The Experts below are selected from a list of 9009 Experts worldwide ranked by ideXlab platform
Helga Refsum - One of the best experts on this subject based on the ideXlab platform.
-
plasma Sulfur Amino Acids and risk of cerebrovascular diseases a nested case control study in the epic norfolk cohort
Stroke, 2021Co-Authors: Kathrine J Vinknes, Helga Refsum, C A P Turner, Kaytee Khaw, Nicholas J Wareham, Nita G Forouhi, Fumiaki ImamuraAbstract:Background and Purpose: B-vitamin supplements lower circulating concentrations of homocysteine and may reduce stroke incidence. Homocysteine concentrations are associated with the incidence of stro...
-
postprandial effects of a meal low in Sulfur Amino Acids and high in polyunsaturated fatty Acids compared to a meal high in Sulfur Amino Acids and saturated fatty Acids on stearoyl coa desaturase indices and plasma Sulfur Amino Acids a pilot study
BMC Research Notes, 2020Co-Authors: Thomas Olsen, Helga Refsum, C A P Turner, Bente Ovrebo, Nasser E Bastani, Kathrine J VinknesAbstract:The Sulfur Amino acid (SAA) cysteine is positively related, whereas polyunsaturated fatty Acids (PUFAs) are inversely related to activity of the lipogenic enzyme stearoyl-CoA desaturase (SCD). High SCD activity promotes obesity in animals, and plasma activity indices positively associates with fat mass in humans. SCD may thus be a target for dietary intervention with SAA restriction and PUFA enrichment with unknown potential benefits for body composition. We randomized ten healthy individuals to a meal restricted in SAAs and enriched with PUFAs (Cys/Metlow + PUFA) (n = 5) or a meal enriched in SAA and saturated fatty Acids (Cys/Methigh + SFA) (n = 5). We measured plasma SCD activity indices (SCD16 and SCD18) and SAAs response hourly from baseline and up to 4 h postprandial. SCD16 was unchanged whereas SCD18 tended to increase in the Cys/Metlow + PUFA compared to the Cys/Methigh + SFA group (ptime*group interaction = 0.08). Plasma concentrations of total cysteine fractions including free and reduced cysteine decreased in the Cys/Metlow + PUFA compared to the Cys/Methigh + SFA group (both ptime*group interaction < 0.001). In conclusion, a meal low in SAA but high in PUFAs reduced plasma cysteine fractions but not SCD activity indices. This pilot study can be useful for the design and diet composition of future dietary interventions that targets SCD and SAA. Trial registration ClinicalTrials.gov: NCT02647970, registration date: 6 January 2016
-
body mass index determines the response of plasma Sulfur Amino Acids to methionine loading
Biochimie, 2020Co-Authors: Amany K Elshorbagy, Helga Refsum, Ian GrahamAbstract:Abstract Evidence from human, animal and cellular studies suggests that high plasma total cysteine (tCys) is causally linked to human obesity, but determinants of population tCys variability are unknown. We hypothesized that tCys elevation in obesity may be mediated by an altered tCys response to intake of its precursor, methionine. We investigated whether BMI influences the change in plasma tCys, total homocysteine (tHcy) and total cysteinylglycine (tCysGly) 6h following a 100 mg/kg oral methionine load in 800 healthy subjects and 750 cardiovascular disease (CVD) cases. Methionine loading decreased tCys from mean 275 (95% CI, 273, 277) μmol/L to 253 (251,255) μmol/L. The decline in tCys was less in overweight (−8%) and obese (−6%) compared to normal weight (−9%) subjects, adjusting for age, gender and CVD (P-ANOVA = 0.006). Compared to normal weight subjects, individuals with obesity had a 2.8-fold likelihood (95% CI, 1.52, 5.01) of experiencing a rise (rather than decline), in tCys postload, after multiple adjustments. tCysGly also decreased postload, and the decline was similarly smaller in overweight (−18%) and obese (−15%) compared to normal weight (−21%) individuals (P-ANOVA
-
Amino acid changes during transition to a vegan diet supplemented with fish in healthy humans
European Journal of Nutrition, 2017Co-Authors: Amany K Elshorbagy, Fredrik Jerneren, Marianne Basta, Caroline Basta, C A P Turner, Maram Khaled, Helga RefsumAbstract:Purpose To explore whether changes in dietary protein sources can lower plasma branched-chain Amino Acids (BCAAs), aromatic Amino Acids and Sulfur Amino Acids (SAAs) that are often elevated in the obese, insulin-resistant state and in type 2 diabetes.
