Introdução: 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. Apenas 1,76 por cento da população apresentou deficiência de folato (<3ng/ml). Foi 5 detectado AFNM em 79,8 por cento da população com média plasmática de 2,4 (IC95 por cento 2,1-2,7) ng/ml. No modelo linear generalizado para previsão de AFNM, nível de folato (p<0,001), idade (p<0,001), tabagismo (p=0,002), raça (p<0,001) e concentrações de B6 (p<0,001), além disso, a interação de homozigotos e heterozigotos para a deleção de pares de base da DHFR e nível de folato (p=0,003) foram efeitos significantes. Tem-se um aumento relativo esperado de 3 por cento no AFNM se aumentarmos em 1 ng/ml o nível de folato médio, considerando fixas as demais variáveis do modelo. Conclusão: Nota-se baixa prevalência da deficiência da vitamina e alta prevalência dos níveis detectáveis de AFNM na população decorrente do aumento do nível de folato. Todavia, apesar do aparente sucesso da fortificação de alimentos com ácido fólico, a comunidade científica não é unânime na aprovação de políticas de fortificação mandatória e do uso indiscriminado de suplementos. Recomenda-se um monitoramento constante para evitar que a população seja exposta a altas doses da vitamina, e consequentemente, efeitos adversos à saúde. / Introduction: 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. Women accounted for 53.1 per cent of the population and average age was 40.7 (IC95 per cent 38.8-42.5) years. The overall mean folate intake and folate concentration were 375.8 (95 per cent CI: 363.0-388.6) mcg/day of DFE and 13 (95 per cent CI: 12-14) ng/mL, respectively. Only 1.76 per cent of 7 population had folate deficiency (<3 ng/mL). Circulating FA was detected in 79.8 per cent of the population with a mean concentration of 2.4 (95 per cent CI: 2.1-2.7) pmol/ml. Effects of total folate concentration (p<0.001), age (p<0.001), current smoker (p=0.002), race (p<0.000) and vitamin B6 (p<0.001) as well as interaction between folate concentration and 19-base pair deletion polymorphism in DHFR (p=0.003) were found in the model to predict the circulating FA. An increase of one ng/mL in folate concentrate was associated with increased of 3 per cent in circulating FA. Conclusions: There is low prevalence of folate deficiency and high prevalence of detectable levels of circulating FA the population. The fortification effectively increased folate status and folic acid intake, and had a notable influence on rankings of food contributors of folate intake. Although the success of folic acid fortification was observed in many countries, the scientific community is not unanimous in approval of mandatory fortification policies and the indiscriminate use of supplements. The monitoring is recommended to guarantee the safety of exposure to folic acid, and avoiding adverse health effects.

Homocystein (tHcy) gilt als unabhängiger kardiovaskulärer Risikofaktor und korreliert eng mit einer endothelialen Dysfunktion, welche nichtinvasiv mittels der flussinduzierten Vasodilatation (FMD) messbar ist. Experimentelle Hyperhomocysteinämie ist mit einer reduzierten Bioverfügbarkeit von endothelialen Stickstoffmonoxid (NO) bei gleichzeitig erhöhten Spiegeln des kompetetiven Inhibitors der NO-Biosynthese asymmetrisches Dimethylarginin (ADMA) assoziiert. In-vivo senkt eine Östrogenbehandlung neben tHcy auch die ADMA-Spiegel und verbessert signifikant die Endothelfunktion. Hinsichtlich ihrer Wirkung als selektive Östrogenrezeptormodulatoren wird angenommen, dass Phytoöstrogene, speziell Sojaisoflavone, ähnliche Effekte hervorrufen.<br><br> Innerhalb einer europäischen, multizentrischen, doppelblinden Interventionsstudie an 89 gesunden, postmenopausalen Frauen wurde der Einfluss von Sojaisoflavonen auf den Homocysteinmetabolismus, den Blutdruck und die in-vivo Endothelfunktion untersucht. Die cross-over Studie umfasste zwei achtwöchige Interventionsperioden, die von einer gleichlangen Wash-out-Phase unterbrochen waren. Die Zuteilung zum Isoflavon- (50 mg/d) oder Plazeboregime für die erste Interventionsphase erfolgte randomisiert. Endpunkterhebungen fanden jeweils in den Wochen 0 und 8 der Interventionsperioden statt.