[Expression and clinical significance of plasma exosomal miR-34-5p and miR-142-3p in systemic sclerosis].

Objective: To detect the expression of plasma exosomal microRNA (miRNA) in systemic sclerosis (SSc), and to investigate its clinical significance.

Methods: A total of 20 patients who were initially diagnosed with SSc and did not receive medication in Department of Rheumatology and Immunology of Meizhou People' s Hospital from January 2020 to January 2022 were recruited, as well as 15 healthy individuals whose gender and age matched with those of the SSc patients. Plasma exosomes were isolated using ultracentrifugation method. The expression levels of exosomal miR-34-5p, miR-92-3p and miR-142-3p were detected by quantative real-time polymerase chain reaction (qRT-PCR). Correlations between the expression levels of exosomal miRNAs and clinical characteristic were analyzed by Spearman's rank correlation coefficient test.

Results: The mean age of 20 patients with SSc was (52.6±12.6) years, including 7 males and 13 females. Among the 20 SSc patients, 13 cases were diagnosed as limited cutaneous systemic sclerosis (lcSSc) and 7 cases were diagnosed as diffuse cutaneous systemic sclerosis (dcSSc) according to the extent of skin involvement. According to the findings of high resolution chest CT, 7 of 20 SSc patients were diagnosed with interstitial lung disease (ILD) and 13 SSc patients were diagnosed with non-ILD. The expression levels of exosomal miR-34-5p, miR-92-3p and miR-142-3p were significantly elevated in the SSc patients compared with those in the healthy controls group (=0.003, =0.000 1, and =0.016, respectively). Compared with the SSc patients without ILD, the expression levels of miR-34-5p and miR-142-3p were significantly lower in the SSc patients with ILD (=0.037 and =0.015, respectively). The expression levels of exosomal miR-34-5p and miR-142-3p showed negative correlation with ILD (=-0.48, =0.031 and =-0.55, =0.011, respectively), and arthritis (=-0.46, =0.040 and =-0.48, =0.032, respectively). The expression levels of exosomal miR-142-3p showed a negative correlation with erythrocyte sedimentation rate (ESR) (=-0.55, =0.012).

Conclusion: Plasma exosomal miR-34-5p, miR-92-3p and miR-142-3p were dysregulated in SSc. The dyregulation of exosomal miR-34-5p and miR-142-3p showed correlation with SSc associated ILD (SSc-ILD).