Elevated tumor necrosis factor in serum is associated with increased retinal ischemia in proliferative eales' disease.

OBJECTIVE: Tumor necrosis factor (TNF) was evaluated in the serum of patients with proliferative stage of Eales' disease to study its relation with the area of retinal capillary non-perfusion (ischemic retina). METHODS: Quantification of the levels of TNF was done using sandwich ELISA in 52 cases with proliferative Eales' disease and in 32 healthy controls. Seven 50° photographs of different fields of the fundus were taken on fluorescein angiography. The area of retinal capillary non-perfusion denoting retinal cell death was assessed in terms of optic disc areas. RESULTS: TNF levels were found to be significantly increased in the proliferative stage of the disease (mean 23.64 ± 3.7 pg/ml) as compared to controls (mean 12.49 ± 2.9 pg/ml; p < 0.001). Higher levels of TNF were found to be associated with an increased area of retinal capillary non-perfusion on fluorescein angiography. TNF levels of 20-31 pg/ml were observed in cases with neovascularization at the disc (n = 33) as compared to 17-21 pg/ml in cases with neovascularization elsewhere (n = 19). CONCLUSIONS: An increased level of TNF is associated with an increased area of the ischemic retina. It is hypothesized that retinal cell death signaling in proliferative Eales' disease is related to an increased TNF level.

Total antioxidant capacity in Eales' disease, uveitis & cataract.

BACKGROUND & OBJECTIVES: The human system possesses antioxidants that act harmoniously to neutralize the harmful oxidants. This study was aimed to evaluate the serum total antioxidant capacity (TAC) as a single parameter in Eales' disease (ED) and in an acute inflammatory condition such as uveitis and in cataract which is chronic, compared to healthy controls. METHODS: The TAC assay was done spectrophotometrically in the serum of Eales' disease cases (n=20) as well as in other ocular pathologies involving oxidative stress namely, uveitis and cataract (n=20 each). The oxidative stress measured in terms of TBARS, was correlated with the TAC. Individual antioxidants namely vitamin C, E and glutathione were also estimated and correlated with TAC. RESULTS: TAC was found to be significantly lower in Eales' disease with active vasculitis (0.28 ± 0.09 mM, P<0.001), Eales' disease with healed vasculitis (0.67 ± 0.09 mM), uveitis (0.46 ± 0.09 mM, P<0.001) and cataract (0.53 ± 0.1 mM, P=0.001) compared to the healthy controls, with a TAC level of 0.77 ± 0.09 mM. The TAC was found to correlate positively with vitamin E levels (P=0.05), GSH (P=0.02) but not with vitamin C, as seen in ED cases. In ED cases supplemented with vitamin E and C, there was a significant increase in the TAC level (P=0.02). INTERPRETATION & CONCLUSIONS: The TAC measurement provided a comprehensive assay for establishing a link between the antioxidant capacity and the risk of disease as well as monitoring antioxidant therapy. This method is a good substitute for assay of individual antioxidants as it clearly gives the status of the oxidative stress in the disease process.

Mannose-binding lectin as part of the complement pathway: characterization in non-inflamed and inflamed human eyes.

BACKGROUND: Mannose-binding lectin plays a central effector role in the lectin pathway of complement activation. Frequently occurring MBL2 polymorphisms result in mannose-binding lectin deficiency, which increases susceptibility to infection. We characterized mannose-binding lectin levels and function in non-inflamed and inflamed human eyes, and evaluated its relationship to blood mannose-binding lectin levels and function. DESIGN: Prospective, observational clinical study with controls and cases. PARTICIPANTS: Twenty-seven patients with paired blood and ocular samples (aqueous and/or vitreous) including 15 controls (non-inflamed) and 12 cases (inflamed). METHODS: Blood and ocular samples were collected from controls (n = 15) with quiet eyes during elective cataract surgery and cases with inflamed eyes including proven/suspected endophthalmitis (n = 11) and herpetic retinal vasculitis (n = 1). Mannan-binding and C4 deposition enzyme-linked quantify mannose-binding lectin levels and function. MAIN OUTCOME MEASURES: Blood and ocular mannose-binding lectin levels and function. RESULTS: Of 27 patients, 10 (37%) were mannose-binding lectin-deficient (defined as blood mannose-binding lectin levels <500 ng/mL). Blood mannose-binding lectin levels (P= 0.16) or function (P= 0.43) were not significantly different between controls and cases. As expected, there was a high correlation between blood mannose-binding lectin levels and function (r(2) = 0.74). However, there was significantly more mannose-binding lectin in inflamed eyes than non-inflamed eyes measured as level (P < 0.01) or C4 deposition function (P < 0.01). CONCLUSIONS: Our study demonstrated that mannose-binding lectin is significantly elevated in inflamed human eyes but virtually undetectable in non-inflamed control eyes, suggesting a role in sight-threatening ocular inflammation.

Assessment of gelatinase and tumor necrosis factor-α level in the vitreous and serum of patients with Eales disease: role of inflammation-mediated angiogenesis in the pathogenesis of Eales disease.

