Dietary Carnitine Research Articles

Carnitine Supplementation Ameliorates the Steatosis and Ketosis Induced by Pivalate in Rats

These studies examined the effect in rats of carnitine supplementation on variables of fat metabolism altered by administration of sodium pivalate, a compound which induces a carnitine deficiency. Weanling male rats received 20 mmol/L sodium pivalate or 20 mmol/L sodium bicarbonate in their drinking water for 2 wk. They were food-deprived for 24 h, and to maximize fatty acid oxidation, were cold-stressed for 4 h. In Experiment 1, group 1 received the bicarbonate, group 2 received the pivalate, group 3 received the pivalate and 0.46 mmol L-carnitine in the diet/d, while group 4 received the pivalate and 0.95 mmol L-carnitine in the diet/d. In Experiment 2, group 1 received unsupplemented drinking water, group 2 received the bicarbonate, group 3 received the pivalate, and group 4 received the pivalate and 0.95 mmol L-carnitine in the diet/d. Pivalate-treated rats given the low carnitine diet had plasma and liver triglyceride levels (Experiment 1), plasma β-hydroxybutyrate concentrations (Experiments 1 and 2) and urinary dicarboxylic acid excretion (Experiment 2) significantly greater than those of controls (P < 0.05). The reduced tissue carnitine concentrations, starvation ketosis and lipid accumulation in the liver are findings also reported for human secondary carnitine deficiency due to organic acidurias. Supplementing the diet with L-carnitine at the level of 0.95 mmol/d significantly raised plasma and tissue carnitine concentrations and reduced the plasma β-hydroxybutyrate and liver triglyceride concentrations to levels not significantly different than control values. Carnitine supplementation ameliorates the degree of liver lipid accumulation and exaggerated starvation ketosis induced by pivalate.

Atlantic Salmon (Salmo salar) Fed L-Carnitine Exhibit Altered Intermediary Metabolism and Reduced Tissue Lipid, but No Change in Growth Rate

Metabolic evidence was sought to explain the reduced body fat and increased body protein observed in Atlantic salmon fed diets supplemented with L-carnitine. By stimulating fatty acid oxidation, dietary carnitine might increase flux through pyruvate carboxylase and decrease flux through the branched-chain α-keto acid dehydrogenase complex, by increasing regulatory ratios of acetyl CoA:free enzyme A (CoA-SH) and ATP:ADP. Such changes could conserve nitrogen by providing more carbon for amino acid biosynthesis and by blocking oxidative loss of the branched-chain amino acids. Consistent with this hypothesis, salmon fed carnitine (23 mmol/kg diet) for 9 wk exhibited greater metabolic rates than cohorts fed a carnitine-free diet (P < 0.05) for the following: 1) 1-[14C] palmitate oxidation by liver cubes (48%) and by isolated hepatocytes (151%), 2) pyruvate-dependent [14CO2]-fixation by isolated mitochondria (81%), 3) incorporation of 1-[14C] lactate into glucose by liver cubes (120%) and by isolated hepatocytes (210%), and 4) incorporation of [35S]-methionine into the acid-insoluble fraction of liver cubes (59%) and isolated hepatocytes (89%). Hepatic concentrations of seven amino acids, including the branched-chain amino acids, were greater (7–112%), as were the plasma concentrations of three of these (45–130%). However, 230% more enzyme in the mitochondria of carnitine-fed fish, and not a difference in the ratios of acetyl CoA:CoA-SH or ATP:ADP, appeared to account for accelerated flux through pyruvate carboxylase; flux through the dehydrogenase complex was unchanged. These results implicate induction of pyruvate carboxylase (or a reduction in turnover) and enhanced protein synthesis in the mechanism for carnitine-induced changes in gluconeogenesis and nitrogen metabolism.

Quercetin inhibits hepatotoxic effects by reducing trimethylamine-N-oxide formation in C57BL/6J mice fed with a high L-carnitine diet.

L-Carnitine can be metabolized to trimethylamine (TMA) by gut microbiota and further converted into trimethylamine N-oxide (TMAO) in the liver, leading to liver damage. This study aimed to investigate the protective effect of quercetin against high L-carnitine-induced liver toxicity in mice. 3% L-carnitine drinking water was used to feed mice in this study. The formation of TMAO in the blood circulation of the tested mice was down-regulated following quercetin treatment. Administration of quercetin could also effectively antagonize the liver injury caused by high L-carnitine intake, which was proved by the decreased serum AST and ALT activities and the reduced levels of inflammatory liver cytokines (IL-1, IL-6, TNF-α, and TNF-β). Moreover, quercetin exhibited a rebalancing effect on dyslipidemia (TC, TG, HDL, and LDL) and antioxidant abilities (SOD, GSH-Px, MDA, and RAHFR) in L-carnitine-treated mice. The results of hepatic H&E and Oil Red O staining further verified the liver injury of high L-carnitine-treated mice and the protective effects of quercetin. These findings suggested that quercetin could attenuate the hepatotoxic effects of the mice fed with a high L-carnitine diet via inhibiting the circulating TMAO formation.

