Article

The content of L-carnitine in meat after different methods of heat treatment

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Abstract

Purpose – The objective of this study is to examine the effects of pan‐frying, boiling and cooking in a microwave on the amount of L‐carnitine in meat and to look at its distribution in the surrounding fluid after food processing. Design/methodology/approach – Total carnitine, free carnitine and acylcarnitines were determined in meat samples from beef, pork and poultry (including ostrich) and in a liver sample from beef. The measurements were carried out before and after the specimens were subjected to different heat treatments. A radio‐enzymatic assay was used for measurement of L‐carnitine. Results are expressed per 100 gram dry matter and per 100 gram wet weight. Findings – Except for pan‐frying, virtually no losses of carnitine occurred during the different procedures of heat treatment. During boiling and microwaving, however, a considerable portion of the tissue carnitine escaped into the water fraction. With pan‐frying, carnitine losses from meat amounted to from 3 to 36 per cent. In all animal species, tissue losses of L‐carnitine increased with increase of boiling time. When expressed as a percentage of total carnitine, the proportion of carnitine present as esters differed somewhat between different heating procedures but showed no typical pattern. Originality/value – The findings of this study show the important role that meat products play for providing an adequate amount of L‐carnitine in humans who are suffering from carnitine deficiency and an exogenous supplementation is needed.

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... Its presence in animal tissues has been attributed to biosynthesis from lysine and methionine (Shimada et al., 2004). In animals, L-carnitine (L-Ca) is a cofactor of acetyl-CoA carnitine transferase that facilitates the channeling of activated long-chain fatty acids Brosnan et al. (1973) Carnitine Wu et al. (2003) Carnitine O-octanoyltransferase -octanoyl-CoA + L-carnitine = CoA + L-octanoylcarnitine Jogl et al. (2004) across inner mitochondrial membranes to the sites of enzymatic processes of oxidative degradation (β-oxidation) (Knüttel-Gustavsen & Harmeyer, 2011;Shimada et al., 2004;Szymeczko et al., 2007). It also participates indirectly in lipid transformations as well as the metabolism of carbohydrates and N-containing compounds and in the control of excess acetyl-CoA in the mitochondria by facilitating the formation of acetylcarnitine, which liberates free acetyl-CoA (Knüttel-Gustavsen & Harmeyer, 2011;Strijbis et al., 2010). ...
... In animals, L-carnitine (L-Ca) is a cofactor of acetyl-CoA carnitine transferase that facilitates the channeling of activated long-chain fatty acids Brosnan et al. (1973) Carnitine Wu et al. (2003) Carnitine O-octanoyltransferase -octanoyl-CoA + L-carnitine = CoA + L-octanoylcarnitine Jogl et al. (2004) across inner mitochondrial membranes to the sites of enzymatic processes of oxidative degradation (β-oxidation) (Knüttel-Gustavsen & Harmeyer, 2011;Shimada et al., 2004;Szymeczko et al., 2007). It also participates indirectly in lipid transformations as well as the metabolism of carbohydrates and N-containing compounds and in the control of excess acetyl-CoA in the mitochondria by facilitating the formation of acetylcarnitine, which liberates free acetyl-CoA (Knüttel-Gustavsen & Harmeyer, 2011;Strijbis et al., 2010). A deficiency in dietary L-CA in animal diets can cause muscle weakness and dysfunction of the heart and skeletal muscles (Knüttel-Gustavsen & Harmeyer, 2011). ...
... It also participates indirectly in lipid transformations as well as the metabolism of carbohydrates and N-containing compounds and in the control of excess acetyl-CoA in the mitochondria by facilitating the formation of acetylcarnitine, which liberates free acetyl-CoA (Knüttel-Gustavsen & Harmeyer, 2011;Strijbis et al., 2010). A deficiency in dietary L-CA in animal diets can cause muscle weakness and dysfunction of the heart and skeletal muscles (Knüttel-Gustavsen & Harmeyer, 2011). Besides its availability from dietary sources, L-CA is biosynthesized from N ε -trimethyllysine (TML), which is an alpha-amino acid bearing a quaternary ammonium compound. ...