-
association of vitamin b12 folate and Sulfur Amino Acids with brain magnetic resonance imaging measures in older adults a longitudinal population based study
JAMA Psychiatry, 2016Co-Authors: Helga Refsum, David A Smith, Babak Hooshmand, Francesca Mangialasche, Gregoria Kalpouzos, Alina Solomon, Ingemar KareholtAbstract:Importance Vitamin B12, folate, and Sulfur Amino Acids may be modifiable risk factors for structural brain changes that precede clinical dementia.Objective To investigate the association of circula ...
Kathrine J Vinknes - One of the best experts on this subject based on the ideXlab platform.
-
plasma Sulfur Amino Acids and risk of cerebrovascular diseases a nested case control study in the epic norfolk cohort
Stroke, 2021Co-Authors: Kathrine J Vinknes, Helga Refsum, C A P Turner, Kaytee Khaw, Nicholas J Wareham, Nita G Forouhi, Fumiaki ImamuraAbstract:Background and Purpose: B-vitamin supplements lower circulating concentrations of homocysteine and may reduce stroke incidence. Homocysteine concentrations are associated with the incidence of stro...
-
postprandial effects of a meal low in Sulfur Amino Acids and high in polyunsaturated fatty Acids compared to a meal high in Sulfur Amino Acids and saturated fatty Acids on stearoyl coa desaturase indices and plasma Sulfur Amino Acids a pilot study
BMC Research Notes, 2020Co-Authors: Thomas Olsen, Helga Refsum, C A P Turner, Bente Ovrebo, Nasser E Bastani, Kathrine J VinknesAbstract:The Sulfur Amino acid (SAA) cysteine is positively related, whereas polyunsaturated fatty Acids (PUFAs) are inversely related to activity of the lipogenic enzyme stearoyl-CoA desaturase (SCD). High SCD activity promotes obesity in animals, and plasma activity indices positively associates with fat mass in humans. SCD may thus be a target for dietary intervention with SAA restriction and PUFA enrichment with unknown potential benefits for body composition. We randomized ten healthy individuals to a meal restricted in SAAs and enriched with PUFAs (Cys/Metlow + PUFA) (n = 5) or a meal enriched in SAA and saturated fatty Acids (Cys/Methigh + SFA) (n = 5). We measured plasma SCD activity indices (SCD16 and SCD18) and SAAs response hourly from baseline and up to 4 h postprandial. SCD16 was unchanged whereas SCD18 tended to increase in the Cys/Metlow + PUFA compared to the Cys/Methigh + SFA group (ptime*group interaction = 0.08). Plasma concentrations of total cysteine fractions including free and reduced cysteine decreased in the Cys/Metlow + PUFA compared to the Cys/Methigh + SFA group (both ptime*group interaction < 0.001). In conclusion, a meal low in SAA but high in PUFAs reduced plasma cysteine fractions but not SCD activity indices. This pilot study can be useful for the design and diet composition of future dietary interventions that targets SCD and SAA. Trial registration ClinicalTrials.gov: NCT02647970, registration date: 6 January 2016
-
plasma Sulfur Amino Acids and stearoyl coa desaturase activity in two caucasian populations
Prostaglandins Leukotrienes and Essential Fatty Acids, 2013Co-Authors: Kathrine J Vinknes, Helga Refsum, J M Dekker, Christian A Drevon, Eha Nurk, Giel Nijpels, Coen D A Stehouwer, Tom TeerlinkAbstract:In rats, dietary restriction of the cysteine precursor methionine suppresses hepatic stearoyl-CoA desaturase (SCD)-1 expression and activity, whereas cysteine supplementation reverses these effects. In 2 independent cohorts: Hordaland Health Study (HUSK; N=2021, aged 71-74y), Norway, and Hoorn study (N=686, aged 50-87y), Netherlands, we examined the cross-sectional associations of plasma Sulfur-containing compounds (SCC; methionine, S-adenosylmethionine, S-adenosylhomocysteine, homocysteine, cystathionine, total cysteine (tCys), glutathione and cysteinylglycine) with SCD-16 index (16:1n-7/16:0), estimated from fatty acid profiles of total plasma or serum lipids. Only tCys was consistently associated with SCD-16 index after adjustments for sex and age (HUSK: partial r=0.14; Hoorn: partial r=0.11, P<0.001 for both), and after further adjustments for other SCC, body fat, diet, exercise and plasma lipids (HUSK: partial r=0.07, P=0.004; Hoorn: partial r=0.12, P=0.013). Together with animal data showing an effect of dietary cysteine on SCD1, our results suggest a role for cysteine in SCD1 regulation in humans.
