Furthermore, NNMT knockout mice that developed renal fibrosis showed a decrease in renal NNMT expression and NAD+ salvage pathway metabolites such as NAM, NMN, and NAD+, as well as an increase in degradation products of NAM such as MNA, N-Me-2PY, and N-Me-4PY. This evidence concerns the gene NNMT and renal fibrosis.