Serum adipokine levels and associations with patient-reported fatigue in systemic lupus erythematosus.

Physical activity ameliorates fatigue in systemic lupus erythematosus (SLE) patients by an unknown mechanism. Adipokines, which are influenced by adiposity and physical activity, may be associated with patient-reported fatigue. We describe cross-sectional associations between adipokines and fatigue, physical activity, and SLE disease activity. We measured adipokines, self-reported fatigue, and objective physical activity in 129 SLE patients. Fatigue was assessed with the Fatigue Severity Scale (FSS) and Patient Reported Outcomes Measurement Information System® (PROMIS®) Fatigue score. Disease activity was measured with the Safety of Estrogens in Systemic Lupus Erythematosus National Assessment-Systemic Lupus Erythematosus Disease Activity Index (SELENA-SLEDAI). Participants wore an accelerometer for 7 days to measure physical activity. Leptin, adiponectin, and resistin were measured in stored serum with a Luminex bead-based assay. Multivariable regression models assessed relationships between fatigue and adipokines, and Spearman correlation coefficients summarized associations between adipokines, physical activity, and SELENA-SLEDAI. Median adipokine levels were: leptin 30.5 ng/ml (Interquartile Range 14.0, 56.6), adiponectin 11.6 µg/ml (7.2, 16.8) and resistin 1.4 ng/ml (1.0, 2.2). Associations between adipokines and FSS or PROMIS fatigue were not significant. Body mass index (BMI) ≥ 30 kg/m2 was associated with FSS and PROMIS fatigue in regression analyses (p < 0.05). Weak correlations between leptin, adiponectin, leptin/adiponectin (L/A) ratio, and physical activity and between adiponectin and SELENA-SLEDAI score were not significant after adjusting for BMI. Adipokines were not associated with fatigue in SLE. Adipokines were correlated with physical activity (leptin, adiponectin, L/A ratio) and SLE disease activity (adiponectin), but most of these associations were explained by BMI.

Candidate Biomarkers for Fatigue in Systemic Lupus Erythematosus: A Critical Review.

Fatigue impacts 80-90% of patients with systemic lupus erythematosus (SLE), and an incomplete understanding of fatigue mechanisms limits effective treatment. Disease activity indices and laboratory markers inconsistently correlate with fatigue severity in SLE populations. Identification of fatigue biomarkers has important implications for understanding pathogenesis and defining novel therapeutic targets, but a paucity of evidence exists for fatigue biomarkers in SLE. The evidence for adipokines, reduced glutathione, iron deficiency, and vitamin D as potential biomarkers for SLE-related fatigue are reviewed. To address gaps in the SLE literature, the experience of each fatigue biomarker in other diseases is examined. Finally, biomarker associations with SLE pathogenesis and disease activity are discussed, as further rationale for investigation among SLE patients.

Alpha-chlorofatty Acid and coronary artery or aorta calcium scores in women with systemic lupus erythematosus. A pilot study.

OBJECTIVE: Alpha-chlorofatty acid (α-ClFA) is one product of myeloperoxidase activity in vivo during atherogenesis and may be a biomarker for cardiovascular disease (CVD). We investigated if serum α-ClFA is associated with subclinical CVD as measured by coronary artery and aorta calcium scores (CAC and AC, respectively) in women with and without systemic lupus erythematosus (SLE). METHODS: This pilot project analyzed baseline data from 173 women with SLE and 186 women without SLE participating in a 5-year longitudinal investigation of the Study of Lupus Vascular and Bone Long-term Endpoints (SOLVABLE). Data collection included demographic information, CVD and SLE risk factors, and laboratory assessments. Alpha-ClFA was measured in stored serum by liquid chromatography-mass spectrometry. CAC and AC were measured by computed tomography. Outcome measures were CAC and AC present (CAC > 0 or AC > 0) versus absent (CAC = 0 or AC = 0). Associations between risk factors and CAC or AC were tested with descriptive statistics and multivariate analyses. RESULTS: Women with SLE had higher α-ClFA levels than women without SLE (42.0 fmol/25 µl ± 37.3 vs 34.5 fmol/25 µl ± 21.9; p = 0.020). In analyses including individual CVD risk factors, having SLE was independently associated with the presence of CAC (OR 3.42, 95% CI 1.72 to 6.78) but not AC. Alpha-ClFA was not associated with the presence of CAC or AC in patients with SLE. CONCLUSION: SLE, but not serum α-ClFA, was associated with the presence of CAC in this pilot project.