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- Para Além da Falta de Iodo: O Papel do Ambiente no HipotiroidismoPublication . Coelho, Nádia; Garcia, Patrícia; Rodrigues, ArmindoA tiroide é uma glândula do sistema endócrino em forma de borboleta situada na parte anterior do pescoço, logo à frente da traqueia (figura 1). Esta glândula encarrega-se de produzir as hormonas tetraiodotironina (tiroxina ou T4) e triiodotironina (T3). As hormonas da tiroide atuam sobre vários aspetos do metabolismo: questões como o desenvolvimento neuronal, ritmo cardíaco, ritmo respiratório, função muscular, função digestiva, manutenção dos ossos, etc., são todas controladas pela ação da T4 e da T3. Neste sentido, a perturbação do equilíbrio destas hormonas acarreta consequências para todo o organismo. A produção hormonal dá-se ao nível celular dos folículos tiroideus, os quais consistem numa camada epitelial de células cuboides disposta em forma de esfera, e em cujo interior se encontra o coloide – local onde é armazenada a proteína tiroglobulina. É a tiroglobulina que permite a síntese de T4 e T3 pelas células foliculares quando necessário.
- Histological evidence of hypothyroidism in mice chronically exposed to conventional farmingPublication . Coelho, Nádia; Camarinho, Ricardo; Garcia, Patrícia; Rodrigues, ArmindoWorldwide, disorders of the thyroid gland are a growing concern; such can be caused by exposure to contaminants, including agrochemicals used in conventional agriculture, which act as endocrine disruptors. The purpose of this study is to evaluate whether or not exposure to an environment with conventional agriculture leads to thyroid disruption. Mus musculus were used as bioindicator species, captured in two sites: a farm where conventional agriculture is practiced, and a place without agriculture. Thyroid histomorphometric and morphologic data were analyzed. The impacts of the agricultural environment over the thyroid were revealed, as indications of hypothyroidism were observed in exposed mice: the area and volume of epithelial cells were much lower. Alterations in thyroid histomorphology were also observed: lower follicular sphericity, irregularly delimited epithelium and increased exfoliation into the colloid. These results highlight the need for transition from current conventional agricultural systems towards organic systems.
- Concerning Mercury (Hg) Levels in the Hair of Children Inhabiting a Volcanically Active AreaPublication . Fontes, Rute; Coelho, Nádia; Garcia, Patrícia; Bernardo, Filipe; dos Santos Rodrigues, Armindo; Caudle, MichaelABSTRACT: Gaseous elemental mercury (Hg0 or GEM) is an atmospheric form of mercury (Hg)—a toxic heavy metal—that is naturally released in volcanic environments. Research with wild mice demonstrates that chronic exposure to a hydrothermal volcanic environment leads to the bioaccumulation of Hg in the lungs, but also in both the central (CNS) and peripheric (PNS) nervous systems, with marked indications of neurotoxicity. Studies addressing human exposure to volcanogenic Hg0 are scarce, hence its risks are still unknown. This study aims to evaluate the level of exposure to Hg0 in children living in a volcanically active environment. Methodology and main findings: Two groups of school-aged children (from 6 to 9 years old) were part of this study: one with children inhabiting a hydrothermal area (exposed group) and another with children inhabiting an area without volcanic activity (non-exposed group). Hair samples were collected from each individual for Hg level analysis. It was found that the levels of Hg in the hair of exposed children were 4.2 times higher than in that of non-exposed children (≈1797.84 ± 454.92 ppb vs. 430.69 ± 66.43 ppb, respectively). Conclusion: Given the vast health risks Hg poses, the need to monitor the health of populations inhabiting volcanically active areas is highlighted. Because little is known about the fate, modifications, and effects of Hg0 in the human body, particularly regarding its effects on the nervous system in children, the development of further research within the scope is strongly encouraged.
- Volcanic environments and thyroid disruption – A review focused on As, Hg, and CoPublication . Coelho, Nádia; Bernardo, Filipe; dos Santos Rodrigues, Armindo; Garcia, Patrícia; Wei, OuyangABSTRACT: The purpose of this review is to explore the link between volcanic environments and thyroid disruption, with focus on the role played by As, Hg, and Co. Volcanoes are the most well-known source of natural pollution, enriching the environment in hazardous elements. It is estimated that about 10 % of world population lives near active volcanoes (Brown et al., 2015). There is evidence supporting a link between living in volcanic environments and thyroid cancer, but it is likely that other types of thyroid disruption are also exacerbated in the populations inhabiting volcanic areas. Arsenic (As) and mercury (Hg) are elements with toxic properties that are present in volcanic environments. Cobalt (Co), which is also present in these environments, is part of the essential cobalamin vitamin (B12). However, exposure to non-cobalamin Co can pose health risks. The effects of these three elements on the thyroid are understudied. A review of 125 publications retrieved from the Web of Science, PubMed, and Scopus databases, covering year 1955 to present, was performed. The known molecular mechanisms underlying thyroid disruption by these elements are discussed. It was found that thyroid cancer incidence, but also that of hypothyroidism are heightened in populations living in volcanic environments, particularly in Iceland, Hawaii, and Italy. Knowledge gaps regarding (i) thyroid disruption in areas with non-eruptive active volcanism, (ii) the toxic effects of As, Hg, and Co on the thyroid, and (iii) the incidence of hypothyroidism and other thyroid pathologies in volcanic environments are highlighted. The need to monitor the population of volcanic areas in terms of health is accentuated.
- Histological Evidence of Thyroid Disruption in Wild Mice from Conventional and Organic Farming EnvironmentsPublication . Coelho, Nádia; Carminho, Ricardo; Garcia, Patrícia; Bernardo, Filipe; dos Santos Rodrigues, Armindo; Fortin, ClaudeABSTRACT: The main objective of this work is to assess the potential negative impact of organic farming on the thyroid gland and compare it with the negative impact of conventional farming on this organ. Previous studies have linked exposure to conventional farming with thyroid disruption; relatively less is known about effects of exposure to organic farming on the thyroid. Mus musculus were the bioindicators in this work, captured in a conventional farm (CF), an organic farm (OF), and two reference areas (RF’) without agriculture. Histomorphometric and histomorphological measurements of the thyroid were performed. Hypothyroidism signs were observed in mice exposed to either farming system, being less pronounced in organic farming-exposed mice: epithelium thickness and the epithelial cells’ area and volume were lower than in non-exposed mice [epithelium thickness (µm): 4.16 ± 0.51 (CF); 6.28 ± 0.19 (OF); 7.46 ± 0.25 (RF’)]. Histomorphologic alterations included decreased follicular sphericity, increased epithelium irregularity, increased exfoliation into the colloid, and increased inflammation of thyroid tissue. Results suggest that, while organic farming might be a better alternative to conventional farming, it is not completely free of health hazards. Exposure to an organic farming environment can cause thyroid disruption, although with less pronounced effects than conventional farming. Despite there being risks to be considered, results support the benefit of transitioning from conventional farming systems towards organic farming systems.