Successful management of rhabdomyolysis with triheptanoin in a child with severe long-chain 3-hydroxyacyl-coenzyme A dehydrogenase (LCHAD) deficiency.

Early-onset long-chain 3-hydroxyacyl-coenzyme A dehydrogenase (LCHAD) deficiency is a fatty acid ß-oxidation disorder with a poor prognosis. Triheptanoin, an anaplerotic oil with odd-chain fatty acids can improve the disease course. The female patient presented here was diagnosed at the age of 4 months, and treatment was started as fat restriction, frequent feeding, and standard medium-chain triglyceride supplementation. In follow-up, she had frequent rhabdomyolysis episodes (∼8 per year). At the age of six, she had 13 episodes in 6 months, and triheptanoin was started as part of a compassionate use program. Following unrelated hospital stays due to multisystem inflammatory syndrome in children and a bloodstream infection, she had only 3 rhabdomyolysis episodes, and hospitalized days decreased from 73 to 11 during her first year with triheptanoin. Triheptanoin drastically decreased the frequency and severity of rhabdomyolysis, but progression of retinopathy was not altered.

Increase in omega-6 and decrease in omega-3 polyunsaturated fatty acid oxidation elevates the risk of exudative AMD development in adults with Chinese diet.

Appropriate diet is essential for the regulation of age-related macular degeneration (AMD). In particular the type of dietary polyunsaturated fatty acids (PUFA) and poor antioxidant status including carotenoid levels concomitantly contribute to AMD risk. Build-up of oxidative stress in AMD induces PUFA oxidation, and a mix of lipid oxidation products (LOPs) are generated. However, LOPs are not comprehensively evaluated in AMD. LOPs are considered biomarkers of oxidative stress but also contributes to inflammatory response. In this cross-sectional case-control study, plasma omega-6/omega-3 PUFA ratios and antioxidant status (glutathione, superoxide dismutase and catalase), and plasma and urinary LOPs (41 types) were determined to evaluate its odds-ratio in the risk of developing exudative AMD (n = 99) compared to age-gender-matched healthy controls (n = 198) in adults with Chinese diet. The odds ratio of developing exudative AMD increased with LOPs from omega-6 PUFA and decreased from those of omega-3 PUFA. These observations were associated with a high plasma omega-6/omega-3 PUFA ratio and low carotenoid levels. In short, poor PUFA and antioxidant status increased the production of omega-6 PUFA LOPs such as dihomo-isoprostane and dihomo-isofuran, and lowered omega-3 PUFA LOPs such as neuroprostanes due to the high omega-6/omega-3 PUFA ratios; they were also correlated to the risk of AMD development. These findings indicate the generation of specific LOPs is associated with the development of exudative AMD.

Activation of SIRT1 by L-serine increases fatty acid oxidation and reverses insulin resistance in C2C12 myotubes.

Silent information regulator 1 (SIRT1) is a nicotinamide adenine dinucleotide (NAD+)-dependent deacetylase, and the function is linked to cellular metabolism including mitochondrial biogenesis. Hepatic L-serine concentration is decreased significantly in fatty liver disease. We reported that the supplementation of the amino acid ameliorated the alcoholic fatty liver by enhancing L-serine-dependent homocysteine metabolism. In this study, we hypothesized that the metabolic production of NAD+ from L-serine and thus activation of SIRT1 contribute to the action of L-serine. To this end, we evaluated the effects of L-serine on SIRT1 activity and mitochondria biogenesis in C2C12 myotubes. L-Serine increased intracellular NAD+ content and led to the activation of SIRT1 as determined by p53 luciferase assay and western blot analysis of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) acetylation. L-Serine treatment increased the expression of the genes associated with mitochondrial biogenesis and enhanced mitochondrial mass and function. In addition, L-serine reversed cellular insulin resistance determined by insulin-induced phosphorylation of Akt and GLUT4 expression and membrane translocation. L-Serine-induced mitochondrial gene expression, fatty acid oxidation, and insulin sensitization were mediated by enhanced SIRT1 activity, which was verified by selective SIRT1 inhibitor (Ex-527) and siRNA directed to SIRT1. L-Serine effect on cellular NAD+ level is dependent on the L-serine metabolism to pyruvate that is subsequently converted to lactate by lactate dehydrogenase. In summary, these data suggest that L-serine increases cellular NAD+ level and thus SIRT1 activity in C2C12 myotubes.