C A P Turner - One of the best experts on this subject based on the ideXlab platform.
-
plasma Sulfur Amino Acids and risk of cerebrovascular diseases a nested case control study in the epic norfolk cohort
Stroke, 2021Co-Authors: Kathrine J Vinknes, Helga Refsum, C A P Turner, Kaytee Khaw, Nicholas J Wareham, Nita G Forouhi, Fumiaki ImamuraAbstract:Background and Purpose: B-vitamin supplements lower circulating concentrations of homocysteine and may reduce stroke incidence. Homocysteine concentrations are associated with the incidence of stro...
-
postprandial effects of a meal low in Sulfur Amino Acids and high in polyunsaturated fatty Acids compared to a meal high in Sulfur Amino Acids and saturated fatty Acids on stearoyl coa desaturase indices and plasma Sulfur Amino Acids a pilot study
BMC Research Notes, 2020Co-Authors: Thomas Olsen, Helga Refsum, C A P Turner, Bente Ovrebo, Nasser E Bastani, Kathrine J VinknesAbstract:The Sulfur Amino acid (SAA) cysteine is positively related, whereas polyunsaturated fatty Acids (PUFAs) are inversely related to activity of the lipogenic enzyme stearoyl-CoA desaturase (SCD). High SCD activity promotes obesity in animals, and plasma activity indices positively associates with fat mass in humans. SCD may thus be a target for dietary intervention with SAA restriction and PUFA enrichment with unknown potential benefits for body composition. We randomized ten healthy individuals to a meal restricted in SAAs and enriched with PUFAs (Cys/Metlow + PUFA) (n = 5) or a meal enriched in SAA and saturated fatty Acids (Cys/Methigh + SFA) (n = 5). We measured plasma SCD activity indices (SCD16 and SCD18) and SAAs response hourly from baseline and up to 4 h postprandial. SCD16 was unchanged whereas SCD18 tended to increase in the Cys/Metlow + PUFA compared to the Cys/Methigh + SFA group (ptime*group interaction = 0.08). Plasma concentrations of total cysteine fractions including free and reduced cysteine decreased in the Cys/Metlow + PUFA compared to the Cys/Methigh + SFA group (both ptime*group interaction < 0.001). In conclusion, a meal low in SAA but high in PUFAs reduced plasma cysteine fractions but not SCD activity indices. This pilot study can be useful for the design and diet composition of future dietary interventions that targets SCD and SAA. Trial registration ClinicalTrials.gov: NCT02647970, registration date: 6 January 2016
-
Amino acid changes during transition to a vegan diet supplemented with fish in healthy humans
European Journal of Nutrition, 2017Co-Authors: Amany K Elshorbagy, Fredrik Jerneren, Marianne Basta, Caroline Basta, C A P Turner, Maram Khaled, Helga RefsumAbstract:Purpose To explore whether changes in dietary protein sources can lower plasma branched-chain Amino Acids (BCAAs), aromatic Amino Acids and Sulfur Amino Acids (SAAs) that are often elevated in the obese, insulin-resistant state and in type 2 diabetes.
Ida Vanessa Doederlein Schwartz - One of the best experts on this subject based on the ideXlab platform.
-
leptin concentrations and scd 1 indices in classical homocystinuria evidence for the role of Sulfur Amino Acids in the regulation of lipid metabolism
Clinica Chimica Acta, 2017Co-Authors: Soraia Poloni, Henk J Blom, Poli Mara Spritzer, Roberta Hack Mendes, Vânia Dalmeida, Kamila Castro, Fernanda Sperbludwig, Johanna Kugele, Sara Tucci, Ida Vanessa Doederlein SchwartzAbstract:Abstract Background We describe body composition, lipid metabolism and Stearoyl-CoA desaturase-1 (SCD-1) indices in patients with classical homocystinuria (HCU). Methods Eleven treated HCU patients and 16 healthy controls were included. Body composition and bone mineral density were assessed by dual X-ray absorptiometry. Sulfur Amino Acids (SAA) and their derivatives (total homocysteine, cysteine, methionine, S-adenosylmethionine, S-adenosylhomocysteine, and glutathione), lipids (free fatty Acids, acylcarnitines, triglycerides and lipoproteins), glucose, insulin, leptin, adiponectin, and isoprostanes were measured in plasma. Insulin resistance was evaluated by HOMA-IR. To estimate liver SCD-1 activity, SCD-16 [16:1(n − 7)/16:0] and SCD-18 [18:1(n − 9)/18:0] desaturation indices were determined. Results In HCU patients, SCD-16 index was significantly reduced (p = 0.03). A trend of an association of SCD-16 index with cysteine was observed (r = 0.624, p = 0.054). HCU patients displayed lower lean mass (p Conclusions We report alterations in leptin and SCD-1 in HCU patients. These results agree with previous findings from epidemiologic and animal studies, and support a role for SAA on lipid homeostasis.
