C3 and diabetes mellitus: Retinal tissues from diabetic donors with early DR changes showed a significant increase for the C3 gene (13.082 ± 4.24, **p = 0.008) compared to the control retina (without a history of diabetes and vascular changes), while it was insignificant for the CD11b (1.2 ± 0.32) and CFH (1.56 ± 0.49) genes (Figure 7D).