SPP1 and coronary artery disorder: As previously reported by other authors (Tousoulis et al., 2013; Wolak, 2014; Maniatis et al., 2019), circulating OPN levels were lower in controls compared to the CAD patients (57.76 ± 9.8 vs 68.37 ± 24.2 pg/ml, respectively, p = 0.04, Supplementary Figure S1).