SPX and metabolic syndrome: In human subjects, notable changes in SPX expression/serum level can be associated with pathological conditions/diseases, e.g., in type I/II (7, 26) or gestational diabetes (27), childhood (28, 29) and adult obesity (30), metabolic syndrome (31), cardiovascular disease (32), and anorexia nervosa/other psychiatric disorders (33, 34), which have aroused the interest of using SPX as a new target for drug design with clinical implications (22, 35).