title: Selenium supplementation enhances low selenium levels and stimulates glutathione peroxidase activity in peripheral blood and distal colon mucosa in past and present carriers of colon adenomas.
abstract: Selenoproteins such as glutathione peroxidases (GPx), thioredoxin reductases (TrxR), and selenoprotein P (SePP) contain molecular selenium in form of selenocysteines within their active center. They are involved in the defense of reactive oxygen species, which otherwise may cause DNA damage and alterations of protein function. Selenium intake has been linked to colon carcinogenesis in epidemiological and interventional studies. In a double-blinded, placebo-controlled trial, we demonstrate that carriers of colon adenomas present with low basal serum levels of selenium and plasma glutathione peroxidase (pGPx) activity before treatment, but both parameters can be normalized by interventional selenium supplementation. GPx activity in colon mucosa was enhanced in the verum group, albeit this had only borderline significance. No change of activity was observed for mucosal TrxR activity on selenium supplementation. In summary, our results confirm the existence of low selenium levels in patients prone to colon adenomas and show that by selenium supplementation this can be normalized. If prospective trials confirm that selenium supplementation reduces colon cancer incidence rates, it may be concluded that selenium supplementation should be recommended for patients at risk.
authors.affiliation: Medizinische Poliklinik, Abteilung Molekulare Innere Medizin, Universitat Wurzburg, Germany.
authors.forename: Oliver H
authors.initials: OH
authors.lastname: Al-Taie
authors.forename: Jochen
authors.initials: J
authors.lastname: Seufert
authors.forename: Serhan
authors.initials: S
authors.lastname: Karvar
authors.forename: Christian
authors.initials: C
authors.lastname: Adolph
authors.forename: Hubert
authors.initials: H
authors.lastname: Mörk
authors.forename: Michael
authors.initials: M
authors.lastname: Scheurlen
authors.forename: Josef
authors.initials: J
authors.lastname: Köhrle
authors.forename: Franz
authors.initials: F
authors.lastname: Jakob
mesh_terms: D000236:Adenoma / Q000201:enzymology*; D003106:Colon / Q000201:enzymology*; D003110:Colonic Neoplasms / Q000201:enzymology* / Q000517:prevention & control; D019587:Dietary Supplements; D004311:Double-Blind Method; D005979:Glutathione Peroxidase / Q000097:blood*; D006801:Humans; D007413:Intestinal Mucosa / Q000201:enzymology; D010919:Placebos; D012643:Selenium / Q000008:administration & dosage* / Q000097:blood*; D018038:Sodium Selenite / Q000008:administration & dosage; D013880:Thioredoxin-Disulfide Reductase / Q000378:metabolism
chemical_list: D010919:Placebos; D005979:Glutathione Peroxidase; D013880:Thioredoxin-Disulfide Reductase; D012643:Selenium; D018038:Sodium Selenite