Vascular Cell Adhesion Molecule-1 (VCAM-1) contributes to macular fibrosis in neovascular age-related macular degeneration through modulating macrophage functions.

BACKGROUND: Neovascular age-related macular degeneration (nAMD) is a major cause of blindness in the elderly. The disease is due to the growth of abnormal blood vessels into the macula, leading to the loss of central vision. Intravitreal injection of vascular endothelial growth factor (VEGF) inhibitors (e.g., anti-VEGF) is the standard of care for nAMD. However, nearly 50% of patients do not respond or respond poorly to the therapy. More importantly, up to 70% of nAMD patients develop macular fibrosis after 10 years of anti-VEGF therapy. The underlying mechanism of nAMD-mediated macular fibrosis is unknown although inflammation is known to play an important role in the development of abnormal macular blood vessels and its progression to fibro-vascular membrane. In this study, we measured the intraocular levels of adhesion molecule VCAM-1, ICAM-1, CD44, CD62L, and CD62P in nAMD patients with and without macular fibrosis and investigated the link between the levels of adhesion molecule and clinical features (e.g., visual improvement, retinal thickness, etc.). We further investigated the effect of VCAM-1 in macrophage function in vitro and the development of subretinal fibrosis in vivo using a two-stage laser-induced protocol. RESULTS: The aqueous levels of ICAM-1, VCAM-1, CD44, and CD62L were significantly higher in nAMD patients compared to cataract controls. The aqueous level of VCAM-1 (but not other adhesion molecules) was significantly higher in patients with macular fibrosis than those without and the level correlated positively with the retinal thickness. VCAM-1 was highly expressed at the lesion site in the mouse model of subretinal fibrosis. Blocking VCAM-1 or its receptor VLA-4 significantly prevented macrophage infiltration and reduced subretinal fibrosis in vivo. VCAM-1 induced macrophage migration and upregulated the expression of Arg-1, Mmp12 and Il6 but down-regulated the expression of iNOS and Il1b in macrophages. CONCLUSIONS: VCAM-1 may contribute to the development of macular fibrosis in nAMD patients by modulating macrophage functions, including migration and profibrotic polarization.

Higher Aqueous Levels of Resistin and Lipocalin-2 Indicated Worse Visual Improvement following anti-VEGF Therapy in Patients with Retinal Vein Occlusion.

PURPOSE: The aim of this study was to investigate the aqueous humor levels of elastase-2, lactoferrin, lipocalin-2 (LCN-2), resistin, and thrombospondin-1 (TSP-1) in patients with retinal vein occlusion (RVO) and their relationship with visual prognosis following intravitreal anti-vascular endothelial growth factor (VEGF) therapy. MATERIALS AND METHODS: 52 RVO patients (23 cases of central retinal vein occlusion (CRVO) and 29 cases of branch retinal vein occlusion (BRVO)) and 20 cases of senile cataract were enrolled in this study. All RVO patients underwent fundus examinations before and 6-8 months after intravitreal anti-VEGF treatment. Five milliliters of blood were collected from RVO patients before treatment for the measurement of lipids and coagulation factors. Sixty microliters of aqueous humor were collected during intravitreal injection of anti-VEGF or during cataract surgery. The levels of elastase-2, lactoferrin, LCN-2, resistin, and TSP-1 in aqueous humor were determined by Luminex xMAP multiple analysis. RESULTS: The aqueous levels of resistin and LCN-2 were significantly higher but the level of TSP-1 was significantly lower in RVO patients compared to controls. Further, sub-group analysis showed that CRVO patients had significantly higher levels of resistin and LCN-2 than controls. The aqueous levels of resistin and LCN-2 were negatively correlated with visual improvement following anti-VEGF therapy in CRVO but not in BRVO patients. Visual improvement in RVO patients was not associated with blood lipid levels or any of the coagulation factors. CONCLUSION: CRVO patients had significantly higher aqueous levels of resistin and LCN-2, which negatively impacted on visual improvement after anti-VEGF therapy.

[Expression of suppressor of cytokine signaling in peripheral blood monocular cells of patients with Vogt-Koyanagi-Harada disease].

