The C105F mutation causes myofibroblast proliferation, matrix deposition, and chronic renal failure with aging. A: Plasma creatinine levels measured by liquid chromatography–mass spectrometry. B, C, and F: Masson trichrome staining (B and C) and corresponding percentage area staining (F). D and E: α-Smooth muscle actin immunohistochemistry. n = 10 mice per group (A). ∗P < 0.05, ∗∗P < 0.01 versus wt 9 mo. Scale bars = 100 μm (B, C, D, and E). Mut, mutant; WT, wild type.