Clinical update: new treatments for age-related macular degeneration

Stereotactic radiotherapy for wet age-related macular degeneration: current perspectives

Neovascular age-related macular degeneration is a leading cause of blindness in the developed world. Currently, the treatment of choice is intravitreal injections of anti-VEGF medications. These require frequent dosing, up to monthly, and impose a substantial burden on patients and the health economy. Ionizing radiation was proposed as a possible treatment for age-related macular degeneration due to its anti-inflammatory and anti-fibrotic properties. Stereotactic radiotherapy is an outpatient-based radiotherapy platform that provides stereotactic application of low energy X-ray to the retina in three highly collimated beams that cross the inferior sclera to overlap at the macula. A randomized, double-masked, sham-controlled trial of 230 patients (INTREPID) showed that a single dose of stereotactic radiotherapy significantly reduces the number of intravitreal anti-VEGF injections needed over 2 years. A larger randomized controlled trial (STAR) is underway.

Incidence of Late-Stage Age-Related Macular Degeneration in American Whites: Systematic Review and Meta-analysis

PURPOSE

To estimate incidence of age-related macular degeneration (AMD) by subtype in American whites aged ≥50 years.

DESIGN

Systematic review and meta-analysis.

METHODS

SETTING

Prospective cohort studies of AMD incidence in populations of white European ancestry published in MEDLINE, EMBASE, and Web of Science.

STUDY POPULATION

Fourteen publications in 10 populations that examined AMD incident cases were identified.

OBSERVATION PROCEDURE

Data on age-sex-specific incidence of late AMD, geographic atrophy (GA) and neovascular AMD (NVAMD), year of recruitment, AMD grading method, and continent were extracted.

MAIN OUTCOME MEASURE(S)

Annual incidence of late AMD, GA, and NVAMD by age-sex in American whites aged ≥50 years from a Bayesian meta-analysis of incidence studies was compared with incidence extrapolated from published prevalence estimates.

RESULTS

Incidence rates from the review agreed with those derived from prevalence, but the latter were based on more data, especially at older ages and by AMD subtypes. Annual incidence (estimated from prevalence) of late AMD in American whites was 3.5 per 1000 aged ≥50 years (95% credible interval 2.5, 4.7 per 1000), equivalent to 293 000 new cases in American whites per year (95% credible interval 207 000, 400 000). Incidence rates approximately quadrupled per decade in age. Annual incidence GA rates were 1.9 per 1000 aged ≥50 years, NVAMD rates were 1.8 per 1000. Late AMD incidence was 38% higher in women vs men (95% credible interval 6%, 82%).

CONCLUSIONS

Estimating AMD incidence from prevalence allows better characterization at older ages and by AMD subtype where longitudinal data from incidence studies are limited.

Facilitated Tau Degradation by USP14 Aptamers via Enhanced Proteasome Activity

The ubiquitin-proteasome system (UPS) is the primary mechanism by which intracellular proteins, transcription factors, and many proteotoxic proteins with aggregation-prone structures are degraded. The UPS is reportedly downregulated in various neurodegenerative disorders, with increased proteasome activity shown to be beneficial in many related disease models. Proteasomes function under tonic inhibitory conditions, possibly via the ubiquitin chain-trimming function of USP14, a proteasome-associated deubiquitinating enzyme (DUB). We identified three specific RNA aptamers of USP14 (USP14-1, USP14-2, and USP14-3) that inhibited its deubiquitinating activity. The nucleotide sequences of these non-cytotoxic USP14 aptamers contained conserved GGAGG motifs, with G-rich regions upstream, and similar secondary structures. They efficiently elevated proteasomal activity, as determined by the increased degradation of small fluorogenic peptide substrates and physiological polyubiquitinated Sic1 proteins. Additionally, proteasomal degradation of tau proteins was facilitated in the presence of the UPS14 aptamers in vitro. Our results indicate that these novel inhibitory UPS14 aptamers can be used to enhance proteasome activity, and to facilitate the degradation of proteotoxic proteins, thereby protecting cells from various neurodegenerative stressors.

Role of periostin and its antagonist PNDA-3 in gastric cancer metastasis

The extracellular matrix component periostin is a secreted protein that functions as both a cell attachment protein and an autocrine or paracrine factor that signals through the cell adhesion molecule integrins α_vβ₃ and α_vβ₅. Periostin participates in normal physiological activities such as cardiac development, but is also involved in pathophysiological processes in vascular diseases, wound repair, bone formation, and tumor development. It is of increasing interest in tumor biology because it is frequently overexpressed in a variety of epithelial carcinomas and is functionally involved in multiple steps of metastasis progression. These include the maintenance of stemness, niche formation, EMT, the survival of tumor cells, and angiogenesis, all of which are indispensable for gastric cancer metastasis. Periostin has been reported to activate the PI-3K/AKT, Wnt, and FAK-mediated signaling pathways to promote metastasis. Therefore, periostin represents a potentially promising candidate for the inhibition of metastasis. In this review article, we summarize recent advances in knowledge concerning periostin, its antagonist PNDA-3, and their influence on such key processes in cancer metastasis as maintenance of stemness, niche formation, epithelial-to-mesenchymal transition, tumor cell survival, and angiogenesis. In particular, we focus our attention on the role of periostin in gastric cancer metastasis, speculate as to the usefulness of periostin as a therapeutic and diagnostic target for gastric cancer metastasis, and consider potential avenues for future research.