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The use of total volatile basic nitrogen (TVB‐N) as a quality parameter for fish is rapidly growing to include other types of meat. Investigations of meat quality have recently focused on TVB‐N as an index of freshness, but little is known on the biochemical pathways involved in its generation. Furthermore, TVB‐N and methylated amines have been reported to exert deterimental health effects, but the relationship between these compounds and human health has not been critically reviewed. Here, literature on the formative pathways of TVB‐N has been reviewed in depth. The association of methylated amines and human health has been critically evaluated. Interventions to mitigate the effects of TVB‐N on human health are discussed. TVB‐N levels in meat can be influenced by the diet of an animal, which calls for careful consideration when using TVB‐N thresholds for regulatory purposes. Bacterial contamination and temperature abuse contribute to significant levels of post‐mortem TVB‐N increases. Therefore, controlling spoilage factors through a good level of hygiene during processing and preservation techniques may contribute to a substantial reduction of TVB‐N. Trimethylamine (TMA) constitutes a significant part of TVB‐N. TMA and trimethylamine oxide (TMA‐N‐O) have been related to the pathogenesis of noncommunicable diseases, including atherosclerosis, cancers, and diabetes. Proposed methods for mitigation of TMA and TMA‐N‐O accumulation are discussed, which include a reduction in their daily dietary intake, control of internal production pathways by targeting gut microbiota, and inhibition of flavin monooxygenase 3 enzymes. The levels of TMA and TMA‐N‐O have significant health effects, and this should, therefore, be considered when evaluating meat quality and acceptability. Agreed international values for TVB‐N and TMA in meat products are required. The role of feed, gut microbiota, and translocation of methylated amines to muscles in farmed animals requires further investigation.
... L-carnitine, commonly refered to as carnitine, is a natural and biologically active amino acid derivative, which transports activated long chain fatty acids from the cytosol into mitochondria for subsequent β-oxidation, and supports other physiological activities (Knüttel-Gustavsen & Harmeyer, 2011;Wang et al., 2018). Carnitine is not considered an essential nutrient (Vaz & Wanders, 1982), although it might be regarded as a conditionally essential nutrient during certain physiological conditions. ...
... With regard to the meat carnitine content, raw meat from beef contains c.a. 70 mg/100g, chicken 10 mg/100g, turkey 21 mg/ 100g, duck 27 mg/100g, lamb 40 mg/100g and pork 30 mg/100g (Demarquoy et al., 2004). However, depending on the cooking process that the meat underwent, the carnitine content can drop up to 50% (Knüttel-Gustavsen & Harmeyer, 2011). Thus, the cooking process seems to substantially alter the content of this nutrient, which is of utmost interest in order to calculate carnitine intake. ...
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The assessment of the actual contribution of red or processed meat to increasing the risk of suffering cardiovascular diseases (CVD) requires identification of specific harmful components and their underlying pathological mechanisms. In regards to CVD, meat lipids and their oxidation products have been recurrently studied due to their implications on lipid metabolism, hypercholesterolemia, obesity, and risk of suffering vascular events such as stroke. The impact of excess NaCl intake on increasing blood pressure is well-established and processed meat products have been recognized as a major contributor to dietary sodium in developed countries. Recent evidence has also suggested carnitine from red meat, as a precursor for trimethylamine-N-oxide, which has been shown to cause atherosclerosis, may increase the risk of suffering CVD in experimental animals. The present review aims to provide an updated overview, including evidence, controversies and unresolved questions on both the epidemiology and mechanisms relating red and processed meat consumption to CVD.
... The significant depletions observed in the carnosine, anserine, betaine and carnitine contents of KNC meat during boiling (Table 1) can be explained in relation to the higher water solubility of these compounds, 4,7,16,35 which increases their rate of loss into the cooking liquor. Creatine is non-enzymatically converted into creatinine in muscle systems by the removal of water and the formation of a ring structure. ...
