Increased Plasma Free Fatty Acid Research Articles

Peripheral insulin resistance is early, progressive, and correlated with cachexia in Walker-256 tumor-bearing rats.

Insulin (INS) resistance is often found in cancer-bearing, but its correlation with cachexia development is not completely established. This study investigated the temporal sequence of the development of INS resistance and cachexia to establish the relationship between these factors in Walker-256 tumor-bearing rats (TBrats). INS hepatic sensitivity and INS resistance-inducing factors, such as free fatty acids (FFA) and tumor necrosis factor-α (TNF-α), were also evaluated. Studies were carried out on Days 2, 5, 8, and/or 12 after inoculation of tumor cells in rats. The peripheral INS sensitivity was assessed by theINS tolerance testand the INS hepatic sensitivity in in situ liver perfusion. TBrats with 5, 8, and 12 days of tumor, but not 2 days, showed decreased peripheral INS sensitivity (INS resistance), retroperitoneal fat, and body weight, compared to healthy rats, which were more pronounced on Day 12. Gastrocnemius muscle wasting was observed only on Day 12 of tumor. The peripheral INS resistance was significantly correlated (r = -.81) with weight loss. Liver INS sensitivity of TBrats with 2 and 5 days of tumor was unchanged, compared to healthy rats. TBrats with 12 days of tumor showed increased plasma FFA and increased TNF-α in retroperitoneal fat and liver, but not in the gastrocnemius, compared to healthy rats. In conclusion, peripheral INS resistance is early, starts along with fat and weight loss and before muscle wasting, progressive, and correlated with cachexia, suggesting that it may play an important role in the pathogenesis of the cachectic process in TBrats. Therefore, early correction of INS resistance may be a therapeutic approach to prevent and treat cancer cachexia.

Distinct Mechanisms Responsible for the Increase in Glucose Production and Ketone Formation Caused by Empagliflozin in T2DM Patients.

To examine the mechanisms responsible for the increase in glucose and ketone production caused by empagliflozin in patients with type 2 diabetes mellitus (T2DM). Twelve subjects with T2DM participated in two studies performed in random order. In study 1, endogenous glucose production (EGP) was measured with 8-h infusion of 6,6,D2-glucose. Three hours after the start of 6,6,D2-glucose infusion, subjects ingested 25 mg empagliflozin (n = 8) or placebo (n = 4), and norepinephrine (NE) turnover was measured before and after empagliflozin ingestion with 3H-NE infusion. Study 2 was similar to study 1 but performed under pancreatic clamp conditions. When empagliflozin was ingested under fasting conditions, EGP increased by 31% in association with a decrease in plasma glucose (-34 mg/dL) and insulin (-52%) concentrations and increases in plasma glucagon (+19%), free fatty acid (FFA) (+29%), and β-hydroxybutyrate (+48%) concentrations. When empagliflozin was ingested under pancreatic clamp conditions, plasma insulin and glucagon concentrations remained unchanged, and the increase in plasma FFA and ketone concentrations was completely blocked, while the increase in EGP persisted. Total-body NE turnover rate was greater in subjects receiving empagliflozin (+67%) compared with placebo under both fasting and pancreatic clamp conditions. No difference in plasma NE concentration was observed in either study. The decrease in plasma insulin and increase in plasma glucagon concentration caused by empagliflozin is responsible for the increase in plasma FFA concentration and ketone production. The increase in EGP caused by empagliflozin is independent of the change in plasma insulin or glucagon concentrations and is likely explained by the increase in NE turnover.

Metabolism-dependent ferroptosis promotes mitochondrial dysfunction and inflammation in CD4+ T lymphocytes in HIV-infected immune non-responders.

