Vitreous levels of somatostatin in patients with chronic uveitic macular oedema

PurposeIntravitreal somatostatin (SST) levels are decreased in patients with diabetic macular oedema. This deficit may be involved in the pathogenesis of this condition. The aim of the present study was to determine SST concentration in the vitreous fluid of patients with chronic uveitic macular oedema (CUMO) and quiescent intraocular inflammation.MethodsPlasma and vitreous fluid samples were obtained during vitrectomy from 11 eyes of patients with CUMO and from 42 eyes of control subjects (idiopathic epiretinal membrane, macular hole). SST concentration was measured by radioimmunoassay. Statistics: χ 2 -square test, Mann-Whitney U-test, Wilcoxon test, Spearmans rank correlation coefficient, and multivariant linear regression models.ResultsPlasma SST concentrations were similar in uveitic patients and controls (28.25 pg/ml (21.3-31) vs 28.7 pg/ml (22-29.5); P0.869). A higher vitreous concentration of proteins was found in uveitic patients (1.59±0.38 mg/ml vs 0.73±0.32 mg/ml, P0.0001). Vitreous SST was markedly lower in uveitic patients, both in absolute terms and after adjusting for total intravitreous protein concentration (39.37 pg/ml (6.16-172) vs 486.73 pg/ml (4.7-1833), P0.0001; 33.1 pg/mg (3.9-215.74) vs 629.75 pg/mg (6.91-2024), P0.0001). No correlations were found between plasma and vitreous concentration of SST in either group (ρ0.191, P0.57 and ρ0.49, P0.66). There were no correlations between vitreous SST concentration and visual acuity or macular thickness in uveitic patients (ρ0.302, P0.31 and ρ0.45, P0.13).ConclusionsIntravitreous SST is decreased in patients with CUMO and quiescent intraocular inflammation. The deficit of SST may have a role in the pathogenesis of this condition. © 2012 Macmillan Publishers Limited All rights reserved.