BACKGROUND: Eales disease (ED) is an idiopathic, inflammatory, venoocclusive disorder of peripheral retina resulting in retinal angiogenesis and vitreous hemorrhage. The objective of the present study is to investigate the expression and activation of gelatinase associated with the retinal neovascularization in ED and the relation between the levels of gelatinase and the cytokine tumor necrosis factor-α, known to upregulate matrix metalloproteinase (MMP) expression on various cells. METHODS: Vitreous and serum samples from 19 patients with ED who underwent retinal surgery were estimated for levels of MMP-2, MMP-9, tissue inhibitor of metalloproteinase-1, tissue inhibitor of metalloproteinase-2, and tumor necrosis factor-α by enzyme-linked immunosorbent assay method. Matrix metalloproteinase-2 and MMP-9 activities in serum and vitreous samples were evaluated by gelatin zymography method. Vitreous samples from 16 patients with macular hole undergoing vitrectomy were used as controls. RESULTS: Among the 2 gelatinase examined in vitreous and serum samples, only level and activity of MMP-9 were significantly higher in serum (P = 0.0001) and vitreous (P = 0.0002) samples of patients with ED than those of control subjects. Simultaneously, a positive correlation was found between intraocular tumor necrosis factor-α and MMP-9 concentration (Spearman correlation coefficient, r = 0.7040, P = 0.0023) in patients with ED. CONCLUSION: Increase in MMP-9 activity and its concentration in serum and vitreous of patients with ED compared with that of control subjects and correlation between intraocular levels of MMP-9 and tumor necrosis factor-α in patients with ED seem to provide a plausible explanation for inflammation-mediated angiogenesis during the development of this condition.

Interleukin-1 and tumor necrosis factor-alpha: novel targets for immunotherapy in Eales disease.

BACKGROUND: Eales disease is an idiopathic obliterative vasculopathy that primarily affects the peripheral retina of young adults. The authors evaluated interleukin 1 beta (IL-1beta), interleukin-6 (IL-6), Interleukin-10 (IL-10), and tumor necrosis factor-alpha (TNF-alpha) in the serum of patients with Eales disease stages for the first time. METHODS: The study group consisted of 45 consecutive patients of Eales disease [inflammatory stage (n = 15) and proliferative stage (n = 30)] and 28 healthy controls. Immunoassays for the quantification of the levels of four cytokines including IL-1beta, IL-6, IL-10, and TNF-alpha in the serum samples were performed using ELISA kits. RESULTS: IL-1beta, IL-6, IL-10, and TNF-alpha levels were found to be increased significantly in the inflammatory stage of Eales disease as compared to controls (p < .001). IL-1beta levels decreased significantly during the proliferative stage of the disease as compared to the inflammatory stage (p = .03). TNF-alpha levels increased significantly during the proliferative stage as compared to the inflammatory stage (p = .02). CONCLUSIONS: Raised levels of IL-1beta and TNF-alpha were observed in the inflammatory stage and persisted in the proliferative stage of the disease. The IL-1 system and TNF-alpha represent novel target for immunotherapy for controlling inflammatory activity and/or the associated long-term sequelae related to angiogenesis in Eales disease.

Interferon-beta and adhesion molecules (E-selectin and s-intracellular adhesion molecule-1) are detected in sera from patients with retinal vasculitis and are induced in retinal vascular endothelial cells by Toll-like receptor 3 signalling.

Retinal vasculitis is a major component of ocular inflammation that plays a role in retinal tissue damage in patients with idiopathic uveitis and Behçet's disease. Here we show that type 1 interferons (IFN alpha/beta) were not detected in sera from normal individuals but were identified in up to 46% of the sera from retinal vasculitis patients. The predominant form of IFN observed was IFN-beta, which was detected in 39% of Behçet's disease patients and 47% of idiopathic uveitis patients. Seven patients whose sera contained IFN-beta were monitored prospectively. IFN-beta was shown to be present for 6-12 months in all seven of the sera samples tested. Furthermore, the adhesion molecule profile identified in this study was strikingly different when Behçet's and uveitis patient sera were compared to sera from normal controls. Sera from Behçet's disease patients contained significantly elevated levels of the soluble adhesion molecules, sE-selectin and s-intracellular adhesion molecule-1 (sICAM-1), whereas sera from patients with idiopathic uveitis contained significantly increased sE-selectin. In vitro studies evaluating the cell source of these cytokines revealed that polyriboinosinic polyribocytidylic acid (poly I:C) activated retinal vascular endothelial cells produce sE-selectin, sICAM-1 and IFN-beta. Production of these molecules was inhibited by pretreatment with anti-Toll-like receptor 3 (TLR-3) antibody. In conclusion, IFN-beta, sE-selectin and sICAM-1 are elevated in patients with retinal vasculitis and are induced in retinal vascular endothelial cells in vitro by activating the innate immune system through TLR-3. Further analysis of innate immune signalling may prove to be a novel target for future studies on pathogenic mechanisms and therapeutic approaches in retinal vasculitis.