title: Oxidative stress due to Mycobacterium avium subspecies paratuberculosis (MAP) infection upregulates selenium-dependent GPx activity.
abstract: OBJECTIVE
  This study was designed to determine the relationship between Mycobacterium avium subspecies paratuberculosis (MAP) infection and selenium-dependent glutathione peroxidase (GPx) activity, in the blood of humans and cattle infected with MAP.
  
  
  METHODS
  MAP infection status and GPx activity were determined in sera from 42 cattle, a group of 27 patients with Crohn's disease and 27 of their healthy biological relatives, and a group of 66 subjects with various diseases other than Crohn's disease and 34 non-related healthy subjects.
  
  
  RESULTS
  GPx activity was significantly higher overall in the case of MAP infection in both humans and cattle. The mean value for GPx activity was 1.59 ± 0.65 units/ml in MAP positive cattle compared to 0.46907 ± 0.28 units/ml in healthy cattle sera, where a unit was defined as one mmol/minute (P < 0.01). The mean value of the GPx activity in MAP negative humans clinical sera was 0.42367 ± 0.229 units/ml compared to 0.80941 ± 0.521 in MAP positive sera in a study comparing Crohn's disease patients to their healthy relatives. The mean activity in MAP negative humans was 0.4702 ± 0.1299 compared to 0.6510 ± 00.1665 units/ml in positive samples in a randomized field study of 100 subjects.
  
  
  CONCLUSIONS
  This study demonstrated a strong correlation between MAP and the elevation of GPx activity. This was especially evident in Crohn's patients, which further supports the association of MAP and Crohn's disease. GPx activity may also be used to predict MAP infection status and to show that Crohn's disease patients who are infected with MAP have higher tendency to develop oxidative stress than Crohn's disease patients who are negative for the bacteria.
authors.affiliation: Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, 4110 Libra Drive, Orlando, FL USA.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Qasem
authors.affiliation: Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, 4110 Libra Drive, Orlando, FL USA.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Abdel-Aty
authors.affiliation: Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, 4110 Libra Drive, Orlando, FL USA.
authors.forename: Huda
authors.initials: H
authors.lastname: Abu-Suwa
authors.affiliation: Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, 4110 Libra Drive, Orlando, FL USA.
authors.forename: Saleh A
authors.initials: SA
authors.lastname: Naser
keywords: Crohn’s disease; Glutathione peroxidase; MAP; Mycobacterium paratuberculosis; Oxidative stress; Type I diabetes