Efeitos do D-limoneno no metabolismo energético de camundongos C57/Bl6 com obesidade induzida pela dieta / Effects of D-limonene on the energy metabolism of C57/Bl6 mice with diet-induced obesity

A obesidade está associada ao desenvolvimento de doenças crônicas não transmissíveis como hipertensão, resistência insulínica, dislipidemia e esteatose hepática. O consumo de compostos bioativos impacta na manutenção da saúde e na prevenção de risco de desenvolvimento dessas doenças. Entre os compostos bioativos, os monoterpenos são pouco investigados, apesar da literatura demonstrar efeitos promissores desses compostos sobre o metabolismo. O D-limoneno, o principal monoterpeno encontrado na laranja, é caracterizado por possuir efeitos hipolipemiantes, anti-inflamatórios e anti-obesogênicos. Estudos in vitro e in vivo descrevem sua capacidade de promover a ß-oxidação de ácidos graxos em adipócitos e redução da inflamação. Este estudo teve como objetivo investigar o efeito do D-limoneno no metabolismo e inflamação em um modelo de obesidade induzida por dieta. Para isso, quarenta camundongos machos (C57/Bl6) de 11 semanas de idade, foram distribuídos em 4 grupos, sendo que um dos grupos recebeu ração normolipídica e os demais, ração hiperlipídica. O D-limoneno foi suplementado na ração de dois grupos que receberam dieta hiperlipídica nas concentrações de 0,1%, e 0,8%. Considerando-se a ingestão alimentar dos animais, a ração suplementada com 0,1% D-limoneno correspondeu à ingestão de 0,15 g/kg/dia e ração com 0,8% de D-limoneno correspondeu a 1,3 g/kg/dia. Os animais tiveram o peso e a ingestão alimentar monitorados ao longo da intervenção com duração de 7 semanas. Os camundongos que receberam D-limoneno a 0,1% apresentaram menor ganho de peso e de acúmulo de tecido adiposo, comparado com os animais sem suplementação alimentados com a dieta hiperlipídica. Além disso, o D-limoneno promoveu a diminuição da concentração plasmática de marcadores inflamatórios incluindo TNF-α, INF-γ e IL-6 nos animais dos grupos que foram suplementados com D-limoneno. Entretanto, não houve diferença nos marcadores bioquímicos e metabólicos. Uma limitação do estudo foi o fato das complicações metabólicas associadas ao modelo de obesidade não terem sido plenamente estabelecidas, dados o alojamento individual, à curta duração da exposição à ração hiperlipídica e idade dos animais no início da suplementação. Esse fato pode ter dificultado a observação dos efeitos do D-limoneno na reversão dos parâmetros que seriam normalmente deteriorados pelo desenvolvimento da obesidade. Concluímos que o D-limoneno pode interferir no metabolismo energético, com possível efeito anti-obesogênico e anti-inflamatório. Devido às limitações do modelo, são necessários mais estudos para confirmar esses resultados

