Cellular and Molecular Neurobiology

, Volume 28, Issue 2, pp 317–329 | Cite as

Up-regulated Endogenous Erythropoietin/Erythropoietin Receptor System and Exogenous Erythropoietin Rescue Retinal Ganglion Cells after Chronic Ocular Hypertension

  • Qing-Ling Fu
  • Wutian Wu
  • Hua Wang
  • Xin Li
  • Vincent W. H. Lee
  • Kwok-Fai SoEmail author
Original Paper



Recent studies have showed that erythropoietin (EPO) is a neuroprotectant for central nerve system neurons in addition to being a hematopoietic cytokine in response to hypoxia. In this study, we investigate the role of the EPO/EPO receptor (EPOR) system in the rat retina after ocular hypertension injury that mimics glaucoma.


Elevated intraocular pressure was induced by laser coagulation of the episcleral and limbal veins. Expression of EPO and EPOR in the normal and glaucomous retinas was investigated by immunohistochemistry and Western blot. To examine the effects of endogenous EPO on the survival of retinal ganglion cells (RGCs) subjected to hypertensive injury, soluble EPOR was directly injected into the vitreous body. Recombinant human EPO was both intravitreally and systemically administrated to study the effect of exogenous EPO on the survival of RGCs after ocular hypertension injury.


Immunohistochemistry studies identified Müller cells as the main source of EPO in the normal retina. Expression of EPO and EPOR proteins was increased significantly 2 weeks after ocular hypertension. RGCs, amacrine and bipolar cells all demonstrated an increased expression of EPOR after ocular hypertension. Neutralization of endogenous EPO with soluble EPOR exacerbated ocular hypertensive injury, suggesting a role of the EPO/EPOR system in the survival of RGCs after injury. Similarly, topical and systemic administration of recombinant human EPO rescues RGCs after chronic ocular hypertension.


These results indicate that an endogenous EPO/EPOR system participates in intrinsic recovery mechanisms after retina injury and RGCs might be rescued by exogenous administration of EPO.


Erythropoietin Erythropoietin receptor Retinal ganglion cell Glaucoma Intraocular pressure Endogenous Neuroprotectant 



We gratefully acknowledge Dr. Daniel HS Lee from Biogen Idec, Inc. USA for his valuable comments. This research is supported by a donation from the Hong Kong Eye Charitable Foundation, and Ms. Annie Tso Wen Wei.


