RESUMEN
Children with long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency (LCHAD) have a defect in the degradation of long-chain fatty acids and are at risk of hypoketotic hypoglycemia and insufficient energy production as well as accumulation of toxic fatty acid intermediates. Knowledge on substrate metabolism in children with LCHAD deficiency during fasting is limited. Treatment guidelines differ between centers, both as far as length of fasting periods and need for night feeds are concerned. To increase the understanding of fasting intolerance and improve treatment recommendations, children with LCHAD deficiency were investigated with stable isotope technique, microdialysis, and indirect calometry, in order to assess lipolysis and glucose production during 6 h of fasting. We found an early and increased lipolysis and accumulation of long chain acylcarnitines after 4 h of fasting, albeit no patients developed hypoglycemia. The rate of glycerol production, reflecting lipolysis, averaged 7.7 ± 1.6 µmol/kg/min, which is higher compared to that of peers. The rate of glucose production was normal for age; 19.6 ± 3.4 µmol/kg/min (3.5 ± 0.6 mg/kg/min). Resting energy expenditure was also normal, even though the respiratory quotient was increased indicating mainly glucose oxidation. The results show that lipolysis and accumulation of long chain acylcarnitines occurs before hypoglycemia in fasting children with LCHAD, which may indicate more limited fasting tolerance than previously suggested.
Asunto(s)
3-Hidroxiacil-CoA Deshidrogenasas/deficiencia , Cardiomiopatías/enzimología , Metabolismo Energético , Ayuno/sangre , Errores Innatos del Metabolismo Lipídico/enzimología , Lipólisis , Miopatías Mitocondriales/enzimología , Enfermedades del Sistema Nervioso/enzimología , Rabdomiólisis/enzimología , 3-Hidroxiacil-CoA Deshidrogenasas/sangre , Factores de Edad , Biomarcadores/sangre , Glucemia/metabolismo , Calorimetría Indirecta , Cardiomiopatías/sangre , Cardiomiopatías/diagnóstico , Cardiomiopatías/dietoterapia , Carnitina/análogos & derivados , Carnitina/sangre , Niño , Preescolar , Femenino , Glicerol/sangre , Humanos , Hiperglucemia/sangre , Hiperglucemia/diagnóstico , Hiperglucemia/enzimología , Marcaje Isotópico , Errores Innatos del Metabolismo Lipídico/sangre , Errores Innatos del Metabolismo Lipídico/diagnóstico , Errores Innatos del Metabolismo Lipídico/dietoterapia , Masculino , Microdiálisis , Miopatías Mitocondriales/sangre , Miopatías Mitocondriales/diagnóstico , Miopatías Mitocondriales/dietoterapia , Proteína Trifuncional Mitocondrial/deficiencia , Enfermedades del Sistema Nervioso/sangre , Enfermedades del Sistema Nervioso/diagnóstico , Enfermedades del Sistema Nervioso/dietoterapia , Periodo Posprandial , Rabdomiólisis/sangre , Rabdomiólisis/diagnóstico , Rabdomiólisis/dietoterapia , Factores de TiempoRESUMEN
We examined the effect of exercise intensity and endurance training on plasma free fatty acid (FFA) kinetics and lipid metabolism in swimming muscles of reared sea trout. In both training groups [water current velocities 1 and 2 body lengths per second (bl s(-1))] the plasma level of FFAs decreased significantly (P < 0.001) compared to the control group. Similar significant (P < 0.01) post-exercise decrease was observed also in the lipase-esterase activity in the red muscle, but not in white. Moreover, in the group swimming with higher intensity a significantly higher (P < 0.05) lipase-esterase activity in the red muscle was found compared with the group on moderate exercise. As with cytochrome c oxidase activity, a significant elevation in the enzyme activity was also observed after training in the 1 bl s(-1) group in red and white muscle (P < 0.05 and P < 0.01, respectively). No changes were observed in beta hydroxyacyl CoA dehydrogenase activity. The lipid content was on average nine times higher in red compared to white muscle being 16.7, 21.1, and 24.9% in the red muscle of the control, 1 and 2 bl s(-1) groups, respectively, with a significant (P < 0.05) increase after training. We conclude that (1) unlike in mammals, plasma FFA kinetics and oxidation are not linearly related to exercise intensity in reared sea trout, (2) training enhances the capacity to uptake FFA from plasma, and (3) high intensity training shifts the proportion of energy derived from fat oxidation to carbohydrate-derived energy.
