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Relevance of selenoprotein transcripts for selenium status in humans.

Reszka E, Jablonska E, Gromadzinska J, Wasowicz W - Genes Nutr (2011)

Bottom Line: Studies on rats suggest that whole blood selenoprotein mRNA level can be used as the relevant molecular biomarker for assessing Se status, and suboptimal Se intake may be sufficient to achieve effective expression.Human studies, however, did not confirm this hypothesis.The use of selenoprotein transcripts as a molecular biomarker of Se status requires further studies on a large group of healthy individuals with different baseline Se, including data regarding genetic polymorphism of selenoproteins and data regarding potential modifiers of Se metabolism.

View Article: PubMed Central - PubMed

Affiliation: Department of Toxicology and Carcinogenesis, Nofer Institute of Occupational Medicine, 8 Teresy St., 91-348, Lodz, Poland.

ABSTRACT
The most commonly used methods for assessing the selenium (Se) status in humans involve analysis of Se concentration, selenoprotein activity, and concentration in the blood and its compartments. Recently, it has been suggested that the expression of selenoprotein mRNA in circulating blood leukocytes could differently reflect Se status, due to prioritization of specific selenoprotein synthesis in response to dietary Se supply. Whereas the Se levels required for optimization of selenoprotein P level and plasma glutathione peroxidise activity are well known, estimation of Se level that is required for maximal mRNA expression of selenoprotein in humans is the subject of current investigations. Studies on rats suggest that whole blood selenoprotein mRNA level can be used as the relevant molecular biomarker for assessing Se status, and suboptimal Se intake may be sufficient to achieve effective expression. Human studies, however, did not confirm this hypothesis. According to studies on rodents and humans discussed in this review, it appears that suboptimal Se intake may be sufficient to satisfy molecular requirements of Se and it is lower than current recommended dietary intake in humans. The use of selenoprotein transcripts as a molecular biomarker of Se status requires further studies on a large group of healthy individuals with different baseline Se, including data regarding genetic polymorphism of selenoproteins and data regarding potential modifiers of Se metabolism.

No MeSH data available.


Biomarkers of selenium status in humans. A scheme of traditional and molecular biomarkers measurements with the impact of potential modifiers (physiological, environmental, genetic). The optimal selenium biomarker should reflect all putative egzo- and endogenous factors which can modulate selenium bioavailability, metabolism and selenoprotein transcription, biosynthesis, transport, activity and function. A type of measurement used for the determination of selenium status should be also considered
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Fig2: Biomarkers of selenium status in humans. A scheme of traditional and molecular biomarkers measurements with the impact of potential modifiers (physiological, environmental, genetic). The optimal selenium biomarker should reflect all putative egzo- and endogenous factors which can modulate selenium bioavailability, metabolism and selenoprotein transcription, biosynthesis, transport, activity and function. A type of measurement used for the determination of selenium status should be also considered

Mentions: Functional significance of blood Se status is mainly related to selenoprotein activity in specific tissues. Therefore, both traditional and molecular biomarkers of Se status measured in different human tissues, except for controlled Se intake, may depend on additional major modifiers, like health status (e.g., endocrine and immunological status), inter-individual variations (age, sex, genetic polymorphism), environmental exposure, diet, medication, etc. (Fig. 2). Therefore, establishing the Se status and intake which would be optimal for human health seems to be very difficult, especially in many populations experiencing suboptimal Se supply, including Europe. Epidemiological and animal studies clearly indicate that biological effects of Se are sex-specific, which may be associated with endocrine regulation and also immunological status. It has been suggested that cancer risk in men is more profoundly influenced by Se status than in women (Waters et al. 2004). Selenoprotein gene expression displays sexual dimorphism in various organs of females and males, e.g., Se status was linked to male fertility due to GPx4 function during spermatogenesis (Schomburg and Schweizer 2009). Sex-specific selenoprotein expression pattern may vary or be sustained with age. In the SELGEN study, an effect of Se supplementation was associated with GPx4 genetic polymorphism in a sex-specific manner (Meplan et al. 2008). Plasma Se level is not likely to accurately reflect tissue Se status or selenoenzyme activity and level. There are several confounders potentially influencing Se level. Liver and kidney diseases can cause alterations of SePP1 (Li et al. 2007) and GPx3 levels (Zachara et al. 2006). Se metabolism may be altered in different health pathologies, e.g., in patients with inflammatory diseases. During critical illness, like sepsis, acute phase response, and other immunological disturbances, serum Se status may be lower and insufficient to support organ function. In systemic inflammatory response syndrome patients, serum Se concentration was significantly lower (Vincent and Forceville 2008). Tobacco smoking or occupational exposure can also increase dietary requirement of Se. It is generally agreed that smoking can decrease the activity of antioxidative selenoproteins, probably due to formation of complexes of Se with cadmium (Ellingsen et al. 2009).Fig. 2


Relevance of selenoprotein transcripts for selenium status in humans.

