Bmp6 protein levels in age-related macular degeneration. A: Bright-field photomicrographs of postmortem human retinas showed weaker Bmp6 immunoreactivity (black labeling) within RPE in early AMD (upper right, arrows), relative to normal human RPE (upper left). In advanced AMD, relative to normal, the signal was stronger throughout the neurosensory retina (lower right); the asterisk indicates subretinal fibrous scar. The RPE is absent, as it had degenerated. Nuclei, visualized with DAPI stain and simultaneous fluorescence imaging, appear white. B: Western analysis from four normal and four AMD neurosensory retinas showed significantly higher Bmp6 precursor protein levels (57 kDa) in AMD eyes relative to normal controls. C: Densitometry confirmed the Western blot analysis. D: A model for the relationships among iron, oxidative stress, and Bmp6. F, female; M, male; MW, molecular weight ladder. *P < 0.05. Scale bars: 50 μm (A, upper row); 100 μm (A, lower row).