HIV immune non-responders (INRs) are described as a failure to reestablish a pool of CD4+ Tlymphocytes (CD4 cells) after antiretroviral therapy (ART), which is related to poor clinical results. Ferroptosis is a newly discovered form of cell death characterised by iron-dependent lipid peroxidation and the accumulation of reactive oxygen species (ROS). The mechanism of unrecoverable CD4 cells in INRs and whether ferroptosis plays a role are not fully understood. Ninety-two people living with HIV (PLHIVs) who experienced four-year ART with sustained viral suppression, including 27 INRs, 34 partial responders (PRs), and 31 complete responders (CRs); and 26 uninfected control participants (UCs) were analysed for 16 immune parameters with flow cytometry. Then plasma lipid, iron and oxidation, and antioxidant indicators were detected by ELISA, and CD4 cells were sorted out and visualised under transmission electron microscopy. Finally, ferroptosis inhibitors were added, and alterations in CD4 cell phenotype and function were observed. We found decreased recent thymic emigrants (RTE), over-activation and over-proliferation phenotypes, diminished killing function, decreased IL-7R and more severe inflammation; increased lipid peroxidation in the mitochondria and disruptions of the mitochondrial structure, showing typical features of ferroptosis in CD4 cells in INRs. Additionally, ferroptosis inhibitors could reduce inflammation and repair mitochondrial damage. Meanwhile, ELISA results showed increased plasma free fatty acids (FFA) and an imbalance of oxidative and antioxidant systems in INRs. Flow cytometry results displayed alterations of both transferrin receptor (CD71) and lipid transporter (CD36) expressions on the surface of CD4 cells. Mechanistically, there was a stronger correlation between CD36 expression and mitochondrial lipid peroxidation production, ferroptosis makers, and inflammation indicators; while amino acid transporter (CD98) was more related to killing functions; and CD71 was more closely related to activation status in CD4 cells. Cellular metabolism was closely correlated with its diverse functions in INRs. Ferroptosis was observed in CD4 cells of INRs, and inhibiting ferroptosis through modulating mitochondrial disorders and inflammation may offer an alternative immunological strategy for reinvigorating CD4 cells in INRs. This research was supported by the 13th Five-year Plan, Ministry of Science and Technology of China (2018ZX10302-102), Beijing Municipal Administration of Hospitals' Ascent Plan (DFL20191802), and Beijing Municipal Administration of Hospitals Clinical Medicine Development of Special Funding Support (ZYLX202126).

ANGPTL4, IL-6 and TNF-α as regulators of lipid metabolism during a marathon run

The aim of the study was to reveal whether marathon running influences regulators of lipid metabolism i.e. angiopoietin-like protein 4 (ANGPTL4), interleukin 6 (IL-6) and tumor necrosis factor-α (TNF-α). Plasma concentration of ANGPTL4, IL-6, TNF-α and lipids were determined in samples collected from 11 male runners before the marathon, immediately after the run and at 90 min of recovery. Plasma ANGPTL4 increased during exercise from 55.5 ± 13.4 to 78.1 ± 15.0 ng/ml (P < 0.001). This was accompanied by a significant increase in IL-6, TNF-α, free fatty acids (FFA) and glycerol (Gly) and a decrease in triacylglycerols (TG). After 90 min of recovery ANGPTL4 and TG did not differ from the exercise values, while plasma IL-6, TNF-α, FFA and Gly concentration were significantly lower. The exercise-induced increase in plasma concentration of ANGPTL4 correlated positively with the rise in plasma IL-6, TNF-α, FFA and Gly and negatively with the duration of the run. The increase in plasma IL-6 and TNF-α correlated positively with the rise in Gly. Summarizing, marathon running induced an increase in plasma ANGPTL4 and the value was higher in faster runners. The increase in plasma FFA, IL-6 and TNF-α concentration during a marathon run may be involved in plasma ANGPTL4 release, which could be a compensatory mechanism against FFA-induced lipotoxicity and oxidative stress. All of the analyzed cytokines may stimulate lipolysis during exercise.

Fasting Substrate Concentrations Predict Cardiovascular Outcomes in the CANagliflozin cardioVascular Assessment Study (CANVAS).

To examine whether the circulating substrate mix may be related to the incidence of heart failure (HF) and cardiovascular (CV) mortality and how it is altered by canagliflozin treatment. We measured fasting glucose, free fatty acids (FFA), glycerol, β-hydroxybutyrate, acetoacetate, lactate, and pyruvate concentrations in 3,581 samples from the CANagliflozin cardioVascular Assessment Study (CANVAS) trial at baseline and at 1 and 2 years after randomization. Results were analyzed by univariate and multivariate Cox proportional hazards models. Patients in the lowest baseline FFA tertile were more often men with a longer duration of type 2 diabetes (T2D), higher urinary albumin excretion, lower HDL-cholesterol levels, higher history of CV disease (CVD), and higher use of statins and insulin. When all seven metabolites were used as predictors, FFA were inversely associated with incident hospitalized HF (hazard ratio [HR] 0.33 [95% CI 0.21-0.55]), while glycerol was a positive predictor (2.21 [1.45-3.35]). In a model further adjusted for 16 potential confounders, including prior HF and CVD and pharmacologic therapies, FFA remained a significant negative predictor. FFA and glycerol also predicted CV mortality (HR 0.53 [95% CI 0.35-0.81] and 1.81 [1.26-2.58], respectively) and all-cause death (0.50 [0.36-0.70] and 1.64 [1.22-2.18]). When added to these models, background insulin therapy was an independent positive predictor of risk of death. Canagliflozin treatment significantly increased plasma FFA and β-hydroxybutyrate regardless of background antihyperglycemic therapy. A constitutive metabolic setup consisting of higher lipolysis may be beneficial in delaying or preventing hospitalized HF; a further stimulation of lipolysis by canagliflozin may reinforce this influence.