Effects of dietary carnitine supplementation on semen output and quality of boars

Carnitine is an amino acid derivative that performs the functions of increasing energy production as well as acting as an antioxidant for sperm cells. This study was conducted to investigate the effects of the inclusion of carnitine in boar diets on semen output and quality. Sixty-four purebred and hybrid boars at a commercial boar stud were blocked by age and semen quality and randomly allotted to receive a daily 30 g top-dress of either soybean meal (CON) or soybean meal and 625 mg of L-Carnitine (CARN). Supplementation lasted for 12 weeks from May to July 2021 during which weekly semen collection was performed. Semen was evaluated in the stud for concentration and motility parameters using computer-assisted semen analysis (CASA). Samples were shipped to Purdue University for detailed morphology, viability, and CASA analysis performed in samples stored at 17 °C for 5 days. PROC Mixed (SAS v 9.4) was used to analyze data, with boar nested within treatment used in repeated measures analysis. Semen quality estimates from the week before supplementation were used as covariates in the statistical model. Tukey-Kramer adjustment was used for means separation. Carnitine supplementation had no effects on total sperm produced (P = 0.35). Percentage of motile sperm cells (P = 0.63), morphologically normal sperm (P = 0.42), viable sperm (P = 0.43), or sperm with normal acrosomes (P = 0.61) in the ejaculates were not different among treatments. Sperm kinematics in CARN ejaculates tended to have greater straight-line velocity and distance (P = 0.06 and P = 0.07, respectively). There were several interactions of treatment and day of storage for the kinematic parameters. However, these interactions do not show observable trends for CARN to improve or depress sperm function. Overall, the inclusion of 625 mg/d of carnitine in the diet of boars for 12 weeks had no effects on sperm output or quality with minor changes to sperm cell kinematics.

Changes of the liver metabolome following an intravenous lipopolysaccharide injection in Holstein cows supplemented with dietary carnitine

BackgroundCarnitine facilitates the flux of long-chain fatty acids for hepatic mitochondrial beta-oxidation, which acts to ameliorate the negative energy balance commonly affecting high-yielding dairy cows. Inflammation triggered by lipopolysaccharide (LPS) load can however pose a challenge to the metabolic integrity via the expression of pro-inflammatory mediators, leading to immune system activation and respective metabolic alterations. The effect of enhanced carnitine availability on hepatic metabolome profiles during an inflammatory challenge has not yet been determined in dairy cows. Herein, Holstein cows were supplemented with 25 g/d rumen-protected carnitine from 42 d prepartum until 126 d postpartum (n = 16) or assigned to the control group with no supplementation during the same period (n = 14). We biopsied the liver of the cows before (100 d postpartum) and after (112 d postpartum) an intravenous injection of 0.5 µg/kg LPS. Liver samples were subjected to a targeted metabolomics analysis using the AbsoluteIDQ p180 Kit (Biocrates Life Sciences AG, Innsbruck, Austria). ResultsMultivariate statistical analyses revealed that hepatic metabolome profiles changed in relation to both the carnitine supplementation and the LPS challenge. Comparing the metabolite profiles on 100 d, carnitine increased the concentration of short- and long-chain acyl-carnitines, which may be explained by an enhanced mitochondrial fatty acid shuttle and hence greater energy availability. The LPS injection affected hepatic metabolite profiles only in the carnitine supplemented group, particularly altering the concentration of biogenic amines.ConclusionsOur results point to interactions between an acute hepatic inflammatory response and biogenic amine metabolism, depending on energy availability.

