ENPP2 and chronic kidney disease: Observed in our studies higher LPA levels in the plasma of CKD patients, with a simultaneous decrease in LPC levels and a lack of correlation between these two parameters, may indicate a significant contribution of other than LPC substrates or other than ATX enzymes in plasma LPA synthesis, but they can also be associated with changes in the activity of the LPA-degrading enzymes or its extravascular origin.