Endocrine Abstracts

Introduction/aim: There is growing evidence to suggest that retinal neurodegeneration is an early event in the pathogenesis of diabetic retinopathy (DR). Somatostatin (SST) has a neuroprotective action and we previously found a downregulation of SST associated with the hallmarks of retinal neurodegeneration (glial activation and apoptosis) in human retinas. The aim of the study was to test the hypothesis that SST is useful in preventing retinal neurodegeneration.

Methods: Male Sprague–Dawley rats in which diabetes was induced by streptozotocin were treated with either eye-drops of SST (10 mg/ml; 20 μl/eye; n=8) or vehicle (n=8) for 15 days. Non-diabetic Sprague–Dawley rats (n=8) treated with vehicle served as control group. Electroretinography (ERG) studies were performed before starting treatment and one day prior death. Glial activation was evaluated by measuring glial fibrillar acidic protein (GFAP) by immunofluorescence. Apoptosis was assessed by TUNEL assay.

Results: Treatment with SST eye drops prevented ERG abnormalities (reduction in b-wave amplitude and increase in b-wave implicit time), as well as the characteristic features of neurodegeneration (glial activation and apoptosis) caused by diabetes. In fact, glial activation and apoptosis in diabetic rats treated with SST were similar than in non-diabetic rats.

Conclusion: SST eye drops prevented both functional and morphologic abnormalities in the diabetic retina. Based on these promising results in rats we have designed and initiated a multicentric clinical trial (EUROCONDOR. FP7-Health-2011-278040) in order to demonstrate the potential beneficial effects of SST topical administration in preventing or arresting DR development.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This work was supported, however funding details unavailable.