Effect of topical administration of the microneurotrophin BNN27 in the diabetic rat retina

  • Ruth Ibán-Arias
  • Silvia Lisa
  • Smaragda Poulaki
  • Niki Mastrodimou
  • Ioannis Charalampopoulos
  • Achille Gravanis
  • Kyriaki ThermosEmail author
Basic Science



Diabetic retinopathy (DR) is a complex eye disease associated with diabetes mellitus. It is characterized by three pathophysiological components, namely microangiopathy, neurodegeneration, and inflammation. We recently reported that intraperitoneal administration of BNN27, a novel neurosteroidal microneurotrophin, reversed the diabetes-induced neurodegeneration and inflammation in rats treated with streptozotocin (STZ), by activating the NGF TrkA and p75 receptors. The aim of the present study was to investigate the efficacy of BNN27 to protect retinal neurons when applied topically as eye drops in the same model.


The STZ rat model of DR was employed. BNN27 was administered as eye drops to diabetic Sprague-Dawley rats for 7 days, 4 weeks post-STZ (70 mg/kg) injection. Immunohistochemistry and western blot analyses were employed to examine the viability of retinal neurons in control, diabetic, and diabetic-treated animals and the involvement of the TrkA receptor and its downstream signaling ERK1/2 kinases, respectively.


BNN27 reversed the STZ-induced attenuation of the immunoreactive brain nitric oxide synthetase (bNOS)- and tyrosine hydroxylase (TH)-expressing amacrine cells and neurofilament (NFL)-expressing ganglion cell axons in a dose-dependent manner. In addition, BNN27 activated/phosphorylated the TrkA receptor and its downstream prosurvival signaling pathway, ERK1/2 kinases.


The results of this study provide solid evidence regarding the efficacy of BNN27 as a neuroprotectant to the diabetic retina when administered topically, and suggest that its pharmacodynamic and pharmacokinetic profiles render it a putative therapeutic for diabetic retinopathy.


Retinal disease Nerve growth factor TrkA receptor Neurodegeneration Neuroprotection ERK1/2 kinases 


Authors’ contributions

KT conceived, designed the experiments, interpreted the data, wrote the manuscript, and supervised the project and is the guarantor of this study. RIA performed experiments, analyzed and interpreted the data, and wrote the manuscript with KT. SL performed experiments, and analyzed and interpreted the data. SP and NM performed experiments and analyzed the data. IC interpreted data and edited the manuscript. AG edited the manuscript. All authors significantly revised, edited, and read the final version of the manuscript.

Funding information

This study was co-financed by a grant to K.T from the European Union (European Social Fund-ESF) and Greek National Funds through the Operational Program “Education and Lifelong Learning” of the National Strategic Reference Framework (NSRF) – Research Funding Program: ARISTEIA II.

Compliance with ethical standards

Ethical approval

All applicable international, national, and/or institutional guidelines for the care and use of animals were followed.

Conflict of interest

Dr. Achille Gravanis is the co-founder of Bionature EA LTD, proprietor of compound BNN27 (patented with the WO 2008/1555 34 A2 number at the World Intellectual Property Organization). Dr. Ioannis Charalampopoulos has a patent WO 2008/1555 34 A2 with royalties paid. All other authors have no conflict of interest.