Gene Therapy with Endogenous Inhibitors of Angiogenesis for Neovascular Age-Related Macular Degeneration: Beyond Anti-VEGF Therapy

Age-related macular degeneration (AMD) is the leading cause of substantial and irreversible vision loss amongst elderly populations in industrialized countries. The advanced neovascular (or “wet”) form of the disease is responsible for severe and aggressive loss of central vision. Current treatments aim to seal off leaky blood vessels via laser therapy or to suppress vessel leakage and neovascular growth through intraocular injections of antibodies that target vascular endothelial growth factor (VEGF). However, the long-term success of anti-VEGF therapy can be hampered by limitations such as low or variable efficacy, high frequency of administration (usually monthly), potentially serious side effects, and, most importantly, loss of efficacy with prolonged treatment. Gene transfer of endogenous antiangiogenic proteins is an alternative approach that has the potential to provide long-term suppression of neovascularization and/or excessive vascular leakage in the eye. Preclinical studies of gene transfer in a large animal model have provided impressive preliminary results with a number of transgenes. In addition, a clinical trial in patients suffering from advanced neovascular AMD has provided proof-of-concept for successful gene transfer. In this mini review, we summarize current theories pertaining to the application of gene therapy for neovascular AMD and the potential benefits when used in conjunction with endogenous antiangiogenic proteins.

Incidence of myocardial infarction, stroke, and death in patients with age-related macular degeneration treated with intravitreal anti-vascular endothelial growth factor therapy

PURPOSE

To describe the rates of myocardial infarction (MI), stroke, and mortality in patients who have treatment with intravitreal anti-vascular endothelial growth factor (anti-VEGF) injections for age-related macular degeneration (AMD).

DESIGN

A retrospective population linkage study.

METHOD

We identified patients aged 40 years and above who received treatment with intravitreal anti-VEGF injections for AMD from January 1, 2008 to December 31, 2011 at the Singapore National Eye Centre. We used a national record linkage database to identify patients who developed MI, stroke, and all-cause mortality after the first injection, excluding those with previous MI or stroke at baseline from the respective analysis. We compared rates of MI, stroke, and mortality to that of the total Singapore population.

RESULTS

A total of 1182 individuals had an intravitreal anti-VEGF injection included in this analysis, with the majority receiving bevacizumab (n = 1011). Overall, 19 patients developed MI, 16 developed stroke, and there were 43 mortalities, giving an age-adjusted incidence rate of 350.2 per 100 000 person-years for MI, 299.3 per 100 000 person-years for stroke, and 778.9 per 100 000 person-years for mortality. This is comparable to the weighted incidence rates of the Singapore population (427.1 per 100 000 person-years for MI, 340.4 per 100 000 person-years for stroke, and 921.3 per 100 000 person-years for mortality).

CONCLUSION

The incidence rate of MI, stroke, and death in this cohort of AMD patients treated with anti-VEGF was low, and was not significantly higher than the age-adjusted incidence rate of these events in the Singapore population.

Population-based age group specific annual incidence rates of symptomatic age-related macular degeneration

Purpose

To study the population-based annual incidence rates of exudative, dry and all cases of symptomatic age-related macular degeneration (AMD) in different age and sex groups.

Methods.

This is a one year, prospective, population-based study on all consecutive new patients with AMD in the hospital district of Central Finland. The diagnosis was confirmed in all patients with slit lamp biomicroscopy, optical coherence tomography (OCT) using a Spectralis HRA + OCT device, and the Heidelberg Eye Explorer 1.6.2.0 program. Fluorescein angiograms were taken when needed.

Results.

The population-based annual incidence rates of all cases of symptomatic AMD increased from 0.03% (95% CI, 0.01-0.05%) in the age group 50-59 years to 0.82% (95% CI, 0.55-1.09%) in the age group 85-89 years and were 0.2% (95% CI, 0.17-0.24%) in exudative, 0.11% (95% CI, 0.09-0.14%) in dry, and 0.32% (95% CI, 0.28-0.36%) in all cases of AMD in the age group 60 years and older. During the next 20 years in Central Finland the population-based annual incidence rates can be estimated to increase to 0.27% (95% CI, 0.24-0.30%) in exudative, to 0.13% (95% CI, 0.11-0.15%) in dry, and to 0.41% (95% CI, 0.37-0.45%) in all cases of AMD in the age group 60 years and older. The population-based annual incidence of AMD did not show statistically significant differences between males and females (p>0.1).

Conclusion:

The population-based age-group specific annual incidence rates of symptomatic AMD of this study may help to plan health care provision for patients of AMD.

Osteopontin mediates an MZF1-TGF-β1-dependent transformation of mesenchymal stem cells into cancer-associated fibroblasts in breast cancer

Interactions between tumor cells and cancer-associated fibroblasts (CAFs) in the tumor microenvironment (TMEN) significantly influence cancer growth and metastasis. Transforming growth factor-β (TGF-β) is known to be a critical mediator of the CAF phenotype, and osteopontin (OPN) expression in tumors is associated with more aggressive phenotypes and poor patient outcomes. The potential link between these two pathways has not been previously addressed. Utilizing in vitro studies using human mesenchymal stem cells (MSCs) and MDA-MB231 (OPN+) and MCF7 (OPN−) human breast cancer cell lines, we demonstrate that OPN induces integrin-dependent MSC expression of TGF-β1 to mediate adoption of the CAF phenotype. This OPN-TGF-β1 pathway requires the transcription factor, myeloid zinc finger 1 (MZF1). In vivo studies with xenotransplant models in NOD-scid mice showed that OPN expression increases cancer growth and metastasis by mediating MSC-to-CAF transformation in a process that is MZF1- and TGF-β1-dependent. We conclude that tumor-derived OPN engenders MSC-to-CAF transformation in the microenvironment to promote tumor growth and metastasis via the OPN-MZF1-TGF-β1 pathway.

