Effect of serum cytokines and VEGF levels on diabetic retinopathy and macular thickness.
OBJECTIVE
To investigate the role of serum inflammatory cytokines and vascular endothelial growth factor (VEGF) in diabetic retinopathy (DR) and evaluate their relationship with macular thickness measurements obtained with optical coherence tomography (OCT).


METHODS
The study enrolled 28 healthy subjects (Group 1), 31 patients without DR (Group 2), 49 patients with nonproliferative DR (Group 3), and 46 patients with proliferative DR (Group 4). Macular profile was assessed with Stratus OCT-3 and the serum concentrations of VEGF and interleukin-1 alpha (IL-1 alpha), interleukin-6 (IL-6), interleukin-8 (IL-8), interleukin-10 (IL-10), macrophage inflammatory protein (MIP-1 alpha), monocyte chemoattractant protein (MCP-1), and epidermal growth factor (EGF) were measured using multiplex bead immunoassay.


RESULTS
The median value of the visual acuity was 20/20 (Groups 1 and 2), and 20/100 (Group 3), and 20/125 (Group 4). The median value of central subfield macular thickness was estimated as 165.50 microm in Group 1, 202.5 microm in Group 2, 318 microm in Group 3, and 310 microm in Group 4. The median serum VEGF level, which was 98.20 pg/ml in Group 1, demonstrated a progressive rise to 125.37 pg/ml in Group 2, to 153.07 pg/ml in Group 3, and to 149.12 pg/ml in Group 4. Statistical significance was found between all groups (p<0.05) except between Groups 3 and 4 (p=0.87). The median levels of IL-1 alpha and IL-6 were zero in all groups. The median serum levels of IL-8, IL-10, MIP-1 alpha, and EGF revealed a wide range within each group but no statistical significance between the groups (p>0.05). The median serum levels of IL-8, IL-10, MIP-1 alpha, and EGF revealed a wide range within each group, however, no statistically significant relationship was found between the groups (p>0.05). The median values of the serum MCP-1 concentrations presented a statistically significant rise with the progression of DR (p=0.02). No correlation was found between macular thickness and serum cytokine and VEGF levels (p>0.05).


CONCLUSIONS
Increased serum levels of VEGF and MCP-1 may act as a key regulator of DR and provide a potential tool for risk assessment in diabetic patients. Further studies that evaluate both vitreous and serum levels in various stages of DR are needed to provide a better understanding of the interaction between systemic and local inflammatory and angiogenic factors.
Ozturk
Banu Turgut
BT
Department of Ophthalmology, Meram Faculty of Medicine, Selcuk University, Konya, Turkey. ozturkbanuturgut@yahoo.com
Bozkurt
Banu
B
Kerimoglu
Hurkan
H
Okka
Mehmet
M
Kamis
Umit
U
Gunduz
Kemal
K
D018932:Chemokine CCL2 / Q000097:blood; D016207:Cytokines / Q000097:blood*; D003930:Diabetic Retinopathy / Q000097:blood* / Q000503:physiopathology; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D008266:Macula Lutea / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D042461:Vascular Endothelial Growth Factor A / Q000097:blood*; D014792:Visual Acuity
D018932:Chemokine CCL2; D016207:Cytokines; D006442:Glycated Hemoglobin; D042461:Vascular Endothelial Growth Factor A; C111835:CCL2 protein, human; C517652:hemoglobin A1c protein, human