The association of acylcarnitines and amino acids with age in Dutch and South-Asian Surinamese living in Amsterdam.

Type 2 diabetes and cardiovascular disease occur more frequently, and at a younger age in South-Asians than Europeans. This may be related to differences in regulation of the fatty acid metabolism during aging. We compared age-related acylcarnitine and amino acid concentrations. We measured types of acylcarnitine and amino acid concentrations in plasma (by tandem-MS) in a random subsample of 350 Dutch and 350 South-Asian Surinamese origin participants of the HELIUS study (Amsterdam, The Netherlands). We derived principal components (PCs) from the metabolites. Linear regression was used to assess differences in PCs and individual metabolite concentrations, and their age-trends between the groups by sex. We adjusted for BMI and intake of fat and total energy. Mean age was 44.8 (SD 13.3) years. Many metabolite concentrations were higher among South-Asian Surinamese participants compared to Dutch participants; amino acids in women, and both acylcarnitines and amino acids in men. Metabolite levels increased similarly with age in both ethnic groups. Results remained similar after adjustment. Ethnic differences in metabolite concentrations suggest that fatty acid and amino acid metabolism are more dysregulated among South-Asian Surinamese compared to Dutch from a young age. During adulthood metabolites increase similarly in both ethnic groups

神戸大学大学教育推進機構開設記念公開シンポジウム:学生の力を活かす教育システムをめざして

textabstractWe present a two-week old girl who was diagnosed with cerebrotendinous xanthomatosis (CTX), an inborn error of bile acid synthesis, after a diagnostic workup for convulsions which were shown to be caused by a parechovirus encephalitis. The diagnosis of CTX was confirmed with CYP27A1 mutation analysis. She was started on chenodeoxycholic acid (CDCA) supplementation, which inhibits cholestanol production through a feedback mechanism, at the advised dosage of 15 mg/kg/day. Within 6 weeks, she developed jaundice with hepatomegaly. CDCA supplementation was stopped after which liver size and function rapidly normalised. CDCA supplementation was then restarted and maintained at 5 mg/kg/day. Cholestanol, liver enzymes and total bilirubin were frequently monitored in the patient, who is now 2.8 years of age, and have remained within normal range. Her psychomotor development has been normal. Conclusion: adequate metabolic control was achieved in an infant with CTX with CDCA supplementation at a dosage of 5 mg/kg/day and was well tolerated. CDCA supplementation at 15 mg/kg/day seems hepatotoxic in infants and should not be used. This is relevant in view of the possible inclusion of CTX in newborn screening programs in the near future.What is Known:• Cerebrotendinous xanthomatosis (CTX), an inborn error of bile acid synthesis, is a progressive neurological disorder.• Symptoms of CTX can be halted, and likely prevented, with chenodeoxycholic acid (CDCA) supplementation, making CTX a good candidate for newborn screening.What is New:• CDCA supplementation at the advised dosage of 15 mg/kg/day in children seems hepatoxic in infants with CTX.• Adequate metabolic control in an infant with CTX was achieved with CDCA supplementation at 5 mg/kg/day and well tolerated

The dynamics of cardiolipin synthesis post-mitochondrial fusion

AbstractAlteration in mitochondrial fusion may regulate mitochondrial metabolism. Since the phospholipid cardiolipin (CL) is required for function of the mitochondrial respiratory chain, we examined the dynamics of CL synthesis in growing Hela cells immediately after and 12h post-fusion. Cells were transiently transfected with Mfn-2, to promote fusion, or Mfn-2 expressing an inactive GTPase for 24h and de novo CL biosynthesis was examined immediately after or 12h post-fusion. Western blot analysis confirmed elevated Mfn-2 expression and electron microscopic analysis revealed that Hela cell mitochondrial structure was normal immediately after and 12h post-fusion. Cells expressing Mfn-2 exhibited reduced CL de novo biosynthesis from [1,3-3H]glycerol immediately after fusion and this was due to a decrease in phosphatidylglycerol phosphate synthase (PGPS) activity and its mRNA expression. In contrast, 12h post-mitochondrial fusion cells expressing Mfn-2 exhibited increased CL de novo biosynthesis from [1,3-3H]glycerol and this was due to an increase in PGPS activity and its mRNA expression. Cells expressing Mfn-2 with an inactive GTPase activity did not exhibit alterations in CL de novo biosynthesis immediately after or 12h post-fusion. The Mfn-2 mediated alterations in CL de novo biosynthesis were not accompanied by alterations in CL or monolysoCL mass. [1-14C]Oleate incorporation into CL was elevated at 12h post-fusion indicating increased CL resynthesis. The reason for the increased CL resynthesis was an increased mRNA expression of tafazzin, a mitochondrial CL resynthesis enzyme. Ceramide-induced expression of PGPS in Hela cells or in CHO cells did not alter expression of Mfn-2 indicating that Mfn-2 expression is independent of altered CL synthesis mediated by elevated PGPS. In addition, Mfn-2 expression was not altered in Hela cells expressing phospholipid scramblase-3 or a disrupted scramblase indicating that proper CL localization within mitochondria is not essential for Mfn-2 expression. The results suggest that immediately post-mitochondrial fusion CL de novo biosynthesis is “slowed down” and then 12h post-fusion it is “upregulated”. The implications of this are discussed