Dietary Betaine and Carnitine Influence Metabolites and Immune Cell Response in Dogs

ObjectivesEvaluate the interaction of dietary betaine and carnitine on subsequent circulating metabolomics and immune cell response. MethodsThis study was a complete factorial with or without added betaine (276 and 5600 mg/kg as fed analyzed) and 2 levels of added dietary carnitine (26 and 382 mg/kg as fed analyzed). Thirty two dogs (range 2–11) were used. All dogs were assigned to one of the four treatment foods: control, control plus betaine, control plus carnitine and control plus betaine plus carnitine. All treatment foods were fed for ninety days. Blood analysis (metabolomics) and released cytokine concentrations were assessed at the beginning and at the end of the study. Whole blood was added and maintained in the TruCulture in vitro model using Null and LPS stimulated tubes. The supernatant, including circulating immune cells, was collected after incubation. The cytokines TNF-alpha, IL-6, IL-7, IL-8, MCP-1, IL-10, and IL-15 were measured using ELISA. The molar concentration of the sum of all the cytokines was the overall response variable. Statistical analysis of metabolomics was a repeated measure design using dietary betaine, carnitine, the presence of LPS in the culture medium, time on test, and their interactions as independent factors in the statistical model with P < 0.05 used as a cut off for significance. ResultsBetaine supplementation induced more significant biochemical perturbations in the plasma than carnitine alone and elicited a shift in the profiles of biochemicals involved in one-carbon metabolism. Carnitine supplementation influenced fatty acid oxidation signatures and possibly influenced gut microbiome metabolism as shown by increased indolelactate and indoleacetate. There was an interaction in the response of cytokines released to stimulation with LPS and dietary treatment such that the combination of dietary betaine and carnitine had the largest reduction in cytokine concentration after treatment without stimulation and the largest increase in cytokines in response to stimulation with LPS. ConclusionsDietary betaine influences the methyl donor pathway. Dietary carnitine influences fatty acid oxidation and the combination reduces inflammatory cytokine production in unstimulated cells while increasing cytokine production when cells are exposed to LPS. Funding SourcesThis study was funded by Hill’s Pet Nutrition, Inc.

Administration of 3,3-dimethyl-1-butanol is immunomodulatory in collagen induced arthritis murine model independent of TMA lyase activity

Abstract Studies of rheumatoid arthritis (RA) and murine collagen-induced arthritis (CIA) link the intestinal microbiome with disease and pathogenic autoantibodies. We have previously identified significant alterations in carnitine metabolism in mice with CIA, providing a potential link between bacterial dysbiosis and autoimmunity. Dietary carnitine is metabolized into trimethylamine (TMA) by bacterial enzyme TMA lyase which is oxidized in the host liver to TMAO. Prior studies determined that 3,3-dimethyl-1-butanol (DMB) and fluoromethylcarnitine (FMC) inhibit TMA lyase. Therefore, we tested if TMA lyase inhibition with DMB or FMC could ameliorate CIA. Male DBA1/j mice at 6 weeks of age were injected with bovine type II collagen in complete Freund’s adjuvant at days 0 and 21. On day 21 drinking water was replaced with vehicle, 1% vol/vol DMB, or 100mg/kg FMC. Mice were monitored for arthritis until day 35. DMB-treated mice had a significant (&amp;gt;50%) reduction in arthritis severity, as well as decreased anti-collagen antibodies, serum IFN-γ, and IL-17 compared to FMC and vehicle-treated mice with CIA. However, only FMC significantly reduced intestinal TMA and circulating TMAO, while DMB did not affect TMA/TMAO, suggesting that the effect of DMB is independent of TMA lyase inhibition. Using gas chromatography, we confirmed that DMB is absorbed and metabolized in mice, thereby identifying a novel metabolite, 3,3-dimethyl-1-butyric acid (DMBut). During CIA, 1% vol/vol DMBut significantly reduced disease, suggesting it is an active metabolite of DMB. Altogether our study suggests that DMB and/or its metabolites are immunomodulatory in CIA. Elucidating its target and mechanism of action may provide directions for RA therapeutic development. Supported by Grants from NIH (U01HL152405, T32AI074491) and from the State of Colorado Office of Economic Development and International Trade Advanced Industries Accelerator Program

PSIII-9 Effects of Dietary Carnitine Supplementation on Semen Output and Quality in Boars

Abstract Carnitine is an amino acid derivative with functions in increasing energy production as well as acting as an antioxidant for sperm cells. The objective of this study is to investigate the effects of the inclusion of carnitine in boar diets on sperm output and quality. Sixty-four boars at a commercial boar stud were blocked by age and semen quality and randomly allotted to receive a daily 30 g top-dress of either corn (CON) or corn and 625 mg of carnitine (CARN). Supplementation lasted for 12 weeks from May-July, 2021 during which weekly semen collection was performed. Semen was evaluated at the stud for concentration and motility parameters using computer-assisted semen analysis (CASA). Samples were also shipped to Purdue University for detailed morphology, viability, and CASA performed in samples stored at 17C for 5 d. PROC Mixed (SAS v 9.4) was used to evaluate the data where boar nested within treatment was used in repeated measures with the main effects of treatment and week and semen quality estimates from the week prior to supplementation as covariates in the model. Carnitine supplementation had no effects on total sperm produced (P = 0.35). Percentage of motile sperm cells (P = 0.38), morphologically normal sperm (P=0.42), viable sperm (P = 0.43), or sperm with normal acrosomes (P = 0.61) in the ejaculates was not different among treatments. Sperm kinematics in CARN ejaculates tended to have greater straight-line velocity and distance (P = 0.06 and P = 0.07, respectively). There were several interactions of treatment and day of storage for the kinematic parameters, however, these interactions do not show an observable trend for CARN to improve or depress sperm function. Overall, the inclusion of 625 mg/d of carnitine to the diet for 12 weeks had no effects on sperm output or quality with minor changes to sperm cell kinematics.

