MALDI-TOF and SELDI-TOF analysis: "tandem" techniques to identify potential biomarker in fibromyalgia. [MALDI-TOF e SELDI-TOF: due tecniche “tandem” per l’individuazione di potenziali biomarker nella fibromialgia]

Objective: Fibromyalgia (FM) is characterized by the presence of chronic widespread pain throughout the mus- culoskeletal system and diffuse tenderness. Unfortunately, no laboratory tests have been appropriately validated for FM and correlated with the subsets and activity. The aim of this study was to apply a proteomic technique in saliva of FM patients: the Surface Enhance Laser Desorption/Ionization Time-of-Flight (SELDI-TOF). Methods: For this study, 57 FM patients and 35 HC patients were enrolled. The proteomic analysis of saliva was carried out using SELDI-TOF. The analysis was performed using different chip arrays with different character- istics of binding. The statistical analysis was performed using cluster analysis and the difference between two groups was underlined using Student’s t-test. Results: Spectra analysis highlighted the presence of several peaks differently expressed in FM patients com- pared with controls. The preliminary results obtained by SELDI-TOF analysis were compared with those ob- tained in our previous study performed on whole saliva of FM patients by using electrophoresis. The m/z of two peaks, increased in FM patients, seem to overlap well with the molecular weight of calgranulin A and C and Rho GDP-dissociation inhibitor 2, which we had found up-regulated in our previous study. Conclusion: These preliminary results showed the possibility of identifying potential salivary biomarker through salivary proteomic analysis with MALDI-TOF and SELDI-TOF in FM patients. The peaks observed allow us to focus on some of the particular pathogenic aspects of FM, the oxidative stress which contradistinguishes this condition, the involvement of proteins related to the cytoskeletal arrangements, and central sensibilization.