Macrophage phenotype and renal fibrosis in obstructive nephropathy.

Macrophages have classically been recognized as key players that may promote renal fibrosis. However, several recent studies have suggested a beneficial anti-fibrotic role of infiltrating macrophages that acts to preserve renal architecture in the progressive renal scarring associated with obstructive nephropathy. Furthermore, recent investigations indicate a role for macrophages in both inflammation and repair during disease processes and this has superseded the classical injurious view of macrophages. As a result, the exact role of interstitial macrophages upon various facets of renal fibrosis is an important challenge that needs to be addressed. In this article, we discuss the possible beneficial anti-fibrotic role of infiltrating macrophages in obstructive nephropathy and discuss the potential mechanisms that may regulate the effect of macrophages upon renal interstitial fibrosis.