  1. Becerra SP, Amaral J (2002) Erythropoietin – an endogenous retinal survival factor. N Engl J Med 347:1968–1970PubMedCrossRefGoogle Scholar
  2. Bernaudin M, Marti HH, Roussel S, Divoux D, Nouvelot A, MacKenzie ET, Petit E (1999) A potential role for erythropoietin in focal permanent cerebral ischemia in mice. J Cereb Blood Flow Metab 19:643–651PubMedCrossRefGoogle Scholar
  3. Bocker-Meffert S, Rosenstiel P, Rohl C, Warneke N, Held-Feindt J, Sievers J, Lucius R (2002) Erythropoietin and VEGF promote neural outgrowth from retinal explants in postnatal rats. Invest Ophthalmol Vis Sci 43:2021–2026PubMedGoogle Scholar
  4. Brines ML, Ghezzi P, Keenan S, Agnello D, de Lanerolle NC, Cerami C, Itri LM, Cerami A (2000) Erythropoietin crosses the blood–brain barrier to protect against experimental brain injury. Proc Natl Acad Sci USA 97:10526–10531PubMedCrossRefGoogle Scholar
  5. Buemi M, Cavallaro E, Floccari F, Sturiale A, Aloisi C, Trimarchi M, Grasso G, Corica F, Frisina N (2002) Erythropoietin and the brain: from neurodevelopment to neuroprotection. Clin Sci (Lond) 103:275–282Google Scholar
  6. Cheung ZH, Chan YM, Siu FK, Yip HK, Wu W, Leung MC, So KF (2004) Regulation of caspase activation in axotomized retinal ganglion cells. Mol Cell Neurosci 25:383–393PubMedCrossRefGoogle Scholar
  7. Dawson TM (2002) Preconditioning-mediated neuroprotection through erythropoietin? Lancet 359:96–97PubMedCrossRefGoogle Scholar
  8. Diem R, Sattler MB, Merkler D, Demmer I, Maier K, Stadelmann C, Ehrenreich H, Bahr M (2005) Combined therapy with methylprednisolone and erythropoietin in a model of multiple sclerosis. Brain 128:375–385PubMedCrossRefGoogle Scholar
  9. Erbayraktar S et al (2003) Asialoerythropoietin is a nonerythropoietic cytokine with broad neuroprotective activity in vivo. Proc Natl Acad Sci USA 100:6741–6746PubMedCrossRefGoogle Scholar
  10. Gorio A, Gokmen N, Erbayraktar S, Yilmaz O, Madaschi L, Cichetti C, Di Giulio AM, Vardar E, Cerami A, Brines M (2002) Recombinant human erythropoietin counteracts secondary injury and markedly enhances neurological recovery from experimental spinal cord trauma. Proc Natl Acad Sci USA 99:9450–9455PubMedCrossRefGoogle Scholar
  11. Grasso G, Sfacteria A, Erbayraktar S, Passalacqua M, Meli F, Gokmen N, Yilmaz O, La TD, Buemi M, Iacopino DG, Coleman T, Cerami A, Brines M, Tomasello F (2006) Amelioration of spinal cord compressive injury by pharmacological preconditioning with erythropoietin and a nonerythropoietic erythropoietin derivative. J Neurosurg Spine 4:310–318PubMedCrossRefGoogle Scholar
  12. Grimm C, Wenzel A, Groszer M, Mayser H, Seeliger M, Samardzija M, Bauer C, Gassmann M, Reme CE (2002) HIF-1-induced erythropoietin in the hypoxic retina protects against light-induced retinal degeneration. Nat Med 8:718–724PubMedCrossRefGoogle Scholar
  13. Grimm C, Wenzel A, Stanescu D, Samardzija M, Hotop S, Groszer M, Naash M, Gassmann M, Reme C (2004) Constitutive overexpression of human erythropoietin protects the mouse retina against induced but not inherited retinal degeneration. J Neurosci 24:5651–5658PubMedCrossRefGoogle Scholar
  14. Jelkmann W, Metzen E (1996) Erythropoietin in the control of red cell production. Ann Anat 178:391–403PubMedGoogle Scholar
  15. Ji JZ, Elyaman W, Yip HK, Lee VW, Yick LW, Hugon J, So KF (2004) CNTF promotes survival of retinal ganglion cells after induction of ocular hypertension in rats: the possible involvement of STAT3 pathway. Eur J Neurosci 19:265–272PubMedCrossRefGoogle Scholar
  16. Junk AK, Mammis A, Savitz SI, Singh M, Roth S, Malhotra S, Rosenbaum PS, Cerami A, Brines M, Rosenbaum DM (2002) Erythropoietin administration protects retinal neurons from acute ischemia-reperfusion injury. Proc Natl Acad Sci USA 99:10659–10664PubMedCrossRefGoogle Scholar
  17. Juul SE, Anderson DK, Li Y, Christensen RD (1998) Erythropoietin and erythropoietin receptor in the developing human central nervous system. Pediatr Res 43:40–49PubMedCrossRefGoogle Scholar
  18. Kilic U, Kilic E, Soliz J, Bassetti CI, Gassmann M, Hermann DM (2005) Erythropoietin protects from axotomy-induced degeneration of retinal ganglion cells by activating ERK-1/-2. FASEB J 19:249–251PubMedGoogle Scholar
  19. Kocsis I, Treszl A, Vasarhelyi B (2005) Role of erythropoietin in brain homeostasis, neurodevelopment and neuroprotection. Orv Hetil 146:2527–2532PubMedGoogle Scholar
  20. Kretz A, Happold CJ, Marticke JK, Isenmann S (2005) Erythropoietin promotes regeneration of adult CNS neurons via Jak2/Stat3 and PI3K/AKT pathway activation. Mol Cell Neurosci 29:569–579PubMedCrossRefGoogle Scholar
