scholarly journals Impaired Hepatic Ketogenesis in Moderately Obese Men With Hypertriglyceridemia

2009 ◽  
Vol 57 (4) ◽  
pp. 590-594 ◽  
Author(s):  
Gloria Lena Vega ◽  
Fredrick L. Dunn ◽  
Scott M. Grundy
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
De Novo Lipogenesis ◽  
Nonesterified Fatty Acid ◽  
Acid Oxidation ◽  
Fasting State ◽  
Fatty Meal ◽  
Nonesterified Fatty Acids ◽  
Endogenous Hypertriglyceridemia

BackgroundSeveral studies suggest that increased nonesterified fatty acid flux and increased de novo lipogenesis may contribute to hypertriglyceridemia, but few studies have examined fatty acid oxidation as a factor.RationaleEndogenous hypertriglyceridemia (increased very low density lipoprotein triglyceride) could result from (a) re-esterification of excess nonesterified fatty acids entering the liver, (b) activation of hepatic lipogenesis, and/or (c) defective oxidation of hepatic fatty acids leading to greater triglyceride synthesis. Therefore, this study used plasma levels of 3-hydroxybutyrate as a marker for fatty acid oxidation. The study was carried out in hypertriglyceridemic and normotriglyceridemic subjects under 3 conditions: (a) in the fasting state, (b) after a fatty meal that should enhance fatty acid oxidation, and (c) after an oxandrolone challenge, which we recently showed increases fatty acid oxidation.ResultsIn the fasting state, 3-hydroxybutyrate concentrations in hypertriglyceridemic patients were only 53% of levels in normotriglyceridemic subjects. After a fatty meal, moderate increases in 3-hydroxybutyrate were observed, but values for patients with hypertriglceridemia remained 62% of the levels in the normotriglyceridemic group. A similar pattern of response was observed with oxandrolone challenge. There were no significant changes in fasting or postprandial levels of nonesterfified fatty acids, glycerol, or triglycerides before and during the oxandrolone challenge.ConclusionPatients with endogenous hypertriglyceridemia seem to have a defect in fatty acid oxidation as indicated by reduced levels of 3-hydroxybutyrate. This defect was observed during fasting, postprandially, and during oxandrolone challenge. We propose that this defect contributes to the development of hypertriglyceridemia.

Improved energy homeostasis of the heart in the metabolic state of exercise

2000 ◽  
Vol 279 (4) ◽  
pp. H1490-H1501 ◽  
Author(s):  
Gary W. Goodwin ◽  
Heinrich Taegtmeyer ◽  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Energy Homeostasis ◽  
Acid Oxidation ◽  
High Fat ◽  
Nonesterified Fatty Acids ◽  
Malonyl Coa ◽  
Metabolic Conditions ◽  
High Lactate

We postulate that metabolic conditions that develop systemically during exercise (high blood lactate and high nonesterified fatty acids) are favorable for energy homeostasis of the heart during contractile stimulation. We used working rat hearts perfused at physiological workload and levels of the major energy substrates and compared the metabolic and contractile responses to an acute low-to-high work transition under resting versus exercising systemic metabolic conditions (low vs. high lactate and nonesterified fatty acids in the perfusate). Glycogen preservation, resulting from better maintenance of high-energy phosphates, was a consequence of improved energy homeostasis with high fat and lactate. We explained the result by tighter coupling between workload and total β-oxidation. Total fatty acid oxidation with high fat and lactate reflected increased availability of exogenous and endogenous fats for respiration, as evidenced by increased long-chain fatty acyl-CoA esters (LCFA-CoAs) and by an increased contribution of triglycerides to total β-oxidation. Triglyceride turnover (synthesis and degradation) also appeared to increase. Elevated LCFA-CoAs caused high total β-oxidation despite increased malonyl-CoA. The resulting bottleneck at mitochondrial uptake of LCFA-CoAs stimulated triglyceride synthesis. Our results suggest the following. First, both malonyl-CoA and LCFA-CoAs determine total fatty acid oxidation in heart. Second, concomitant stimulation of peripheral glycolysis and lipolysis should improve cardiac energy homeostasis during exercise. We speculate that high lactate contributes to the salutary effect by bypassing the glycolytic block imposed by fatty acids, acting as an anaplerotic substrate necessary for high tricarbocylic acid cycle flux from fatty acid-derived acetyl-CoA.

scholarly journals Why does Brain Metabolism not Favor Burning of Fatty Acids to Provide Energy? - Reflections on Disadvantages of the Use of Free Fatty Acids as Fuel for Brain