1411-P: Increased 24-Hour Plasma Free Fatty Acids in People with Obesity and Prediabetes

The importance of increased plasma free fatty acids (FFAs) in the pathogenesis of insulin resistance in people with prediabetes is unclear. It has been proposed that the increase in plasma insulin associated with obesity should be adequate to suppress adipose tissue lipolytic rates and maintain normal plasma FFA levels. We evaluated serial plasma FFA concentrations for 24 h in 20 adults with obesity and normal fasting glucose and glucose tolerance (metabolically healthy obesity [MHO]) and 20 adults with prediabetes, matched on age, sex, BMI and percent body fat with the MHO group. Insulin sensitivity, assessed as the glucose infusion rate during an insulin clamp, was greater in the MHO than the prediabetes group (48.1 ± 3.0 vs. 23.5 ± 1.3 μmol/kg fat-free mass/min, respectively, P &amp;lt; 0.0001) . Plasma FFA were greater throughout 24 h in the prediabetes group than the MHO group (Figure) . The 24-h areas under the curve were greater for plasma FFA (5.59 ± 0.37 vs. 4.58 ± 0.30 mmol/L x hour, P = 0.04) and plasma insulin (13,5± 1720 vs. 6,541 ± 558 pmol/L x hour, P = 0.0004) in the prediabetes group than the MHO group. We conclude that plasma FFA concentrations are greater throughout the day in people with prediabetes than those with MHO, despite a marked increase in plasma insulin concentration in those with prediabetes. These data support the notion that increased 24-h plasma FFAs contribute to insulin resistance associated with obesity. Disclosure M.C.Petersen: None. S.S.Farabi: n/a. G.Smith: None. S.Klein: Advisory Panel; Altimmune, Consultant; Janssen Research &amp; Development, LLC, ProSciento, Research Support; Janssen Research &amp; Development, LLC. Funding NIH T32DK007120Endocrine Fellows Foundation

Increased plasma fatty acid clearance, not fatty acid concentration, is associated with muscle insulin resistance in people with obesity

BackgroundAlthough it is well-accepted that increased plasma free fatty acid (FFA) concentration causes lipid overload and muscle insulin resistance in people with obesity, plasma FFA concentration poorly predicts insulin-resistant glucose metabolism. It has been proposed that hyperinsulinemia in people with obesity sufficiently inhibits adipose tissue triglyceride lipolysis to prevent FFA-induced insulin resistance. However, we hypothesized enhanced FFA clearance in people with obesity, compared with lean people, prevents a marked increase in plasma FFA even when FFA appearance is high. MethodsWe assessed FFA kinetics during basal conditions and during a hyperinsulinemic-euglycemic clamp procedure in 14 lean people and 46 people with obesity by using [13C]palmitate tracer infusion. Insulin-stimulated muscle glucose uptake rate was evaluated by dynamic PET-imaging of skeletal muscles after [18F]fluorodeoxyglucose injection. ResultsPlasma FFA clearance was accelerated in participants with obesity and correlated negatively with muscle insulin sensitivity without a difference between lean and obese participants. Furthermore, insulin infusion increased FFA clearance and the increase was greater in obese than lean participants. ConclusionsOur findings suggest plasma FFA extraction efficiency, not just plasma FFA concentration, is an important determinant of the cellular fatty acid load and the stimulatory effect of insulin on FFA clearance counteracts some of its antilipolytic effect.

Peak Fat Oxidation Rate Is Closely Associated With Plasma Free Fatty Acid Concentrations in Women; Similar to Men.

Introduction: In men, whole body peak fat oxidation (PFO) determined by a graded exercise test is closely tied to plasma free fatty acid (FFA) availability. Men and women exhibit divergent metabolic responses to fasting and exercise, and it remains unknown how the combined fasting and exercise affect substrate utilization in women. We aimed to investigate this, hypothesizing that increased plasma FFA concentrations in women caused by fasting and repeated exercise will increase PFO during exercise. Then, that PFO would be higher in women compared with men (data from a previous study).Methods: On two separate days, 11 young endurance-trained women were investigated, either after an overnight fast (Fast) or 3.5 h after a standardized meal (Fed). On each day, a validated graded exercise protocol (GXT), used to establish PFO by indirect calorimetry, was performed four times separated by 3.5 h of bed rest both in the fasted (Fast) or fed (Fed) state.Results: Peak fat oxidation increased in the fasted state from 11 ± 3 (after an overnight fast, Fast 1) to 16 ± 3 (mean ± SD) mg/min/kg lean body mass (LBM) (after ~22 h fast, Fast 4), and this was highly associated with plasma FFA concentrations, which increased from 404 ± 203 (Fast 1) to 865 ± 210 μmol/L (Fast 4). No increase in PFO was found during the fed condition with repeated exercise. Compared with trained men from a former identical study, we found no sex differences in relative PFO (mg/min/kg LBM) between men and women, in spite of significant differences in plasma FFA concentrations during exercise after fasting.Conclusion: Peak fat oxidation increased with fasting and repeated exercise in trained women, but the relative PFO was similar in young trained men and women, despite major differences in plasma lipid concentrations during graded exercise.