Reszka E, Jablonska E, Gromadzinska J, Wasowicz W - Genes Nutr (2011)

Biomarkers of selenium status in humans. A scheme of traditional and molecular biomarkers measurements with the impact of potential modifiers (physiological, environmental, genetic). The optimal selenium biomarker should reflect all putative egzo- and endogenous factors which can modulate selenium bioavailability, metabolism and selenoprotein transcription, biosynthesis, transport, activity and function. A type of measurement used for the determination of selenium status should be also considered
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3316749&req=5

Fig2: Biomarkers of selenium status in humans. A scheme of traditional and molecular biomarkers measurements with the impact of potential modifiers (physiological, environmental, genetic). The optimal selenium biomarker should reflect all putative egzo- and endogenous factors which can modulate selenium bioavailability, metabolism and selenoprotein transcription, biosynthesis, transport, activity and function. A type of measurement used for the determination of selenium status should be also considered
Mentions: Functional significance of blood Se status is mainly related to selenoprotein activity in specific tissues. Therefore, both traditional and molecular biomarkers of Se status measured in different human tissues, except for controlled Se intake, may depend on additional major modifiers, like health status (e.g., endocrine and immunological status), inter-individual variations (age, sex, genetic polymorphism), environmental exposure, diet, medication, etc. (Fig. 2). Therefore, establishing the Se status and intake which would be optimal for human health seems to be very difficult, especially in many populations experiencing suboptimal Se supply, including Europe. Epidemiological and animal studies clearly indicate that biological effects of Se are sex-specific, which may be associated with endocrine regulation and also immunological status. It has been suggested that cancer risk in men is more profoundly influenced by Se status than in women (Waters et al. 2004). Selenoprotein gene expression displays sexual dimorphism in various organs of females and males, e.g., Se status was linked to male fertility due to GPx4 function during spermatogenesis (Schomburg and Schweizer 2009). Sex-specific selenoprotein expression pattern may vary or be sustained with age. In the SELGEN study, an effect of Se supplementation was associated with GPx4 genetic polymorphism in a sex-specific manner (Meplan et al. 2008). Plasma Se level is not likely to accurately reflect tissue Se status or selenoenzyme activity and level. There are several confounders potentially influencing Se level. Liver and kidney diseases can cause alterations of SePP1 (Li et al. 2007) and GPx3 levels (Zachara et al. 2006). Se metabolism may be altered in different health pathologies, e.g., in patients with inflammatory diseases. During critical illness, like sepsis, acute phase response, and other immunological disturbances, serum Se status may be lower and insufficient to support organ function. In systemic inflammatory response syndrome patients, serum Se concentration was significantly lower (Vincent and Forceville 2008). Tobacco smoking or occupational exposure can also increase dietary requirement of Se. It is generally agreed that smoking can decrease the activity of antioxidative selenoproteins, probably due to formation of complexes of Se with cadmium (Ellingsen et al. 2009).Fig. 2

Bottom Line: Studies on rats suggest that whole blood selenoprotein mRNA level can be used as the relevant molecular biomarker for assessing Se status, and suboptimal Se intake may be sufficient to achieve effective expression.Human studies, however, did not confirm this hypothesis.The use of selenoprotein transcripts as a molecular biomarker of Se status requires further studies on a large group of healthy individuals with different baseline Se, including data regarding genetic polymorphism of selenoproteins and data regarding potential modifiers of Se metabolism.

View Article: PubMed Central - PubMed

Affiliation: Department of Toxicology and Carcinogenesis, Nofer Institute of Occupational Medicine, 8 Teresy St., 91-348, Lodz, Poland.

ABSTRACT
The most commonly used methods for assessing the selenium (Se) status in humans involve analysis of Se concentration, selenoprotein activity, and concentration in the blood and its compartments. Recently, it has been suggested that the expression of selenoprotein mRNA in circulating blood leukocytes could differently reflect Se status, due to prioritization of specific selenoprotein synthesis in response to dietary Se supply. Whereas the Se levels required for optimization of selenoprotein P level and plasma glutathione peroxidise activity are well known, estimation of Se level that is required for maximal mRNA expression of selenoprotein in humans is the subject of current investigations. Studies on rats suggest that whole blood selenoprotein mRNA level can be used as the relevant molecular biomarker for assessing Se status, and suboptimal Se intake may be sufficient to achieve effective expression. Human studies, however, did not confirm this hypothesis. According to studies on rodents and humans discussed in this review, it appears that suboptimal Se intake may be sufficient to satisfy molecular requirements of Se and it is lower than current recommended dietary intake in humans. The use of selenoprotein transcripts as a molecular biomarker of Se status requires further studies on a large group of healthy individuals with different baseline Se, including data regarding genetic polymorphism of selenoproteins and data regarding potential modifiers of Se metabolism.

No MeSH data available.