L-carnitine supplementation for muscle weakness and fatigue in children with neurofibromatosis type 1: A Phase 2a clinical trial.

Reduced muscle tone, muscle weakness, and physical fatigue can impact considerably on quality of life for children with neurofibromatosis type 1 (NF1). Human muscle biopsies and mouse models of NF1 deficiency in muscle show intramyocellular lipid accumulation, and preclinical data have indicated that L-carnitine supplementation can ameliorate this phenotype. The aim of this study is to examine whether daily L-carnitine supplementation is safe and feasible, and will improve muscle strength and reduce fatigue in children with NF1. A 12-week Phase 2a trial was conducted using 1000 mg daily oral levocarnitine tartrate supplementation. Recruited children were between 8 and 12 years old with a clinical diagnosis of NF1, history of muscle weakness and fatigue, and naïve to L-carnitine. Primary outcomes were safety (self-reporting, biochemical testing) and compliance. Secondary outcomes included plasma acylcarnitine profiles, functional measures (muscle strength, long jump, handwriting speed, 6-minute-walk test [6MWT]), and parent-reported questionnaires (PedsQL™, CBCL/6-18). Six children completed the trial with no self-reported adverse events. Biochemical tests for kidney and liver function were normal, and the average compliance was 95%. Plasma acylcarnitine levels were low, but within a range not clinically linked to carnitine deficiency. For strength measures, there was a mean 53% increase in dorsiflexion strength (95% confidence interval [CI] 8.89-60.75; p = 0.02) and mean 66% increase in plantarflexion strength (95% CI 12.99-134.1; p = 0.03). In terms of muscle performance, there was a mean 10% increase in long jump distance (95% CI 2.97-16.03; p = 0.01) and 6MWT distance (95% CI 5.88-75.45; p = 0.03). Comparison with the 1000 Norms Project data showed a significant improvement in Z-score for all of these measures. Parent reports showed no negative impact on quality of life, and the perceived benefits led to the majority of individuals remaining on L-carnitine after the study. Twelve weeks of L-carnitine supplementation is safe and feasible in children with NF1, and a Phase 3 trial should confirm the efficacy of treatment.

Carnitine insufficiency is associated with fatigue during lenvatinib treatment in patients with hepatocellular carcinoma.

BACKGROUND: Fatigue is a common adverse event during lenvatinib treatment in patients with hepatocellular carcinoma. One mechanism contributing to development of fatigue might involve abnormal adenosine triphosphate synthesis that is caused by carnitine deficiency. To address this possibility, we examined the relationship between carnitine levels and fatigue during lenvatinib treatment. METHODS: This prospective study evaluated 20 patients with hepatocellular carcinoma who underwent lenvatinib treatment. Both blood and urine samples were collected from the patients before starting lenvatinib therapy (day 0), and on days 3, 7, 14, and 28 thereafter. Plasma and urine concentrations of free and acyl carnitine (AC) were assessed at each time point. The changes in daily fatigue were evaluated using the Brief Fatigue Inventory (BFI). RESULTS: Plasma levels of free carnitine (FC) at days 3 and 7 were significantly higher compared with baseline (p = 0.005, p = 0.005, respectively). The urine FC level at day 3 was significantly higher compared with baseline (p = 0.030) and that of day 7 tended to be higher compared with baseline (p = 0.057). The plasma AC concentration at days 14 and 28 was significantly higher compared with that of baseline (p = 0.002, p = 0.005, respectively). The plasma AC-to-FC (AC/FC) ratio on days 14 and 28 was significantly higher compared with baseline (p = 0.001, p = 0.003, respectively). There were significant correlations between the plasma AC/FC ratio and the change in the BFI score at days 14 and 28 (r = 0.461, p = 0.041; r = 0.770, p = 0.002, respectively). CONCLUSIONS: Longitudinal assessments of carnitine and fatigue in patients with hepatocellular carcinoma suggest that lenvatinib affects the carnitine system in patients undergoing lenvatinib therapy and that carnitine insufficiency increases fatigue. The occurrence of carnitine insufficiency may be a common cause of fatigue during the treatment.

Evaluation of dietary treatment and amino acid supplementation in organic acidurias and urea-cycle disorders: On the basis of information from a European multicenter registry.

