Carnitine is necessary for transport of long-chain fatty acids into mitochondria, to enter the beta-oxidation cycle. Four carnitine cycle defects have been described. The carnitine transporter mediates carnitine transport across the plasma membrane. Symptoms include hypoketotic hypoglycaemia and cardiomyopathy. Some affected subjects are asymptomatic. Newborn screening detects very low levels of free carnitine in some but not all. Carnitine palmitoyltransferase type IA (CPTI) transports long-chain fatty acyl-CoAs across the outer mitochondrial membrane. Affected infants have hypoketotic hypoglycaemia with catabolic stress, but otherwise remain well. Newborn screening tests reveal elevated free carnitine, (elevated C0/C16+C18). Sensitivity is unclear and confirmation needs leukocyte or fibroblast assays. Carnitine-acylcarnitine translocase transfers fatty acylcarnitines across the inner mitochondrial membrane. The most common presentation is sudden death in the first days. Carnitine palmitoyltransferase type II (CPTII) converts long-chain acylcarnitines to long-chain acylCoAs for beta-oxidation. Severe deficiency is lethal. Newborn screening for both disorders reveals elevated palmitoylcarnitine and enzymology or mutation analysis is needed for diagnosis. Late-onset CPTII is the most common disorder, presenting as muscle pain and rhabdomyolysis on severe exercise. All 4 disorders can be detected by newborn screening, with variable sensitivity. Late-onset CPTII probably cannot be detected. Carnitine transporter, CPTI and late-onset CPTII have proven treatment strategies.
Carnitine ; metabolism ; Carnitine O-Palmitoyltransferase ; deficiency ; Humans ; Infant, Newborn ; Metabolism, Inborn Errors ; diagnosis ; enzymology ; Neonatal Screening

This study aimed to identify the type of carnitine palmitoyltransferase 2 (CPT2) gene mutation in the child with carnitine palmitoyltransferase II (CPT II) deficiency and her parents and to provide the genetic counseling and prenatal diagnosis for the family members. As the proband, a 3-month-old female baby was admitted to the hospital due to fever which had lasted for 8 hours. Tandem mass spectrometric analysis for blood showed an elevated plasma level of acylcarnitine, which suggested CPT II deficiency. The genomic DNA was extracted from peripheral blood of the patient and her parents. Five exon coding regions and some intron regions at the exon/intron boundaries of the CPT2 gene were analyzed by PCR and Sanger sequencing. Amniotic fluid was taken from the mother during the second trimester, and DNA was extracted to analyze the type of CPT2 gene mutation. Sanger sequencing results showed that two mutations were identified in the CPT2 gene of the proband: c.886C>T (p.R296X) and c.1148T>A (p.F383Y), which were inherited from the parents; the second child of the mother inherited the mutation of c.886C>T (p.R296X) and showed normal acylcarnitine spectrum and normal development after birth. It is concluded that the analysis of CPT2 gene mutations in the family suggested that the proband died of CPT II deficiency and that the identification of the mutations was helpful in prenatal diagnosis in the second pregnancy.
Carnitine O-Palmitoyltransferase ; deficiency ; genetics ; Female ; Humans ; Infant ; Metabolism, Inborn Errors ; diagnosis ; genetics ; Mutation ; Prenatal Diagnosis

OBJECTIVE: To report on the clinical, metabolic and genetic characteristics of a child with carnitine palmitoyl transferase 1A (CPT1A) deficiency. METHODS: Clinical data and the level of acylcarnitine for a child who initially presented as epilepsy were analyzed. Genomic DNA was extracted from peripheral blood samples of the child and her parents and subjected to next-generation sequencing (NGS). RESULTS: Mass spectrometry of blood acylcarnitine indicated increased carnitine 0 (C0) and significantly increased C0/ (C16+C18). DNA sequencing revealed that the child has carried compound heterozygous variants of the CPT1A gene, namely c.1846G>A and c.2201T>C, which were respectively inherited from her mother and father. CONCLUSION CPT1A presenting initially as epilepsy was unreported previously. Analysis of blood acylcarnitine C0 and C0/ (C16 + C18) ratio and NGS are necessary for the identification and diagnosis of CPT1A deficiency. The c.1846G>A and c.2201T>C variants of the CPT1A gene probably underlay the disease in this child. Above finding has also enriched the spectrum of CPT1A gene variants.
Carnitine/blood* ; Carnitine O-Palmitoyltransferase/genetics* ; Child ; DNA Mutational Analysis ; Female ; Humans ; Hypoglycemia/genetics* ; Lipid Metabolism, Inborn Errors/genetics*

