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Selenoproteins in human body: focus on thyroid pathophysiology.
Hormones (Athens) 2018; 17(2):183-196H

Abstract

Selenium (Se) has a multilevel, complex and dynamic effect on the human body as a major component of selenocysteine, incorporated into selenoproteins, which include the selenocysteine-containing enzymes iodothyronine deiodinases. At the thyroid level, these proteins play an essential role in antioxidant protection and hormone metabolism. This is a narrative review based on PubMed/Medline database research regarding thyroid physiology and conditions with Se and Se-protein interferences. In humans, Se-dependent enzyme functions are best expressed through optimal Se intake, although there is gap in our knowledge concerning the precise mechanisms underlying the interrelation. There is a good level of evidence linking low serum Se to autoimmune thyroid diseases and, to a lesser extent, differentiated thyroid cancer. However, when it comes to routine supplementation, the results are heterogeneous, except in the case of mild Graves' orbitopathy. Autoimmune hypothyroidism is associated with a state of higher oxidative stress, but not all studies found an improvement of thyroid function after Se was introduced as antioxidant support. Meanwhile, no routine supplementation is recommended. Low Se intake is correlated with an increased risk of developing antithyroid antibodies, its supplementation decreasing their titres; there is also a potential reduction in levothyroxine replacement dose required for hypothyroidism and/or the possibility that it prevents progression of subclinical hypothyroidism, although not all studies agree. In thyroid-associated orbitopathy, euthyroidism is more rapidly achieved if the micronutrient is added to traditional drugs, while controls appear to benefit from the microelement only if they are deficient; thus, a basal assay of Se appears advisable to better select patients who need substitution. Clearly, further Se status biomarkers are required. Future introduction of individual supplementation algorithms based on baseline micronutrient levels, underlying or at-risk clinical conditions, and perhaps selenoprotein gene polymorphisms is envisaged.

Authors+Show Affiliations

Department of Endocrinology, Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania. ana74us@yahoo.com. Endocrinology Clinic, Clinical County Hospital, Cluj-Napoca, Romania. ana74us@yahoo.com. , Cluj-Napoca, Romania. ana74us@yahoo.com.Department of Endocrinology, Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania. Endocrinology Clinic, Clinical County Hospital, Cluj-Napoca, Romania.

Pub Type(s)

Journal Article
Review

Language

eng

PubMed ID

29873029

Citation

Valea, Ana, and Carmen Emanuela Georgescu. "Selenoproteins in Human Body: Focus On Thyroid Pathophysiology." Hormones (Athens, Greece), vol. 17, no. 2, 2018, pp. 183-196.
Valea A, Georgescu CE. Selenoproteins in human body: focus on thyroid pathophysiology. Hormones (Athens). 2018;17(2):183-196.
Valea, A., & Georgescu, C. E. (2018). Selenoproteins in human body: focus on thyroid pathophysiology. Hormones (Athens, Greece), 17(2), pp. 183-196. doi:10.1007/s42000-018-0033-5.
Valea A, Georgescu CE. Selenoproteins in Human Body: Focus On Thyroid Pathophysiology. Hormones (Athens). 2018;17(2):183-196. PubMed PMID: 29873029.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Selenoproteins in human body: focus on thyroid pathophysiology. AU - Valea,Ana, AU - Georgescu,Carmen Emanuela, Y1 - 2018/06/05/ PY - 2017/10/16/received PY - 2018/04/18/accepted PY - 2018/6/7/pubmed PY - 2019/5/21/medline PY - 2018/6/7/entrez KW - Chronic autoimmune Hashimoto’s thyroiditis KW - Differentiated thyroid cancer KW - Graves’ disease KW - Iodothyronine deiodinases KW - Malignancy KW - Orbitopathy KW - Selenium KW - Selenocysteine KW - Selenoproteins SP - 183 EP - 196 JF - Hormones (Athens, Greece) JO - Hormones (Athens) VL - 17 IS - 2 N2 - Selenium (Se) has a multilevel, complex and dynamic effect on the human body as a major component of selenocysteine, incorporated into selenoproteins, which include the selenocysteine-containing enzymes iodothyronine deiodinases. At the thyroid level, these proteins play an essential role in antioxidant protection and hormone metabolism. This is a narrative review based on PubMed/Medline database research regarding thyroid physiology and conditions with Se and Se-protein interferences. In humans, Se-dependent enzyme functions are best expressed through optimal Se intake, although there is gap in our knowledge concerning the precise mechanisms underlying the interrelation. There is a good level of evidence linking low serum Se to autoimmune thyroid diseases and, to a lesser extent, differentiated thyroid cancer. However, when it comes to routine supplementation, the results are heterogeneous, except in the case of mild Graves' orbitopathy. Autoimmune hypothyroidism is associated with a state of higher oxidative stress, but not all studies found an improvement of thyroid function after Se was introduced as antioxidant support. Meanwhile, no routine supplementation is recommended. Low Se intake is correlated with an increased risk of developing antithyroid antibodies, its supplementation decreasing their titres; there is also a potential reduction in levothyroxine replacement dose required for hypothyroidism and/or the possibility that it prevents progression of subclinical hypothyroidism, although not all studies agree. In thyroid-associated orbitopathy, euthyroidism is more rapidly achieved if the micronutrient is added to traditional drugs, while controls appear to benefit from the microelement only if they are deficient; thus, a basal assay of Se appears advisable to better select patients who need substitution. Clearly, further Se status biomarkers are required. Future introduction of individual supplementation algorithms based on baseline micronutrient levels, underlying or at-risk clinical conditions, and perhaps selenoprotein gene polymorphisms is envisaged. SN - 2520-8721 UR - https://www.unboundmedicine.com/medline/citation/29873029/Selenoproteins_in_human_body:_focus_on_thyroid_pathophysiology_ L2 - https://link.springer.com/article/10.1007/s42000-018-0033-5 DB - PRIME DP - Unbound Medicine ER -