<br><br> Die renale Ausscheidung von Genistein, Daidzein und Equol war während der Isoflavonintervention signifikant erhöht (P>0,001). Die Phyoöstrogene hatten weder einen Effekt auf die tHcy-Konzentration (P=0,286), noch auf ADMA, Erythrozytenfolat und Vitamin B-12 (P>0,05) im Plasma. Während die Summe aus Nitrat und Nitrit (NOx), welche die NO-Bioverfügbarkeit reflektiert, im Verlaufe der Plazebobehandlung abfiel, wurde ein leichter Anstieg bei der Isoflavonsupplementation beobachtet (Delta Wo8-Wo0: -2,60 [-8,75; 2,25] vs. 1,00 [-6,65; 7,85] µmol/L P<0,001), was zu einem signifikanten Behandlungseffekt führte. Weiterhin wurde eine positive Korrelation zwischen ADMA und Vitamin B-12 gefunden (R=0,252; P=0,018). Die flussinduzierte Vasodilatation (P=0,716), ein Maß für die Endothelfunktion, blieb durch die Isoflavonbehandlung unbeeinflusst, obwohl sich diese über die Zeit insgesamt verbesserte (P>0,001). Bis auf einen marginalen Anstieg des systolischen Wertes (P=0,032) im Vergleich zur Plazebobehandlung blieb der Blutdruck während der Isoflavonintervention unverändert.<br><br> Im Gegensatz zu Östrogen übten Sojaisoflavone weder einen Einfluss auf die in-vivo Endothelfunktion noch auf die traditionellen und neuen kardiovaskulären Risikofaktoren den Blutdruck, tHcy und ADMA aus. Demzufolge ist der gesundheitliche Nutzen isolierter Isoflavone hinsichtlich einer Prävention hormonmangelbedingter Erkrankungen in gesunden postmenopausalen Frauen fraglich. / Homocysteine (tHcy) is a strong and independent risk factor for cardiovascular disease. Hyperhomocysteinemia contributes to endothelial dysfunction as assessed by flow-mediated vasodilation (FMD). The mechanisms by which homocysteine generates endothelial dysfunction remain incompletely understood although a growing body of data suggests that the bioavailability of nitric oxide (NO) is reduced. The principal competitive inhibitor of endothelial NO-synthase asymmetric dimethylarginine (ADMA) may play a central role in homocysteine related dysfunction as it is derived from homocysteine metabolism. Cardiovascular risk factor modification has suggested beneficial effects of estrogen on endothelial function by lowering homocysteine and ADMA levels. We hypothesize that phytoestrogens particular isoflavones act in a similar manner.<br><br> The effects of soy isoflavones on homocysteine metabolism and endothelial function were investigated within a multi-centre, double blind, cross-over intervention trial in 89 European postmenopausal women. Subjects consumed either fruit cereal bars with or without soy isoflavones (50 mg/d) for 8 weeks each with a 8 weeks washout period in between. Endpoint measurements were during both treatment phases at baseline and weeks 8, respectively. <br><br> Urinary phytoestrogens increased significantly after isoflavone intervention (P<0.001). Isoflavone supplementation did affect neither plasma total homocysteine (P=0.286) nor ADMA, vitamin B-12 or folate (P<0.05). Isoflavones had a favorable effect on NO-metabolism assessed by analysis of NO-metabolites (NOx) nitrite and nitrate. While NOx concentration significantly decreased during placebo there was a slight increase after isoflavone supplementation leading to a significant treatment difference (delta wk8-wk0: -2.60 [-8.75; 2.25] vs. 1.00 [-6.65; 7.85] µmol/L P<0.001). There was no association between total homocysteine and ADMA whereas a positive correlation was found for ADMA and vitamin B-12 (R=0.252; P=0.018). The endothelial function model did not demonstrate any difference between either treatment regime (P=0.716), although endothelial function assessed by flow-mediated vasodilation improved in general (P<0.001). A potential adverse effect was noted, with an elevation in systolic blood pressure (P=0.032) whereas diastolic blood pressure and mean arterial pressure remained unaffected.<br><br> Soy isoflavones did not have beneficial effects on endothelial function as well as on traditional and novel cardiovascular risk factors like plasma homocysteine, blood pressure and ADMA as observed for estrogen treatment. The health benefit of isolated isoflavones in healthy postmenopausal women is questionable.