... In addition, increasing the boiling time resulted in increased losses of carnitine. 16 Therefore the cooking method and conditions, including the temperature and duration, may affect the loss of these compounds from meat into the cooking liquor during thermal processing. ...
Article
Background In this study, we determined the effects of sex, meat cut, and thermal processing on the carnosine, anserine, creatine, betaine, and carnitine contents of the Korean native chicken (KNC) meat. A total of 40 one-day-old chicks (20 chicks of each sex), from a commercial KNC strain (WoorimatdagTM) were reared under similar standard commercial conditions with similar diets, and a total of 10 birds of each sex were randomly selected and slaughtered at 14 weeks of age. Raw and cooked meat samples were prepared from both breast and leg meats and analyzed for the aforementioned functional compounds.ResultsFemale KNCs had significantly higher betaine and creatine contents. The breast meat showed significantly higher carnosine and anserine contents, whereas the leg meat had a greater betaine and carnitine content. The content of all functional compounds was significantly depleted by thermal processing.Conclusion This study confirms that KNC meat is a good source of above-mentioned functional compounds, which can be considered attractive nutritional quality factors. However, their concentrations were significantly affected by thermal processing conditions, meat cut, and sex. Further experiments are needed to select the best thermal processing method to preserve these functional compounds.
... Kanningar eru gjørdar av haru, og verða hesi úrslitini útgivin í naestum. Kanningar vísa, at viðgerð, so sum kóking og steiking, ávirkar innihaldið av karnitini í matvørunum negativt, men karnitinið verður funnið aftur í soðnum (KnuttelGustavsen & Harmeyer, 2011og Rigault et al., 2008. Hetta vísir týdningin av okkara vanligu føroysku matgerð, at brúka soðið til súpan og sós. ...
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... Important bioactive compounds in meat include coenzyme Q 10 , taurine, conjugated linoleic acid (CLA), glutathione, lipoic acid, betaine, L-carnitine, creatine, carnosine, and anserine (Schmid, 2009). Previous studies have shown that the content of the mentioned functional compounds in meat is generally determined by several factors, including species, breed, age, sex, muscle type, and thermal processing (Alirezaei et al., 2012;Knüttel-Gustavsen and Harmeyer, 2011;Mora et al., 2010;Purchas et al., 2004). Poultry meat naturally contains a higher content of anserine than beef and pork (Abe and Okuma, 1995). ...
Chapter
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We designed this study to re-validate some methodological parameters of the radio-enzymatic assay, including phenomena of residual, non-carnitine radioactivity present in some assay mixtures of food samples. The second part of the paper presents l-carnitine concentrations (total-, free- and acyl-carnitine) in a wide range of food samples of animal and plant origin.Due to an appropriate procedure of sample preparation and an elimination of influencing factors in the biological samples, more homogeneous and reliable results were obtained and smaller variances between the sample duplicates were obtained. For total and free carnitine, the inter-assay variances of the method were 6.5% and 7.2%, respectively. The lower limit of detection was 0.11 μmol carnitine/l of assay mixture.The highest carnitine contents were found in muscle from kangaroo (6370 mg/kg DM (dry matter)) and horse (4230 mg/kg DM), followed by different cattle meats (3320–1870 mg/kg DM). The carnitine content in the tissues from pigs and fowls ranged from 135 to 830 mg/kg DM. The carnitine content in most dairy products ranged, approximately, between animal tissues and plant-derived food with concentrations ranging from 8 to 530 mg/kg DM.The method was found to be easily and rapidly usable for the determination of l-carnitine in complex biological samples.
Article
l-Carnitine is a vitamin-like nutrient essential for energy production and lipid metabolism in many organs and tissues such as skeletal muscle and heart. Even if l-carnitine can be synthesized, most of the carnitine present in human body is provided by food. Until now, no large study has been conducted where the content in l-carnitine of various foods was analyzed. The objective of this study was to determine the level of free l-carnitine present in food commonly consumed in Western countries. A radioisotopic assay was used to estimate l-carnitine content in raw and processed foods. From this study, it clearly appeared that meat products were the best sources for l-carnitine. Dairy products, seafood and fish are generally relatively low in carnitine whereas vegetables are mostly very low in carnitine. An omnivorous regimen allows to meet the general recommendation on l-carnitine intake. Vegetarian are clearly below recommendation and their carnitine homeostasis has to be carried out by a functional biosynthesis.
