Dietary sulfur amino acid restriction in humans with overweight and obesity: a translational randomized controlled trial.

BACKGROUND: Dietary sulfur amino acid restriction (SAAR) improves metabolic health in animals. In this study, we investigated the effect of dietary SAAR on body weight, body composition, resting metabolic rate, gene expression profiles in white adipose tissue (WAT), and an extensive blood biomarker profile in humans with overweight or obesity. METHODS: N = 59 participants with overweight or obesity (73% women) were randomized stratified by sex to an 8-week plant-based dietary intervention low (~ 2 g/day, SAAR) or high (~ 5.6 g/day, control group) in sulfur amino acids. The diets were provided in full to the participants, and both investigators and participants were blinded to the intervention. Outcome analyses were performed using linear mixed model regression adjusted for baseline values of the outcome and sex. RESULTS: SAAR led to a ~ 20% greater weight loss compared to controls (ß 95% CI - 1.14 (- 2.04, - 0.25) kg, p = 0.013). Despite greater weight loss, resting metabolic rate remained similar between groups. Furthermore, SAAR decreased serum leptin, and increased ketone bodies compared to controls. In WAT, 20 genes were upregulated whereas 24 genes were downregulated (FDR < 5%) in the SAAR group compared to controls. Generally applicable gene set enrichment analyses revealed that processes associated with ribosomes were upregulated, whereas processes related to structural components were downregulated. CONCLUSION: Our study shows that SAAR leads to greater weight loss, decreased leptin and increased ketone bodies compared to controls. Further research on SAAR is needed to investigate the therapeutic potential for metabolic conditions in humans. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT04701346, registered Jan 8th 2021, https://www. CLINICALTRIALS: gov/study/NCT04701346.

Targeting the sulfur-containing amino acid pathway in leukemia.

sulfur-containing amino acids have been reported to patriciate in gene regulation, DNA methylation, protein synthesis and other physiological or pathological processes. In recent years, metabolism-related molecules of sulfur-containing amino acids affecting the occurrence, development and treatment of tumors have been implicated in various disorders, especially in leukemia. Here, we summarize current knowledge on the sulfur-containing amino acid metabolism pathway in leukemia and examine ongoing efforts to target this pathway, including treatment strategies targeting (a) sulfur-containing amino acids, (b) metabolites of sulfur-containing amino acids, and (c) enzymes and cofactors related to sulfur-containing amino acid metabolism in leukemia. Future leukemia therapy will likely involve innovative strategies targeting the sulfur-containing amino acid metabolism pathway.

Dietary sulfur amino acid restriction in humans with overweight and obesity: Evidence of an altered plasma and urine sulfurome, and a novel metabolic signature that correlates with loss of fat mass and adipose tissue gene expression.

BACKGROUND: In animals, dietary sulfur amino acid restriction (SAAR) improves metabolic health, possibly mediated by altering sulfur amino acid metabolism and enhanced anti-obesogenic processes in adipose tissue. AIM: To assess the effects of SAAR over time on the plasma and urine SAA-related metabolites (sulfurome) in humans with overweight and obesity, and explore whether such changes were associated with body weight, body fat and adipose tissue gene expression. METHODS: Fifty-nine subjects were randomly allocated to SAAR (∼2 g SAA, n = 31) or a control diet (∼5.6 g SAA, n = 28) consisting of plant-based whole-foods and supplemented with capsules to titrate contents of SAA. Sulfurome metabolites in plasma and urine at baseline, 4 and 8 weeks were measured using HPLC and LC-MS/MS. mRNA-sequencing of subcutaneous white adipose tissue (scWAT) was performed to assess changes in gene expression. Data were analyzed with mixed model regression. Principal component analyses (PCA) were performed on the sulfurome data to identify potential signatures characterizing the response to SAAR. RESULTS: SAAR led to marked decrease of the main urinary excretion product sulfate (p < 0.001) and plasma and/or 24-h urine concentrations of cystathionine, sulfite, thiosulfate, H2S, hypotaurine and taurine. PCA revealed a distinct metabolic signature related to decreased transsulfuration and H2S catabolism that predicted greater weight loss and android fat mass loss in SAAR vs. controls (all pinteraction < 0.05). This signature correlated positively with scWAT expression of genes in the tricarboxylic acid cycle, electron transport and ß-oxidation (FDR = 0.02). CONCLUSION: SAAR leads to distinct alterations of the plasma and urine sulfurome in humans, and predicted increased loss of weight and android fat mass, and adipose tissue lipolytic gene expression in scWAT. Our data suggest that SAA are linked to obesogenic processes and that SAAR may be useful for obesity and related disorders. TRIAL IDENTIFIER: https://clinicaltrials.gov/study/NCT04701346.