Obesity is associated with the development of chronic non-communicable diseases such as hypertension, insulin resistance, dyslipidemia, and hepatic steatosis. The intake of dietary bioactive compounds is associated with the maintenance of health and the prevention of chronic diseases. Among the group of bioactive compounds, monoterpenes are poorly investigated, in spite of several reports of their promising effects on metabolism. D-limonene is the main monoterpene found in oranges, known for its hypolipemic, anti-inflammatory, and anti-obesogenic effects. in vitro and in vivo studies associate D-limonene to increased ß-oxidation of fatty acids in adipocytes and reduced inflammation. This study aimed at investigating the effects of D-limonene on metabolism and inflammation in a diet-induced obesity model. For this purpose, forty male mice (C57/Bl6) were distributed in 4 groups, with one group receiving a normolipidic diet and the others, a high-fat diet. D-limonene was supplemented in the diets of two groups that received high-fat diet at the concentrations of 0.1% and 0.8%. Considering the feed intake, mice receiving D-limonene supplementation at 0.1% ingested in average 0.15 g/kg/day, while the mice receiving the supplemmentation at 0.8%, ingested approximately 1.3 g of D-limonene /kg/day. The animals had their weight and food intake monitored throughout the intervention. Mice that received Dlimonene supplementation at 0.1% showed reduced weight gain and accumulation of adipose tissue compared to the non-supplemented mice fed the high-fat diet. In addition, D-limonene promoted a decrease in hepatic inflammatory markers including TNF-α, INF-γ, and IL-6. However, there was no difference in biochemical and metabolic markers. A limitation of the study was that the metabolic complications associated with the obesity model were not fully established, probably due to the age at the start of the protocol (11 weeks), individual housing and short duration of the exposure to the high-fat feed. This fact may have prevented the observation of the positive effects of D-limonene in reversing parameters that would normally be impaired by the development of obesity. We conclude that D-limonene may interfere in energy metabolism, with a possible anti-obesogenic and anti-inflammatory effect. Due to the limitations of the model, further studies are needed to confirm these findings

Riboflavin inhibits heart failure in mice by activating SCAD / 中国药理学通报

Aim To explore the effeet of riboflavin on the establishment of pressure overload-induced heart failure model in mice by thoracic aortie constrietion (TAC ) and its preventive mechanism.Methods Eight-week-old SPF C57BL/6J mice were seleeted and divided into four groups; Sham group.Sham + ribofla¬vin group, TAC group and TAC + riboflavin group.A mouse heart failure model was constructed in the TAC group.The miee in the TAC + riboflavin group were given riboflavin by gavage one week before and eight weeks after the operation.The cardiac ultrasound inde¬xes, the changes of cardiac morphology and mitochon¬drial function indexes, the expression of apoptosis pro¬teins, ATP content, SCAD mRNA and protein expres¬sion, enzyme activity and flavin adenine dinucleotide (FAD) content in myocardial tissues were detected.Hie free fatty acid content in serum and myocardial tis¬sues were also detected.Results Compared with the sham group, the cardiac function indexes of the mice in the TAC group decreased, anrl typical heart failure occurred.Moreover, the expression of SCAD, enzyme activity, ATP and FAD content in the myocardium sig-nificantly decreased, and the free fatty acid content in myocardium and serum significantly increased.Com¬pared with the TAC group, after riboflavin treatment, the cardiac function of mice in TAC + Riboflavin group was significantly improved.In addition, ATP content, SCAD expression, enzyme activity and FAD content in myocardium all significantly increased, and free fatty acid content in myocardium and serum markedly de¬creased.Conclusions Riboflavin may improve myo-cardial energy metabolism by increasing FAD content and activating SCAD, thereby inhibiting pressure over¬load-induced heart failure in mice.

An experimental study of SCAD recombinant adenovirus treating heart failure following myocardial infarction in rats / 中国药理学通报

Aim To investigate the effects of overexpression of short-chain acyl-CoA dehydrogenase (SCAD) recombinant adenovirus on heart failure following myocardial infarction in rats, and to explore the relationship between SCAD and heart failure. Methods The rat model of heart failure following myocardial infarction was established by ligation of left anterior descending coronary artery (LAD). The SCAD recombinant adenovirus was injected into the apical wall. The experimental groups were divided into 6 groups; Sham + NS group, LAD + NS group, Sham + Ad-GFP group, Sham + Ad-SCAD group, LAD + Ad-GFP group and LAD + Ad-SCAD group. Systolic blood pressure (SBP) of tail artery was measured after surgery and the cardiac morphological changes were detected. The changes of SCAD mRNA expression, protein expression, enzyme activity, ATP content and free fatty acid content were examined. Results Compared with sham group, LAD + NS group showed heart failure significantly. Compared with LAD + NS group, SBP from LAD + Ad-SCAD group increased obviously after surgery, collagen deposition was apparently reduced and myocardial fibrosis was markedly improved. Compared with Sham + NS group, the SCAD mRNA, protein expression, enzyme activity and ATP content in LAD + NS group obviously decreased, and the contents of free fatty acids markedly increased. Compared with LAD + NS group, the above indicators of LAD + Ad-SCAD group were evidently reversed after treated with SCAD recombinant adenovirus. Conclusion Overexpression of SCAD recombinant adenovirus in heart can significantly improve heart failure caused by LAD.

