Neovascular age-related macular degeneration: present and future treatment options

SIRT3 Activation a Promise in Drug Development? New Insights into SIRT3 Biology and Its Implications on the Drug Discovery Process

Sirtuins catalyze deacetylation of lysine residues with a NAD+-dependent mechanism. In mammals, the sirtuin family is composed of seven members, divided into four subclasses that differ in substrate specificity, subcellular localization, regulation, as well as interactions with other proteins, both within and outside the epigenetic field. Recently, much interest has been growing in SIRT3, which is mainly involved in regulating mitochondrial metabolism. Moreover, SIRT3 seems to be protective in diseases such as age-related, neurodegenerative, liver, kidney, heart, and metabolic ones, as well as in cancer. In most cases, activating SIRT3 could be a promising strategy to tackle these health problems. Here, we summarize the main biological functions, substrates, and interactors of SIRT3, as well as several molecules reported in the literature that are able to modulate SIRT3 activity. Among the activators, some derive from natural products, others from library screening, and others from the classical medicinal chemistry approach.

OCT-angiography follow-up of choroidal neovascularization treated with treat-and- extend aflibercept regimen to avoid over-treatment

PURPOSE

To propose optical coherence tomography angiography (OCT-A) for the follow-up of neovascular age-related macular degeneration (nAMD) treated with a treat-and-extend (T&E) aflibercept regimen to avoid overtreatment.

METHODS

Retrospective, cohort, pilot study. We analysed 16 consecutive-treatment naïve nAMD eyes following up 2-years at the Eye Clinic, Bari, Italy. Intravitreal aflibercept injections in the T&E regimen for no less than 12 months, during which the macula was dry without any sign of intraretinal or subretinal fluid (SRF) at each visit, were performed. Parametric data were evaluated using an analysis of variance (ANOVA); any non-parametric statistical calculations were performed using the Wilcoxon and Mann-Whitney test.

RESULTS

The average number of injections during follow-up was: 8.8 ± 1. Treatment regimen adjustments were 4 weeks (W), 8W (4 + 4), 10W (8 + 2), 12W (8 + 4, or 10 + 2). No significant CNV size change from 4 to 8W (-0.027 ± 0.22 mm², p = 0.088), and from 8 to 12W (-0.04 ± 0.11 mm², p = 0.065) were found. Likewise, no significant decrease in choriocapillaris flow (CF) was detected (p = 0.056).

CONCLUSION

We suggest that OCT-A may be useful in the evaluation of dry macula to decide the best approach for perchance adjusting injection intervals based on changes of CNV size.

Recent Advances and the Mechanism of Astaxanthin in Ophthalmological Diseases

Astaxanthin (AST) is a naturally occurring carotenoid that has strong antioxidant, anti-inflammatory, and antiapoptosis effects and is used for the prevention of cancer. There is growing evidence that AST has multiple protective effects against various eye diseases. This article reviews the function and the potential mechanism of AST in dry eye syndrome, keratitis, cataract, diabetic retinopathy, age-related macular degeneration, high intraocular pressure, and other ocular diseases. It provides a theoretical basis for the clinical application of AST as a potential nutraceutical.

Therapeutic effect of Keap1-Nrf2-ARE pathway-related drugs on age-related eye diseases through anti-oxidative stress

Age-related eye diseases, including cataract, glaucoma, diabetic retinopathy (DR), and age-related macular degeneration (AMD), are the leading causes of vision loss in the world. Several studies have shown that the occurrence and development of these diseases have an important relationship with oxidative stress in the eye. The Keap1-Nrf2-ARE pathway is a classical pathway that resists oxidative stress and inflammation in the body. This pathway is also active in the development of age-related eye diseases. A variety of drugs have been shown to treat age-related eye diseases through the Keap1-Nrf2-ARE (Kelch-like ECH-Associating protein 1- nuclear factor erythroid 2 related factor 2-antioxidant response element) pathway. This review describes the role of oxidative stress in the development of age-related eye diseases, the function and regulation of the Keap1-Nrf2-ARE pathway, and the therapeutic effects of drugs associated with this pathway on age-related eye diseases.

Depression, Anxiety, Somatization Disorder, and Adjustment Disorder in Older Patients with Exudative Age-related Macular Degeneration

Purpose: The aim of this study was to analyze the prevalence of depression, anxiety, somatization disorder, and adjustment disorder in older patients diagnosed with exudative age-related macular degeneration (AMD) and to evaluate the relationship between exudative AMD and psychological disease.Methods: The 2016 Health Insurance Review and Assessment Service-Aged Patient Sample was applied in this study. The subjects were divided into two groups: AMD patients undergoing intravitreal injection treatment and a control group. Comorbidities were evaluated using the Charlson Comorbidity Index.Results: A total of 1,319,052 subjects were selected, of which 3,134 were in the exudative AMD group receiving intravitreal injections. The average age of the subjects was 74.7 ± 6.7 years, and 41.8% were male. In patients with exudative AMD, the prevalence of depression, anxiety, somatization disorder, and adjustment disorder were 16%, 20%, 0.5%, and 0.4%, respectively; in particular, the prevalence of depression and adjustment disorder were significantly higher than in the control group. In multivariate regression analysis, exudative AMD was a significant factor of depression (odds ratio [OR] 1.2, 95% confidence interval [CI] 1.08-1.31, p < 0.001) and adjustment disorder (OR 2.47, 95% CI 1.47-4.18, p < 0.001). However, the association between AMD and anxiety or somatization disorder was not statistically significant.Conclusions: Exudative AMD showed a significant association with psychiatric disease, such as depression, and requires close clinical attention.