Article
We have adapted the enzymatic method [Biochemical and Biophysical Research Communications 176 (3) (1991) 1617] for the safe and rapid assay of L-carnitine (L-CA) in skeletal muscle using a microplate reader. The concentration of L-CA in fresh semitendinosus muscle from broiler chicken, pig, beef cattle, deer, horse and goat muscle were 0.69, 1.09, 1.86-3.57, 4.57, 4.95 and 11.36 μmol/g wet weight, respectively. The animals which had higher concentration of L-CA, also had the highest amounts of myoglobin as an index to the redness of the muscle. Furthermore, we investigated this relationship between white muscle, M. pectoralis profundus, and red muscle, M. soleus, in laying hens. The L-CA and myoglobin concentration in red muscle were significantly higher than those in white muscle (p<0.01). These findings suggest that L-CA concentration in muscle is related to oxygen metabolism and to myofiber types.
Article
Human adults store around 20g of l-carnitine. In the human body, l-carnitine is not metabolized but excreted through the kidney. Lost l-carnitine has to be replenished either by a biosynthetic mechanism or by the consumption of foods containing l-carnitine. Today, there is no "official" recommended daily allowance for l-carnitine but the daily need for l-carnitine intake has been estimated in the wide range of 2-12μmol/day/kg body weight for an adult human. In this study we evaluated the effect of freezing and of different cooking methods on the l-carnitine content of red meat and fish. l-carnitine was abundantly present in all beef products analyzed. The amounts in the various cuts were similar and our data showed that freezing or cooking did not modify l-carnitine content. Salmon contained about 12 times less l-carnitine than beef but except in smoked salmon, cooking or freezing did not alter l-carnitine content. This study confirms the important role that meet products play for providing adequate amount of l-carnitine to the human body.
Article
Systemic primary carnitine deficiency is an autosomal recessive disorder of the carnitine cycle caused by mutations in the SLC22A5 gene that encodes the carnitine transporter, organic cation transporter. Systemic primary carnitine deficiency typically presents in childhood with either metabolic decompensation or cardiomyopathy. We report five families in which low free carnitine levels in the infants' newborn screening have led to the diagnosis of maternal systemic primary carnitine deficiency. Blood samples from the infants and /or their family members were used to extract the DNA. The entire coding regions of the SLC22A5 gene were sequenced. The clinical data were obtained from the referring metabolic specialists. Sequencing the SLC22A5 gene allowed molecular confirmation with identification of three novel mutations: c.1195C>T (p.R399W), c.1324_1325GC>AT (p.A442I), and c.43G>T (p.G15W). All infants were asymptomatic at the time of diagnosis, and one was found to have systemic primary carnitine deficiency. Three mothers are asymptomatic, one had decreased stamina during pregnancy, and one has mild fatigability and developed preeclampsia. These findings provide further evidence that systemic primary carnitine deficiency presents with a broad clinical spectrum from a metabolic decompensation in infancy to an asymptomatic adult. The maternal systemic primary carnitine deficiency was uncovered by the newborn screening results supporting the previous notion that newborn screening can identify some of the maternal inborn errors of metabolism. It also emphasizes the importance of maternal evaluation after identification of a low free carnitine level in the newborn screening.
Article
Studies in humans and animals demonstrate that "lipid over supply" causes or worsens insulin resistance via multiple mechanisms involving the accumulation of intracellular lipids in multiple tissues. In particular, the accumulation of fatty acyl CoA derivatives/metabolites in muscle inhibits both insulin signaling and glucose oxidation. Therefore agents that ameliorate the accumulation of fatty acyl CoA derivatives and/or their metabolites would be beneficial in the treatment or prevention of insulin resistance and T2D. Hyperinsulemic/euglycemic clamp studies in humans and carnitine supplementation studies in rodents provide "proof-of-concept" that carnitine is effective at improving insulin-stimulated glucose utilization and in reversing abnormalities of fuel metabolism associated with T2D. Carefully controlled clinical trials are warranted to determine the efficacy dietary carnitine supplementation as an adjunctive treatment for type 2 diabetes.