Elemental sulfur concentration can be used as a rapid, reliable, and cost-effective predictor of sulfur amino acid content of soybean seeds.

In this study, we have examined the feasibility of using elemental sulfur content of soybean seeds as a proxy for the overall sulfur amino acid content of soybean seeds. Earlier, we have identified by high throughput ionomic phenotyping several high and low sulfur containing soybean lines from the USDA Soybean Germplasm Collection. Here, we measured the cysteine and methionine content of select soybean lines by high-performance liquid chromatography. Our results demonstrate that those soybean lines which had high elemental sulfur content also had a higher cysteine and methionine content when compared to soybean lines with low elemental sulfur. SDS-PAGE and immunoblot analysis revealed that the accumulation of Bowman Birk protease inhibitor and lunasin in soybean seeds may only be marginally correlated with the elemental sulfur levels. However, we found a positive correlation between the levels of trypsin and chymotrypsin inhibitor activities and elemental sulfur and sulfur amino acid content of the seeds. Thus, elemental sulfur content and/or protease inhibitor activity measurement can be utilized as a rapid and cost-effective method to predict the overall sulfur amino acid content of soybean seeds. Our findings will benefit breeders in their endeavors to develop soybean cultivars with enhanced sulfur amino acid content.

Homocysteine thiolactone and other sulfur-containing amino acid metabolites are associated with fibrin clot properties and the risk of ischemic stroke.

Homocysteine (Hcy) and Hcy-thiolactone (HTL) affect fibrin clot properties and are linked to cardiovascular disease. Factors that influence fibrin clot properties and stroke are not fully understood. To study sulfur-containing amino acid metabolites, fibrin clot lysis time (CLT) and maximum absorbance (Absmax) in relation to stroke, we analyzed plasma and urine from 191 stroke patients (45.0% women, age 68 ± 12 years) and 291 healthy individuals (59.7% women, age 50 ± 17 years). Plasma and urinary levels of sulfur-containing amino acid metabolites and fibrin clot properties were significantly different in stroke patients compared to healthy individuals. Fibrin CLT correlated with fibrin Absmax in healthy males (R2 = 0.439, P = 0.000), females (R2 = 0.245, P = 0.000), female stroke patients (R2 = 0.187, P = 0.000), but not in male stroke patients (R2 = 0.008, P = ns). Fibrin CLT correlated with age in healthy females but not males while fibrin Absmax correlated with age in both sexes; these correlations were absent in stroke patients. In multiple regression analysis in stroke patients, plasma (p)CysGly, pMet, and MTHFR A1298C polymorphism were associated with fibrin Absmax, while urinary (u)HTL, uCysGly, and pCysGly were significantly associated with fibrin CLT. In healthy individuals, uHTL and uGSH were significantly associated with fibrin Absmax, while pGSH, and CBS T833C 844ins68 polymorphism were associated with fibrin CLT. In logistic regression, uHTL, uHcy, pCysGly, pGSH, MTHFR C677T polymorphism, and Absmax were independently associated with stroke. Our findings suggest that HTL and other sulfur-containing amino acid metabolites influence fibrin clot properties and the risk of stroke.

Restricted intake of sulfur-containing amino acids reversed the hepatic injury induced by excess Desulfovibrio through gut-liver axis.