The microbial gbu gene cluster links cardiovascular disease risk associated with red meat consumption to microbiota L-carnitine catabolism.

The heightened cardiovascular disease (CVD) risk observed with omnivores is thought to be linked, in part, to gut microbiota-dependent generation trimethylamine-N-oxide (TMAO) from L-carnitine, a nutrient abundant in red meat. Gut microbial transformation of L-carnitine into trimethylamine (TMA), the precursor of TMAO, occurs via the intermediate γ-butyrobetaine (γBB). However, the relationship between γBB, red meat ingestion and CVD risks, as well as the gut microbial genes responsible for the transformation of γBB to TMA, are unclear. Here we show plasma γBB levels in individuals from a clinical cohort (n=2,918) are strongly associated with incident CVD event risks. Culture of human fecal samples and microbial transplantation studies in gnotobiotic mice with defined synthetic communities showed that the introduction of Emergencia timonensis, a human gut microbe that can metabolize γBB into TMA, is sufficient to complete the carnitine→γBB→TMA transformation, elevate TMAO levels, and enhance thrombosis potential in recipients following arterial injury. RNAseq analyses of E. timonensis identified a 6 gene cluster, herein named gamma-butyrobetaine utilization gene cluster (gbu), which is upregulated in response to γBB. Combinatorial cloning and functional studies identified 4 genes (gbuA, gbuB, gbuC, and gbuE) that are necessary and sufficient to recapitulate the conversion of γBB to TMA when co-expressed in E. coli. Finally, reanalysis of samples (n=113) from a clinical randomized diet intervention study showed that the abundance of fecal gbuA correlates with plasma TMAO and a red meat-rich diet. Our findings reveal a microbial gene cluster that is critical to dietary carnitine→γBB→TMA→TMAO transformation in hosts and contributes to CVD risk.

Proatherogenic gut-microbiome metabolite trimethylamine elicits a gut-liver circuit to regulate TMAO metabolism and atherosclerosis via mediation of CREBH

Abstract Introduction In humans, circulating metabolite Trimethylamine N-oxide (TMAO) is closely associated with higher risk of cardiovascular disease. Trimethylamine (TMA), a precursor of TMAO, is produced by gut microbiome using dietary components, i.e., choline and carnitine, as substrates. The gut-derived TMA is then transferred to the liver where it is further oxidized to TMAO by the flavin-containing monooxygenases (FMOs). The ER-resident transcription factor c-AMP responsive element binding protein H (CREBH/CREB3L3) is exclusively expressed in the liver and intestine. Perturbation of CREBH activity contributes to the development of hyperlipidemia and cardiovascular disease. Therefore, the Purpose of this study is to investigate the regulatory effect of a gut bacterium, Akkermansia muciniphila (A. muciniphila), on TMA and TMAO metabolism and the role of CREBH in this process. Methods Two groups of wild type (WT) and CREBH knockout (CREBH-KO) mice were inoculated with 200 μL of A. muciniphila (2×108 cfu/0.2 mL) in PBS or the vehicle (PBS) alone as control every other day through oral gavage for 2 weeks. Plasmas, liver and intestinal tissues were collected for metabolomics analysis, immunoblotting analysis and q-RT-PCR. Results Metabolomics analysis of the plasmas from the experimental mice revealed that increased colonization of A. muciniphila in the gut significantly reduced circulating TMA in the WT mice but not in CREBH-KO mice (P&amp;lt;0.05), suggesting that depletion of CREBH altered the microenvironment of gut microbiome which affected the metabolism of TMA by gut bacteria. In the livers, A. muciniphila treatment markedly reduced mRNA expression of FMO1 and FMO3 (P&amp;lt;0.05), which subsequently inhibited the enzymatic conversion of TMA to TMAO in hepatocytes. Immunoblotting analysis further revealed that LDL receptor was upregulated whereas ER stress markers, GRP94 and JNK1/2, were downregulated in the A. muciniphila treated KO mice, indicating an acceleration in lipoprotein (VLDL remnant) clearance from the circulation and the improvement of metabolic inflammation. In vitro, incubation of mouse hepatocytes AML12 with TMA (600 mM) for 12 hours stimulated expression of FMOs to facilitate the conversion of TMA to TMAO and induced lipotoxicity. Conclusion CREBH mediates the crosstalk between gut microbiome and liver metabolic system that regulates TMA and TMAO metabolism, which contributes to the induction of metabolic inflammation and atherogenesis. This novel finding may lend support to the therapeutic strategy of atherosclerosis. Funding Acknowledgement Type of funding sources: Foundation. Main funding source(s): British Heart Foundation

