NAMPT and obesity due to melanocortin 4 receptor deficiency: Visfatin, also termed as nicotinamide phosphoribosyltransferase (NAMPT), is another adipokine whose expression level is up-regulated in obesity, similar to leptin.41,42 As reported previously, visfatin could promote the IL-6 expression and ECM degradation of NP cells by JNK/ERK/p38-MAPK signaling to contribute to IDD.43 The NLRP3 inflammasome exerted important functions in IDD, and visfatin was also found to activate NLRP3 inflammasome to facilitate ECM degradation of rat NP cells through the MAPK/NF-κB signaling.44