Changes in Adrenomedullin in Patients with Proliferative Diabetic Retinopathy

Abstract

Purpose: To measure adrenomedullin (ADM) levels in the blood, vitreous fluid and fibrous membrane in patients with proliferative diabetic retinopathy (PDR) and study its changes in different pathological conditions.Methods: We used radioimmunoassay technique to determine immunoreactive- adrenomedullin (IR-ADM) concentrations in the plasma, vitreous samples and fibrous membrane obtained from 9 control subjects with idiopathic macular hole and 23 patients with PDR undergoing vitrectomy.Results: IR-ADM levels in the plasma, vitreous samples and fibrous membrane tissues (16.1 ± 2.91fmol/ml, 9.80 ± 2.51fmol/ml and 34.8 ± 5.22fmol/mg) were all significantly elevated in patients with PDR compared with control subjects (11.6 ± 2.38 fmol/ml, 5.8 ± 1.64 fmol/ml and 22.4 ± 1.72 fmol/mg). The levels of ADM in vitreous were also significantly higher in PDR patients with diabetic macular edema (DME) (11.2 ± 2.36 fmol/ml) than those of patients without DME (8.0 ± 1.11 fmol/ml) and controls (5.8 ± 1.64 fmol/ml).Conclusions: These findings suggest that ADM may be produced locally in the eyes and may correlate with the severity and proliferative reactions of diabetic retinopathy.