Two NADH-dependent (S)-3-hydroxyacyl-CoA dehydrogenases from polyhydroxyalkanoate-producing Ralstonia eutropha.

Ralstonia eutropha H16 contains both NADH- and NADPH-dependent reduction activities to acetoacetyl-CoA, and the NADPH-dependent activity is mediated by PhaB paralogs with (R)-stereospecificity providing (R)-3-hydroxybutyryl (3HB)-CoA monomer for poly((R)-3-hydroxybutyrate) synthesis. In contrast, the gene encoding the NADH-dependent enzyme has not been identified to date. This study focused on the NADH-dependent dehydrogenase with (S)-stereospecificity in R. eutropha, as the (S)-specific reduction of acetoacetyl-CoA potentially competed with the polyester biosynthesis via (R)-3HB-CoA. The NADH-dependent reduction activity decreased to one-half when the gene for H16_A0282 (PaaH1), one of two homologs of clostridial NADH-3HB-CoA dehydrogenase, was deleted. The enzyme responsible for the remaining activity was partially purified and identified as H16_A0602 (Had) belonging to a different family from PaaH1. Gene disruption analysis elucidated that most of the NADH-dependent activity was mediated by PaaH1 and Had. The kinetic analysis using the recombinant enzymes indicated that PaaH1 and Had were both NADH-dependent 3-hydroxyacyl-CoA dehydrogenases with rather broad substrate specificity to 3-oxoacyl-CoAs of C4 to C8. The deletion of had in the R. eutropha strain previously engineered for biosynthesis of poly((R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoate) led to decrease in the C6 composition of the copolyester synthesized from soybean oil, suggesting the role of Had in (S)-specific reduction of 3-oxohexanoyl-CoA with reverse ß-oxidation direction. Crotonase ((S)-specific enoyl-CoA hydratase) in R. eutropha H16 was also partially purified and identified as H16_A3307.

A 9-wk docosahexaenoic acid-enriched supplementation improves endurance exercise capacity and skeletal muscle mitochondrial function in adult rats.

Decline in skeletal muscle mass and function starts during adulthood. Among the causes, modifications of the mitochondrial function could be of major importance. Polyunsaturated fatty (ω-3) acids have been shown to play a role in intracellular functions. We hypothesize that docosahexaenoic acid (DHA) supplementation could improve muscle mitochondrial function that could contribute to limit the early consequences of aging on adult muscle. Twelve-month-old male Wistar rats were fed a low-polyunsaturated fat diet and were given DHA (DHA group) or placebo (control group) for 9 wk. Rats from the DHA group showed a higher endurance capacity (+56%, P < 0.05) compared with control animals. Permeabilized myofibers from soleus muscle showed higher O2 consumptions (P < 0.05) in the DHA group compared with the control group, with glutamate-malate as substrates, both in basal conditions (i.e., state 2) and under maximal conditions (i.e., state 3, using ADP), along with a higher apparent Km for ADP (P < 0.05). Calcium retention capacity of isolated mitochondria was lower in DHA group compared with the control group (P < 0.05). Phospho-AMPK/AMPK ratio and PPARδ mRNA content were higher in the DHA group compared with the control group (P < 0.05). Results showed that DHA enhanced endurance capacity in adult animals, a beneficial effect potentially resulting from improvement in mitochondrial function, as suggested by our results on permeabilized fibers. DHA supplementation could be of potential interest for the muscle function in adults and for fighting the decline in exercise tolerance with age that could imply energy-sensing pathway, as suggested by changes in phospho-AMPK/AMPK ratio.