Anti-Angiogenic Drugs: Involvement in Cutaneous Side Effects and Wound-Healing Complication

Significance: The uses of anti-angiogenic drugs have not only made an impact on the battle to eliminate cancer but are also responsible for a number of medical complications. The long-term use of these drugs has increased the spectrum and incidence of cutaneous side effects and wound-healing complications. It is, therefore, necessary to understand the overall impact that these drugs have on patient care. Recent Advances: This review highlights the role of vascular endothelial growth factor and fibroblast growth factor in angiogenesis and wound healing and looks at how angiogenic inhibitors promote wound-healing complications. Critical Issues: With an increased use of anti-angiogenic drugs for the treatment of various cancers and ocular diseases, there is an increased need for clinicians to define the risks and to optimize the usage of these drugs to reduce the incidence of cutaneous side effects and wound-healing complications. In addition, awareness is needed when treating patients on anti-angiogenic drugs so as not to exacerbate potential wound-healing complications when performing surgical procedures. Future Directions: Clinicians and surgeons will need to develop management guidelines to optimize patient care to reduce the risk of morbidity. When performing a surgical procedure, the impact of adverse effects from the use of anti-angiogenic drugs should be considered to ensure the welfare of the patient. In addition, the development of more specific inhibitors is necessary to reduce target effects to reduce the occurrence of adverse effects.

Is age-related macular degeneration a manifestation of systemic disease? New prospects for early intervention and treatment

Age-related macular degeneration (AMD) is a common vision-threatening condition affecting the elderly. AMD shares common risk factors and processes, including vascular and inflammatory pathways, with many systemic disorders. Associations have been reported between AMD and hypertension, cardiovascular disease, cerebrovascular disease, dyslipidaemia, chronic kidney disease and neurodegenerative disorders. An increasing amount of evidence suggests that individuals with AMD are also at risk of systemic diseases such as stroke. In this review, we summarize the latest evidence to support the notion that AMD is an ocular manifestation of systemic disease processes, and discuss the potential systemic side effects of ocular AMD therapy of which general physicians should be aware. Recent genetic discoveries and understanding of the pathogenic pathways in AMD in relation to systemic disorders are also highlighted.

Systemic thromboembolic adverse events in patients treated with intravitreal anti-VEGF drugs for neovascular age-related macular degeneration: an overview

INTRODUCTION

Anti-VEGF therapy improved the quality of life for millions of patients suffering from wet age-related macular degeneration (wet-AMD); unfortunately, this therapy involves multiple injections over many years. The administration of anti-VEGF can overcome the blood-retinal barrier with agents entering the systemic circulation and causing a significant decrease in VEGF serum concentration. Although circulating VEGF protects the integrity and patency of vessels, prolonged anti-VEGF treatment has the potential to increase the risk of thromboembolic events.

AREAS COVERED

In this review, we discuss the safety data from recent trials involving available anti-VEGF drugs.

EXPERT OPINION

During the 2 years of follow-up in the relevant clinical trials, the rates of serious adverse events such as stroke, heart attack and death were similar for patients treated with different anti-VEGF drugs. Moreover the arterial thrombotic risk appears sufficiently low when compared with the natural incidence of arterial thrombotic events in this category of elderly patients and acceptably balanced against the advantage of improved vision. Since the use of these drugs is likely to become increasingly widespread and prolonged, it is desirable that the scientific community improves the pharmacovigilance program on all anti-VEGF drugs, expanding knowledge with studies that compares head to head all four compounds belonging to anti-VEGF armamentarium.

Global prevalence of age-related macular degeneration and disease burden projection for 2020 and 2040: a systematic review and meta-analysis

BACKGROUND

Numerous population-based studies of age-related macular degeneration have been reported around the world, with the results of some studies suggesting racial or ethnic differences in disease prevalence. Integrating these resources to provide summarised data to establish worldwide prevalence and to project the number of people with age-related macular degeneration from 2020 to 2040 would be a useful guide for global strategies.

METHODS

We did a systematic literature review to identify all population-based studies of age-related macular degeneration published before May, 2013. Only studies using retinal photographs and standardised grading classifications (the Wisconsin age-related maculopathy grading system, the international classification for age-related macular degeneration, or the Rotterdam staging system) were included. Hierarchical Bayesian approaches were used to estimate the pooled prevalence, the 95% credible intervals (CrI), and to examine the difference in prevalence by ethnicity (European, African, Hispanic, Asian) and region (Africa, Asia, Europe, Latin America and the Caribbean, North America, and Oceania). UN World Population Prospects were used to project the number of people affected in 2014 and 2040. Bayes factor was calculated as a measure of statistical evidence, with a score above three indicating substantial evidence.

FINDINGS

Analysis of 129,664 individuals (aged 30-97 years), with 12,727 cases from 39 studies, showed the pooled prevalence (mapped to an age range of 45-85 years) of early, late, and any age-related macular degeneration to be 8.01% (95% CrI 3.98-15.49), 0.37% (0.18-0.77), and 8.69% (4.26-17.40), respectively. We found a higher prevalence of early and any age-related macular degeneration in Europeans than in Asians (early: 11.2% vs 6.8%, Bayes factor 3.9; any: 12.3% vs 7.4%, Bayes factor 4.3), and early, late, and any age-related macular degeneration to be more prevalent in Europeans than in Africans (early: 11.2% vs 7.1%, Bayes factor 12.2; late: 0.5% vs 0.3%, 3.7; any: 12.3% vs 7.5%, 31.3). There was no difference in prevalence between Asians and Africans (all Bayes factors <1). Europeans had a higher prevalence of geographic atrophy subtype (1.11%, 95% CrI 0.53-2.08) than Africans (0.14%, 0.04-0.45), Asians (0.21%, 0.04-0.87), and Hispanics (0.16%, 0.05-0.46). Between geographical regions, cases of early and any age-related macular degeneration were less prevalent in Asia than in Europe and North America (early: 6.3% vs 14.3% and 12.8% [Bayes factor 2.3 and 7.6]; any: 6.9% vs 18.3% and 14.3% [3.0 and 3.8]). No significant gender effect was noted in prevalence (Bayes factor <1.0). The projected number of people with age-related macular degeneration in 2020 is 196 million (95% CrI 140-261), increasing to 288 million in 2040 (205-399).

INTERPRETATION

These estimates indicate the substantial global burden of age-related macular degeneration. Summarised data provide information for understanding the effect of the condition and provide data towards designing eye-care strategies and health services around the world.

FUNDING

National Medical Research Council, Singapore.

