AMD Patients Research Articles

Chemokine Receptor Expression in Peripheral Blood Monocytes from Patients with Neovascular Age-Related Macular Degeneration

Chemokine signaling and monocytes/macrophages were implicated in the pathogenesis of AMD. We tested the association between chemokines involved in monocyte recruitment and AMD. Immunophenotyping for white blood cell (WBC) populations including CD14++CD16- and CD14+CD16+ monocytes, CD19+, CD3+, and CD16+ lymphocytes, and chemokine receptors CCR1, CCR2, CCR5, CX(3)CR1, and CXCR4 was performed on peripheral blood from treatment-naïve neovascular AMD (NV-AMD) patients and controls. The mRNA level of chemokine receptors in monocytes was measured with quantitative-PCR. Systemic levels of major chemokine ligands CCL2, CCL5, CCL3, and CXCL10 were evaluated by ELISA. Genotyping was performed for risk SNPs for AMD in the CFH, C3, and HTRA1 genes. The percentage of WBC subpopulations tested was similar between NV-AMD patients (n = 18) and controls (n = 20). CD14+CD16+ monocyte subpopulation showed a 3.5-fold increased expression of CCR1 (P = 0.039; t-test) and a 2.2-fold increased expression of CCR2 (P = 0.027) in patients compared with controls. Increased CCR1 and CCR2 expression was correlated with each other in patients (R(2) = 0.64, P < 0.0001), but not controls (R(2) = 0.02, P = 0.57). Increased mRNA levels of CCR1 (1.6-fold, P = 0.037) and CCR2 (1.6-fold, P = 0.007) were found in monocytes from NV-AMD patients. Chemokine receptor expression was not correlated with the presence of risk SNPs, and was not associated with blood chemokine levels. CCR1 and CCR2 are coupregulated on the CD14+CD16+ monocyte population in NV-AMD patients. These data implicate CD14+CD16+ monocytes and chemokine signaling in AMD. Additional investigation is needed to elucidate the role of these monocytes and their potential as a biomarker or therapeutic target for AMD.

Plasma taurine levels in age‐related macular degeneration

AbstractPurpose Taurine is one of the most abundant free amino acids in many tissues, including the retina. It is a scavenger of hypochlorite and carbonyl radicals and also inhibits lipid peroxidation. Little is know about the role of taurine in the pathogenesis of AMD. The purpose of this study was to determine the plasma levels of taurine in AMD patients and in age‐matched subjects without AMD.Methods Plasma taurine levels were measured by capillary electrophoresis in 74 AMD patients (mean age: 78±6.7 years) and in 148 controls (mean age: 77±5.3 years), all accrued in September 2011‐March 2012. Statistical analysis was performed using the Mann‐Whitney Rank Sum Test.Results Median taurine was 64.7 (range 28.6‐127.2) µmol/L in AMD patients and 65.8 (range 28.1‐132.3) µmol/L in controls. Statistical analysis showed no significant difference between the two groups.Conclusion Results suggest that AMD patients may have similar plasma levels of taurine as matched controls without AMD. Should these results be confirmed by larger studies, this would imply that taurine may play a marginal or no role in the pathogenesis of AMD.

Vascular endothelial growth factor A genetic polymorphisms and AMD in Tunisians

AbstractPurpose To determine whether vascular endothelial growth factor (VEGF) gene polymorphism plays a role in either susceptibility risk for exudative AMD, serum VEGF levels variations and treatment with intravitreal bevacizumab in TunisiansMethods In this case–control study, we included 96 patients with exudative AMD and 207 age‐matched controls treated with intravitreal bevacizumab. Single nucleotide polymorphism (SNP) genotyping was performed using restriction fragment length polymorphism (RFLP) analysis of polymerase chain reaction (PCR) products. The serum VEGF was assayed by ELISA (R&amp;D).Results The frequency of the VEGF ‐2578 A allele was significantly higher in AMD patients than in controls (p=0.005; OR: 2.12[1.23‐3.66]) and was statistically associated to higher serum levels of VEGF (93.30 pg/ml versus 39.75 pg/ml for C allele) (p: 0.021). When examining the effect of this polymorphism on post‐treatment visual acuities (VA), we observed that A variant allele was also statistically more prevalent among patients with better outcome for distance and reading visual acuity after three bevacizumab injections compared to those with loss of 3 or more lines in visual acuity (OR = 2.5, 95% CI [1.13‐5.73], p = 0.02). Furthermore, the mean of VEGF plasma level is significantly higher (170.97 pg/ml) in patients with enhanced VA compared to those with worse outcome for distance and reading visual acuity (45.52pg/ml) (p=0.003).Conclusion In addition to the higher risk for exudative AMD in Tunisian patients with the ‐2578 A VEGF, our results show that this allelic variant also correlates with better visual acuity outcome after treatment with bevacizumab probably through a functional or quantitative variation of plasma levels of this molecule.

