POS0893 NON-INVASIVE CUTANEOUS ASSESSMENT OF SYSTEMIC SCLEROSIS- THE NEW OUTLOOKS
Authors: P. S. Wong, D. Kurzeja, B. Ahmed Abdi, R. Stratton
Journal: Annals of the Rheumatic Diseases (2021)

Background: Systemic sclerosis (SSc) is a rare connective tissue disease with abnormalities in vasculopathy, immune dysregulation and fibrosis resulting in skin and internal organ damages. Severity of skin involvement is known to correlate with organ-related mortality in particular pulmonary involvement. Variables skin assessment tools are available, modified Rodnan Skin Score (mRSS) is currently best validated and used widely. The immediate action of finding an ideal, clinically convenient objective methods is crucial to better clinicians‘ care for SSc patents. Objectives: Explore the potential of commercially available handheld, non-invasive devices for SSc skin analysis. Methods: 1.Measure skin surface Adenosine Triphosphate (ATP) level with handheld ATP bioluminator (SystemSURE Plus, Hygiena) over the forearm of SSc(n= 51) and controls (n=50) 60seconds after sterilization to eliminate extrinsic factors. The bioluminometer expresses ATP test results in Relative Light Units (RLU) that is directly proportional to the amount of ATP on the test sample (Unit conversion: 1RLU = 1fM). 2.In-vivo Raman Spectra measurement of SSc skin comparing with matched healthy controls on proximal phalangeal, area between 2 nd and 3 rd metacarpal and forearm. Our measurments include laser power of 250mw, excitation length of 785nm and spectral range from 500 to 2800cm -1 . Measurements were analysed with patients’ phenotypes and clinical characteristics. Results: Flow cytometry showed increase expression of P2X7 (purinergic) receptor and CD206 in M2-Macrophage in SSc compare to controls [(724.4 vs 472.9, 776.1 vs 632.2)]. CD206 expression positively correlated with P2X7 levels (p&lt;0.001, r2=0.76) and mRSS (p&lt;0.05, r2=0.26). In real life scenario, measurement of purinergic metabolites is laboratorial tedious. ATP bioluminator measurement reviewed significant higher skin surface ATP in SSc than controls (188fM ± 53 [95% CI = 84, 300] vs 44fM ± 6 [95% CI = 33, 56], p&lt; 0.003). And the intensity is negatively correlate with duration of disease in SSc (r = - 0.25, p = 0.096). We obtain Raman spectra in SSc patient and control. Our study both groups have similar Raman curve when Raman Spectrometry were performed on skin surfaces. However, the relative intensity of each peaks of the curve were overtly flatter in SSc. This finding were similar for both Limited and Diffuse SSc in gross review of the graph representative. In addition to that, our analysis reviewed a peak at Raman shift of 2410 cm -1 that is characteristically present in forearm of a SSc but not in controls (Figure 1). Its significant yet to be determined. Conclusion: Both ATP bioluminator and Raman Spectrometry is widely available commercially which are widely used in industrial, agriculture and cosmetology and dermatology in particular for Raman Spectrometry. It is commonly for assessing physically property of skin, determine drug administration and diagnosis of variable skin condition in particular cancer diagnosis. The advantages of these tools in SSc skin analysis include: 1.Non-invasive nature of skin analysis (compares to skin biopsy), 2.Portable devices easily mobilized in clinic setting, 3.Advanced technology allows molecular analysis of skin hence able to objectively classify grades of skin inflammation and determine drug efficacy 4.Possible better accuracy compares to other methods (eg. Ultrasound) which are operators dependent, 5.Widely available Raman signal database of different types of chemical compounds and expertise made the collection and analysis of date convenient Our study has provide preliminary outlook and idea of utilizing commercially available devices on skin analysis in SSc. Further study in larger cohort are to be considered. References: [1]Burnstock G, Knight GE, Greig AV. Purinergic signaling in healthy and diseased skin. The Journal of investigative dermatology. 2012;132(3 Pt 1):526-46. [2]Franzen L, Windbergs M. Applications of Raman spectroscopy in skin research. Advanced Drug Delivery Reviews.Volume 89.2015. Pages 91-104. Disclosure of Interests: None declared