Organic acidurias (OAD) and urea-cycle disorders (UCD) are rare inherited disorders affecting amino acid and protein metabolism. As dietary practice varies widely, we assessed their long-term prescribed dietary treatment against published guideline and studied plasma amino acids levels. We analyzed data from the first visit recorded in the European registry and network for intoxication type metabolic diseases (E-IMD, Chafea no. 2010 12 01). In total, 271 methylmalonic aciduria (MMA) and propionic aciduria (PA) and 361 UCD patients were included. Median natural protein prescription was consistent with the recommended daily allowance (RDA), plasma L-valine (57%), and L-isoleucine (55%) levels in MMA and PA lay below reference ranges. Plasma levels were particularly low in patients who received amino acid mixtures (AAMs-OAD) and L-isoleucine:L-leucine:L-valine (BCAA) ratio was 1.0:3.0:3.2. In UCD patients, plasma L-valine, L-isoleucine, and L-leucine levels lay below reference ranges in 18%, 30%, and 31%, respectively. In symptomatic UCD patients who received AAM-UCD, the median natural protein prescription lay below RDA, while their L-valine and L-isoleucine levels and plasma BCAA ratios were comparable to those in patients who did not receive AAM-UCD. Notably, in patients with ornithine transcarbamylase syndrome (OTC-D), carbamylphosphate synthetase 1 syndrome (CPS1-D) and hyperammonemia-hyperornithinemia-homocitrullinemia (HHH) syndrome selective L-citrulline supplementation resulted in higher plasma L-arginine levels than selective L-arginine supplementation. In conclusion, while MMA and PA patients who received AAMs-OAD had very low BCAA levels and disturbed plasma BCAA ratios, AAMs-UCD seemed to help UCD patients obtain normal BCAA levels. In patients with OTC-D, CPS1-D, and HHH syndrome, selective L-citrulline seemed preferable to selective L-arginine supplementation.

A systematic review about prophylactic L-carnitine administration in parenteral nutrition of extremely preterm infants.

OBJECTIVE: Preterm infants with total parenteral nutrition are at particular risk of developing carnitine deficiency with impaired tolerance of parenteral lipids. The  objective was to review the scientific literature on potencial benefits of  prophylactic L-carnitine administration in parenteral nutrition of preterm  newborns. METHODS: Selected scientific articles in MEDLINE/PubMed, Scopus, The Cochrane Library, British Library EThOS and TESEO databases were assessed for this  systematic review. The terms used as descriptors were «Total Parenteral  Nutrition¼ and «Carnitine¼. Jadad scale was chosen to evaluate the quality of  them. RESULTS: 18 out of the 93 references retrieved were selected for reviewing after  applying the inclusion and exclusion criteria, 4 of them were discarded for being  considered of low quality. Almost all studies agreed on the analytical variables  measured (free carnitine and acylcarnitine, triglycerides, free fatty acids and  ketone bodies). Other clinical variables such as weight gain, apnea, or lenght of  stay at hospital were also considered. CONCLUSIONS: The present results prove that routine supplementation in the  parenteral nutrition of preterm newborns may help to increase carnitine levels,  but neither a relevant improvement in the lipid profile, or an increase in weight  gain, or a decrease in morbimortality or reduction of hospital stay could be  demonstrated. More studies are needed in preterm infants to know whether  routine supplementation of L-carnitine in neonates requiring total parenteral  nutrition for a long time would provide any clinical benefit.