Abnormalities in homocysteine metabolism have been suggested as risk factors for stroke and myocardial infarction. In retrospective studies, elevated levels of total plasma homocysteine (tHcy) and/or methylenetetrahydrofolate reductase (MTHFR) 677C&gt;T polymorphism have indicated an increase in risk. However, the fewer prospective studies have not been as conclusive. To further explore this, tHcy was studied in four prospective settings. The first was a prospective nested case-referent cohort within the Västerbotten Intervention Program (VIP) and WHO MONICA project on 312 ischemic and 60 haemorrhagic first-ever strokes. The aim was to study tHcy and its main genetic determinant MTHFR. Risk for haemorrhagic stroke increased exponentially through tHcy quartiles, independent of hypertension and BMI, and increased for MTHFR 677 CT and TT. MTHFR 1298A&gt;C appeared to be protective. In multivariate models, after adjustment for tHcy, BMI and hypertension, both tHcy and MTHFR remained as independent predictors for hemorrhagic stroke. Neither tHcy, nor the two MTHFR polymorphisms were significant predictors for ischemic strokes. The second was a prospective long-term follow-up study within the VIP and MONICA cohorts to determine whether a first-ever myocardial infarction (AMI) causes increased levels of tHcy. Fifty cases developing AMI after the first screening participated in a second screening (mean follow-up 8.5 years) with 56 matched referents. Increase in tHcy did not differ between cases and referents. tHcy was related to AMI at follow-up, but not at baseline and no longer significant after adjusting for creatinine and albumin. The third was a method study to determine if cystatin C, creatinine, albumin and other lipoprotein risk markers of cardiovascular disease could be analysed in Stabilyte™ plasma stored at -80°C. It was found to be suitable for all analyses tested and using this tube would simplify sampling for epidemiological studies. The fourth study was a prospective longitudinal long-term study of 735 subjects (340 men and 395 women, age 25-64 at first screening), participating in two MONICA screenings nine years apart, who donated blood in Stabilyte™ tubes to study change over time in tHcy and its determinants. We confirmed the age dependency in a cross sectional setting. In contrast, if followed longitudinally over time, no change in tHcy or in the prevalence of hyperhomocysteinemia was found. Cystatin C and creatinine increased, and albumin decreased. In multivariate models baseline levels of albumin, creatinine, cystatin C, and to some extent hs-CRP, were predictors of tHcy at follow-up but gender differences were seen. Age was not a major determinant of change in tHcy over nine years. In conclusion, tHcy and MTHFR are risk factors for first-ever haemorrhagic, but not ischemic stroke in a prospective setting. A first myocardial infarction does not cause an increase in tHcy. No long-term changes were seen in tHcy over a nine-year period in neither men, nor in women.

