ENPP1 and chronic kidney disease: Moreover, the calcium content in the thoracic aorta correlated positively and significantly with Enpp1 and Enpp3 aortic mRNA gene expression in vehicle-treated CKD rats and, as such, can be seen as (1) a survival mechanism, increasing local PPi levels to target the present arterial calcifications, or perhaps (2) an adverse process, by depleting local ATP levels leading to less purinergic signaling.