von Hippel-Lindau (VHL) disease is an inherited syndrome manifesting with benign and malignant tumors. Deficiency of carnitine palmitoyltransferase type II (CPT2) is a disorder of lipid metabolism that, in the muscle form, manifests with recurrent attacks of myalgias often associated with myoglobinuria. Rhabdomyolytic episodes may be complicated by life-threatening events, including acute renal failure (ARF). We report on a male patient who was tested, at 10 years of age, for VHL disease because of family history of VHL. He was diagnosed with VHL but without VHL-related manifestation at the time of diagnosis. During childhood, the patient was hospitalized several times for diffuse muscular pain, muscle weakness, and dark urine. These recurrent attacks of rhabdomyolysis were never accompanied by ARF. The patient was found to be homozygous for the mutation p.S113L of the CPT2 gene. To the best of our knowledge, this is the first report of the coexistence of VHL disease and CPT2 deficiency in the same individual. Based on findings from animal models, the case illustrates that mutations in the VHL gene might protect against renal damage caused by CPT2 gene mutations.
Acute Kidney Injury ; Carnitine O-Palmitoyltransferase ; Diagnosis ; Humans ; Lipid Metabolism ; Male ; Models, Animal ; Myalgia ; Myoglobinuria ; Rhabdomyolysis ; von Hippel-Lindau Disease

Lipids play many structural and metabolic roles, and dietary fat has great impact on metabolism and health. Fatty acid oxidation rate is dependent on tissue types. However there has been no report on the relationship between the rate of fatty acid oxidation and carnitine transport system in outer mitochondrial membrane of many tissues. In this study, the rate of fatty acid oxidation and carnitine palmitoyltransferase (CPT) I activity in the carnitine transport system were measured to understand the metabolic characteristics of fatty acid in various tissues. Palmitic acid oxidation rate and CPT I activity in various tissues were measured. Tissues were obtained from the white and red skeletal muscles, heart, liver, kidney and brain of rats. The highest lipid oxidation rate was demonstrated in the cardiac muscle, and the lowest oxidation rate was in brain. Red gastrocnemius muscle followed to the cardiac muscle. Lipid oxidation rates of kidney, white gastrocnemius muscle and liver were similar, ranging from 101 to 126 DPM/mg/hr. CPT I activity in the cardiac muscle was the highest, red gastrocnemius muscle followed by liver. Brain tissue showed the lowest CPT I activity as well as lipid oxidation rate, although the values were not significantly different from those of kidney and white gastrocnemius muscle. Therefore, lipid oxidation rate was highly (p< 0.001) related to CPT I activity. Lipid oxidation rate is variable, depending on tissue types, and is highly (p< 0.001) related to CPT I activity. CPT I activity may be a good marker to indicate lipid oxidation capacity in various tissues.
Animals ; Brain ; Carnitine O-Palmitoyltransferase ; Carnitine* ; Dietary Fats ; Heart ; Kidney ; Liver ; Metabolism ; Mitochondrial Membranes ; Muscle, Skeletal ; Myocardium ; Palmitic Acid ; Rats* ; Transferases*

Myostatin (Mstn) is known as growth/differentiation factor-8 (GDF-8). Knockout or knockdown of Mstn gene promotes muscle development and reduces fat content. Here we prepared Mstn knockdown mice by RNA interference, then the morphology of the skeletal muscle, the content of triglyceride (TG), the content and composition of fatty acids in the skeletal muscle were detected. The expression of Mstn reduced in muscle of Mstn knockdown mice compared to the controls. The cross sectional areas of the skeletal muscle myofibers were significantly larger while the content of TG was less than that of the controls, and the ratios of n-3/n-6 and unsat/sat in the knockdown mice increased significantly. Subsequently, we detected the expression of genes associated with fatty acid metabolism. The expression of the genes associated with lipolysis and fatty acid transportation were up-regulated, while the genes associated with fatty acid synthesis were down-regulated. Of these genes, the up-regulation of a gene associated with β oxidation, Cpt1b, was up-regulated remarkably. We further detected the enzyme activity of CPT1 in skeletal muscle and obtained the same results with gene expression. Moreover, chromatin immunoprecipitation assay was performed and we found that SMAD3, a transcription factor downstream of Mstn, directly binds to the promoter of Cpt1b gene. These results showed that knockdown of Mstn up-regulated the expression of Cpt1b through the binding of SMAD3 to the promoter of Cpt1b, then promoted the β oxidation metabolism of intramuscular fatty acids.
Animals ; Carnitine O-Palmitoyltransferase/metabolism* ; Fatty Acids ; Lipid Metabolism ; Mice ; Mice, Knockout ; Muscle, Skeletal/metabolism* ; Myostatin/metabolism* ; Oxidation-Reduction ; Up-Regulation

