title: Selenium levels and Glutathione peroxidase activity in the plasma of patients with type II diabetes mellitus.
abstract: Selenium, an essential trace element, is involved in the complex system of defense against oxidative stress through selenium-dependent glutathione peroxidases (GPx) and other selenoproteins. Because of its antioxidant properties, selenium or its selenospecies at appropriate levels could hinder oxidative stress and so development of diabetes. In this vein, quantitative speciation of selenium in human plasma samples from healthy and diabetic patients (controlled and non-controlled) was carried out by affinity chromatography (AF) coupled on-line to inductively coupled plasma mass spectrometry (ICP-MS) and isotope dilution analysis (IDA). Similarly, it is well known that patients with diabetes who exhibit poor control of blood glucose show a decreased total antioxidant activity. Thus, we evaluated the enzymatic activity of GPx in diabetic and healthy individuals, using the Paglia and Valentine enzymatic method, observing a significant difference (p<0.05) between the three groups of assayed patients (healthy (n=24): 0.61±0.11U/ml, controlled diabetic (n=38): 0.40±0.12U/ml and non-controlled diabetic patients (n=40): 0.32±0.09U/ml). Our results show that hyperglycemia induces oxidative stress in diabetic patients compared with healthy controls. What is more, glycation of GPx experiments demonstrated that it is the degree of glycation of the selenoenzyme (another species of the Se protein) what actually modulates its eventual activity against ROS in type II diabetes mellitus patients.
authors.affiliation: Department of Physical and Analytical Chemistry, Faculty of Chemistry, University of Oviedo, Spain.
authors.forename: Raquel
authors.initials: R
authors.lastname: González de Vega
authors.affiliation: Department of Physical and Analytical Chemistry, Faculty of Chemistry, University of Oviedo, Spain. Electronic address: marisafs@uniovi.es.
authors.forename: María Luisa
authors.initials: ML
authors.lastname: Fernández-Sánchez
authors.affiliation: Management area of clinical laboratory medicine, Hospital Universitario Central de Aturias (HUCA), Oviedo, Spain.
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Fernández
authors.affiliation: Management area of clinical laboratory medicine, Hospital Universitario Central de Aturias (HUCA), Oviedo, Spain.
authors.forename: Francisco Vicente
authors.initials: FV
authors.lastname: Álvarez Menéndez
authors.affiliation: Department of Physical and Analytical Chemistry, Faculty of Chemistry, University of Oviedo, Spain. Electronic address: asm@uniovi.es.
authors.forename: Alfredo
authors.initials: A
authors.lastname: Sanz-Medel
mesh_terms: D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000201:enzymology*; D005979:Glutathione Peroxidase / Q000097:blood*; D006801:Humans; D012643:Selenium / Q000097:blood*
chemical_list: D005979:Glutathione Peroxidase; D012643:Selenium
keywords: Enzymatic activity; Glutathione peroxidase; ICP-MS; Oxidative strees; Speciation