Background: The role of expression level of long noncoding RNA (lncRNA) taurine upregulated gene 1 (TUG1) as a risk of ankylosing spondylitis (AS) development is unclear. Aim: The aim of the current study is to investigate LncRNA TUG1 expression level in relation to AS and to the degree of disability and quality of life which has not been adequately studied.
Patients and Methods: In the present study, 50 Patients of AS and 50 healthy controls of matched age and gender were included. Patients were categorized into two groups based on Bath AS disease activity index (BASDAI): active AS patients and inactive AS cases. For AS patients, disease duration, clinical assessment, Quality of life was assessed using AS quality-of life-questionnaire (ASQoL). Mobility and functional limitations were assessed by Bath AS metrology index (BASMI) and Bath AS functional index scores (BASFI). Results: Structural damage was assessed using modified stroke ankylosing spondylitis spinal score (MSASSS). Laboratory investigations were done including: HLA-B27, ESR and CRP, Vitamin D levels by enzyme immunoassay method and measurement of LncRNA TUG1 by quantitative real time PCR (qRT-PCR). There was upregulation of LncRNA TUG1 in AS patients than control (p <0.001), at cutoff >6.2. TUG1 has a sensitivity of 88% and specificity of 84%. Active AS patients have significant higher level of LncRNA TUG1 than inactive AS (p <0.001) with a sensitivity of 84% and a specificity of 88%. Moreover, TUG1 could discriminate AS with structural damage from those without structural damage (p= 0.008). LncRNA TUG1 was positively correlated with CRP, BASDAI, VAS, BASDAI, BASMI, BASFI and MSASSS (p <0.001) and was not correlated with disease duration, ESR, Vit D or HLA-B27 (p >0.05).
Conclusion: These results indicated that for the first time, upregulation of LncRNA TUG1 increased the risk of AS and was associated with increased disease activity, structural damage, disability and poor quality of life.