Hepatocyte‐specific Overexpression of Fatty Acid Desaturase 1 Improves Insulin Signaling and ameliorates hypertriglyceridemia in Male Rat

Objective Decreased fatty acid desaturase 1 (Fads1) activity results in the accumulation of saturated fat, which contributes to the development of nonalcoholic steatohepatitis (NASH). The aim of this study was to determine whether hepatic overexpression of Fads1 attenuates a dietary high-fat high-fructose (HFHF)-induced metabolic phenotype. Methods Hepatocyte-specific overexpression of Fads1 was achieved via the tail vein injection of recombinant adeno-associated virus (AAV) serotype 8 containing an albumin promoter with rat Fads1 sequence. Blank vectors served as controls. Male weanling Sprague-Dawley rats were assigned to five groups and fed with chow diet, low-fat high-fructose diet with AAV8 blank control (LFHF-AAV8-Blank), LFHF-AAV8-Fads1, high-fat high-fructose diet with AAV8 blank control (HFHF-AAV8-Blank), or HFHF-AAV8-Fads1 (n=8 rats/group) for 8 weeks. Metabolic phenotypes were characterized, including body weight, level of hepatic steatosis, glucose and insulin tolerance tests (GTT, ITT). Liver, skeletal muscle and adipose tissue insulin signaling were examined by western blot. Results Hepatocyte-specific overexpression of Fads1 significantly decreased body weight gain and improved glucose tolerance, but not hepatic steatosis, in LFHF-fed rats. These effects were not evident in HFHF-fed rats. On the contrary, white adipose tissue weight was markedly reduced in HFHF-AAV8-Fads1 rats compared to HFHF-AAV8-blank control rats, and to a lesser extent in LFHF rats. Both LFHF-AAV8-Fads1 and HFHF-AAV8-Fads1 rats displayed decreased fasting plasma triglycerides and increased plasma free fatty acids compared to their AAV8-blank control rats, and this was associated with upregulation of adipose tissue hormone sensitive lipase (HSL). While phosphorylated Akt (p-Akt) expression was downregulated, phosphorylated glycogen synthase kinase 3β (GSK-3β) was upregulated by both LFHF and HFHF diet in skeletal muscle, these alterations were not evident in the liver and adipose tissue. Moreover, decreased expression of p-Akt in skeletal muscle was partially restored in HFHF-AAV8-Fads1 rats, but not in LFHF-AAV8-Fads1 rats. Conclusion Our data demonstrated that hepatocyte-specific overexpression of Fads1 leads to the improvement of metabolic phenotypes in a diet- and tissue-specific manner, and this was associated with improved insulin signaling in skeletal muscle. The underlying mechanism(s) need further investigation.

Acute Effect of Coconut Oil on Peak Forearm Blood Flow in Healthy Men: A Randomized Crossover Trial

Background: A high-fat meal can induce vascular dysfunction. Despite containing a high amount of saturated fats, coconut oil is claimed to have cardiovascular health benefits. However, the information regarding the acute effect of coconut oil on vascular function in humans is unknown. Objective: To determine the effects of coconut oil ingestion experiment (Coco) on peak forearm blood flow (FBFpeak) and plasma biomarkers in healthy subjects. Materials and Methods: Seventeen healthy young men completed two separate experimental visits, Coco and control experiment (Con) in random order. The outcomes were FBFpeak measured by venous occlusion plethysmography and biomarkers as plasma triglycerides, free fatty acids, and malondialdehyde. The outcomes were collected at baseline (12 hour fasting), 2-hour and 4-hour after Coco (45 mL) in the Coco visit and at the same timeline in the control visit. Statistical analyses were performed to compare the data between the two experimental groups and within the group. Results: FBFpeak at 4-hour was significantly increased from the baseline (24.2±4.7 versus 21.7±3.8 mL/100 mL tissue.minute, p=0.009). Plasma triglycerides at 2-hour (75±25 mg/dL, p=0.03) and 4-hour (72±22 mg/dL, p=0.039) were significantly increased from the baseline (65±20 mg/dL). Coco significantly increased plasma free fatty acids at 2-hour (125.1±60.3 μEq/L, p=0.042) and at 4-hour (166.9±35.3 μEq/L, p&lt;0.001) compared to the baseline (87.2±34.0 μEq/L). There were no significant changes in vascular resistance and plasma malondialdehyde. Conclusion: Coconut oil augmented vascular function in healthy young men by increasing FBFpeak despite the accompanying postprandial elevations of plasma triglycerides and free fatty acids. Keywords: Virgin coconut oil, Peak forearm blood flow, Vascular function, Saturated fatty acid, Medium chain triglyceride