Maintenance therapy with pegaptanib sodium for neovascular age-related macular degeneration: an exploratory study in Japanese patients (LEVEL-J study)

PURPOSE

To explore the efficacy and safety of pegaptanib sodium as maintenance therapy in Japanese patients with neovascular, age-related macular degeneration (AMD) after induction therapy (LEVEL-J study).

METHODS

A multi-center, prospective study was conducted at 21 medical institutions between 2009 and 2011. Of Japanese neovascular AMD patients with choroidal neovascularization who showed improvement in visual acuity (VA) with induction therapy, those who were scheduled for intravitreal injections of pegaptanib as maintenance therapy were recruited. LogMAR VA was assessed. Booster treatment (unscheduled treatment with other agents) was allowed during the study period if symptoms were judged to have worsened. Safety was assessed by monitoring adverse events and intraocular pressure (IOP).

RESULTS

Of 75 patients included in the analysis, 80 % completed the 54-week study period. Their mean age was 74.7 ± 6.9 years, and 54 patients (72.0 %) were men. The mean number of pegaptanib injections was 5.7 ± 2.6. Booster treatment was not required in 40 eyes (53.3 %). Mean logMAR VA was 0.61 ± 0.31 before induction therapy, 0.26 ± 0.24 before maintenance therapy, and 0.29 ± 0.28 at 54 weeks. No notable change in VA was observed during maintenance therapy. Adverse events were reported in 4 patients (5.3 %), including increased intraocular pressure, cancer, gallstones and recurrence of breast cancer, but mean IOP remained stable during maintenance therapy.

CONCLUSIONS

The results of this exploratory study suggest that maintenance therapy with pegaptanib is potentially an effective and well-tolerated option in Japanese patients with neovascular AMD in whom induction therapy has been successful.

Adverse events and complications associated with intravitreal injection of anti-VEGF agents: a review of literature

Intravitreal injection of anti-vascular endothelial growth factor (VEGF) agents is increasingly used for the treatment of a wide variety of retinal diseases, including age-related macular degeneration, diabetic retinopathy and retinal vascular occlusions, and retinopathy of prematurity. Despite encouraging results in halting the disease and improving the vision, intravitreal injection of anti-VEGF agents may be associated with systemic adverse events and devastating ocular complications. In this review, we provide an overview of safety data for intravitreal injection of common anti-VEGF agents.

The psychological challenge of late-life vision impairment: concepts, findings, and practical implications

The intention is to summarize the body of evidence speaking to the psychological challenges faced by visually impaired older adults, as well as their coping efforts. This evidence is substantiated by a rich set of concepts, theories, and empirical findings that have accumulated under the umbrella of age-related psychoophthalmology (APO). I introduce the field of APO and continue with a discussion of important concepts and theories for a better understanding of adaptational processes in visually impaired older adults. I then summarize the most relevant and most recent data from four areas: (1) everyday competence, (2) cognitive functioning, (3) social functioning, and (4) subjective well-being-related outcomes, depression, and adaptational processes. Thereafter, major insights related to the current state-of-the art psychosocial interventions with visuallyimpaired older adults are reviewed. I close with the need that the public health community should become more aware of and address the psychosocial needs of visually impaired older adults.

Adrenomedullin-RAMP2 system is crucially involved in retinal angiogenesis

Adrenomedullin (ADM) is an endogenous peptide first identified as a strong vasodilating molecule. We previously showed that in mice, homozygous knockout of ADM (ADM(-/-)) or its receptor regulating protein, RAMP2 (RAMP2(-/-)), is embryonically lethal due to abnormal vascular development, thereby demonstrating the importance of ADM and its receptor signaling to vascular development. ADM expression in the retina is strongly induced by ischemia; however, its role in retinal pathophysiology remains unknown. Here, we analyzed oxygen-induced retinopathy (OIR) using heterozygous ADM and RAMP2 knockout mice models (ADM(+/-) or RAMP2(+/-), respectively). In addition, we analyzed the role of the ADM-RAMP2 system during earlier stages of retinal angiogenesis using an inducible endothelial cell-specific RAMP2 knockout mouse line (DI-E-RAMP2(-/-)). Finally, we assessed the ability of antibody-induced ADM blockade to control pathological retinal angiogenesis in OIR. In OIR, neovascular tufts, avascular zones, and hypoxic areas were all smaller in ADM(+/-) retinas compared with wild-type mice. ADM(+/-) retinas also exhibited reduced levels of VEGF and eNOS expression. DI-E-RAMP2(-/-) showed abnormal retinal vascular patterns in the early stages of development. However, ADM enhanced the proliferation and migration of retinal endothelial cells. Finally, we found intravitreal injection of anti-ADM antibody reduced pathological retinal angiogenesis. In conclusion, the ADM-RAMP2 system is crucially involved in retinal angiogenesis. ADM and its receptor system are potential therapeutic targets for controlling pathological retinal angiogenesis.

Periostin-binding DNA aptamer inhibits breast cancer growth and metastasis

Periostin is an extracellular matrix (ECM) protein that is overexpressed in a variety of human cancers, and its functions appear to be linked to tumor growth, metastasis, and angiogenesis. Recent clinical evidence suggests that aberrant periostin expression is correlated with poor outcome in patients with breast cancer. To identify novel tools to regulate the functional role of periostin, we generated benzyl-d(U)TP-modified DNA aptamers that were directed against human periostin (PNDAs) and characterized their functional roles in breast cancer progression. PNDA-3 selectively bound to the FAS-1 domain of periostin with nanomolar affinity and disrupted the interaction between periostin and its cell surface receptors, αvβ3 and αvβ5 integrins. PNDA-3 markedly antagonized the periostin-induced adhesion, migration, and invasion of breast cancer cells and blocked the activation of various components of the αvβ3 and αvβ5 integrin signal transduction pathways. In a 4T1 orthotopic mouse model, PNDA-3 administration significantly reduced primary tumor growth and distant metastasis. Thus, our results demonstrated that periostin-integrin signaling regulates breast cancer progression at multiple levels in tumor cells and the tumor microenvironment. DNA aptamers targeting periostin may potentially be used to inhibit breast cancer progression.

