gms | German Medical Science

Introduction: Selenium (Se) is an essential micronutrient and is identified as an important element for the antioxidant defense. Through its incorporation into selenoproteins, Se is involved in the regulation of oxidative stress, redox state and other important cellular processes, including those involved in innate and adaptive immune response reactions [1]. In addition, copper (Cu) and zinc (Zn) are integral functional components of many enzymes and transcriptional regulatory proteins affecting inflammatory responses [2]. Our aim was to investigate the micronutrient status of selenium and other trace elements in patients with axial spondyloarthritis (axSpA) and psoriatic arthritis (PsA).

Methods: The study included patients with the clinical diagnosis of axSpA or PsA from the prospective daily practice observational cohort (LORE). Serum samples from the biomaterial bank were collected and trace elements were measured using Total reflection X-ray fluorescence (TXRF). In addition, the Se transporter SELENOP and activity of glutathione peroxidase-3 (GPx3) were quantified.

Results: Eighty-four patients with axSpA (60 males, median age 43 years, range 20–74) and 76 patients with PsA (32 males, median age 53 years, range 22–76) were included. Serum Se was relatively low as compared to healthy adults [3], but no differences in the concentrations of serum Cu, Se or Zn were detected between axSpA and PsA. Significant positive correlations were observed between the three biomarkers of Se status (Se, SELENOP and GPx3). Spearman correlation analysis indicated that SELENOP and Zn correlate negatively with c-reactive protein (CRP) in patients with axSpA (r=-0.34, p=0.0013 and r=-0.33, p=0.0021 respectively), whereas Cu correlated positively (r=0.43, p<0.001) (Figure 1 [Fig. 1]). Similar results were found for inflammation measured by the erythrocyte sedimentation rate (ESR).

Conclusion: Se and Zn status are negatively associated with inflammatory burden in axSpA and PsA, whereas Cu shows a positive association. SELENOP proved as sensitive biomarker for objective inflammatory and should be further investigated during therapy with bDMARD with respect to alterations in inflammatory burden.