A novel dendrimer-based complex co-modified with cyclic RGD hexapeptide and penetratin for noninvasive targeting and penetration of the ocular posterior segment

Noninvasive drug delivery is a promising treatment strategy for ocular posterior segment diseases. Many physiological and anatomical barriers of the eye considerably restrict effective diffusion of therapeutics to the target site. To overcome this problem, a novel cyclic arginine-glycine-aspartate (RGD) hexapeptide and penetratin (PEN) co-modified PEGylation polyamidoamine (PAMAM) was designed as a nanocarriers (NCs), and its penetrating and targeting abilities were evaluated. In this study, we show that PAMAM-PEG (reaction molar ratio 1:32) has a relatively high grafting efficiency and low cytotoxicity. The particle size was within the range of 15-20 nm after modification with RGD and PEN. Cellular uptake of RGD-modified NCs involved significant affinity toward integrin αvβ3, which validated the targeting of neovasculature. An in vitro permeation study indicated that modification with PEN significantly improved penetration of the NCs (1.5 times higher). In vivo ocular distribution studies showed that, the NCs (modified with PEN or co-modified with RGD and PEN) were highly distributed in the cornea and retina (p < .001), and modification extended retinal retention time for more than 12 h. Therefore, these NCs appear to be a promising noninvasive ocular drug delivery system for ocular posterior segment diseases.

Radiation Therapy for Benign Disease: Keloids, Macular Degeneration, Orbital Pseudotumor, Pterygium, Peyronie Disease, Trigeminal Neuralgia

Although the use of ionizing radiation on malignant conditions has been well established, its application on benign conditions has not been fully accepted and has been inadequately recognized by health care providers outside of radiation therapy. Most frequently, radiation therapy in these benign conditions is used along with other treatment modalities, such as surgery, when the condition causes significant disability or could even lead to death. Radiation therapy can be helpful for inflammatory/proliferative disorders. This article discusses the present use of radiation therapy for some of the most common benign conditions.

Secretogranin III as a novel target for the therapy of choroidal neovascularization

Wet age-related macular degeneration (AMD) with choroidal neovascularization (CNV) is a leading cause of vision loss in the elderly. The advent of anti-vascular endothelial growth factor (VEGF) drugs represents a major breakthrough in wet AMD therapy but with limited efficacy to improve visual acuity. Secretogranin III (Scg3, SgIII) was recently discovered as a novel angiogenic factor with VEGF-independent mechanisms. Scg3-neutralizing monoclonal antibody (mAb) was reported to alleviate pathological retinal neovascularization in oxygen-induced retinopathy mice and retinal vascular leakage in diabetic mice with high efficacy and disease selectivity. Herein we investigated whether Scg3 is a novel angiogenic target for CNV therapy in mouse models. We found that anti-Scg3 ML49.3 mAb inhibited Scg3-induced proliferation and Src phosphorylation in human retinal microvascular endothelial cells. Intravitreal injection of Scg3-neutralizing polyclonal antibodies (pAb) or mAb significantly attenuated laser-induced CNV leakage, CNV 3D volume, lesion area and vessel density. Furthermore, subcutaneous administration of Scg3-neutralizing pAb or mAb significantly prevented Matrigel-induced CNV. The efficacy of anti-Scg3 pAb or mAb was comparable to VEGF inhibitor aflibercept. These findings suggest that Scg3 plays an important role in CNV pathogenesis and that anti-Scg3 mAb efficiently ameliorates laser- or Matrigel-induced CNV.

Celastrol protects human retinal pigment epithelial cells against hydrogen peroxide mediated oxidative stress, autophagy, and apoptosis through sirtuin 3 signal pathway

Age-related macular degeneration (AMD), one of the most common causes of visual impairment, often occurrs in the elderly in developed countries. Oxidative stress, autophagy, and apoptosis of retinal pigment epithelial (RPE) cells play roles in the pathogenesis of AMD. In the current study, the protective effect of celastrol against hydrogen peroxide (H₂ O₂ )-induced oxidative stress and apoptosis was investigated using a human RPE cell line (ARPE-19). H₂ O₂ inhibited ARPE-19 cells' survival and autophagy and induced their oxidative stress and apoptosis. Compared with the H₂ O₂ group, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay showed that celastrol increased ARPE-19 cells' survival in a dose- and time-dependent manner. Further, studies have suggested that celastrol has antioxidative stress and antiapoptosis effects in H₂ O₂ -treated ARPE-19 cells. Also, cell autophagy is activated by celastrol in H₂ O₂ -treated ARPE-19 cells. Reverse transcription polymerase chain reaction and Western blot showed that celastrol elevated the messenger RNA (mRNA) and protein expression of sirtuin 3 (SIRT3) in H₂ O₂ -induced ARPE-19 cells. Inhibition of the level of SIRT3 by SIRT3 small interfering RNA (siRNA) reversed the effects of celastrol on oxidative stress, autophagy, and apoptosis in H₂ O₂ -induced ARPE-19 cells. In conclusion, these observations suggest that celastrol activates the SIRT3 pathway in RPE cells and protects against H₂ O₂ -induced oxidative stress and apoptosis.

Pathogenic role and therapeutic potential of pleiotrophin in mouse models of ocular vascular disease

Angiogenic factors play an important role in the pathogenesis of diabetic retinopathy (DR), neovascular age-related macular degeneration (nAMD) and retinopathy of prematurity (ROP). Pleiotrophin, a well-known angiogenic factor, was recently reported to be upregulated in the vitreous fluid of patients with proliferative DR (PDR). However, its pathogenic role and therapeutic potential in ocular vascular diseases have not been defined in vivo. Here using corneal pocket assays, we demonstrated that pleiotrophin induced angiogenesis in vivo. To investigate the pathological role of pleiotrophin we used neutralizing antibody to block its function in multiple in vivo models of ocular vascular diseases. In a mouse model of DR, intravitreal injection of pleiotrophin-neutralizing antibody alleviated diabetic retinal vascular leakage. In a mouse model of oxygen-induced retinopathy (OIR), which is a surrogate model of ROP and PDR, we demonstrated that intravitreal injection of anti-pleiotrophin antibody prevented OIR-induced pathological retinal neovascularization and aberrant vessel tufts. Finally, pleiotrophin-neutralizing antibody ameliorated laser-induced choroidal neovascularization, a mouse model of nAMD, suggesting that pleiotrophin is involved in choroidal vascular disease. These findings suggest that pleiotrophin plays an important role in the pathogenesis of DR with retinal vascular leakage, ROP with retinal neovascularization and nAMD with choroidal neovascularization. The results also support pleiotrophin as a promising target for anti-angiogenic therapy.