Diet is a key player in gut-liver axis. However, the effect of different dietary patterns on gut microbiota and liver functions remains unclear. Here, we used rodent standard chow and purified diet to mimic two common human dietary patterns: grain and plant-based diet and refined-food-based diet, respectively and explored their impacts on gut microbiota and liver. Gut microbiota experienced a great shift with notable increase in Desulfovibrio, gut bile acid (BA) levels elevated significantly, and liver inflammation was observed in mice fed with the purified diet. Liver inflammation and elevated gut BA levels also occurred in mice fed with the chow diet after receiving Desulfovibrio desulfuricans ATCC 29,577 (DSV). Restriction of sulfur-containing amino acids (SAAs) prevented liver injury mainly through higher hepatic antioxidant and detoxifying ability and reversed the elevated BA levels due to excess Desulfovibrio. Ex vivo fermentation of human fecal microbiota with primary BAs demonstrated that DSV enhanced production of secondary BAs. Higher concentration of both primary and secondary BAs were found in the gut of germ-free mice after receiving DSV. In conclusion, Restriction of SAAs in diet may become an effective dietary intervention to prevent liver injury associated with excess Desulfovibrio in the gut.

The effect of phencyclidine-mediated blockade of NMDA receptors in the early postnatal period on glutathione and sulfur amino acid levels in the rat brain as a potential causative factor of schizophrenia-like behavior in adulthood.

BACKGROUND: Phencyclidine, an NMDA receptor antagonist, is frequently used to model behavioral and neurochemical changes correlated with schizophrenia in laboratory animals. The present study aimed to examine the effects of repeated administration of phencyclidine during early postnatal development on the contents of glutathione and sulfur-containing amino acids, as well as the activity of antioxidant enzymes in the brain of 12-day-old rats, and schizophrenia-like symptoms in adulthood. METHODS: Male Sprague-Dawley pups were administered phencyclidine (10 mg/kg) or saline subcutaneously on the postnatal days p2, p6, p9 and p12. In 12-day-old pups, 4 h after the last dose of phencyclidine, the levels of glutathione, cysteine, methionine, and homocysteine, and the enzymatic activity of superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione reductase (GR) were measured in the frontal cortex, hippocampus, and striatum. In 70-72-day-old rats, schizophrenia-like symptoms were assessed using behavioral tests. RESULTS: Biochemical data showed that perinatal phencyclidine treatment significantly reduced glutathione and cysteine levels in all brain structures studied, methionine was diminished in the striatum, and homocysteine in both the frontal cortex and striatum. GR activity was increased in the frontal cortex while SODactivity was decreased in the hippocampus. Behaviorally, perinatal phencyclidine induced long-term deficits in social and cognitive function and a decrease in locomotor activity assessed as the time of walking. Finally, perinatal treatment with phencyclidine resulted in a significant reduction in body weight gain over time. CONCLUSION: Our research provides further evidence for the usefulness of the phencyclidine-induced neurodevelopmental model of schizophrenia for studying the pathogenesis of schizophrenia.

Protease em dietas com baixa proteína contendo farinha de Penas para codornas de corte / [Protease in low-protein diets for meat-type quails containing feather meal]

Objetivou-se avaliar a suplementação de protease em dietas com baixa proteína contendo farinha de penas (FP) sobre o desempenho e o rendimento de carcaça de codornas de corte. Foram utilizadas 240 codornas, machos, distribuídas em delineamento inteiramente ao acaso, em esquema fatorial 2x 3 (com e sem protease x 3 níveis de FP (0%, 5% e 10%)), totalizando seis tratamentos (dieta reduzida (DR) em 8% da exigência de proteína bruta e aminoácidos + 0% FP; DR + 5% FP; DR + 10% FP; DR + 0% FP + protease; DR + 5% FP + protease e DR + 10% FP + protease), quatro repetições de 10 codornas por parcela, nas fases de oito-21 dias e oito-35 dias de idade. Observou-se interação (P≤0,05) entre os níveis de FP e protease no ganho de peso de oito-21 dias. Os níveis de FP influenciaram (P≤0,05) o consumo de ração e o ganho de peso de oito-21 e oito-35 e a conversão alimentar de oito-21 dias. Verificou-se interação (P≤0,05) entre aprotease e a inclusão de FPpara o peso corporalaos 35 dias. Conclui-se que aFP pode ser utilizada em até 5% em dietas para codornas de corte semsuplementação comprotease.(AU)

