Análise da expressão de genes em gêmeos monozigóticos: impacto da aptidão cardiorrespiratória
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Data
2010-10-02
Autores
Queiroga, Marcos Roberto [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Estudos experimentais revelam que uma baixa aptidão cardiorrespiratória (VO2máx) está associada a distúrbios moleculares e bioquímicas que influenciam a sensibilidade e a secreção de insulina. Contudo, não está bem definido se esta associação é confundida por fatores genéticos. Utilizando o modelo de controle de casos (gêmeos monozigóticos (MZ) discordantes) este estudo, de caráter transversal, avaliou 38 pares de gêmeos MZ com idade entre 11 a 18 anos, dos quais nove pares demonstraram diferença média intra-par para o VO2máx de 13,5±3,7 ml.kg-1.min-1 (30,6±9,5%). O objetivo foi investigar o impacto da discordância no VO2máx nas concentrações bioquímicas de glicose, insulina, lipídios, leptina, interleucina 6 e na expressão do mRNA dos genes SUR1, KIR6.2, IL6, LEPTINA e PPARg, independente de efeitos genéticos. Foram obtidas as medidas antropométricas de massa corporal, estatura, circunferência da cintura (CC) e espessuras de dobras cutâneas (EDC). Um teste de esforço máximo em esteira rolante com análise direta dos gases foi utilizado para a determinação do VO2máx e uma colheita de sangue em jejum e pós-carga de glicose (TOTG) para a realização de exames laboratoriais, extração dos genes e estimativa do índice HOMA-RI e HOMA-β. A expressão do mRNA dos genes foi quantificada e avaliada por RT-PCR enquanto as variáveis laboratoriais foram determinadas por kits específicos. Os resultados revelaram maior adiposidade corporal (soma de 6 EDC), índice HOMA (RI e β), concentração sanguínea de leptina, insulina em jejum e pós-carga (2 h) favorecendo as meninas, enquanto os meninos demonstraram maior VO2máx. Correlação negativa foi observada entre o VO2máx e os indicadores de obesidade (IMC, CC e adiposidade), índice HOMA (RI e β) e concentração sanguínea de leptina, insulina em jejum e pós-carga (2 h)...
Experimental studies have shown that low cardiorespiratory fitness (VO2max) is associated with molecular and biochemical disturbances that influence insulin sensitivity and secretion. However, it is not defined whether this association is confounded by genetic factors. Using the monozygotic co-twin case-control, this cross-sectional study evaluated 38 MZ twins pairs from 11 to 18 years of age, of which nine pairs presented a mean intrapair difference in VO2max of 13.5 ± 3.7 ml.kg-1.min-1 (30.6 ± 9.5%). The objective was to investigate the impact of the discordances of VO2max on biochemical concentrations of glucose, insulin, lipids, leptin, and interleukin 6, as well as in genes SUR1, Kir6.2, IL6, leptin and PPARgamma mRNA expression, independent of genetic effects. We obtained the anthropometric measures of body weight, height, waist circumference (WC) and skinfold thickness (ST). The maximal treadmill test with direct analysis of inhaled and exhaled gases was used for determination of VO2max, as well as fasting and oral glucose tolerance tests (OGTT) blood sample collections for laboratory analysis, gene extraction and estimation of HOMA-IR and HOMA-β indexes. mRNA genes expression was quantified and evaluated by RT-PCR, while laboratory variables were determined using specific kits. The results showed greater body adiposity (sum of 6 STs), HOMA (IR and β) indexes, blood leptin concentration and fasting and post load (2 h) insulin levels in girls, while boys showed greater VO2max. Negative correlation was found between VO2max and indicators of obesity (BMI, WC and fatness), HOMA (IR and β) indexes and blood leptin concentration and fasting and post load (2 h) insulin levels and positive correlation with PPARgamma gene expression. Regarding the discordant pairs, we observed that the co-twins with the highest VO2max values (45.9 ± 10.0 ml.kg-1.min-1) had significanty... (Complete abstract click electronic access below)
Experimental studies have shown that low cardiorespiratory fitness (VO2max) is associated with molecular and biochemical disturbances that influence insulin sensitivity and secretion. However, it is not defined whether this association is confounded by genetic factors. Using the monozygotic co-twin case-control, this cross-sectional study evaluated 38 MZ twins pairs from 11 to 18 years of age, of which nine pairs presented a mean intrapair difference in VO2max of 13.5 ± 3.7 ml.kg-1.min-1 (30.6 ± 9.5%). The objective was to investigate the impact of the discordances of VO2max on biochemical concentrations of glucose, insulin, lipids, leptin, and interleukin 6, as well as in genes SUR1, Kir6.2, IL6, leptin and PPARgamma mRNA expression, independent of genetic effects. We obtained the anthropometric measures of body weight, height, waist circumference (WC) and skinfold thickness (ST). The maximal treadmill test with direct analysis of inhaled and exhaled gases was used for determination of VO2max, as well as fasting and oral glucose tolerance tests (OGTT) blood sample collections for laboratory analysis, gene extraction and estimation of HOMA-IR and HOMA-β indexes. mRNA genes expression was quantified and evaluated by RT-PCR, while laboratory variables were determined using specific kits. The results showed greater body adiposity (sum of 6 STs), HOMA (IR and β) indexes, blood leptin concentration and fasting and post load (2 h) insulin levels in girls, while boys showed greater VO2max. Negative correlation was found between VO2max and indicators of obesity (BMI, WC and fatness), HOMA (IR and β) indexes and blood leptin concentration and fasting and post load (2 h) insulin levels and positive correlation with PPARgamma gene expression. Regarding the discordant pairs, we observed that the co-twins with the highest VO2max values (45.9 ± 10.0 ml.kg-1.min-1) had significanty... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Genética, Expressão gênica, Gêmeos monozigóticos, Controle de casos (discordantes), Adipocinas, Gene expression, Adipokines
Como citar
QUEIROGA, Marcos Roberto. Análise da expressão de genes em gêmeos monozigóticos: impacto da aptidão cardiorrespiratória. 2010. 88 f. Tese (doutorado) - Universidade Estadual Paulista, Instituto de Biociências de Rio Claro, 2010.