Mitochondrial bioenergetics deregulation caused by long-chain 3-hydroxy fatty acids accumulating in LCHAD and MTP deficiencies in rat brain: a possible role of mPTP opening as a pathomechanism in these disorders?

Long-chain 3-hydroxylated fatty acids (LCHFA) accumulate in long-chain 3-hydroxy-acyl-CoA dehydrogenase (LCHAD) and mitochondrial trifunctional protein (MTP) deficiencies. Affected patients usually present severe neonatal symptoms involving cardiac and hepatic functions, although long-term neurological abnormalities are also commonly observed. Since the underlying mechanisms of brain damage are practically unknown and have not been properly investigated, we studied the effects of LCHFA on important parameters of mitochondrial homeostasis in isolated mitochondria from cerebral cortex of developing rats. 3-Hydroxytetradecanoic acid (3 HTA) reduced mitochondrial membrane potential, NAD(P)H levels, Ca(2+) retention capacity and ATP content, besides inducing swelling, cytochrome c release and H2O2 production in Ca(2+)-loaded mitochondrial preparations. We also found that cyclosporine A plus ADP, as well as ruthenium red, a Ca(2+) uptake blocker, prevented these effects, suggesting the involvement of the mitochondrial permeability transition pore (mPTP) and an important role for Ca(2+), respectively. 3-Hydroxydodecanoic and 3-hydroxypalmitic acids, that also accumulate in LCHAD and MTP deficiencies, similarly induced mitochondrial swelling and decreased ATP content, but to a variable degree pending on the size of their carbon chain. It is proposed that mPTP opening induced by LCHFA disrupts brain bioenergetics and may contribute at least partly to explain the neurologic dysfunction observed in patients affected by LCHAD and MTP deficiencies.

Dietary L-arginine supplementation reduces abdominal fat content by modulating lipid metabolism in broiler chickens.

This study investigated the effects of different levels of dietary L-arginine (L-Arg) supplementation on the abdominal fat pad, circulating lipids, hepatic fatty acid synthase (FAS) gene expression, gene expression related to fatty acid ß-oxidation, and the performance of broiler chickens. We tested whether the dietary L-Arg levels affected the expression of genes related to lipid metabolism in order to reduce body fat deposition. A total of 192 broiler chickens (Cobb 500) aged 21 days with an average BW of 920 ± 15 g were randomly assigned to four groups (six broilers per replicate and eight replicates per treatment). The control group was fed a basal diet, whereas the treatment groups were fed basal diets supplemented with 0.25%, 0.50%, or 1.00% L-Arg for 3 weeks. The average daily feed intake, average daily gain and feed : gain ratio were not affected by the dietary L-Arg levels. However, chickens supplemented with L-Arg had lower abdominal fat content, plasma triglyceride (TG), total cholesterol (TC) concentrations, hepatic FAS mRNA expression and increased heart carnitine palmitoyl transferase1 (CPT1) and 3-hydroxyacyl-CoA dehydrogenase (3HADH) mRNA expression. These findings suggest that the addition of 0.25% L-Arg may reduce the plasma TC concentration by decreasing hepatic 3-hydroxyl-3-methylglutaryl-CoA reductase mRNA expression. This may lower the plasma TG and abdominal fat content by suppressing hepatic FAS mRNA expression and enhancing CPT1 and 3HADH (genes related to fatty acid ß-oxidation) mRNA expression in the hearts of broiler chickens.

[Effects of acupuncture and moxibustion on energy metabolism-related protein of hippocampal neuron mitochondria in Alzheimer's disease rats].