The objective of this study was to evaluate protease supplementation in low-protein diets containing feather meal (FP) on the performance and carcass yield of meat-type quails. Twenty male quails were used in a completely randomized design, in a 2 x 3 factorial scheme (with and without protease x 3 FP levels (0, 5 and 10%)), totaling six treatments (Reduced diet (RD) in 8 % of the requirement of crude protein and amino acids + 0% FP; RD + 5% FP; RD + 10% FP; RD + 0% FP + protease; RD + 5% FP + protease and RD + 10% FP + protease), four replicates of 10 quails per plot, in the phases of 8-21 days and 8-35 days of age. Interaction (P≤0.05) was observed between FP and protease levels on weight gain over the period of 8-21 days. The levels of FP influenced (P≤0.05) the feed intake and the weight gain of 8-21 and 8-35 and the feed conversion ratio of 8-21 days. There was interaction (P≤0.05) between protease supplementation and FP inclusion for body weight at 35 days. It is concluded that FP can be used up to 5% in diets for meat-type quails without protease supplementation.(AU)

Suplementación con micronutrientes y efluvio telógeno posparto / No disponible

No disponible

Consumo dietético, variantes genéticas e relação com níveis sanguíneos de folato, ácido fólico não metabolizado e homocisteína após a fortificação mandatória de ácido fólico: estudo de base populacional - ISA - Capital / Dietary intake and genetic variants of folate and its relation to folate, unmetabolized folic acid and homocysteine blood concentrations after mandoty folic acid fortification population based study ISA-Capital

Em diversos países, inclusive no Brasil, a fortificação de alimentos com ácido fólico (AF) foi adotada como política pública de prevenção e combate à deficiência nutricional da vitamina, motivados principalmente pela redução da incidência dos defeitos do tubo neural. No período pós-fortificação observa-se tanto a evolução positiva do consumo e nível sérico da vitamina quanto a diminuição da concentração plasmática de homocisteína, e ainda, o aumento do ácido fólico não metabolizado na maioria desses países. Não se conhece ainda os efeitos biológicos do AFNM, no entanto, considera-se que o AFNM pode ser um fator relevante nas questões de segurança associadas com alto consumo de AF. Objetivo: Avaliar o consumo dietético e nível de folato, homocisteína e ácido fólico não metabolizado após a fortificação mandatória de alimentos com ácido fólico, e a interação com os polimorfismos envolvidos no metabolismo do folato e homocisteína. Metodologia: Os dados foram oriundos do estudo transversal de base populacional ISA Capital 2008 conduzido em uma amostra representativa de residentes do município de São Paulo, de ambos os sexos, e com idade acima de 14 anos. Coletou-se recordatórios alimentares de 24 horas e amostra de sangue em jejum de 12 horas para análises bioquímicas e moleculares. As análises estatísticas foram realizadas no programa STATA®, versão 13.0, com nível de significância de 5 por cento . Resultados: O estudo foi conduzido em 750 indivíduos, sendo 53,1 por cento mulheres e média de idade 40,7 (IC95 por cento 38,8-42,5) anos. A média de consumo e nível de folato foi de 375,8 (IC95 por cento 363,0-388,6) mcg/dia e 13 (IC95 por cento 12,0-13,9) ng/ml, respectivamente...

Food fortification is an important strategy in public health policy for controlling micronutrient malnutrition, and a major contributory factor in the eradication of micronutrients deficiencies. Motivated by the reduction in the occurrence of neural tube defects, countries worldwide, including Brazil, adopted food fortification with folic acid (FA). Folic acid fortification has increased dietary intakes of folic acid and folate status, but it is also associated with the presence of circulating FA. Although the metabolism and biological effects of circulating of folic acid are not well known, it may be a contributing factor in safety concerns associated with high oral doses of folic acid. Objective: To assess the folate intake and status, homocysteine and circulating FA after mandatory fortification with folic acid, and interaction with polymorphisms involved in 1-carbon metabolism. Material and Methods: Data were from 750 individuals aged > 14 years old who participated of a cross-sectional population-based survey in Sao Paulo City-Brazil. Fasting blood samples and information about food intake based on two measures of 24 hour food recall were collected. All analyses were carried out using STATA (version 13.0) and p-value <.05 was considered to be statistically significant in all tests. Results: Results were from 750 individuals...