Molecular pathology of inflammation in age‐related macular degeneration

AbstractPurpose To review molecular pathology of inflammation in age‐related macular degenerationMethods Personal and collaborative research in addition to literature reviewResults Risk for AMD is multifactorial, relating to age, environmental and genetic factors. Genome‐wide and targeted genetic association studies have identified various polymorphisms important for AMD susceptibility. Many are within immune‐related genes, including complement factors, e.g. CFH, C2, C3, CFB, and CFI; Toll‐like receptors, e.g., TLR‐3 and TLR‐4; and chemokines and receptors, e.g., CX3CR1 and CCR3. In addition, copy number variation/polymorphism, miRNA and epigenetics related to immune relevant genes could also contribute to AMD pathogenesis and patient responses to specific therapies. Inflammatory cells (mainly macrophages and microglia) and inflammatory factors (complement factors, cytokines/chemokines, oxidative stress‐related inflammatory products) are demonstrated in AMD lesions at various stages.Conclusion The molecular characterization of AMD captures the localizations and interactions among the inflammatory elements, relevant molecules (e.g., oxidative stress products and lipoprotein), and retinal/choroidal cells, in particular, the photoreceptors and RPE.

Retrospective analysis of the real‐world utilization of ranibizumab in wAMD

AbstractPurpose With monthly ranibizumab treatment for wet AMD (wAMD), optimal functional outcomes are achieved. To reduce management burdens, as‐needed dosing regimens have been explored. AURA study examines real‐world utilization of ranibizumab.Methods Retrospective, international (Canada, France, Germany, Ireland, Italy, Netherlands, UK, Venezuela), non‐interventional, observational study. Target enrollment is 444 patients per country and will be completed by September 2012. Consecutive AMD patients prescribed ranibizumab by their physicians will be included, with a follow‐up period of up to 2.5 years. Primary outcomes are (1) change in visual acuity and (2) resource utilization (number of treatment and monitoring visits, treatment use). Descriptive statistics will be used.Results Results for Germany are already available: 916 patients from 28 sites were screened. Of these, 462 (50.4%) were not enrolled. The reasons (not mutually exclusive) included no written informed consent (n=349), consent obtained after target patient number reached (n=68), use of non‐conventional interventions (n=21), ranibizumab use did not start between January‐August 2009 (n=23), and no wAMD diagnosis (n=6). Of the 454 enrolled, 437 (96.3%) received ≥1 ranibizumab dose. Of the 437, most were women (n=260, 59.5%), Caucasian (n=368, 84.2%), and initiated treatment at ≥75 years of age (n=304, 69.6%). Mean age was 79.2±8.1 years.Conclusion These data will provide valuable insight into resource utilization patterns and their effects on visual outcome in various ranibizumab‐treated wAMD patient populations. Commercial interest

Assessment of the spectralis spectral domain oct segmentation software in a retrospective cohort study of exudative amd patients

AbstractPurpose To assess the ability of the Spectralis optical coherence tomography (OCT) segmentation software to identify the inner limiting membrane and the Bruch’s membrane in exudative AMD patients.Methods Thirty‐eight eyes of 38 naive exudative AMD patients were retrospectively included. They all had a complete ophthalmologic examination including Spectralis OCT at baseline, at month‐1 and at month‐2. Reliability of the segmentation software was was defined as good if both inner limiting membrane and Bruch’s membrane were correctly drawn.Results A total of 38 patients charts were reviewed (114 scans). The inner limiting membrane was correctly drawn in 114/114 SD‐OCT scans (100 %). Conversely, the Bruch’s membrane was correctly drawn in 59/114 scans (51.8 %). The software was less reliable in locating the Bruch’s membrane in case of pigment epithelium detachment (PED) than without PED (42.5% vs 73.5 % respectively, p =0.049).Conclusion Segmentation of inner limiting membrane was constantly trustworthy but Bruch’s membrane segmentation was poorly reliable using the automatic SD‐OCT Spectralis segmentation software. Based on this software, evaluation of retinal thickness may be incorrect, particularly in case of PED.

