Evaluation of cytokines, oxidative stress markers and brain-derived neurotrophic factor in patients with fibromyalgia - A controlled cross-sectional study.

OBJECTIVES: Previous studies measuring serum levels of biomarkers of inflammation/oxidative stress and neurotrophins levels in fibromyalgia (FM) have rendered inconsistent results. In the present study, our aim was to explore the levels of interleukins, oxidative stress markers and brain-derived neurotrophic factor (BDNF) in patients with FM in relation to depression and severity of disease. METHODS: In a prospective controlled cross-sectional study, serum concentrations of IL-6, IL-8, IL-10, TNF-α, thiobarbituric acid reactive substances (TBARS), protein carbonyl and BDNF were measured in 69 FM patients and 61 healthy controls (all women). In the FM group, the Fibromyalgia Impact Questionnaire (FIQ), the Beck Depression Inventory (BDI) and the Hamilton Depression Rating Scale (HDRS) were applied. Mann Whitney's and Spearman correlation tests were used for statistical analysis. RESULTS: The FM patients demonstrated a significant impact of the disease on quality of life (FIQ 70.2±17.8) and most of them had depression at some level (82.6% and 87.0% as assessed by BDI and HDRS, respectively). Most biomarkers (IL-6, IL-8, TNF-α, TBARS and protein carbonyl) and BDNF did not differ significantly between patients and controls, but the IL-10 levels were higher in FM patients (adjusted p=0.041). Among FM patients, there was no correlation of HDRS, FIQ, and BDI scores with any biomarker tested here. CONCLUSION: We observed no significant differences in biomarkers between FM patients and controls, except for higher levels of IL-10 (an anti-inflammatory cytokine) in patients. The levels of biomarkers were not correlated with parameters of disease and depression severity.

High frequency of asymptomatic hyperparathyroidism in patients with fibromyalgia: random association or misdiagnosis?

Fibromyalgia (FM) and hyperparathyroidism may present similar symptoms (musculoskeletal pain, cognitive disorders, insomnia, depression and anxiety), causing diagnostic confusion. OBJECTIVES: To determine the frequency of asymptomatic hyperparathyroidism in a sample of patients with FM and to evaluate the association of laboratory abnormalities to clinical symptoms. METHODS: Cross-sectional study with 100 women with FM and 57 healthy women (comparison group). Parathyroid hormone (PTH), calcium and albumin levels were accessed, as well as symptoms in the FM group. RESULTS: In FM group, mean serum calcium (9.6±0.98mg/dL) and PTH (57.06±68.98pg/mL) values were considered normal, although PTH levels had been significantly higher than in the comparison group (37.12±19.02pg/mL; p=0.001). Hypercalcemic hyperparathyroidism was diagnosed in 6% of patients with FM, and 17% of these women exhibited only high levels of PTH, featuring a normocalcemic hyperparathyroidism, with higher frequencies than those expected for their age. There was no significant association between hyperparathyroidism and FM symptoms, except for epigastric pain, which was more frequent in the group of patients concomitantly with both diseases (p=0.012). CONCLUSIONS: A high frequency of hyperparathyroidism was noted in women with FM versus the general population. Normocalcemic hyperparathyroidism was also more frequent in patients with FM. Longitudinal studies with greater number of patients are needed to assess whether this is an association by chance only, if the increased serum levels of PTH are part of FM pathophysiology, or even if these would not be cases of FM, but of hyperparathyroidism.