(Rac)-Indoximod (1-Methyl-DL-tryptophan) is a potent inhibitor of indoleamine 2,3-dioxygenase (IDO). Combined treatment with IFN-γ and (Rac)-Indoximod significantly suppresses the activity of α-SMA-expressing human cardiac myofibroblasts (hCMs) and promotes apoptosis by up-regulating the genes IRF-1, Fas, and FasL. Moreover, this co-treatment effectively improves cardiac fibrosis[1].

(Rac)-Indoximod (1-Methyl-DL-tryptophan; 0.5 mM; 3 days) inhibits tryptophan depletion, thereby partially reversing the growth-inhibitory activity of IFN-γ, but eventually induces cell death irrespective of tryptophan depletion [1]. Cell Viability Assay [1] Cell Line: Human cardiac myofibroblasts (hCMs) Concentration: 0.5 mM Incubation Time: 3 days Result: Growth retardation by IFN-γ was partially reversed on day 2, but cell viability was further reduced on day 3.