Cobalamin (vitamin B12) is one of several essential micronutrients needed by the human organism. Other important micronutritients, which interplay with vitamin B12, are folate and iron. During the last ten years, the attention has been drawn to different forms of neurological disorders supposed to be caused by vitamin B12 deficiency. Vitamin B12 deficiency states are common among elderly patients in primary health care and sometimes in hospital care, especially in geriatric practice. This is a study to define the cobalamin treatment traditions, among Swedish physicians in the period 1990 – 2000. The period was distinguished by an intense debate on the issue by the physicians, an increase of cobalamin consumption, and a shift from parenteral therapy towards oral high-dose therapy. It had been known that symptoms of cobalamin deficiency could start in the nervous system. This knowledge was reinforced by the application of homocysteine and methyl-malonic acid (MMA) in deficiency diagnosis. Introduction of homocysteine and MMA in deficiency diagnosis changed the view on deficiency prevalence, by identifying persons at risk to develop B12 deficiency prior to established symptoms. In this study, Swedish physicians are regarded mainly as receivers of communication about the markers homocysteine and MMA, and deficiency states of cobalamin and folate. The main senders were scientists from North America, Norway, Denmark, and Sweden. This study sets the senders and the receivers of cobalamin communication on a collegial level and quantifies and evaluates the feed-back from the receivers. The receivers, gen¬eral practitioners and geriatricians, appeared to be familiar with old knowledge and frontier concepts in the field. Thus, it is suggested that the increase of B12 prescriptions in Sweden 1990 – 2000 reflected an increased awareness of B12-associated clinical problems among the physicians managing the majority of deficiency patients, although a possible overconsumption of pharmaceutical drugs must be kept in mind.

¤@¡BRole of 5-thio-(2-nitrobenzoic acid)-capped gold nanoparticles in the sensing of chromium(VI): remover and sensor This study describes a simple, rapid method for sensing Cr(VI) using 5-thio-(2-nitrobenzoic acid) modified gold nanoparticles (TNBA-AuNPs) as a remover for Cr(III) and as a sensor for Cr(VI). We discovered that TNBA-AuNPs were dispersed in the presence of Cr(VI), whereas Cr(III) induced the aggregation of TNBA-AuNPs. Due to this phenomenon, TNBA-AuNPs can be used as a sorbent material for the removal of > 90% Cr(III), without removing Cr(VI). After centrifuging a solution containing Cr(III), Cr(VI), and TNBA-AuNPs, Cr(III) and Cr(VI) were separately present in the precipitate and supernatant. In other words, TNBA-AuNPs are capable of separating a mixture of Cr(III) and Cr(VI). The addition of ascorbic acid to the supernatant resulted in a reduction of Cr(VI) to Cr(III), driving the aggregation of TNBA-AuNPs. The selectivity of this approach is more than 1000-fold for Cr(VI) over other metal ions. The minimum detectable concentration of Cr(VI) was 1 £gM using this approach. Inductively coupled plasma mass spectrometry provided an alternative for the quantification of Cr(III) and Cr(VI) after a mixture of Cr(III) and Cr(VI) had been separated by TNBA-AuNPs. The applicability of this approach was validated through the analysis of Cr(VI) in drinking and tap water. ¤G¡BFluorescent Sensing of Total, Protein-bound, Free, and Oxidized Homocysteine in Plasma through the Combination of Tris(2-carboxyethyl)Phosphine Reduction, Fluorosurfactant-Capped Gold Nanoparticles Extraction, and o-Phthaldialdehyde Derivatization This study reports a simple, selective, and sensitive method for fluorescent detection of total, protein-bound, free, and oxidized homocysteine (HCys) using tris(2-carboxyethyl)phosphine (TCEP) as a reducing agent, fluorosurfactant-capped gold nanoparticles (FSN-AuNP) as a preconcentrating probe, and o-Phthaldialdehyde (OPA) as a derivatizing agent. TCEP was used to reduce the disulfide bonds of protein-bound and oxidized HCys. FSN-AuNPs were capable of extracting HCys from a complicated complex because the FSN capping layer can stabilize the AuNPs in a high-salt solution and inhibit non-specific adsorption. HCys was selectively derivatized with OPA in the absence of a nucleophile. By taking advantage of these features, the selectivity of the proposed system is greater than 100-fold for HCys and homocystine (HCys-HCys disulfide; diHCys) compared to any aminothiols. The limits of detection (LODs) for HCys and diHCys were 4.4 and 4.6 nM, respectively. Compared to other sensors, the proposed system provides an approximately 3-300-fold improvement in the detection of HCys. Different forms of plasma HCys were determined by varying the order of disulfide reduction with TCEP. The proposed system was successfully applied to determine the total, protein-bound, free, and oxidized HCys in plasma. To the best of our knowledge, the proposed system not only provides the first method for detecting various forms of plasma HCys, but also has the lowest LOD value for HCys when compared to other sensors.