-
Stearoyl-CoA Desaturase-1: Is It the Link between Sulfur Amino Acids and Lipid Metabolism?
Biology, 2015Co-Authors: Soraia Poloni, Henk J Blom, Ida Vanessa Doederlein SchwartzAbstract:An association between Sulfur Amino Acids (methionine, cysteine, homocysteine and taurine) and lipid metabolism has been described in several experimental and population-based studies. Changes in the metabolism of these Amino Acids influence serum lipoprotein concentrations, although the underlying mechanisms are still poorly understood. However, recent evidence has suggested that the enzyme stearoyl-CoA desaturase-1 (SCD-1) may be the link between these two metabolic pathways. SCD-1 is a key enzyme for the synthesis of monounsaturated fatty Acids. Its main substrates C16:0 and C18:0 and products palmitoleic acid (C16:1) and oleic acid (C18:1) are the most abundant fatty Acids in triglycerides, cholesterol esters and membrane phospholipids. A significant suppression of SCD-1 has been observed in several animal models with disrupted Sulfur Amino acid metabolism, and the activity of SCD-1 is also associated with the levels of these Amino Acids in humans. This enzyme also appears to be involved in the etiology of metabolic syndromes because its suppression results in decreased fat deposits (regardless of food intake), improved insulin sensitivity and higher basal energy expenditure. Interestingly, this anti-obesogenic phenotype has also been described in humans and animals with Sulfur Amino acid disorders, which is consistent with the hypothesis that SCD-1 activity is influenced by these Amino Acids, in particularly cysteine, which is a strong and independent predictor of SCD-1 activity and fat storage. In this narrative review, we discuss the evidence linking Sulfur Amino Acids, SCD-1 and lipid metabolism.
Yolande Surdinkerjan - One of the best experts on this subject based on the ideXlab platform.
-
metabolism of Sulfur Amino Acids in saccharomyces cerevisiae
Microbiology and Molecular Biology Reviews, 1997Co-Authors: Dominique Thomas, Yolande SurdinkerjanAbstract:Sulfur Amino acid biosynthesis in Saccharomyces cerevisiae involves a large number of enzymes required for the de novo biosynthesis of methionine and cysteine and the recycling of organic Sulfur metabolites. This review summarizes the details of these processes and analyzes the molecular data which have been acquired in this metabolic area. Sulfur biochemistry appears not to be unique through terrestrial life, and S. cerevisiae is one of the species of sulfate-assimilatory organisms possessing a larger set of enzymes for Sulfur metabolism. The review also deals with several enzyme deficiencies that lead to a nutritional requirement for organic Sulfur, although they do not correspond to defects within the biosynthetic pathway. In S. cerevisiae, the Sulfur Amino acid biosynthetic pathway is tightly controlled: in response to an increase in the amount of intracellular S-adenosylmethionine (AdoMet), transcription of the coregulated genes is turned off. The second part of the review is devoted to the molecular mechanisms underlying this regulation. The coordinated response to AdoMet requires two cis-acting promoter elements. One centers on the sequence TCACGTG, which also constitutes a component of all S. cerevisiae centromeres. Situated upstream of the Sulfur genes, this element is the binding site of a transcription activation complex consisting of a basic helix-loop-helix factor, Cbf1p, and two basic leucine zipper factors, Met4p and Met28p. Molecular studies have unraveled the specific functions for each subunit of the Cbf1p-Met4p-Met28p complex as well as the modalities of its assembly on the DNA. The Cbf1p-Met4p-Met28p complex contains only one transcription activation module, the Met4p subunit. Detailed mutational analysis of Met4p has elucidated its functional organization. In addition to its activation and bZIP domains, Met4p contains two regulatory domains, called the inhibitory region and the auxiliary domain. When the level of intracellular AdoMet increases, the transcription activation function of Met4 is prevented by Met30p, which binds to the Met4 inhibitory region. In addition to the Cbf1p-Met4p-Met28p complex, transcriptional regulation involves two zinc finger-containing proteins, Met31p and Met32p. The AdoMet-mediated control of the Sulfur Amino acid pathway illustrates the molecular strategies used by eucaryotic cells to couple gene expression to metabolic changes.