Asunto(s)
Metabolismo de los Lípidos/fisiología , Condicionamiento Físico Animal , Natación/fisiología , Trucha/fisiología , 3-Hidroxiacil-CoA Deshidrogenasas/sangre , Animales , Complejo IV de Transporte de Electrones/sangre , Ácidos Grasos no Esterificados/sangre , Femenino , Lipasa/metabolismo , Masculino , Músculo Esquelético/fisiología , Resistencia Física/fisiologíaRESUMEN
Peroxisome biogenesis disorders (PBDs) and D-bifunctional protein (D-BP) deficiency are two types of inherited peroxisomal disorders. Patients with a PBD lack functional peroxisomes and patients with D-BP deficiency lack the enzyme, which is responsible for the second and third step of the peroxisomal beta-oxidation. The clinical presentation of these peroxisomal disorders is severe and includes several neurological abnormalities. The pathological mechanisms underlying these disorders are not understood and no therapies are available. Because peroxisomes have been associated with oxidative stress, as oxygen radicals are both produced and scavenged in peroxisomes, we have investigated whether oxidative stress is involved in the pathogenesis of PBDs and D-BP deficiency. We found in D-BP-deficient patients increased levels of thiobarbituric acid-reactive substances (TBARS) and 8-hydroxydeoxyguanosine (8-OHdG), which are markers for lipid peroxidation and oxidative DNA damage, respectively, whereas the levels of the lipophilic antioxidants alpha-tocopherol and coenzyme Q(10) were decreased. In addition, we found in skin fibroblasts from D-BP-deficient patients an imbalance between the activities of the peroxisomal H(2)O(2)-generating straight-chain acyl-CoA oxidase (SCOX) and the peroxisomal H(2)O(2)-degrading enzyme catalase. In conclusion, we have found clear evidence for the presence of increased oxidative stress in patients with D-BP deficiency, but not in patients with a PBD.
Asunto(s)
17-Hidroxiesteroide Deshidrogenasas , 3-Hidroxiacil-CoA Deshidrogenasas/deficiencia , Desoxiguanosina/análogos & derivados , Enoil-CoA Hidratasa , Hidroliasas/deficiencia , Complejos Multienzimáticos/deficiencia , Estrés Oxidativo , Trastorno Peroxisomal/diagnóstico , Peroxisomas/enzimología , Ubiquinona/análogos & derivados , 3-Hidroxiacil-CoA Deshidrogenasas/sangre , 3-Hidroxiacil-CoA Deshidrogenasas/orina , 8-Hidroxi-2'-Desoxicoguanosina , Línea Celular , Coenzimas , Desoxiguanosina/análisis , Fibroblastos , Humanos , Hidroliasas/sangre , Hidroliasas/orina , Peroxidación de Lípido , Complejos Multienzimáticos/sangre , Complejos Multienzimáticos/orina , Trastorno Peroxisomal/sangre , Trastorno Peroxisomal/orina , Proteína-2 Multifuncional Peroxisomal , Sustancias Reactivas al Ácido Tiobarbitúrico/análisis , Ubiquinona/análisis , Ubiquinona/sangre , alfa-Tocoferol/análisis , alfa-Tocoferol/sangre , gamma-Tocoferol/análisis , gamma-Tocoferol/sangreRESUMEN
Diagnostic protocols for disorders of mitochondrial fatty acid oxidation (FAO) generally include the measurement of plasma acylcarnitines. Many biochemical intermediates of FAO resulting from a metabolic block require carnitine conjugation for transport out of the mitochondria, and so occur as fatty acid carnitine conjugates in the blood. Both short- and long-chain acylcarnitines are generally determined, and this procedure has a critical role to play in the diagnosis of disorders of the very long-chain, medium-chain and short-chain acyl-CoA dehydrogenase defects. Less is known about the utility of acylcarnitines for the measurement of the various chain length intermediates of the 3-hydroxyacyl-CoA dehydrogenase steps of beta-oxidation. This study utilizes