THU0020 COMPARATIVE STUDY OF THE PHOSPHODIESTERASE TYPE 5 INHIBITOR SILDENAFIL AND THE PROSTACYCLIN ANALOGUE ILOPROST ON IP10 MODULATION IN SYSTEMIC SCLEROSIS

Background Systemic sclerosis (SSc) is an autoimmune disease ending in multiorgan fibrosis. Vascular damage, responsible for the vascular alteration and disruption, has been suggested to play a key role in disease maintenance and progression [1]. Recent data demonstrated that high serum levels of the interferon (IFN)-γ-induced protein 10 (IP-10) in SSc patients correlated with peripheral vascular injure and increased in association with nailfold capillaroscopic pattern worsening and digital ulcers presence [2, 3]. Between the vasoactive drugs used for SSc treatment, the prostacyclin analogue iloprost (I) and PDE-5 inhibitor sildenafil (S) seem to have high vasodilatatory and immunomodulatory actions [4-6]. Objectives To investigate and compare the ability of S and I to modulate: IP-10 circulating levels in SSc patients under different treatments; IP-10 release by human endothelial (Hfaec) cells subjected to Th1-related inflammatory stimuli. Methods Sera of 28 patients satisfying ACR/EULAR 2013 classification criteria for SSc were analyzed by ELISA. IFNγ+TNFα-induced activation of NFkB, STAT1, JNK, ERK1/2 and AKT in Hfaec after S or I was tested by Western blot. Results The treatment with S significantly reduced IP-10 serum levels vs. treatment with (DMARDS) and corticosteroids (CCs) (184.1±65.10 vs. 880.9±339.0 pg/ml and vs. 426.5±101.7, respectively, P<0.01); while no significant difference has been found vs. I (184.1±65.10 vs. 282.7±46.6 pg/ml). In Hfaec, S and I differently counteracted the IFN-γ/TNF-α-induced phosphorylation of JNKs (respectively 61.6.0±20.1% and 9.5±13.1% of phosphorylation vs. I+T-induced taken as 100%), STAT1 (respectively 49.2±15.8% and 93.4±1.2% of phosphorylation vs. I+T-induced taken as 100%), NFkB (respectively 72.6±8.3% and 92.2±3.3% of phosphorylation vs. I+T-induced taken as 100%), ERK1/2 (respectively 31.6±7.9% and 27.3±4.4% of phosphorylation vs. I+T-induced taken as 100%), and AKT (respectively 85.7±5.6% and 3.8±7.4% of phosphorylation vs. I+T-induced taken as 100%). Conclusion In vivo results show that S and I have more effect in targeting serum IP-10 in SSc patients than other therapeutic treatments. In vitro data show different inhibitory drug-induced effects onto paths underlying IP-10 production, depending on intracellular targets. S could be a potential pharmacological tool as effective as I to control IP-10 in blood or at endothelial cell level in SSc. References [1] Varga J, et al., 2007. [2] Antonelli A, et al., 2008. [3] Crescioli C, et al., 2018. [4] Scorza R, et al., 2001. [5] Higuchi T, et al., 2015. [6] Hassoun PM, et al. 2015. Disclosure of Interests clara crescioli: None declared, Valeria Riccieri: None declared, Katia Stefanantoni Consultant for: Only 1 scientific advice for Italfarmaco in 2016, clarissa corinaldesi: None declared, massimiliano vasile: None declared, francesco marampon: None declared, Guido Valesini: None declared, andrea lenzi: None declared, luigi di luigi: None declared, cristina antinozzi: None declared