Newborn screening for fatty acid oxidation disorders / 中国实用儿科杂志

()of recessive hereditary diseases caused by the dysfunction of enzymes required for fatty acids to enter mitochondria or fatty acid beta-oxidation,including carnitine transport disorders and fatty acid beta-oxidation disorders. Clinical symptoms are non-specific,involving multiple organs,such as liver,myocardium,skeletal muscle,brain and kidney. Most FAOD patients diagnosed by newborn screening have no clinical symptoms or mild symptoms through early intervention management,but they are prone to acute onset or even sudden death under stress conditions such as hunger and exercise. Long-term follow-up and management can effectively reduce the mortality and morbidity rate of FAOD.

Both hepatic lipogenesis and beta-oxidation are altered in offspring of mothers fed a high-fat diet in the first two generations (F1 and F2) / La lipogénesis hepática y la beta-oxidación están alteradas en las crías de madres alimentadas con una dieta alta en grasas en las dos primeras generaciones (F1 y F2)

The high fat (HF) fed mothers may program susceptibility in offspring to chronic diseases and affect subsequent generations. The present study evaluated the liver structure in adulthood, focusing on the F1 and F2 generations. Females C57BL/6 (F0) were fed standard chow (SC) or HF diet (8 weeks) prior to mating and during the gestation and lactation to provide the F1 generation (SC-F1 and HF-F1). All other mothers and offspring fed SC. At 3 months old, F1 females were mated to produce the F2 generation (SC-F2 and HF-F2). The liver was kept in several fragments and prepared for histological analysis or frozen for biochemical and molecular analyzes. The F1 and F2 offspring were studied at 3 months old. HF-F1 had higher body mass (BM) compared to SC-F1 (P= 0.001), but not HF-F2 compared to SC-F2. HF-F1 had glucose intolerance when compared to SC-F1, but not HF-F2 compared to SC-F2. HF-F1 (P= 0.009) and HF-F2 (P= 0.03) showed hyperinsulinemia compared to their counterparts. Both groups HF-F1 and HF-F2 showed more steatosis than the SC counterparts (F1 and F2, P<0.0001). HF-F1 showed increased expression of PPAR-gamma and SREBP1-c compared to SC-F1 (P= 0.01). HF-F2 showed increased PPAR-gamma expression compared to SC-F2 (P= 0.04). In conclusion, HF-fed mother impairs both lipogenesis and beta-oxidation pathways in F1 through upregulation of PPAR-gamma and downregulation of PPAR-alpha. In F2, the only lipogenesis is enhanced, but it causes a disrupted PPAR balance, favoring the hepatic lipid accumulation and impaired metabolism in these animals that were not directly exposed to the maternal HF intake.