OBJECTIVE: To explore action mechanism of acupuncture and moxibustion for Alzheimer's disease (AD) to provide evidence for prevention and treatment with acupuncture and moxibustion on AD in clinic. METHODS: Eighty SPF-grade male Wistar rats, (200 +/- 20) g, were randomly divided into a normal group, a sham-operation group, a model group and a treatment group, 20 cases in each one. The model was duplicated with injection of Abeta1-42 in rats' hippocampus. Expect the treatment group, the rest groups were treated with regular feeding after respective intervention. The treatment group was treated with acupuncture and moxibustion at "Baihui" (GV 20) and "Shenshu" (BL 23), once a day, seven days as a treatment course and totally for two courses. There was one day of interval between the courses. The immunohistochemistry and quantitative RT-PCR methods were applied to test level of Abeta-binding alcohol dehydrogense (ABAD) and cytochrome oxidase IV (COX IV) in hippocampal neurons mitochondria. RESULTS: Acupuncture and moxibustion could reduce effectively level of ABAD and improve activity of COX IV in hippocampal neurons mitochondria in the treatment group, which has statistical significance compared with that in the model group (P < 0.01) and no statistical significance compared with that in the normal group and sham-operation group (P > 0.05). This indicated that acupuncture and moxibustion could effectively suppress overexpression of ABAD, improve activity of COX IV and reduce leak of reactive oxygen species, which could improve metabolic disturbance of mitochondria energy to achieve the goal of prevention and treatment of AD. CONCLUSION: The prevention and treatment of AD with acupuncture and moxibustion could be related with suppressing overexpression of ABAD and improving activity of COX IV in hippocampal neurons mitochondria to improve mitochondria energy metabolism.

Garlic provides protection to mice heart against isoproterenol-induced oxidative damage: role of nitric oxide.

Garlic has been widely recognized as a cardioprotective agent. However, the molecular mechanism of its cardioprotective effects is not well established. Here we hypothesized that aqueous garlic homogenate may mediate cardioprotection via nitric oxide (NO). Mice were fed with saline and aqueous garlic homogenate (250 and 500 mgkg(-1)day(-1) orally) for 30 days. In another set of experiment, mice were pre-treated with saline, aqueous garlic homogenate (AGH) (250 mgkg(-1)day(-1) for 30 days), and AGH (30 days) along with L-NAME (20 mgkg(-1)day(-1) i.p. for last 7 days) before inducing acute myocardial infarction by isoproterenol (s.c. injection of isoproterenol 150 mgkg(-1)day(-1) for 2 days) and sacrificed after 48 h. Dose dependent increase in serum NO level was observed after garlic 250 and 500 mgkg(-1) dose feeding. While no change in serum SGPT and SGOT level, a significant decrease in serum LDH level was observed after garlic feeding. Garlic-induced NO formation was further confirmed in human aortic endothelial cells (HAEC). Administration of isoproterenol caused a significant decrease in endogenous antioxidants i.e., myocardial catalase, GSH and GPx activity, and mitochondrial enzyme activities like citrate synthase and ß hydroxyacyl CoA dehydrogenase. All those deleterious cardiac changes induced by isoproterenol were significantly attenuated by garlic homogenate. However this beneficial effect of garlic was blunted when garlic was administered with L-NAME, a nonspecific inhibitor of nitric oxide synthase (NOS). Further, a significant increase in myocardial TBARS and decrease in total antioxidant activity was observed in L-NAME treated group compared to isoproterenol treated group. Administration of L-NAME in mice from control group lowered serum and cardiac NO levels without any change of oxidative stress parameters. In conclusion, our study provides novel evidence that garlic homogenate is protective in myocardial infarction via NO-signaling pathway in mice.

Ovarian hormone loss induces bioenergetic deficits and mitochondrial ß-amyloid.

