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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

Total plasma homocysteine, vitamin supplementation and physical conditioning in men with coronary risk factors / S.J. Herbst

Herbst, Sara Johanna January 2005 (has links)
Motivation: Cardiovascular disease (CVD) is one of the leading causes of mortality and morbidity in South Africa and worldwide. Various investigations have confirmed the hypothesis that elevated plasma homocysteine (Hcy) levels may be linked to vascular disease, and it has become clear that hyperhomocysteinemia is an independent risk factor for atherosclerosis and atherothrombosis. Extensive research on the influence of vitamin supplementation leading to the lowering of homocysteine levels has been done, but extensive research on the effect of physical activity on high homocysteine levels is lacking. The interaction of vitamin supplementation in combination with physical activity has also not been investigated. If a conditioning exercise programme can demonstrate a lowering effect on elevated homocysteine levels, it will confirm the importance of physical activity as a less expensive alternative for a better lifestyle that can also continue to lower morbidity and mortality rates. Objective: This study examined the effect of a conditioning program, vitamin supplement and a combination of both on Hcy levels in men with coronary heart disease risk factors. Methods: In a randomized, placebo-controlled, blinded crossover study, 84 men matched for physical activity (PA) levels, age and risk factors were randomly assigned to one of 4 groups [A = physical conditioning, 20-30 min; 70-80% (THR), 8 = physical conditioning + supplement, C = supplement (12,5 ug vitamin 812; 200 ug folic acid) or D = control). Groups A, B, and C were crossed over according to the Latin square design. Total plasma homocysteine, maximal oxygen consumption (V02max) and body composition (BMI & Fat %) were measured before and after each 12-week intervention period. A 6-week washout period separated the crossovers. Results: The experimental and control groups presented similar baseline characteristics and the profile analysis of the V02max values and Hcy concentrations indicated positive results (multivariate p-value <0.0001), due to the fact that the four groups repeated measurements, presented different patterns. A phase effect for the V02max values and a phase and interaction effect for the Hcy concentrations were indicated, though all the subjects were requested to maintain their normal daily routine (eating pattern, PA levels and alcohol consumption) for the duration of the study. The lack of compliance to the conditioning programme makes it impossible to draw conclusions for V02max values. The poor compliance lead to a small sample size that eventually leads to less statistical power. Conclusion: This study found that a 12-week conditioning programme had no effect on Hcy concentrations. The results of this study make it impossible, due to poor compliance, to suggest that the effect of increased PA on homocysteine may play an important role in the prevention and treatment of CVD. It is, therefore, recommended that more studies should be conducted to further investigate the effect of PA and vitamin supplements on tHcy levels. / Thesis (M.Sc. (Human Movement Science))--North-West University, Potchefstroom Campus, 2006.
92

Selective Indicators for Optical Determination of Disease Biomarkers

Hakuna, Lovemore 01 December 2014 (has links)
The most abundant biological thiols, homocysteine (Hcy), cysteine (Cys) and glutathione (GSH) have been the subject of intense research due to their association with a wide range of diseases. They play a key role in maintaining the redox status of biological systems. Selective detection methods for these thiols are challenging due to their similar structures and properties. Current commercially available detection methods use separations, fragile and expensive enzymatic or immunogenic materials and complex instrumentation. This has led to a global effort towards developing simple and inexpensive optical probes and indicators selective for specific biological thiols. Highly selective chemical probes and simple methods for detection and potential quantification of Hcy and GSH in their natural biological media have been developed. These indicators and methods are relatively simple and inexpensive for potential application at point of care. The selective detection of Hcy using novel asymmetric viologen chemical probes at room temperature is described as well as the use of commercially available materials under photochemical conditions. These probes respond linearly proportional to increasing Hcy concentrations, potentially enabling the monitoring of Hcy levels in human plasma. Additionally, new methods for the selective determination of GSH in human plasma, as well as its quantification in whole blood deposited on filter paper (dried blood spots), is also presented herein.
93

Homocisteína, vitaminas do complexo B e perfil de ácidos graxos em crianças e adolescentes / Homocysteine, B vitamins and fatty acid profile in children and adolescents