Sulfur amino acids have critical function as intracellular redox buffers and maintain homeostasis in the external milieu by combating oxidative stress. Synthesis of glutathione (GSH) is regulated at a substrate level by cysteine, which is synthesized by homocysteine via the transsulfuration pathway. Oxidative stress and diminished glutathione pools play a sustained role in the pathogenesis of acute pancreatitis. One of the aims of this study was to experimentally address the temporal relationship between plasma sulfur amino acid levels in patients suffering from acute pancreatitis. The data indicated low concentration of cysteine initially, at levels similar to those of healthy controls. Glutathione was found reduced whilst cysteinyl-glycine and γ- glutamyl transpeptidase activity were increased in both mild and severe attacks. As the disease progressed, glutathione and cysteinyl-glycine were further increased in mild attacks and cysteine levels correlated with homocysteine and γ-glutamyl transpeptidase activity. The progress of severe attacks was associated with glutathione depletion, reduced γ-glutamyl transpeptidase activity and increased cysteinyl-glycine, that correlated with glutathione depletion. The corollary that ample supply of cysteine and cysteinly-glycine does not contribute towards glutathione synthesis in acute pancreatitis poses an important issue that merits resolution. Heightened oxidative stress and depletion of glutathione rationalized the progression of disease in severe attacks. An upsurge that reactive oxygen species can shift redox state of cells is determined by the ratio of the abundant redox couples reduced and oxidized glutathione (GSH: GSSG) in cell. The study reported a novel methodology for quantification of total oxidized glutathione (tGSSG) and total glutathione (tGSH) in whole blood using reverse phase high performance liquid chromatography. The novelty of the method is ascertained by the use of a mercaptan scavenger 1, methyl-2-vinyl-pyridinium trifluromethanesulfonate for the total oxidized glutathione determination. The results reported permit quantitation of tGSSG and tGSH and was applied to a control group. Finally, the study was also focussed in developing a liquid chromatography-mass spectrometric method to evaluate free and conjugated bile acids in patients suffering from various degrees of cholestatic-hepatobiliary disorders. The study reported low levels of ursodeoxycholic acid (UDCA) and slightly high levels of lithocholic acid (LCA). All the primary bile acids seem to be conjugated with glycine and taurine amino acid.

