Background/Purpose: MicroRNAs (miRNAs) are small non-coding RNAs which are regulating physiologic and pathological processes. In numerous diseases specific miRNA signatures have been identified and can potentially serve as biomarkers. In psoriatic arthritis (PsA) no specific biomarker is available so far. As previously shown, inflammation of peripheral joints in patients with psoriasis can be identified using MRI technique despite no clinical evidence for psoriatic arthritis. Therefore, specific biomarkers to capture these patients at an early time point is of clinical interest. The aim of this pilot study was to identify specific circulating miRNA signatures in patients with psoriasis and psoriatic arthritis and to investigate potential biomarkers for inflammatory involvement of joints.

Methods: 16 patients with (PsA) fulfilling CASPAR criteria and 16 patients with psoriasis (PsO) without any current or past clinical symptom of arthritis or enthesitis received high field MRI of the hand, demographic and clinical data including disease duration, activity scoring as well as demographic data were collected. MRI scans were scored according to PsAMRIS method. 187 miRNAs were quantified in serum of PsA and PsO patients and 16 age- and sex-matched controls (CO) using RT-qPCR (TAmiRNA Vienna).

Results: PsA patients, PsO patients and CO had a comparable age (median (IQR), years, 48.5 (13.0) vs 53.0 (10.0) vs 48.0 (15.0), p=0.547). In all 3 cohorts 50% were females. BMI was higher, but not significantly above the upper normal range in PsA and PsO patients compared to CO(p=0.177). The median (IQR) disease duration of PsA patients was 2.5 (10) years. Duration of skin disease was 14.0 (31) years in PsA patients vs. 12.0 (14) years in PsO patients. 60% of PsO patients reported unspecific arthralgias without clinical signs of arthritis. In PsA Minimal Disease Activity (MDA) was present in 46.7% of patients. Psoriasis Area and Severity Index (PASI) was 0 (0.1) in PsA vs. 1.7 (5.3) in PsO patients. In MRI osteitis was found in 18.8% of PsA patients vs. 12.5% of PsO patients. Synovitis was present in 37.5% of PsA patients and in 43.8% of PsO patients. 1 patient of each group showed periarticular inflammation and tenosynovitis was only detected in PsA patients (25%). In the first analysis significant differences in miRNA profiles of patients with PsA, PsO and controls have been revealed. We were able to identify 51 miRNAs in the PsO and 64 miRNAs in the PsA group significantly down or upregulated (BH-adjusted p< 0.05) compared to healthy CO. Between these signatures, an overlap of 33 miRNAs, which were significantly changed in PsA and PsO compared to CO was detected (adjusted p< 0.05), while 18 (PsO) and 31 (PsA) miRNAs were specific to each group.

Conclusion: The results of miRNA analysis in this pilot study in patients with psoriasis and psoriatic arthritis suggest that serum microRNA levels are not identical between PsO and PsA compared to CO, and that miRNAs could serve as biomarkers to detect a joint involvement in psoriasis in the future.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/identification-of-circulating-microrna-signatures-in-patients-with-psoriasis-and-psoriatic-arthritis-to-develop-novel-strategies-for-early-diagnosis-of-a-bone-and-joint-involvement/