Increased pro-MMP9 plasma levels are associated with neovascular age-related macular degeneration and with the risk allele of rs142450006 near MMP9.

Purpose: To evaluate the plasma levels of matrix metalloproteinase 9 (MMP9) and tissue inhibitors of metalloproteinase 3 (TIMP3) in neovascular age-related macular degeneration (nAMD) patients compared to controls, and to explore the potential effect of AMD-associated genetic variants on MMP9 and TIMP3 protein levels. Methods: nAMD and control patients were selected from the European Genetic Database (EUGENDA) based on different genotypes of rs142450006 near MMP9 and rs5754227 near TIMP3. Plasma total MMP9, active MMP9 and TIMP3 levels were measured using the enzyme linked immunosorbent assay (ELISA) and compared between nAMD patients and controls, as well as between different genotype groups. Results: nAMD patients had significantly higher total MMP9 levels compared to controls (median 46.58 versus 26.90 ng/ml; p = 0.0004). In addition, the median MMP9 level in the homozygous genotype group for the AMD-risk allele (44.23 ng/ml) was significantly higher than the median for the heterozygous genotype group (26.90 ng/ml; p = 0.0082) and the median for the homozygous group for the non-risk allele (28.55 ng/ml; p = 0.0355). No differences were detected for the active MMP9. TIMP3 levels did not significantly differ between the AMD and control groups, nor between the different genotype groups for rs5754227. Conclusions: The results of our MMP9 analyses indicate that nAMD patients have on average higher systemic MMP9 levels than control individuals, and that this is partly driven by the rs142450006 variant near MMP9. This finding might be an interesting starting point for further exploration of MMP9 as a therapeutic target in nAMD, particularly among individuals carrying the risk-conferring allele rs142450006.

Evaluation pro/antioxidant balance in patients with wet form of age-related macular degeneration. / [Ocena równowagi proantyoksydacyjnej u chorych na wysiekowa postac zwyrodnienia plamki zwiazanego z wiekiem].

Objective: The aim of study was to evaluate the ability of the enzymatic antioxidant barrier to protect against peroxidation in patients with wet age-related macular degeneration, as compared to healthy subjects. Material and methods: Hemolysate blood samples collected from 25 patients with wet form age-related macular degeneration and 25 healthy controls were analysed to determine the activity of superoxide dismutase (using Misra and Fridovich method), catalase (using Beers and Sizer method), glutathione peroxidase (using Sedlak and Lindsay method modified by Little and O'Brien), and malondialdehyde concentration (using Placer method). Results: We observed a statistically significant decrease in the activity of following enzymes in patients with wet age-related macular degeneration, as compared to controls: superoxide dismutase (2086.3 vs. 2348.5 U/gHb/100 ml; p ≤ .05), catalase (6.9 vs. 7.6 BU/gHb, p ≤ .05) and glutathione peroxidase (36.3 vs. 45.8 U/gHb; p ≤ .05). At the same time, an increase in age-related macular degeneration thiobarbituric acid reactive substance concentration was demonstrated in patients with wet age-related macular degeneration, as compared to healthy subjects (.119 vs. .286 µmol/gHb; p ≤ .001). Conclusion: The obtained results indicate inefficient enzymatic antioxidant system which manifests as intense peroxidation in patients with age-related macular degeneration.

Expression of SIRT1 in choroidal neovascular membranes.

PURPOSE: SIRT1 is a deacetylase that has been shown to be instrumental in embryonic and pathologic vascular formation. The purpose of this study was to evaluate the potential role of SIRT1 in the pathogenesis of choroidal neovascularization in age-related macular degeneration. METHODS: The expression of SIRT1 was assessed via immunohistochemistry in nine excised human choroidal neovascularization membranes and seven non-age-related macular degeneration donor eyes. Enzyme-linked immunosorbent assay-based angiogenesis arrays were used to assess the potential of an SIRT1 inhibitor, nicotinamide, to reduce secretion of 10 unique proangiogenic cytokines from retinal pigment epithelial cells. RESULTS: SIRT1 was expressed more frequently in choroidal neovascularization membranes than donor eyes about vascular endothelial cells (78 vs. 29% positive cases) and retinal pigment epithelial cells (57 vs. 14% positive cases). SIRT1 inhibition in retinal pigment epithelial cells correlated with significantly decreased secretion of three potent proangiogenic cytokines: angiogenin, platelet-derived growth factor BB, and vascular endothelial growth factor A. CONCLUSION: SIRT1 levels appear elevated in human choroidal neovascularization membranes compared with control eyes. Moreover, inhibition of SIRT1 activity is correlated with decreased secretion of potent proangiogenic cytokines. Collectively, these data support a potential role for SIRT1 in the pathogenesis of neovascular age-related macular degeneration.

