title: Plasma glutathione peroxidase (GSH-Px) concentration is elevated in rheumatoid arthritis: a case-control study.
abstract: Plasma glutathione peroxidase (GSH-Px) by enzyme-linked immunosorbent assay (ELISA) offers a complimentary measurement approach to traditional GSH-Px activity methods. The aim was to investigate whether GSH-Px measured by ELISA in rheumatoid arthritis patients was elevated compared to controls. This was a case-control study with rheumatoid arthritis patients recruited from private practice and gender and age-matched controls randomly selected from the electoral role. GSH-Px concentration was measured by ELISA. Plasma malondialdehyde was used as a measure of oxidative stress, and antioxidant capacity was measured based on reduction of Cu(++) to Cu(+) by antioxidants in the sample. Disease severity was measured using the Health Assessment Questionnaire-Disability Index (HAQ-DI) and C-reactive protein was measured using an immunoturbidometric method. A total of 74 patients were recruited, consisting of 35 rheumatoid arthritis cases and 39 healthy controls. There were no differences between rheumatoid arthritis cases and controls for oxidative stress and antioxidant capacity; however, GSH-Px concentration was markedly elevated in the rheumatoid arthritis sufferers (85.9 ± 147.7 versus 17.3 ± 13.0 mg/L, respectively; mean ± SD; p < 0.01). GSH-Px levels were not associated with severity measured by the HAQ-DI or C-reactive protein. Patients with rheumatoid arthritis demonstrated increased GSH-Px consistent with an adaptive upregulation of GSH-Px to protect against oxidative stress.
authors.affiliation: School of Pharmacy, University of Tasmania, Private Bag 26, GPO Box 252, Hobart, Tasmania 7001, Australia. glenn.jacobson@utas.edu.au
authors.forename: Glenn A
authors.initials: GA
authors.lastname: Jacobson
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Ives
authors.forename: Christian
authors.initials: C
authors.lastname: Narkowicz
authors.forename: Graeme
authors.initials: G
authors.lastname: Jones
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000975:Antioxidants / Q000378:metabolism; D001172:Arthritis, Rheumatoid / Q000097:blood*; D002097:C-Reactive Protein / Q000096:biosynthesis; D016022:Case-Control Studies; D004185:Disability Evaluation; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D005786:Gene Expression Regulation; D005979:Glutathione Peroxidase / Q000097:blood*; D006801:Humans; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D008875:Middle Aged; D018384:Oxidative Stress; D015854:Up-Regulation
chemical_list: D000975:Antioxidants; D008315:Malondialdehyde; D002097:C-Reactive Protein; D005979:Glutathione Peroxidase