Previously, we demonstrated that reproductive senescence was associated with mitochondrial deficits comparable to those of female triple-transgenic Alzheimer's mice (3xTgAD). Herein, we investigated the impact of chronic ovarian hormone deprivation and 17ß-estradiol (E2) replacement on mitochondrial function in nontransgenic (nonTg) and 3xTgAD female mouse brain. Depletion of ovarian hormones by ovariectomy (OVX) in nontransgenic mice significantly decreased brain bioenergetics, and induced mitochondrial dysfunction and oxidative stress. In 3xTgAD mice, OVX significantly exacerbated mitochondrial dysfunction and induced mitochondrial ß-amyloid and ß-amyloid (Aß)-binding-alcohol-dehydrogenase (ABAD) expression. Treatment with E2 at OVX prevented OVX-induced mitochondrial deficits, sustained mitochondrial bioenergetic function, decreased oxidative stress, and prevented mitochondrial ß-amyloid and ABAD accumulation. In vitro, E2 increased maximal mitochondrial respiration in neurons and basal and maximal respiration in glia. Collectively, these data demonstrate that ovarian hormone loss induced a mitochondrial phenotype comparable to a transgenic female model of Alzheimer's disease (AD), which was prevented by E2. These findings provide a plausible mechanism for increased risk of Alzheimer's disease in premenopausally oophorectomized women while also suggesting a therapeutic strategy for prevention.

Swimming performance and energy homeostasis in juvenile laboratory raised fathead minnow (Pimephales promelas) exposed to uranium mill effluent.

Research at the Key Lake uranium mill (Saskatchewan, Canada) suggests effluent discharged from the mill affects energy stores of resident fish, but the mechanisms by which energy homeostasis is affected and the subsequent effects on swimming performance are unknown. In the present study larvae were collected from laboratory raised adult fathead minnow (Pimephales promelas) exposed to 5% diluted uranium mill effluent or control (dechlorinated municipal) water, and reared in the same treatments to 60 days post hatch (dph). Critical swimming speed (U(crit)) was significantly lower in effluent exposed 60 dph fish compared to control fish. Fish used in tests were considered fatigued and compared to fish without swim testing (non-fatigued). There were no differences in whole body glycogen or triglyceride concentrations between effluent exposed versus control fish. However, fatigued fish from both treatments had significantly lower triglycerides, but not glycogen, compared to non-fatigued fish from the same treatment. Whole body ß-hydroxyacyl coenzymeA dehydrogenase activity was similar in fish from both treatments, but citrate synthase activity was significantly lower in effluent exposed fish. Our results suggest uranium mill effluent exposure in the laboratory affects aerobic energy metabolism and swimming performance in juvenile fathead minnow, which could affect wild fish survivability.

Mitochondrial ß-amyloid in Alzheimer's disease.

It is well established that the intracellular accumulation of Aß (amyloid ß-peptide) is associated with AD (Alzheimer's disease) and that this accumulation is toxic to neurons. The precise mechanism by which this toxicity occurs is not well understood; however, identifying the causes of this toxicity is an essential step towards developing treatments for AD. One intracellular location where the accumulation of Aß can have a major effect is within mitochondria, where mitochondrial proteins have been identified that act as binding sites for Aß, and when binding occurs, a toxic response results. At one of these identified sites, an enzyme known as ABAD (amyloid-binding alcohol dehydrogenase), we have identified changes in gene expression in the brain cortex, following Aß accumulation within mitochondria. Specifically, we have identified two proteins that are up-regulated not only in the brains of transgenic animal models of AD but also in those of human sufferers. The increased expression of these proteins demonstrates the complex and counteracting pathways that are activated in AD. Previous studies have identified approximate contact sites between ABAD and Aß; on basis of these observations, we have shown that by using a modified peptide approach it is possible to reverse the expression of these two proteins in living transgenic animals and also to recover mitochondrial and behavioural deficits. This indicates that the ABAD-Aß interaction is potentially an interesting target for therapeutic intervention. To explore this further we used a fluorescing substrate mimic to measure the activity of ABAD within living cells, and in addition we have identified chemical fragments that bind to ABAD, using a thermal shift assay.

Effects of olive oil and its minor phenolic constituents on obesity-induced cardiac metabolic changes.