Article
This study examined the impact of L-acetylcarnitine treatment on metabolic parameters and body composition in patients with lipodystrophy syndrome secondary to antiretroviral treatment in human immunodeficiency virus (HIV) infection. A total of 9 HIV-1 infected patients with lipodystrophy syndrome (4F/5M, age 41+/-5 years, HIV duration 8+/-2 years, BMI 23.7+/-3.4 kg/m(2), on protease inhibitors and nucleoside analogue Reverse Transcriptase inhibitors) were evaluated before and after 8 months of therapy with L-acetylcarnitine (2 g/die) and 9 matched healthy subjects served as control subjects. In all patients fasting plasma glucose, insulin concentrations (for evaluation of surrogate indexes of insulin sensitivity), lipid profile, lipid oxidation (by indirect calorimetry), body composition (by DEXA), and intramyocellular triglyceride (IMCL) content of the calf muscles (by (1)H NMR spectroscopy) were assessed. After this therapy, in HIV-1 patients, the IMCL content of the soleus had significantly decreased (p=0.03). Plasma FFAs (0.79+/-0.31 to 0.64+/-0.25; p<0.05) and Respiratory Quotient (0.83+/-0.18 to 0.72+/-0.16; p<0.03) also decreased. Insulin sensitivity was significantly lower prior (HOMA-IS 0.56+/-0.30) and nonstatistically different than controls after therapy (0.72+/-0.49 vs. 0.78+/-0.42) whilst the percentage of fat in the legs increased (p=0.05). Eight months of L-acetylcarnitine treatment increased lipid oxidation, decreased intramyocellular triglyceride content, and induced a more physiological distribution of fat deposits.
Article
Carnitine deficiency is prevalent in populations with chronic illness, including cancer. In a recent open-label study, L-carnitine supplementation was well tolerated and appeared to improve fatigue and other outcomes in cancer patients. To further evaluate this finding, adult patients with advanced cancer, carnitine deficiency (free carnitine more than 35 micromol/L for males or less than 25 micromol/L for females, or acyl/free carnitine ratio of more than 0.4), moderate to severe fatigue, and a Karnofsky Performance Status (KPS) score of 50 or more, were randomly assigned to receive either L-carnitine (0.5 g/day for two days, followed by 1g/day for two days, and then 2g/day for 10 days) or placebo. This double-blind phase was followed by an open-label phase, during which all patients received L-carnitine supplementation for two weeks. Outcomes included the fatigue subscale of the Functional Assessment of Cancer Therapy-Anemia (FACT-An), the Linear Analog Scale Assessments (LASA), the Mini-Mental State Exam (MMSE), and the KPS. Twenty-nine patients (12 placebo, 17 L-carnitine) were included in the intent-to-treat (ITT) analysis. From baseline to the end of the double-blind phase, serum total and free L-carnitine increased from 32.9+/-3.8 to 56.6+/-20.5 (P=0.004), and from 22.9+/-19.4 to 45.3+/-17.2 (P=0.004), respectively, in the L-carnitine-treated group, and from 28.2+/-10.2 to 36.2+/-8.7 (P=ns), and from 22.6+/-7.9 to 28.7+/-8.6 (P=ns) in the placebo group, respectively. The planned ITT analysis revealed no significant improvement in any of the study's endpoints, and these negative findings were not different when data from two patients who did not adhere to the protocol were eliminated. However, an exploratory covariate analysis that excluded these two protocol violators and included outcome data from both the double-blind and open-label phases demonstrated significantly improved fatigue on the FACT-An fatigue subscale (P<0.03), and significantly improved FACT-An functional well-being subscale (P<0.03), and KPS (P<0.003), in the group that started with L-carnitine during the double-blind phase. These data do not support the conclusion that L-carnitine in the doses tested reverses cancer-related fatigue in carnitine-deficient patients. However, L-carnitine supplementation does increase L-carnitine serum levels, and the positive findings in an exploratory analysis justify a larger study to determine if this strategy could be of benefit for a subpopulation of cancer patients.