Los madres alimentadas con dieta rica en grasas (HF) pueden programar una susceptibilidad al desarrollo de enfermedades crónicas en su descendencia y de este modo afectar a las generaciones posteriores. El presente estudio evaluó la estructura del hígado en la edad adulta, centrándose en las generaciones F1 y F2. Las hembras C57BL/6 (F0) fueron alimentadas con dieta estándar (CS) o dieta HF (8 semanas) antes del apareamiento y durante la gestación y lactancia para producir la generación F1 (CS-F1 y HF-F1). Todas las demás madres y crías fueron alimentadas con CS. A los 3 meses de edad, las hembras F1 fueron apareadas para producir la generación F2 (CS-F2 y HF-F2). El hígado se conservó en varios fragmentos y se preparó, por un lado, para el análisis histológico, y por otro, se lo congeló para realizar análisis bioquímicos y moleculares. La descendencia F1 y F2 se estudió a los 3 meses de edad. HF-F1 tuvo una mayor masa corporal (BM) en comparación con CS-F1 (P= 0,001), pero no el grupo HF-F2 en comparación con CS-F2. HF-F1 tenía intolerancia a la glucosa en comparación con CS-F1, pero no el grupo HF-F2 en comparación con CS-F2. HF-F1 (P= 0,009) y HF-F2 (P= 0,03) mostraron hiperinsulinemia en comparación con sus homólogos. Ambos grupos HF-F1 y HF-F2 mostraron más esteatosis que las contrapartes CS (F1 y F2, P <0,0001). HF-F1 mostró una mayor expresión de PPAR-gamma y SREBP1-c en comparación con el grupo CS-F1 (P= 0,01). HF-F2 mostró aumento de la expresión de PPAR-gamma en comparación con CS-F2 (P= 0,04). En conclusión, la madre alimentada con HF presenta ambas vías afectadas, de lipogénesis y de la beta-oxidación, en la F1 a través de la regulación positiva de PPAR-gamma y con regulación a la baja de los PPAR-alfa. En F2, solo ha mejorado la vía de lipogénesis, pero causa un desbalance de PPAR, lo que favorece la acumulación de lípidos hepáticos y la alteración del metabolismo en estos animales que no estaban directamente expuestos a la ingesta materna de HF.

Effects of quercetin derivatives from mulberry leaves: Improved gene expression related hepatic lipid and glucose metabolism in short-term high-fat fed mice

BACKGROUND/OBJECTIVES: Mulberry leaves contain quercetin derivatives, which have the effects of reducing obesity and improving lipid and glucose metabolism in mice with obesity. It is not clear whether or not mulberry leaves can directly affect metabolic disorders, in the presence of obesity, because of the interaction between obesity and metabolic disorders. The aim of the current study was to assess the direct action of quercetin derivatives on metabolic disorders in non-obese conditions in short-term high-fat diet fed mice. MATERIALS/METHODS: C57BL/6N mice were fed a high-fat diet, supplemented with either 0% (control), 1%, or 3% mulberry leaf powder (Mul) or 1% catechin powder for five days. Anthropometric parameters and blood biochemistry were determined, and hepatic gene expression associated with lipid and glucose metabolism was analyzed. RESULTS: Body and white fat weights did not differ among the four groups. Plasma triglycerides, total cholesterol, and free fatty acids in the 1%, 3% Mul and catechin groups did not differ significantly from those of the controls, however, plasma glucose and 8-isoprostane levels were significantly reduced. Liver gene expression of gp91phox, a main component of NADPH oxidase, was significantly down-regulated, and PPAR-alpha, related to beta-oxidation, was significantly up-regulated. FAS and GPAT, involved in lipid metabolism, were significantly down-regulated, and Ehhadh was significantly up-regulated. Glucose-metabolism related genes, L-PK and G6Pase, were significantly down-regulated, while GK was significantly up-regulated in the two Mul groups compared to the control group. CONCLUSIONS: Our results suggest that the Mul quercetin derivatives can directly improve lipid and glucose metabolism by reducing oxidative stress and enhancing beta-oxidation. The 1% Mul and 1% catechin groups had similar levels of polyphenol compound intake (0.4 x 10(-5) vs 0.4 x 10(-5) mole/5 days) and exhibited similar effects, but neither showed dose-dependent effects on lipid and glucose metabolism or oxidative stress.