OBJECTIVETo analyze the clinical and molecular features of a child with carnitine palmitoyltransferase 1A (CPT1A) deficiency.

METHODSClinical data of the child was collected. Blood acylcarnitine was determined with tandem mass spectrometry. DNA was extracted from the child and his parents. All exons and flanking regions of the CPT1A gene were analyzed by PCR and Sanger sequencing.

RESULTSAnalysis showed that the patient carried compound heterozygous mutations c.1787T>C and c.2201T>C of the CPT1A gene, which derived his father and mother, respectively. Both mutations were verified as novel through the retrieval of dbSNP, HGMD and 1000 genome databases. Bioinformatic analysis suggested that the mutations can affect protein function.

CONCLUSIONAcyl carnitine analysis has been the main method for the diagnosis of CPT1A deficiency. The c.1787T>C and c.2201T>C mutations of the CPT1A gene probably underlie the disease in this patient. Gene testing can provide important clues for genetic counseling and prenatal diagnosis.

Base Sequence ; Carnitine O-Palmitoyltransferase ; deficiency ; genetics ; Exons ; Female ; Humans ; Hypoglycemia ; enzymology ; genetics ; Infant ; Lipid Metabolism, Inborn Errors ; enzymology ; genetics ; Male ; Molecular Sequence Data ; Point Mutation ; Pregnancy

BACKGROUND: Previous studies have shown that 17beta-estradiol activates AMP-activated protein kinase (AMPK) in rodent muscle and C2C12 myotubes and that acute 17beta-estradiol treatment rapidly increases AMPK phosphorylation possibly through non-genomic effects but does not stimulate glucose uptake. Here, we investigated whether 24-hour 17beta-estradiol treatment stimulated glucose uptake and regulated the expression of genes associated with glucose and energy metabolism through the genomic effects of estrogen receptor (ER) in C2C12 myotubes. METHODS: C2C12 myotubes were treated with 17beta-estradiol for 24 hours, and activation of AMPK, uptake of glucose, and expression of genes encoding peroxisome proliferator-activated receptor γ coactivator 1α, carnitine palmitoyltransferase 1β, uncoupling protein 2, and glucose transporter 4 were examined. Furthermore, we investigated whether AMPK inhibitor (compound C) or estrogen receptor antagonist (ICI182.780) treatment reversed 17beta-estradiol-induced changes. RESULTS: We found that 24-hour treatment of C2C12 myotubes with 17beta-estradiol stimulated AMPK activation and glucose uptake and regulated the expression of genes associated with glucose and energy metabolism. Treatment of C2C12 myotubes with the estrogen receptor antagonist (ICI182.780) reversed 17beta-estradiol-induced AMPK activation, glucose uptake, and changes in the expression of target genes. Furthermore, treatment with the AMPK inhibitor (compound C) reversed 17beta-estradiol-induced glucose uptake and changes in the expression of target genes. CONCLUSION: Our results suggest that 17beta-estradiol stimulates AMPK activation and glucose uptake and regulates the expression of genes associated with glucose and energy metabolism in C2C12 myotubes through the genomic effects of ER.
AMP-Activated Protein Kinases ; Carnitine O-Palmitoyltransferase ; Energy Metabolism ; Estrogens ; Glucose Transport Proteins, Facilitative ; Glucose ; Muscle Fibers, Skeletal ; Peroxisomes ; Phosphorylation ; Rodentia

OBJECTIVETo investigate the effects of maternal nutritional manipulation on fetal mRNA abundance of uncoupling protein UCP2, UCP3 and carnitine palmityl transferase 1 (CPT1), and find out an optimal maternal diet and targets for pharmacological prevention and treatment of obesity.

