Research CommunicationsGlutathione Peroxidase, Selenoprotein P and Selenium in Serum of Elderly Subjects in Relation to Other Biomarkers of Nutritional Status and Food Intake☆
Introduction
The concentration of selenium in plasma or blood is often used as an index of selenium status in epidemiologic and clinical studies.1, 2, 3, 4, 5, 6The plasma level responds more rapidly to changes in selenium balance than the blood level. The interpretation of such changes is complicated by the fact that the chemical composition of selenium compounds in plasma and erythrocytes is only partly known. It has been established for some time that extracellular glutathione peroxidase (eGSHPx) is a selenoprotein in plasma,[7]and recently another selenoprotein, selenoprotein P, has been found in human plasma, accounting for a large part of plasma selenium.[8]Radioimmunoassays have been developed to measure these proteins.8, 9, 10
The concentration of selenium and selenoproteins in tissues can be influenced by selenium intake,11, 12, 13but the relation of the intake of different foods to selenium and selenoprotein concentrations in humans is incompletely known. There is also a need to assess the influence of other life-style variables than dietary intake on biomarkers of selenium status. Moreover, because glutathione peroxidases and maybe other selenoproteins are believed to act as components of the oxidant defence, their interaction with other antioxidants needs further study. In the present study the mutual relationships of eGSHPx, selenoprotein P, and selenium in serum, and selenium in urine were investigated. In addition their associations to dietary intake, some life-style variables and serum antioxidant levels were studied.
Section snippets
Study Design
Nine hundred subjects (50 to 69 years old) living in Malmö were randomly selected from the population register and invited to participate in the study as described in detail elsewhere.14, 15, 16To screen the subjects for inclusion in the study, they completed a medical questionnaire and underwent a medical examination, including assays of clinical-chemical variables. Of the 900 subjects, 552 (61%) took part in this health survey.[15]Nineteen subjects were excluded for medical reasons or because
Selenium Intake and Selenium Status
The dietary selenium intake was higher in men than in women and the difference was similar at all sampling times (Table 1). The geometric mean ratio (95% CI) men/women with respect to the mean intake at six recording periods was 1.26 (1.15, 1.38), but the energy-adjusted selenium intake was not significantly different in men and women (ratio: 1.00 (0.92, 1.09)). Men had a significantly lower concentration of serum selenium, and the mean from six samplings for men was 6% lower than that of
Discussion
The established metabolic role of selenium in mammalian species is tied to its presence in selenocysteine residues in specific selenoproteins. One of them, eGSHPx, catalyzes the reduction of different hydroperoxides using glutathione or the thioredoxin and glutaredoxin systems as electron donors.7, 23The function of the other selenoprotein demonstrated in human plasma, selenoprotein P, is unknown, but it may be involved in the oxidant defense.[24]This study examines the use of the serum levels
Acknowledgements
The study was planned by a working group at the Swedish Medical Research Council, and we thank Prof. H. Danielsson for his support during the initiation of the study. Ms. E. Callmer, Ms. I. Malmquist and Ms. I. Mattisson supervised the contacts with the subjects and administered the dietary assessment procedures. Ms. B. Ekström, Ms. B. Mårtensson, and Ms. B. Mattsson gave skilful assistance in the analytical work. Dr. U. Strömberg gave much valuable statistical advice.
References (48)
- et al.
Biochemical studies of a selenium-deficient population in Chinameasurement of selenium, glutathione peroxidase and other oxidant defense indices in blood
J. Nutr.
(1989) - et al.
Serum selenium concentration and risk of ischaemic heart disease in a prospective cohort study of 3000 males
Atherosclerosis
(1992) - et al.
Antihuman plasma glutathione peroxidase antibodiesImmunologic investigations to determine plasma glutathione peroxidase protein and selenium content in plasma
Blood
(1989) - et al.
Purification of selenoprotein P from human plasma
Biochim. Biophys. Acta
(1994) - et al.
Radioimmunoassay of glutathione peroxidase in human serum
Clin. Chim. Acta
(1993) - et al.