Increased plasma and milk short-chain acylcarnitine concentrations reflect systemic LPS response in mid-lactation dairy cows.

Lipopolysaccharides (LPS) challenge the metabolic integrity of high-yielding dairy cows, activating the immune system and altering energy metabolism. Fatty acid oxidation, a major energy-gaining pathway, can be improved by supplementary carnitine, facilitating the transport of fatty acids into mitochondria. The metabolic response to the LPS challenge could alter both the plasma and the milk metabolome. Plasma and milk samples collected from cows treated with (n = 27) or without (n = 27) dietary carnitine, before and after intravenous administration of LPS, were subjected to a targeted metabolomics analysis. Multivariate statistical analyses revealed that both plasma and milk metabolome changed in response to the LPS challenge in both the carnitine-supplemented and the control cows. Short-chain acylcarnitines (carbon chain length C2, C3, C4, and C5) and long-chain acylcarnitines (C14, C16, and C18) had the highest performance to indicate LPS response when testing the predictive power of single metabolites using receiver-operator characteristics (ROC) analysis. The maximum area under a ROC curve (AUC) was 0.93. Biogenic amines, including sarcosine, and amino acids such as glutamine and isoleucine had AUC > 0.80 indicating metabolic changes due to the LPS challenge. In summary, the metabolites involved in the LPS response were acylcarnitines C2 and C5, sarcosine, glutamine, and isoleucine in plasma, and acylcarnitines C4 and C5 in milk. The interrelationship of plasma and milk metabolome included correlation of acylcarnitines C2, C4, and C5 between plasma and milk.

Dietary factors, gut microbiota, and serum trimethylamine-N-oxide associated with cardiovascular disease in the Hispanic Community Health Study/Study of Latinos

Trimethylamine-N-oxide (TMAO), a diet-derived and gut microbiota-related metabolite, is associated with cardiovascular disease (CVD). However, major dietary determinants and specific gut bacterial taxa related to TMAO remain to be identified in humans. We aimed to identify dietary and gut microbial factors associated with circulating TMAO. This cross-sectional study included 3972 participants (57.3% women) aged 18-74 y from the Hispanic Community Health Study/Study of Latinos in the United States. Dietary information was collected by 24-h dietary recalls at baseline interview (2008-2011), and baseline serum TMAO and its precursors were measured by an untargeted approach. Gut microbiome was profiled by shotgun metagenomic sequencing in a subset of participants (n=626) during a follow-up visit (2016-2018). Logistic and linear regression were used to examine associations of inverse-normalized metabolites with prevalent CVD, dietary intake, and bacterial species, respectively, after adjustment for sociodemographic, behavioral, and clinical factors. TMAO was positively associated with prevalent CVD (case number=279; OR = 1.34; 95% CI: 1.17, 1.54, per 1-SD). Fish (P=1.26×10-17), red meat (P=3.33×10-16), and egg (P=3.89×10-5) intakes were top dietary factors positively associated with TMAO. We identified 9 gut bacterial species significantly associated with TMAO (false discovery rate <0.05). All 4 species positively associated with TMAO belong to the order Clostridiales, of which 3 might have homologous genes encoding carnitine monooxygenase, an enzyme converting carnitine to trimethylamine (TMA). The red meat-TMAO association was more pronounced in participants with higher abundances of these 4 species compared with those with lower abundance (Pinteraction=0.013), but such microbial modification was not observed for fish-TMAO or egg-TMAO associations. In US Hispanics/Latinos, fish, red meat, and egg intakes are major dietary factors associated with serum TMAO. The identified potential TMA-producing gut microbiota and microbial modification on the red meat-TMAO association support microbial TMA production from dietary carnitine, whereas the fish-TMAO association is independent of gut microbiota.

Dietary Carnitine and Carnosine Increase Body Lean in Healthy Cats in a Preliminary Study.