Effect of cytokeratin 17 on retinal pigment epithelium degeneration and choroidal neovascularization

AIM

To study the effects of cytokeratin 17 (CK17) on sodium iodate (NaIO3) induced rat retinal pigment epithelium (RPE) degeneration, laser induced rat choroidal neovascularization (CNV), and oxidative stress of human retinal pigment epithelium cells (ARPE-19) and human umbilical vein endothelial cell (HUVEC).

METHODS

Thirty 8-week-old male Brown Norway rats were randomly divided into 3 groups, 10 rats in control group treated with solvent alone; 10 rats in NaIO3 group treated with solvent and 35 mg/kg NaIO3 injection through hypoglossal vein and 10 rats in CK17+NaIO3 group treated with 1% CK17 eye drop 3 times a day for 1wk before and 4wk after NaIO3 injection. RPE function was measured with c-wave of electroretinogram (ERG). Another 20 rats were randomly divided into 2 groups. Of them 10 rats in CK17 group were anesthetized to receive Nd:YAG laser and given 1% CK17 eye drop before same as above; 10 rats in control were received Nd:YAG and treated with solvent. The development of choroidal neovascularization (CNV) was determined by fundus fluorescein angiography (FFA) performed on 4wk after laser. Methylthiazoly tetrazolium (MTT) assay was used to study effect of CK17 on various oxidants induced injury in ARPE-19 and HUVEC in vitro.

RESULTS

Four weeks after NaIO3 injection, the c-wave amplitude of ERG was 0.393±0.02 V in the control group, 0.184±0.018 V in NaIO3 group and 0.3±0.01 V in CK17+NaIO3 group. There was a significant reversal of the c-wave by CK17 as compared to NaIO3 group (P<0.01). Four weeks after laser, the size of the CNV lesion was 2.57±0.27 mm(2) in control group and 1.64±0.08 mm(2) in CK17 group. The lesion size significantly diminished in CK17 group (P<0.01). The in vitro results showed CK17 also reversed the various oxidants induced injuries in ARPE-19 at the dose of 100 µg/mL and enhanced the injury in HUVECs at different concentrations.

CONCLUSION

CK17 can significantly protect RPE from NaIO3 induced degeneration in vivo and in vitro and also could reverse the various oxidants induced injuries in vitro. It inhibits the development of CNV in rat model, interfered with vascular endothelial cell proliferation in vitro.

Anxiety and depression in patients with advanced macular degeneration: current perspectives

Age-related macular degeneration (AMD) - despite advances in prevention and medical treatment options - remains prevalent among older adults, often resulting in functional losses that negatively affect the mental health of older adults. In particular, the prevalence of both anxiety and depression in patients with AMD is high. Along with medical treatment options, low vision rehabilitation and AMD-specific behavioral and self-management programs have been developed and have demonstrated effectiveness in improving the mental health of AMD patients. This article reviews the prevalence of anxiety and depression in patients with advanced AMD, discusses potential mechanisms accounting for the development of depression and anxiety in AMD patients, presents the state-of the-art of available interventions for addressing anxiety and depression in AMD patients, and delineates recommendations for eye care professionals regarding how to screen for these two prevalent mental health problems and how to facilitate appropriate treatment for patients with AMD.

Coaxial Electrospray of Ranibizumab-Loaded Microparticles for Sustained Release of Anti-VEGF Therapies

Age-related macular degeneration (AMD) is the leading cause of vision loss and blindness in people over age 65 in industrialized nations. Intravitreous injection of anti-VEGF (vascular endothelial growth factor) therapies, such as ranibizumab (trade name: Lucentis), provides an effective treatment option for neovascular AMD. We have developed an improved coaxial electrospray (CES) process to encapsulate ranibizumab in poly(lactic-co-glycolic) acid (PLGA) microparticles (MPs) for intravitreous injection and sustained drug release. This microencapsulation process is advantageous for maintaining the stability of the coaxial cone-jet configurations and producing drug-loaded MPs with as high as 70% encapsulation rate and minimal loss of bioactivitiy. The utility of this emerging process in intravitreous drug delivery has been demonstrated in both benchtop and in vivo experiments. The benchtop test simulates ocular drug release using PLGA MPs encapsulating a model drug. The in vivo experiment evaluates the inflammation and retinal cell death after intravitreal injection of the MPs in a chick model. The experimental results show that the drug-load MPs are able to facilitate sustained drug release for longer than one month. No significant long term microglia reaction or cell death is observed after intravitreal injection of 200 μg MPs. The present study demonstrates the technical feasibility of using the improved CES process to encapsulate water-soluble drugs at a high concentration for sustained release of anti-VEGF therapy.

Age-related macular degeneration: linking clinical presentation to pathology

Age-related macular degeneration (AMD) is one of the leading causes of blindness worldwide in the elderly population. Optometrists, as primary eye health care providers, require the skills and knowledge to accurately diagnose and manage AMD patients. There is an overwhelming body of research related to the clinical presentation, etiology, epidemiology, and pathology of this disease. Additionally, the evolution of new imaging modalities creates new opportunities to clinically detect and analyze previously uncharacterized and earlier changes in the retina. The challenge for optometrists is to combine all this information into an applicable knowledge base for use in everyday clinical assessment of AMD so that timely and accurate referrals can be made to retinal specialists. This review attempts to address this issue by linking the clinical presentation of AMD with the underlying disease biology. We emphasize the contribution of recent noninvasive imaging technologies to the clinical assessment of early and more advanced AMD including optical coherence tomography, fundus autofluorescence, and infrared reflectance.