Ued, Fábio da Veiga 03 April 2019 (has links)
Introdução: Fatores de risco para doenças cardiovasculares (DCV) tornaram-se prevalentes em crianças e adolescentes. Ácidos graxos (AGs) ?3 auxiliam na prevenção de DCV, porém seu consumo alimentar na infância é reduzido. Há a hipótese de que as vitaminas B2, B6, B12 e folato possam contribuir para o aumento da concentração de ácidos graxos poli-insaturados (PUFAs) no plasma e nos eritrócitos, além de reduzir os níveis de homocisteína total (tHcy), e auxiliar na prevenção de DCV. Por essa razão, o presente estudo teve como objetivo verificar a associação entre perfil lipídico, perfil de ácidos graxos, homocisteína e biomarcadores para vitaminas do complexo B em crianças e adolescentes. Métodos: Este estudo transversal incluiu 249 crianças e adolescentes entre 9 e 13 anos de idade. O consumo alimentar foi avaliado por meio do questionário de frequência alimentar, recordatório de 24 horas e índice de qualidade da dieta (IQD). O perfil lipídico e os biomarcadores para vitaminas B2, B6, B12 e ácido fólico foram dosados no plasma. O perfil de AGs e os metabólitos do ciclo da homocisteína (metionina, SAM, SAH, tHcy, cistationina e cisteína) foram dosados nas células vermelhas do sangue. As associações foram testadas com modelos de regressão linear múltiplos, ajustados para sexo, estadiamento puberal, índice de massa corporal e IQD. Resultados: Não houve associação entre as vitaminas do complexo B e baixos níveis de colesterol total, triglicérides e LDL-c. Porém, houve associação positiva entre os níveis séricos de vitamina B2 e folato plasmático com PUFAs ?3 e ?6. O aumento de 1 nmol/L de vitamina B2 esteve associado ao aumento de 0,19 mg/dL de EPA e 0,21 mg/dL de ARA e DHA (p<0,01). O aumento de 1 ng/mL de folato plasmático esteve associado ao aumento de 0,14 mg/dL de EPA (p<0,05), 0,22 mg/dL de ARA e 0,17 mg/dL de DHA (p<0,01). Estas vitaminas não estiveram associadas à redução dos níveis de tHcy (p>0,05). As vitaminas B6 e B12 estiveram associadas à redução dos níveis de tHcy (p<0,01), mas não se associaram a maiores níveis de PUFAs (p>0,05). Houve associação negativa entre os níveis séricos de vitamina B6 com PUFAs ?3 e ?6. O aumento de 1 nmol/L de vitamina B6 esteve associado à redução de 0,15 mg/dL de ARA e 0,14 mg/dL de DHA (p<0,05). Os níveis de tHcy foram associados positivamente com os níveis de PUFAs (p<0,01). Conclusão: Maiores concentrações plasmáticas de vitamina B2 e folato estão associadas a maiores níveis deResumo PUFAs ?3 e ?6 nos eritrócitos. A via metabólica mais provável para explicar tais associações é o metabolismo de um-carbono, apesar destas vitaminas não terem se associado a menores níveis de tHcy. Estes dados sugerem que níveis plasmáticos adequados de vitamina B2 e folato podem melhorar o perfil de AGs circulantes. O equilíbrio nas concentrações séricas de AGs ?3 e ?6 contribui para o desenvolvimento do sistema nervoso central na infância e para a prevenção de DCV, cada vez mais comuns em decorrência do sedentarismo, má alimentação e excesso de gordura corporal, em crianças e adolescentes. / Introduction: Risk factors for cardiovascular disease (CVD) have become prevalent in children and adolescents. Fatty acids (FA) ?3 help prevent CVD, but the intake of food sources of this FA during childhood is reduced. It is hypothesized that vitamins B2, B6, B12 and folate may contribute to the increased concentration of polyunsaturated fatty acids (PUFAs) in plasma and in erythrocytes, in addition to reducing total homocysteine levels (tHcy), and assisting in the prevention of CVD. For this reason, the present study aimed to verify the association between lipid profile, fatty acid profile, homocysteine and B-vitamins biomarkers in children and adolescents. Methods: This cross-sectional study included 249 children and adolescents, aged 9 to 13 years old. Dietary intake was assessed by the food frequency questionnaire, 24-hour recall, and healthy eating index (HEI). The lipid profile and biomarkers for vitamins B2, B6, B12 and folate were measured in plasma. The FA profile and metabolites from homocysteine cycle (methionine, SAM, SAH, tHcy, cystathionine and cysteine) were measured in red blood cells. The associations were tested with multiple linear regression models, adjusted for sex, pubertal status, body mass index and HEI. Results: There was no association between B vitamins and low levels of total cholesterol, triglycerides and LDL-c. However, there was a positive association between serum levels of vitamin B2 and plasma folate with PUFAs ?3 and ?6. An increase of 1 nmol/L in vitamin B2 was associated with an increase of 0.19 mg/dL of EPA and 0.21 mg/dL of ARA and DHA (p<0.01). An increase of 1 ng/mL in plasma folate was associated with an increase of 0.14 mg/dL of EPA (p<0.05), 0.22 mg/dL of ARA and 0.17 mg/dL of DHA (p<0.01). These vitamins were not associated with reduced tHcy levels (p>0.05). Vitamins B6 and B12 were associated with reduced tHcy levels (p <0.01), but were not associated with higher levels of PUFAs (p> 0.05). There was a negative association between serum levels of vitamin B6 with PUFAs ?3 and ?6. The increase of 1 nmol/L in vitamin B6 was associated with a reduction of 0.15 mg/dL of ARA and 0.14 mg/dL of DHA (p <0.05). Homocysteine levels were positively associated with PUFA levels (p <0.01). Conclusion: Higher plasma concentrations of vitamin B2 and folate are associated with higher levels of PUFAs ?3 and ?6 in erythrocytes. The most likely metabolic pathway to explain such associations is the one-carbon metabolism, although these vitamins have not been associated with lower tHcy levels. These data suggest that adequate plasma levels of vitamin B2 and folate may improve the profile of circulating FA. TheAbstract balance in the serum concentrations of FA ?3 and ?6 contributes to the development of the central nervous system in childhood and to the prevention of CVD, increasingly common due to sedentary lifestyle, poor diet and excess body fat, in children and adolescents.
94

Folato, vitamina B6 e B12: Ingestão dietética, níveis sanguíneos e relação com a concentração sérica de homocisteína em adolescentes de Indaiatuba, SP / Folate, vitamin B6 and B12: the relationship between serum homocysteine concentration and dietary intake and status of vitamins among adolescents of Indaiatuba, São Paulo.

Steluti, Josiane 24 August 2010 (has links)
Introdução: O folato e outras vitaminas do complexo B estão metabolicamente relacionadas à elevação sanguínea do aminoácido homocisteína (hcy). Este, por sua vez, se mostrou associada ao aumento de risco de eventos adversos, sobretudo as doenças cardiovasculares. Objetivo: Investigar a ingestão dietética e níveis sanguíneos das vitaminas folato, B6, e B12, e sua relação com a concentração sérica de hcy, entre adolescentes Métodos: Estudo observacional, transversal, em adolescentes de ambos os sexos, faixa etária de 16 a 19 anos, foi conduzido na escola de ensino técnico da cidade de Indaiatuba-SP-Brasil. Coletou-se registro alimentar de três dias não consecutivos. Os valores dos nutrientes referentes aos registros foram obtidos no software NDSR. Para a estimativa da dieta habitual pela remoção da variabilidade intrapessoal e a prevalência de inadequação da ingestão pelo método da EAR como ponto de corte, utilizou-se o PC-Side, versão 1.0. As análises bioquímicas de folato, B6, B12 e hcy foram conduzidas de acordo com os métodos aceitos na literatura científica. Todas as análises estatísticas foram realizadas no STATA® versão 10.0 considerando o nível de significância 5%. Resultados: O estudo foi conduzido com 99 adolescentes, sendo 58,6% do sexo feminino e média de idade de 17,6 (dp 0,9) anos. As médias da concentração sérica de folato, B6 e B12 foram de 9,2 (dp 3,4) ng/ml, 18,7 (dp 5,1) nmol/L e 397,5 (dp 188,4) pg/ml, respectivamente. 15,2% dos adolescentes apresentavam inadequação da ingestão de folato, 10,2%, de B6 e <1%, de B12. Os alimentos que mais contribuíram para a ingestão dos nutrientes foram: pão francês (23,1%), macarrão (9,7%) e feijões (8,2%) para folato; arroz branco (9,9%), carne de frango (5,7%) e carne bovina (4,2%) para B6, e carne bovina magra (16,4%), leite integral (15%) e carne bovina gorda (12,3%) para B12. Em relação à hcy, as médias foram de 15,4 (dp 10,2) µmol/L nos meninos e 8,2 (dp 2,2) µmol/L nas meninas. Dos meninos, 25% apresentavam valores séricos de hcy superiores a 15 µmol/L e diminuição da média sérica de folato e B12 quanto maior o tercil do nível sérico hcy (p<0,005). Conclusão: As prevalências de inadequação da ingestão folato, B6 e B12 mostraram-se baixas, possivelmente em decorrência da melhoria do acesso e disponibilidade de alimentos, inclusive dos alimentos processados que contêm entre os ingredientes as farinhas fortificadas com ácido fólico. No entanto, os feijões, ainda se destacaram como um dos alimentos que contribuíram para a ingestão desse nutriente. Além disso, os adolescentes do sexo masculino têm altos níveis séricos de hcy e apresentaram uma tendência de queda das médias da concentração sérica de folato e B12 quanto maior o tercil de hcy. / Introduction: Folate and the metabolically related B vitamins are intimately connected with metabolic pathways of homocysteine (hcy). Epidemiologic studies have shown that increased total homocysteine concentration is an independent predictor for a number of human diseases, especially, cardiovascular diseases. Objective: to investigate the dietary intake and status of folate, related B-vitamin, and the relationship to total homocysteine concentration among adolescents. Methods: A cross-sectional study was conducted among adolescents, both genders, aged 16 to 19 years, in a public school of Indaiatuba, São Paulo. Dietary intake was measured using three-day dietary record. The energy and nutrients were computed using Nutrition Data System for Research software. The usual intake and prevalence of inadequate by EAR cut-point method were estimated using PC-SIDE, version 1.0. Biochemical analyses were determined according the methods recommended by the scientific literature. All statistical analyses were performed using STATA, version 10.0. A two-tailed p value <0.05 was considered significant. Results: The study was conducted among 99 adolescents, 58 (58.6%) were girls, mean age of 17.6 (SD 0.9) years old. The means of folate, B6 and B12 vitamins status were of 9.2 (SD 3.4) ng/ml, 18.7 (SD 5.1) nmol/L and 397.5 (SD 188.4) pg/ml, respectively. The proportion of adolescents with folate, B6 and B12 intakes above the recommendation was 15.2%, 10.2%, e <1%, respectively. The foods that more contributed for folate intake were French bread (23.1%), pasta (9.7%) and beans (8.2%). For B6 intake rice (9.9%), chicken (5.7%) and meat (4.2%). For B12 intake, meat without fat (16.4%) whole milk (15%) and meat with fat (12.3%). The mean of hcy was 15.4 (SD 10.2) µmol/L in boys and 8.2 (SD 2.2) µmol/L in girls. In boys, 25% of them showed values of serum hcy concentration upper to 15 µmol/L and, means of folate and vitamin B12 decreased according of serum hcy tercil (p<0.005). Conclusions: The prevalence of inadequate intake of folate, vitamin B6 and B12 were low, possibly due to improved access and availability of food, including processed foods that contain the fortified flour with folic acid as ingredient. However, the beans, a component of the Brazilians usual dietary pattern, are founded as important contributors of folate intake. The total homocysteine levels were higher in boys when compared with girls. In boys, folate and vitamin B12 status were decreased significantly with trend among different tercile serum homocysteine concentration.
95