Simple SummaryCats, like mammals in general, experience lean body mass loss in later life. This study shows that two dietary interventions offset that loss: L-carnitine and carnosine. The combination did not change body lean. Interestingly, the combination resulted in an increased circulating concentration of 8 of the 10 cytokines measured, while L-carnitine alone resulted in decreased concentrations. Thus, L-carnitine could benefit the healthy cat while in some disease states it may be beneficial to increase both L-carnitine and carnosine.The need to maintain body lean as cats age is shown in both health and disease. In healthy cats, body lean is associated with enhanced movement and overall longevity. In many disease states (i.e., renal disease, obesity), an enhanced or minimally maximal support of body lean is associated with quality of life and is a nutritional goal in aiding in the management of the disease. This study was designed to investigate the effect of these two dietary components and their combination on body composition and circulating factors of health, including metabolomics analysis and cytokine concentration. The foods that were fed for 169 days to four groups of cats and consisted of control food (formulated to meet the nutritional needs of all adult cats), carnitine-enhanced food (control food plus 300 mg/kg L-carnitine), carnosine-enhanced food (control food plus 1000 mg/kg carnosine), and food enhanced with both (control plus 300 mg/kg carnitine and 1000 mg/kg carnosine). Dietary enhancement with L-carnitine and carnosine increased body lean at the end of the study compared to the cats consuming the control food or the combination food. The cats consuming L-carnitine alone had a decreased concentration of circulating cytokines, while those consuming the combination food had an increased concentration of glucose, pyruvate, succinate, and circulating cytokines.

Short and medium chain acylcarnitines as markers of outcome in diabetic and non-diabetic subjects with acute coronary syndromes

Abstract Background Dietary carnitine that is not absorbed can serve as a precursor for gut microbiota-dependent generation of trimethylamine N-oxide (TMAO), a pro-atherogenic and pro-thrombosis promoting metabolite. Gut microbiome-derived metabolites of dietary carnitine, including TMAO and g-butyrobetaine, may accelerate atherosclerosis, increase platelet reactivity and in vivo thrombosis. Carnitine metabolism also produces numerous molecular species of short, medium and long chain acylcarnitines, which play important roles in energy metabolism and intracellular fatty acid transport. Purpose We sought to evaluate the differences between diabetics and non-diabetics presenting with ACS with respect to acylcarnitines, and to explore their relationship with incident cardiovascular outcomes. Methods Using a large, prospectively recruited cohort of patients presenting to the cardiac cath lab with suspected acute coronary syndromes, we measured levels of plasma acylcarnitines, carnitine and its gut microbial-derived metabolites to assess their relationship with independently adjudicated major adverse cardiac events (MACE = myocardial infarction, stroke or TIA, need for revascularization or all-cause mortality) amongst diabetics and non-diabetics. Results We analysed 1683 patients who presented with ACS, were treated according to current guidelines and had undergone acylcarnitine analysis. There were 294 diabetics and 1389 non-diabetics. Diabetics had significantly higher plasma levels of all acyl carnitine metabolites than non-diabetics (P&amp;lt;0.001), but not of carnitine itself. Baseline plasma levels of all gut microbiome derived carnitine metabolites (TMAO, g-butyrobetaine and crotonobetaine) were also significantly higher in those who subsequently experienced a MACE. All carnitine metabolites, apart from octenoylcarnitine, were significantly associated with MACE on univariate analysis, while acetylcarnitine and crotonobetaine were independently associated with MACE after multivariate adjustment. Conclusion Serum short- and medium- chain acylcarnitine levels are significantly higher in diabetic patients presenting with ACS and predict MACE. After multivariate adjustment, acetylcarnitine and crotonobetaine remained an independent predictor of MACE. Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): Zurich Heart House - Foundation for Cardiovascular Research

Preventive Role of L-Carnitine and Balanced Diet in Alzheimer's Disease.

The prevention or alleviation of neurodegenerative diseases, including Alzheimer’s disease (AD), is a challenge for contemporary health services. The aim of this study was to review the literature on the prevention or alleviation of AD by introducing an appropriate carnitine-rich diet, dietary carnitine supplements and the MIND (Mediterranean-DASH Intervention for Neurodegenerative Delay) diet, which contains elements of the Mediterranean diet and the Dietary Approaches to Stop Hypertension (DASH) diet. L-carnitine (LC) plays a crucial role in the energetic metabolism of the cell. A properly balanced diet contains a substantial amount of LC as well as essential amino acids and microelements taking part in endogenous carnitine synthesis. In healthy people, carnitine biosynthesis is sufficient to prevent the symptoms of carnitine deficiency. In persons with dysfunction of mitochondria, e.g., with AD connected with extensive degeneration of the brain structures, there are often serious disturbances in the functioning of the whole organism. The Mediterranean diet is characterized by a high consumption of fruits and vegetables, cereals, nuts, olive oil, and seeds as the major source of fats, moderate consumption of fish and poultry, low to moderate consumption of dairy products and alcohol, and low intake of red and processed meat. The introduction of foodstuffs rich in carnitine and the MIND diet or carnitine supplementation of the AD patients may improve their functioning in everyday life.

