Figure 2.

Macrophages polarize toward a proinflammatory phenotype in kidney disease. Th1 cytokines and microbial signals such as lipopolysaccharide (LPS) promote macrophage polarization toward the proinflammatory M1 phenotype in kidney injury. M1 macrophages release proinflammatory cytokines leading to further kidney injury. Macrophages can be polarized toward the M2 phenotype; however, macrophages are plastic in nature and may move back and forth between proinflammatory and anti-inflammatory phenotype depending on external signals. Abbreviations: ACE-i, angiotensin-converting enzyme inhibitor; IFN-γ, interferon γ; TGF-β, transforming growth factor β; Th1, T-helper cell 1; TNF-a, tumor necrosis factor a; TZD, thiazolidinedione.