BACKGROUND: Olive oil and its minor constituents have been recommended as important dietary therapeutic interventions in preventive medicine. However, a question remains to be addressed: what are the effects of olive oil and its phenolic compounds on obesity-induced cardiac metabolic changes? METHODS: Male Wistar rats were divided into two groups (n = 24/group): (C) receiving standard-chow; (Ob) receiving hypercaloric-chow. After 21 days C and Ob groups were divided into four subgroups (n = 6/group):(C) standard-chow and saline; (C-Olive)standard-chow and olive-oil (3.0 g/kg.day); (C-Oleuropein)standard-chow and oleuropein (0.023 mg/kg/day); (C-Cafeic) standard-chow and cafeic-acid (2.66 mg/kg/day); (Ob)receiving hypercaloric-chow and saline;(Ob-Olive) hypercaloric-chow and olive-oil;(Ob-Oleuropein) hypercaloric-chow and oleuropein;(Ob-Cafeic) hypercaloric-chow and cafeic-acid. Treatments were given twice a week during 21 days. RESULTS: After 42 days, obesity was evidenced in Ob rats from enhanced body-weight, surface-area, and body-mass-index. Energy-expenditure, oxygen consumption(VO2) and fat-oxidation were lower in Ob-group than in C. Despite no morphometric changes, Ob-Olive, Ob-Oleuropein and Ob-Cafeic groups had higher VO2, fat-oxidation, myocardial beta-hydroxyacyl coenzyme-A dehydrogenase and lower respiratory-quotient than Ob. Citrate-synthase was highest in Ob-Olive group. Myocardial lipid-hydroperoxide(LH) and antioxidant enzymes were unaffected by olive-oil and its compounds in obesity condition, whereas LH was lower and total-antioxidant-substances were higher in C-Olive and C-Oleuropein than in C. CONCLUSIONS: The present study demonstrated for the first time that olive-oil, oleuropein and cafeic-acid enhanced fat-oxidation and optimized cardiac energy metabolism in obesity conditions. Olive oil and its phenolic compounds improved myocardial oxidative stress in standard-fed conditions.

Endurance capacity in maturing mdx mice is markedly enhanced by combined voluntary wheel running and green tea extract.

Duchenne muscular dystrophy is characterized by the absence of dystrophin from muscle cells. Dystrophic muscle cells are susceptible to oxidative stress. We tested the hypothesis that 3 wk of endurance exercise starting at age 21 days in young male mdx mice would blunt oxidative stress and improve dystrophic skeletal muscle function, and these effects would be enhanced by the antioxidant green tea extract (GTE). In mice fed normal diet, average daily running distance increased 300% from week 1 to week 3, and total distance over 3 wk was improved by 128% in mice fed GTE. Running, independent of diet, increased serum antioxidant capacity, extensor digitorum longus tetanic stress, and total contractile protein content, heart citrate synthase, and heart and quadriceps beta-hydroxyacyl-CoA dehydrogenase activities. GTE, independent of running, decreased serum creatine kinase and heart and gastrocnemius lipid peroxidation and increased gastrocnemius citrate synthase activity. These data suggest that both endurance exercise and GTE may be beneficial as therapeutic strategies to improve muscle function in mdx mice.

Conjugated linoleic acid and cardiac health: oxidative stress and energetic metabolism in standard and sucrose-rich diets.