Article
L-Carnitine has been described as a "conditionally essential" nutrient for humans. Segments of the human population suggested as having a requirement for carnitine include infants (premature and full-term), patients on long-term parenteral nutrition, and perhaps children. The evidence to support these claims includes 1) low circulating carnitine concentrations; 2) abnormal (or at least different) circulating metabolite concentrations (free fatty acids, triglycerides, ketone bodies), and 3) very limited and inconsistent growth data. A number of subjective observations and anecdotal case reports have been offered in support of a requirement for carnitine. Exogenous carnitine is required to maintain "normal" (in the epidemiologic sense) plasma or serum carnitine concentrations in humans of all ages. But "functional carnitine deficiency," defined by abnormal clinical presentation correctable by carnitine administration, has not been demonstrated in an otherwise normal (nonpathologic) population. On the other hand, nutritional or pharmacological intervention with carnitine or its esters may be beneficial for very premature infants, infants and children with various clinical conditions associated with low circulating carnitine concentrations, and in some chronic diseases associated with the aging process.
For any given tissue the normal carnitine content is that which is necessary for an optimal rate of long-chain fatty acid oxidation. Tissues especially rich in carnitine are liver, muscle and heart. The endogenous rate of carnitine biosynthesis from lysine and methionine is not known to be influenced by fluctuations in the levels of the parent amino acids, as exemplified by hypermethioninaemic patients. Inadequate dietary supply of carnitine, leading to a deficiency, may occur in vegetarians and especially in subjects on total parenteral nutrition. Premature babies are especially at risk in this respect, and this has led to the addition of carnitine to solutions for intravenous alimentation. It has been suggested that carnitine plays an important role in the intramitochondrial regulations of coenzyme A homeostasis by expelling short-chain and medium-chain acyl groups from the mitochondrion in the form of acylcarnitines. These esters are preferentially excreted into the urine and thus result in a depletion of the body's carnitine stores. Important conditions in this respect are the inherited organic acidurias and disorders of fatty acid oxidation. Urinary acylcarnitines can be identified by indirect gas chromatographic or direct mass spectrometric methods. Patients on haemodialysis treatment will lose carnitine in the dialysis fluid, whereas excessive urinary losses of free and acetylated carnitine occur in the Fanconi syndrome. Secondary carnitine deficiency may be accompanied by a moderate degree of muscular dysfunction. Reassuringly, however, no signs of hepatic or cardiac involvement, as often seen in primary carnitine deficiency, have been observed.
Article
Plasma carnitine "insufficiency," (plasma esterified carnitine to free carnitine ratio above 0.25) was found in 21 of 48 (43.8%) patients with mitochondrial myopathy, of whom 4 also showed both total and free carnitine deficiencies in plasma. In addition, plasma levels of SCAC and LCAC were higher in patients with mitochondrial myopathy than in controls (P < 0.001 and P < 0.01, respectively). Patients diagnosed as having plasma carnitine insufficiency or deficiency were treated with L-carnitine (50-200 mg/kg per day in four daily doses). Muscle weakness improved in 19 of 20 patients, failure to thrive in 4 of 8, encephalopathy in 1 of 9, and cardiomyopathy in 8 of 8 patients. Plasma carnitine "insufficiency" provides an additional clue to the diagnosis of mitochondrial myopathy and an indication for L-carnitine therapy.