Effects of pre- and postpartum dietary starch content on productivity, plasma energy metabolites, and serum inflammation indicators of dairy cows

The objective of this study was to evaluate the effects of the starch content of pre- and postpartum diets on productivity, plasma energy metabolites, and serum markers of inflammation of dairy cows during the calving transition period. Eighty-eight primiparous and multiparous cows were randomly assigned to pre- and postpartum dietary treatments balanced for parity and pretrial body condition score at d 28 ± 3 before expected calving date. Cows were fed either a control [Control; 14.0% starch, dry matter (DM) basis] or high-starch (High; 26.1% starch, DM basis) prepartum diet commencing 28 ± 3 d before expected calving date. Following calving, cows were fed either a high-fiber (HF; 33.8% neutral detergent fiber, 25.1% starch, DM basis) or high-starch (HS; 27.2% neutral detergent fiber, 32.8% starch, DM basis) postpartum diet for the first 20 ± 2 d following calving. Cows fed the High prepartum diet had greater DM intake (12.4 vs. 10.2 kg/d), plasma concentrations of insulin (1.72 vs. 14.2 ng/mL), glucose (68.1 vs. 65.0 mg/dL), and glucagon-like peptide-2 (0.41 vs. 0.32 ng/mL) before parturition, but increased plasma free fatty acid concentration (452 vs. 363 µEq/L) and milk fat yield (1.64 vs. 1.48 kg/d) after parturition. Cows fed the HS postpartum diet had lower plasma free fatty acid (372 vs. 442 µEq/L) and serum haptoglobin (0.46 vs. 0.70 mg/mL) concentrations over a 3-wk period after calving. In addition, there was a tendency for interaction between prepartum and postpartum diets for milk yield, where feeding the HS postpartum diet increased milk yield compared with the HF diet for cows fed the Control prepartum diet (40.8 vs. 37.9 kg/d) but not for cows fed the High prepartum diet. These results suggest that management efforts to minimize the change in diet fermentability during the calving transition by feeding the High prepartum diet, the HF postpartum diet, or both did not increase productivity of dairy cows but increased fat mobilization after calving. Our findings also suggest that feeding high-starch postpartum diets can decrease fat mobilization and serum indicators of systemic inflammation and increase milk production even with the transition from a low-starch prepartum diet.

Two-Week Isocaloric Time-Restricted Feeding Decreases Liver Inflammation without Significant Weight Loss in Obese Mice with Non-Alcoholic Fatty Liver Disease.

Prolonged, isocaloric, time-restricted feeding (TRF) protocols can promote weight loss, improve metabolic dysregulation, and mitigate non-alcoholic fatty liver disease (NAFLD). In addition, 3-day, severe caloric restriction can improve liver metabolism and glucose homeostasis prior to significant weight loss. Thus, we hypothesized that short-term, isocaloric TRF would improve NAFLD and characteristics of metabolic syndrome in diet-induced obese male mice. After 26 weeks of ad libitum access to western diet, mice either continued feeding ad libitum or were provided with access to the same quantity of western diet for 8 h daily, over the course of two weeks. Remarkably, this short-term TRF protocol modestly decreased liver tissue inflammation in the absence of changes in body weight or epidydimal fat mass. There were no changes in hepatic lipid accumulation or other characteristics of NAFLD. We observed no changes in liver lipid metabolism-related gene expression, despite increased plasma free fatty acids and decreased plasma triglycerides in the TRF group. However, liver Grp78 and Txnip expression were decreased with TRF suggesting hepatic endoplasmic reticulum (ER) stress and activation of inflammatory pathways may have been diminished. We conclude that two-week, isocaloric TRF can potentially decrease liver inflammation, without significant weight loss or reductions in hepatic steatosis, in obese mice with NAFLD.

Probing metabolic memory in the hepatic response to fasting.