stable-isotope dilution gas chromatography-mass spectrometry to determine the serum or plasma concentrations of free 3-hydroxy fatty acids (3-OHFAs) of chain lengths C6 to C16. The 3-OHFA concentrations are determined in samples from normal individuals, hyperketotic individuals and patients with long-chain L-3-hydroxyacyl-CoA dehydrogenase and short-chain L-3-hydroxyacyl-CoA dehydrogenase deficiencies, both before and after hydrolysis. The results of the study indicate the relative amounts of conjugated intermediates of all chain lengths. Long-chain 3-OHFAs (C14 and C16) are found in elevated concentrations after hydrolysis, whereas short-chain and medium-chain 3-OHFAs (C6 to C12) show no difference in concentrations between the two samples in all subjects tested, suggesting that only long-chain 3-hydroxy species form conjugates. This finding has important implications for the use of the acylcarnitine assay for the diagnosis of defects involving short-chain and medium-chain 3-hydroxy fatty acids.
Asunto(s)
3-Hidroxiacil-CoA Deshidrogenasas/deficiencia , Acil-CoA Deshidrogenasa de Cadena Larga/deficiencia , Ácidos Grasos no Esterificados/sangre , 3-Hidroxiacil-CoA Deshidrogenasas/sangre , Acil-CoA Deshidrogenasa , Acil-CoA Deshidrogenasa de Cadena Larga/sangre , Esterificación , Humanos , 3-Hidroxiacil-CoA Deshidrogenasa de Cadena LargaRESUMEN
This experiment was undertaken to determine whether there were differences in cardiorespiratory, haematological and muscular responses in horses trained at either low or moderate intensities. Ten Thoroughbred horses previously rested in paddocks for 4 months were trained 5 days/week for 9 weeks. Horses were allocated randomly into fast or slow groups and exercised the same distance each day. Training distances were 1600 m in Weeks 0 and 1 up to 4000 m in Week 9. The fast group were trained at an intensity inducing a post training blood lactate of 4-8 mmol/l. This intensity was determined for each horse each week. The slow group trained at half the speed of the fast group (blood lactate < 2 mmol/l). Horses performed a standardised exercise test prior to (Week 0) and on Weeks 1, 2, 3, 4, 7 and 9 of training. HR, VO2, VCO2 and blood lactate concentration were recorded during the last 15 s of each step. Blood samples were collected at the end of each test for determination of red cell and plasma volume. Muscle biopsies were collected from the middle gluteal muscle before training and after 4 and 9 weeks training. Training intensity had few effects on the majority of variables measured and results for both groups are combined unless otherwise stated. Bodyweight was unaffected by training. Economy of locomotion decreased from 12.0 +/- 0.4 ml/kg bwt/m prior to training to 13.8 +/- 0.6 ml/kg bwt/m at the end of training in the fast group. Run time to fatigue was not affected by training intensity. VO2max increased from 120.3 +/- 4.8 to 144.7 +/- 3.5 ml/kg bwt/min with a significant correlation between run time and VO2max. Peak HR was 221.4 +/- 2.5 beats/min prior to training and 226.5 +/- 1.7 beats/min after the first 4 weeks of training. V200 and VLa4 increased in response to training. Similarly, VLa4 increased from 7.0 +/- 0.5 to 9.2 +/- 0.2 m/s with VLa4 correlated to VO2max. Plasma volume decreased from 29.1 +/- 1.7 to 25.8 +/- 0.9 l during the last 3 weeks of training. Blood volume, red cell volume and/or red cell volume/kg were unaffected by intensity or duration of training. The activity of CS in muscle increased in the first 5 weeks of training whereas HAD activity was not affected by intensity or duration of training.
