Angiotensin II: A Regulator of Inflammation during Renal Disease?

It has been recently recognized that besides its vasoactive actions Angiotensin II (Ang II) exerts various immunomodulatory effects that may contribute to renal injury and to the progression of renal disease. Consistent with this concept, Ang II facilitates macrophage recruitment into the kidney either directly or through the upregulation of different chemotactic molecules such as RANTES (Regulated on Activation Normal T Expressed and Secreted), monocyte chemoattractant protein-1 (MCP-1) and osteopontin. Infiltrating macrophages not only produce a number of cytokines, growth factors and proinflammatory mediators, but also synthesize Ang II intacellularly which increases tissue levels of the hormone within the kidney. Finally, specific binding sites for Ang II have been demonstrated on macrophages and increasing evidence indicates that Ang II directly modulates many of the cellular functions of these cells during the course of renal disease. Together, these data suggest that Ang II plays an important role in modulating inflammatory responses in the kidney.