Sharon D. Solomon

Ranibizumab for macular edema due to retinal vein occlusions: implication of VEGF as a critical stimulator.

Macular edema is a major cause of vision loss in patients with central retinal vein occlusion (CRVO) or branch retinal vein occlusion (BRVO). It is not clear how much of the edema is due to hydrodynamic changes from the obstruction and how much is due to chemical mediators. Patients with macular edema due to CRVO (n = 20) or BRVO (n = 20) were randomized to receive three monthly injections of 0.3 or 0.5 mg of ranibizumab. At the primary endpoint, month 3, the median improvement in letters read at 4 m was 17 in the 0.3-mg group and 14 in the 0.5-mg group for CRVO, and 10 and 18, respectively for the BRVO group. Optical coherence tomography (OCT) showed that compared to injections of 0.3 mg, injections of 0.5 mg of ranibizumab tended to cause more rapid reductions of central retinal thickening that lasted longer between injections, but in 3 months, excess central retinal thickening which is a quantitative assessment of the macular edema, was reduced by approximately 90% in all four treatment groups. There was no correlation between the amount of improvement and duration of disease or patient age at baseline, but there was some correlation between the aqueous vascular endothelial growth factor (VEGF) level at baseline and amount of improvement. These data indicate that excess production of VEGF in the retinas of patients with CRVO or BRVO is a major contributor to macular edema and suggest that additional studies investigating the efficacy of intraocular injections of ranibizumab are needed.

Racial Differences in the Prevalence of Age-Related Macular Degeneration: The Salisbury Eye Evaluation (SEE) Project

OBJECTIVE To determine differences in the prevalence of age-related macular degeneration (AMD) and its fundus manifestations in a population-based sample of older black and white Americans. DESIGN Cross-sectional population-based study of 2520 participants of whom 1854 are white and 666 are black. Mean age was 73.5 years. Stereoscopic color fundus photographs were graded for presence, severity, and location of drusen, retinal pigment epithelium abnormalities, and choroidal neovascularization or disciform scarring. RESULTS Drusen at least 64 microm in size were identified in 56% of black and white individuals within 3000 microm of the foveal center, but drusen larger than 125 microm were more common among white participants (16% white vs 11% black individuals). Drusen at least 250 microm in size, confluent drusen, or a larger area (> 10%) occupied by drusen were each more common among white participants. White individuals were 3 times more likely to have focal hyperpigmentation than black individuals. Racial differences were most pronounced for features within the central 1500-microm macular zone. Neovascular AMD was present in 1.7% of white participants and 1.1% of black participants (age-adjusted, P = .38), whereas geographic atrophy was more common in white than black individuals (1.8% vs 0.3%; age-adjusted, P = .02). CONCLUSIONS White persons are generally more likely than black persons to have medium or large drusen, focal pigment abnormalities, and advanced AMD. Racial differences were prominent for nonneovascular AMD features only when present in the central zone. These data suggest that black individuals may have a mechanism for protection in the central zone against these critical fundus features, which themselves convey high risk of progression to advanced AMD.

Antagonism of vascular endothelial growth factor for macular edema caused by retinal vein occlusions: two-year outcomes.

PURPOSE To determine the long-term effects of intraocular antagonism of vascular endothelial growth factor (VEGF) in patients with macular edema caused by retinal vein occlusions (RVOs). DESIGN Prospective randomized trial. PARTICIPANTS Twenty patients with macular edema caused by branch RVOs (BRVOs) and 20 patients with central RVOs (CRVOs). METHODS After the month 3 primary end point, patients were seen every 2 months and received injections of an anti-VEGF agent as needed for recurrent edema. MAIN OUTCOME MEASURES Mean change from baseline best-corrected visual acuity (BCVA) at month 24 with assessment of other parameters of visual function and center subfield thickness (foveal thickness [FTH]). RESULTS For 17 patients with BRVO who completed 2 years of follow-up, the mean improvement from baseline in BCVA at month 24 was 17.8 letters compared with 15.6 letters at month 3. Improvement by at least 6, 3, or 2 lines occurred in 18%, 59%, and 76% of patients, respectively. The Snellen equivalent BCVA at month 24 was 20/40 or better in 10 patients. With an average of 2 injections of ranibizumab during year 2, the mean FTH at month 24 was 245.8 μm compared with 217.1 μm at month 3 and 481.5 μm at baseline. For 14 patients with CRVO who completed 2 years of follow-up, the mean improvement in BCVA at month 24 was 8.5 letters compared with 12.0 letters at month 3. Improvement by at least 6, 3, or 2 lines occurred in 14%, 21%, and 43% of patients, respectively. The Snellen equivalent BCVA at month 24 was 20/40 or better in 4 patients. With an average of 3.5 injections of ranibizumab in year 2, mean FTH at month 24 was 338 μm compared with 278 μm at month 3 and 533 μm at baseline. Duration of RVO >1 year at study entry and nonperfusion of perifoveal capillaries for 360 degrees correlated with reduced visual outcomes. CONCLUSIONS Antagonism of VEGF provides substantial long-term benefit to patients with macular edema caused by RVO, but frequent injections are required in some patients with BRVO and most patients with CRVO.