Tissues may respond differently to a particular stimulus if they have been previously exposed to that same stimulus. Here, we tested the hypothesis that a strong metabolic stimulus such as fasting may influence the hepatic response to a subsequent fast and thus elicit a memory effect. Overnight fasting in mice significantly increased plasma free fatty acids, glycerol, β-hydroxybutyrate, and liver triglycerides, and decreased plasma glucose, plasma triglycerides, and liver glycogen levels. In addition, fasting dramatically changed the liver transcriptome, upregulating genes involved in gluconeogenesis and in uptake, oxidation, storage, and mobilization of fatty acids, and downregulating genes involved in fatty acid synthesis, fatty acid elongation/desaturation, and cholesterol synthesis. Fasting also markedly impacted the liver metabolome, causing a decrease in the levels of numerous amino acids, glycolytic-intermediates, TCA cycle intermediates, and nucleotides. However, these fasting-induced changes were unaffected by two previous overnight fasts. Also, no significant effect was observed of prior fasting on glucose tolerance. Finally, analysis of the effect of fasting on the transcriptome in hepatocyte humanized mouse livers indicated modest similarity in gene regulation in mouse and human liver cells. In general, genes involved in metabolic pathways were upregulated or downregulated to a lesser extent in human liver cells than in mouse liver cells. In conclusion, we found that previous exposure to fasting in mice did not influence the hepatic response to a subsequent fast, arguing against the concept of metabolic memory in the liver. Our data provide a useful resource for the study of liver metabolism during fasting.

Somatotropin increases plasma ceramide in relation to enhanced milk yield in cows

Recombinant bovine somatotropin (rBST) changes metabolism to spare glucose for milk synthesis in cows. Ceramides inhibit insulin responsiveness in bovine adipocytes and are associated with insulin resistance and milk production in cows. The mechanisms by which rBST supports lactation may involve ceramide. Eight multiparous lactating Holstein cows were enrolled in a 2 × 2 replicated Latin square design with 14-d periods. Cows received a single rBST injection (Posilac; Elanco Animal Health, Indianapolis, IN; 0.062 mg/kg BW) or no injection (CON). An epinephrine challenge, insulin tolerance test, and liver biopsy were performed. Somatotropin enhanced the conversion of feed nutrients into milk components and increased plasma free fatty acid (FFA) concentrations (P < 0.01). Area-under-the-curves for FFA in response to epinephrine and insulin were greater in rBST-treated cows. In response to insulin, glucose concentrations (20- and 30-min post-challenge) and insulin area-under-the-curve were higher with rBST treatment (P < 0.05, <0.10, and <0.01), suggesting insulin resistance. Somatotropin modified the plasma lipidome. For example, rBST decreased plasma di- and triacylglycerol levels (eg, DG-50:1 and TG-18:0/16:0/16:1), phosphatidylcholines and sphingomyelins (P < 0.05). Somatotropin increased plasma total and very-long-chain (C22:0-, C24:0-, C26:0-) ceramide concentrations (P < 0.01). Liver ceramide concentrations were not modified. Plasma ceramides were positively correlated with circulating FFA (r ~ 0.57; P < 0.05) and milk yield (r ~ 0.63; P < 0.05). We conclude that rBST administration modifies the bovine lipidome and increases plasma ceramide concentrations in association with increased milk production in cows.

The Effect of the Short‐Term Growth Hormone Administration on Non‐Alcoholic Fatty Liver Disease in Diet‐Induced Obesity Models

Non‐alcoholic fatty liver disease (NAFLD) is one of the characteristics of metabolic syndrome. Most people are facing NAFLD whether they are diagnosed with obesity or not. Additionally, growth hormone (GH) administration could mediate the storage of body fat, including in the liver, as a result of the lipolytic effect. In obese patients, the reduction of GH level has been reported. The long‐term treatment of obesity with GH has been shown to reduce body fat mass as well as its well‐known effect to counteract insulin action, leading to insulin resistance. However, this remains unknown whether the short‐term GH administration can alter the fat storage in the liver while it does not worsen insulin sensitivity. To investigate this hypothesis, the rats were fed with either high‐fat (HF) or standard diet for 6 weeks, resulting in diet‐induced obesity (DIO) or diet‐resistant (DR) rats. The effect of short‐term GH treatment (1 mg/kg, twice daily, subcutaneous injection) was then assessed and compared to saline treatment after 3‐day of GH administration. A glucose tolerance test was performed after GH treatment to assess insulin sensitivity in vivo. After euthanasia, the liver was weighed and collected to measure triglyceride concentration by colorimetric assay. Blood was also collected to determine plasma free fatty acid (FFA) levels for the measurement of the lipolytic activity of GH. The results revealed that the percentage of liver mass was significantly greater in DIO and DR rats compared to control rats (p&lt;0.05). The short‐term GH administration did not alter the percentage of liver weight. For liver triglyceride level, DIO and DR rats had a higher level than that of control rats (p&lt;0.05); however, the liver triglyceride level did not affect by the short‐term GH treatment in all rats. Interestingly, the short‐term GH administration significantly increased plasma FFA only in DR rats (p&lt;0.05). Moreover, the effect of GH significantly improved glucose tolerance especially in DIO rats (p&lt;0.01), whereas it did not significantly affect insulin sensitivity in control and DR rats. Taken together, this study suggested that the short‐term GH administration may influence liver lipid metabolism in DR rats. However, further studies are required to determine whether short‐term GH administration affected liver lipid metabolism by interfering with the gene expression, including lipid uptake, lipid synthesis, and lipid oxidation. Additionally, the mechanisms underlying the effect of the short‐term GH administration on insulin sensitivity remains the subject for further studies.