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.

Management of significant reactivation of old disciform scars in wet age-related macular degeneration

BACKGROUND

Fibrotic disciform scars represent the end-stage of wet age-related macular degeneration (AMD) and ophthalmologists tend not to treat them. However, reactivation can occur resulting in further worsening of patients. The aim of this study is to describe the clinical outcomes of 10 patients with disciform scars from age-related macular degeneration (AMD) that have subsequently reactivated.

METHODS

Indocyanine green angiography (ICG) was used to identify the active areas and these "hot spots" (HS) that were subsequently treated with focal laser photocoagulation.

RESULTS

In 10 out of 11 patients with potential reactivation of an AMD scar, a treatable HS was found on the ICG at the border of the disciform scar. The identified HS was treated with focal laser photocoagulation. Post treatment these areas became inactive. However in 2 cases, reactivation occurred requiring retreatment a few months later.

CONCLUSIONS

AMD patients who are noted to have disciform scars that are increasing in size and signs of activation such as lipid exudation and subretinal haemorrhage should undergo ICG imaging to look for HS. These patients could benefit from focal laser to stabilize the disease and avoid complications and further peripheral visual loss. It is suspected that these patients may have the polypoidal subtype of AMD.

Bevacizumab versus Ranibizumab on As-Needed Treatment Regimen for Neovascular Age-Related Macular Degeneration in Turkish Patients

Purpose. To compare the efficacy of intravitreal bevacizumab versus ranibizumab in the treatment of neovascular age-related macular degeneration (nAMD). Methods. Retrospective, comparative study. The newly diagnosed nAMD patients who were treated with intravitreal bevacizumab or ranibizumab on an as-needed treatment regimen were included in the study. Main outcome measures were the change in best corrected visual acuity (BCVA), and central retinal thickness (CRT). Secondary outcome measures were the number of injections, and complications. Results. A total of 154 patients were included in the study. Bevacizumab group consisted of 79 patients, and ranibizumab group consisted of 74 patients. Mean follow-up time was 18.9 months, and 18.3 months in the bevacizumab and ranibizumab groups, respectively. There was not a significant difference between the two groups regarding the change in BCVA and CRT at all time points (P > 0.05 for all). The mean number of injections at month 12 was 4.8 and 4.7 in bevacizumab and ranibizumab groups, respectively (P > 0.05). No serious complications were detected in any of the groups. Conclusion. Both of the bevacizumab and ranibizumab found to be effective in the treatment of nAMD in regards of functional and anatomical outcomes with similar number of treatments and similar side effects.

Is spectral-domain optical coherence tomography essential for flexible treatment regimens with ranibizumab for neovascular age-related macular degeneration?

Purpose. To evaluate the ability of spectral-domain optical coherence tomography to detect subtle amounts of retinal fluid when the choroidal neovascularization is detected as inactive via time-domain optical coherence tomography and clinical examination in neovascular age-related macular degeneration (nAMD) patients. Methods. Forty-nine eyes of 49 patients with nAMD after ranibizumab treatment were included in this cross-sectional, prospective study. All patients were imaged with TD-OCT and SD-OCT at the same visit one month after a ranibizumab injection. The presence of subretinal, intraretinal, and subretinal pigment epithelium fluid (subRPE) in SD-OCT was evaluated; also mean central retinal thickness (CRT) and the rate of vitreoretinal surface disorders detected via the two devices were evaluated. Results. The mean CRT via TD-OCT and SD-OCT was 218.1 ± 51.3 and 325.7 ± 78.8 microns. Sixteen patients (32.6%) showed any kind of retinal fluid via SD-OCT. In detail, 8 patients (16.3%) showed subretinal fluid, 10 patients (20.4%) showed intraretinal fluid, and 3 patients (6.1%) showed SubRPE fluid. The ability of detecting vitreoretinal surface disorders was comparable between the two devices, except vitreomacular traction. Conclusion. SD-OCT is essential for the nAMD patients who are on an as-needed treatment regimen with ranibizumab. Only TD-OCT and clinical examination may cause insufficient treatment in this group of patients.

Antiangiogenic therapy for ischemic retinopathies

Neovascularization is a common pathological process in various retinal vascular disorders including diabetic retinopathy (DR), age-related macular degeneration (AMD) and retinal vein occlusion (RVO). The development of neovascular vessels may lead to complications such as vitreous hemorrhage, fibrovascular tissue formation, and traction retinal detachments. Ultimately, irreversible vision loss may result. Various proangiogenic factors are involved in these complex processes. Different antiangiogenic drugs have been formulated in an attempt treat these vascular disorders. One factor that plays a major role in the development of retinal neovascularization is vascular endothelial growth factor (VEGF). Anti-VEGF agents are currently FDA approved for the treatment of AMD and RVO. They are also extensively used as an off-label treatment for diabetic macular edema (DME), proliferative DR, and neovascular glaucoma. However, at this time, the long-term safety of chronic VEGF inhibition has not been extensively evaluated. A large and rapidly expanding body of research on angiogenesis is being conducted at multiple centers across the globe to determine the exact contributions and interactions among a variety of angiogenic factors in an effort to determine the therapeutic potential of antiangiogenic agent in the treatment of a variety of retinal diseases.

Short-term progression of wet AMD and correlation with 1-year treatment results

PURPOSE

Quantification of short-term progression of active neovascular age-related macular degeneration and correlation with 1-year outcome.

METHODS

Sixty-five patients with newly diagnosed treatment-naive active subfoveal choroidal neovascularization (CNV), who had participated in clinical trials testing anti-vascular endothelial growth factor therapy, were retrospectively assessed. Early Treatment Diabetic Retinopathy Study best-corrected visual acuity (BCVA), Spectral Domain Optical Coherence Tomography (SD-OCT) and fluorescein angiography (FA) were performed twice during the pretreatment period. Changes in BCVA, central retinal thickness (CRT), average macular thickness (AMT) and leakage area were documented within this pretreatment period for all patients and for lesion type I (occult CNV, n=42) and type II (classic CNV, n=23). Three-month and 1-year BCVA were then correlated with the pretreatment period.

