Gracia María Martín-Núñez

Biomedical Research Institute of Malaga (IBIMA), Málaga, Andalusia, Spain

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Publications (9)24.92 Total impact

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    ABSTRACT: The role of selenium exposure in preventing chronic disease is controversial, especially in selenium-repleted populations. At high concentrations, selenium exposure may increase oxidative stress. Studies evaluating the interaction of genetic variation in genes involved in oxidative stress pathways and selenium are scarce. We evaluated the cross-sectional association of plasma selenium concentrations with oxidative stress levels, measured as oxidized to reduced glutathione ratio (GSSG/GSH), malondialdehyde (MDA) and 8-oxo-7,8-dihydroguanine (8-oxo-dG) in urine, and the interacting role of genetic variation in oxidative stress candidate genes, in a representative sample of 1,445 men and women aged 18-85 years from Spain. The geometric mean of plasma selenium levels in the study sample was 84.76µg/L. In fully adjusted models the geometric mean ratio for oxidative stress biomarkers levels comparing the highest to the lowest quintiles of plasma selenium levels were 0.61 (0.50-0.76) for GSSG/GSH, 0.89 (0.79-1.00) for MDA, and 1.06 (0.96-1.18) for 8-oxo-dG. We observed non-linear dose-responses of selenium exposure and oxidative stress biomarkers, with plasma selenium concentrations above ~110μg/L being positively associated with 8-oxo-dG, but inversely associated with GSSG/GSH and MDA. In addition, we identified potential risk genotypes associated with increased levels of oxidative stress markers with high selenium levels. Our findings support that high selenium levels increase oxidative stress in some biological processes. More studies are needed to disentangle the complexity of selenium biology and the relevance of potential gene-selenium interactions in relation to health outcomes in human populations.
    Free radical biology & medicine. 07/2014;
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    ABSTRACT: The serum fatty acid (FA) composition is influenced by dietary fat and the endogenous production of FAs. Stearoyl CoA desaturase 1 (SCD1) is the rate-limiting enzyme catalyzing the synthesis of MUFAs from saturated FAs. Variations in SCD1 activity have been associated with obesity, diabetes, or inflammation. We evaluated the associations between genetic variation of the SCD1 gene, SCD1 activity, intake of oil, and obesity in a population-based prospective study in southern Spain. We collected phenotypic, metabolic, nutritional, and genetic information. The type of dietary fat was assessed from samples of cooking oil taken from the participants' kitchens and analyzed by GC. A total of nine single nucleotide polymorphisms (SNPs) of the SCD1 gene were analyzed by SNPlex technology. We found a significant association between SCD1 genetic variation and enzyme activity in four of nine polymorphisms studied. An interaction between rs10883463 and olive oil intake on the [18:1/18:0] desaturase index was found (p = 0.009). We also showed that genetic variations in the SCD1 gene were associated with obesity. Our results show a relationship between genetic variation of the SCD1 gene, enzyme activity, and the risk of obesity, an association that is not independent of the type of oil consumed.
    Molecular Nutrition & Food Research 08/2013; · 4.31 Impact Factor
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    ABSTRACT: Fat-free mass depletion has been related to increased inflammatory activity and to increased morbidity and mortality in chronic respiratory diseases. The aims of our study were to determine the nutritional status and serum levels of adipocytokines and inflammatory cytokines in patients with bronchiectasis of any etiology and their relation with respiratory parameters. A cross-sectional study was designed that included patients aged >14 years with diagnostic criteria for bronchiectasis. Anthropometric parameters; a diet questionnaire; hand grip dynamometry; levels of leptin, adiponectin, interleukin-6 (IL-6), tumor necrosis factor-α, and ultrasensitive C-reactive protein; as well as respiratory parameters (ie, clinical, radiologic, and spirometric values) were assessed. Ninety-three clinically stable patients were recruited, 43 with cystic fibrosis, 31 with noncystic fibrosis bronchiectasis, and 19 with cystic fibrosis transmembrane conductance regulator-related bronchiectasis. Fat-free mass depletion was present in 31% of patients, with no differences according to the etiology of the bronchiectasis. Correlations were found between inflammatory cytokines (ie, IL-6) and exacerbations, bronchorrea, forced expiratory volume in 1 second, and Bhalla score. Patients with worse respiratory disease severity, malnutrition, and diabetes had significantly higher levels of IL-6. Adiponectin correlated significantly and positively with fat mass and fat mass index and negatively with fat-free mass, fat-free mass index, and hand dynamometry. Leptin correlated positively with body mass index, fat mass and fat mass index, and negatively with fat-free mass, fat-free mass index, and dynamometry. Patients with bronchiectasis present a high percentage of fat-free mass depletion, independent of the etiology of the disease. The levels of inflammatory cytokines (especially IL-6) may be useful markers of disease severity. Adiponectin levels were higher in patients with fat-free mass depletion.