Objetivo: Los recién nacidos pretérmino con nutrición parenteral total tienen tanto una reducción de la ingesta de L-carnitina como de las reservas tisulares, lo que podría suponer una peor tolerancia de los lípidos  parenterales. El objetivo fue revisar la literatura científica en busca de los  posibles beneficios clínicos de su administración en la nutrición parenteral.Métodos: Revisión sistemática de los documentos recuperados en las bases de  datos MEDLINE/Pubmed, Scopus, The Cochrane Library, British Library EThOS y  TESEO. Los términos utilizados como descriptores fueron «Total Parenteral  Nutrition¼ y «Carnitine¼. La calidad de los artículos se evaluó mediante la escala de Jadad.Resultados: Tras aplicar los criterios de inclusión y exclusión, se seleccionaron para la revisión 18 artículos de las 93 referencias recuperadas, de  los cuales 4 fueron descartados al no ser considerados de alta calidad. Casi la  totalidad de los estudios coincidían en las variables analíticas medidas (carnitina  libre y acilcarnitina, triglicéridos, ácidos grasos libres y cuerpos cetónicos).  Además, en algunos se tenían en cuenta otras variables clínicas, como la  ganancia ponderal o la apnea.Conclusiones: La suplementación rutinaria en la nutrición parenteral de recién  nacidos pretérmino sí parece mejorar los niveles plasmáticos de carnitina, pero  sin llegar a demostrar una mejoría significativa en el perfil lipídico, ni aumento  de la ganancia ponderal, ni disminución de la morbimortalidad o reducción de la  estancia hospitalaria. Son necesarios más estudios para demostrar si la  suplementación sistemática a recién nacidos pretérmino que requieren nutrición  parenteral total durante más de un mes aportaría beneficios clínicos.

Medium-chain triglycerides supplement therapy with a low-carbohydrate formula can supply energy and enhance ammonia detoxification in the hepatocytes of patients with adult-onset type II citrullinemia.

Citrin, encoded by SLC25A13, constitutes the malate-aspartate shuttle, the main NADH-shuttle in the liver. Citrin deficiency causes neonatal intrahepatic cholestasis (NICCD) and adult-onset type II citrullinemia (CTLN2). Citrin deficiency is predicted to impair hepatic glycolysis and de novo lipogenesis, resulting in hepatic energy deficit. Secondary decrease in hepatic argininosuccinate synthetase (ASS1) expression has been considered a cause of hyperammonemia in CTLN2. We previously reported that medium-chain triglyceride (MCT) supplement therapy with a low-carbohydrate formula was effective in CTLN2 to prevent a relapse of hyperammonemic encephalopathy. We present the therapy for six CTLN2 patients. All the patients' general condition steadily improved and five patients with hyperammonemic encephalopathy recovered from unconsciousness in a few days. Before the treatment, plasma glutamine levels did not increase over the normal range and rather decreased to lower than the normal range in some patients. The treatment promptly decreased the blood ammonia level, which was accompanied by a decrease in plasma citrulline levels and an increase in plasma glutamine levels. These findings indicated that hyperammonemia was not only caused by the impairment of ureagenesis at ASS1 step, but was also associated with an impairment of glutamine synthetase (GS) ammonia-detoxification system in the hepatocytes. There was no decrease in the GS expressing hepatocytes. MCT supplement with a low-carbohydrate formula can supply the energy and/or substrates for ASS1 and GS, and enhance ammonia detoxification in hepatocytes. Histological improvement in the hepatic steatosis and ASS1-expression was also observed in a patient after long-term treatment.

Hyperammonaemic encephalopathy following an uncomplicated surgery.

A 59-year-old woman who underwent an uncomplicated exploratory laparotomy, adhesiolysis, small bowel resection and anterolateral thigh flap had a complicated postoperative period characterised by wound dehiscence and poor nutritional intake. 29 days postoperatively, a tremor developed in her upper limbs associated with weakness. Her Glasgow Coma Scale (GCS) fell to 4 and she was transferred to the intensive care unit. The patient was reviewed by multiple specialists and multiple differentials were considered and eliminated. Eventually, investigations revealed hyperammonaemic encephalopathy, being a result of low arginine and potentially small intestinal bacterial overgrowth. Following treatment with sodium benzoate, sodium phenylbutyrate and arginine along with haemodialysis and rifaximin, GCS and hyperammonaemia rapidly improved. She was stepped down to surgical high-dependency unit, continued arginine therapy with total parenteral nutrition and percutaneous endoscopic gastrostomy feeds. She was discharged with regular follow-up from surgeons and biochemistry and continues oral arginine therapy.

Primary Carnitine Deficiency and Newborn Screening for Disorders of the Carnitine Cycle.