Consumo de frutas, legumes e verduras: relação com os níveis sanguíneos de homocisteína entre adolescentes / Intake of fruits and vegetables: relationship with blood levels of homocysteine among adolescents

Bigio, Roberta Schein 29 August 2011 (has links)
Introdução: Frutas, legumes e verduras (FLV) contêm vários nutrientes com efeitos favoráveis para a saúde humana. Dentre estes, o folato é um dos nutrientes chaves envolvido na manutenção da saúde, com um potencial papel na redução das concentrações plasmáticas de homocisteína (hcy), reconhecido marcador de doença cardiovascular. Objetivos: Investigar o consumo de FLV, segundo características sóciodemográficas, antropométricas e de estilo de vida e relacionar o consumo de FLV e de folato com os níveis sanguíneos de hcy em adolescentes. Métodos: Este estudo utilizou dados de adolescentes de ambos os sexos, faixa etária de 12 a 19 anos, obtidos no Inquérito de Saúde ISA - Capital, realizado periodicamente no Município de São Paulo. O consumo de FLV foi estimado no estudo realizado em 2003, cuja amostra foi de 812 participantes. Para avaliação das relações entre FLV, folato e hcy, foram utilizados dados coletados no segundo ISA-Capital, entre os anos de 2008-2010 com amostra de 183 adolescentes. O consumo de FLV e de equivalentes de folato dietético (DFE), bem como o consumo de folato natural e ácido fólico, foram estimados por um recordatório de 24h. A análise bioquímica das concentrações plasmáticas de hcy foi realizada pelo método de cromatografia líquida. O ponto de corte de hcy plasmática utilizado foi de <8 mol/L para indivíduos com menos de 15 anos e <12 mol/L para indivíduos entre 15 e 19 anos. A concentração média de hcy plasmática foi descrita de acordo com os tercis de consumo de FLV, segundo as características sócio-demográficas, antropométricas e de estilo de vida. Todas as análises estatísticas foram realizadas no STATA® versão 10.0 considerando o nível de significância 5 por cento . Resultados: No primeiro estudo (2003) 20 por cento dos adolescentes não consumiram FLV no dia relatado e 6,5 por cento apresentaram consumo adequado. Renda, escolaridade do chefe da família e tabagismo influenciaram este consumo. Já no segundo estudo (2008-2010), 56 por cento não consumiram FLV e somente 4,9 por cento atingiram as recomendações. A prevalência de hiperhomocisteinemia na população estudada foi de 9,2 por cento . Adolescentes de 12 a 15 anos apresentaram menores valores de hcy (6,9mol/L) em comparação com os de 16 a 19 anos (8,4mol/L). Não foram encontradas diferenças significativas nos níveis plasmáticos de hcy analisados por tercis de consumo de FLV segundo características sócio-demográficas, de estilo de vida e antropométricas. Os alimentos que mais contribuíram com o consumo de DFE foram: pães (38,4 por cento ), seguidos pelo feijão (11,7 por cento ) e massas (10,1 por cento ). Para folato natural os alimentos de maior contribuição foram: feijão (30,3 por cento ), FLV (14,9 por cento ) e pães (14,6 por cento ); e, para o ácido fólico, se destacaram pães (53,3 por cento ), massas (14,6) e biscoitos (9,8 por cento ). Conclusão: O consumo de FLV por adolescentes está muito abaixo das recomendações nas duas amostras estudadas e não influenciou as concentrações plasmáticas de hcy / Background: Fruits and vegetables (FV) contains multiple nutrients with beneficial effects for human health. Among these, folate is one of the key nutrients involved in maintaining health, with a potential role in reducing plasma concentrations of homocysteine (hcy), recognized marker of cardiovascular disease. Objectives: To investigate the FV intake, according to socio-demographic, anthropometric and lifestyle characteristics and to relate the FV and folate intake with blood levels of hcy in adolescents. Methods: This study used data from adolescents of both sexes, aged 12 to 19, enrolled in the Health Survey ISA - Capital, periodically held in São Paulo. The FV intake was estimated in the study conducted in 2003, comprising 812 participants. To assess the relationship between FV, folate and hcy, we used data collected in the ISA Capital, conducted between the years 2008-2010 with a sample of 183 adolescents. The FV intake and dietary folate equivalents (DFE), as well as natural folate and folic acid intake, were estimated by a 24-hour recall. Biochemical analysis of plasma hcy was performed by liquid chromatography. The cutoff point for plasma hcy was <8 mmol/L for individuals younger than 15 years and <12 mmol/L for individuals aged between 15 and 19 years. The average concentration of plasma hcy was described into tertiles of FV intake, according to the socio-demographic, anthropometric and lifestyle characteristics. All statistical analyzes were performed in STATA ® version 10.0 with 5 per cent of significance level. Results: In the first study (2003) 20 per cent of adolescents not consumed FV on day evaluated and only 6.5 per cent had adequate intake. Per capita household income, head of familys level and smoking habit influenced this consumption. In the second study (2008-2010), 56 per cent not consumed FV and only 4.9 per cent met the recommendations. The prevalence of hyperhomocysteinemia was 9.2 per cent . Adolescents aged 12 to 15 years had lower levels of hcy (6.9 mmol/L) compared with 16 to 19 years (8.4 mmol/L). No significant differences were found in plasma levels of hcy into tertiles of FV intake according to socio-demographic, lifestyle and anthropometric characteristics. Foods that most contributed to DFE intake were bread (38.4 per cent ), followed by beans (11.7 per cent ) and pasta (10.1 per cent ). For natural folate, the foods that most contributed were: beans (30.3 per cent ), FV (14.9 per cent ) and breads (14.6 per cent ), and for folic acid, breads (53.3 per cent ), pasta (14.6) and biscuits (9.8 per cent ). Conclusion: FV intake by adolescents is below the recommendations and not influenced plasma concentrations of hcy
96

