Nolin and colleagues highlighted a lower expression of CYP in animal models of CKD (Nolin et al., 2008), while an ex vivo study carried out on rat hepatocytes showed that serum from patients with ESKD decreased the expression and activity of CYP1A, CYP2C, CYP2D, CYP3A and CYP4A, all of which are involved in the metabolization of xenobiotics (Michaud et al., 2005). Here, PPIG is linked to chronic kidney disease.