OBJECTIVE: To investigate suppressor of cytokine signaling (SOCS) mRNA and protein expression in peripheral blood mononuclear cells (PBMC) of patients with Vogt-Koyanagi-Harada (VKH) disease. METHODS: Blood samples were taken from 15 VKH patients with active uveitis, 17 quiescent patients and 16 healthy individuals. IFN-gamma, IL-12 and IL-4 in the serum were measured by ELISA. PBMC were subjected to analysis of SOCS mRNA and protein expression using quantitative RT-PCR and western blot, respectively. RESULTS: The level of IL-4 in the serum of VKH patients and in controls were (28.40 +/- 5.93) ng/L, (34.5 +/- 9.47) ng/L and (11.25 +/- 4.43) ng/L, IL-12 were (24.33 +/- 8.55) ng/L, (11.53 +/- 6.11) ng/L and (5.19 +/- 2.43) ng/L, IFN-gamma were (18.05 +/- 2.23) ng/L, (15.53 +/- 2.63) ng/L and (1.61 +/- 3.47) ng/L, respectively. The level of IFN-gamma, IL-12 and IL-4 were all significantly higher in the serum of VKH patients than in controls(P < 0.01). IL-4 in quiescent patients was higher than in active patients (P < 0.01), IL-12 and IFN-gamma were lower in quiescent patients was higher than in active patients (P < 0.01, P < 0.05). Cytokine inducible SH2 containing protein (CIS) mRNA, SOCS1 mRNA, SOCS2 mRNA, SOCS3 mRNA and SOCS5 mRNA levels in PBMC of VKH patients with active uveitis are 0.72, 4.92, 1.09, 0.75 and 1.15 folds than that in healthy volunteers, respectively. They are 1.15, 2.25, 1.40, 0.69 and 1.16 folds in static patients, respectively. Marked decreased expression of CIS protein is detected in both active and quiescent patients with no significant difference between two groups (both P < 0.01). SOCS1 protein is up-regulated significantly in active patients compares to in quiescent patients nor in healthy volunteers (P < 0.01, P < 0.05). SOCS3 protein is significantly decreased in patients than in controls (both P < 0.05). SOCS5 protein is much higher in patients than in controls (both P < 0.01), and even higher in quiescent patients than in active episode (P < 0.05). CONCLUSIONS: Up regulation of SOCS1 and SOCS5 expression and down-regulation of SOCS3 and CIS may correlate with the development of a Th1 mediated immune response in VKH disease. There is insidious inflammation in VKH patients with clinically quiescent uveitis, and this may be one of the causes of persistence and recurrences of uveitis.

[Expression of suppressor of cytokine signaling in retina of experimental autoimmune uveoretinitis].

OBJECTIVE: To investigate the expression and significance of suppressor of cytokine signaling (SOCS) mRNA and protein in retina of rats with experimental autoimmune uveoretinitis (EAU). METHODS: Research was designed with randomized controlled trials. Eighty Lewis rats were immunized with interphotoreceptor retinoid-binding protein (IRBP) to induce EAU. They were stratified randomly into two groups: nontreatment group (40 rats) and treatment group (40 rats). The treatment group was administered cyclosporine A 20 mg.kg(-1).day(-1) after immunization for 28 days, and the nontreatment group received saline buffer in the same way, ten normal Lewis rats without immunization and treatment as normal control group. The rats in both groups were stratified randomly into four sub-groups. Each sub-group had 10 rats and the rats were sacrificed at day 0, 7, 14, 21, 28 after immunization. All eyes were evaluated by slit-lamp microscopy. Retinas of rats were subjected to analysis of SOCS mRNA and protein expression using quantitative RT-PCR and western blot, respectively. IL-4, IL-12 and IFN-gamma in the serum were measured by ELISA. RESULTS: At day 14, the nontreatment group developed acute anterior uveitis and showed typical signs including aqueous flare, small or irregular pupil due to posterior synechiae and hypopyon, the score of inflammation was 1.5 +/- 0.5; but the treatment group did not suffer from severe anterior chamber inflammation, the score of inflammation was 0.5 +/- 0.3. The highest level of IL-4, IL-12 and IFN-gamma production occurred at day 14 (P < 0.05), followed by decline in the secretion of IL-12 and IFN-gamma secretion to the baseline at day 28, while the concentration of IL-4 did not decrease significantly in the nontreatment group (P > 0.05). IL-12 and IFN-gamma did not change significantly (P > 0.05) and IL-4 production reached the highest level at day 28 in the treatment group. Both SOCS1 and CIS mRNA increased to the highest level at day 14. Compared to normal controls, the copies of SOCS1 and CIS mRNA were 3.41 fold and 3.36 fold in the nontreatment group, and were only 1.44 fold and 1.73 fold in treatment group, respectively. Both SOCS3 and SOCS5 mRNA reached the highest level at day 28 after immunization in both groups. The copies of SOCS3 and SOCS5 mRNA were 1.95 fold and 3.16 fold in the nontreatment group, and were 1.59 fold and 3.58 fold in the treatment group, respectively. Marked increased expression of SOCS1 and CIS proteins in the nontreatment group as compared to normal controls was detected at 7, 14, 21 days; in the treatment group these proteins only increased significantly at day 14 (P < 0.05). Expression of SOCS3 and SOCS5 proteins in both groups were higher than those in normal controls (P > 0.05). CONCLUSIONS: Marked increased expression of SOCS1 of retina may involve in the development of a Th1 mediated immune response in EAU. CIS and SOCS3 of retina may play important roles in mitigating pathogenic effects of proinflammatory cytokines during different stages of EAU. Up-regulation of SOCS5 may have protective functions.