Personalized Medicine in Ophthalmology: From Pharmacogenetic Biomarkers to Therapeutic and Dosage Optimization

Rapid progress in genomics and nanotechnology continue to advance our approach to patient care, from diagnosis and prognosis, to targeting and personalization of therapeutics. However, the clinical application of molecular diagnostics in ophthalmology has been limited even though there have been demonstrations of disease risk and pharmacogenetic associations. There is a high clinical need for therapeutic personalization and dosage optimization in ophthalmology and may be the focus of individualized medicine in this specialty. In several retinal conditions, such as age-related macular degeneration, diabetic macular edema, retinal vein occlusion and pre-threshold retinopathy of prematurity, anti-vascular endothelial growth factor therapeutics have resulted in enhanced outcomes. In glaucoma, recent advances in cytoskeletal agents and prostaglandin molecules that affect outflow and remodel the trabecular meshwork have demonstrated improved intraocular pressure control. Application of recent developments in nanoemulsion and polymeric micelle for targeted delivery and drug release are models of dosage optimization, increasing efficacy and improving outcomes in these major eye diseases.

Drusen quantification for early identification of age related macular degeneration (AMD) using color fundus imaging

Age-related macular degeneration (AMD) is a major cause of visual impairment in the elderly and identifying people with the early stages of AMD is important when considering the design and implementation of preventative strategies for late AMD. Quantification of drusen size and total area covered by drusen is an important risk factor for progression. In this paper, we propose a method to detect drusen and quantify drusen size along with the area covered with drusen in macular region from standard color retinal images. We used combined local intensity distribution, adaptive intensity thresholding and edge information to detect potential drusen areas. The proposed method detected the presence of any drusen with 100% accuracy (50/50 images). For drusen detection accuracy (DDA), the segmentations produced by the automated method on individual images achieved mean sensitivity and specificity values of 74.94% and 81.17%, respectively.

Acute stroke after intravitreal bevacizumab to treat choroidal neovascularization due to angioid streaks in pseudoxanthoma elasticum : a severe systemic adverse event after an off-label procedure

To report the occurrence of acute stroke after intravitreal bevacizumab administration to treat choroidal neovascularization due to angioid streaks in a patient affected by pseudoxanthoma elasticum. A 54-year-old man with pseudoxanthoma elasticum had vision loss because of choroidal neovascularization due to angioid streaks. He underwent two intravitreal bevacizumab injections. Three days after the second procedure the patient was afflicted by acute stroke. Intravitreal injection of bevacizumab to treat choroidal neovascularization due to angioid streaks in pseudoxanthoma elasticum could lead to severe systemic adverse events.

Reduced retinal microvascular density, improved forepaw reach, comparative microarray and gene set enrichment analysis with c-jun targeting DNA enzyme

Retinal neovascularization is a critical component in the pathogenesis of common ocular disorders that cause blindness, and treatment options are limited. We evaluated the therapeutic effect of a DNA enzyme targeting c-jun mRNA in mice with pre-existing retinal neovascularization. A single injection of Dz13 in a lipid formulation containing N-[1-(2,3-dioleoyloxy)propyl]-N,N,N-trimethylammonium methyl-sulfate and 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine inhibited c-Jun expression and reduced retinal microvascular density. The DNAzyme inhibited retinal microvascular density as effectively as VEGF-A antibodies. Comparative microarray and gene expression analysis determined that Dz13 suppressed not only c-jun but a range of growth factors and matrix-degrading enzymes. Dz13 in this formulation inhibited microvascular endothelial cell proliferation, migration and tubule formation in vitro. Moreover, animals treated with Dz13 sensed the top of the cage in a modified forepaw reach model, unlike mice given a DNAzyme with scrambled RNA-binding arms that did not affect c-Jun expression. These findings demonstrate reduction of microvascular density and improvement in forepaw reach in mice administered catalytic DNA.

The estimated prevalence and incidence of late stage age related macular degeneration in the UK

BACKGROUND

UK estimates of age related macular degeneration (AMD) occurrence vary.

AIMS

To estimate prevalence, number and incidence of AMD by type in the UK population aged ≥50 years.

METHODS

Age-specific prevalence rates of AMD obtained from a Bayesian meta-analysis of AMD prevalence were applied to UK 2007-2009 population data. Incidence was estimated from modelled age-specific prevalence.

RESULTS

Overall prevalence of late AMD was 2.4% (95% credible interval (CrI) 1.7% to 3.3%), equivalent to 513 000 cases (95% CrI 363 000 to 699 000); estimated to increase to 679 000 cases by 2020. Prevalences were 4.8% aged ≥65 years, 12.2% aged ≥80 years. Geographical atrophy (GA) prevalence rates were 1.3% (95% CrI 0.9% to 1.9%), 2.6% (95% CrI 1.8% to 3.7%) and 6.7% (95% CrI 4.6% to 9.6%); neovascular AMD (NVAMD) 1.2% (95% CrI 0.9% to 1.7%), 2.5% (95% CrI 1.8% to 3.4%) and 6.3% (95% CrI 4.5% to 8.6%), respectively. The estimated number of prevalent cases of late AMD were 60% higher in women versus men (314 000 cases in women, 192 000 men). Annual incidence of late AMD, GA and NVAMD per 1000 women was 4.1 (95% CrI 2.4% to 6.8%), 2.4 (95% CrI 1.5% to 3.9%) and 2.3 (95% CrI 1.4% to 4.0%); in men 2.6 (95% CrI 1.5% to 4.4%), 1.7 (95% CrI 1.0% to 2.8%) and 1.4 (95% CrI 0.8% to 2.4%), respectively. 71 000 new cases of late AMD were estimated per year.

CONCLUSIONS

These estimates will guide health and social service provision for those with late AMD and enable estimation of the cost of introducing new treatments.