Short- and mid-term repeatability of macular pigment optical density measurements using spectral fundus reflectance

Several methods have been proposed for measuring macular pigment optical density (MPOD). To date, none of the realized techniques can be considered as "gold standard". A key issue for the clinical applicability of a method is its repeatability. In this study, we investigated short- and mid-term repeatability of MPOD measurements using reflectometry. A total of 12 healthy young subjects were measured 5 times on 5 consecutive days. Repeatability over 6 months was investigated in patients with AMD. The data in AMD patients were taken from a recently published placebo controlled study investigating the effect of lutein supplementation on MPOD (n = 37; [1]). Four measurements over 6 months were used to calculate repeatability. Spectral fundus reflectance of the fovea was measured in a 2.3° detection field with a custom-built fundus reflectometer. Calculation of MPOD was based on a previously published fundus reflectance model. The coefficients of variation were 6.2 ± 2.4% and 8.0 ± 5.5% in the healthy and AMD group, respectively. Bland-Altman plots indicate that the difference between measurements at day 1 and day 5 in healthy subjects and day 1 and month 6 in AMD patients was small. The maximum deviation in MPOD in a healthy subject was 0.07 (22.6%), and 0.17 (51.5%) in a patient with AMD. Reflectometry provides adequate short-term and mid-term repeatability for measuring MPOD. Accordingly, the technique makes it possible to monitor MPOD in patients with AMD and to study the influence of supplementation in these subjects. In addition, the variability of the technique is small enough to allow for clinical trials with reasonable sample size.

Genetic polymorphism of the iron-regulatory protein-1 and -2 genes in age-related macular degeneration

Iron can be involved in the pathogenesis of AMD through the oxidative stress because it may catalyze the Haber–Weiss and Fenton reactions converting hydrogen peroxide to free radicals, which can induce cellular damage. We hypothesized that genetic polymorphism in genes related to iron metabolism may predispose individuals to the development of AMD and therefore we checked for an association between the g.32373708 G>A polymorphism (rs867469) of the IRP1 gene and the g.49520870 G>A (rs17483548) polymorphism of the IRP2 gene and AMD risk as well as the modulation of this association by some environmental and life-style factors. Genotypes were determined in DNA from blood of 269 AMD patients and 116 controls by the allele-specific oligonucleotide-restriction fragment length polymorphism and the polymerase chain reaction-restriction fragment length polymorphism. An association between AMD, dry and wet forms of AMD and the G/G genotype of the g.32373708 G>A-IRP1 polymorphism was found (OR 3.40, 4.15, and 2.75). On the other hand, the G/A genotype reduced the risk of AMD as well as its dry or wet form (OR 0.23, 0.21, 0.26). Moreover, the G allele of the g.49520870 G>A-IRP2 polymorphism increased the risk of the dry form of the disease (OR 1.51) and the A/A genotype and the A allele decreased such risk (OR 0.43 and 0.66). Our data suggest that the g.32373708 G>A-IRP1 and g.49520870 G>A-IRP2 polymorphisms may be associated with increased risk for AMD.

Response to ‘Combined OCT and colour fundus photography in virtual clinic assessments of wet AMD patients’

Response to ‘Combined OCT and colour fundus photography in virtual clinic assessments of wet AMD patients’

Combined OCT and colour fundus photography in virtual clinic assessments of wet AMD patients

Combined OCT and colour fundus photography in virtual clinic assessments of wet AMD patients

Predictive Factors in OCT Analysis for Visual Outcome in Exudative AMD.