The influence of a maternal vegan diet on carnitine and vitamin B2 concentrations in human milk

BackgroundThe maternal diet greatly influences the nutritional composition of human milk. With the rise of vegan diets by lactating mothers, there are concerns about the nutritional adequacy of their milk. Two important nutrients, vitamin B2 and carnitine, are mostly ingested via animal products.ObjectiveWe investigated the influence of a vegan diet on the vitamin B2 and carnitine concentrations in milk and serum of lactating women.MethodsIn this case–control study, 25 lactating mothers following an exclusive vegan diet were comparted to 25 healthy lactating mothers with an omnivorous diet without use of supplements. High-performance liquid chromatography and liquid chromatography–tandem mass spectrometry were used to measure vitamin B2 and carnitine concentrations, respectively. A linear regression model was used to determine differences in human milk and serum concentrations between study groups.ResultsVitamin B2 concentrations in human milk and serum did not differ between study groups. While the human milk free carnitine (C0) and acetyl carnitine (C2) concentrations did not differ between study groups, serum carnitine concentrations were lower in participants following a vegan diet than in omnivorous women (p < 0.0001).ConclusionA maternal vegan diet did not affect human milk concentration of vitamin B2 and carnitine. Breastfed infants of mothers following an exclusive vegan diet therefore are likely not at increased risk of developing a vitamin B2 or carnitine deficiency

Cardiolipin provides an essential activating platform for caspase-8 on mitochondria

Cardiolipin is a mitochondria-specific phospholipid known to be intimately involved with apoptosis. However, the lack of appropriate cellular models to date restricted analysis of its role in cell death. The maturation of cardiolipin requires the transacylase tafazzin, which is mutated in the human disorder Barth syndrome. Using Barth syndrome patient-derived cells and HeLa cells in which tafazzin was knocked down, we show that cardiolipin is required for apoptosis in the type II mitochondria-dependent response to Fas stimulation. Cardiolipin provides an anchor and activating platform for caspase-8 translocation to, and embedding in, the mitochondrial membrane, where it oligomerizes and is further activated, steps that are necessary for an efficient type II apoptotic response

Contributions of amino acid, acylcarnitine and sphingolipid profiles to type 2 diabetes risk among South-Asian Surinamese and Dutch adults

Introduction: People of South Asian origin are at high risk of type 2 diabetes (T2D), but the underpinning mechanisms are not fully understood. We determined ethnic differences in acylcarnitine, amino acid and sphingolipid concentrations and determined the associations with T2D. Research design and methods: Associations between these metabolites and incident T2D among Dutch and South-Asian Surinamese were determined in participants from the Healthy Life in an Urban Setting (HELIUS) study (Amsterdam, the Netherlands) using Prentice-weighted Cox regression. The HELIUS study includes 95 incident T2D cases and a representative subcohort of 700 people from a cohort of 5977 participants with a mean follow-up of 4 years. Results: Concentrations of acylcarnitines were comparable between both ethnic groups. Amino acid and lactosylceramide concentrations were higher among South-Asian Surinamese than Dutch (eg, isoleucine 65.7 (SD 16.3) vs 60.7 (SD 15.6) µmol/L). Ceramide concentrations were lower among South-Asian Surinamese than Dutch (eg, Cer d18:1 8.48 (SD 2.04) vs 9.08 (SD 2.29) µmol/L). Metabolic dysregulation preceded T2D without evidence for a multiplicative interaction by ethnicity. Most amino acids and (dihydro)ceramides were associated with increased risk (eg, Cer d18:1 HR 2.38, 95% CI 1.81 to 3.12) while acylcarnitines, glycine, glutamine and lactosylceramides were associated with decreased risk for T2D (eg, LacCer d18:2 HR 0.56, 95% CI 0.42 to 0.77). Conclusions: Overall, these data suggest that the disturbances underlying amino acid and sphingolipid metabolism may be predictive of T2D risk in populations of both South Asian and European background. These observations may be used as starting point to unravel the underlying metabolic disturbances

Коммутационные перенапряжения в сетях высокого напряжения

Исследование коммутационных перенапряжений в высоковольтных сетях. В работе проводилось моделирование коммутационных перенапряжений в двух расчётных программах. Был произведён подбор защитного оборудования.Research of surge overvoltages in high-voltage grids. The simulation of surge overvoltages in two computational programs was carried out. A selection of protective equipment was made

Enantiomer-specific pharmacokinetics of D,L-3-hydroxybutyrate:Implications for the treatment of multiple acyl-CoA dehydrogenase deficiency