SDH1, the gene encoding the succinate dehydrogenase flavoprotein subunit from Saccharomyces cerevisiae

We describe the isolation, sequence and construction of a disruption of the yeast SDH1 gene, encoding the flavoprotein subunit of succinate dehydrogenase. This is the first eukaryotic flavoprotein subunit-encoding gene to be fully sequenced. The deduced amino acid (aa) sequence is 50% identical to the Escherichia coli enzyme sequence. The yeast gene encodes an N-terminal extension of 45 aa relative to the E. coli sequence which may act as a mitochondrial targeting signal. Disruption of the gene results in the inability to respire, assayed as the inability to utilize the nonfermentable carbon source, glycerol. This is the expected phenotype for disruption of an essential component of the yeast citric acid cycle.

VEGF Secreted by Hypoxic Müller Cells Induces MMP-2 Expression and Activity in Endothelial Cells to Promote Retinal Neovascularization in Proliferative Diabetic Retinopathy

In proliferative diabetic retinopathy (PDR), retinal ischemia promotes neovascularization (NV), which can lead to profound vision loss in diabetic patients. Treatment for PDR, panretinal photocoagulation, is inherently destructive and has significant visual consequences. Therapies targeting vascular endothelial growth factor (VEGF) have transformed the treatment of diabetic eye disease but have proven inadequate for treating NV, prompting exploration for additional therapeutic options for PDR patients. In this regard, extracellular proteolysis is an early and sustained activity strictly required for NV. Extracellular proteolysis in NV is facilitated by the dysregulated activity of matrix metalloproteinases (MMPs). Here, we set out to better understand the regulation of MMPs by ischemia in PDR. We demonstrate that accumulation of hypoxia-inducible factor-1α in Müller cells induces the expression of VEGF, which, in turn, promotes increased MMP-2 expression and activity in neighboring endothelial cells (ECs). MMP-2 expression was detected in ECs in retinal NV tissue from PDR patients, whereas MMP-2 protein levels were elevated in the aqueous of PDR patients compared with controls. Our findings demonstrate a complex interplay among hypoxic Müller cells, secreted angiogenic factors, and neighboring ECs in the regulation of MMP-2 in retinal NV and identify MMP-2 as a target for the treatment of PDR.

Detection of New-Onset Choroidal Neovascularization Using Optical Coherence Tomography: The AMD DOC Study

PURPOSE To determine the sensitivity of time domain optical coherence tomography (OCT) in detecting conversion to neovascular age-related macular degeneration (AMD) in eyes at high risk for choroidal neovascularization (CNV), compared with detection using fluorescein angiography (FA) as the gold standard. DESIGN Prospective, multicenter, observational study. PARTICIPANTS Individuals aged ≥50 years with nonneovascular AMD at high risk of progressing to CNV in the study eye and evidence of neovascular AMD in the fellow eye. METHODS At study entry and every 3 months through 2 years, participants underwent best-corrected visual acuity, supervised Amsler grid testing, preferential hyperacuity perimetry (PHP) testing, stereoscopic digital fundus photographs with FA, and OCT imaging. A central Reading Center graded all images. MAIN OUTCOMES MEASURES The sensitivity of OCT in detecting conversion to neovascular AMD by 2 years, using FA as the reference standard. Secondary outcomes included comparison of sensitivity, specificity, positive predictive value, and negative predictive value of OCT, PHP, and supervised Amsler grid relative to FA for detecting incident CNV. RESULTS A total of 98 participants were enrolled; 87 (89%) of these individuals either completed the 24-month visit or exited the study after developing CNV. Fifteen (17%) study eyes had incident CNV confirmed on FA by the Reading Center. The sensitivity of each modality for detecting CNV was: OCT 0.40 (95% confidence interval [CI], 0.16-0.68), supervised Amsler grid 0.42 (95% CI, 0.15-0.72), and PHP 0.50 (95% CI, 0.23-0.77). Treatment for incident CNV was recommended by the study investigator in 13 study eyes. Sensitivity of the testing modalities for detection of CNV in these 13 eyes was 0.69 (95% CI, 0.39-0.91) for OCT, 0.50 (95% CI, 0.19-0.81) for supervised Amsler grid, and 0.70 (95% CI, 0.35-0.93) for PHP. Specificity of the OCT was higher than that of the Amsler grid and PHP. CONCLUSIONS Time-domain OCT, supervised Amsler grid, and PHP have low to moderate sensitivity for detection of new-onset CNV compared with FA. Optical coherence tomography has greater specificity than Amsler grid or PHP. Among fellow eyes of individuals with unilateral CNV, FA remains the best method to detect new-onset CNV.

