ENPP2 and serum lipopolysaccharide activity: In order to study whether ATX is involved in the pathogenesis of mouse endotoxemia, the mice were injected intraperitoneally with LPS (from Escherichia coli dissolved in normal saline), an endotoxin present in the outer membrane of Gram-negative bacteria that induces an acute phase inflammatory response mimicking several of the initial clinical features of sepsis [18].