The low molecular weight (L.M.W.) thiol redox couple formed by γ-L-glutamyl-L-cysteinyl glycine, also called glutathione (reduced and oxidized), is present in most eukaryotes and a few species of bacteria. Glutathione plays a role in numerous cellular processes by providing a means of shuttling electrons to different enzymatic systems. As a result, thiol-dependent redox metabolic processes are highly coupled. Due to tight coupling of redox reactions, it is difficult to understand how changes in the concentration of glutathione would affect a specific glutathione-dependent process. Interestingly, only a small subset of bacteria encode the canonical enzyme for the biosynthesis of glutathione, namely γ-glutamyl cysteine synthetase (gshA gene product). The mechanisms by which glutathione-dependent processes are carried out in bacteria which do not have the genes for biosynthesis of glutathione or other L.M.W. thiols is not well understood. A genetic selection to restore a glutathione-dependent phenotype in E. coli, lacking the gene involved in first step of glutathione biosynthesis (gshA), was used to address how bacteria lacking gshA might substitute for glutathione. Genetic and biochemical analyses of the E. coli mutants isolated in the selection revealed a de novo pathway for biosynthesis of γ-glutamyl cysteine, the product formed normally by GshA. Additionally we found that the unnatural analogue of glutathione, γ-glutamyl homocysteine could also be formed by this pathway. Bioinformatic analysis suggested that bacteria lacking gshA may use these de novo pathways for biosynthesis of γ-glutamyl cysteine or γ-glutamyl homocysteine, which could serve as potential substitutes for glutathione. The engineering of de novo biosynthetic pathways for γ-glutamyl cysteine and γ-glutamyl homocysteine provided us a strategy for engineering a pathway for biosynthesis of another unnatural analogue of glutathione, β-aspartyl cysteine. Both γ-glutamyl homocysteine and β-aspartyl cysteine could potentially be used as orthologus redox couples in E. coli operating in parallel to glutathione to shuttle electrons to specific pathways which may thus be decoupled from glutathione availability. Glutathione-dependent enzymes that can use orthologous redox couples instead are biochemically isolated from network of other redox reactions in the cell and could be used to direct metabolic fluxes to specific pathways with high efficiencies. Towards this end, we show that glutathione transferase, a glutathione-dependent enzyme, can be engineered to use analogous thiols like γ-glutamyl cysteine as cofactors. / text

No description available.

Galectina-1 (Gal-1) pertence à família de lectinas que reconhecem -galactosídeos e pode ser expressa em vários tipos celulares, incluindo as células endoteliais e músculo liso. Esta lectina endógena possui propriedades imunomodulatórias e antiinflamatórias, dependentes de processos celulares, essenciais incluindo ativação, diferenciação, sobrevivência, fagocitose e adesão celular. Os eventos iniciais da lesão vascular são pouco conhecidos e, na literatura, são escassos os dados sobre a participação da Gal-1 nesses eventos. Portanto, neste trabalho, pretendeu-se avaliar a participação dessa lectina nos eventos iniciais da lesão vascular por hiperhomocisteinemia moderada induzida em camundongos. A dose padrão de 0,4g/Kg/dia de homocisteína-tiolactona foi administrada oralmente a camundongos selvagens (Gal-1+/+) e destituídos do gene da Gal-1 (Gal-1-/-), por diferentes tempos, causando uma elevação da concentração plasmática de homocisteína total, Este fato provocou alterações na reatividade vascular de contração na artéria aorta e de rolamento e adesão de leucócitos em vênulas mesentéricas. Foi detectada a presença da Gal-1 nas aortas de animais Gal-1+/+ em todos tempos de tratamento e no controle, observando, porém, um aumento dela no grupo tratados por 15 dias e, mais expressa em 24 horas (expressão protéica por Western blot e imunofluorescência e, gênica por Real Time PCR). Neste tempo, houve maiores alterações metabólicas significativas como triglicérides, LDL, colesterol total, glicose e de homocisteína. A análise da expressão das óxido nítrico sintases revelou não haver alterações para NOS induzida (iNOS) entre os grupos de animais