RESULTS

The pretreatment period was 19±3 days (range: 2-108). Neither type I nor type II lesions showed a significant BCVA decrease or CRT/AMT increase during this period. On FA, mean leakage area increased significantly during the pretreatment period: in the pooled group from 5.50±0.62 (screening) to 7.60±0.86 mm2 (baseline) (p<0.0001), in type II from 4.65±0.90 to 7.83±1.62 mm2 (p<0.01) and in type I from 6.08±0.85 to 7.45±0.96 mm2 (p<0.0001). The mean increase in leakage area per day was 0.046±0.02 mm2, p=0.034. Type II showed a daily growth of 0.09±0.08 mm2 (p<0.042) and type I 0.045±0.008 mm2 per day (p<0.0001). However, neither leakage area increase nor pretreatment period was correlated with 3-month or 1-year BCVA outcome.

CONCLUSIONS

SD-OCT and BCVA testing did not reveal deterioration during the pretreatment period. However, the leakage area progressed rapidly. Despite the rapid increasing leakage area, the 19-day waiting period was not associated with a poorer visual outcome at 3 months and 1 year.

The role of spectral-domain OCT in the diagnosis and management of neovascular age-related macular degeneration

Spectral-domain optical coherence tomography (SD-OCT) has emerged as the ancillary examination of choice to assist the diagnosis and management of neovascular age-related macular degeneration (AMD). SD-OCT provides more detailed images of intraretinal, subretinal, and subretinal pigment epithelium fluid when compared to time-domain technology, leading to higher and earlier detection rates of neovascular AMD activity. Improvements in image analysis and acquisition speed make it important for decision-making in the diagnosis and treatment of this disease. However, this new technology needs to be validated for its role in the improvement of visual outcomes in the context of anti-angiogenic therapy.

One-year outcomes of less frequent bevacizumab in age-related macular degeneration

PURPOSE

To evaluate whether a less frequent bevacizumab dosing schedule after repeated doses in short intervals would be effective in patients with subfoveal choroidal neovascularization secondary to age-related macular degeneration.

METHODS

Twenty-seven treatment-naive eyes of patients with subfoveal choroidal neovascularization secondary to age-related macular degeneration participated in this prospective, noncomparative, and interventional study at the Ulucanlar Eye Training and Research Hospital retina clinic. All lesion types were included. Intravitreal injections (1.25 mg/0.05 mL) of bevacizumab were given with a 6-week interval (Day 0, 6 weeks, and 12 weeks) for 3 months and then given at every 12-week interval up to 48 weeks. Main outcome measures of treatment were mean change in visual acuity and foveal center point retinal thickness from baseline documented by optical coherence tomography at 6, 12, 24, 36, and 48 weeks. The effects of patient age, baseline visual acuity, lesion composition, and lesion size on final visual acuity and loss of <15 letters of logarithm of the minimum angle of resolution (logMAR) at 48 weeks were also assessed.

RESULTS

Of the 27 eyes, 24 eyes of 24 patients (14 men and 10 women) completed the 48-week follow-up and study protocol. Compared with baseline (0.95 ± 0.27 on Early Treatment Diabetic Retinopathy Study charts), mean best-corrected visual acuity improved to 0.77 ± 0.21 logMAR (P < 0.001) at Week 6, to 0.74 ± 0.2 logMAR (P < 0.001) at Week 12, to 0.79 ± 0.257 logMAR (P = 0.03) at Week 24, to 0.85 ± 0.26 logMAR (P = 0.54) at Week 36, and to 0.87 ± 0.27 logMAR (P = 1) at Week 48. The baseline mean center point retinal thickness that was 343 ± 64 μm decreased to 236 ± 40 μm (P < 0.001) at Week 6, to 222 ± 39 μm (P < 0.001) at Week 12, to 237 ± 37 (P < 0.001) at Week 24, to 253 ± 44 μm (P < 0.001) at Week 36, and to 268 ± 58 μm (P = 0.002) at Week 48. The maximal visual benefit obtained during the frequent dosing schedule significantly decreased by doses every 12 weeks at 48 weeks (P < 0.001). This decline in the best-corrected visual acuity gain was associated with an increase in the mean center point retinal thickness on optical coherence tomography. Patients aged <70 years and those having a baseline vision of 20/200 or worse were more likely to gain vision at 48 weeks (P = 0.001 and P = 0.02, respectively). In addition, a lesion ≤ 4 disk areas at baseline was less likely to lose <15 letters from baseline at 48 weeks (P = 0.03). No serious ocular and nonocular adverse events were noted.

CONCLUSION

Although intravitreal bevacizumab administration on a schedule of a 6-week injection interval for 3 months followed by every 12-week interval for neovascular age-related macular degeneration provided an improvement or stabilization in best-corrected visual acuity with anatomical improvement. This dosing strategy is unable to maintain the visual acuity and optical coherence tomography benefits seen with more frequent dosing.