Growth Performance, Biochemical Indices and Antioxidant Status of Grey Mullet (Mugil cephalus Linnaeus, 1758) Under Dietary L-Carnitine Supplementation

The present research evaluated the use of dietary carnitine supplementation and its effects on the growth, body composition, fatty acids, biochemical parameters, Insulin-like growth factor 1 (IGF-1) level and antioxidant activity, in grey mullet. Four experimental diets were prepared by adding carnitine at concentrations of 0, 400, 800, and 1200 mg kg−1 diet (C0, C400, C800 and C1200 respectively). After 9 weeks of the feeding trial, a significant increase in growth performance (except for Daily Growth Rate or DGR), carcass quality (crude protein and crude lipid), biochemical parameters (cholesterol, triglyceride, total lipid, free fatty acid or FFA, total protein, albumin, and globulin), plasma superoxide dismutase and glutathione peroxidase activities was detected in the fish fed on C800 diet, as compared to those fed on the other diets (P 0.05) differences were observed in moisture and crude ash contents among groups. Barring the C1200 diet, there was also a positive correlation between the plasma IGF-1 level and DGR. The results showed that the diet containing 800 mg kg−1 L-carnitine enhanced growth yield, feed utilization, and carcass quality; as well as biochemical and antioxidant activity of grey mullet. The authors concluded that the maximum recommended levels of L-carnitine in diets for grey mullet (Mugil cephalus) can be established at 800 mg kg−1.

Cats increase lean body mass with carnitine or carnosine but not with the combination

This study evaluated whether dietary carnitine or carnosine would change lean body mass, circulating cytokines or metabolites in cats. All study protocols were reviewed and approved by the Institutional Animal Care and Use Committee, Hill's Pet Nutrition, Inc., Topeka, KS. Forty four pets were assigned into four groups: Group 1 (n=11) was fed the control diet, group 2 (n=11) was fed the control diet + L‐carnitine (0.03%), group 3 (n=12) was fed the control diet + L‐carnosine (0.1%), and Group 4 (n=10) was fed the Control diet + L‐carnitine + L‐carnosine. The ages of the cats ranged from 7.2 to 13.9 yr. The duration of the study was 6 months. Initial body composition, cytokines and metabolomics profiles were compared to final and changes were compared across treatments. Metabolomics were measured by Metabolon (Morrisville, NC), cytokines were measured by ELISA. Change in lean body mass (LBM) was assessed by Dual‐energy X‐ray absorptiometry (DEXA) and reported in cats as the difference in LBM between initial and final times. Changes in analytes were then compared amongst the 4 groups. Serum levels of cytokines assessed included Flt‐3L, IFN‐γ, IL12p40, IL‐4, IL‐6, IL‐8, IL‐13, IL‐18, and MCP‐1. Modest reductions were observed in the levels of selected cytokines on day 169 when compared to the baseline but these changes were not significant between groups. Lean body mass results showed that cats fed either carnitine alone (+106 g) or carnosine alone (+96 g) had increased lean when compared to control cats or cats supplemented with both carnitine and carnosine (p&lt;0.01). There was no statistical difference between treatments in either body weight or body fat change. Carnitine and deoxycarnitine were increased in the group that had carnitine alone (p&lt;0.05) while many acyl carnitines were increased in both groups supplemented with carnitine. Carnosine was not changed but beta‐alanine was increased in cats fed carnosine. The metabolism of aromatic amino acids (phenylalanine, tyrosine, and tryptophan and dietary polyphenolic compounds) occurs, in part, through the involvement of enzymes encoded within the microbiome. Several microbiota‐derived‐metabolites were higher in Groups 2, 3, and 4 when compared to Group 1 at various time points. These data indicate that supplementation of carnitine or carnosine is beneficial in increasing LBM in felines but that when combined they do not influence LBM.Support or Funding InformationThis study was funded by Hill's Pet Nutrition Inc.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Clinical Research and Therapeutic Importance of Dietary Supplement L-Carnitine: Review