Déterminants génétiques, nutritionnels et métaboliques de l'asthme professionnel / Genetic, nutritional and metabolic determinants of occupational asthma

Acouetey-Ardoin, Dovi Stéphanie 30 November 2012 (has links)
L'asthme professionnel (AP) est la maladie respiratoire d'origine professionnelle la plus fréquente dans les pays industrialisés. Il s'agit d'une pathologie complexe dite « multifactorielle » mettant en jeu un grand nombre de facteurs de risques génétiques, constitutionnels, comportementaux et environnementaux. Sur le plan génétique, l'asthme professionnel représente un bon modèle pour l'étude de l'asthme chez l'adulte et les mécanismes d'interactions gène-gène-environnement masquant ou modulant l'effet de la génétique restent encore à élucider. Aucune étude épidémiologique sur l'asthme professionnel n'a examiné le rôle des facteurs génétiques à un stade très précoce de l'exposition aux allergènes et aux irritants aéroportés. Nous avons donc cherché dans un premier temps à évaluer le rôle de certains polymorphismes génétiques en rapport avec l'inflammation et l'allergie, à savoir les IL4RA, IL13, TNFa, IL1A et IL5, sur le déclin de la fonction pulmonaire, l'apparition d'une obstruction ou d'une hyperréactivité bronchiques et l'évolution du monoxyde d'azote exhalé (FeNO) chez 441 apprentis boulangers/pâtissiers et coiffeurs (étude MIBAP). Dans cette première partie nous observons des interactions entre IL13 R130Q/IL4RA S478P et IL13 R130Q//IL4RA Q551R et la diminution du volume expiratoire forcé ou de la capacité vitale forcée. Le génotype GG du TNFA-G308A a été trouvé associé à l'hyperréactivité bronchique dans l'ensemble de la population et chez les sujets non atopiques ; nous avons aussi observé que certaines interactions gène-gène étaient associées à une modification du FeNO au cours des deux années d'apprentissage. Dans un deuxième temps, des déterminants nutritionnels de l'asthme ont été explorés dans une population de jeunes travailleurs engagés dans ces métiers à risque depuis 3 à 10 ans (étude ABCD). Les apports en vitamines, principalement les vitamines A, C, E D, et en acides gras polyinsaturés omégas 3 et 6 ont été étudiés par questionnaire de fréquence, le diagnostic d'asthme professionnel étant réalisé au moyen d'une batterie d'outils (examen clinique, spirométrie et test de réversibilité d'une obstruction bronchique, mesure du FeNO et examen des taux sériques d'IgE spécifiques). Les résultats portant sur 31 cas d'asthme professionnel et 196 témoins montrent une différence en fonction de la filière : chez les boulangers-pâtissiers, aucun facteur nutritionnel n'est objectivé, contrairement au groupe des coiffeuses chez qui les asthmatiques présentent des apports plus élevés des vitamines A et D. Un déficit en B12 semble être un facteur de risque de survenue d'asthme professionnel et ce indépendamment de la filière. En revanche, aucune corrélation n'est trouvée avec les taux sériques de l'homocystéine et la vitamine B9. A travers ces études au sein de ces jeunes populations à risque, il ressort que l'expression de certains facteurs de risque de l'asthme professionnel sont modulables en fonction du type d'exposition. Des comportements alimentaires à l'environnement de travail, l'émergence d'une maladie telle que l'asthme professionnel fait appel à des facteurs multiples dont la plupart peuvent être contrôlés et limités par des mesures de prévention efficaces / Occupational asthma (OA) is the occupational respiratory disease most common in industrialized countries. It is a multifactorial disease involving a large number of risk factors genetic, constitutional, behavioral and environmental. At the genetic level, occupational asthma is a good model for the study of adult asthma and the mechanisms of interaction gene-gene-environment masking or modulating effect of genetic remain to be elucidated. None epidemiological studies on occupational asthma have examined the role of genetic factors in a very early exposure to allergens and airborne irritants. We initially assess the role of genetic polymorphisms related to inflammation and allergy, namely IL4RA, IL13, TNF, IL1A and IL5, on the decline of lung function, bronchial hyperresponsiveness and increasing of exhaled nitric oxide (FeNO) in 441 apprentice bakers / pastry-makers and hairdressers (MIBAP study). In this first part we observed interactions between IL13 and IL13 R130Q R130Q/IL4RA S478P / / IL4RA Q551R and decreased forced expiratory volume or forced vital capacity. The GG genotype of TNFA-G308A was found associated with bronchial hyperreactivity in the general population and in non-atopic subjects, we also observed that some gene-gene interactions were associated with a change in the FeNO after two years of training. In a second time, nutritionals determinants of asthma were investigated in a population of young workers employed in these occupations at risk from 3 to 10 years (ABCD study). Intake of vitamins, especially vitamins A, C, E,D, and polyunsaturated fatty acids omega 3 and 6 were studied by frequency questionnaire, the diagnosis of occupational asthma is achieved through a battery of tools (review clinical spirometry and reversibility of bronchial obstruction, FeNO measurement and examination of serum specific IgE). The results on 31 cases of occupational asthma and 196 controls showed a difference in terms of the sector: among bakers, no nutritional factor is objectified, unlike the hairdresser's asthmatics that have higher intakes vitamins A and D. B12 deficiency appears to be a risk factor for onset of occupational asthma regardless of the sector. In contrast, no correlation was found with serum levels of homocysteine and vitamin B9. Through studies in these young people at risk, it appears that the expression of certain risk factors of occupational asthma is flexible, depending on the type of exposure. The emergence of a disease such as occupational asthma involves multiple factors, most of which can be controlled and limited by effective preventive measures
97

