الفهرس 
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Abstract
Diabetic retinopathy, a serious microvascular complication of DM, remains one of the leading causes of blindness throughout the world. It is characterized by microvascular damage and capillary non-perfusion resulting in retinal angiogenesis.
Pigment epithelium-derived factor (PEDF), a 50-kDa protein is a member of the serine protease inhibitor (serpin) family PEDF was first identified in the conditioned-medium of cultured human retinal pigment epithelial cells. It inhibits retinal endothelial cell growth, migration and suppresses ischemia-induced retinal neovascularization.
The aim of this work was to study the clinical significance of serum PEDF in patients with diabetes mellitus and its relevance of PEDF to the progression of diabetic retinopathy.
The present study was conducted on 60 diabetic patients who were recruited from the Ophthalmology Department at Ain Shams University Hospitals. The patients’ group was divided according to the international severity scale into 4 subgroups; non-apparent diabetic retinopathy, mild-to-moderate non-proliferative, severe non-proliferative, proliferative diabetic retinopathy, each subgroup included 15 patients. Healthy control group included 20 healthy subjects.
All the patients were subjected to full history taking, standard ophthalmic examination, ophthalmoscopy, fluorescein angiography, and laboratory investigations including glycated hemoglobin and lipid profile. Both patients’ and healthy control group were subjected the assay of PEDF by ELISA technique.
Serum PEDF level was significantly higher in the patients’ group compared to the control group. Moreover, the mean level of PEDF in the different patients’ subgroups was significantly different with gradual increase with the disease progression being highest among patients with PDR.
The correlation study showed the presence of a significant positive correlation between the serum PEDF level and the duration of the disease.
Receiver operating characteristic curve analysis was applied to assess the predictive utility of PEDF in the diabetic retinopathy patients, where the best cutoff to discriminate the complicated diabetic patients from the non-complicated was 9.1 µg/mL with a diagnostic sensitivity of 80%, diagnostic specificity of 86.6%, accuracy 81.6%. The AUC was 0.88.
The best cutoff for the prediction of intraocular hemorrhage was 10.1 µg/mL, this had a diagnostic sensitivity of 93.3%, diagnostic specificity of 80%, accuracy 88% and the AUC was 0.98. While, the best cutoff for the prediction of the progression from the non-proliferative stage to the proliferative was 12.3 µg/mL, this had a diagnostic sensitivity of 100%, diagnostic specificity of 83.3%, accuracy 86.6% and the AUC was 0.91.
In conclusion, serum PEDF is a useful diagnostic marker for diabetic retinopathy. Moreover, it has a promising prognostic role in the discrimination of different stages of the disease.