MBTPS1 and metabolic syndrome: Interestingly, it is worth mentioning that although S1P and SPC are both constituents of HDL [11,14,50], the significant decrease in HDL levels observed in MetS patients (Table 1) inversely correlated with plasma SPC levels (Table 2) but showed no correlation with plasma S1P levels (r = 0.359, p = 0.101).