Diabetic Retinopathy: A Position Statement by the American Diabetes Association.

Diabetic retinopathy diagnostic assessment and treatment options have improved dramatically since the 2002 American Diabetes Association Position Statement (1). These improvements include the widespread adoption of optical coherence tomography to assess retinal thickness and intraretinal pathology and wide-field fundus photography to reveal clinically silent microvascular lesions. Treatment of diabetic macular edema is now achieved by intravitreous injection of anti–vascular endothelial growth factor agents, and the same drugs are now used for proliferative diabetic retinopathy. Improvements in medications and devices for the systemic therapy of diabetes have also improved the ability of patients to optimize their metabolic control. This Position Statement incorporates these recent developments for the use of physicians and patients. Diabetic retinopathy is a highly specific neurovascular complication of both type 1 and type 2 diabetes, the prevalence of which strongly correlates to both the duration of diabetes and level of glycemic control. A pooled meta-analysis involving 35 studies conducted worldwide from 1980 to 2008 estimated global prevalence of any diabetic retinopathy and proliferative diabetic retinopathy (PDR) among patients to be 35.4% and 7.5%, respectively (2). Diabetic retinopathy is the most frequent cause of new cases of blindness among adults aged 20–74 years in developed countries. Glaucoma, cataracts, and other disorders of the eye occur earlier and more frequently in people with diabetes. In addition to diabetes duration, factors that increase the risk of or are associated with retinopathy include chronic hyperglycemia (3,4), nephropathy (5), hypertension (6), and dyslipidemia (7). Intensive diabetes management with the goal of achieving near-normoglycemia has been shown in large prospective randomized studies to prevent and/or delay the onset and progression of diabetic retinopathy (8,9). Lowering blood pressure has been shown to decrease retinopathy progression in people with type 2 diabetes, although tight targets (systolic blood pressure <120 mmHg) do …

Progression of Age-Related Macular Degeneration After Cataract Surgery

OBJECTIVE To document age-related macular degeneration (AMD) progression after cataract surgery. METHODS Surgeons prospectively enrolled patients with nonneovascular AMD who were awaiting cataract surgery. Fluorescein angiography was performed preoperatively and at the postoperative week 1, month 3, and month 12 visits. Incidence of neovascular AMD development within 12 months after operation was the primary outcome measure. RESULTS A total of 108 subjects were enrolled. Of 86 eyes with preoperatively photographically confirmed nonneovascular AMD, 71 had gradable images by month 12. Neovascular AMD was observed in 9 of 71 eyes (12.7%; 95% confidence interval, 6.0%-22.7%). The progression rate between week 1 and month 12 decreased to 3 of 65 eyes (4.6%; 95% confidence interval, 1.0%-12.9%) after excluding 5 neovascular events identified on the postoperative week 1 visit and 1 case with missing photographs at this visit. CONCLUSION The low incidence rate of neovascular AMD development between 1 week and 1 year after cataract surgery did not support the hypothesis that cataract surgery increases the risk of AMD progression. Several eyes appeared to have disease progression on postsurgery week 1 fluorescein angiograms, suggesting that many cases of presumed progression to neovascular AMD following cataract surgery may have been present prior to cataract surgery, but not recognized owing to lens opacity.