    Journal of the American Academy of Nutrition and Dietetics 12/2012; 112(12):1999-2006. · 3.80 Impact Factor
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    ABSTRACT: High resolution melting is a post-PCR-based method for detecting DNA sequence variation by measuring changes in the melting of a DNA duplex. Melting of double-stranded DNA molecules is influenced by several factors. We evaluated the influence of the DNA isolation method in the melting curve analysis to detect genetic variations. We isolated DNA from whole blood of 547 subjects by two different methods: Maxwell 16 Instrument and DNA FlexiGene Kit. A fragment of 159 bp was amplified and analyzed by high resolution melting. Those samples that showed a different melting curve pattern were sequenced. Of the samples extracted with the Maxwell 16 Instrument, 42% showed variation compared with 0.18% of the samples extracted with DNA FlexiGene Kit. After sequencing, we showed that all samples extracted with the Maxwell 16 Instrument were false positive except one, which coincided with the only sample that showed variation in those extracted with the DNA FlexiGene Kit. The method used to extract DNA is an important factor to consider in the analysis of melting curves obtained by high resolution melting, as it may influence the melting behaviour of the samples, giving false positive results in the detection of genetic variants.
    Clinica chimica acta; international journal of clinical chemistry 09/2011; 413(1-2):331-3. · 2.54 Impact Factor
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    ABSTRACT: Eur J Clin Invest 2012; 42 (1): 79–85AbstractAim  To evaluate the association between serum levels of testosterone, sex hormone-binding globulin (SHBG) and calculated bioavailable testosterone (bioT), and the risk of type 2 diabetes mellitus (T2D) in a prospective cohort from southern Spain (Pizarra study).Research design and methods  The study was performed in the Pizarra Cohort Study, a prospective study started in 1995 with a follow-up of 11 years. Anthropometric and metabolic variables were measured at baseline and at 6 and 11 years of follow-up. Total testosterone (TT), SHBG and calculated bioT were determined at the 6-year follow-up.Results  The levels of TT and bioT in men were negatively associated with the risk of obesity, T2D and the metabolic syndrome. In women, the levels of TT and bioT were associated positively with the risk of insulin resistance. The levels of SHBG were associated negatively with the risk of T2D, obesity and insulin resistance in both men and women. For all groups, the association was higher at the 11-year follow-up.Conclusions  Low levels of testosterone and SHBG increase the risk of T2D in men, and high levels of testosterone increase the risk of insulin resistance in women. The association between TT levels and the risk of T2D is not completely independent of other variables, such as exposure time, adiposity, insulin resistance or SHBG levels. This study also shows that the different responses between men and women are probably because of the protective effect of SHBG, levels of which are higher in women than in men.
    European Journal of Clinical Investigation 06/2011; 42(1):79 - 85. · 3.37 Impact Factor
  • Clinical Nutrition Supplements 01/2011; 6(1):150-151.