Effects of quercetin derivatives from mulberry leaves: Improved gene expression related hepatic lipid and glucose metabolism in short-term high-fat fed mice

BACKGROUND/OBJECTIVES: Mulberry leaves contain quercetin derivatives, which have the effects of reducing obesity and improving lipid and glucose metabolism in mice with obesity. It is not clear whether or not mulberry leaves can directly affect metabolic disorders, in the presence of obesity, because of the interaction between obesity and metabolic disorders. The aim of the current study was to assess the direct action of quercetin derivatives on metabolic disorders in non-obese conditions in short-term high-fat diet fed mice. MATERIALS/METHODS: C57BL/6N mice were fed a high-fat diet, supplemented with either 0% (control), 1%, or 3% mulberry leaf powder (Mul) or 1% catechin powder for five days. Anthropometric parameters and blood biochemistry were determined, and hepatic gene expression associated with lipid and glucose metabolism was analyzed. RESULTS: Body and white fat weights did not differ among the four groups. Plasma triglycerides, total cholesterol, and free fatty acids in the 1%, 3% Mul and catechin groups did not differ significantly from those of the controls, however, plasma glucose and 8-isoprostane levels were significantly reduced. Liver gene expression of gp91phox, a main component of NADPH oxidase, was significantly down-regulated, and PPAR-alpha, related to beta-oxidation, was significantly up-regulated. FAS and GPAT, involved in lipid metabolism, were significantly down-regulated, and Ehhadh was significantly up-regulated. Glucose-metabolism related genes, L-PK and G6Pase, were significantly down-regulated, while GK was significantly up-regulated in the two Mul groups compared to the control group. CONCLUSIONS: Our results suggest that the Mul quercetin derivatives can directly improve lipid and glucose metabolism by reducing oxidative stress and enhancing beta-oxidation. The 1% Mul and 1% catechin groups had similar levels of polyphenol compound intake (0.4 x 10(-5) vs 0.4 x 10(-5) mole/5 days) and exhibited similar effects, but neither showed dose-dependent effects on lipid and glucose metabolism or oxidative stress.

Estudio de la deficiencia de acil-CoA deshidrogenasa de cadena muy larga con cardiomiopatía mediante el uso de un sustrato deuterado / Study of very long chain acyl-CoA dehydrogenase (VLCAD) deficiency with cardiomyopathy using a deuterated substrate / Estudo da deficiência de acil-CoA desidrogenase de corrente muito longa com cardiomiopatia mediante o uso de um substrato deuterado Estudo da deficiência de acil-CoA desidrogenase de corrente muito longa com cardiomiopatia mediante o uso de um substrato deuterado

Introducción: la deficiencia de acil-CoA deshidrogenasa de cadena muy larga (VLCAD) se manifiesta en los primeros meses de vida con cardiomiopatía hipertrófica o dilatada y arritmias, que pueden llegar a ser letales. Objetivo: analizar la producción de metabolitos en fibroblastos de pacientes con deficiencia de VLCAD y cardiomiopatía, incubados con ácido oleico deuterado. Materiales y métodos: se incubaron fibroblastos de cuatro pacientes con deficiencia de VLCAD y cardiomiopatía y 10 de controles en presencia de ácido oleico deuterado. Resultados y conclusión: en pacientes con esta deficiencia se encontró un perfil característico luego de la incubación de los fibroblastos. Esta prueba se podría usar para confirmar in vitro la deficiencia de VLCAD con cardiomiopatía.

Introduction: Deficiency of VLCAD is present in the early months of life, with hypertrophic or dilated cardiomyopathy and arrhythmias which may be lethal. Objective: To analize the production of metabolites in fibroblasts from patientes with VLCAD deficiency and cardiomyopathy incubated with deuterated oleic acid. Materials and methods: Fibroblasts from four patients with VLCAD deficiency and cardiomyopathy and from ten controls were incubated in the presence of deuterated oleic acid. Results and conclusison: A characteristic profile was found in the fibroblastos of patients with VLCAD after the described incubation. This test could be used to confirm VLCAD deficiency with cardiomyopathy.

