, Immune Response, and Testicular Gene Expression in Hu Sheep

Simple SummaryHeat stress can induce oxidative stress and has an adverse effect on the growth and reproductive performance in animals. Curcumin, a plant-derived substance, with the effect of scavenging oxidative free radicals, improving immune response and anti-apoptosis, has been widely used as a dietary supplement in the livestock industry. The present study aims to investigate the effect of a curcumin dietary supplement on the blood metabolites, antioxidant status, immune response, and testicular gene expression in Hu Sheep in summer. The results show that dietary curcumin supplementation (450 and 900 mg/per sheep daily) can promote lipid metabolism, antioxidant capacity, and immune response as well as testicular development in Hu sheep, which provides evidence for the protective role of curcumin against heat stress in sheep.In summer, the high temperature affects animal growth and reproductive performance. Curcumin is a flavonoid with anti-oxidant and anti-inflammatory effects. To evaluate the effects of dietary curcumin supplement on the blood biochemical parameters and testicular gene expressions in Hu sheep in summer, a total of 144 male Hu sheep aged four months were randomly divided into three groups (Con, Cur1, and Cur2, n = 48). Sheep in Con, Cur1, and Cur2 groups were fed a basal diet supplement with 0, 450, and 900 mg (per sheep) curcumin daily, respectively. Sheep were fed for 35 days, including a pre-feed for seven days. The results showed that the supplement with 450 mg and 900 mg curcumin increased serum free fatty acid (NEFA) and glutathione peroxidase (GPX), as well as IgA and IgM. The supplement with 450 mg curcumin increased the IgG level, while the supplement with 900 mg curcumin had a lower IgG level than the supplement with 450 mg curcumin (p < 0.05). Dietary curcumin supplement increased testicular organ index, serum testosterone level, and testicular star mRNA expression (p < 0.05). Furthermore, dietary curcumin supplement linearly inhibited testicular apoptosis with increased testicular bcl-2 mRNA expression and decreased caspase-3 mRNA expression (p < 0.05). In conclusion, dietary curcumin supplement can promote lipid metabolism, antioxidant capacity, and immune response, as well as testicular development, in Hu sheep, which provides evidence of application of curcumin in sheep production.

SUN-067 E-cigarettes and High Fat Diet Cause Alteration in Cardiac Structure and Function

Smoking is the major cause of cardiovascular diseases (CVD) and is the single largest cause of death in the USA. Smoking cessation can reduce the mortality from CVD. Electronic cigarettes, also known as electronic nicotine delivery systems (ENDS), have been marketed as a smoking cessation device. In spite of the widespread use of ENDS and the proposed detrimental cardiac and atherosclerotic effects of nicotine, the effects of ENDS on these systems are not well known. Recently, using Apolipoprotein E null mice, we demonstrated that mice exposed to e-cigarettes have decreased cardiac fractional shortening and ejection fraction together with ventricular ultrastructural abnormalities indicative of cardiomyopathy in comparison with controls. In this study, we investigated the detrimental effects of ENDS at doses similar to the clinically relevant concentrations found in habitual smokers and a high fat diet (HFD) on cardiac structure and function in a commonly used model of diet-induced obesity. C57 BL6 mice fed HFD were exposed to ENDS in the presence (2.4%) or absence (0%) of nicotine and saline aerosol for 12 weeks. Mice exposed to ENDS (2.4%) had increased serum free fatty acid levels in comparison with saline and ENDS (0%). Echocardiographic data show that mice treated with ENDS (2.4%) had decreased left ventricular fractional shortening and ejection fraction compared to ENDS (0%) and saline. Transmission electron microscopy revealed that cardiomyocytes of mice treated with ENDS (2.4%) exhibited ventricular abnormalities, including lipid accumulation (ventricular steatosis), myofibrillar derangement and destruction, and mitochondrial hypertrophy. Additionally, ENDS (2.4%) also caused increased cardiac oxidative stress and triggered cardiomyocyte apoptosis. These results demonstrate profound adverse effects of ENDS on ventricular structure and function in obese mice. We surmise that ENDS exposure may cause heart failure and other forms of cardiomyopathy in obese patients. This is important information for patients that use ENDS and regulatory agencies that regulate ENDS.

