Mechanisms that control increased production (e.g., IDO1, KMO, KAT, QPRT) and extracellular release of these molecules (e.g., kynurenine, kynurenic acid, NAMPT, quinolinate, NMN, NAM) may be therapeutic targets in CKD (Figs. 3 and 9). This evidence concerns the gene QPRT and chronic kidney disease.