Asunto(s)
Metabolismo Energético , Caballos/fisiología , Condicionamiento Físico Animal , 3-Hidroxiacil-CoA Deshidrogenasas/sangre , Animales , Volumen Sanguíneo , Peso Corporal , Citrato (si)-Sintasa/sangre , Frecuencia Cardíaca , Ácido Láctico/sangre , Consumo de OxígenoRESUMEN
The final steps in bile acid biosynthesis take place in peroxisomes and involve oxidative cleavage of the side chain of C27-5beta-cholestanoic acids leading to the formation of the primary bile acids cholic acid and chenodeoxycholic acid. The enoyl-CoA hydratase and beta-hydroxy acyl-CoA dehydrogenase reactions involved in the chain shortening of C27-5beta-cholestanoic acids are catalyzed by the recently identified peroxisomal d-bifunctional protein. Deficiencies of d-bifunctional protein lead, among others, to an accumulation of 3alpha,7alpha,12alpha, 24-tetrahydroxy-5beta-cholest-26-oic acid (varanic acid). The ability to resolve the four C24, C25 diastereomers of varanic acid has, so far, only been carried out on biliary bile acids using p -bromophenacyl derivatives. Here, we describe a sensitive gas chromatography-mass spectrometry (GC/MS) method that enables good separation of the four varanic acid diastereomers by use of 2R-butylester-trimethylsilylether derivatives. This method showed the specific accumulation of (24R,25R)-varanic acid in the serum of a patient with isolated deficiency of the d-3-hydroxy acyl-CoA dehydrogenase part of peroxisomal d-bifunctional protein, whereas this diastereomer was absent in a serum sample from a patient suffering from complete d-bifunctional protein deficiency. In samples from both patients an accumulation of (24S,25S)-varanic acid was observed, most likely due to the action of l-bifunctional protein on Delta24E-THCA-CoA. This GC/MS method is applicable to serum samples, obviating the use of bile fluid, and is a helpful tool in the subclassification of patients with peroxisomal d-bifunctional protein deficiency.
Asunto(s)
17-Hidroxiesteroide Deshidrogenasas , 3-Hidroxiacil-CoA Deshidrogenasas/sangre , Colestanoles/sangre , Hidroliasas/sangre , Microcuerpos/metabolismo , Complejos Multienzimáticos/sangre , Complejos Multienzimáticos/deficiencia , Trastorno Peroxisomal/sangre , Enoil-CoA Hidratasa/sangre , Cromatografía de Gases y Espectrometría de Masas , Humanos , Proteína-2 Multifuncional Peroxisomal , Valor Predictivo de las Pruebas , Sensibilidad y Especificidad , EstereoisomerismoRESUMEN
Relationships between functional anaerobic indicators and the character of cellular muscle energy metabolism were studied. Twelve untrained male students were tested by a specific anaerobic test on the treadmill. The mean values of the anaerobic test were as follows: blood lactate 10.69 mmol . 1(-1), running speed 16.08 km . h-1 and duration 92.67 s. The average distribution of muscle fibres (m. vastus lateralis) was: type I 52.2%, type II A 29.0% and type II B 18.8%. The mean enzyme activity values were: triosephosphate dehydrogenase (TPDH) 4.67 mu kat . g-1 w.w., lactate dehydrogenase (LDH) 5.76 mu kat . g-1 w.w, citrate synthase (CS) 0.21 mu kat . g-1 w.w. and hydroxyacyl-CoA dehydrogenase (HAD) 0.12 mu kat . g-1 w.w. Significant negative correlations were found between delta LA and CS (r = 0.64) and % of fibre type II B and CS (r = 0.78) and positive correlations between % of fibre type I and CS and/or HAD (r = 0.60 and r = 0.62, respectively).