Predictive Ability of Serum Amino Acid Levels to Differentiate Fibromyalgia Patients from Healthy Subjects.

BACKGROUND: Fibromyalgia is a complex illness to diagnose and treat. OBJECTIVES: To evaluate a broad range of circulating free amino acid (AA) levels in fibromyalgia patients as well as the ability of the AAs to differentiate fibromyalgia patients from healthy subjects. DESIGN: We carried out a case-control study to evaluate AA levels in 62 patients with fibromyalgia and 78 healthy subjects. This study adheres to the STROBE guidelines. METHODS: AAs content was assayed by HPLC in serum samples. The predictive value of AA levels in fibromyalgia was determined by receiver operating characteristic (ROC) curve and forward binary logistic regression analyses. RESULTS: Fibromyalgia patients showed higher serum levels of aspartic acid, glutamic acid, aminoadipic acid, asparagine, histidine, 3-methyl-histidine, 5-methyl-histidine, glycine, threonine, taurine, tyrosine, valine, methionine, isoleucine, phenylalanine, leucine, ornithine, lysine, branched chain AAs (BCAAs), large neutral AAs, essential AAs (EAAs), non-essential AAs (NEAAs), basic AAs, EAAs/NEAAs ratio, phenylalanine/tyrosine ratio, and global arginine bioavailability ratio than the controls. Serum alanine levels were lower in patients than in controls. According to ROC analysis, most of these AAs may be good markers for differentiating individuals with fibromyalgia from healthy subjects. Results of logistic regression showed that the combination of glutamic acid, histidine, and alanine had the greatest predictive ability to diagnose fibromyalgia. CONCLUSIONS: Our results show an imbalance in serum levels of most AAs in patients with fibromyalgia, which suggest a metabolic disturbance. The determination of serum levels of these AAs may aid in the diagnosis of fibromyalgia, in combination with clinical data of the patient.

Calcitonin Gene-Related Peptide, Vascular Endothelial Growth Factor, and Clinical Manifestations in Women With Fibromyalgia.

BACKGROUND: Fibromyalgia is a complex illness to diagnose and treat, which significantly impairs patients' quality of life. OBJECTIVES: The study aims were to compare levels of calcitonin gene-related peptide and vascular endothelial growth factor between patients with fibromyalgia and healthy controls and to examine their relationship with the main clinical manifestations of fibromyalgia. METHODS: This case-control study included 42 women diagnosed with fibromyalgia and 22 healthy women. Serum calcitonin gene-related peptide and vascular endothelial growth factor levels were spectrophotometrically analyzed by enzyme-linked immunosorbent assay. Clinical manifestations were assessed by means of self-administered questionnaires, including functional capacity in daily living activities, musculoskeletal pain, fatigue, anxiety, and sleep quality. The predictive value of these parameters in fibromyalgia was determined by receiver operating characteristic curve analysis. RESULTS: Serum calcitonin gene-related peptide levels significantly increased in the fibromyalgia group in comparison to the control group. However, there were no significant differences in vascular endothelial growth factor levels between patients and controls. No significant correlations were found between calcitonin gene-related peptide and vascular endothelial growth factor and the symptoms analyzed. DISCUSSION: Serum calcitonin gene-related peptide levels were dysregulated in women with fibromyalgia and may be a reliable parameter to help diagnose this complex syndrome.