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    ABSTRACT: The elongase of long chain fatty acids family 6 (ELOVL6) is an enzyme that specifically catalyzes the elongation of saturated and monounsaturated fatty acids with 12, 14 and 16 carbons. ELOVL6 is expressed in lipogenic tissues and it is regulated by sterol regulatory element binding protein 1 (SREBP-1). We investigated whether ELOVL6 genetic variation is associated with insulin sensitivity in a population from southern Spain. We undertook a prospective, population-based study collecting phenotypic, metabolic, nutritional and genetic information. Measurements were made of weight and height and the body mass index (BMI) was calculated. Insulin resistance was measured by homeostasis model assessment. The type of dietary fat was assessed from samples of cooking oil taken from the participants' kitchens and analyzed by gas chromatography. Five SNPs of the ELOVL6 gene were analyzed by SNPlex. Carriers of the minor alleles of the SNPs rs9997926 and rs6824447 had a lower risk of having high HOMA_IR, whereas carriers of the minor allele rs17041272 had a higher risk of being insulin resistant. An interaction was detected between the rs6824447 polymorphism and the intake of oil in relation with insulin resistance, such that carriers of this minor allele who consumed sunflower oil had lower HOMA_IR than those who did not have this allele (P = 0.001). Genetic variations in the ELOVL6 gene were associated with insulin sensitivity in this population-based study.
    PLoS ONE 01/2011; 6(6):e21198. · 3.73 Impact Factor
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    ABSTRACT: To study the role of Trp64Arg polymorphism of the ADRB3 gene in the risk of developing hyperuricemia in 1051 subjects from southern Spain, with a followup of 6 years. The inclusion of plasma levels of uric acid as a diagnostic criterion to define the metabolic syndrome is under discussion. Genes responsible for insulin resistance could contribute to the development of hyperuricemia. Previous cross-sectional studies have suggested ADRB3 as a possible candidate gene in the development of hyperuricemia and insulin resistance. A prospective, population-based, cohort study of 1051 persons examined in 1997-98 and reassessed at a second examination 6 years later. The metabolic phenotype was assessed at baseline and again at the followup. Insulin resistance was measured by homeostasis model assessment. The Trp64Arg polymorphism of ADRB3 was detected by real-time polymerase chain reaction. Subjects were considered normouricemic if their serum uric acid levels were <or=7 mg/dl for men or <or= 6 mg/dl for women. Carriers of the Arg64 allele who were normouricemic at baseline had a higher risk of developing hyperuricemia 6 years later (p = 0.017, OR 2.3, 95% CI 1.1-4.6). Multivariate logistic regression analysis showed that the OR of having hyperuricemia at the 6-year followup was significantly associated with the Arg64 allele, after adjusting for age, weight gain, baseline levels of triglycerides, serum uric acid, and insulin resistance (OR 3.1, 95% CI 1.3-7.1). Trp64Arg polymorphism of the ADRB3 gene predicted the risk of developing hyperuricemia in this adult population.
    The Journal of Rheumatology 12/2009; 37(2):417-21. · 3.26 Impact Factor
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    ABSTRACT: The aim of this study was to test the hypothesis of an association between the -30G>A polymorphism of the promoter of the glucokinase gene and the prevalence and incidence of obesity. We studied the -30G>A polymorphism of the glucokinase gene promoter in 981 persons, of whom 866 were seen again 6 years later. All the persons underwent an oral glucose-tolerance test and the BMI (weight/height(2)) was recorded. The -30G>A polymorphism of the glucokinase gene promoter was studied using RFLP-PCR. At the initial study, the probability of having a BMI > or =25 in carriers of the A allele was significantly lower than expected by chance (odds ratio (OR) = 0.63; 95% confidence interval (CI) = 0.456-0.885). In those persons with a BMI > or =30 at the first study, the probability at 6 years of losing weight (reaching a BMI < 30) was greater in carriers of the A allele (OR = 0.22; 95% CI = 0.087-0.576). The increase in weight over these 6 years, taken as a continuous variable, was significantly less only in those persons who were originally obese (P = 0.018). In conclusion, in a population from southern Spain, carriers of the A allele of the -30G>A polymorphism in the promoter of the glucokinase gene had a lower risk for obesity and the likelihood of losing weight was greater in those obese persons who had the A allele (GA or AA).
    Obesity 05/2008; 16(8):1973-5. · 3.92 Impact Factor