A2M and diabetes mellitus: Treatment with anti-proNGF by IV injection in diabetic mice normalized the increased levels of proNGF protein (0.876 ± 0.19 in treated mice compared to 1.96 ± 0.29 in control diabetic mice, p<0.01, n = 3) (Fig 4B) and the levels of α2M protein (1.16 ± 0.07 compared to 1.48 ± 0.05 in control diabetic mice, p<0.05, n = 3) (Fig 4D) in the retina at 6 weeks after the induction of diabetes (Fig 4A).