Long-term effectiveness of intravitreal bevacizumab for choroidal neovascularization secondary to angioid streaks in pseudoxanthoma elasticum

PURPOSE

To investigate the long-term effectiveness of intravitreal bevacizumab for treating active choroidal neovascularizations in pseudoxanthoma elasticum (PXE).

METHODS

Fourteen patients (16 eyes) received intravitreal bevacizumab (1.5 mg) and were investigated monthly. Further treatments were administered depending on disease activity. Examinations included best-corrected visual acuity, biomicroscopy, optical coherence tomography, fluorescein angiography and indocyanine green angiography, fundus autofluorescence, and digital fundus photography. Areas of atrophy of the retinal pigment epithelium and retinal fibrosis were quantified using semiautomated detection on fundus autofluorescence images.

RESULTS

Mean age of the cohort was 55 ± 13 years, and mean best-corrected visual acuity at baseline was 20/80 (logarithm of the minimum angle of resolution, 0.56, SD, 0.51). At last follow-up, after an average of 6.5 ± 5.7 injections over 28 months, best-corrected visual acuity was 20/40 (logarithm of the minimum angle of resolution, 0.31, SD, 0.32; P = 0.04). Central retinal thickness was reduced from 254 ± 45 μm to 214 ± 40 μm (P = 0.035). The size of retinal pigment epithelial atrophy and retinal fibrosis measured on fundus autofluorescence images increased in both the treated eye and the fellow eye (P < 0.05). Best-corrected visual acuity of patients with early disease compared with that of those with advanced disease improved significantly more over the treatment course (20/25 vs. 20/63; P = 0.008).

CONCLUSION

Intravitreal bevacizumab therapy demonstrates long-term effectiveness by preserving function in advanced disease and improving function in early disease. Best results of treating active choroidal neovascularizations in PXE are achieved when treatment starts the earliest possible.

Intravitreal bevacizumab for the treatment of choroidal neovascularization secondary to angioid streaks: one year of follow-up

PURPOSE

To evaluate the efficacy and safety of intravitreal bevacizumab at one year follow-up, for the treatment of choroidal neovascularization (CNV) associated with angioid streaks.

METHODS

A retrospective case series of eighteen eyes of 17 patients with CNV secondary to angioid streaks treated with intravitreal bevacizumab between October 2006 and May 2008. Ophthalmic evaluation including best corrected visual acuity (BCVA), slit lamp biomicroscopic examination, optical coherence tomography (OCT) and fluorescein angiography, was performed before and after treatment. Retreatment was given every 4-6 weeks in case of persistent symptoms or CNV activity on OCT. Main outcome measures were changes in BCVA and central retinal thickness on OCT.

RESULTS

The mean number of injections was 4.8 at 1 year. Twelve eyes (66.6%) received five injections or more. The mean BCVA at baseline was 20/80 (range 20/400 to 20/32) and improved to 20/44 (range 20/160 to 20/20) at 1 year (p = 0.014). The BCVA improved by three or more lines in eleven eyes (61.11%) and remained within two lines of baseline in seven eyes (38.8%). Mean central retinal thickness was 404.2 μm (range 160-602 μm) at baseline and decreased to 300.5 μm (range 150-523 μm) at 1 year (p = 0.022). No ocular or systemic complications were noted.

CONCLUSION

The 1-year outcomes suggest intravitreal bevacizumab to be a promising treatment for CNV associated with angioid streaks, resulting in both functional and anatomical improvements. Repeated injections are needed to maintain these results. Further long term studies are required to confirm these findings.

Monthly ranibizumab for choroidal neovascularizations secondary to angioid streaks in pseudoxanthoma elasticum: a one-year prospective study

PURPOSE

To evaluate the efficacy and safety of monthly intravitreal ranibizumab for the treatment of choroidal neovascularizations (CNV) secondary to angioid streaks (AS) in pseudoxanthoma elasticum (PXE).

DESIGN

Twelve-month prospective, open-label, uncontrolled, nonrandomized interventional clinical trial.

METHODS

In 7 patients, 1 eye with an active CNV was injected with 0.5 mg ranibizumab monthly over 1 year. Distance and reading visual acuity, reading speed, angiographic findings, and central retinal thickness (CRT) on optical coherence tomography were assessed at each visit. Central retinal light increment sensitivity (LIS) was assessed by microperimetry at baseline, at 6 months, and 3 to 4 months after the last injection.

RESULTS

Best-corrected visual acuity increased significantly from baseline to month 12 (20/63 or 61 ETDRS letters to 20/32 or 73 ETDRS letters; P = .012). The effect was maintained 3 months later (61 ETDRS letters to 72 ETDRS letters; P = .055). Reading acuity and speed could be maintained throughout the study. Central LIS improved (6.6 dB, SD ± 5.9 at baseline to 7.4 dB, SD ± 6.2 at last follow-up; P < .001). Leakage from active CNVs subsided. Mean change in CRT from baseline to month 12 and 15 was -86 μm (P = .074) and -65 μm (P = .182), respectively. No serious adverse events occurred.

CONCLUSIONS

Efficacy outcomes indicate a beneficial therapeutic effect of intravitreal ranibizumab on central visual function including retinal LIS. Both the functional and morphologic response based on angiographic and OCT findings to ranibizumab treatment implicate an important pathophysiological role of vascular endothelial growth factor in CNVs secondary to AS in PXE. Intravitreal ranibizumab appears to be a safe and efficacious treatment in these patients.

A systematic review of the efficacy and safety outcomes of anti-VEGF agents used for treating neovascular age-related macular degeneration: comparison of ranibizumab and bevacizumab

OBJECTIVE

To systematically review ocular and systemic events in treatment of wet age-related macular degeneration (AMD) with anti-vascular endothelial growth factor antibodies, ranibizumab and bevacizumab, and to provide a detailed perspective of their differences on clinical use, efficacy and safety.