METHODSWistar pregnant rats were assigned to two groups which received a standard diet (SD) and a high protein diet (HPD) during pregnancy, respectively. After delivery, the male offspring were assigned to control group (CON) and high protein group (HP) according to their maternal diet, which were suckled by dams that received SD during pregnancy. Offspring were fed with SD from weaning (week 3) to week 8. Then CON were allocated to two groups: CON (SD during the whole experiment); HFCON (high fat control). HFCON and HP group rats were fed with high-fat diet (HFD) for 6 wk to induce obesity. At 0, 3, 8 and 14 wk of age, blood and tissue were collected for analyzing blood fat and abundance of UCP2, 3 and CPT1 mRNA.

RESULTSIn HP body weight and TG were decreased after weaning (F = 4.589, P = 0.039; F = 27.001, P = 0.000) and HFD (F = 16.076, P = 0.00; F = 71.518, P = 0.000). Obesity rates were significantly decreased in HP after HFD (chi2 = 8.076, P = 0.004). The abundance of UCP3 and CPT1 mRNA was persistently higher in HP than in CON or HFCON, and the abundance of UCP2 mRNA was also persistently higher than in CON or HFCON after weaning. Moreover the abundance of CPT1 mRNA was significantly increased after weaning and HFD compared with that after SD, the abundance of UCP2, UCP3 mRNA was also increased after HFD compared with that after SD.

CONCLUSIONSIncreasing protein intake during pregnancy might prevent offspring from HFD-induced obesity in adult, moreover might increase offspring the expression of UCP2, UCP3 and CPT1 mRNA. UCP2, UCP3 and CPT1 might participate in prevention and treatment of obesity by mediating fatty acid oxidation.

Animal Feed ; Animals ; Animals, Newborn ; Carnitine O-Palmitoyltransferase ; metabolism ; Dietary Proteins ; Female ; Fertile Period ; Ion Channels ; metabolism ; Male ; Mitochondrial Proteins ; metabolism ; Obesity ; metabolism ; Pregnancy ; RNA, Messenger ; genetics ; Rats ; Rats, Wistar ; Uncoupling Protein 2 ; Uncoupling Protein 3

OBJECTIVETo determine the roles of mitochondrial apoptosis and energy metabolism in hepatocytes during the pathogenic process of acute renal failure (ALF) by assessing disease-related differential activities of several key mitochondrial enzymes, including citrate synthase (CS), carnitine palmitoyltransferase-1 (CPT-1) and cytochrome c oxidase (COX).

METHODSThirty-two male Sprague Dawley rats were given D-galactosamine followed by and lipopolysaccharide (LPS) to induce acute liver failure and sacrificed after 4 (4 h group), 8 (8 h group) 12 (12 h group) and 24 hours (24 h group) of treatment. Eight unmodeled rats served as controls. Effects related to apoptosis were evaluated by pathological analysis of hepatic tissues and TUNEL staining. Ultrastructural changes in mitochondria were assessed by electron microscopy. The activity and expression of CS, CPT-1 and COX were measured.

RESULTSHepatocyte apoptosis was present in the 4 h treatment group and was increased obviously in the 8 h treatment group. Hepatocyte necrosis was first observed in the 12 h treatment group and was significantly higher in the 24 h treatment group, with inflammatory cell invasion. Ultrastructural changes in mitochondria were present in the 4 h treatment group, and the 24 h treatment group showed mitochondria with completely destroyed outer membranes, which resulted in mitochondrial collapse. Activity and protein expression of CS, CPT-1 and COX were increased in the 4 h group (vs. controls), were at their peak in the 8 h group (CS:t =1.481, P less than 0.01; CPT-1:t =2.619, P less than 0.05; COX:t =1.014, P less than 0.01) and showed a decreasing trend in the 12 h group. In addition, the activities of CS, CPT-1 and COX were enhanced at the stage of hepatocyte apoptosis, suggesting that these enzymes were involved in the initiation and development of ALF.

CONCLUSIONEnergy metabolism plays an important role in hepatocyte apoptosis during ALF.

Animals ; Apoptosis ; Carnitine O-Palmitoyltransferase ; metabolism ; Citrate (si)-Synthase ; metabolism ; Disease Models, Animal ; Electron Transport Complex IV ; metabolism ; Hepatocytes ; cytology ; enzymology ; Liver Failure, Acute ; metabolism ; pathology ; Male ; Mitochondria ; ultrastructure ; Rats ; Rats, Sprague-Dawley