Efeito dos níveis de metionina da dieta sobre o desempenho de poedeiras comerciais / Effect of methionine levels on performance of laying hens

Avaliou-se o efeito da adiçäo de níveis crescentes de DL-metionina na dieta sobre o desempenho de poedeiras comerciais. Foram utilizadas 960 poedeiras comerciais de linhagem Lohmann, distribuídas em quatro tratamentos, com quatro repetiçöes de 60 aves cada, em um delineamento experimental inteiramente ao acaso. O tratamento A foi como controle, sem adiçäo de DL-metionina, representando 0,29 por cento do aminoácido na raçäo. Para os tratamentos B, C e D as raçöes foram suplementadas com 0,03, 0,05 e 0,07 por cento de metionina, respectivamente, o que representou de 0,32, 0,34 e 0,36 por cento do aminoácido na raçäo. Foram avaliadas as seguintes características: produçäo de ovos (porcentagem), consumo de raçä (g), conversäo alimentar (kg/dz), peso dos ovos (g), massa do ovo (g) e espessura da casca do ovo (mm). Näo houve diferenças significativas (P<0,05) entre as médias para conversäo alimentar e espessura da casca do ovo. Entretanto, para produçäo de ovos, peso dos ovos, massa de ovo e consumo de raçäo, os tratamentos suplementados com metionina apresentaram melhores resultados quando comparados ao tratamento sem suplementaçäo

Efeito da suplementação de cisteína ou glutamina sobre o metabolisno dos aminoácidos sulfurados e glutationa de pacientes infectados pelo HIV nas condições de jejum e pós-sobrecarga de metionina / Effect of the cysteine or glutamine supplementation on the metabolism of sulphurated amino acids and glutathione state of HIV patients on fasting and after-methionine load

INTRODUÇÃO: Metionina (Met), cisteína (Cys), homocisteína (Hcy) e taurina (Tau) são os qautro aminoácidos sulfurados (AAS), mas apenas a Met e Cys são incorporadas em proteínas. Os três principais produtos dos AAS, glutationa, (GSH), Hcy e Tau influenciam, principalmente, as respostas inflamatória e imune. A Tau e GSH melhoram a inflamação, enquanto que a Hcy apresenta efeito oposto. Os pacientes HIV+ apresentam baixos níveis de GSH e outros nutrientes antioxidantes, mostrando relação direta entre Cys (e GSH) com células CD4 +. Não se conhece o mecanismo pelo qual as mudanças na ingestão dos AAS influenciam este fenômeno e as relações entre Hcy, doenças inflamatórias e alterações in vitro no comportamento das células imunes criou nota cautelar sobre a suplementação de dietas com AAS. OBJETIVOS: investigar as vias dos AAS em pacientes HIV+ nas condições de jejum e pós-sobrecarga de Met frente à dieta habitual (DH) isolada ou acompanhada da suplementação de Cys (NAC) ou glutamina (GIn). MÉTODOS: 12 pacientes HIV+ (6 M e 6 F, de 25 a 36 anos), sob tratamento anti-retroviral pelo esquema tríplice, sem infecções secundárias e 20 controles saudáveis (10 M e 10 F, 23-28 anos) foram randomicamente distribuídos para suplementação com NAC (N-acetilcisteína, 1g/d ou GIn (20 g/d) em estudo cruzado com 7 dias de dieta separados por uma semana de washout (Wo com DH). Amostras de sangue após jejum noturno de 10 a 12 horas foram coletadas antes (MO) e após (M1) cada regime dietético. A seguir, os indivíduos ingeriram metionina (100 mg/kg) com coletas de sangue após 2 e 4 horas para a determinação da área abaixo da curva (AAC)...