Gal-1+/+ controle e tratados, nem mesmo em relação aos animais controles Gal-1-/-. Entretanto, o tratamento modulou a expressão da NOS endotelial (eNOS) nos animais Gal-1+/+, havendo uma redução da proteína para os tempos de 48 horas e 7dias (expressão protéica por imunohistoquímica - peroxidade e, gênica por RT-PCR). O tratamento não alterou a concentração plasmática de óxido nítrico (NO) em camundongos Gal-1+/+, mas foi detectada redução dos valores basais para animais Gal-1-/- e, uma redução com o tratamento por 15 dias. Portanto, foi verificado que a expressão de Gal-1 foi aumentada com o tratamento de Hcy-Taq nos tempos de 24 horas e 15 dias, onde se observam significativas e maiores alterações biológicas dos parâmetros de lesão vascular induzida pela hiperhomocisteinemia moderada analisadas: reatividade vascular, rolamento e adesão de leucócitos em vênulas mesentéricas, concentração de homocisteína plasmática, perfil lipídico e expressão da óxido nítrico sintase endotelial. / Galectin-1 (Gal-1) belongs to the lectin family of -galactosides-binding proteins and can be expressed by several cell types, including endothelial cells and vascular smooth cells. This endogenous lectin has immunological and anti-inflammatory properties dependent of essential cellular processes, including activation, differentiation, survival, phagocytosis and cell adhesion. There are few and inconclusive studies about the engagement of Gal-1 in vascular injury initial processes. Thus, this work was conducted to evaluate the engagement of Gal-1 in hyperhomocysteinemia-induced vascular injury. Wild type (Gal-1+/+) and Gal-1-knockout (Gal-1-/-) mice were fed with 0,4g/Kg/day with thiolactone-homocysteine (D,L Hcy-T) for different times, provoking increased plasmatic total homocysteine levels. That has indicated alterations in aortic vasomotor responses and mesenteric venial leukocyte rolling and adhesion. Gal-1 was detected in aortic frozen section of Gal-1+/+ mice for all times of treatment with D,L Hcy-T, but more detected for aorta of 15 days treated animal group and, more expressed, for 24 hours ones (protein expression by Western blot and immunofluorescence and, genetic by Real Time PCR). Besides, at 24 hours of treatment, many metabolic alterations were observed: increased LDL, triglycerides, cholesterol, glucose and homocysteine levels. Expressions for nitric oxide sintases (NOS) showed no alteration for inducible NOS (iNOS) for Gal-1+/+ mice (treated or not), even for Gal-1-/- untreat mice. However, the treatment was able to modulate endothelial NOS (eNOS) decreasing the expression at 48 hours and 7 days treated animals group (protein expression by imunoperoxidase and, genetic by RT-PCR). Gal-1-/- mice have less circulating constitutive nitric oxide (NO) than Gal-1+/+ ones, and, the treatment has reduced these levels only for Gal-1-/- 15 days treated mice but not for Gal-1+/+ ones . This work, therefore, has shown that Gal-1 is always expressed by aortas. However, increased expression of Gal-1 at 24 hours and 15 days of treatment has been often correlated to biological alterations in the in hyperhomocysteinemia-induced vascular injury: aortic vasomotor responses, leukocyte rolling and adhesion in mesenteric venues, plasmatic homocysteine, lipid metabolites and NOS expression.

Made available in DSpace on 2014-12-17T14:13:32Z (GMT). No. of bitstreams: 1 MarcioLTA_Tese.pdf: 1453040 bytes, checksum: 7c0ed7c44a56eb54d2170012eedbfa04 (MD5) Previous issue date: 2009-11-27 / The imprecision of the frontier that separates those cognitive deficits inherent to the human physiological aging process from those which represent the early signs of nervous system degenerative pathologies ,very prevalent among the elderly, has brought attention to the need of studies aiming to establish clinical and/or laboratorial criteria to allow this differentiation. Elderly people living in poor and developing countries are frequently exposed to precarious socioeconomic conditions which facilitate the development of an array of pathologies which have metabolic and nutritional dysfunctions as the established or proposed etiological agents. The levels of certain micronutrients, such as the vitamins B12 and B9 (folic acid), and of some intermediary metabolites, such as homocysteine are being