Scatter Photocoagulation Does Not Reduce Macular Edema or Treatment Burden in Patients with Retinal Vein Occlusion The RELATE Trial

PURPOSE To determine whether scatter and grid laser photocoagulation (laser) adds benefit to ranibizumab injections in patients with macular edema from retinal vein occlusion (RVO) and to compare 0.5-mg with 2.0-mg ranibizumab. DESIGN Randomized, double-masked, controlled clinical trial. PARTICIPANTS Thirty-nine patients with central RVO (CRVO) and 42 with branch RVO (BRVO). METHODS Subjects were randomized to 0.5 mg or 2.0 mg ranibizumab every 4 weeks for 24 weeks and re-randomized to pro re nata ranibizumab plus laser or ranibizumab alone. MAIN OUTCOME MEASURES Mean change from baseline best-corrected visual acuity (BCVA) at week 24 for BCVA at weeks 48, 96, and 144 for second randomization. RESULTS Mean improvement from baseline BCVA at week 24 was 15.5 and 15.8 letters in the 0.5-mg and 2.0-mg CRVO groups, and 12.1 and 14.6 letters in the 0.5-mg and 2.0-mg BRVO groups. For CRVO, but not BRVO, there was significantly greater reduction from baseline mean central subfield thickness (CST) in the 2.0-mg versus 0.5-mg group (396.1 vs. 253.5 μm; P = 0.03). For the second randomization in CRVO patients, there was no significant difference from week 24 BCVA in the ranibizumab plus laser versus the ranibizumab only groups at week 48 (-3.3 vs. 0.0 letters), week 96 (+0.69 vs. -1.6 letters), or week 144 (+0.4 vs. -6.7 letters), and a significant increase from week 24 mean CST at week 48 (+94.7 vs. +15.2 μm; P = 0.05) but not weeks 96 or 144. For BRVO, there was a significant reduction from week 24 mean BCVA in ranibizumab plus laser versus ranibizumab at week 48 (-7.5 vs. +2.8; P < 0.01) and week 96 (-2.0 vs. +4.8; P < 0.03), but not week 144, and there were no differences in mean CST change from week 24 at weeks 48, 96, or 144. Laser failed to increase edema resolution or to reduce the ranibizumab injections between weeks 24 and 144. CONCLUSIONS In patients with macular edema resulting from RVO, there was no short-term clinically significant benefit from monthly injections of 2.0-mg versus 0.5-mg ranibizumab injections and no long-term benefit in BCVA, resolution of edema, or number of ranibizumab injections obtained by addition of laser treatment to ranibizumab.

Angiopoietin-like 4 is a potent angiogenic factor and a novel therapeutic target for patients with proliferative diabetic retinopathy.

Significance In proliferative diabetic retinopathy (PDR), the most vision-threatening sequela of diabetic eye disease, retinal ischemia leads to increased expression of angiogenic factors that promote neovascularization. Although therapies targeting the potent angiogenic mediator vascular endothelial growth factor have been remarkably successful for the treatment of diabetic macular edema, this approach has not proven sufficient to prevent the development of retinal neovascularization, implicating additional angiogenic factor(s) in PDR pathogenesis. We demonstrate here that angiopoietin-like 4 is a potent angiogenic mediator with markedly increased expression in the eyes of PDR patients. Our studies identify a novel therapeutic target for the treatment of ocular neovascular disease and may have broad implications for the treatment of other diseases dependent on pathologic angiogenesis. Diabetic eye disease is the most common cause of severe vision loss in the working-age population in the developed world, and proliferative diabetic retinopathy (PDR) is its most vision-threatening sequela. In PDR, retinal ischemia leads to the up-regulation of angiogenic factors that promote neovascularization. Therapies targeting vascular endothelial growth factor (VEGF) delay the development of neovascularization in some, but not all, diabetic patients, implicating additional factor(s) in PDR pathogenesis. Here we demonstrate that the angiogenic potential of aqueous fluid from PDR patients is independent of VEGF concentration, providing an opportunity to evaluate the contribution of other angiogenic factor(s) to PDR development. We identify angiopoietin-like 4 (ANGPTL4) as a potent angiogenic factor whose expression is up-regulated in hypoxic retinal Müller cells in vitro and the ischemic retina in vivo. Expression of ANGPTL4 was increased in the aqueous and vitreous of PDR patients, independent of VEGF levels, correlated with the presence of diabetic eye disease, and localized to areas of retinal neovascularization. Inhibition of ANGPTL4 expression reduced the angiogenic potential of hypoxic Müller cells; this effect was additive with inhibition of VEGF expression. An ANGPTL4 neutralizing antibody inhibited the angiogenic effect of aqueous fluid from PDR patients, including samples from patients with low VEGF levels or receiving anti-VEGF therapy. Collectively, our results suggest that targeting both ANGPTL4 and VEGF may be necessary for effective treatment or prevention of PDR and provide the foundation for studies evaluating aqueous ANGPTL4 as a biomarker to help guide individualized therapy for diabetic eye disease.