Diarylheptanoid 7-(3,4 dihydroxyphenyl)-5-hydroxy-1-phenyl-(1E)-1-heptene from Curcuma comosa Roxb. protects retinal pigment epithelial cells against oxidative stress-induced cell death

Chronic exposure to oxidative stress causes damage to retinal pigment epithelial cells which may lead to the development of age-related macular degeneration, the major cause of vision loss in humans. Anti-oxidants provide a natural defense against retinal cell damage. The present study was designed to evaluate the potential anti-oxidant activity and protective effect of two diarylheptanoids isolated from a medicinal herb Curcuma comosa; 7-(3,4 dihydroxyphenyl)-5-hydroxy-1-phenyl-(1E)-1-heptene (compound A), and 1,7-diphenyl-4(E),6(E)-heptadien-3-ol (compound B) against oxidative stress (H(2)O(2))-induced human retinal pigment epithelial (APRE-19) cell death. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay indicated that the anti-oxidant activity (IC(50)) of compound A was similar to that of vitamin C. Pre-treatment of ARPE-19 cells with 20 μM compound A for 4h afforded greater protection against the insult from 500 μM H(2)O(2), compared to a similar protection period for compound B. Compound A lowered H(2)O(2)-induced lipid peroxidation, malondialdehyde formation and intracellular reactive oxygen species. Furthermore, compound A ameliorated the H(2)O(2)-induced decrease in anti-oxidant enzyme activities and subsequent apoptotic cell death in ARPE-19 cells in a dose and time-dependent manner. These results suggest that compound A protects ARPE-19 cells against oxidative stress, in part, by enhancing several anti-oxidant defense mechanisms. Therefore, compound A may have therapeutic potential for diseases associated with oxidative stress, particularly degenerative retinal diseases.

Multifunctional microbubbles for image-guided antivascular endothelial growth factor therapy

We synthesize multifunctional microbubbles (MBs) for targeted delivery of antivascular endothelial growth factor (antiVEGF) therapy with multimodal imaging guidance. Poly-lactic-co-glycolic acid (PLGA) MBs encapsulating Texas Red dye are fabricated by a modified double-emulsion process. Simultaneous ultrasound and fluorescence imaging are achieved using Texas Red encapsulated MBs. The MBs are conjugated with Avastin, an antiVEGF antibody for treating neovascular age-related macular degeneration (AMD). The conjugation efficiency is characterized by enzyme-linked immunosorbent assay (ELISA). The efficiency for targeted binding of Avastin-conjugated MBs is characterized by microscopic imaging. Our work demonstrates the technical potential of using multifunctional MBs for targeted delivery of antiVEGF therapy in the treatment of exudative AMD.

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.

Management of neovascular age-related macular degeneration

Neovascular age-related macular degeneration (AMD) is becoming an increasing socio-medical problem as the proportion of the aged population is continuously increasing. However, new insights in the pathogenesis of the disease offer the opportunity to develop targeted therapies that attack the disease process more successfully than ever. This review article will focus on summarizing the actual options in the management of neovascular AMD and provide a short overview about recent therapeutic options in clinical and preclinical evaluation. The recent development of anti-VEGF substances for use in clinical routine has markedly improved the prognosis of patients with neovascular AMD. Intravitreal treatment with substances targeting all isotypes of vascular endothelial growth factor (VEGF), for the first time in the history of AMD treatments, results in a significant increase in visual acuity in patients with neovascular AMD. Overall, anti-angiogenic approaches provide vision maintenance in over 90% and substantial improvement in 25-40% of patients. The combination with occlusive therapies like photodynamic therapy (PDT) potentially offers a reduction of re-treatment frequency and long-term maintenance of the treatment benefit. Further developments interacting with various steps in the angiogenic cascade are under clinical or preclinical evaluation and may soon become available. Nevertheless, the growing number of novel therapeutic options will have to provide proof of concept in randomized controlled clinical trials, a major challenge in view of the rapidly evolving field. For those therapies, which are already in clinical use, reasonable diagnostic tools for follow-up need to be developed, as the burden of continuous clinical monitoring of all patients and all indications is significant for patients and doctors. Ultimately, economic issues will be the limiting factor for the clinical availability of different treatment options.

The role of radiation therapy in benign diseases

Although adequate prospective data are lacking, radiation therapy seems to be effective for many benign diseases and remains one of the treatment modalities in the armamentarium of medical professionals. Just as medication has potential adverse effects, and surgery has attendant morbidity, irradiation sometimes can be associated with acute and chronic sequelae. In selecting the mode of treatment, most radiation oncologists consider the particular problem to be addressed and the goal of therapy in the individual patient. It is the careful and judicial use of any therapy that identifies the professional. With an understanding of the current clinical data, treatment techniques, cost, and potential detriment, the goal is to provide long-term control of the disease while minimizing unnecessary treatment and potential risks of side effects. The art lies in balancing benefits against risks.

The end of submacular surgery for age-related macular degeneration? A meta-analysis

BACKGROUND

The aim of this meta-analysis was to summarize and to discuss the results of the four main submacular surgical procedures for age-related macular degeneration (AMD) as reported in the literature through 2004 and to compare them to the Submacular Surgery Trials (SST) data.

METHODS

The existing data in the literature on submacular surgery for AMD from 1992 to 2004 were evaluated. The main outcomes were proportion of patients with two or more lines of improvement in visual acuity (VA) and proportion with two or more lines of deterioration in VA after surgery.

RESULTS

Eighty-eight studies including 1,915 cases met the inclusion criteria. Estimates for the treatment outcome within the four groups of treatment based on a logistic regression model gave comparable results for removal of choroidal neovascularization (CNV) (improvement of VA 28%, deterioration of VA 25%), macular translocation (improvement of VA 31%, deterioration of VA 27%), and for transplantation of pigment epithelium (improvement of VA 22%, deterioration of VA 21%). Estimates for removal of subretinal hemorrhage were significantly different (improvement of VA 62%, deterioration of VA 13%).

CONCLUSIONS

Selected case series showed superior results of VA compared to the SST. The question of whether this is due to selection bias that seems inevitable when dealing with medium-sized nonrandomized case series or due to better results in single centers cannot be answered. In our opinion there still seem to be indications for submacular surgery such as in patients with AMD with low preoperative VA due to large hemorrhagic or fibrotic membranes or nonresponders to photodynamic therapy (PDT).

