The broken Krebs cycle in pro-inflammatory macrophages. Macrophage polarization towards a pro-inflammatory phenotype is associated with metabolic changes, such as remodelling of the Krebs cycle. This leads to accumulation of citrate, which serves as a precursor of FA and prostaglandin biosynthesis, and succinate, which prevents degradation of the HIF-1α. The Krebs cycle is replenished by an increased flux through the AASS. α-KG, α-ketoglutarate; OAA, oxaloacetate.