Genome-Wide Admixture and Association Study of Serum Selenium Deficiency to Identify Genetic Variants Indirectly Linked to Selenium Regulation in Brazilian Adults.

Blood selenium (Se) concentrations differ substantially by population and could be influenced by genetic variants, increasing Se deficiency-related diseases. We conducted a genome-wide association study (GWAS) to identify single nucleotide polymorphisms (SNPs) associated with serum Se deficiency in 382 adults with admixed ancestry. Genotyping arrays were combined to yield 90,937 SNPs. R packages were applied to quality control and imputation. We also performed the ancestral proportion analysis. The Search Tool for the Retrieval of Interacting Genes was used to interrogate known protein-protein interaction networks (PPIs). Our ancestral proportion analysis estimated 71% of the genome was from Caucasians, 22% was from Africans, and 8% was from East Asians. We identified the SNP rs1561573 in the TraB domain containing 2B (TRABD2B), rs425664 in MAF bZIP transcription factor (MAF), rs10444656 in spermatogenesis-associated 13 (SPATA13), and rs6592284 in heat shock protein nuclear import factor (HIKESHI) genes. The PPI analysis showed functional associations of Se deficiency, thyroid hormone metabolism, NRF2-ARE and the Wnt pathway, and heat stress. Our findings show evidence of a genetic association between Se deficiency and metabolic pathways indirectly linked to Se regulation, reinforcing the complex relationship between Se intake and the endogenous factors affecting the Se requirements for optimal health.

Proposal to Screen for Zinc and Selenium in Patients with IgA Deficiency.

The increase in life expectancy can be a consequence of the world's socioeconomic, sanitary and nutritional conditions. Some studies have demonstrated that individuals with a satisfactory diet variety score present a lower risk of malnutrition and better health status. Zinc and selenium are important micronutrients that play a role in many biochemical and physiological processes of the immune system. Deficient individuals can present both innate and adaptive immunity abnormalities and increased susceptibility to infections. Primary immunodeficiency diseases, also known as inborn errors of immunity, are genetic disorders classically characterized by an increased susceptibility to infection and/or dysregulation of a specific immunologic pathway. IgA deficiency (IgAD) is the most common primary antibody deficiency. This disease is defined as serum IgA levels lower than 7 mg/dL and normal IgG and IgM levels in individuals older than four years. Although many patients are asymptomatic, selected patients suffer from different clinical complications, such as pulmonary infections, allergies, autoimmune diseases, gastrointestinal disorders and malignancy. Knowing the nutritional status as well as the risk of zinc and selenium deficiency could be helpful for the management of IgAD patients. OBJECTIVES: to investigate the anthropometric, biochemical, and nutritional profiles and the status of zinc and selenium in patients with IgAD. METHODS: in this descriptive study, we screened 16 IgAD patients for anthropometric and dietary data, biochemical evaluation and determination of plasma and erythrocyte levels of zinc and selenium. RESULTS: dietary intake of zinc and selenium was adequate in 75% and 86% of the patients, respectively. These results were consistent with the plasma levels (adequate levels of zinc in all patients and selenium in 50% of children, 25% of adolescents and 100% of adults). However, erythrocyte levels were low for both micronutrients (deficiency for both in 100% of children, 75% of adolescents and 25% of adults). CONCLUSION: our results highlight the elevated prevalence of erythrocyte zinc and selenium deficiency in patients with IgAD, and the need for investigation of these micronutrients in their follow-up.

Selenium Content in Freshwater and Marine Fish from Southern Brazil Coastal Plain: a Comparative Analysis on Environmental and Dietary Aspects.

The coastal plain of Rio Grande do Sul is considered to be a Se-deficient region in terms of its population dietary habit, making it the focus of this study. Selenium dietary deficiency is a concern when we consider its potential critical health effects on the local population. Therefore, this study contributes new information on the levels of Se in several species of marine and freshwater fish in the region of the Patos-Mirim Lagoon system, coupled with a comparative analysis of the metalloid contents between both fish groups. The Se contents in the fish species ranged from 88 ± 13 to 688 ± 19 µg.kg-1. The average Se concentration in the muscle tissue of the freshwater species (251 ± 96 µg kg-1) was significantly lower than that of the marine species (412 ± 143 µg kg-1). Likewise, no evidence of Se biomagnification was found among the fish from both the marine and freshwater environments, suggesting the absence of trophic transfer of Se. We note that to ensure that the RDA (Recommended Daily Allowance, 55 µg day-1) of Se dietary intake for adults is met, at least 134 g of freshwater or 82 g of marine fish fillet could be incorporated into the diet of the population of Rio Grande do Sul. According to target hazard quotients (THQ) and the permissible safety limits, consumption of the fish species analyzed is safe for human health.

Low urinary selenium levels are associated with iodine deficiency in Brazilian schoolchildren and adolescents.