  21. Morrison JC, Johnson EC, Cepurna W, Jia L (2005) Understanding mechanisms of pressure-induced optic nerve damage. Prog Retin Eye Res 24:217–240PubMedCrossRefGoogle Scholar
  22. Osborne NN, Ugarte M, Chao M, Chidlow G, Bae JH, Wood JP, Nash MS (1999) Neuroprotection in relation to retinal ischemia and relevance to glaucoma. Surv Ophthalmol 43(Suppl 1):S102–S128PubMedCrossRefGoogle Scholar
  23. Quigley HA, Nickells RW, Kerrigan LA, Pease ME, Thibault DJ, Zack DJ (1995) Retinal ganglion cell death in experimental glaucoma and after axotomy occurs by apoptosis. Invest Ophthalmol Vis Sci 36:774–786PubMedGoogle Scholar
  24. Rex TS, Allocca M, Domenici L, Surace EM, Maguire AM, Lyubarsky A, Cellerino A, Bennett J, Auricchio A (2004) Systemic but not intraocular Epo gene transfer protects the retina from light-and genetic-induced degeneration. Mol Ther 10:855–861PubMedCrossRefGoogle Scholar
  25. Sadamoto Y, Igase K, Sakanaka M, Sato K, Otsuka H, Sakaki S, Masuda S, Sasaki R (1998) Erythropoietin prevents place navigation disability and cortical infarction in rats with permanent occlusion of the middle cerebral artery. Biochem Biophys Res Commun 253:26–32PubMedCrossRefGoogle Scholar
  26. Sakanaka M, Wen TC, Matsuda S, Masuda S, Morishita E, Nagao M, Sasaki R (1998) In vivo evidence that erythropoietin protects neurons from ischemic damage. Proc Natl Acad Sci USA 95:4635–4640PubMedCrossRefGoogle Scholar
  27. Sattler MB, Merkler D, Maier K, Stadelmann C, Ehrenreich H, Bahr M, Diem R (2004) Neuroprotective effects and intracellular signaling pathways of erythropoietin in a rat model of multiple sclerosis. Cell Death Differ 11(Suppl 2):S181–S192PubMedCrossRefGoogle Scholar
  28. Schori H, Kipnis J, Yoles E, WoldeMussie E, Ruiz G, Wheeler LA, Schwartz M (2001) Vaccination for protection of retinal ganglion cells against death from glutamate cytotoxicity and ocular hypertension: implications for glaucoma. Proc Natl Acad Sci USA 98:3398–3403PubMedCrossRefGoogle Scholar
  29. Siren AL, Ehrenreich H (2001) Erythropoietin – a novel concept for neuroprotection. Eur Arch Psychiatry Clin Neurosci 251:179–184PubMedCrossRefGoogle Scholar
  30. Siren AL, Fratelli M, Brines M, Goemans C, Casagrande S, Lewczuk P, Keenan S, Gleiter C, Pasquali C, Capobianco A, Mennini T, Heumann R, Cerami A, Ehrenreich H, Ghezzi P (2001) Erythropoietin prevents neuronal apoptosis after cerebral ischemia and metabolic stress. Proc Natl Acad Sci USA 98:4044–4049PubMedCrossRefGoogle Scholar
  31. Sommer A (1989) Intraocular pressure and glaucoma. Am J Ophthalmol 107:186–188PubMedGoogle Scholar
  32. Tsai JC, Wu L, Worgul B, Forbes M, Cao J (2005) Intravitreal administration of erythropoietin and preservation of retinal ganglion cells in an experimental rat model of glaucoma. Curr Eye Res 30:1025–1031PubMedCrossRefGoogle Scholar
  33. Wang X, Zhu C, Wang X, Gerwien JG, Schrattenholz A, Sandberg M, Leist M, Blomgren K (2004) The nonerythropoietic asialoerythropoietin protects against neonatal hypoxia-ischemia as potently as erythropoietin. J Neurochem 91:900–910PubMedCrossRefGoogle Scholar
  34. Weishaupt JH, Rohde G, Polking E, Siren AL, Ehrenreich H, Bahr M (2004) Effect of erythropoietin axotomy-induced apoptosis in rat retinal ganglion cells. Invest Ophthalmol Vis Sci 45:1514–1522PubMedCrossRefGoogle Scholar
  35. WoldeMussie E, Ruiz G, Wijono M, Wheeler LA (2001) Neuroprotection of retinal ganglion cells by brimonidine in rats with laser-induced chronic ocular hypertension. Invest Ophthalmol Vis Sci 42:2849–2855PubMedGoogle Scholar
  36. Yamasaki M, Mishima HK, Yamashita H, Kashiwagi K, Murata K, Minamoto A, Inaba T (2005) Neuroprotective effects of erythropoietin on glutamate and nitric oxide toxicity in primary cultured retinal ganglion cells. Brain Res 1050:15–26PubMedCrossRefGoogle Scholar
  37. Zhong L, Bradley J, Schubert W, Ahmed E, Adamis AP, Shima DT, Robinson GS, Ng YS (2007) Erythropoietin promotes survival of retinal ganglion cells in DBA/2J glaucoma mice. Invest Ophthalmol Vis Sci 48:1212–1218PubMedCrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC 2007

Authors and Affiliations

  • Qing-Ling Fu
    • 1
    • 2
  • Wutian Wu
    • 1
    • 2
  • Hua Wang
    • 1
    • 2
  • Xin Li
    • 1
    • 2
  • Vincent W. H. Lee
    • 3
  • Kwok-Fai So
    • 1
    • 2
    Email author
  1. 1.Department of AnatomyThe University of Hong Kong Li Ka Shing Faculty of MedicinePokfulamHong Kong SAR, China
  2. 2.The State Key Laboratory of Brain and Cognitive sciencesThe University of Hong KongPokfulamHong Kong SAR, China
  3. 3.Eye CentreHong Kong Adventist HospitalHong KongHong Kong SAR, China

Personalised recommendations