Associação entre polimorfismos em genes relacionados ao metabolismo de folato (RFC1, GCP2, MTHFR e MTHFD1) e alterações nas concentrações de folato, cobalamina e homocisteína em mulheres com história de abortos espontâneos recorrentes / Association between polymorphisms in genes related to folate metabolism (RFC1, GCP2, MTHFR and MTHFD1) and changes in the concentrations of folate, cobalamin and homocysteine in women with a history of recurrent miscarriages

Giusti, Kelma Cordeiro da Silva 16 October 2012 (has links)
O aborto espontâneo recorrente (AER) é caracterizado pela ocorrência de três ou mais abortos consecutivos e acomete 2-4% das mulheres em idade fértil. A etiologia está associada a vários fatores de risco, tais como anomalias uterinas, aberrações cromossômicas, autoimunidade, trombofilias, elevação na concentração de homocisteína (tHcy), porém cerca de 40% dos casos permanece sem causa definida. O metabolismo de unidades de carbono desempenha papel fundamental na disponibilidade de folato na célula, sendo essencial para o desenvolvimento placentário e fetal. Deficiência de vitaminas que regulam este metabolismo, como o ácido fólico, e polimorfismos em genes que codificam enzimas relacionadas ao metabolismo de folato (MTHFR, RFC1, GCP2 e MTHFD1) podem levar à redução das concentrações desta vitamina e ao aumento das concentrações de tHcy. Objetivo foi avaliar a associação entre polimorfismos em genes relacionados ao metabolismo do folato (RFC1, GCP2, MTHFR e MTHFD1) e o risco de se ter AER, bem como avaliar a associação entre estes polimorfismos e as alterações nas concetranções de folato, cobalamina e homocisteína. Foram constituídos três grupos: AER primário: 117 mulheres com AER e nenhum feto viável; AER secundário: 139 mulheres com AER e pelo menos um feto viável; e Controle: 264 mulheres sem história de aborto espontâneo. Nenhuma das mulheres estava grávida no momento da coleta do sangue. Amostras de sangue foram obtidas para dosagens bioquímicas (folato, Cbl, tHcy, entre outras), imunológicas e extração de DNA genômico. As genotipagens foram feitas por PCR-RFLP ou PCR em tempo real. As concentrações séricas de folato e Cbl foram maiores no AER primário e secundário (p<0,05). A distribuição dos genótipos de todos os polimorfismos foi semelhante nos três grupos. O aumento nas concentrações de folato sérico (OR: 1,05, 95% IC: 1,03 - 1,07, p<0,001), Cbl (OR: 1,00, 95% IC: 1,00 - 1,00, p= 0,016), tHcy (OR: 1,03, 95% IC: 0,97 - 1,11, p= 0,033) e T4 (OR: 1,02, 95% IC: 1,00 - 1,03, p= 0,006) e a presença de FAN reagente (1:160) (OR: 2,90, 95% IC: 1,25 - 6,75, p= 0,013) foram considerados fatores de risco para aborto primário. Para o aborto secundário, foram considerados fatores de risco o aumento nas concentrações de folato sérico (OR: 1,04, 95% IC: 1,02 - 1,05, p<0,001), Cbl (OR: 1,00, 95% IC: 1,00 - 1,00, p= 0,019) e tHcy (OR: 1,05, 95% IC: 1,00 - 1,09, p= 0,039), maiores idades (OR: 1,02, 95% IC: 0,98 - 1,06, p= 0,031), hábito de fumar (OR: 2,54, 95% IC: 1,41 - 4,60, p= 0,002) e ter maior IMC (OR:1,42, 95% IC: 1,07 - 1,88, p= 0,015). Os polimorfismos estudados não foram associados ao maior risco de se ter AER, quando analisados isoladamente, e também não foram associados a alterações nas concentrações séricas de folato, Cbl e tHcy, com exceção do genótipo MTHFR 677TT, cujas portadoras apresentaram maior concentração de tHcy, quando comparadas com as portadoras de genótipos 677CC e 677CT nos três grupos. As variáveis concentrações de folato, Cbl, tHcy e T4 e presença de FAN reagente foram associadas ao maior risco de se ter aborto primário. As variáveis idade, IMC, tabagismo, concentrações de folato, Cbl e tHcy foram associadas ao maior risco de aborto secundário. / The recurrent spontaneous abortion (RSA) is characterized by the occurrence of three or more consecutive miscarriages and affects 2-4% of women of childbearing age. The etiology is associated with several risk factors such as uterine abnormalities, chromosomal aberrations, autoimmunity, thrombophilia, increased concentration of homocysteine (tHcy). About 40% of cases remains unknown cause. The units of carbon metabolism plays an essential role in the availability of the cell folate, is essential for the placental and fetal development. A deficiency of the vitamins that regulate this metabolism, like folic acid, and polymorphisms in genes encoding enzymes related to folate metabolism (MTHFR, RFC1, and GCP2 MTHFD1) may lead to decreased concentrations of this vitamin and increased concentrations of tHcy. Objective was to evaluate the association between polymorphisms in genes related to folate metabolism (RFC1, GCP2, MTHFD1 and MTHFR) and the risk of having AER, and to evaluate the association between these polymorphisms and changes in concetranções folate, cobalamin, and homocysteine. Three groups were divided: AER primary: 117 women with RSA and no viable fetus, AER secondary: 139 women with RSA and at least one viable fetus and Control: 264 women with no history of miscarriage. None of the women was pregnant at time of blood collection. Blood samples were taken for biochemical (folate, Cbl, tHcy, etc.), immunological and genomic DNA extraction. The genotyping were carried out by PCR-RFLP or real time PCR. Serum concentrations of folate and Cbl were higher in groups 1 and 2 (p <0.05). The distribution of genotypes of MTHFR c.677C> T, MTHFR c.1298A> C, MTHFD1 c.1958G> A, RFC1 c.80G>GCP2 A and c.1561C> T was similar among the three groups. The increased concentrations of serum folate (OR: 1.05, 95% CI: 1.03 - 1.07, p <0.001), Cbl (OR: 1.00, 95% CI: 1.00 to 1.00, p = 0.016), tHcy (OR: 1.03, 95% CI: 0.97 to 1.11, p = 0.033) and T4 (OR: 1.02, 95% CI: 1.00 to 1.03, p = 0.006) and the presence of ANA (1:160) (OR: 2.90, 95% CI: 1.25 - 6.75, p = 0.013) were considered risk factors primary for abortion. For secondary abortion, were considered risk factors increased the concentrations of serum folate (OR: 1.04, 95% CI: 1.02 - 1.05, p <0.001), cobalamin (OR: 1.00, 95 % CI: 1.00 to 1.00, p = 0.019) and tHcy (OR: 1.05, 95% CI: 1.00 to 1.09, p = 0.039), higher age (OR: 1.02, 95% CI: 0.98 to 1.06, p = 0.031), cigarette smoking (OR: 2.54, 95% CI: 1.41 to 4.60, p = 0.002) and had a higher BMI (OR : 1,42,95% CI: 1.07 to 1.88, p = 0.015). The studied polymorphisms were not associated with increased risk of having RSA when analyzed separately, and were not associated with changes in serum folate, Cbl and tHcy, with the exception of the MTHFR 677TT genotype, whose patients had a higher concentration of total tHcy compared with those with 677CC and 677CT genotypes in the three groups. The variable concentrations of folate, Cbl, tHcy, and T4, presence of ANA and have been associated with increased risk for miscarriage primary. The variables age, BMI, smoking, concentrations of folate, Cbl and tHcy were associated with increased risk of secondary miscarriage.
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Consumo de cobalamina e folato por gestantes: relação com o metabolismo da homocisteína e com os polimorfismos nos genes da metionina sintase, metilenotetraidrofolato redutase e metionina sintase redutase / Cobalamin and folate intake by pregnant women: its relationship to homocysteine metabolism and to polymorphism in methionine synthase, methylenetetrahydrofolate reductase and methionine synthase reductase genes