2013 ◽  
Vol 33 (10) ◽  
pp. 1493-1499 ◽  
Author(s):  
Peter Schönfeld ◽  
Georg Reiser
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Brain Mitochondria ◽  
Neuronal Firing ◽  
Acid Oxidation ◽  
Nonesterified Fatty Acids ◽  
Atp Generation ◽  
Slow Passage ◽  
The Brain

It is puzzling that hydrogen-rich fatty acids are used only poorly as fuel in the brain. The long-standing belief that a slow passage of fatty acids across the blood–brain barrier might be the reason. However, this has been corrected by experimental results. Otherwise, accumulated nonesterified fatty acids or their activated derivatives could exert detrimental activities on mitochondria, which might trigger the mitochondrial route of apoptosis. Here, we draw attention to three particular problems: (1) ATP generation linked to β-oxidation of fatty acids demands more oxygen than glucose, thereby enhancing the risk for neurons to become hypoxic; (2) β-oxidation of fatty acids generates superoxide, which, taken together with the poor anti-oxidative defense in neurons, causes severe oxidative stress;(3) the rate of ATP generation based on adipose tissue-derived fatty acids is slower than that using blood glucose as fuel. Thus, in periods of extended continuous and rapid neuronal firing, fatty acid oxidation cannot guarantee rapid ATP generation in neurons. We conjecture that the disadvantages connected with using fatty acids as fuel have created evolutionary pressure on lowering the expression of the β-oxidation enzyme equipment in brain mitochondria to avoid extensive fatty acid oxidation and to favor glucose oxidation in brain.

Regulation of cardiac and skeletal muscle malonyl-CoA decarboxylase by fatty acids

2001 ◽  
Vol 280 (3) ◽  
pp. E471-E479 ◽  
Author(s):  
Martin E. Young ◽  
Gary W. Goodwin ◽  
Jun Ying ◽  
Patrick Guthrie ◽  
Christopher R. Wilson ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Fatty Acids ◽  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Rat Heart ◽  
Acid Oxidation ◽  
High Fat ◽  
Nonesterified Fatty Acids ◽  
Malonyl Coa ◽  
Fat Feeding

Malonyl-CoA decarboxylase (MCD) catalyzes the degradation of malonyl-CoA, an important modulator of fatty acid oxidation. We hypothesized that increased fatty acid availability would increase the expression and activity of heart and skeletal muscle MCD, thereby promoting fatty acid utilization. The results show that high-fat feeding, fasting, and streptozotocin-induced diabetes all significantly increased the plasma concentration of nonesterified fatty acids, with a concomitant increase in both rat heart and skeletal muscle MCD mRNA. Upon refeeding of fasted animals, MCD expression returned to basal levels. Fatty acids are known to activate peroxisome proliferator-activated receptor-α (PPARα). Specific PPARα stimulation, through Wy-14643 treatment, significantly increased the expression of MCD in heart and skeletal muscle. Troglitazone, a specific PPARγ agonist, decreased MCD expression. The sensitivity of MCD induction by fatty acids and Wy-14643 was soleus > extensor digitorum longus > heart. High plasma fatty acids consistently increased MCD activity only in solei, whereas MCD activity in the heart actually decreased with high-fat feeding. Pressure overload-induced cardiac hypertrophy, in which PPARα expression is decreased (and fatty acid oxidation is decreased), resulted in decreased MCD mRNA and activity, an effect that was dependent on fatty acids. The results suggest that fatty acids induce the expression of MCD in rat heart and skeletal muscle. Additional posttranscriptional mechanisms regulating MCD activity appear to exist.

scholarly journals Progesterone receptor membrane component 1 reduces cardiac steatosis and lipotoxicity via activation of fatty acid oxidation and mitochondrial respiration

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sang R. Lee ◽  
Jun H. Heo ◽  
Seong Lae Jo ◽  
Globinna Kim ◽  
Su Jung Kim ◽  
...  
Keyword(s):  
Heart Failure ◽  
Fatty Acid ◽  
Progesterone Receptor ◽  
Fatty Acid Oxidation ◽  
Mitochondrial Respiration ◽  
De Novo Lipogenesis ◽  
Acid Oxidation ◽  
Membrane Component ◽  
Markers Of Inflammation ◽  
Receptor Membrane