Background. Reliable predictive factors for therapy outcome may enable treating physicians to counsel their patients more efficiently concerning probability of improvement or time point of discontinuation of a certain therapy. Methods. This is a retrospective analysis of 87 patients with exudative age-related macular degeneration who received three monthly intravitreal ranibizumab injections. Visual acuity before initiation of intravitreal therapy and 4–6 weeks after last intravitreal injection was compared and related to the preoperative visualisation of continuity of the outer retinal layers as assessed by OCT: external limiting membrane (ELM), inner photoreceptor segments (IPS), junction between inner and outer segments (IS/OS), and outer photoreceptor segments (OPS). Results. Visual acuity increased in 40 of 87 (46.0%) patients, it remained stable in 25 (28.7%), and 22 (25.3%) patients had decreased visual acuity four to six weeks after triple intravitreal ranibizumab injections. No statistically significant predictive value could be demonstrated for grade of continuity of outer retinal layers concerning visual acuity development. Conclusions. In our series of AMD patients, grade of continuity of outer retinal layers was not a significant predictive value for visual acuity development after triple ranibizumab injections.

Residual abilities in age-related macular degeneration to process spatial frequencies during natural scene categorization

Age-related macular degeneration (AMD) is characterized by a central vision loss. We explored the relationship between the retinal lesions in AMD patients and the processing of spatial frequencies in natural scene categorization. Since the lesion on the retina is central, we expected preservation of low spatial frequency (LSF) processing and the impairment of high spatial frequency (HSF) processing. We conducted two experiments that differed in the set of scene stimuli used and their exposure duration. Twelve AMD patients and 12 healthy age-matched participants in Experiment 1 and 10 different AMD patients and 10 healthy age-matched participants in Experiment 2 performed categorization tasks of natural scenes (Indoors vs. Outdoors) filtered in LSF and HSF. Experiment 1 revealed that AMD patients made more no-responses to categorize HSF than LSF scenes, irrespective of the scene category. In addition, AMD patients had longer reaction times to categorize HSF than LSF scenes only for indoors. Healthy participants' performance was not differentially affected by spatial frequency content of the scenes. In Experiment 2, AMD patients demonstrated the same pattern of errors as in Experiment 1. Furthermore, AMD patients had longer reaction times to categorize HSF than LSF scenes, irrespective of the scene category. Again, spatial frequency processing was equivalent for healthy participants. The present findings point to a specific deficit in the processing of HSF information contained in photographs of natural scenes in AMD patients. The processing of LSF information is relatively preserved. Moreover, the fact that the deficit is more important when categorizing HSF indoors, may lead to new perspectives for rehabilitation procedures in AMD.

Adaptive optics imaging in age‐related macular degeneration

AbstractPurpose To document cases of drusen and age‐related geographic atrophy(GA) at the microscopic scale using adaptive optics(AO).Methods Four cases of age‐related drusens, 2 cases of familial drusen and 7 patients of GA underwent en face retinal imaging by AO retinal camera(rtx1, Imagine Eyes, Orsay, France). AO images were confronted to high‐resolution spectral‐domain optical coherence tomography(OCT) and scanning laser ophthalmoscopy(SLO) examinations.Results In AO images, most drusen appeared as doughnut‐shaped highly reflective zones, and were better delineated than by color fundus photograph. The overlying cone mosaic could be detected over most of them, including their top. Between drusen, the cone photoreceptor mosaic appeared normal. In GA cases, AO images revealed irregular patches of multiple cone‐like bright spots as well as larger dark disks in atrophic areas.Conclusion AO provided images of microscopic structures in various types of AMD, including GA. Local losses in cone contrast at the drusen slopes confirmed a strong relation between cone visibility and their orientation. There was no evidence of cone loss in association to drusen. In GA patients, our findings suggest that photoreceptors with shortened outer segments may survive within atrophic areas, which may lead to the development of novel therapeutic strategies aimed at restoring the function of surviving cones. These results demonstrate that AO retinal camera can detect isolated residual photoreceptors, and hence that it will be a powerful tool for quantifying spontaneous or therapeutic changes in AMD patients. Supported by ANR through Tecsan Program (project iPhot n° ANR‐09‐TECS‐009)

Retinal blood flow in response to an intravitreal injection of ranibizumab for neovascular age‐related macular degeneration

