title: A randomized-controlled, double-blind study of the impact of selenium supplementation on thyroid autoimmunity and inflammation with focus on the GPx1 genotypes.
abstract: OBJECTIVE
  To analyze the impact of selenium supplementation on serum antiTPO levels and thyroid echogenicity in patients with CAT, evaluating the response in subgroups with different GPx1 genotypes.
  
  
  METHODS
  CAT patients (n = 55) with positive antiTPO were randomized to selenomethionine (SeMet) 200 μg daily (n = 28) or placebo (n = 27) for 3 months. Assessments included GPx1 genotyping at baseline and serum levels of plasma selenium, erythrocyte GPx1 activity, antiTPO and thyroid echogenicity at baseline, and 3 and 6 months.
  
  
  RESULTS
  In the SeMet group, the increase in plasma levels of selenium and erythrocyte GPx1 activity was similar among patients with different GPx1 genotypes. In the overall cohort, patients randomized to SeMet showed a 5 % decrease in antiTPO levels at 3 months (p = non-significant) and 20 % at 6 months (p < 0.001 versus 3 months). In contrast, patients in the placebo group did not show significant changes in antiTPO levels at any time point. Subgroup analysis showed that patients with different GPx1 genotypes presented comparable responses in antiTPO levels and echogenicity index to SeMet.
  
  
  CONCLUSIONS
  Selenium supplementation decreased serum antiTPO levels in CAT patients, with similar response among patients with different GPx1 genotypes.
authors.affiliation: Thyroid Unit and Laboratory of Cellular and Molecular Biology (LIM-25), Division of Endocrinology and Metabolism, University of São Paulo Medical School, Hospital das Clínicas, Av. Dr. Enéas de Carvalho Aguiar, 155, 8th floor, bl 3, PAMB, São Paulo, SP, 05403-900, Brazil. cleyrocha@uol.com.br.
authors.forename: C R
authors.initials: CR
authors.lastname: de Farias
authors.affiliation: Department of Food and Experimental Nutrition, Faculty of Pharmaceutical Science, University of São Paulo, Av. Prof. Lineu Prestes 580, bl 14, Cidade Universitária, São Paulo, SP, 05508-000, Brazil. baritacardoso@gmail.com.
authors.forename: B R
authors.initials: BR
authors.lastname: Cardoso
authors.affiliation: Ultrasound Unit, Department of Radiology, University of São Paulo Medical School, Hospital das Clínicas, Av Dr Enéas de Carvalho Aguiar, 255, 3rd floor, Unit 013, São Paulo, SP, 05403-900, Brazil. giovannambo@hotmail.com.
authors.forename: G M B
authors.initials: GM
authors.lastname: de Oliveira
authors.affiliation: Laboratory of Cellular and Molecular Endocrinology, LIM-25, Division of Endocrinology and Metabolism, University of São Paulo Medical School, Av. Dr. Arnaldo 455, 4th floor, Units 4305/4307, São Paulo, SP, 01246-903, Brazil. belmello@usp.br.
authors.forename: I C
authors.initials: IC
authors.lastname: de Mello Guazzelli
authors.affiliation: Hematology and Biochemistry, Center of Pathology, Adolpho Lutz Institute, Av. Dr. Arnaldo 351, 7th floor, São Paulo, SP, 01246-000, Brazil. rmcatarino@yahoo.com.br.
authors.forename: R M
authors.initials: RM
authors.lastname: Catarino
authors.affiliation: Ultrasound Unit, Department of Radiology, University of São Paulo Medical School, Hospital das Clínicas, Av. Dr. Enéas de Carvalho Aguiar, 255, 3rd floor, Unit 013, São Paulo, SP, 05403-010, Brazil. mcchammas@hotmail.com.
authors.forename: M C
authors.initials: MC
authors.lastname: Chammas
authors.affiliation: Department of Food and Experimental Nutrition, Faculty of Pharmaceutical Science, University of São Paulo, Av. Prof. Lineu Prestes 580, bl 14, Cidade Universitária, São Paulo, SP, 05508-000, Brazil. smfcozzo@usp.br.
authors.forename: S M F
authors.initials: SM
authors.lastname: Cozzolino
authors.affiliation: Thyroid Unit and Laboratory of Cellular and Molecular Biology (LIM-25), Division of Endocrinology and Metabolism, University of São Paulo Medical School, Hospital das Clínicas, Av. Dr. Enéas de Carvalho Aguiar, 155, 8th floor, bl 3, PAMB, São Paulo, SP, 05403-900, Brazil. meyer.knobel@hc.fm.usp.br.
authors.forename: M
authors.initials: M
authors.lastname: Knobel
mesh_terms: D000328:Adult; D015551:Autoimmunity / Q000187:drug effects*; D019587:Dietary Supplements; D004311:Double-Blind Method; D005260:Female; D005838:Genotype; D005979:Glutathione Peroxidase / Q000235:genetics*; D006801:Humans; D007249:Inflammation / Q000188:drug therapy / Q000235:genetics / Q000276:immunology; D007453:Iodide Peroxidase / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D012645:Selenomethionine / Q000008:administration & dosage / Q000627:therapeutic use*; D013961:Thyroid Gland / Q000187:drug effects* / Q000276:immunology; D013967:Thyroiditis, Autoimmune / Q000188:drug therapy* / Q000235:genetics / Q000276:immunology; D016896:Treatment Outcome; D055815:Young Adult; D000094765:Glutathione Peroxidase GPX1
chemical_list: D012645:Selenomethionine; D007453:Iodide Peroxidase; D005979:Glutathione Peroxidase; D000094765:Glutathione Peroxidase GPX1; C000722067:GPX1 protein, human
keywords: Autoimmunity; Genetic; Glutathione peroxidase GPx1; Polymorphism; Selenium; Thyroid gland