RESEARCH DESIGN AND METHODS

This review was based on a 2010 PubMed literature search performed using two separate terms: 'lucentis' OR 'ranibizumab' AND 'age-related macular degeneration' OR 'AMD' or 'avastin' OR 'bevacizumab' AND 'age-related macular degeneration' OR 'AMD'. A clinical diagnosis of wet AMD was defined by the authors of the trial reports. Clinical studies that met Level I or Level II evidence criteria were considered for review.

FINDINGS

Eight large, randomized, controlled trials of ranibizumab (Level I) included 1,485 patients (range 162-716) and four open-label studies of ranibizumab (Level II) included 4,484 patients (range 32-4,300). Six studies (one Level I, five Level II) of bevacizumab included 424 patients (range 28-165). All demonstrated improvements in visual acuity. Only one study (Level II) compared the efficacy of ranibizumab and bevacizumab. Adverse ocular and systemic safety events occurring during the study were prospectively recorded for ranibizumab, irrespective of their suspected relationship to study treatments. Only three of six bevacizumab studies reported details of adverse ocular or systemic events. There was extensive Level I and Level II evidence to support both the efficacy and safety of ranibizumab in wet AMD. Data suggest that bevacizumab provides efficacy in wet AMD, but the safety profile of intravitreal bevacizumab remains to be established.

CONCLUSION

In contrast to ranibizumab, current safety data for bevacizumab are incomplete and not yet robust. If the medical community remains committed to using intravitreal bevacizumab, it is critical to establish that it has an acceptable safety profile, supported by evidence-based medicine. Considerable further research is warranted to achieve this.

ToF-SIMS analysis of ocular tissues reveals biochemical differentiation and drug distribution

Time-of-flight secondary ion mass spectrometry (ToF-SIMS) was used to obtain mass spectra from three ocular tissues, the lens, the vitreous and the retina. All three tissues were extracted from control ovine eyes and ovine eyes treated with model drug. To identify variations in surface biochemistry of each ocular tissue, principal component analysis (PCA) was applied to ToF-SIMS data. Interesting physiological differences in Na(+) and K(+) distribution were shown across the three tissue types, with other elements including Ca(2+) and Fe(2+) distribution also detected. In addition to the identification of small molecules and smaller molecular fragments, larger molecules such as phosphocholine were also detected. The ToF-SIMS data were also used to identify the presence of a model drug compound (amitriptyline--chosen as a generic drug structure) within all three ocular tissues, with model drug detected predominantly across the vitreous tissue samples. This study demonstrates that PCA can be successfully applied to ToF-SIMS data from different ocular tissues and highlights the potential of coupling multivariate statistics with surface analytical techniques to gain a greater understanding of the biochemical composition of tissues and the distribution of pharmaceutically active small molecules within these tissues.

Clinical risk factors for age-related macular degeneration: a systematic review and meta-analysis

BACKGROUND

Age-related macular degeneration (AMD) is the leading cause of blindness in Western countries. Numerous risk factors have been reported but the evidence and strength of association is variable. We aimed to identify those risk factors with strong levels of evidence which could be easily assessed by physicians or ophthalmologists to implement preventive interventions or address current behaviours.

METHODS

A systematic review identified 18 prospective and cross-sectional studies and 6 case control studies involving 113,780 persons with 17,236 cases of late AMD that included an estimate of the association between late AMD and at least one of 16 pre-selected risk factors. Fixed-effects meta-analyses were conducted for each factor to combine odds ratio (OR) and/or relative risk (RR) outcomes across studies by study design. Overall raw point estimates of each risk factor and associated 95% confidence intervals (CI) were calculated.

RESULTS

Increasing age, current cigarette smoking, previous cataract surgery, and a family history of AMD showed strong and consistent associations with late AMD. Risk factors with moderate and consistent associations were higher body mass index, history of cardiovascular disease, hypertension, and higher plasma fibrinogen. Risk factors with weaker and inconsistent associations were gender, ethnicity, diabetes, iris colour, history of cerebrovascular disease, and serum total and HDL cholesterol and triglyceride levels.

CONCLUSIONS

Smoking, previous cataract surgery and a family history of AMD are consistent risk factors for AMD. Cardiovascular risk factors are also associated with AMD. Knowledge of these risk factors that may be easily assessed by physicians and general ophthalmologists may assist in identification and appropriate referral of persons at risk of AMD.

A scalable controlled-release device for transscleral drug delivery to the retina

A transscleral drug-delivery device, designed for the administration of protein-type drugs, that consists of a drug reservoir covered with a controlled-release membrane was manufactured and tested. The controlled-release membrane is made of photopolymerized polyethylene glycol dimethacrylate (PEGDM) that contains interconnected collagen microparticles (COLs), which are the routes for drug permeation. The results showed that the release of 40-kDa FITC-dextran (FD40) was dependent on the COL concentration, which indicated that FD40 travelled through the membrane-embedded COLs. Additionally, the sustained-release drug formulations, FD40-loaded COLs and FD40-loaded COLs pelletized with PEGDM, fine-tuned the release of FD40. Capsules filled with COLs that contained recombinant human brain-derived neurotrophic factor (rhBDNF) released bioactive rhBDNF in a manner dependent on the membrane COL concentration, as was found for FD40 release. When capsules were sutured onto sclerae of rabbit eyes, FD40 was found to spread to the retinal pigment epithelium. Implantation of the device was easy, and it did not damage the eye tissues. In conclusion, our capsule is easily modified to accommodate different release rates for protein-type drugs by altering the membrane COL composition and/or drug formulation and can be implanted and removed with minor surgery. The device thus has great potential as a conduit for continuous, controlled drug release.