Differential Effects of a Bout of Moderate‐intensity Physical Exercise on Adipose Tissue Inflammation in Lean and in Obese Mice

Inflammation is an adaptive response that is triggered by the noxious stimuli in order to maintain the homeostasis. Previous studies have shown that higher lipolysis rate after fasting is associated with the influx of leukocytes and increased cytokine levels in the epididymal adipose tissue (EAT). Fat mobilization is also highly activated during and post‐exercise. In spite of substantial evidences having supported the link between inflammation and exercise, the association between EAT, cytokines and acute exercise is less explored. Herein, we characterized the EAT inflammation following exercise in lean and obese mice. We used in vivo confocal imaging from EAT vessel to display the higher recruitment of neutrophils 0 and 6 hours post‐exercise in lean mice. Additionally, we found that exercise enhanced the levels of IL‐6 and TNF‐alpha in the EAT which were correlated with increased serum free fatty acids in lean mice. Interestingly, obese mice subjected to exercise showed lower pro‐inflammatory level of cytokines in the EAT and lost the correlation between IL‐6, TNF‐alpha and free fatty acids. Furthermore, obese mice increased IL‐10 24h post‐exercise. Together, our data show that exercise induces inflammation in the EAT in lean mice. These responses may have a physiological purpose and be important to stimulate fat breakdown. Conversely, exercise in obese mice promoted a reduction in pro‐inflammatory mediators and elevated IL‐10. Despite of the low‐grade inflammation being associated with metabolic dysfunctions, at least in part, the inflammatory milieu in EAT may be also important to regulate fat remodeling induced by exercise.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Effects of selenium on apoptosis and abnormal amino acid metabolism induced by excess fatty acid in isolated rat hepatocytes.

Increased serum free fatty acid (FFA) occurs in subjects with non-alcoholic fatty liver disease (NAFLD) and also triggers oxidative stress, apoptosis, and insulin resistance. Selenium (Se) is an antioxidant agent. However, the effect of Se on NAFLD or diabetes is still unclear. We investigated the effect of Se on apoptosis and abnormal amino acid metabolism initiated by excess FFA in isolated rat hepatocytes. Primary hepatocytes from rats were isolated and exposed to excessive FFA (0.5 mM oleate/palmitic acid 2:1) and 0.1 μM Se. Se protected primary hepatocytes against oxidative stress and apoptosis induced by excess FFA, but did not play a role on abnormal amino acid metabolism and insulin resistance initiated by FFA in isolated rat hepatocytes. Although Se had the capability of preventing the apoptosis initiated by ROS, insulin resistance failed to be reversed in hepatocytes exposed to FFA. This failure may be attributed to the limitation of Se in regulating branched chain amino acids abundance. This indicates that apoptosis and insulin resistance might be involved in different pathways when isolated hepatocytes were exposed to FFA and Se.

Adiponectin reduces ER stress-induced apoptosis through PPARα transcriptional regulation of ATF2 in mouse adipose.

Adiponectin is a cytokine produced predominantly by adipose tissue and correlates with glucose and lipid homeostasis. However, the effects of adiponectin on endoplasmic reticulum (ER) stress and apoptosis of adipose tissue remain elusive. In this study, we found that tunicamycin-induced ER stress increased serum free fatty acid (FFA) and impaired glucose tolerance, elevated the mRNA levels of GRP78, Chop, ATF2 and caspase 3, but reduced adiponectin mRNA level in white adipose tissue. Moreover, ER stress-triggered adipocyte apoptosis by increasing cellular FFA level and Ca2+ level. Further analysis revealed that adiponectin alleviated ER stress-induced adipocyte apoptosis by elevating peroxisome proliferator-activated receptor alpha (PPARα) mRNA level. Our data also confirmed that adiponectin reduced early apoptotic cells and blocked the mitochondrial apoptosis pathway by activating the AdipoR1/AMP-activated protein kinase (AMPK) signal pathway. In addition, PPARα bound to ATF2 promoter region and inhibited transcription of ATF2. The inhibition of adipocyte apoptosis by adiponectin was correlated with transcriptional suppression of ATF2. Furthermore, adiponectin inhibited ER stress-induced apoptosis by activating the AMPK/PKC pathway. In summary, our data demonstrate adiponectin inhibited ER stress and apoptosis of adipocyte in vivo and in vitro by activating the AMPK/PPARα/ATF2 pathway. Our study establishes that adiponectin is an important adipocytokine for preventing and treating obesity.