Stroke Induces Prolonged Changes in Lipid Metabolism, the Liver and Body Composition in Mice

During recovery, stroke patients are at risk of developing long-term complications that impact quality of life, including changes in body weight and composition, depression and anxiety, as well as an increased risk of subsequent vascular events. The aetiologies and time-course of these post-stroke complications have not been extensively studied and are poorly understood. Therefore, we assessed long-term changes in body composition, metabolic markers and behaviour after middle cerebral artery occlusion in mice. These outcomes were also studied in the context of obesity, a common stroke co-morbidity proposed to protect against post-stroke weight loss in patients. We found that stroke induced long-term changes in body composition, characterised by a sustained loss of fat mass with a recovery of lean weight loss. These global changes in response to stroke were accompanied by an altered lipid profile (increased plasma free fatty acids and triglycerides) and increased adipokine release at 60 days. After stroke, the liver also showed histological changes indicative of liver damage and a decrease in plasma alanine aminotransferase (ALT) was observed. Stroke induced depression and anxiety-like behaviours in mice, illustrated by deficits in exploration, nest building and burrowing behaviours. When initial infarct volumes were matched between mice with and without comorbid obesity, these outcomes were not drastically altered. Overall, we found that stroke induced long-term changes in depressive/anxiety-like behaviours, and changes in plasma lipids, adipokines and the liver that may impact negatively on future vascular health.

Effect of mountain ultra-marathon running on plasma angiopoietin-like protein 4 and lipid profile in healthy trained men

PurposeAngiopoietin-like protein 4 (ANGPTL4) regulates lipid metabolism by inhibiting lipoprotein lipase activity and stimulating lipolysis in adipose tissue. The aim of this study was to find out whether the mountain ultra-marathon running influences plasma ANGPTL4 and whether it is related to plasma lipid changes.MethodsTen healthy men (age 31 ± 1.1 years) completed a 100-km ultra-marathon running. Plasma ANGPTL4, free fatty acids (FFA), triacylglycerols (TG), glycerol (Gly), total cholesterol (TC), low (LDL-C) and high (HDL-C) density lipoprotein-cholesterol were determined before, immediately after the run and after 90 min of recovery.ResultsPlasma ANGPTL4 increased during exercise from 68.0 ± 16.5 to 101.2 ± 18.1 ng/ml (p < 0.001). This was accompanied by significant increases in plasma FFA, Gly, HDL-C and decreases in plasma TG concentrations (p < 0.01). After 90 min of recovery, plasma ANGPTL4 and TG did not differ significantly from the exercise values, while plasma FFA, Gly, TC and HDL-C were significantly lower than immediately after the run.TC/HDL-C and TG/HDL-C molar ratios were significantly reduced. The exercise-induced changes in plasma ANGPTL4 correlated positively with those of FFA (r = 0.73; p < 0.02), and HDL-C (r = 0.69; p < 0.05). Positive correlation was found also between plasma ANGPTL4 and FFA concentrations after 90 min of recovery (r = 0.77; p < 0.01).ConclusionsThe present data suggest that increase in plasma FFA during mountain ultra-marathon run may be involved in plasma ANGPTL4 release and that increase in ANGPTL4 secretion may be a compensatory mechanism against fatty acid-induced oxidative stress. Increase in plasma HDL-C observed immediately after the run may be due to the protective effect of ANGPTL4 on HDL.