Studies on conjugated linoleic acid ingestion and its effect on cardiac tissue are necessary for the safe utilization of this compound as supplement for weight loss. Male Wistar 24-rats were divided into four groups (n=6):(C)given standard chow, water and 0.5 ml saline, twice a week by gavage; (C-CLA)receiving standard chow, water and 0.5 ml of conjugated linoleic acid, twice a week, by gavage; (S)given standard chow, saline by gavage, and 30% sucrose in its drinking water; (S-CLA)receiving standard chow, 30% sucrose in its drinking water and conjugated linoleic acid. After 42 days of treatment S rats had obesity with increased abdominal-circumference, dyslipidemia, oxidative stress and myocardial lower citrate synthase(CS) and higher lactate dehydrogenase(LDH) activities than C. Conjugated linoleic acid had no effects on morphometric parameters in C-CLA, as compared to C, but normalized morphometric parameters comparing S-CLA with S. There was a negative correlation between abdominal adiposity and resting metabolic rate. Conjugated linoleic acid effect, enhancing fasting-VO(2)/surface area, postprandial-carbohydrate oxidation and serum lipid hydroperoxide resembled to that of the S group. Conjugated linoleic acid induced cardiac oxidative stress in both fed conditions, and triacylglycerol accumulation in S-CLA rats. Conjugated linoleic acid depressed myocardial LDH comparing C-CLA with C, and beta-hydroxyacyl-coenzyme-A dehydrogenase/CS ratio, comparing S-CLA with S. In conclusion, dietary conjugated linoleic acid supplementation for weight loss can have long-term effects on cardiac health. Conjugated linoleic acid, isomers c9, t11 and t10, c12c9,t11" and "t10,c12" were changed to "c9, t11" and "t10, c12", respectively. Please check if appropriate.--> presented undesirable pro-oxidant effect and induced metabolic changes in cardiac tissue. Nevertheless, despite its effect on abdominal adiposity in sucrose-rich diet condition, conjugated linoleic acid may be disadvantageous because it can lead to oxidative stress and dyslipidemic profile.

The pesticide adjuvant, Toximul, alters hepatic metabolism through effects on downstream targets of PPARalpha.

Previous studies demonstrated that chronic dermal exposure to the pesticide adjuvant (surfactant), Toximul (Tox), has significant detrimental effects on hepatic lipid metabolism. This study demonstrated that young mice dermally exposed to Tox for 12 days have significant increases in expression of peroxisomal acyl-CoA oxidase (mRNA and protein), bifunctional enzyme (mRNA) and thiolase (mRNA), as well as the P450 oxidizing enzymes Cyp4A10 and Cyp4A14 (mRNA and protein). Tox produced a similar pattern of increases in wild type adult female mice but did not induce these responses in PPARalpha-null mice. These data support the hypothesis that Tox, a heterogeneous blend of nonionic and anionic surfactants, modulates hepatic metabolism at least in part through activation of PPARalpha. Notably, all three groups of Tox-treated mice had increased relative liver weights due to significant accumulation of lipid. This could be endogenous in nature and/or a component(s) of Tox or a metabolite thereof. The ability of Tox and other hydrocarbon pollutants to induce fatty liver despite being PPARalpha agonists indicates a novel consequence of exposure to this class of chemicals, and may provide a new understanding of fatty liver in populations with industrial exposure.

Effect of L-carnitine supplementation and aerobic training on FABPc content and beta-HAD activity in human skeletal muscle.

Both regular physical exercise and carnitine supplementation exert a role in energy metabolism and may improve endurance capacity. We investigated whether a combination of long-term carnitine ingestion and exercise training reveals any interactive effects on cytosolic fatty acid-binding protein (FABPc) expression and beta-hydroxyacyl CoA dehydrogenase (beta-HAD) activity in human skeletal muscle. Twenty-eight untrained healthy males randomly divided into four experimental groups: a placebo (CON; n = 7), exercise training (ET; n = 7, 40 min session(-1), five times per week at 60% VO2max), carnitine supplementation (CS; n = 7, 4 g day(-1)), and exercise training and carnitine supplementation (CT; n = 7). Before and after 6-week treatment, muscle biopsy samples were taken from the vastus lateralis. Nonesterified carnitine and acid-soluble acylcarnitine concentrations were increased in CT (P < 0.05), and serum triacylglycerol concentration was elevated almost twofold in ET and CT (P < 0.05). No interactive effects in FABPc expression were shown from any of treatment groups. Although FABPc increased by 54% in ET compared to CON, it failed to reach statistical significance. In addition, there was no change in FABPc expression from any of experimental groups. Similar trends with FABPc contents were demonstrated in beta-HAD activity. It is concluded that the combination of exercise training and L-carnitine supplementation does not augment in FABPc expression and beta-HAD activity in human skeletal muscle indicating that combined treatment does not exert additive effect in fat metabolism. Thus L-carnitine supplementation would be unlikely to be associated with the enhanced exercise performance.

