A recent paper by Cerdá-Olmedo, G. et al. unravels the miRNA signature in fibromyalgia (FM). Diagnosis of FM, a chronic musculoskeletal pain syndrome characterised by generalized body pain, hyperalgesia and other functional and emotional comorbidities, is a challenging process hindered by symptom heterogeneity and clinical overlap with other disorders. No objective diagnostic method exists at present.
This study aimed at identifying changes in miRNA expression profiles (miRNome) of FM patients for the development of a quantitative diagnostic method of FM. In addition, knowledge of FM patient miRNomes would lead to a deeper understanding of the etiology and/or symptom severity of this complex disease.
A broad profiling was first performed using Toray’s technology. miRNAs found were validated by qPCR in a later step. The profiling of FM patients PBMCs showed a marked downregulation of hsa-miR223-3p, hsa-miR451a, hsa-miR338-3p, hsa-miR143-3p, hsa-miR145-5p and hsa-miR-21-5p (4-fold or more).
Globally, 20% of the miRNAs analyzed (233/1212) showed downregulation of at least 2-fold in patients. This might indicate a general de-regulation of the miRNA synthetic pathway in FM. No significant correlations between miRNA inhibition and FM cardinal symptoms could be identified. However, the patient with the lowest score for mental fatigue coincided with the mildest inhibition in four of the five miRNAs associated with the FM-group.
Therefore, the authors propose a signature of five strikingly downregulated miRNAs (hsa-miR223-3p, hsa-miR451a, hsa-miR338-3p, hsa-miR143-3p and hsa-miR145-5p) to be used as biomarkers of FM. Validation in larger study groups would be required before the results can be transferred to the clinic, as the authors indicate.
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