IDO1 and atherosclerosis: In vascular inflammation and atherosclerosis, IDO1 activity in bone marrow-derived macrophages was proposed to have adverse effects by inhibition of the anti-inflammatory cytokine IL-10 via kynurenic acid mediated activation of a cAMP-dependent pathway and inhibition of Erk1/2 phosphorylation (Metghalchi et al. 2015).