Vitreous inflammatory factors and serous retinal detachment in central retinal vein occlusion: a case control series

BACKGROUND: This study investigated whether the vitreous fluid levels of soluble vascular endothelial growth factor receptor-2 (sVEGFR-2), pigment epithelium-derived factor (PEDF), and soluble intercellular adhesion molecule 1 (sICAM-1) were associated with the occurrence of serous retinal detachment (SRD) in patients with central retinal vein occlusion (CRVO). METHODS: We recruited 33 patients with CRVO and macular edema, as well as 18 controls with nonischemic ocular diseases. Eighteen of the 33 patients with CRVO showed SRD on optical coherence tomography of the macula (defined as subretinal accumulation of fluid with low reflectivity), while the other 15 patients only had cystoid macular edema (CME, defined as hyporeflective intraretinal cavities). Retinal ischemia was evaluated by measuring the area of capillary non-perfusion using fluorescein angiography and the public domain Scion Image program, while central macular thickness (CMT) was examined by optical coherence tomography. Vitreous fluid samples were obtained during pars plana vitrectomy and levels of the target molecules were measured by enzyme-linked immunosorbent assay. RESULTS: Ischemia was significantly more common in the SRD group (17/18 patients) than in the CME group (5/15 patients) (P < 0.001). The vitreous fluid level of sICAM-1 increased significantly across the three groups from the control group (4.98 ± 1.73 ng/ml) to the CME group (15.4 ± 10.1 ng/ml) and the SRD group (27.1 ± 17.7 ng/ml) (p(trend)< 0.001). The vitreous fluid level of sVEGFR-2 also showed a significant increase across the three groups (1083 ± 541 pg/ml, 1181 ± 522 pg/ml, and 1535 ± 617 pg/ml, respectively, p(trend )= 0.019). On the other hand, the vitreous fluid level of PEDF showed a significant decrease across the three groups (56.4 ± 40.0 ng/ml, 24.3 ± 17.3 ng/ml, and 16.4 ± 12.6 ng/ml, respectively, p(trend)< 0.001). CONCLUSIONS: Higher levels of inflammatory factors (sICAM-1 and sVEGFR-2) and lower levels of anti-inflammatory PEDF were observed in macular edema patients with SRD, suggesting that inflammation plays a key role in determining the severity of CRVO.