thought of as etiological factors and/or as biological markers of a group of alterations which affect the normal functioning of the nervous system with important reflexes upon cognitive performance. This study aims to investigate the influence of homocysteine, B12 vitamin and folic acid levels on the cognitive performance of the low income elderly population. This transversal study took place in Natal, Rio Grande do Norte State, Brazil, and involved 205 dwelling elderly people, users of the Programa de Sa?de da Fam?lia, a public healthcare program, maintained by the city s health authorities. A multidimensional questionnaire was used to assess the socio-demographic aspects and the overall health and nutrition conditions. The cognitive performance was measured by the use of the Portuguese version of the Mini Mental State Exam (MMSE). The serum levels of homocysteine, B12 vitamin and folic acid were determined by chemiluminescence. The association between the socio-demographic and serum levels of Hcy, B12 vitamin and folic acid was determined by multiple linear regression. Serum levels higher than 13.5 &#956;mol/l, indicative of hyperhomocysteinemia (HHcy), were found on 25.4% of the sample, being more prevalent in men (p<0.05). Deficitary levels of folic acid (<5ng/mol) and of B12 vitamin (<193 pg/ml) were found on 3.9% and 10.2% of the sample respectively. A negative correlation was found between cognitive performance with both age and HHcy and a positive correlation was found between cognitive performance and schooling. The isolated HHcy R2 values were an explanation to only 4% of the variance of the MMSE scores. However, when associated with schooling and age, this model explains about 25% of this association / A imprecis?o da fronteira que separa os d?ficits pr?prios do processo de envelhecimento fisiol?gico humano daqueles que representam os sinais precoces das patologias degenerativas de grande preval?ncia entre idosos, tem chamado a aten??o para a necessidade da produ??o de estudos voltados para o estabelecimento crit?rios cl?nicos e/ou laboratoriais que permitam essa diferencia??o. Idosos de popula??es de pa?ses pobres e/ou em desenvolvimento s?o freq?entemente expostos a condi??es socioecon?micas prec?rias prop?cias ao desenvolvimento de um conjunto de patologias, disfun??es metab?licas e nutricionais. Os n?veis de determinados micronutrientes e de alguns metab?litos intermedi?rios v?m sendo vistos como fatores etiol?gicos e como marcadores biol?gicos de um conjunto de altera??es que afetam a fun??o normal do sistema nervoso com reflexos importantes sobre o desempenho cognitivo. N?veis elevados de homociste?na (Hcy) e d?ficits nutricionais e /ou metab?licos da vitamina B12 e B9 (?cido f?lico) t?m sido apontados como preditores e/ou como fatores etiol?gicos de altera??es cognitivas. O objetivo desse estudo foi avaliar a influ?ncia dos n?veis de homociste?na, Vitamina B12 e ?cido f?lico no desempenho cognitivo de idosos de baixa renda. Este estudo transversal desenvolvido em Natal, Rio Grande do Norte, Brasil, incluiu 205 idosos n?o institucionalizados atendidos pelo Programa de Sa?de da Fam?lia da Secretaria Municipal de Sa?de do munic?pio. Um question?rio multidimensional foi utilizado para avaliar os aspectos sociodemogr?ficos e as condi??es gerais de sa?de e nutri??o. O desempenho cognitivo foi aferido utilizando-se a vers?o em portugu?s do Mini-Exame do Estado Mental (MEEM). Os n?veis s?ricos de homociste?na, Vitamina B12 e ?cido f?lico foram determinados por quimioluminesc?ncia. A associa??o entre as vari?veis sociodemogr?ficas e os n?veis s?ricos de Hcy Vitamina B12 e ?cido f?lico foi determinada atrav?s de regress?o linear m?ltipla. Valores s?ricos acima de 13,5 &#956;mol/l indicativos de hiperhomocisteinemia (HHcy) foram encontrados em 25,4% da amostra sendo mais prevalente em homens (p<0,05). N?veis deficit?rios de ?cido f?lico (<5ng/ml) e de Vitamina B12 (<193 pg/ml) foram encontrados em 3,9% e 10,2% dos indiv?duos respectivamente. O desempenho cognitivo mostrou uma correla??o negativa com a idade e a HHcy e positiva com a escolaridade. Os valores R2 da HHcy isolada explicaram apenas 4% da vari?ncia da pontua??o do MEEM. Contudo, quando associada escolaridade e idade, este modelo explica aproximadamente 25% desta associa??o.