Evidence for specific selenium target tissues and new biologically important selenoproteins
Biochim. Biophys. Acta
(1988) - et al.
The thioredoxin and glutaredoxin system are efficient electron donors to human plasma glutathione peroxidase
J. Biol. Chem.
(1994) - et al.
Pathogenesis of diquat-induced liver necrosis in selenium-deficient ratsAssessment of the roles of lipid peroxidation and selenoprotein P
Hepatology
(1995) - et al.
Selenium intake, age, gender, and smoking in relation to indices of selenium status of adults residing in a seleniferous area
Am. J. Clin. Nutr.
(1990) Effect of ethanol use and other lifestyle variables on measures of selenium status
Alcohol
(1991)
Selenium status, fatty acids, vitamins A and E, and agingThe Nove Study
Am. J. Clin. Nutr.
Extracellular glutathione peroxidase and ascorbic acid in aqueous humor and serum of patients operated on for cataract
Clin. Chim. Acta
Selenoprotein P concentration in plasma as an index of selenium status in selenium-deficient and selenium-supplemented Chinese subjects
J. Nutr.
Fish as a source of exposure to mercury and selenium
Sci. Total Environ.
Factors related to the plasma fatty acid profile in healthy subjects, with special reference to antioxidant micronutrient statusA multivariate analysis
Am. J. Clin. Nutr.
Selenium in human urineconcentrations levels and medical implications
Clin. Chim. Acta
Trace element status in healthy subjects switching from a mixed to a lactovegetarian diet for 12 months
Am. J. Clin. Nutr.
Urinary excretion of selenium by New Zealand and North American human subjects on different intakes
Am. J. Clin. Nutr.
Low plasma selenium as a risk factor for cancer death in middle-aged men
Nutr. Cancer
Serum selenium and subsequent risk of cancer among Finnish men and women
J. Natl. Cancer Inst.
Serum retinol, beta-carotene, vitamin E, and selenium as related to subsequent cancer of specific sites
Am. J. Epidemiol.
SeleniumClinical significance and analytical concepts
Crit. Rev. Clin. Lab. Sci.
Selenoprotein P in serum as a biochemical marker of selenium status
Analyst
Regulation of selenoproteins
Annu. Rev. Nutr.
Cited by (16)
Serum selenium levels, the selenoprotein glutathione peroxidase and vascular protection: The SABPA study
2018, Food Research InternationalCitation Excerpt :These findings contradict the findings of the present study where white women had the highest selenium levels. However, in another study it was found that in 50–69 year old men and women this association was evident only in men and not in women (Åkesson et al., 1997), which may indicate sex-specific differences in selenium metabolism and selenoprotein expression (Schomburg & Schweizer, 2009). Nutrigenetics, which is the response of genetic variations on nutrients and the interaction thereof with disease states (Joost et al., 2007), may also be a reason why there were no associations found between selenium and GPx activity in the other individual groups of the present study.
Serum selenium and selenoprotein P status in adult Danes - 8-year followup
2009, Journal of Trace Elements in Medicine and BiologySelenium and glutathione peroxidases in blood of patients with different stages of chronic renal failure
2004, Journal of Trace Elements in Medicine and BiologySelenium status and its correlates in a British National Diet and Nutrition Survey: People aged 65 years and over
2002, Journal of Trace Elements in Medicine and BiologySelenium, glutathione peroxidases, and some other antioxidant parameters in blood of patients with chronic renal failure
2001, Journal of Trace Elements in Medicine and BiologyInteractions between essential and toxic elements in lead exposed children in Katowice, Poland
1998, Clinical Biochemistry
- ☆
The study was supported by grants from the Swedish Medical Research Council (Projects 3968 and 7010) and was also generously supported by the Malmö General Hospital. Additional support (to B.Å.) was provided by the Swedish Council for Forestry and Agricultural Research and the Påhlsson Foundation. W.H. was supported by the Medical Faculty, University of Lund, and E.M. by the Swedish Institute.
- 1
Dr. Marchaluk’s present address: Department of Biochemistry/Chemistry, University School of Medical Science, Bydgoszcz, Poland.