AbstractObesity is implicated in cardiovascular disease and heart failure. When fatty acids are transported to and not adequately oxidized in cardiac cells, they accumulate, causing lipotoxicity in the heart. Since hepatic progesterone receptor membrane component 1 (Pgrmc1) suppressed de novo lipogenesis in a previous study, it was questioned whether cardiac Pgrmc1 protects against lipotoxicity. Hence, we focused on the role of cardiac Pgrmc1 in basal (Resting), glucose-dominant (Refed) and lipid-dominant high-fat diet (HFD) conditions. Pgrmc1 KO mice showed high FFA levels and low glucose levels compared to wild-type (WT) mice. Pgrmc1 KO mice presented low number of mitochondrial DNA copies in heart, and it was concomitantly observed with low expression of TCA cycle genes and oxidative phosphorylation genes. Pgrmc1 absence in heart presented low fatty acid oxidation activity in all conditions, but the production of acetyl-CoA and ATP was in pronounced suppression only in HFD condition. Furthermore, HFD Pgrmc1 KO mice resulted in high cardiac fatty acyl-CoA levels and TG level. Accordingly, HFD Pgrmc1 KO mice were prone to cardiac lipotoxicity, featuring high levels in markers of inflammation, endoplasmic reticulum stress, oxidative stress, fibrosis, and heart failure. In vitro study, it was also confirmed that Pgrmc1 enhances rates of mitochondrial respiration and fatty acid oxidation. This study is clinically important because mitochondrial defects in Pgrmc1 KO mice hearts represent the late phase of cardiac failure.

scholarly journals Mitochondrial Fission Governed by Drp1 Regulates Exogenous Fatty Acid Usage and Storage in Hela Cells

Metabolites ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 322
Author(s):  
Jae-Eun Song ◽  
Tiago C. Alves ◽  
Bernardo Stutz ◽  
Matija Šestan-Peša ◽  
Nicole Kilian ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Lipid Droplets ◽  
Mitochondrial Fission ◽  
Acid Oxidation ◽  
Mitochondrial Morphology ◽  
Mitochondrial Fatty Acid Oxidation ◽  
Mitochondrial Fatty Acid ◽  
And Storage

In the presence of high abundance of exogenous fatty acids, cells either store fatty acids in lipid droplets or oxidize them in mitochondria. In this study, we aimed to explore a novel and direct role of mitochondrial fission in lipid homeostasis in HeLa cells. We observed the association between mitochondrial morphology and lipid droplet accumulation in response to high exogenous fatty acids. We inhibited mitochondrial fission by silencing dynamin-related protein 1(DRP1) and observed the shift in fatty acid storage-usage balance. Inhibition of mitochondrial fission resulted in an increase in fatty acid content of lipid droplets and a decrease in mitochondrial fatty acid oxidation. Next, we overexpressed carnitine palmitoyltransferase-1 (CPT1), a key mitochondrial protein in fatty acid oxidation, to further examine the relationship between mitochondrial fatty acid usage and mitochondrial morphology. Mitochondrial fission plays a role in distributing exogenous fatty acids. CPT1A controlled the respiratory rate of mitochondrial fatty acid oxidation but did not cause a shift in the distribution of fatty acids between mitochondria and lipid droplets. Our data reveals a novel function for mitochondrial fission in balancing exogenous fatty acids between usage and storage, assigning a role for mitochondrial dynamics in control of intracellular fuel utilization and partitioning.

Meal composition affects postprandial fatty acid oxidation

1993 ◽  
Vol 264 (6) ◽  
pp. R1065-R1070 ◽  
Author(s):  
D. M. Surina ◽  
W. Langhans ◽  
R. Pauli ◽  
C. Wenk
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Nutrient Utilization ◽  
Whole Body ◽  
Acid Oxidation ◽  
Plasma Ffa ◽  
Hepatic Fatty Acid Oxidation ◽  
Beta Hydroxybutyrate ◽  
Chain Fatty Acids

The influence of macronutrient content of a meal on postprandial fatty acid oxidation was investigated in 13 Caucasian males after consumption of a high-fat (HF) breakfast (33% carbohydrate, 52% fat, 15% protein) and after an equicaloric high-carbohydrate (HC) breakfast (78% carbohydrate, 6% fat, 15% protein). The HF breakfast contained short- and medium-chain fatty acids, as well as long-chain fatty acids. Respiratory quotient (RQ) and plasma beta-hydroxybutyrate (BHB) were measured during the 3 h after the meal as indicators of whole body substrate oxidation and hepatic fatty acid oxidation, respectively. Plasma levels of free fatty acids (FFA), triglycerides, glucose, insulin, and lactate were also determined because of their relationship to nutrient utilization. RQ was significantly lower and plasma BHB was higher after the HF breakfast than after the HC breakfast, implying that more fat is burned in general and specifically in the liver after an HF meal. As expected, plasma FFA and triglycerides were higher after the HF meal, and insulin and lactate were higher after the HC meal. In sum, oxidation of ingested fat occurred in response to a single HF meal.

