Effects Of Carnitine Administration Research Articles

SERUM ACYLCARNITINE CONCENTRATION IS ELEVATED IN PATIENTS WITH ACUTE DECOMPENSATED HEART FAILURE

Carnitine is a key molecule for mitochondrial fatty acid β-oxidation, and previous reports have suggested beneficial effects of carnitine administration on heart failure (HF) patients. However, little is known about the change of systemic carnitine homeostasis in HF patients. We measured serum

Carnitine is necessary to maintain the phenotype and function of brown adipose tissue

The juvenile visceral steatosis (JVS) mouse is a mutant strain with an inherited systemic carnitine deficiency. Mice of this strain show clinical signs attributable to impaired heat production and disturbed energy production. Brown adipose tissue (BAT) is the primary site of non-shivering thermogenesis in the presence of uncoupling protein-1 (UCP-1) in rodents and humans, especially in infants. To investigate the possible cause of impaired heat production in BAT, we studied the morphological features, carnitine concentration, and UCP-1 production of BAT in JVS mice. The effect of carnitine administration on these parameters was also examined. JVS mice aged 5 or 10 days (60 each) and age-matched control mice were used in this study, along with 10-day-old JVS mice treated subcutaneously with L-carnitine once a day between postpartum days 5 and 10. JVS mice showed lower body temperatures and lower concentrations of carnitine in BAT. Morphologically, BAT cells in JVS mice contained large lipid vacuoles and small mitochondria, similar to those present in white adipose tissue cells. In addition, UCP-1 mRNA and protein expression levels were significantly reduced in JVS as compared with control mice. Carnitine treatment resulted in significant increases in body temperature and carnitine concentrations in BAT, together with the recovery of normal morphological features. UCP-1 mRNA and protein expression levels were also significantly increased. These findings strongly suggest that carnitine is essential for maintaining the function and morphology of BAT.

Effects of Carnitine Administration and Voluntary Exercise on the Lipid Metabolism of Rats Fed on a High-Fat Diet

Effects of Carnitine Administration and Voluntary Exercise on the Lipid Metabolism of Rats Fed on a High-Fat Diet

Carnitine affects fatty acid metabolism after cardioplegic arrest in neonatal rabbit hearts

Background. Fatty acid (FA) metabolism and the contribution of carnitine to metabolism after cardioplegic arrest still remain unclear, especially in the neonatal heart where β-oxidation is not a predominant source of adenosine triphosphate. Methods. FA metabolism and the effects of carnitine administration were evaluated using a newborn (7-day-old) rabbit blood-perfused Langendorff model subjected to cold cardioplegic arrest. The hearts were divided into five groups; (1) perfused with unmodified diluted blood (n = 9), (2) subjected to 180 minutes of cold cardioplegic arrest and reperfused with the blood (n = 9), (3) subjected to the same ischemia and reperfused with the blood containing 40 μM/L (n = 9), (4) 0.5 mM/L (n = 5), and (5) 5 mM/L of carnitine (n = 5). During reperfusion, FA metabolism was assessed by iodine-123-labeled 15-(p-iodophenyl)-3-(R,S)-methylpentadecanoic acid, a fatty acid. The myocardial time-radioactivity curve was then determined and a mathematical compartment analysis of the external detection was used to elucidate FA metabolism in the cardiac myocyte. Results. Cold cardioplegic arrest resulted in significantly impaired FA metabolism following reperfusion. Compartment analysis suggested that FA activation in the cytosol and β-oxidation were impaired. Carnitine supplementation in groups 3 and 4 improved FA metabolism during reperfusion. In contrast, supplementation in group 5 had no beneficial effect on FA metabolism. Conclusions. These results suggest that FA metabolism is impaired after cold cardioplegic arrest and that carnitine supplementation may improve aerobic metabolism in neonates after open heart surgery.