Carnitine is needed for transfer of long-chain fatty acids across the inner mitochondrial membrane for subsequent ß-oxidation. Carnitine can be synthesized by the body and is also obtained in the diet through consumption of meat and dairy products. Defects in carnitine transport such as those caused by defective activity of the OCTN2 transporter encoded by the SLC22A5 gene result in primary carnitine deficiency, and newborn screening programmes can identify patients at risk for this condition before irreversible damage. Initial biochemical diagnosis can be confirmed through molecular testing, although direct study of carnitine transport in fibroblasts is very useful to confirm or exclude primary carnitine deficiency in individuals with genetic variations of unknown clinical significance or who continue to have low levels of carnitine despite negative molecular analyses. Genetic defects in carnitine biosynthesis do not generally result in low plasma levels of carnitine. However, deletion of the trimethyllysine hydroxylase gene, a key gene in carnitine biosynthesis, has been associated with non-dysmorphic autism. Thus, new roles for carnitine are emerging that are unrelated to classic inborn errors of metabolism.

Round Table Discussion.

The 1st International Carnitine Working Group concluded with a round table discussion addressing several areas of relevance. These included the design of future studies that could increase the amount of evidence-based data about the role of carnitine in the treatment of fatty acid oxidation defects, for which substantial controversy still exists. There was general consensus that future trials on the effect of carnitine in disorders of fatty acid oxidation should be randomized, double-blinded, multicentered and minimally include the following diagnoses: medium-chain acyl coenzyme A (CoA) dehydrogenase deficiency, very long-chain acyl-CoA dehydrogenase deficiency, long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency and mitochondrial trifunctional protein deficiency. Another area that generated interest was trials of carnitine in cardiomyopathy and, especially, the use of biomarkers to identify patients at greater risk of cardiotoxicity following treatment with anthracyclines. The possibility that carnitine treatment may lead to improvements in autistic behaviors was also discussed, although the evidence is still not sufficient to make any firm conclusions in this regard. Preliminary data on carnitine levels in children and adolescents with primary hypertension, low birth weight and nephrotic syndrome was also presented. Lastly, the panelists stressed that there remains an objective need to harmonize the terminology used to describe carnitine deficiencies (e.g., primary, secondary and systemic deficiency).

Historical Perspective on Clinical Trials of Carnitine in Children and Adults.

The metabolic roles of carnitine have been greatly clarified over the past 50 years, and it is now well established that carnitine is a key player in mitochondrial generation of energy and metabolism of acetyl coenzyme A. A therapeutic role for carnitine in treatment of nutritional deficiencies in infants and children was first demonstrated in 1958, and since that time it has been used to treat a number of inborn errors of metabolism. Carnitine was approved by the US Food and Drug Administration in 1985 for treatment of 'primary carnitine deficiency', and later in 1992 for treatment of 'secondary carnitine deficiency', a definition that included the majority of relevant metabolic disorders associated with low or abnormal plasma carnitine levels. Today, carnitine treatment of inborn errors of metabolism is a safe and integral part of many treatment protocols, and a growing interest in carnitine has resulted in greater recognition of many causes of carnitine depletion. Notwithstanding, there is still a lack of data from randomized clinical trials, even on the use of carnitine in inborn errors of metabolism, although ethical issues may be a contributing factor in this regard.

Veterinary clinical nutrition: success stories: an overview.

In this overview of success stories in veterinary clinical nutrition topics in cats and dogs reviewed include the dietary management of chronic kidney disease, dissolution of urinary tract uroliths by dietary modification, the recognition that taurine and L-carnitine deficiencies can cause dilated cardiomyopathy; that clinical signs associated with feline hyperthyroidism (caused by a benign adenoma) can be controlled by a low-iodine diet alone; that dietary management of canine osteoarthritis can also reduce non-steroidal anti-inflammatory drug doses; and that disease-free intervals and survival times can be statistically longer in dogs with Stage III lymphoma managed with diet. As we discover more about nutrigenetics and nutrigenomics, and as we expand our basic understanding of idiopathic diseases we are bound to identify more nutritionally related causes, and be able to develop novel dietary strategies to manage disease processes, including the formulation of diets designed to alter gene expression to obtain beneficial clinical outcomes.

Carnitine deficiency: Risk factors and incidence in children with epilepsy.

