Elevated adrenomedullin in the vitreous of patients with diabetic retinopathy

Adrenomedullin (AM) is a multifunctional peptide with various physiological actions, including vasodilatation, a defense mechanism against microorganisms, the regulation of growth and the regulation of insulin and glucose. In this study, we measured the vitreous AM levels in patients with diabetes mellitus to determine its potential involvement in the pathogenesis of diabetic retinopathy (DR). We used an immunoradiometric assay to measure the vitreous AM concentrations in a total of 28 eyes: 13 with DR and 15 with macular holes (15 men and 13 women, 62.9 ± 10.4 years old). The AM levels in the vitreous fluid of patients with DR (22.9 ± 7.9 fmol/ml) were found to be significantly higher than the corresponding AM levels in patients with macular holes (4.7 ± 1.1 fmol/ml) (p < 0.05). These results indicate that the increase in the vitreous AM is related to DR.