Pereira, Perla Menezes 15 February 2007 (has links)
Os consumos inadequados de cobalamina (Cbl) e de folato associados aos polimorfismos em genes de enzimas chaves do metabolismo da homocisteína podem agravar as comorbidades relacionadas a deficiências destas vitaminas. Os objetivos deste estudo foram avaliar o consumo de cobalamina, de folato e de vitamina 86 por gestantes através de três inquéritos recordatórios de 24 horas (IR24h); determinar as correlações entre as concentrações séricas de folato, de cobalamina, de metionina, de .S-adenosilmetionina (SAM), de Sadenosilhomocisteína (SAH), de homocisteína total (tHcy) e de ácido metilmalônico (MMA) com as vitaminas e as proteínas ingeridas na dieta pelas mulheres; analisar as associações entre os polimorfismos MTHFR C677T, MTHFR A1298C, MTR A2756G e MTRR A66G e alterações nas concentrações das vitaminas e dos metabólitos, além de avaliar os determinantes nutricionais e genéticos das concentrações dos metabólitos tHcy\" SAM, MMA e SAM/SAH durante a gestação. Participaram do estudo 73 mulheres com idades gestacionais de 16, 28 e 36 semanas, no qual foram aplicados três IR24h para cada gestante, um em cada idade gestacional. Foram realizadas as dosagens séricas de cobalamina sérica, folato sérico e eritrocitário, homocisteína total, metionina, MMA, SAM e SAH. As genotipagens dos polimorfismos MTHFR C677T, MTHFR A1298C, MTR A2756G e MTRR A66G foram feitas por PCR-RFLP. Observou-se que a ingestão de folato foi baixa em relação ao valor de 600 &#181;g/dia recomendado para gestantes, a ingestão de cobalamina foi menor que a encontrada na literatura, a ingestão de vitamina 86 e a de proteínas totais foram semelhantes às da literatura. As concentrações de Cbl séricas foram diretamente relacionadas com a ingestão de proteínas. As concentrações de MMA estavam relacionadas inversamente com a ingestão de cobalamina, com a ingestão das proteínas totais e com a renda per capita. Houve redução das concentrações de cobalamina sérica e aumento de MMA no decorrer das idades gestacionais, sendo observada maior concentração sérica de MMA entre as mulheres que ingeriram menos cobalamina. Não houve associação entre os polimorfismos MTHFR A1298C e MTRR A66G e as variações nas concentrações de vitaminas e de metabólitos. Com relação ao polimorfismo MTHFR C677T, as mulheres portadoras do alelo 677T possuíam menores concentrações médias de foiato eritrocitário, e para o polimorfismo MTR A2756G, as mulheres com genótipos AG e GG apresentaram menores concentrações de metionina. As concentrações aumentadas de tHcy foram explicadas pelas menores concentrações de folato eritrocitário, pela menor ingestão de proteínas totais, pelas maiores concentrações de creatinina sérica e pela ingestão de vitamina 86. A creatinina sérica foi a responsável pela variabilidade das concentrações da SAM. Maiores concentrações de folato sérico e menores concentrações de creatinina sérica foram os responsáveis pelo aumento dos valores da SAM/SAH. As maiores concentrações de MMA foram atribuídas à menor ingestão de cobalamina, à menor renda per capita e à menor concentração sérica de cobalamina. Conclusões: a ingestão de folato foi menor que a metade do recomendado. A ingestão de cobalamina atingiu o recomendado, no entanto não foi suficiente para manter o metabolismo materno. Os polimorfismos não foram associados a baixa ingestão de vitaminas para explicar as alterações nas concentrações de tHcy, da SAM, da SAM/SAH e do MMA. / The inadequate intake of cobalamin and folate associated to polymorphisms in key-enzyme genes of homocysteine can worsen comorbidities related to the deficiency of these vitamins. The aims of this study were to evaluate the intake of cobalamin, foiate and vitamin 86 by pregnant women through three 24-hour dietary recaIl (IR24h); to assess the correlation between serum concentrations of folate, cobalamin, methionine, S-adenosilmethionine (SAM), S-adenosilhomocysteine (SAH), total homocysteine (tHcy) and methylmalohic acid (MMA)towards vitamins and proteins intaked by women, to analyze association between MTHFR C677T, MTHFR A1298C, MTR A2756G and MTRR A66G polymorphisms and changes on vitamin and metabolites concentration, and to determine the nutritional and genetic determinants during a gestational period. 73 pregnant women participated in this study, with gestational ages of 16,28 and 36 weeks, onto whom were applied three IR24h to each woman, being one in each gestational age. Serum concentrations of cobalamin, foiate and red blood cell foiate, total homocysteine, methionine, MMA, SAM and SAH were evaluated. The polymorphisms of MTHFR C677T, MTHFR A1298C, MTR A2756G and MTRRA66G were performed by PCR-RFLP. It was observed that folate intake was low in relationship to recommended value for pregnant women of 600 &#181;g/day. Cobalamin intake was less than the one found in literature. Vitamin 86 and total protein intake was similar to the one found in literature. Serum Cbl concentrations were directly related to protein intake. MMA concentrations were in,verselycorrelated to cobalamin intake, to total proteins intakes and mounth per capita income. There were reduction of serum cobalamin concentration and enhance of MMAthroughout pregnancy weeks, being observed higher serum concentration of MMAamongst women that intaked less cobalamin. There was no association between MTHFRA1298Cand RRA66Gpolymorphism and the change in vitamins and metabolites concentrations. The women carrying allele 2756G for MTR polymorphism presented lesser serum methionine concentrations and alieie 677T for MTHFR C677T had less concentration of red blood cell folate. The red blood cell folate concentrations, intake of total proteins, serum creatinine concentrations and intake of vitamin 86 were eterminant of tHcy concentration. Serum creatinine was responsible for SAMconcentrations variability. Higher concentrations of serum foiate and lesse r concentrations of serum creatinine were responsible for the enhance of SAM/SAHvalues. The higher concentrations of MMAwere attributed to lesse r cobalamin intake, to lower per capita income and to lesser seruro concentration Df coba}amin. ConcJusions: lo/ate intake was less than ha(f of recommended amount, and cobalamina intake reached the recommended amount, however this amount was not enough to keeping the maternal metabolism. The poly~orphisms were not associated to low vitamin intake for explaining the changes Inserum concentrationsof tHcy,SAM,SAM/SAHand MMA.
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Frequência de poliformismos relacionados ao metabolismo do folato e fatores associados às concentrações de homocisteína em mulheres de baixa renda de São Paulo / Frequency of polymorphisms related to folate metabolism and factors associated with homocysteine concentrations in low-income women in Sao Paulo