Synthesis and Anti-tumor Activity of a Fluorinated Analog of Medroxyprogesterone Acetate (MPA), 9.ALPHA.-Fluoromedroxyprogesterone Acetate (FMPA)

We synthesized 9alpha-fluoromedroxyprogesterone acetate (FMPA) in order to test whether it is a more potent anti-angiogenic agent than medroxyprogesterone acetate (MPA), which has been widely used as a therapeutic agent for breast and endometrium cancers. FMPA was previously synthesized in 10 steps (total yield: 1%). An efficient synthesis of FMPA has been achieved in 6 steps (total yield: 12%). We examined the anti-tumor effect of FMPA, complexed with dimethyl-beta-cyclodextrin (DM-beta-CyD), on rat mammary carcinomas induced by 7,12-dimethylbenz[a]anthracene (DMBA). FMPA showed great anti-tumor effect on DMBA-induced rat mammary carcinomas.

Suppression of Laser-Induced Choroidal Neovascularization by Subconjunctival Injection of 9.ALPHA.-Fluoromedroxyprogesterone Acetate (FMPA), an Anti-angiogenic Agent, in Rats

9alpha-Fluoromedroxyprogesterone acetate (FMPA) is a synthetic analog of medroxyprogesterone acetate (MPA). FMPA exhibited more potent anti-tumor and anti-angiogenic activities in some assay systems than the parent agent, MPA. Exudative age-related macular degeneration (AMD) is characterized by choroidal neovascularization (CNV). Anecortave acetate, an angiostatic steroid, is clinically efficacious in patients with exudative AMD. Betamethasone is an anti-angiogenic steroid. Therefore, we examined the effects of FMPA, anecortave acetate and betamethasone on laser-induced CNV in rats. Anecortave acetate and betamethasone were included as positive controls. Crypton laser was applied to the fundus in Brown Norway rats. Laser photocoagulations were performed in each eye between the major retinal vessels of the superior retina. Subconjunctival injection of FMPA, anecortave acetate or betamethasone was performed once just after the photocoagulation (on day 0). The incidence of CNV formation was evaluated by fluorescein angiography (FAG) on day 14. On the next day, examination of the retinal function was performed by electro retinogram (ERG). Subconjunctival injection of FMPA at doses of 300, 1000 and 3000 microg/eye dose-dependently inhibited the incidence of CNV formation. Significant differences were observed at doses of 1000 and 3000 microg/eye of FMPA as compared with the control group. Anecortave acetate and betamethasone significantly inhibited the incidence of CNV formation. FMPA at the doses used in this study did not affect the retinal function in rats, as determined by ERG. FMPA appeared to be effective in a rat model of CNV, so it was demonstrated that FMPA might be useful in the treatment of AMD.

SUPPRESSION OF LASER-INDUCED CHOROIDAL NEOVASCULARIZATION BY POSTERIOR SUB-TENON ADMINISTRATION OF TRIAMCINOLONE ACETONIDE

PURPOSE

To evaluate the inhibitory effect of triamcinolone acetonide (TA) on choroidal neovascularization (CNV) by posterior sub-Tenon administration using a laser-induced CNV model in the rat.

METHODS

Experimental CNV was induced by laser photocoagulation in Brown-Norway male rats. Experimental eyes received posterior sub-Tenon administration of either 2 mg (n = 10) or 0.5 mg (n = 8) of TA. Control eyes (n = 10) received posterior sub-Tenon administration of isotonic sodium chloride solution. Two weeks after treatment, CNV was evaluated by fluorescein angiography and histopathological examination. Concentrations of TA in the vitreous, retina, and choroid were determined by high-performance liquid chromatography at 3 and 7 days after posterior sub-Tenon administration.

RESULTS

The eyes treated with 2 mg of TA showed statistically significant inhibition of fluorescein leakage by fluorescein angiography, as compared with control eyes and eyes treated with 0.5 mg of TA (P < 0.01). The thickness of CNV membranes in eyes treated with 2 mg of TA also decreased statistically significantly, as compared with control eyes (P < 0.01). TA was detected in the vitreous, retina, and choroid 3 days after administration and in the choroid 7 days after administration.

CONCLUSIONS

Posterior sub-Tenon administration of TA may be useful to treat CNV.

Gamma knife surgery for choroidal neovascularization in age-related macular degeneration

The authors conducted a study to determine a way of overcoming the poor-quality demonstration of choroidal neovascularization (CNV) associated with age-related macular degeneration (AMD) on conventional magnetic resonance (MR) imaging studies.

The poor MR imaging demonstration of CNV in patients with AMD makes the use of gamma knife surgery more difficult. This difficulty, however, can be overcome by use of a modified time-of-flight MR imaging sequence with Gd enhancement and coronal reconstruction.

Gamma knife surgery for choroidal neovascularization in age-related macular degeneration

The authors conducted a study to determine a way of overcoming the poor-quality demonstration of choroidal neovascularization (CNV) associated with age-related macular degeneration (AMD) on conventional magnetic resonance (MR) imaging studies.

The poor MR imaging demonstration of CNV in patients with AMD makes the use of gamma knife surgery more difficult. This difficulty, however, can be overcome by use of a modified time-of-flight MR imaging sequence with Gd enhancement and coronal reconstruction.

The local cone and rod system function in early age-related macular degeneration

To compare cone and rod system function in patients with early age- related macular degeneration (ARMD) and control group using multifocal electroretinogram (MERG) and perimetry, to investigate whether there is rod system dysfunction in the central retina in ARMD. Cone-mediated MERG, photopic sensitivity, rod-mediated MERG, and scotopic sensitivity in 16 eyes of control subjects and 24 eyes of early dry-form ARMD were measured with VERIS Science 4.0 and Octopus 101 perimetry. The latencies and average response densities of the summed responses and five ring retinal regions, average sensitivity of all locus and eight ring retinal regions in control eyes were compared with those in ARMD. Mean scotopic and photopic sensitivity of ARMD patients were significantly lower than that of normal controls. Sotopic sensitivity reduced more than photopic sensitivity and the greatest deficit was 2.5-5.0 degrees. The amplitudes of N1 and P1 wave in one ring (5.0 degrees) of rod MERG were significantly lower of ARMD patients than that of normal subjects. Our results suggest that rod function decreased and the parafoveal rod cells were predominantly damaged in ARMD. The rod function testing in macula may be a useful tool to diagnose and measure the fundus dysfunction of ARMD.