Association of glutathione S-transferase pi isoform single-nucleotide polymorphisms with exudative age-related macular degeneration in a Chinese population.

PURPOSE: To investigate the association between single-nucleotide polymorphisms in the pi isoform of glutathione S-transferase (GSTP1) gene and the risk of exudative age-related macular degeneration (AMD) in a Chinese case-control cohort. METHODS: A total of 131 Chinese patients with exudative AMD and 138 control individuals were recruited. Genomic DNA was extracted from venous blood leukocytes. Two common nonsynonymous single-nucleotide polymorphisms in GSTP1 (rs1695 and rs1138272) were genotyped by polymerase chain reaction followed by allele-specific restriction enzyme digestion and direct sequencing. RESULTS: Significant association with exudative AMD was detected for single-nucleotide polymorphism, rs1695 (P = 0.019). The risk G allele frequencies were 21.8% in AMD patients and 12.7% in control subjects (P = 0.007). Compared with the wild-type AA genotype, odds ratio for the risk of AMD was 1.91 (95% confidence interval, 1.09-3.35) for the heterozygous AG genotype and 2.52 (95% confidence interval, 0.6-10.61) for the homozygous GG genotype. In contrast, rs1138272 was not associated with exudative AMD (P = 1.00). The risk G allele frequencies of rs1138272 were 0.4% in AMD patients and 0.4% in control subjects (P = 1.00). CONCLUSION: Our data suggest that the GSTP1 variant rs1695 moderately increases the risk of exudative AMD. The variant rs1138272 was rare and was not associated with exudative AMD in this Chinese cohort.

Impact of methylenetetrahydrofolate reductase C677T polymorphism on the efficacy of photodynamic therapy in patients with neovascular age-related macular degeneration.

The most severe visual impairments due to age-related macular degeneration (AMD) are frequently caused by the occurrence of choroidal neovascularization (CNV). Although photodynamic therapy with verteporfin (PDT-V) is currently a second-line treatment for neovascular AMD, it can be conveniently combined with drugs acting against vascular endothelial growth factor (anti-VEGF) to reduce the healthcare burden associated with the growing necessity of anti-VEGF intravitreal re-injection. Because the common 677 C > T polymorphism of the methylenetetrahydrofolate reductase gene (MTHFR-C677T; rs1801133) has been described as predictor of satisfactory short-term responsiveness of AMD-related CNV to PDT-V, we retrospectively examined the outcomes of 371 Caucasian patients treated with standardized, pro-re-nata, photodynamic regimen for 24 months. Responder (R) and non-responder (NR) patients were distinguished on the basis of the total number of scheduled PDT-V (TN-PDT-V) and change of best-corrected visual acuity (∆-BCVA). The risk for both TN-PDT-V and ∆-BCVA to pass from R to NR group was strongly correlated with CT and TT genotypes of MTHFR-C677T variant resulting, respectively, in odd ratios of 0.19 [95% CI, 0.12-0.32] and 0.09 [95% CI, 0.04-0.21] (P < 0.001), and odd ratios of 0.24 [95% CI, 0.15-0.39] and 0.03 [95% CI, 0.01-0.11] (P < 0.001). These pharmacogenetic findings indicate a rational basis to optimize the future clinical application of PDT-V during the combined treatments of AMD-related CNV, highlighting the role of thrombophilia to be aware of the efficacy profile of photodynamic therapy.

The role of proteases and inflammatory molecules in triggering neovascular age-related macular degeneration: basic science to clinical relevance.

Age-related macular degeneration (AMD) causes severe vision impairment in aged individuals. The health impact and cost of the disease will dramatically increase over the years, with the increase in the aging population. Currently, antivascular endothelial growth factor agents are routinely used for managing late-stage AMD, and recent data have shown that up to 15%-33% of patients do not respond to this treatment. Henceforth, there is a need to develop better treatment options. One avenue is to investigate the role proteases and inflammatory molecules might have in regulating and being regulated by vascular endothelial growth factor. Moreover, emerging data indicate that proteases and inflammatory molecules might be critical in the development and progression of AMD. This article reviews recent literature that investigates proteases and inflammatory molecules involved in the development of AMD. Gaining insights into the proteolytic and inflammatory pathways associated with the pathophysiology of AMD could enable the development of additional or alternative drug strategies for the treatment of AMD.