D,L-3-hydroxybutyrate (D,L-3-HB, a ketone body) treatment has been described in several inborn errors of metabolism, including multiple acyl-CoA dehydrogenase deficiency (MADD; glutaric aciduria type II). We aimed to improve the understanding of enantiomer-specific pharmacokinetics of D,L-3-HB. Using UPLC-MS/MS, we analyzed D-3-HB and L-3-HB concentrations in blood samples from three MADD patients, and blood and tissue samples from healthy rats, upon D,L-3-HB salt administration (patients: 736-1123 mg/kg/day; rats: 1579-6317 mg/kg/day of salt-free D,L-3-HB). D,L-3-HB administration caused substantially higher L-3-HB concentrations than D-3-HB. In MADD patients, both enantiomers peaked at 30 to 60 minutes, and approached baseline after 3 hours. In rats, D,L-3-HB administration significantly increased Cmax and AUC of D-3-HB in a dose-dependent manner (controls vs ascending dose groups for Cmax: 0.10 vs 0.30-0.35-0.50 mmol/L, and AUC: 14 vs 58-71-106 minutes*mmol/L), whereas for L-3-HB the increases were significant compared to controls, but not dose proportional (Cmax: 0.01 vs 1.88-1.92-1.98 mmol/L, and AUC: 1 vs 380-454-479 minutes*mmol/L). L-3-HB concentrations increased extensively in brain, heart, liver, and muscle, whereas the most profound rise in D-3-HB was observed in heart and liver. Our study provides important knowledge on the absorption and distribution upon oral D,L-3-HB. The enantiomer-specific pharmacokinetics implies differential metabolic fates of D-3-HB and L-3-HB

Monitoring phenylalanine concentrations in the follow-up of phenylketonuria patients:An inventory of pre-analytical and analytical variation

Background: Reliable measurement of phenylalanine (Phe) is a prerequisite for adequate follow-up of phenylketonuria (PKU) patients. However, previous studies have raised concerns on the intercomparability of plasma and dried blood spot (DBS) Phe results. In this study, we made an inventory of differences in (pre-)analytical methodology used for Phe determination across Dutch laboratories, and compared DBS and plasma results. Methods: Through an online questionnaire, we assessed (pre-)analytical Phe measurement procedures of seven Dutch metabolic laboratories. To investigate the difference between plasma and DBS Phe, participating laboratories received simultaneously collected plasma-DBS sets from 23 PKU patients. In parallel, 40 sample sets of DBS spotted from either venous blood or capillary fingerprick were analyzed. Results: Our data show that there is no consistency on standard operating procedures for Phe measurement. The association of DBS to plasma Phe concentration exhibits substantial inter-laboratory variation, ranging from a mean difference of −15.5% to +30.6% between plasma and DBS Phe concentrations. In addition, we found a mean difference of +5.8% in Phe concentration between capillary DBS and DBS prepared from venous blood. Conclusions: The results of our study point to substantial (pre-)analytical variation in Phe measurements, implicating that bloodspot Phe results should be interpreted with caution, especially when no correction factor is applied. To minimize variation, we advocate pre-analytical standardization and analytical harmonization of Phe measurements, including consensus on application of a correction factor to adjust DBS Phe to plasma concentrations

Clinical and biochemical characterization of four patients with mutations in ECHS1

Short-chain enoyl-CoA hydratase (SCEH, encoded by ECHS1) catalyzes hydration of 2-trans-enoyl-CoAs to 3(S)-hydroxy-acyl-CoAs. SCEH has a broad substrate specificity and is believed to play an important role in mitochondrial fatty acid oxidation and in the metabolism of branched-chain amino acids. Recently, the first patients with SCEH deficiency have been reported revealing only a defect in valine catabolism. We investigated the role of SCEH in fatty acid and branched-chain amino acid metabolism in four newly identified patients. In addition, because of the Leigh-like presentation, we studied enzymes involved in bioenergetics. Metabolite, enzymatic, protein and genetic analyses were performed in four patients, including two siblings. Palmitate loading studies in fibroblasts were performed to study mitochondrial β-oxidation. In addition, enoyl-CoA hydratase activity was measured with crotonyl-CoA, methacrylyl-CoA, tiglyl-CoA and 3-methylcrotonyl-CoA both in fibroblasts and liver to further study the role of SCEH in different metabolic pathways. Analyses of pyruvate dehydrogenase and respiratory chain complexes were performed in multiple tissues of two patients. All patients were either homozygous or compound heterozygous for mutations in the ECHS1 gene, had markedly reduced SCEH enzymatic activity and protein level in fibroblasts. All patients presented with lactic acidosis. The first two patients presented with vacuolating leukoencephalopathy and basal ganglia abnormalities. The third patient showed a slow neurodegenerative condition with global brain atrophy and the fourth patient showed Leigh-like lesions with a single episode of metabolic acidosis. Clinical picture and metabolite analysis were not consistent with a mitochondrial fatty acid oxidation disorder, which was supported by the normal palmitate loading test in fibroblasts. Patient fibroblasts displayed deficient hydratase activity with different substrates tested. Pyruvate dehydrogenase activity was markedly reduced in particular in muscle from the most severely affected patients, which was caused by reduced expression of E2 protein, whereas E2 mRNA was increased. Despite its activity towards substrates from different metabolic pathways, SCEH appears to be only crucial in valine metabolism, but not in isoleucine metabolism, and only of limited importance for mitochondrial fatty acid oxidation. In severely affected patients SCEH deficiency can cause a secondary pyruvate dehydrogenase deficiency contributing to the clinical presentatio