Medium-chain fatty acids undergo elongation before beta-oxidation in fibroblasts.

Although mitochondrial fatty acid beta-oxidation (FAO) is considered to be well understood, further elucidation of the pathway continues through evaluation of patients with FAO defects. The FAO pathway can be examined by measuring the 3-hydroxy-fatty acid (3-OHFA) intermediates. We present a unique finding in the study of this pathway: the addition of medium-chain fatty acids to the culture media of fibroblasts results in generation of 3-OHFAs which are two carbons longer than the precursor substrate. Cultured skin fibroblasts from normal and LCHAD-deficient individuals were grown in media supplemented with various chain-length fatty acids. The cell-free medium was analyzed for 3-OHFAs by stable-isotope dilution gas-chromatography/mass-spectrometry. Our finding suggests that a novel carbon chain-length elongation process precedes the oxidation of medium-chain fatty acids. This previously undescribed metabolic step may have important implications for the metabolism of medium-chain triglycerides, components in the dietary treatment of a number of disorders.

Differentiation of long-chain fatty acid oxidation disorders using alternative precursors and acylcarnitine profiling in fibroblasts.

The differentiation of carnitine-acylcarnitine translocase deficiency (CACT) from carnitine palmitoyltransferase type II deficiency (CPT-II) and long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency from mitochondrial trifunctional protein deficiency (MTP) continues to be ambiguous using current acylcarnitine profiling techniques either from plasma or blood spots, or in the intact cell system (fibroblasts/amniocytes). Currently, enzyme assays are required to unequivocally differentiate CACT from CPT-II, and LCHAD from MTP. Over the years we have studied the responses of numerous FOD deficient cell lines to both even and odd numbered fatty acids of various chain lengths as well as branched-chain amino acids. In doing so, we discovered diagnostic elevations of unlabeled butyrylcarnitine detected only in CACT deficient cell lines when incubated with a shorter chain fatty acid, [7-2H3]heptanoate plus l-carnitine compared to the routinely used long-chain fatty acid, [16-2H3]palmitate. In monitoring the unlabeled C4/C5 acylcarnitine ratio, further differentiation from ETF/ETF-DH is also achieved. Similarly, incubating LCHAD and MTP deficient cell lines with the long-chain branched fatty acid, pristanic acid, and monitoring the C11/C9 acylcarnitine ratio has allowed differentiation between these disorders. These methods may be considered useful alternatives to specific enzyme assays for differentiation between these long-chain fatty acid oxidation disorders, as well as provide insight into new treatment strategies.

Ginseng administration protects skeletal muscle from oxidative stress induced by acute exercise in rats.

Enzymatic activity was analyzed in the soleus, gastrocnemius (red and white) and plantaris muscles of acutely exercised rats after long-term administration of Panax ginseng extract in order to evaluate the protective role of ginseng against skeletal muscle oxidation. Ginseng extract (3, 10, 100, or 500 mg/kg) was administered orally for three months to male Wistar rats weighing 200 +/- 50 g before exercise and to non-exercised rats (N = 8/group). The results showed a membrane stabilizing capacity of the extract since mitochondrial function measured on the basis of citrate synthase and 3-hydroxyacyl-CoA dehydrogenase activities was reduced, on average, by 20% (P < 0.05) after exercise but the activities remained unchanged in animals treated with a ginseng dose of 100 mg/kg. Glutathione status did not show significant changes after exercise or treatment. Lipid peroxidation, measured on the basis of malondialdehyde levels, was significantly higher in all muscles after exercise, and again was reduced by about 74% (P < 0.05) by the use of ginseng extract. The administration of ginseng extract was able to protect muscle from exercise-induced oxidative stress irrespective of fiber type.