Introdução: a deficiência de acil-CoA desidrogenase de corrente muito longa (VLCAD) manifesta-se nos primeiros meses de vida com cardiomiopatia hipertrófica ou dilatada e arritmias, que podem chegar a ser letais. Objetivo: analisar a produção de metabólitos em fibroblastos de pacientes com deficiência de VLCAD e cardiomiopatia, incubados com ácido oleico deuterado. Materiais e métodos: incubaram-se fibroblastos de quatro pacientes com deficiência de VLCAD e cardiomiopatia e 10 de controles em presença de acido oleico deuterado. Resultados e conclusão: em pacientes com esta deficiência se encontrou um perfil característico depois da encubação dos fibroblastos. Esta prova se poderia usar para confirmar in vitro a deficiência de VLCAD com cardiomiopatia.

Distrofia muscular Duchenne y defecto de oxidación de ácidos graso en un paciente pediátrico / Duchenne muscular dystrophy and fatty acid oxidation defect in pediatric patient

Paciente pediátrico, con el diagnóstico de distrofia muscular de Duchenne y deficiencia de acil-CoA deshidrogenasa de cadenas medias, ambas patologías confirmadas por medio de análisis molecular, al detectarse la deleción de los exones 45 al 50 en el gen DMD, y la mutación A985G en estado homocigoto del gen ACADM...

Nonalcoholic fatty liver disease: molecular mechanisms for the hepatic steatosis

Liver plays a central role in the biogenesis of major metabolites including glucose, fatty acids, and cholesterol. Increased incidence of obesity in the modern society promotes insulin resistance in the peripheral tissues in humans, and could cause severe metabolic disorders by inducing accumulation of lipid in the liver, resulting in the progression of non-alcoholic fatty liver disease (NAFLD). NAFLD, which is characterized by increased fat depots in the liver, could precede more severe diseases such as non-alcoholic steatohepatitis (NASH), cirrhosis, and in some cases hepatocellular carcinoma. Accumulation of lipid in the liver can be traced by increased uptake of free fatty acids into the liver, impaired fatty acid beta oxidation, or the increased incidence of de novo lipogenesis. In this review, I would like to focus on the roles of individual pathways that contribute to the hepatic steatosis as a precursor for the NAFLD.

Estudio de pacientes con aciduria glutarica tipo II, mediante la incubacion de fibroblastos con acidos palmitico y miristico tritiados / Study of patients with type II glutaric aciduria by incubation of fibroblasts with tritiated palmitic and myristic acids

Introduccion: la aciduria glutarica tipo II, o deficiencia multiple de acil-CoA deshidrogenasas,es un trastorno causado por deficiencia de la flavoproteina de transferencia de electrones,de su oxidorreductasa o de ambas; se trata de una enfermedad metabolica autosomica recesiva, caracterizada por acidosis, hipoglicemia, aciduria organica, olor a pies sudados y malformaciones en cerebro y riñones. Objetivo: analizar las tasas de oxidacion de sustratos tritiados por fibroblastos de pacientescon aciduria glutarica tipo II. Materiales y metodos: se incubaron fibroblastos de dos pacientes con aciduria glutarica tipoII y de 20 controles en presencia de acidos palmitico y miristico tritiados. Resultados: se encontro muy deprimida (16%-18%) la oxidacion de los sustratos tritiados porlos fibroblastos procedentes de pacientes con aciduria glutarica tipo II en comparacion con los controles. Conclusion: la prueba estudiada permite la confirmacion in vitro del diagnostico de aciduriaglutarica tipo II.

Introduction: Glutaric aciduria type II (GA II), or multiple acyl-CoA dehydrogenase deficiency, is a disorder caused by deficiency of either electron transport flavoprotein or electron transport flavoprotein oxyreductase. It is an autsomal recessive metabolic disease, characterized by acidosis, hypoglycemia, organic aciduria, sweat-sock odour, and malformations in brain and kidneys. Objective: To analyse the oxidation rate of tritiated substrates by fibroblasts of patients with GA II. Materials and methods: Fibroblasts of two patients with GA II were incubated with tritiated palmitic and myristic acids. Results: Oxidation of tritiated substrates by fibroblasts of patients with GA II was very depressed (16%-18%) in comparison with controls. Conclusion: Diagnosis of GA II may be confirmed in vitro by the studied test.