Carnitine, derived from an amino acid, is found in nearly all cells of the body. Its name is derived from the Latin carnus or flesh, as the compound was isolated from meat. Carnitine is the generic term for a number of compounds that include L-carnitine, acetyl-L-carnitine, and propionyl-L-carnitine. Carnitine plays a critical role in energy production. It transports long-chain fatty acids into the mitochondria so they can be oxidized to produce energy. It also transports the toxic compounds generated out of this cellular organelle to prevent their accumulation. Given these key functions, carnitine is concentrated in tissues like skeletal and cardiac muscle that utilize fatty acids as a dietary fuel. The body makes sufficient carnitine to meet the needs of most people. For genetic or medical reasons, some individuals (such as preterm infants), cannot make enough, so for them carnitine is a conditionally essential nutrient. Animal products like meat, fish, poultry, and milk are the best sources. In general, the redder the meat, the higher its carnitine content. Dairy products contain carnitine primarily in the whey fraction. Adults eating mixed diets that include red meat and other animal products obtain about 60–180 milligrams of carnitine per day. Vegans get considerably less (about 10–12 milligrams) since they avoid animal derived foods. Most (54–86%) dietary carnitine is absorbed in the small intestine and enters the bloodstream. L-carnitin proved its medicinal importance but in the present era it is neglected. In this review I am trying to explain therapeutic importance of L-carnitin.

Enterobacter aerogenes ZDY01 Attenuates Choline-Induced Trimethylamine N-Oxide Levels by Remodeling Gut Microbiota in Mice.

Trimethylamine N-oxide (TMAO), which is transformed from trimethylamine (TMA) through hepatic flavin-containing monooxygenases, can promote atherosclerosis. TMA is produced from dietary carnitine, phosphatidylcholine, and choline via the gut microbes. Previous works have shown that some small molecules, such as allicin, resveratrol, and 3,3-dimethyl-1-butanol, are used to reduce circulating TMAO levels. However, the use of bacteria as an effective therapy to reduce TMAO levels has not been reported. In the present study, 82 isolates were screened from healthy Chinese fecal samples on a basal salt medium supplemented with TMA as the sole carbon source. The isolates belonged to the family Enterobacteriaceae, particularly to genera Klebsiella, Escherichia, Cronobacter, and Enterobacter. Serum TMAO and cecal TMA levels were significantly decreased in choline-fed mice treated with Enterobacter aerogenes ZDY01 compared with those in choline-fed mice treated with phosphate-buffered saline. The proportions of Bacteroidales family S24-7 were significantly increased, whereas the proportions of Helicobacteraceae and Prevotellaceae were significantly decreased through the administration of E. aerogenes ZDY01. Results indicated that the use of probiotics to act directly on the TMA in the gut might be an alternative approach to reduce serum TMAO levels and to prevent the development of atherosclerosis and "fish odor syndrome" through the effect of TMA on the gut microbiota.

L-Carnitine improves gastrointestinal disorders and altered the intestinal microbiota in hemodialysis patients.

Patients receiving hemodialysis also manifest gastrointestinal symptoms, such as constipation, caused by restriction of water intake and the loss of body water balance. Because dietary carnitine deficiency is considered to cause smooth muscle dysmotility of the gastrointestinal tract similarly to that in skeletal muscles, carnitine deficiency in hemodialysis patients may be one cause of gastrointestinal discomfort and dysfunctions. We performed a multicenter nonrandomized single-arm prospective clinical trial. Fifteen Japanese patients receiving hemodialysis were administered L-carnitine tablets (900 mg) for 3 months, and clinical and biochemical analyses were performed before and after treatment. The serum total carnitine level was increased significantly by supplementation with L-carnitine for 3 months (from 40.9 ± 2.6 μmol/l to 172.3 ± 19.0 μmol/l, p<0.05). The myasthenia score was decreased significantly by the supplementation (from 1.3 ± 0.3 to 0.8 ± 0.2, p<0.05). The frequency of passing stool tended to increase with the treatment for 3 months (from 4.2 ± 0.5 times/week to 4.8 ± 0.5 times/week). A phyla-level analysis of the microbiota showed that the composition of the individual microbiota was not different between before and after supplementation. A genus-level analysis, however, revealed that the relative abundance of genus Clostridium subcluster 4 was significantly decreased by the supplementation (from 7.7 ± 1.9% to 4.7 ± 1.3%, p<0.05). Oral supplementation of L-carnitine to the patients receiving hemodialysis improved not only their muscle discomfort but also their gastrointestinal disorders and microbiota, although its effect on the prognosis of hemodialysis patients should be further investigated.