To assess the hemodynamic response of retinal arterioles and venules following a single intravitreal injection of ranibizumab in neovascular age-related macular degeneration (NV-AMD) patients and to assess the influence of the number of prior injections on this response. Fifteen NV-AMD patients were prospectively recruited and grouped according to the dosage of ranibizumab previously received. Group 1 NV-AMD patients (n = 7) had previously received 1.50 mg or less, and group 2 patients (n = 8) had received more than 1.50 mg in the study eye. A group of 12 non-NV AMD patients were also recruited for control comparison. Vessel diameter, centreline blood velocity and blood flow were assessed with the Canon Laser Blood Flowmeter immediately prior to an injection and at a mean follow-up of 37.7 and 36.7 days for group 1 and group 2 patients, respectively. The NV-AMD patients as a whole and the group 1 cohort had a significantly greater arteriolar diameter at baseline than the non-NV AMD patients. There was a significant reduction in arteriolar diameter, velocity and blood flow in group 1 but not in group 2 NV-AMD patients at follow-up. There was only an insignificant decrease in measured parameters of the retinal venules. At follow-up, there was no difference in the diameter, velocity or flow between AMD patients. Intravitreal ranibizumab treatment for NV-AMD induces a reduction in arteriolar diameter, velocity, and blood flow in patients who have received <1.50 mg of ranibizumab.

Use of different PRL strategies during reading with AMD patients

Use of different PRL strategies during reading with AMD patients

SCANNING LASER OPHTHALMOSCOPE IMAGING STABILIZED MICROPERIMETRY IN DRY AGE-RELATED MACULAR DEGENERATION

To determine the effect of drusen and geographic atrophy (GA) in dry age-related macular degeneration on retinal sensitivity using an eye tracking scanning laser ophthalmoscope microperimetry. A total of 44 eyes from 22 patients with dry age-related macular degeneration and drusen and 11 patients with GA were imaged with scanning laser ophthalmoscope microperimetry (OPKO Health, Miami, FL). A custom microperimetry pattern was used to evaluate retinal sensitivity to a Goldmann III size target (108 μm on the retina). The perimetry used a 4-2 stepladder algorithm to determine maximal sensitivity. Microperimetry and optical coherence tomography were performed using a standardized protocol. Twenty-eight eyes with drusen and 16 eyes with GA were analyzed. Retinal sensitivity overlying drusen was significantly reduced compared with the adjacent uninvolved retina. There was a significant correlation between retinal sensitivity and drusen volume, as well as the grading of the photoreceptor inner segment/outer segment junction score. In patients with GA, an absolute scotoma was confirmed. Retinal sensitivity at the margin of GA was significantly decreased compared with the adjacent uninvolved retina. Scanning laser ophthalmoscope microperimetry is able to detect changes in retinal sensitivity in AMD patients overlying drusen and at the margin of GA. It is a useful device to grade focal retinal sensitivity in patients with dry age-related macular degeneration.

Carboxyethylpyrrole plasma biomarkers in age-related macular degeneration

Age-related macular degeneration causes irreversible central blindness in people over the age of 50 and is increasing in prevalence among elderly populations. There are currently limited treatment options available for the exudative form of the disease and no formal treatments for the geographic atrophy form aside from lifestyle change and incorporation of antioxidant supplements in the diet. As such, it is important to be able to assess high-risk AMD patients as early as possible in order to prescribe preventative measures. Carboxyethylpyrrole (CEP) is a promising plasma biomarker suited to this purpose. Both CEP immunoreactivity levels as well as anti-CEP autoantibody titers are significantly elevated in AMD patients and thus provide the potential to assess AMD susceptibility with approximately 80% accuracy when evaluated alongside genomic AMD markers. Moreover, strong evidence implicates CEP as functionally related to AMD pathogenesis, a role which must be explored further. This avenue of research will foster improved understanding of the disease itself and perhaps reveal better therapeutic targets and options. Further research into the role of CEP in AMD pathogenesis and the application of CEP as an AMD biomarker is merited.