BACKGROUND: Carnitine deficiency is relatively common in epilepsy; risk factors reportedly include combination antiepileptic drug (AED) therapy with valproic acid (VPA), young age, intellectual disability, diet and enteral or parenteral feeding. Few studies have examined the correlation between each risk factor and carnitine deficiency in children with epilepsy. We examined the influence of these risk factors on carnitine deficiency, and identified a formula to estimate plasma free carnitine concentration in children with epilepsy. METHODS: Sixty-five children with epilepsy and 26 age-matched controls were enrolled. Plasma carnitine concentrations were measured using an enzyme cycling assay, and correlations were sought with patients' other clinical characteristics. RESULTS: Carnitine deficiency was found in approximately 17% of patients with epilepsy and was significantly associated with carnitine-free enteral formula only by tube feeding, number of AEDs taken (independent of VPA use), body weight (BW), body height and Gross Motor Function Classification System (GMFCS) score. Stepwise multiple linear regression analysis indicated that carnitine concentration (in µmol/L) could be accurately estimated from a formula that does not require blood testing: 42.44+0.14×(BW in kg)-18.16×(feeding)-3.19×(number of AEDs), where feeding was allocated a score of 1 for carnitine-free enteral formula only by tube feeding and 0 for taking food orally (R(2)=0.504, P<0.001). CONCLUSIONS: Carnitine-free enteral formula only by tube feeding, multiple AED treatment and low BW are risk factors for carnitine deficiency in children with epilepsy. l-carnitine should be administered to children at risk of deficiency to avoid complications. Treatment decisions can be informed using an estimation formula that does not require blood tests.

[Hyperammonemic encephalopathy: nutritional assessment and management of a case]. / Encefalopatía hiperamoniémica: valoración y manejo nutricional a propósito de un caso.

OTC deficiency is a disorder of the urea cycle X-linked. It is manifested in men as severe hyperammonemia in the first days of life. In women the disease is milder severity. Various conditions cause decompensation with hyperammonemia. It could be fatal or cause permanent neurological damage. We report a 36 years old woman admitted for surgery, she suffered a decompensation in conjunction with surgical wound infection. Hyperammonemia caused neurological deterioration with decreased level of consciousness, tetraparesis and neurogenic dysphagia. The treatment consisting of low-protein diet, ammonium chelating drugs and dialytic measures, was effective in controlling hyperammonaemia and improving neurological status. This case illustrates the importance of nutritional support of patients with disorders of the urea cycle in the hospital because the descompensations are more frecuent here.

A long-term survival case of arginase deficiency with severe multicystic white matter and compound mutations.

Neuropathology and neuroimaging of long-term survival cases of arginase deficiency are rarely reported. The magnetic resonance imaging (MRI) of our case showed severe multicystic white matter lesions with cortical atrophy, which were more severe compared with previous reports. In this patient, low-protein diet successfully reduced hyperammonemia, but hyperargininemia persisted. These severe neurological and MRI findings may be explained by a compound heterozygote, inheriting both of severe mutant alleles from her parents.

Conventional diet therapy for hyperammonemia is risky in the treatment of hepatic encephalopathy associated with citrin deficiency.

Citrin deficiency caused by SLC25A13 gene mutations develops into adult-onset type II citrullinemia (CTLN2) presenting with hepatic encephalopathy. Recent studies have suggested that excessive loading of carbohydrates is harmful in citrin-deficient individuals. Here we report a CTLN2 patient who showed further deterioration of encephalopathy after the employment of conventional low-protein diet therapy for chronic liver failure. Owing to the high carbohydrate content, the conventional low-protein diet therapy should be avoided in patients with hepatic encephalopathy associated with citrin deficiency. In addition, our observation may suggest that carbohydrate-restricted diet in which the content of carbohydrate is below 50% of daily energy intake can have therapeutic efficacy in CTLN2 patients.

Nutritional management of patients with urea cycle disorders.

The nutritional management of patients with urea cycle disorders (UCDs) involves restriction of dietary protein along with provision of adequate protein-free energy, essential amino acid supplements, and vitamins and minerals in combination with nitrogen-scavenging drugs. The present paper discusses nutrition therapy for a range of circumstances: during an acute hyperammonaemic episode and at hospital discharge; before, during, and after surgery; and for lifelong chronic management of UCDs.