  1. 1.
    Yau JW, Rogers SL, Kawasaki R et al (2012) META-analysis for eye disease (META-EYE) study group. Diabetes Care 35:556–564CrossRefGoogle Scholar
  2. 2.
    Antonetti DA, Barber AJ, Bronson SK et al (2006) Diabetic retinopathy seeing beyond glucose-induced microvascular disease. Diabetes. 55:2041–2411CrossRefGoogle Scholar
  3. 3.
    Antonetti DA, Klein R, Gardner TW (2012) Mechanisms of disease diabetic retinopathy. N Engl J Med 366:1227–1239CrossRefGoogle Scholar
  4. 4.
    Barber AJ, Lieth E, Khin SA, Antonetti DA, Buchanan AG, Gardner TW, The Penn State Retina Research Group (1998) Neural apoptosis in the retina during experimental and human diabetes. Early onset and effect of insulin. J Clin Invest 102:783–791CrossRefGoogle Scholar
  5. 5.
    Simó R, Hernández C (2014) Neurodegeneration in the diabetic eye: new insights and therapeutic perspectives. Trends Endocrinol Metab 25:23–33CrossRefGoogle Scholar
  6. 6.
    Tang J, Kern TS (2011) Inflammation in diabetic retinopathy. Prog Retin Eye Res 30:343–358CrossRefGoogle Scholar
  7. 7.
    Solomon SD, Chew E, Duh EJ et al (2017) Diabetic retinopathy: a position statement by the American Diabetes Association. Diabetes Care 40:412–418CrossRefGoogle Scholar
  8. 8.
    Stitt AW, Curtis TM et al (2016) The progress in understanding and treatment of diabetic retinopathy. Prog Retinal Eye Res 51:156–186CrossRefGoogle Scholar
  9. 9.
    Park SH, Park JW, Park SJ et al (2003) Apoptotic death of photoreceptors in the streptozotocin-induced diabetic rat retina. Diabetologia 46:1260–1268CrossRefGoogle Scholar
  10. 10.
    Kizawa J, Machida S, Kobayashi T et al (2006) Changes of oscillatory potentials and photopic negative response in patients with early diabetic retinopathy. Jpn J 50(4):367–373Google Scholar
  11. 11.
    Carrasco E, Hernández C, Miralles A et al (2007) Lower somatostatin expression is an early event in diabetic retinopathy and is associated with retinal neurodegeneration. Diabetes Care 30:2902–2908CrossRefGoogle Scholar
  12. 12.
    Carrasco E, Hernández C, de Torres I et al (2008) Lowered cortistatin expression is an early event in the human diabetic retina and is associated with apoptosis and glial activation. Mol Vis 14:1496–1502Google Scholar
  13. 13.
    Simó R, Stitt AW, Gardner TW (2018) Neurodegeneration in diabetic retinopathy: does it really matter? Diabetologia 61:1902–1912CrossRefGoogle Scholar
  14. 14.
    Ibán-Arias R, Lisa S, Mastrodimou N et al. (2018) The synthetic microneurotrophin BNN27 affects retinal function in rats with streptozotocin-induced diabetes. Diabetes 67(2):321–333Google Scholar
  15. 15.
    Calogeropoulou T, Avlonitis N, Minas V et al (2009) Novel dehydroepiandrosterone derivatives with antiapoptotic, neuroprotective activity. J Med Chem 52:6569–6587CrossRefGoogle Scholar
  16. 16.
    Pediaditakis I, Efstathopoulos P, Prousis KC et al (2016a) Selective and differential interactions of BNN27, a novel C17-spiroepoxy steroid derivative, with TrkA receptors, regulating neuronal survival and differentiation. Neuropharmacol 111:266–282CrossRefGoogle Scholar
  17. 17.
    Pediaditakis I, Kourgiantaki A, Prousis KC et al (2016b) BNN27, a 17-spiroepoxy steroid derivative, interacts with and activates p75neurotrophin receptor, rescuing cerebellar granule neurons from apoptosis. Front Pharmacol.
  18. 18.
    Bennett J, O’Brien L, Brohawn D (2016) Pharmacological properties of microneurotrophin drugs developed for treatment of amyotrophic lateral sclerosis. Biochem Pharmacol 117:68–77CrossRefGoogle Scholar
  19. 19.
    Kokona D, Charalampopoulos I, Pediaditakis I et al (2012) The neurosteroid dehydroepiandrosterone (DHEA) protects the retina from AMPA-induced excitotoxicity: NGF TrkA receptor involvement. Neuropharmacol 62:2106–2117CrossRefGoogle Scholar
  20. 20.
    Mysona BA, Shanab A, Elshaer S, El-Remessy AB (2014) Nerve growth factor in diabetic retinopathy: beyond neurons. Expert Rev Ophthalmol 9:99–107CrossRefGoogle Scholar
  21. 21.
    Bonetto G, Charalampopoulos I, Gravanis A, Karagogeos D (2017) The novel synthetic microneurotrophin BNN27 protects mature oligodendrocytes against cuprizone-induced death, through the NGF receptor TrkA. Glia 65:1376–1394.24CrossRefGoogle Scholar
  22. 22.
    Tsoka P, Matsumoto H, Maidana DE et al (2018) Effects of BNN27, a novel C17-spiroepoxy steroid derivative, on experimental retinal detachment-induced photoreceptor cell death. Sci Rep 8:10661.25CrossRefGoogle Scholar
  23. 23.
    Akiyama H, Nakazawa T, Shimura M et al (2002) Presence of mitogen-activated protein kinase in retinal Müller cells and its neuroprotective effect ischemia-reperfusion injury. Neuroreport 13:2103–2107CrossRefGoogle Scholar
  24. 24.
    Hernández C, García-Ramírez M, Corraliza L et al (2013) Topical administration of somatostatin prevents retinal neurodegeneration in experimental diabetes. Diabetes. 62:2569–2578CrossRefGoogle Scholar
  25. 25.
    Kiagiadaki F, Thermos K (2008) Effect of intravitreal administration of somatostatin and sst2 analogs on AMPA-induced neurotoxicity in rat retina. Invest Ophthalmol Vis Sci 49:3080–3089CrossRefGoogle Scholar
  26. 26.
    Bogdanov P, Simó-Servat O, Sampedro J et al (2018) Topical administration of bosentan prevents retinal neurodegeneration in experimental diabetes. Int J Mol Sci 19:3578. CrossRefGoogle Scholar
  27. 27.
    Lambiase A, Aloe L, Centofanti M et al (2009) Experimental and clinical evidence of neuroprotection by nerve growth factor eye drops: implications for glaucoma. Proc Natl Acad Sci U S A 106:13469–13474CrossRefGoogle Scholar
  28. 28.
    Colafrancesco V, Parisi V, Sposato V et al (2011) Ocular application of nerve growth factor protects degenerating retinal ganglion cells in a rat model of glaucoma. J Glaucoma 20:100–108CrossRefGoogle Scholar
  29. 29.
    Mesentier-Louro LA, Rosso P, Carito V et al. (2019) Nerve growth factor role on retinal ganglion cell survival and axon regrowth: effects of ocular administration in experimental model of optic nerve injury. Mol Neurobiol 56: 1056.
  30. 30.
    Tirassa P, Rosso P, Iannitelli A (2018) Ocular nerve growth factor (NGF) and NGF eye drop application as paradigms to investigate NGF neuroprotective and reparative actions. In: Skaper S (ed) Neurotrophic factors. Methods in molecular biology, vol 1727. Humana Press, New YorkGoogle Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Department of Pharmacology, School of MedicineUniversity of CreteHeraklionGreece
  2. 2.Department of Psychiatry, Laboratory of Molecular Biology and Genetics of NeurodegenerationIcahn School of Medicine at Mount SinaiNew YorkUSA
  3. 3.Department of Cell Biology and PathologyInstituto de Neurociencias de Castilla y León (INCyL) University of Salamanca & Institute of Biomedical ResearchSalamancaSpain
  4. 4.Institute of Molecular Biology & BiotechnologyFoundation of Research & Technology-Hellas (FORTH)HeraklionGreece

Personalised recommendations