Almeida, Lana Carneiro 26 August 2010 (has links)
Introdução Hiperomocisteinemia é um fator de risco para defeitos de fechamento no tubo neural e doenças vasculares e neurodegenerativas, e possui determinantes ambientais, metabólicos e genéticos. Estudos sobre freqüência de polimorfismos relacionados ao metabolismo da homocisteína (Hcy) e sua relação com dieta, fatores do estilo de vida e concentração plasmática de Hcy na população brasileira são ainda escassos. Objetivo Investigar a frequência de polimorfismos das enzimas metilenotetraidrofolato redutase (MTHFR C677T [rs1801133] e A1298C [rs1801131]), metionina sintase (MTR A2756G [rs1805087]), metionina sintase redutase (MTRR A66G [rs1801394]) e do carreador de folato reduzido (RFC G80A [rs1051266]) e sua associação com fatores dietéticos, estilo de vida e concentrações séricas ou plasmáticas de Hcy e vitaminas B12, B6 e folato em mulheres de São Paulo. População e métodos Análise transversal de dados de 609 mulheres (21-65 anos) participantes do estudo caso-controle de base hospitalar The Brazilian Investigation into Nutrition and Cervical Cancer Prevention (BRINCA) Study, excluindo-se os casos de câncer. A ingestão alimentar habitual foi avaliada por questionário de freqüência alimentar. Amostras sangüíneas em jejum foram obtidas sob proteção da luz, com separação imediata do plasma e armazenamento a -70ºC. Concentrações séricas de ácido fólico e vitamina B12 foram analisadas por técnica de fluoroimunoensaio, enquanto concentrações plasmáticas de Hcy e vitamina B6 foram analisadas por cromatografia líquida de alta performance em fase reversa. A detecção dos polimorfismos foi realizada por técnica de reação de cadeia de polimerase. As análises estatísticas foram realizadas através do programa STATA versão 10.0, ao nível de significância p<0,05. Resultados Genótipo homozigoto polimórfico foi observado em 6,6 por cento (MTHFR 677TT), 4,4 por cento (MTHFR 1298CC), 4,5 por cento (MTR 2756GG), 17,1 por cento (MTRR 66GG) e 24,4 por cento (RFC 80AA) das mulheres analisadas. Genótipo MTHFR 677TT associou-se a maiores concentrações plasmáticas de Hcy e menores concentrações séricas de folato e vitamina B12, quando comparadas aos genótipos 677CT e 677CC (p<0,005). Em contraste, mulheres portadoras de homozigose selvagem para os polimorfismos MTHFR A1298C, MTR A2756G e MTRR A66G apresentaram maiores concentrações plasmáticas de Hcy quando comparadas às mulheres portadoras de heterozigose e/ou homozigose polimórfica (p<0,005). O efeito de maior consumo de vitamina B6 na concentração de Hcy foi mais pronunciado entre fumantes que entre não-fumantes (p da interação=0,025). Entre fumantes, valores médios de Hcy em mulheres 677TT foram 64,8 por cento e 51,8 por cento maiores quando comparadas às 677CT e 677CC, respectivamente; portadoras do genótipo 1298CC apresentaram maiores concentrações plasmáticas de Hcy em relação àquelas com genótipo 1298AA e 1298AC; entre não-fumantes, entretanto, mulheres 1298AC apresentaram menores concentrações plasmáticas de Hcy do que as mulheres 1298AA. Fumantes que reportaram ingestão de café >173 g/dia tiveram concentrações plasmáticas de Hcy 1,3 mol/L (12,7 por cento) mais altas do que as não-fumantes com consumo de café 173 g/dia (p da interação=0,042). Mulheres sem ingestão alcoólica habitual e que reportaram ser fumantes apresentaram concentrações medianas de Hcy 3,4 mol/L (35 por cento) mais elevadas do que mulheres com consumo de álcool >21,4 g/dia, mas não-fumantes (p da interação=0,008). Conclusão Nesta população de mulheres com baixa prevalência de deficiência de folato sérico (5,1 por cento), fatores do estilo de vida, sobretudo tabagismo e ingestão habitual de álcool, modificam a relação entre consumo alimentar, polimorfismos e concentrações de Hcy, reforçando as recomendações para não fumar e de consumo de álcool com moderação / Introduction Hyperomocysteinemia is a risk factor for neural tube defect and vascular and neurodegenerative diseases, and has genetic, metabolic and environmental determinants. Studies evaluating frequency of polymorphisms related to homocysteine (Hcy) metabolism and its relation with diet, lifestyle factors and plasma Hcy concentration in Brazilian population are scarce. Objectives To assess the frequency of methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C, methionine synthase (MTR) A2756G, methionine synthase reductase (MTRR) A66G and reduced folate carrier (RFC) A80G gene polymorphisms, and examine its association with dietary factors, lifestyle and serum or plasma Hcy and vitamins B12, B6 and folate among low-income Brazilian women. Subjects and methods This cross-sectional study included 609 women (21-65 years) participating in The Brazilian Investigation into Nutrition and Cervical Cancer Prevention Study (BRINCA Study), excluding cancer cases. The dietary intakes regarding the previous year were estimated using a validated food frequency questionnaire. Fasting blood samples were taken from each study participant, protected from light, immediately separated plasma or serum and storaged at -70oC. Serum folate and vitamin B12 concentrations were measured by fluoroimmunoassay, and plasma vitamin B6 and Hcy concentrations were assessed by reverse-phase high performance liquid chromatography. Gene polymorphisms were ascertained using the protein chain reaction-based method. Statistical analyses were performed using STATA 10.0, using a statistical significance level of p<0,05. Results Frequencies for the homozygous variant genotypes were: 6.6 per cent (MTHFR 677TT), 4.4 per cent (MTHFR 1298CC), 4.5 per cent (MTR 2756GG), 17.1 per cent (MTRR 66GG) and 24.4 per cent (RFC 80AA) of the analysed women. MTHFR 677TT genotype has been associated to higher plasma Hcy concentration and lower serum folate and vitamin B12 concentration, compared to 677CT and 677CC genotypes (p<0,005). On the contrary, women carrying MTHFR A1298C, MTR A2756G and MTRR A66G wild homozygous have presented higher plasma Hcy concentrations when compared to those heterozygous and/or polymorphic homozygous (p<0,005). The effect of a higher vitamin B6 consumption on plasma Hcy concentration was more pronounciated among smokers than non-smokers (interaction p=0.025). Among smokers, mean Hcy values among 677TT subjects were 64.8 per cent and 51.8 per cent higher than 677CT and 677CC, respectively; 1298CC subjects presented higher plasma Hcy concentrations than 1298AA and 1298AC; among non-smokers, however, 1298AC subjects showed lower plasma Hcy concentrations than 1298AA subjects. Smokers who reported coffee intake >173g/d had plasma Hcy concentrations 1.3 mol/L (12.7 per cent) higher than non-smokers consuming coffee 173g/d (interaction p=0.042). Non-drinkers women who reported be smokers showed median plasma Hcy concentrations 3.4 mol/L (35 per cent) higher than those with alcohol consumption >21.4g/d, but non-smokers (interaction p=0.008). Conclusion In this women sample with low prevalence of serum folate deficiency (5.1 per cent), lifestyle factors, especially smoking and alcohol consumption, modifie the relation among food intake, polymorphisms and plasma Hcy concentration, reforcing the health recommendations to stop smoking and moderate alcohol consumption
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Associação entre os polimorfismos nos genes da Transcobalamina II (TCN2 c.776C&gt;G e TC2 c. 67A&gt;G) e da metilenotetraidrofolato redutase (MTHFR c.677C&gt;T) e o risco de ter abortos espontâneos recorrentes / Association between polymorphisms in the transcobalamin II (TCN2 c.776C> G and c TC2. 67A> G) and methylenetetrahydrofolate reductase (MTHFR c.677C> T) and the risk of having recurrent miscarriages.

