Session Type: ACR Concurrent Abstract Session
Session Time: 2:30PM-4:00PM
Giant cell arteritis (GCA) is a systemic vasculitis of large- and medium-sized arteries, diagnosed either with a temporal artery biopsy (TAB) histology or by imaging techniques. MicroRNAs (miRNAs), the small non-coding RNAs, regulate gene expression post-transcriptionally and contribute to the pathogenesis of autoimmune diseases, including GCA (1). We aimed to explore whether miRNA expression in TABs of treatment-naïve GCA patients is deregulated and could separate TAB-positive GCA from TAB-negative or non-GCA patients.
Total RNA was isolated from TABs of 24 patients, suspected of having GCA at disease presentation. These patients comprised 3 groups: GCA patients with transmural artery inflammation (TAB-positive; n=12), GCA patients without inflammation (TAB-negative, n=6), and patients in whom GCA was finally refuted (non-GCA, n=6). Occlusion of lumen of temporal arteries in GCA patients was also recorded. The expression of selected miRNAs (based on literature search), including miR-155, -146-a, -146-b, -299, -17-3p, -181-b, -125-b and -29-b was measured with TaqMan qPCR using specific single TaqMan miRNA assays and normalization to the levels of the small nucleolar RNA (RNU48).
While confirming significantly higher median (IQR) of miR-155 expression in TAB-positive GCA patients (0.118 (0.096)) as compared to TAB-negative GCA patients (0.017 (0.051); p<0.01) and non-GCA patients (0.029 (0.083); p<0.05) (1), our study also shows significantly lower miR-17-3p expression in TAB-positive (0.002 (0.001)) vs. TAB-negative (0.003 (0.001); p<0.05) GCA patients. MiR-125-b expression was significantly up-regulated in TAB-positive (0.410 (0.358); p<0.05) and TAB-negative (0.910 (0.573); p<0.001) GCA patients as compared to non-GCA patients (0.029 (0.024)). There was no difference observed between the three groups of patients for miR-146-a, -146-b, -299, -181-b and -29-b. GCA patients with occlusion of lumen of temporal arteries had significantly higher expression of miR-155 (0.113 (0.102) vs 0.036 (0.09); p<0.05), -146-b (1.029 (0.1) vs 0.305 (0.574); p<0.01) and -299 (0.004 (0.006) vs 0.001 (0.002); p<0.01) as compared to patients without lumen occlusion.
Our study reports for the first time that miR-125-b could be useful as a biomarker for distinguishing non-GCA patients from TAB-negative GCA patients. MiR-125-b could potentially be involved in tissue remodelling, since it was found to regulate matrix metalloproteinases-2 and -9. This could aid, in the future, to identify patients with atypical GCA presentation, without signs of inflammation in TABs.
- Crocci S, et al. MicroRNA markers of inflammation and remodelling in temporal arteries from patients with giant cell arteritis. Ann Rheum Dis. 2016;75(8): 1527-33.
To cite this abstract in AMA style:Kuret T, Frank Bertoncelj M, Lakota K, Sodin Semrl S, Čučnik S, Tomšič M, Hočevar A. MiR-125-b Is a Promising Biomarker for Giant Cell Arteritis in Patients with Negative Temporal Artery Biopsy Examination [abstract]. Arthritis Rheumatol. 2018; 70 (suppl 10). https://acrabstracts.org/abstract/mir-125-b-is-a-promising-biomarker-for-giant-cell-arteritis-in-patients-with-negative-temporal-artery-biopsy-examination/. Accessed December 7, 2019.
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