C3 gene polymorphism R102G in a Greek population with age‐related macular degeneration

Abstract Purpose To elucidate whether C3 R102G polymorphism is a major genetic determinant of AMD in a Greek population as well as to evaluate its prognostic importance for progression to advanced AMD Methods A clinic‐based case‐control association study was conducted, comprising 98 Greek patients with early‐ and advanced‐stage AMD and 125 independent controls of Caucasian origin. All participants underwent a complete ophthalmic examination, fluorescein angiography and OCT. Information on cigarette smoking, hypertension and family history was obtained by interview at baseline. Moreover, they were genotyped for C3 R102G polymorphism, by using ARMS‐PCR. Results The frequency of the C3 R102G allele was significantly higher in AMD patients in comparison with controls while the odds ratio (OR) for AMD was 1,46 (CI 95% = 0,82‐2,59). Statistical comparison between early and advanced AMD patients, on the basis of C3 genotypic frequencies, revealed that the C3 R102G allele was more prevalent in advanced AMD patients (P&lt;0,05, OR=2,62). Moreover, both GG and CG genotypes were found to be more prevalent in patients with neovascular AMD (ORs = 3,95 and 2,51, respectively) when compared with non‐exudative AMD patients. Concerning family history, it is significantly higher among patients with GG genotype when compared to CG and CC genotypes. On the contrary, C allele was associated with hypertension and smoking in AMD patients when compared to G allele. Conclusion The replication of the reported associations of C3 R102G polymorphism with AMD suggest that the 102G allele could serve as a genetic marker for the development of AMD and the progression of the disease to the advanced clinical stage in the Greek population.

Scene perception in macular degeneration: the effect of contrast

Abstract Purpose To access performance of AMD patients in an animal/non‐animal categorization task using achromatic natural scenes with large reductions in contrast, and to study the relation between visual acuity, lesion size and the performance of categorization. Methods Eighteen patients with neovascular AMD and visual acuity less than 20/50 were included. Seventeen age‐matched healthy subjects were used as controls. Complete ophthalmologic examination were performed in all participants. The stimuli were photographs of animal (targets) and natural scenes (distractors) , displayed on a screen, with four level of contrast N, N/2, N/4 and N/8. Participants were asked to press a key when they saw an animal. Accuracy, false alarms, correct rejections were recorded. Results Percentage of correct detections was lower in AMD patients compared to control. Larger decrease of performance was observed in AMD patients than in controls when the contrast condition was reduced. No correlation was found between performance and lesion size. Correlation was found between visual acuity and performance when contrast level was reduced to N/2, N/4 and N/8. Conclusion The results of the present study may be considered for adaptation of luminance and contrast in the environment of AMD subjects, in order to improve to improve their mobility and to prevent falls.

Lutein supplementation and spatial vision in early AMD

Abstract Purpose To investigate the effect on spatial vision of enhancing macular pigment (MP) with lutein (L) capsules in patients with early AMD. Methods A randomised, placebo‐controlled two‐centred, 12 months study of the effects of L supplementation was conducted in Manchester, UK and Maastricht, The Netherlands. L capsules (10mg Ester), or a placebo were taken daily. 35 patients (mean age 73.4 ± 8.2, VA&gt;0.5 logMar) were randomly assigned to either L (lutein, n=19) or P (placebo, n=16) groups. Best corrected Log MAR visual acuities, contrast sensitivities (CS) at 0.5, 2, 4, 8,12 and 16 c/deg, and MP were measured at baseline and on three, four month intervals, after the start of the 12 month supplementation period. MP was measured using a flicker‐based technique. Results An increase in the mean MP levels was found for the L group; from 0.35±0.19 to 0.47±0.22 OD units that was statistically significant (p&lt;0.0003) while no change in MP was found for the P group. A mean improvement from 0.23±0.12 (baseline) to 0.16±0.10 (visit 4) was found in the VA of the L group (statistically significant, p= 0.004). In the P group there was a non‐significant deterioration in VA from 0.18±0.12 to 0.20±0.12. The mean difference in VA between baseline and visit 4 for the L group was 0.07±0.10 and for the P group was ‐0.03±0.10 (statistically significant difference, p= 0.004). No statistically significant changes were found in CS at any of the tested spatial frequencies for either of the 2 groups. Conclusion Lutein supplementation over a 12 months period improves MP levels in AMD patients and this corresponds to an overall improvement in VA. No such effect is observed in CS.