Fasting reveals largely intact systemic lipid mobilization mechanisms in respiratory chain complex III deficient mice

Mice homozygous for the human GRACILE syndrome mutation (Bcs1lc.A232G) display decreased respiratory chain complex III activity, liver dysfunction, hypoglycemia, rapid loss of white adipose tissue and early death. To assess the underlying mechanism of the lipodystrophy in homozygous mice (Bcs1lp.S78G), these and wild-type control mice were subjected to a short 4-hour fast. The homozygotes had low baseline blood glucose values, but a similar decrease in response to fasting as in wild-type mice, resulting in hypoglycemia in the majority. Despite the already depleted glycogen and increased triacylglycerol content in the mutant livers, the mice responded to fasting by further depletion and increase, respectively. Increased plasma free fatty acids (FAs) upon fasting suggested normal capacity for mobilization of lipids from white adipose tissue into circulation. Strikingly, however, serum glycerol concentration was not increased concomitantly with free FAs, suggesting its rapid uptake into the liver and utilization for fuel or gluconeogenesis in the mutants. The mutant hepatocyte mitochondria were capable of responding to fasting by appropriate morphological changes, as analyzed by electron microscopy, and by increasing respiration. Mutants showed increased hepatic gene expression of major metabolic controllers typically associated with fasting response (Ppargc1a, Fgf21, Cd36) already in the fed state, suggesting a chronic starvation-like metabolic condition. Despite this, the mutant mice responded largely normally to fasting by increasing hepatic respiration and switching to FA utilization, indicating that the mechanisms driving these adaptations are not compromised by the CIII dysfunction. Summary statementBcs1l mutant mice with severe CIII deficiency, energy deprivation and post-weaning lipolysis respond to fasting similarly to wild-type mice, suggesting largely normal systemic lipid mobilization and utilization mechanisms.

An Intermediary Role of Adenine Nucleotides on Free Fatty Acids-Induced Hyperglycemia in Obese Mice.

Increased plasma free fatty acids (FFA) level plays a central role in the development of type 2 diabetes. Our previous studies have shown that plasma 5′-adenosine monophosphate (5′-AMP) elevates and acts as a potential upstream regulator of hyperglycemia in diabetic db/db mice. The relationship between FFA and plasma adenosine nucleotides in type 2 diabetes remains unclear. Here we found that plasma 5′-AMP level was also increased in diabetic mice induced by a high-fat diet and streptozotocin (HFD-STZ), as observed in diabetic db/db mice. The metabolites of adenosine nucleotides in plasma were increased in obese mice compared to lean mice. An acute oil gavage to lean mice increased both FFA and plasma purine metabolites, accompanying with glucose intolerance. 5′-AMP administration resulted in an increase in dose-dependent purine metabolites and different levels of glucose intolerance. FFA induced a release of adenine nucleotides from cultural human umbilical vein endothelial cells (HUVECs) prior to induction of their apoptosis. FFA also reduced red blood cells (RBCs) resistance to reactive oxygen species (ROS), leading to hemolysis, thereby increasing plasma nucleotides. Our results suggest that plasma adenine nucleotides play an intermediary role in FFA-induced glucose intolerance and hyperglycemia in obese mice.

2472-PUB: JNK1 Plays a Causal Role in Palmitate-induced ß-Cell Dysfunction In Vivo

In obesity, chronically elevated circulating free fatty acids (FFA) potentially cause ß-cell dysfunction which leads to type 2 diabetes (T2D). In vitro data have identified various cellular mechanisms leading to FFA-induced ß-cell dysfunction including activation of inflammatory kinase c-Jun N-terminal kinase (JNK). In the ß-cell, JNK1 responds to oxidative stress or ER stress, which can both be caused by FFA. Previous in vitro studies from our group have demonstrated that islets of JNK1-null mice are protected from the effect of palmitate but not oleate on inducing ß-cell dysfunction, suggesting that activation of JNK1 is specific to saturated FFA. Thus, we hypothesized that saturated FFA-induced ß-cell dysfunction is mediated in part by JNK. Due to its detergent effects, palmitate cannot be infused directly into circulation. Thus, ethylpalmitate was used, as the ethyl group reduces the toxic effect. Mice can hydrolyze the ethyl group in circulation, producing palmitate and ethanol. JNK1-null (KO) mice and their littermate controls (WT) were infused with ethylpalmitate or ethanol vehicle for 48 hours, after which their pancreatic islets were isolated for ex vivo determination of insulin secretion. We confirmed that ethylpalmitate infusion does significantly increase plasma FFA as compared to vehicle infusion. We found that WT mice infused with ethylpalmitate demonstrated significantly decreased insulin secretion as compared with WT mice infused with vehicle, whereas JNK1-null mice infused with ethylpalmitate had similar insulin secretion as controls. These data suggest that JNK1 plays a causal role in saturated FFA-induced ß-cell dysfunction in vivo. Disclosure J. Yung: None. L. Yeung: None. A. Nahle: None. K. Koulajian: None. A. Giacca: Research Support; Self; Jazz Pharmaceuticals. Funding Canadian Institutes of Health Research