BACKGROUND: Selenium (Se) and iodine (Io) are important micronutrients for the proper functioning of the thyroid gland, as they are crucial for the synthesis and activation of the thyroid hormones (TH) triiodothyronine (T3) and thyroxine (T4). OBJECTIVE: To evaluate the Se and Io nutritional status among schoolchildren. METHODOLOGY: Cross-sectional, descriptive and analytical study conducted in 982 schoolchildren aged 6-14 years from public schools in the state of Bahia, Brazil. Sociodemographic and anthropometric variables, as well as urinary Se (USC) and Io concentrations (UIC) using the inductively coupled plasma mass spectrometry (ICP-MS) method and thyroid-stimulating hormone (TSH) from filter paper blood collection, were evaluated. RESULTS: The median USC and UIC were 38.7 and 210.0 (IQR: 26.8-52.9 and 129.3-334.1 µg/L, respectively). The prevalence of iodine deficiency and excessive UIC were observed in 17.1% and 30.9% of schoolchildren, respectively. Concomitant low USC and IoD was found in 3.9% of schoolchildren. There was a positive correlation between USC and UIC (r = 0.60; p = 0.00). The median TSH was 0.95 (IQR: 0.69-1.30 µUI/L). CONCLUSIONS: This study demonstrates that USC is a good biomarker for assessing Se status, meantime more studies are needed to establish cutoff USC in child population. Despite adequate median intake, a subgroup of schoolchildren had IoD and low USC. The correlation between UIC and USC point at the importance of two micronutrients, raising the question whether measuring Se should be included in monitoring programs that address the prevention of nutritional disturbances.

Zinc and selenium indicators and their relation to immunologic and metabolic parameters in male patients with human immunodeficiency virus.

OBJECTIVES: Micronutrient deficiencies are common among people living with HIV (PLWHIV). The clinical and immunologic consequences of micronutrient deficiencies have been poorly explored in the context of human immunodeficiency virus (HIV) infection. The aim of this study was to determine the prevalence of zinc and selenium deficiency (dietary intake and serum concentrations) and analyze their associations with absolute CD4+ T-cell counts, inflammation markers, and metabolic disorders in a cohort of antiretroviral-experienced HIV-infected individuals. METHODS: The zinc and selenium intakes of 124 HIV-infected men were estimated using 3-d food records. In a subcohort of 45 individuals, serum zinc and selenium concentrations and proinflammatory cytokines were determined. Body composition, bone mineral density (BMD), CD4+ T-cell counts, lipid profile, glucose, and blood pressure were determined and were associated with zinc and selenium dietary intake and serum concentrations. RESULTS: Of the PLWHIV studied, 58% had suboptimal intake of zinc and 8% demonstrated suboptimal intake of selenium. Serum deficiencies for zinc and selenium were 23.9% and 65.9%, respectively. Zinc and selenium intake were correlated with increased muscle mass. Selenium intake was associated with increased BMD of the lumbar region. An inverse correlation between serum selenium concentration and several proinflammatory cytokines (interleukin-1ß, interleukin-6, and tumor necrosis factor-α) was found. CONCLUSION: Suboptimal zinc and selenium intake and serum concentration deficiencies are highly prevalent in treated HIV-positive individuals and are associated with body composition, BMD, and inflammation. Clinical trials should be designed to explore the effect of zinc and selenium supplementation on metabolic, inflammatory, and immunologic parameters on the HIV-positive population.

Rhabdomyolysis in water buffaloes (Bubalus bubalis)

Rhabdomyolysis is a myopathy characterized by severe acute myonecrosis with lysis of muscle cells and extravasation of its content into the bloodstream, causing a secondary renal failure and myoglobinuria. Case-reports have been documented in a wide range of wild or domestic animal species, but to our knowledge, no reports in water buffaloes (Bubalus bubalis) have been done. Three animals had signs of paralysis, muscle tremors and myoglobinuria while others died spontaneously. Samples of blood from affected animals showed increased levels of creatin kinase (CK), potassium (K), aspartate transaminase (AST), and lactate dehydrogenase (LDH). In addition, Selenium (Se) levels of those animals were low. Necropsy findings consisted of severe gelatinous and yellowish edema and pallor of the skeletal muscles of the hind limbs, lumbar, cervical and scapular region. Microscopically, acute and severe segmental monophasic coagulative necrosis of skeletal muscles and acute pigmentary tubular nephrosis was observed. We suspect that selenium deficiency was a predisposing factor of rhabdomyolysis in this particular case.(AU)

Rhabdomyolysis in water buffaloes (Bubalus bubalis)

Rhabdomyolysis is a myopathy characterized by severe acute myonecrosis with lysis of muscle cells and extravasation of its content into the bloodstream, causing a secondary renal failure and myoglobinuria. Case-reports have been documented in a wide range of wild or domestic animal species, but to our knowledge, no reports in water buffaloes (Bubalus bubalis) have been done. Three animals had signs of paralysis, muscle tremors and myoglobinuria while others died spontaneously. Samples of blood from affected animals showed increased levels of creatin kinase (CK), potassium (K), aspartate transaminase (AST), and lactate dehydrogenase (LDH). In addition, Selenium (Se) levels of those animals were low. Necropsy findings consisted of severe gelatinous and yellowish edema and pallor of the skeletal muscles of the hind limbs, lumbar, cervical and scapular region. Microscopically, acute and severe segmental monophasic coagulative necrosis of skeletal muscles and acute pigmentary tubular nephrosis was observed. We suspect that selenium deficiency was a predisposing factor of rhabdomyolysis in this particular case.