scholarly journals EFFECTS OF CORTISOL ON CULTURED RAT HEART CELLS

1973 ◽  
Vol 57 (1) ◽  
pp. 109-116 ◽  
Author(s):  
J. V. Anastasia ◽  
R. L. McCarl
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Free Fatty Acids ◽  
Fatty Acid Oxidation ◽  
Growth Medium ◽  
Rat Heart ◽  
Acid Oxidation ◽  
Heart Cells ◽  
Atp Production ◽  
Rat Heart Cells

This paper reports the determination of the ability of rat heart cells in culture to release [14C]palmitate from its triglyceride and to oxidize this fatty acid and free [14C]palmitate to 14CO2 when the cells are actively beating and when they stop beating after aging in culture. In addition, the levels of glucose, glycogen, and ATP were determined to relate the concentration of these metabolites with beating and with cessation of beating. When young rat heart cells in culture are actively beating, they oxidize free fatty acids at a rate parallel with cellular ATP production. Both fatty acid oxidation and ATP production remain constant while the cells continue to beat. Furthermore, glucose is removed from the growth medium by the cells and stored as glycogen. When cultured cells stop beating, a decrease is seen in their ability to oxidize free fatty acids and to release them from their corresponding triglycerides. Concomitant with decreased fatty acid oxidation is a decrease in cellular levels of ATP until beating ceases. Midway between initiation of cultures and cessation of beating the cells begin to mobilize the stored glycogen. When the growth medium is supplemented with cortisol acetate and given to cultures which have ceased to beat, reinitiation of beating occurs. Furthermore, all decreases previously observed in ATP levels, fatty acid oxidation, and esterase activity are restored.

Abstract 653: Muscle Ring Finger-1 (MuRF1) Expression Shifts Cardiomyocyte Substrate Utilization from Fatty Acids to Glucose

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Monte S Willis ◽  
Jon Schisler ◽  
Holly McDonough ◽  
Cam Patterson
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Glucose Oxidation ◽  
Relative Proportion ◽  
Substrate Utilization ◽  
Acid Oxidation ◽  
Protective Mechanism ◽  
Dependent Manner ◽  
Dose Dependent

Previous work has suggested that MuRF1, a cardiac-specific protein, regulates metabolism by its interactions with proteins that regulate ATP transport, glycolysis, and the electron transport chain. We recently identified that MuRF1 is cardioprotective in ischemia reperfusion injury. In the current study, we investigated the effects of MuRF1 expression on metabolic substrate utilization and found that MuRF1 shifts substrate utilization from fatty acids to glucose in a dose-dependent manner. Isolated neonatal ventricular cardiomyocytes were treated with an adenovirus expressing MuRF1 (Ad.MuRF1) or GFP (Ad.GFP) at a range of 0–25 MOI (Multiplicity Of Infection). 14C-Oleate or 14C-glucose were added to cells for 1 hour and 14C-CO2 release was determined using the CO2-trapping method. Trapped 14CO2 and acid soluble metabolites were used to calculate total fatty acid oxidation. Cardiomyocytes treated with 5–25 MOI Ad.MuRF1 demonstrated a dose dependent decrease in fatty acid oxidation of 10.5 +/− 2.3(5 MOI), 8.5 +/− 1.9 (10 MOI), 6.6 +/− 1.6 (15 MOI), and 5.1 +/− 1.3 (25 MOI) nmol oleate/mg protein/h. Compared with control cardiomyocytes treated with 5–25 MOI Ad.GFP (average of 5–25 MOI=13.5 +/− 0.7 nmol oleate/mg protein/h), this represents a 22.2%– 62.2% decrease in fatty acid oxidation. Inversely, glucose oxidation increased with increasing MuRF1 expression. Cardiomyocytes infected with 25 MOI Ad.MuRF1 oxidized 184% more glucose (28.9 +/− 4.6 nmol glucose/mg protein/h) compared to control cells treated with 25 MOI Ad.GFP (15.7 +/− 1.3 nmol glucose/mg protein/h). Increasing MuRF1 expression resulted in no net gain or loss of calculated ATP production (1699 +/− 157 vs. 1480 +/− 188 nmol ATP/mg protein/h). The co-utilization of glucose and fatty acids as substrates for the production of ATP allows the heart to adapt to both environmental stress and disease. Increasing the relative proportion of glucose oxidation in relationship to fatty acids is a known protective mechanism during cardiac stress, and may represent one mechanism by which MuRF1 is cardioprotective.

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