Article
Total-, free-, and acylcarnitine concentrations were determined in whole blood, plasma, and red blood cells of 88 women during pregnancy. Already in the 12th week of gestation the mean whole blood carnitine level was significantly (p < 0.01) lower than those of the controls. From the 12th gestational week up to parturition there was a further significant (p < 0.01) decrease. This reduction of total carnitine in whole bloods was mainly caused by a significant (p < 0.01) decrease of free carnitine levels, since no marked changes of short chain acylcarnitine values were found throughout pregnancy. The contribution of red blood cell L-carnitine to whole blood carnitine increased significantly (p < 0.05) to 61% at delivery versus 39% (controls). In umbilical cord blood free and total carnitine levels were significantly (p < 0.05) higher than the corresponding maternal levels. The contribution of red blood cell L-carnitine to whole blood carnitine was higher in cord blood than in maternal blood. The results of the present study demonstrate that during pregnancy whole blood and plasma carnitine levels decrease to those levels found in patients with carnitine deficiency. Also the percentage of acylcarnitine on total carnitine, found in the present study, is characteristic for a secondary carnitine deficiency. Thus L-carnitine substitution in pregnant women, especially in risk pregnancies, may be advantageous.
Article
Carnitine deficiency presents as a major problem in fatty acid oxidation. The use of a plasma carnitine assay can rapidly help to describe this deficiency. The method we describe here requires two simple steps of sample preparation, followed by automated analysis with the Beckman Synchron CX4 random-access chemistry analyzer. The goal of this method development was to reduce the cost of analysis and to allow a greater number of laboratories to perform this assay on demand within 1 h for both free and total carnitine. The method has a linearity of 0-150 micromol/L and a detection limit of 5 micromol/L. The inter- and intraday CVs are <20%. The method agreed closely with both the widely used RIA and spectrophotometric methods.
Article
To determine the serum free carnitine concentration in normally nourished children and in children with kwashiorkor and to relate the carnitine concentration to the ability to oxidise exogenous long chain fatty acids in the body. A cross-sectional comparative study of two age-matched groups. Forty seven children with kwashiorkor and 47 age-matched normally nourished children. Fasting blood samples were enzymatically analysed for free carnitine levels. 13C labelled hiolein was administered orally and the recovery of 13C from the breath air was monitored after administration of the feed. The cumulative per cent dose (CUMPD) recovery of 13C 16 hours after the ingestion of labelled hiolein was determined. Normal children had significantly higher free carnitine concentrations (mean = 60.7 mumol/l; 95% confidence interval of the mean = 42.7-77.8) than the kwashiorkor children (mean = 16.5 mumol/l; 95% confidence interval of the mean = 11.3-19.8)(p < 0.001). There was no correlation between serum free carnitine concentration and serum albumin in kwashiorkor subjects, but there was a significant correlation between serum free carnitine concentration and the degree of weight loss as indicated by the weight: weight for age and sex ratio. The greater the weight loss, the lower the serum carnitine concentration amongst the kwashiorkor children (r = 0.46; p < 0.01). There was a linear relationship between serum free carnitine and hiolein oxidation (r = 0.89; p < 0.001). There is carnitine deficiency in kwashiorkor, and that the impaired lipid oxidation in kwashiorkor is related to this deficiency.
Article
We describe a patient with carnitine-acylcarnitine translocase deficiency (MIM 212138), who presented with neonatal generalized seizures, heart failure, and coma. Laboratory evaluation revealed hypoglycemia, hyperammonemia, lactic acidemia, hyperuricemia, and mild dicarboxylic aciduria. The fact that total plasma carnitine (7.1 micromol/l [20-30]) and free carnitine (1.9 micromol/l [12-18]) were low together with a high acylcarnitine/free carnitine ratio of 2.7 [0.4-1.0] prompted acylcarnitine analysis. This revealed the presence of large amounts of long-chain derivatives including C(16:0), C(16:1), C(18:1), C(18:2). Based on these findings carnitine-acylcarnitine translocase deficiency was suspected which was confirmed by enzyme studies in fibroblasts. The underlying complex metabolic consequences of this defect are reviewed. Prenatal diagnosis was performed in a subsequent pregnancy and a defect ruled out by measurement of carnitine-acylcarnitine translocase activity in cultured chorionic villi cells. As the clinical recognition of a life-threatening fatty acid oxidation disorder may be difficult, defects in this pathway should be considered in any child with coma, an episode of a Reye-like syndrome, and cardiomyopathy. Since routine laboratory tests often do not provide clues about potential disorders and profiles of urinary organic acids may not be characteristic, we recommend to measure free carnitine and acylcarnitines in plasma in any child with hyperammonemia, hypo/hyperketotic hypoglycemia or lactic acidemia for prompt treatment, proper genetic counseling, and potential prenatal diagnosis.