Diabetic retinopathy

Diabetic retinopathy is a common and specific microvascular complication of diabetes, and remains the leading cause of preventable blindness in working-aged people. It is identified in a third of people with diabetes and associated with increased risk of life-threatening systemic vascular complications, including stroke, coronary heart disease, and heart failure. Optimum control of blood glucose, blood pressure, and possibly blood lipids remains the foundation for reduction of risk of retinopathy development and progression. Timely laser therapy is effective for preservation of sight in proliferative retinopathy and macular oedema, but its ability to reverse visual loss is poor. Vitrectomy surgery might occasionally be needed for advanced retinopathy. New therapies, such as intraocular injection of steroids and antivascular endothelial growth-factor agents, are less destructive to the retina than are older therapies, and could be useful in patients who respond poorly to conventional therapy. The outlook for future treatment modalities, such as inhibition of other angiogenic factors, regenerative therapy, and topical therapy, is promising.

Age-related macular degeneration and risk of coronary heart disease and stroke: the Cardiovascular Health Study

PURPOSE

To examine the associations of age-related macular degeneration (AMD) with incident coronary heart disease (CHD) and stroke in the Cardiovascular Health Study.

DESIGN

Population-based prospective cohort study.

PARTICIPANTS

A total of 1786 white and African-American participants free of CHD or 2228 participants free of stroke, aged 69 to 97 years.

METHODS

AMD was evaluated from photographs taken in 1997 and 1998.

MAIN OUTCOME MEASURES

Incident CHD and stroke ascertained using standardized methods.

RESULTS

Of the 1786 persons free of CHD, 303 developed incident CHD over 7 years. Participants with early AMD (n = 277) had a higher cumulative incidence of CHD than participants without early AMD (25.8% vs. 18.9%, P = 0.001). By adjusting for age, gender, race, systolic and diastolic blood pressure, hypertension status, fasting glucose, triglyceride, low-density lipoprotein cholesterol, cigarette smoking, pack years of smoking, and C-reactive protein, the presence of early AMD was associated with an increased risk of incident CHD (hazard ratio 1.57; 95% confidence interval, 1.17-2.22). Late AMD (n = 25) was not associated with incident CHD (hazard ratio 0.78; 95% confidence interval, 0.25-2.48). Among 2228 persons at risk, 198 developed incident stroke; neither early nor late AMD was associated with incident stroke.

CONCLUSIONS

This study suggests persons with early AMD have a higher risk of CHD but not stroke in a population aged 69 to 97 years. This provides further support that AMD is associated with underlying systemic vascular disease.

Pseudoxanthoma elasticum: genetics, clinical manifestations and therapeutic approaches

Pseudoxanthoma elasticum (PXE) is an inherited disorder that is associated with accumulation of mineralized and fragmented elastic fibers in the skin, vascular walls, and Bruch's membrane in the eye. Clinically, patients exhibit characteristic lesions of the posterior segment of the eye including peau d'orange, angioid streaks, and choroidal neovascularisations, of the skin including soft, ivory-colored papules in a reticular pattern that predominantly affect the neck and large flexor surfaces, and of the cardiovascular system with peripheral and coronary arterial occlusive disease as well as gastrointestinal bleedings. There is yet no definitive therapy. Recent studies suggest that PXE is inherited almost exclusively as an autosomal recessive trait. Its prevalence has been estimated to be 1:25,000-100,000. Very recently, the ABCC6 gene on chromosome 16p13.1 was found to be associated with the disease. Mutations within ABCC6 cause reduced or absent transmembraneous transport that leads to accumulation of extracellular material. Presumably, this mechanism causes calcification of elastic fibers. Despite the characteristic clinical features, the variability in phenotypic expressions, and the low prevalence may be responsible for the disease being underdiagnosed. This review compiles and summarizes current knowledge of PXE pathogenesis and clinical findings. Furthermore, different therapeutic strategies to treat retinal manifestations are discussed, including thermal laser coagulation, photodynamic therapy, and intravitreal injections of drugs inhibiting vascular endothelial growth factor.

Age-related macular degeneration: current treatments

Purpose:

Although important progress has been made in understanding age-related macular degeneration (AMD), management of the disease continues to be a challenge. AMD research has led to a widening of available treatment options and improved prognostic perspectives. This essay reviews these treatment options.

Design:

Interpretative essay.

Methods:

Literature review and interpretation.

Results:

Current treatments to preserve vision in patients with non-exudative AMD include antioxidant vitamins and mineral supplementations. Exudative AMD is currently most often treated monthly with anti-VEGF intravitreal injections. However, investigators are beginning to experiment with combination therapy and surgical approaches in an attempt to limit the number of treatment and reduce the financial burden on the health care system.

Conclusion:

By better understanding the basis and pathogenesis of AMD, newer therapies will continue to be developed that target specific pathways in patients with AMD, with the hoped for outcome of better management of the disease and improved visual acuity.

A role for a CXCR2/phosphatidylinositol 3-kinase gamma signaling axis in acute and chronic vascular permeability

Most proangiogenic polypeptide growth factors and chemokines enhance vascular permeability, including vascular endothelial growth factor (VEGF), the main target for anti-angiogenic-based therapies, and interleukin-8 (IL-8), a potent proinflammatory mediator. Here, we show that in endothelial cells IL-8 initiates a signaling route that converges with that deployed by VEGF at the level of the small GTPase Rac1 and that both act through the p21-activated kinase to promote the phosphorylation and internalization of VE-cadherin. However, whereas VEGF activates Rac1 through Src-related kinases, IL-8 specifically signals to Rac1 through its cognate G protein-linked receptor, CXCR2, and the stimulation of the phosphatidylinositol 3-kinase gamma (PI3Kgamma) catalytic isoform, thereby providing a specific molecular targeted intervention in vascular permeability. These results prompted us to investigate the potential role of IL-8 signaling in a mouse model for retinal vascular hyperpermeability. Importantly, we observed that IL-8 is upregulated upon laser-induced retinal damage, which recapitulates enhanced vascularization, leakage, and inflammatory responses. Moreover, blockade of CXCR2 and PI3Kgamma was able to limit neovascularization and choroidal edema, as well as macrophage infiltration, therefore contributing to reduce retinal damage. These findings indicate that the CXCR2 and PI3Kgamma signaling pathway may represent a suitable target for the development of novel therapeutic strategies for human diseases characterized by vascular leakage.