The effect of a negative energy balance status on β-carotene availability in serum and follicular fluid of nonlactating dairy cows

Maternal metabolic pressure due to a cow’s negative energy balance (NEB) has a negative effect on oocyte quality as a result of increased oxidative stress. In this study, we hypothesized that a NEB status may negatively affect the availability of β-carotene (bC, an antioxidant) in the micro-environment of the oocyte or follicular fluid (FF) and that daily bC supplementation can increase bC availability. We aimed to (1) determine the effect of a nutritionally induced NEB on bC concentrations in serum and FF as well as on the presence of bC metabolites, oxidative stress levels, and follicular growth in a nonlactating dairy cow model, and (2) investigate how this effect could be altered by dietary bC supplementation. Six multiparous nonlactating Holstein Friesian cows were subjected to 4 consecutive dietary treatments, 28 d each: (1) 1.2 × maintenance (M) or positive energy balance (PEB) without bC supplement (PEB-bC), (2) 1.2 × M with daily supplement of 2,000mg of bC comparable to the level of bC intake at grazing (PEB+bC), (3) 0.6 × M with 2,000mg of bC (NEB+bC), and (4) 0.6 × M (NEB-bC). At the end of each treatment, estrous cycles were synchronized and blood and FF of the largest follicle were sampled and analyzed for bC, retinol, α-tocopherol, free fatty acids, estradiol, and progesterone. Serum cholesterol, triglycerides, urea, insulin growth factor 1, growth hormone, total antioxidant status (TAS), and red blood cell glutathione (GSH) concentrations were determined as well. All cows lost body weight during both energy restriction periods and showed increased serum free fatty acid concentrations, illustrating a NEB. A dietary induced NEB reduced FF bC, but not plasma bC or plasma and FF retinol concentrations. However, bC and retinol concentrations drastically increased in both fluid compartments after bC supplementation. Follicular diameter was increased in supplemented PEB cows. Energy restriction reduced the TAS and red blood cell GSH, whereas daily bC supplementation could restore GSH concentrations, but not the TAS, to levels present in healthy PEB cows. In conclusion, daily bC supplementation can substantially improve bC and retinol availability in the oocyte’s micro-environment, irrespective of the energy balance, which may affect follicular development and oocyte quality in the presence of maternal metabolic stress. This knowledge can be of importance to optimize nutritional strategies in the dairy industry to feed for optimal oocyte quality and fertility.

Effects of reduced food intake on the parameters of toxicity evaluation in dogs.

It is crucial to evaluate the variations in the toxicity parameters in experimental animals during the development of new drugs. Reduced food intake has been reported to have an impact on the toxicity parameters in rats; however, there are few reports of such studies in dogs. The aim of this study was to clarify the effects of reduced food intake on the general toxicity parameters and their reversibility in dogs. Male beagle dogs were fed 300 g/day of diet for 12 weeks in the control group, and 150 g/day for the first 8 weeks and 200 g/day for the subsequent 4 weeks in the low feeding group. During the following 4-week recovery period, the amount of feeding was set at 300 g/day. There were no clinical changes in any of the dogs. The low feeding group showed a body weight loss of 9.0%, 16.7% and 14.3% relative to the pre-test values at Week 4, 8 and 12, respectively. The following changes from the pre-test values and/or the control group in the examined parameters were observed in this group: decreased heart rate, prolonged PR interval on the ECG, decreased leukocyte count, and increased serum free fatty acid and γ-glutamyl transpeptidase levels. Significant changes of these parameters were not observed any more during the recovery period. This fact supports biological or physiological reaction to reduced food intake. These results are considered to represent useful information for toxicologists to distinguish between the direct effects of drugs and the changes attributable to reduced food intake.