Article
The intracellular homeostasis is controlled by different membrane transporters. Organic cation transporters function primarily in the elimination of cationic drugs, endogenous amines, and other xenobiotics in tissues such as the kidney, intestine, and liver. Among these molecules, carnitine is an endogenous amine which is an essential cofactor for mitochondrial beta-oxidation. Recently, a new family of transporters, named OCT (organic cation transporters) has been described. In this minireview, we present the recent knowledge about OCT and focus on carnitine transport, more particularly by the OCTN2. The importance of this sodium-dependent carnitine cotransporter, OCTN2, comes from various recently reported mutations in the gene which give rise to the primary systemic carnitine deficiency (SCD; OMIM 212140). The SCD is an autosomal recessive disorder of fatty acid oxidation characterized by skeletal myopathy, progressive cardiomyopathy, hypoglycemia and hyperammonemia. Most of the OCTN2 mutations identified in humans with SCD result in loss of carnitine transport function. Identifying these mutations will allow an easy targeting of the SCD syndrome. The characteristics of the juvenile visceral steatosis (jvs) mouse, an animal model of SCD showing similar symptoms as humans having this genetic disorder, are also described. These mice have a mutation in the gene encoding the mouse carnitine transporter octn2. Although various OCTN carnitine transporters have been identified and functionally characterized, their membrane localization and regulation are still unknown and must be investigated. This knowledge will also help in designing new drugs that regulate carnitine transport activity.
Article
Fetal defects in mitochondrial beta-oxidation have been linked with an increased risk for acute fatty liver of pregnancy and preeclampsia-related conditions. A woman with previously undiagnosed carnitine palmitoyltransferase 1 deficiency experienced hemolysis, elevated liver enzymes, low platelets-like syndrome late in her first pregnancy with an unaffected fetus. Carnitine palmitoyltransferase 1 deficiency should be considered as a potential cause of life-threatening complications of pregnancy.
Article
Carnitine deficiency is a potential cause of metabolic crisis during periods of high energy demand or stress. Affected individuals have very low carnitine levels in blood, decreased carnitine transport in fibroblasts, and commonly have mutations in the OCTN2 gene. We report management through pregnancy and delivery of a patient with carnitine deficiency who had reduced carnitine transport in fibroblasts, but no mutations in the OCTN2 gene. Carnitine deficiency can be treated with exogenous carnitine in select patients during pregnancy. This is especially helpful, because carnitine levels decrease during pregnancy in normal individuals, and neonates are dependent on exogenous carnitine.
Role of carnitine biosynthesis and renal conservation of carnitine in genetic and acquired disorders of carnitine metabolism
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Loss of L-carnitine from beef during cooking
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Maternal systemic primarv carnitine deflciency uncovered by newborn screening: clinical. biochemical, and molecular aspects
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Bestimmung von L-Carnitin und seiner Ester in Lebensmitteln
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Is camitine an essential nutrients in humans?
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Corresponding author Sehne Knüttel-Gustavsen can be contacted at: segust@ginx.net To purchase reprints of this article please e-mail: reprints~lJemeraIclinsight.com Or visit our web site for further details
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Wan, L. and Hubbard, R.W. (1998), "Determination of free and total carnitine with a random-access chemistry analyzer", Clinical Chemisby, Vol. 4-4 No. 4, pp. 810-6. Corresponding author Sehne Knüttel-Gustavsen can be contacted at: segust@ginx.net To purchase reprints of this article please e-mail: reprints~lJemeraIclinsight.com Or visit our web site for further details: www.emeraldinsight.com/reprints
Einfluss einer L-Carnitinzulage im Futter von hochtragenden und säugenden Sauen auf die Aufzuchtleistung und den Carnitinstatus bei Sauen und Ferkel
  • U Kaise