Figure 14.

Retinal pigment epithelium (RPE) cells expressed ionized calcium-binding adaptor molecule 1 (Iba-1)⁺ and increased numbers of lipofuscin-like granules in type 2 diabetes (T2D). Retinal sections from midperipheral region of rhesus nonhuman primates (NHPs). A, C, E, and G: Controls. B, D, F, H, and J: T2D. A and B: Stained with Iba-1 (red) and DAPI (blue). C and D: Represent adjacent sections of A and B and were stained only with DAPI (blue). Images show autofluorescent granules (red channel). E and F: Stained with Iba-1 (red) and DAPI (blue). Images show autofluorescent granules (green channel). G and H: Same images as E and F, but only with the green filter and DAPI. I: Increase in the relative thickness of the lipofuscin layer in the Western diet–fed animals compared with chow-fed controls. J: Same image as F but only showing Iba-1 and DAPI. Data are shown using adjacent sections and the same images with different combinations of filters intended to show the autofluorescence granules and Iba-1⁺ labeling more clearly. Images suggest that RPE cells become Iba-1⁺ and contain more lipofuscin-like granules in the T2D nonhuman primate. To quantitate the change of lipofuscin-like granules, the thickness of lipofuscin-like granules in the RPE cells of control and T2D NHP were compared. I: The increased amount both in extent and density of lipofuscin-like granules in RPE of the T2D NHPs comparing with control. ∗P < 0.05. Scale bars = 20 μm (A–H and J).