Effect of dietary protamine on lipid metabolism in rats

Protamine has been widely used as a pharmaceutical product and natural food preservative. However, few studies have been conducted to assess the beneficial function of dietary protamine. This study examined the effects of dietary salmon protamine on serum and liver lipid levels and the expression levels of genes encoding proteins involved in lipid homeostasis in the liver of rats. Groups of male Wistar rats were fed AIN93G diet containing 2% or 5% protamine. After 4 weeks of feeding these diets, markedly decreased serum and liver cholesterol (CHOL) and triacylglycerol levels were noted. Increased activity of liver carnitine palmitoyltransferase-2 and acyl-CoA oxidase, which are key enzymes of fatty acid beta-oxidation in the mitochondria and peroxisomes, was found in rats fed on protamine. Furthermore, rats fed protamine showed enhanced fecal excretion of CHOL and bile acid and increased liver mRNA expression levels of ATP-binding cassette (ABC) G5 and ABCG8, which form heterodimers and play a major role in the secretion of CHOL into bile. The decrease in triacylglycerol levels in protamine-fed rats was due to the enhancement of liver beta-oxidation. Furthermore, rats fed protamine exhibited decreased CHOL levels through the suppression of CHOL and bile acid absorption and the enhancement of CHOL secretion into bile. These results suggest that dietary protamine has beneficial effects that may aid in the prevention of lifestyle-related diseases such as hyperlipidemia and atherosclerosis.

Fatty acid oxidation disorders / 한양의대학술지

Inborn errors of fatty acid mitochondrial oxidation (FAOD) have drawn considerable attention in recent years because of rapid pace of discovery of new defects and an ever-increasing spectrum of clinical phenotypes. This review describes a clinical and biochemical phenotypes, diagnosis and treatment of FAOD. Some of FAOD can not be detected by conventional biochemical investigations, even when a patient is symptomatic with fasting intolerance or functional failure of fatty acid dependent tissue (s). Diagnosis must ultimately be based on direct assay of the involved enzyme, however, preliminary indicators may come from determination of carnitine and intermediate metabolites in plasma, profiling of urine organic acid, and radioisotopic screening assays with lymphocytes or cultured fibroblasts. We are faced with the following major challenges: whether to include FAOD in newborn screening programs, the investigation of the rules played by individual disorders in maternal complication during pregnancy, sudden and unexpected death in early life, and pediatric acute/fulminant liver failure.

What is the Key Step in Muscle Fatty Acid Oxidation after Change of Plasma Free Fatty Acids Level in Rats?

The purpose of this study was to discern the critical point in skeletal muscle fatty acid oxidation by changing plasma free fatty acids (FFA) level in rat. In the study, 3 key steps in lipid oxidation were examined after changing plasma FFA level by acipimox. The rates of both palmitate and palmitoyl- carnitine oxidation were decreased by decrease of plasma FFA level, however, carnitine palmitoyl transferase (CPT) 1 activity was not changed, suggesting CPT1 activity may not be involved in the fatty acid oxidation at the early phase of plasma FFA change. In the fasted rats, beta-hydroxy acyl-CoA dehydrogenase (beta-HAD) activity was depressed to a similar extent as palmitate oxidation by a decrease of plasma FFA level. This suggested that beta-oxidation might be an important process to regulate fatty acid oxidation at the early period of plasma FFA change. Citrate synthase activity was not altered by the change of plasma FFA level. In conclusion, the critical step in fatty acids oxidation of skeletal muscles by the change of plasma FFA level by acipimox in fasting rats might be the beta-oxidation step rather than CPT1 and TCA cycle pathways.