Lazaro, Robson José 19 August 2013 (has links)
O aborto espontâneo recorrente (AER) é definido pela ocorrência de três ou mais abortos espontâneos consecutivos com idade gestacional de até 20 semanas. O AER é um evento multifatorial, tem um índice de elucidação da causa na ordem de 50% e, mesmo com os avanços da medicina diagnóstica ainda assim 40% dos casos permanecem com sua causa desconhecida. O crescimento fetal é totalmente dependente do aporte de nutrientes oirundos da mãe, dentre esses nutrientes a cobalamina e o ácido fólico desempenham um papel fundamental para a viabilidade fetal. O objetivo geral deste estudo foi investigar se existe associação entre polimorfismos em genes relacionados ao metabolismo da cobalamina (MTHFR c.677C>T, TCN2 c. 776C>G e TCN2 c. 67A>G), e o aborto espontâneo recorrente. Os objetivos específicos deste estudo foram: 1 determinar se os polimorfismos MTHFR c. 677C>T, TCN2 c. 776C>G e TCN2 c. 67A>G estão associados ao aborto primário e secundário. 2 - Avaliar se os genótipos dos polimorfismos estudados estão relacionados com as concentrações séricas de cobalamina, folato e homocisteína total em mulheres com aborto espontâneo recorrente. Foram incluídas 256 mulheres com história de abortos espontâneos recorrentes, provenientes do Ambulatório de Obstetrícia da Clínica Obstétrica do Hospital das Clínicas da Faculdade de Medicina da USP e 264 mulheres saudáveis, sem história de aborto espontâneo e que tenham tido pelo menos duas gestações normais (grupo controle), pareadas segundo as idades. Foram colhidas amostras de sangue para a realização das dosagens bioquímicas, hormonais e das vitaminas e também para a realização das genotipagens dos polimorfismos por meio de PCR-RPFL (MTHFR c.677C>T , TCN c.776C>G e c. 67A>G). As dosagens bioquímicas e hormonais apresentaram resultados dentro dos limites de variação do normal. Quanto as concentrações de folato e cobalamina, houve diferença estatística significante entre os grupos p<0,05. As frequências dos genótipos e alelos para os polimorfismos estudados comparadas entre os grupos abortos primário, aborto secundário e grupo controle não apresentaram diferença estatística significante. Optamos a seguir por dividir o grupo de estudo entre abortos primários, onde não existe história de feto viável, e secundário neste caso onde há história de feto viável. Desta forma foram refeitas as análises estatísticas entre os grupos e encontramos diferença estatísticamente significante p<0,05 quando confrontamos os genótipos do polimorfismo TCN c.776C>G entre o grupo primário e o grupo controle. Em conclusão, quando comparamos as frequência dos genótipos e alelos em conjunto não apresentaram associação com o AER. Quando comparado separadamente o grupo de aborto primário e grupo controle houve diferença estatística significante associando o polimorfismo TCN2 c.776C>G ao AER primário. / The recurrent spontaneous abortion (RSA) is defined by the occurrence of three or more consecutive miscarriages with gestational age up to 20 weeks. The AER is a multifactorial event, has an index of elucidating the cause of around 50% and, even with advances in diagnostic medicine still remain 40% of cases with a known cause. Fetal growth is totally dependent on the supply of nutrients from the mother oirundos among these nutrients cobalamin and folic acid play a key role in fetal viability. The aim of this study was to investigate whether there is an association between polymorphisms in genes related to metabolism of cobalamin (MTHFR c.677C> T, c TCN2. 776c> G and c TCN2. 67A> G), and recurrent miscarriage. The specific objectives of this study were: 1 determine whether MTHFR c. 677C> T, TCN2 c. 776c> G and c TCN2. 67A> G are associated with abortion primary and secondary. 2 - Assess whether the genotypes studied polymorphisms are associated with serum concentrations of cobalamin, folate and total homocysteine in women with recurrent spontaneous abortion. We included 256 women with a history of recurrent miscarriages, from the Clinic of Gynecology, Obstetrics, Hospital das Clinicas, Faculty of Medicine, USP and 264 healthy women with no history of miscarriage and have had at least two normal pregnancies (group control), matched according to age. Blood samples were collected to perform the biochemical, hormonal and vitamins and also to perform the genotyping of polymorphisms by PCR-RPFL (MTHFR c.677C> T, TCN c.776C> G and c. 67A> G). The biochemical and hormonal results presented within the limits of normal variation. As the concentrations of folate and cobalamin, statistically significant difference between groups p <0.05. The frequencies of genotypes and alleles for the polymorphisms studied compared between groups abortions primary, secondary and abortion control group showed no statistically significant difference. We chose then to divide the study group between primary abortions where there is a history of viable fetus, and secondary in this case where there is a history of viable fetus. Thus were repeated statistical analyzes between groups and found statistically significant difference p <0.05 when confronted TCN genotypes of polymorphism c.776C> G between the primary group and the control group. In conclusion, when comparing the frequency of genotypes and alleles together apresntaram no association with AER. When compared separately the group of abortion primary and control group was statistically significant associated polymorphism TCN2 c.776C> G the primary AER.

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