Methionine (Met), cysteine (Cys), homocysteine (Hcy), and, taurine (Tau) are the 4 sulfur-containing amino acids (SAA), but only Met and Cys are incorporated into proteins. The 3 major products of SAA, glutathione (GSH), Hcy and Tau influence, mainly, inflammatory and of immune responses. Tau and GSH ameliorate inflammation whereas Hcy has the opposite effect. HIV+ patients present low levelis of GSH and other antioxidants nutrients, showing a direct relationship between Cys (and GSH) with CD4+/ cells. How changes in SAA intake influence this phenomenon is unknown and the relationships among Hcy, inflammatory diseases, and in vitro alterations in immune cell behavior create a cautionary note about supplementation of diets with SAA. OBJECTIVE: To investigate SAA pathways in HIV+ patients on fast and Met-overload (Met-DL) states after taken diet habitual without (HD) or with supplements of Cys (NAC) or glutamine (Gln). METHOOS: 12 HIV+ (6M and 6F, 25-36 yrs old) patients under HAART without secondary infections and 20 healthy (10M and 10F, 23-28 yrs old) controls were randomly assigned to either NAC (N-acetylcysteine, 1g/d) or Gln (20g/d) diets, in a 7-day diet crossover design, separated by a 7-day washout (with HD) period. Blood samples were drawn after overnight fast before (MO) and after each dietary treatments (M1) for the resting measurements. Immediately after blood sampling ali subjects started the Met-DL by ingesting at once 100 mg Met/kg BW and having the blood draw after 2 and 4 hours for the area under the curve (AUC) determination. At MO both groups were assessed for anthropometry (BMI, kg/m2), glomerular (plasma urea and creatinina) and hepatocellular (plasma γGT activity) funetions, nutritional (albumin, calcium, folic acid and vitamin B12) and antioxidant (uric acid, GSH, GSSG, Hey) states, glucose, lipids (triglycerides and cholesterol fractions) and SAA, serine (Ser), glyeine (Gly), glutamate (Glu) and Gln. The HIV+ group was characterized also by viral load, CD4+ and CD8+ counts. The statistical comparisons between groups and among diets showed group homogeneity for 8MI, albumin, calcium, vitamin B12, Hey, HDL-cholesterol, urea and creatinine. The patients presented higher values of glucose, triglycerides, γ-GT, LDL-cholesterol, and GSSG along with lower concentrations of uric acid, GSH and all but Hcy amino acids. The Met-OL equalized (Δ values) the groups for Met, Hcy, Tau and Gln. NAC and Gln diets led the HIV+ group to a higher concentrations of GSH (NAC > Gln) by acting differently on its precursors: Gly (Gln > NAC) and Cys (NAC > Gln), resulting similar consumption of Ser and production of Tau. Both diets reduced GSSG/GSH (NAC > Gln) and only NAC increased (6 x) Hey. The later was worsened by Met-OL. Thus HIV+ results in multiple deficiencies of vitamins and amino acids leading to lower levels of GSH and higher GSSG/GSH ration. The main problems of lower formation of Cys and low ineorporation of Cys and Gly into GSH were greatly solved by giving Met, NAC and Gln to the patients, hence remaining the drawback of increasing Hcy with Met or NAC supplements.

Bases metabólicas da suplementação de cisteína / Metabolic Basis of supplemental cysteine / Metabólicas Bases de cisteína suplementaria

A cisteína (Cys) é um aminoácido sulfurado produzido, endogenamente, a partir da transulfuração da homocisteína. É limitante da síntese da glutationa, principal antioxidante (peroxidase) solúvel no citosol e maior fonte sulfurada endógena. Adicionalmente, a Cys origina a taurina (Tau) com papel neurotransmissor, inativador de ácidos biliares, osmolito intracelular e agente antioxidante intrafagocitário. Apenas o fígado, pãncreas e rins formam Cys a partir da metionina (Met). Nos demais tecidos, a principal fonte de Cys é a sua concentração plasmática ou as de GSH e GSSG (desde que a célula contenha y-glutamil transpeptidase e dipeptidase). A Cys (SH) é instável e se oxida facilmente a cistina (S-S), forma predominante no plasma. As células desprovidas de redutase, como os linfócitos, não convertem a Cis (S-S) a Cys (SH) e tornam-se dependentes da Cys gerada por outras células sanguíneas ou da Cys plasmática. A Cys ativa a proliferação celular e as funções de quimiotaxia, fagocitose e citoxicidade natural (de células malignas). A deficiência de Cys está associada não apenas aos menores níveis de GSH e menor defesa antioxidante, mas também à diminuição de glutamina e consequente deficiência imunitária. Não há recomendações específicas para a Cys.A RDA para Met+Cys é de 17 mg/g...