The role of the carotenoids, lutein and zeaxanthin, in protecting against age-related macular degeneration: a review based on controversial evidence

PURPOSE

A review of the role of the carotenoids, lutein and zeaxanthin, and their function in altering the pathogenesis of age-related macular degeneration (AMD).

METHODS

Medline and Embase search.

RESULTS

Recent evidence introduces the possibility that lutein and zeaxanthin, carotenoids found in a variety of fruits and vegetables may protect against the common eye disease of macular degeneration. This potential and the lack to slow the progression of macular degeneration, has fueled high public interest in the health benefits of these carotenoids and prompted their inclusion in various supplements. The body of evidence supporting a role in this disease ranges from basic studies in experimental animals to various other clinical and epidemiological studies. Whilst some epidemiological studies suggest a beneficial role for carotenoids in the prevention of AMD, others are found to be unrelated to it. Results of some clinical studies indicate that the risk for AMD is reduced when levels of the carotenoids are elevated in the serum or diet, but this correlation is not observed in other studies. Published data concerning the toxicity of the carotenoids or the optimum dosage of these supplements is lacking.

CONCLUSION

An intake of dietary supplied nutrients rich in the carotenoids, lutein and zeaxanthin, appears to be beneficial in protecting retinal tissues, but this is not proven. Until scientifically sound knowledge is available we recommend for patients judged to be at risk for AMD to: alter their diet to more dark green leafy vegetables, wear UV protective lenses and a hat when outdoors. Future investigations on the role of nutrition, light exposure, genetics, and combinations of photodynamic therapy with intravitreal steroid (triamcinolone-acetonide) injections hold potential for future treatment possibilities.

Adeno-associated virus type-2 expression of pigmented epithelium-derived factor or Kringles 1-3 of angiostatin reduce retinal neovascularization

Neovascular diseases of the retina include age-related macular degeneration and diabetic retinopathy, and together they comprise the leading causes of adult-onset blindness in developed countries. Current surgical, pharmaceutical, and laser therapies for age-related macular degeneration (AMD) rarely result in improved vision, do not significantly prevent neovascularization (NV), and often result in at least some vision loss. To address this therapeutic gap, we determined the efficacy of recombinant adeno-associated viral (rAAV) serotype-2-mediated expression of pigment epithelium-derived factor (PEDF) or Kringle domains 1-3 of angiostatin (K1K3) in reducing aberrant vessel formation in a mouse model of ischemia-induced retinal NV. Both PEDF and K1K3 are potent inhibitors of NV when injected directly, hence expression of these therapeutic factors from rAAV may provide long-term protection from neovascular eye disease. rAAV vectors expressing the therapeutic gene were injected into one eye of postnatal day 0 (P0) newborn mouse pups. Retinal NV was induced in P7 mice by exposure to elevated oxygen for 5 days followed by room air for another five days. Retinal NV was quantified by the number of vascular-endothelial-cell nuclei above the inner-limiting membrane in P17 eyes. The number of such vascular endothelial cell nuclei in eyes treated with rAAV-PEDF or rAAV-K1K3 was significantly reduced (both P < 0.0000002) compared with control eyes. Ocular protein levels detected by ELISA correlate well with the reduction in NV and confirm that expression of antineovascular agents from rAAV vectors may be a therapeutically useful treatment of retinal or choroidal neovascular disease.

Differential retinal angiogenic response to sustained intravitreal release of VEGF and bFGF in different pigmented rabbit breeds

PURPOSE

To determine if two different breeds of pigmented rabbits can demonstrate differences in the degree of inducible angiogenesis within the retina.

METHODS

Non-biodegradable Hydron pellets approximately 1.5 mm in diameter containing both vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) were implanted intravitreally over the optic disk of either Dutch belt rabbits or New Zealand White/Black satin cross rabbits. Control animals from both groups were implanted with blank Hydron pellets. Animals were examined periodically over a 30-day period following implantation. Results were documented by fundus photography and flourescein angiography. Stages of neovascularization (NV) were graded between +1 (preproliferative) and +4 (total NV) with +5 for NV complicated by hemorrhage and/or retinal detachment.

RESULTS

The angiogenic response in the retinas of pigmented NZW/Black satin cross rabbits (N = 5) following implantation of VEGF/bFGF-containing pellets varied extensively from the Dutch belt animals (N = 7). In the Dutch belt rabbits, grading of the angiogenic response demonstrated either +4 or +5 between day 20 and day 30 after implantation. In contrast, the NZW/Black satin cross animals gave a more muted response with a maximum grade of +2 following exposure to the same amount of VEGF and bFGF. Control eyes that received only blank pellets showed no evidence of retinal NV in either the Dutch belts (N = 5) or the NZW/Black satin cross rabbits (N = 5). Statistical analysis showed a significant interaction effect for breed and pellet type (F = 44.85 with 1 df, p < 0.00005), indicating a difference between the breeds in the angiogenic response to the pellet. Moreover, both the NZW/BSC and Dutch belt rabbits displayed a significant increase in angiogenesis with the VEGF/bFGF pellet in comparison to the blank pellet (p = 0.037 and p < 0.00005, respectively).

CONCLUSIONS

These studies indicate that two different breeds of pigmented rabbits exhibit different angiogenic responses to the same amount of both VEGF and bFGF. Florid retinal NV leading to hemorrhage, fibrovascular membrane formation, and traction retinal detachment occurred in the Dutch belt rabbits while tortuosity and dilatation of existing blood vessels with subsequent regression occurred in the NZW/Black satin cross animals. Such differences in the angio-genic response may be due to differences in the genetic background of these animals. If genetic heteriogeneity exists for angiogenic responses, then understanding the genetic role in the regulation of angiogenesis will lead to the design of more effective anti-angiogenic agents and can provide predictive outcomes of individual responses to therapy.