Vitreous and plasma changes of endothelin-1, adrenomedullin and vascular endothelium growth factor in patients with proliferative diabetic retinopathy

E.M. Vingolo, S. Fragiotta, M. Mafrici, A. Cutini, C. Marinelli, A. Concistrè, G. Iannucci, L. Petramala, C. Letizia

Department of Medical-Surgical Sciences and Biotechnologies, U.O.S. Ophthalmology, “Sapienza” University of Rome, Terracina, Italy. serena.fragiotta@uniroma1.it

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• Ophthalmology

OBJECTIVE: To assess vitreous and plasma changes of vascular endothelial growth factor A (VEGF-A), adrenomedullin (ADM) and endothelin-1 (ET-1) in proliferative diabetic retinopathy (PDR).

PATIENTS AND METHODS: 9 patients with PDR in type 2 diabetes (T2DM) and 11 age-matched non-diabetic patients were enrolled. The levels of VEGF-A, ADM and ET-1 were measured using an enzyme (ELISA) and a radioimmunoassay (RIA) both in vitreous and plasma samples.

RESULTS: Vitreous ADM and VEGF-A levels were significantly higher in PDR patients (p=0.04 and p=0.02), whereas no differences were found in ET-1 levels (p=0.29). Plasma ADM levels were significantly higher in the PDR group (p<0.01), whereas no significant differences were found in the plasma ET-1 and VEGF-A levels (p=0.30 and p=0.37). The ADM vitreous/plasma ratio was significantly reduced in PDR group.

CONCLUSIONS: The role of ET-1 in advanced PDR is still controversial; it has been supposed a role limited to induce hypoxic state and promote angiogenesis in the early phases. Once the neo-angiogenic process starts, other mediators are mainly involved as VEGF and ADM. Our findings suggest that ADM is an important marker of advanced PDR as well as VEGF. Conversely, ET-1 is not significantly involved in the advanced stage of PDR.

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