The cysteine (Cys) is a sulfur-containing amino acid produced endogenously from the transsulfuration of homocysteine. It is limiting the synthesis of glutathione, the main antioxidant (peroxidase) soluble in the cytosol and increased endogenous sulfur source. Additionally, Cys originates taurine (Tau) with paper neurotransmitter inactivation of bile acids, intracellular osmolyte and antioxidant agent intrafagocitário. Only liver, pancreas and kidneys form Cys from methionine (Met). In other tissues, the main source of Cys is its plasma concentration or GSH and GSSG (as long as the cell containing y-glutamyl transpeptidase and dipeptidase). The Cys (SH) is unstable and easily oxidized to cystine (SS), the predominant form in plasma. Cells devoid of reductase, such as lymphocytes, do not convert to Cys (SS) to Cys (SH) and become dependent on Cys generated by other blood cells or plasma Cys. The Cys active cell proliferation and functions of chemotaxis, phagocytosis, and natural cytotoxicity (malignant cells). Cys deficiency is associated not only with lower levels of GSH and lower antioxidant defense, but also to the decrease of glutamine and subsequent immune deficiency. There are no specific recommendations for Cys.A for Met + Cys RDA is 17 mg / g...

Aminoácidos plasmáticos en pacientes con neuropatía epidémica diagnósticados en Cuba / Plams amino acids in patients to whom epidemic neuropathy was diagnosed in Cuba

En los últimos años los estudios en pacientes con neuropatías han reveladocambios bioquímicos importantes que han explicado la pérdida de la visión por lesiones del nervio óptico con desmielización al nivel de la zona axial del nervio y en la cual los aminoácidos azufrados desempeñan un importante papel metabólico. Este estudio se encaminó a determinar la concentración plasmática de aminoácidos en pacientes con neuropatía epidémica diagnósticados en Cuba. Se encontró que la concentración plasmática de aminoácidos azufrados no cambió respecto al grupo control, por lo que creemos que el factor tóxico tenga un papel primordial. Sin embargo, se encontraron variaciones importantes en un grupo de aminoácidos que pensamos pueda deberse a cambios metabólicos de carácter nutricional que generalmente acpmpañan a esta enfermedad

Metabolismo de la homocisteína y riesgo de enfermedades cardiovasculares: Importancia del estado nutricio en ácido fólico, vitaminas B6 y B12 / Metabolism of homocysteine and risk of cardiovascular diseass: Importance of folic acid, vitamins B6 and B12 nutritional status

La homocisteína es un aminoácido azufrado que se sintetiza en el organismo a partir de la metionina. Este compuesto puede seguir dos rutas es su metabolismo, la de remetilación y la de transulfuración. La primera da lugar a la regeneración de metionina y la segunda a la formación de cisteína. Debido a su rápida utilización metabólica, este aminoácido se encuentra en bajas concentraciones en el plasma. La homocisteína circula en la sangre como tiol puro en bajas concentraciones y la mayoría se encuentra como disulfuro libre unido a residuos de cisteína de las proteínas. Sin embargo, en el caso de defectos genéticos en alguna de las enzimas del metabolismo de la homocistéina o de deficiencia nutricia de ácido fólico, vitamina B6 y B12, cuyas formas coenzimáticas se requieren para la utilización de homocisteína, se produce una elevación significativa de la concentración de este aminoácido en plasma asociado a un incremento en el desarrollo de enfermedades cardiovasculares. En base a estudios clínicos y epidemiológicos en la actualidad se considera la concentración de homocisteína en plasma como un factor independiente de riesgo de desarrollo de enfermedades aterotrombóticas y cardiovasculares. En la presente revisión se describe el metabolismo de la homocisteína, y la evidencia epidemiológica que muestra la asociación de la homocisteína con la incidencia de enfermedades cardiovasculares, así como valores de referencia. Se indican los mecanísmos a través de los cuales este aminoácido azufrado produce daño vascular. Finalmente, se dan algunas recomendaciones para el tratamiento nutricio de pacientes con hiperhomocisteinemia.