Letters to the Editor

We read with interest the report of Drs Hunt and Pellock on screening a population of institutionalized patients for carnitine deficiency. There did not appear to be any substantial correlation between the carnitine levels and the patient's function, handicap, or the ingestion of anticonvulsants. This population could be useful for a blinded test of the reported beneficial effects of carnitine administration. The letter from Sigma-Tau Pharmaceuticals, manufacturers of Carnitor, is, I believe, an intentionally misleading and disingenuous extension of their advertising campaign of which my quote is the opening sentence.

Preliminary study on the effect of short-term carnitine treatment on nucleic acids and protein metabolism in sea bass ( Dicentrarchus labrax L.) fry

We used labelled precursors to verify our previous hypothesis on the effects of carnitine administration on metabolism in sea bass fry. Carnitine treatment significantly enhances the rate of leucine incorporation in sea bass fry. A slight effect is observable in the incorporation rate of 3H-uridine whereas no effect is demonstrable in the incorporation rate of 3H-thymidine.

Effect of carnitine administration on levels of lipid peroxides and activities of superoxide dismutase and catalase in isoproterenol-induced myocardial infarction in rats

The effect of carnitine administration on levels of lipid peroxide and activities of superoxide dismutase and catalase was studied in rats administered isoproterenol to induce myocardial infarction. Levels of fatty acid were lower in rats pretreated with carnitine at the peak period and given isoproterenol than the levels in isoproterenoltreated control rats. Lipid peroxides were decreased in the heart at peak infarction in carnitine-treated rats compared to the levels in isoproterenol-treated controls. Activities of superoxide dismutase and catalase showed no change in carnitine-treated animals given isoproterenol compared to those in normal control rats, while they decreased in animals treated with isoproterenol alone.

The effect of marathon running on carnitine metabolism and on some aspects of muscle mitochondrial activities and antioxidant mechanisms

Carnitine is an essential co-factor in the catabolism of fats as an energy source. The primary purpose of this study was to investigate the effect of running a marathon on the metabolism of carnitine by endurance-trained athletes, and to evaluate the effect of carnitine administration on the performance of such exercise. The effects of marathon running on mitochondrial enzymes and cellular anti-oxidants were also examined to assess whether the expression of these activities is altered by exercise. Subjects were 10 experienced male marathon runners aged between 19 and 25 years. Running a marathon caused a fall in the plasma content of unesterified carnitine (37%) and an increase in the level of acetylcarnitine present (288%). Loading of the athletes with L-carnitine for 10 days before running a marathon abolished the exercise-induced fall in plasma-free carnitine (P less than 0.05) whilst amplifying the production of acetylcarnitine (P less than 0.05). Carnitine loading of the athletes studied made no detectable improvement in performance of the marathon (P greater than 0.05). Cytochrome oxidase, succinate cytochrome C reductase and superoxide dismutase activities present in skeletal muscle were unaltered by marathon running. However, such exercise caused a large increase in the tissue content of oxidized glutathione (189%) at the expense of reduced glutathione (-18%).

Effect of carnitine on lipid metabolism in the neonate. II. Carnitine addition to lipid infusion during prolonged total parenteral nutrition

The effect of carnitine administration on lipid metabolism and carnitine and acylcarnitine plasma values of newborn infants, given total parenteral nutrition for the first 7 days of life, was studied during a 4-hour infusion of Intralipid. An increase in plasma concentrations of total carnitine, free carnitine, and short-chain and long-chain acylcarnitine was found, but no significant change in triglycerides, free fatty acids, glycerol, or beta-hydroxybutyrate plasma values was noted, as compared with values obtained without carnitine administration. Moreover, the low free carnitine and short-chain and long-chain acylcarnitine plasma levels found in newborn infants after 7 days of total parenteral nutrition did not seem to impair the utilization of infused lipids. The results support the concept that the relation between the carnitine pool and lipid metabolism can be influenced by intravenous glucose infusion. Low carnitine plasma concentrations do not necessarily signify a depletion of body carnitine, and sufficient tissue carnitine concentrations can probably maintain good lipid utilization for an extended period.