1. Intervention with an erythropoietin-derived peptide protects against neuroglial and vascular degeneration during diabetic retinopathy.
- Author
-
McVicar CM, Hamilton R, Colhoun LM, Gardiner TA, Brines M, Cerami A, and Stitt AW
- Subjects
- Animals, Animals, Newborn, Apoptosis drug effects, Cytokines genetics, Cytokines metabolism, DNA Damage drug effects, Diabetic Retinopathy metabolism, Diabetic Retinopathy pathology, Gene Expression Regulation drug effects, Ischemia drug therapy, Ischemia metabolism, Ischemia pathology, Male, Mice, Mice, Inbred C57BL, Neuroglia pathology, Peptide Fragments adverse effects, Peptide Fragments chemistry, Protein Interaction Domains and Motifs, Random Allocation, Rats, Rats, Sprague-Dawley, Retina drug effects, Retina metabolism, Retina pathology, Retinal Vessels pathology, Diabetic Retinopathy drug therapy, Erythropoietin chemistry, Nerve Degeneration prevention & control, Neuroglia drug effects, Peptide Fragments therapeutic use, Retinal Degeneration prevention & control, Retinal Vessels drug effects
- Abstract
Objective: Erythropoietin (EPO) may be protective for early stage diabetic retinopathy, although there are concerns that it could exacerbate retinal angiogenesis and thrombosis. A peptide based on the EPO helix-B domain (helix B-surface peptide [pHBSP]) is nonerythrogenic but retains tissue-protective properties, and this study evaluates its therapeutic potential in diabetic retinopathy., Research Design and Methods: After 6 months of streptozotocin-induced diabetes, rats (n = 12) and age-matched nondiabetic controls (n = 12) were evenly split into pHBSP and scrambled peptide groups and injected daily (10 μg/kg per day) for 1 month. The retina was investigated for glial dysfunction, microglial activation, and neuronal DNA damage. The vasculature was dual stained with isolectin and collagen IV. Retinal cytokine expression was quantified using real-time RT-PCR. In parallel, oxygen-induced retinopathy (OIR) was used to evaluate the effects of pHBSP on retinal ischemia and neovascularization (1-30 μg/kg pHBSP or control peptide)., Results: pHBSP or scrambled peptide treatment did not alter hematocrit. In the diabetic retina, Müller glial expression of glial fibrillary acidic protein was increased when compared with nondiabetic controls, but pHBSP significantly reduced this stress-related response (P < 0.001). CD11b+ microglia and proinflammatory cytokines were elevated in diabetic retina responses, and some of these responses were attenuated by pHBSP (P < 0.01-0.001). pHBSP significantly reduced diabetes-linked DNA damage as determined by 8-hydroxydeoxyguanosine and transferase-mediated dUTP nick-end labeling positivity and also prevented acellular capillary formation (P < 0.05). In OIR, pHBSP had no effect on preretinal neovascularization at any dose., Conclusions: Treatment with an EPO-derived peptide after diabetes is fully established can significantly protect against neuroglial and vascular degenerative pathology without altering hematocrit or exacerbating neovascularization. These findings have therapeutic implications for disorders such as diabetic retinopathy.
- Published
- 2011
- Full Text
- View/download PDF