Hiperhomocisteinemia y preeclampsia: una combinación con grave riesgo vascular. Revisión bibliográfica y presentación de caso clínico / Hyperhomocysteinemia and preeclampsia: a combination with acute vascular risk

Dos tercios de los episodios de enfermedad vascular pueden atribuirse a factores de riesgo vasculares, ambientales y hereditarios. Un factor de riesgo independiente sería el aumento de homocisteína. Hoy se cuestiona si la hiperhomocisteinemia es causa de aterosclerosis y si su disminución reduce el riesgo de enfermedad cardiovascular. La prevalencia de hiperhomocisteinemia ha sido estimada en un 5 por ciento de la población general y en un rango de 13-47 por ciento en pacientes con enfermedad arteriosclerótica. Aunque la homocisteinuria fue descripta en 1962 los reportes en el mundo coinciden en que el diagnóstico es muchas veces erróneo o tardío. ¿Por qué el diagnóstico de la homocisteinuria es problemático?. En primer lugar la homocisteinuria es una patología rara y otros diagnósticos son considerados antes. Secundariamente hay problemas técnicos para la medición de la concentración de aminoácidos sulfuros en los fluidos. La ausencia de tratamiento de esta patología conduce al riesgo de: enfermedad coronaria, enfermedad cerebrovascular y tromboembolismo. Fue hallado que altos niveles de homocisteína en circulación materna o fetal se asocia con enfermedad vascular placentaria con el riesgo de preeclampsia en la madre y/o retardo del crecimiento intrauterino (RCIU) en el feto. Se encontró niveles más altos de homocisteína en embarazos complicados por preeclampsia. Los resultados apoyan que la hiperhomocisteinemia puede ser un marcador de riesgo para enfermedad vascular placentaria y preeclampsia materna. El interés de esta presentación es estimar si la relación entre preeclampsia e hiperhomocisteinemia constituye un factor predictor de riesgo vascular materno y/o fetal.

Influencia del tratamiento enzimático sobre la calidad de la proteína del guisante / Influence of enzymatic treatment on the pea protein quality

Se ha estudiado la calidad de la proteína del guisante tras una hidrólisis enzimática con proteasa de Aspergillus saitoi. Dicho tratamiento se ha llevado a cabo con el objeto de mejorar su valor nutritivo, aumentar su digestibilidad y disminuir la presencia de antinutrientes propios del guisante. Para ello se ha analizado el contenido en proteína total, aminoácidos esenciales, inhibidor de la tripsina y se ha obtenido una imagen electroforética de la proteína. El tratamiento enzimático no varió significativamente el contenido de proteína total y aminoácidos esenciales, ni tampoco aumentó su digestibilidad in vitro. Sin embargo, redujo el contenido en inhibidor de la tripsina y mostró un mayor número de fracciones proteicas en su imagen electroforética, sobre todo cuando se adicionó 2-mercaptoetanol (AU)

Farinha de soja integral: aplicacao da metodologia da superficie de resposta para estudo de aspectos nutricionais. / Integral soy bean flour: use of a methodology of response surface for the study of nutritional aspects

Cotiledones de soja (Glycine max, L. Merril) da variedade Parana, foram processados por metodo hidrotermico, manipulando as condicoes de processamento, atraves de metodologia da superficie de resposta, para escolha de condicoes, que fornecam produto de melhor qualidade proteica. As variaveis de processamento utilizadas no delineamento experimental foram: tempo de hidratacao de 0 a 8h; tempo de escaldamento de 5 a 35 min. e tratamento quimico com bicarbonato de sodio (NaHCO3) de 0 a 0.5 g%. As farinhas de soja integrais obtidas foram submetidas a avaliacao da qualidade nutricional proteica atraves do teste de NPR (razao de proteina liquida) e aminoacidos sulfurados. O modelo matematico desenvolvido nao conseguiu distinguir entre os tratamento (p < 0.05) na regiao experimental estudada

Relacion entre la digestibilidad y el valor proteinico del frijol comun (Phaseolus vulgaris). / Relationship between digestibility and protein value of common bean (Phaseolus vulgaris)

Entre las limitaciones nutricionales importantes del frijol se encuentra la baja digestibilidad de su proteina y su deficiencia en aminoacidos azufrados. El analisis de la informacion presentada indico que en 57 muestras de diferente color (23 rojo, 21 negro, 10 blanco y 3 cafe), no existia ninguna relacion entre la digestibilidad de la proteina y su calidad medida como NPR. Sin embargo, los frijoles blancos demostraron ser de mayor digestibilidad que los de color negro, rojo y cafe.La mayor digestibilidad del frijol blanco, empero, no se traduce en mejor calidad proteinica en mezclas con cereales, en comparacion con el rojo y el negro, debido a que la proteina que da una mayor digestibilidad en los frijoles blancos es bastante deficiente en aminoacidos azufrados