Stephen R. Russell

Drusen associated with aging and age-related macular degeneration contain proteins common to extracellular deposits associated with atherosclerosis, elastosis, amyloidosis, and dense deposit disease

Age‐related macular degeneration (AMD), a blinding disorder that compromises central vision, is characterized by the accumulation of extracellular deposits, termed drusen, between the retinal pigmented epithelium and the choroid. Recent studies in this laboratory revealed that vitronectin is a major component of drusen. Because vitronectin is also a constituent of abnormal deposits associated with a variety of diseases, drusen from human donor eyes were examined for compositional similarities with other extracellular disease deposits. Thirty‐four antibodies to 29 different proteins or protein complexes were tested for immunoreactivity with hard and soft drusen phenotypes. These analyses provide a partial profile of the molecular composition of drusen. Serum amyloid P component, apolipoprotein E, immunoglobulin light chains, Factor X, and complement proteins (C5 and C5b‐9 complex) were identified in all drusen phenotypes. Transcripts encoding some of these molecules were also found to be synthesized by the retina, retinal pigmented epithelium, and/or choroid. The compositional similarity between drusen and other disease deposits may be significant in view of the recently established correlation between AMD and atherosclerosis. This study suggests that similar pathways may be involved in the etiologies of AMD and other age‐related diseases.—Mullins, R. F., Russell, S. R., Anderson, D. H., Hageman, G. S. Drusen associated with aging and age‐related macular degeneration contain proteins common to extracellular deposits associated with atherosclerosis, elastosis, amyloidosis, and dense deposit disease. FASEB J. 14, 835–846 (2000)

Automated 3-D Intraretinal Layer Segmentation of Macular Spectral-Domain Optical Coherence Tomography Images

With the introduction of spectral-domain optical coherence tomography (OCT), much larger image datasets are routinely acquired compared to what was possible using the previous generation of time-domain OCT. Thus, the need for 3-D segmentation methods for processing such data is becoming increasingly important. We report a graph-theoretic segmentation method for the simultaneous segmentation of multiple 3-D surfaces that is guaranteed to be optimal with respect to the cost function and that is directly applicable to the segmentation of 3-D spectral OCT image data. We present two extensions to the general layered graph segmentation method: the ability to incorporate varying feasibility constraints and the ability to incorporate true regional information. Appropriate feasibility constraints and cost functions were learned from a training set of 13 spectral-domain OCT images from 13 subjects. After training, our approach was tested on a test set of 28 images from 14 subjects. An overall mean unsigned border positioning error of 5.69 plusmn 2.41 mum was achieved when segmenting seven surfaces (six layers) and using the average of the manual tracings of two ophthalmologists as the reference standard. This result is very comparable to the measured interobserver variability of 5.71 plusmn 1.98 mum.

Risk Factors in Age-related Maculopathy Complicated by Choroidal Neovascularization

We evaluated previously reported and hypothesized risk factors for the development of age-related maculopathy (ARM) in a case-control study. We compared 26 patients with documented disciform scarring or choroidal neovascularization with 23 age- and sex-matched controls. Systolic and diastolic blood pressure, smoking history, glucose, lipoprotein profiles, and serum levels of vitamins A, C, and E did not differ significantly between the two groups. Statistically significant associations (P less than 0.05) identified by univariate analysis include degree of dermal elastotic degeneration in sun-exposed and sun-protected skin, white blood count, increasing age and small posterior lenticular opacities. Using an interactive multivariate model, only extent of elastosis in sun protected dermis, age and white blood count were predictive (Mult R = 0.652, P less than .001). Our data support the concept of a multifactorial etiology of ARM but suggest that generalized increased susceptibility of elastic fibers to photic or other degenerative stimuli is a new and important risk factor for choroidal neovascularization.

Vitronectin is a constituent of ocular drusen and the vitronectin gene is expressed in human retinal pigmented epithelial cells

Age‐related macular degeneration (AMD) leads to dysfunction and degeneration of retinal photoreceptor cells. This disease is characterized, in part, by the development of extracellular deposits called drusen. The presence of drusen is correlated with the development of AMD, although little is known about drusen composition or biogenesis. Drusen form within Bruchs membrane, a stratified extracellular matrix situated between the retinal pigmented epithelium and choriocapillaris. Because of this association, we sought to determine whether drusen contain known extracellular matrix constituents. Antibodies directed against a battery of extracellular matrix molecules were screened on drusen‐containing sections from human donor eyes, including donors with clinically documented AMD. Antibodies directed against vitronectin, a plasma protein and extracellular matrix component, exhibit intense and consistent reactivity with drusen; antibodies to the conformationally distinct, heparin binding form of human vitronectin are similarly immunoreactive. No differences in vitronectin immunoreactivity between hard and soft drusen, or between macular and extramacular regions, have been observed. RT‐PCR analyses revealed that vitronectin mRNA is expressed in the retinal pigmented epithelium (RPE)‐choroidal complex and cultured RPE cells. These data document that vitronectin is a major constituent of human ocular drusen and that vitronectin mRNA is synthesized locally. Based on these data, we propose that vitronectin may participate in the pathogenesis of AMD.—Hageman, G. S., Mullins, R. F., Russell, S. R., Johnson, L. V., Anderson, D. H. Vitronectin is a constituent of ocular drusen and the vitronectin gene is expressed in human retinal pigmented epithelial cells. FASEB J. 13, 477–484 (1999)

Multiscale AM-FM Methods for Diabetic Retinopathy Lesion Detection

In this paper, we propose the use of multiscale amplitude-modulation-frequency-modulation (AM-FM) methods for discriminating between normal and pathological retinal images. The method presented in this paper is tested using standard images from the early treatment diabetic retinopathy study. We use 120 regions of 40 × 40 pixels containing four types of lesions commonly associated with diabetic retinopathy (DR) and two types of normal retinal regions that were manually selected by a trained analyst. The region types included microaneurysms, exudates, neovascularization on the retina, hemorrhages, normal retinal background, and normal vessels patterns. The cumulative distribution functions of the instantaneous amplitude, the instantaneous frequency magnitude, and the relative instantaneous frequency angle from multiple scales are used as texture feature vectors. We use distance metrics between the extracted feature vectors to measure interstructure similarity. Our results demonstrate a statistical differentiation of normal retinal structures and pathological lesions based on AM-FM features. We further demonstrate our AM-FM methodology by applying it to classification of retinal images from the MESSIDOR database. Overall, the proposed methodology shows significant capability for use in automatic DR screening.

Automated Early Detection of Diabetic Retinopathy

PURPOSE To compare the performance of automated diabetic retinopathy (DR) detection, using the algorithm that won the 2009 Retinopathy Online Challenge Competition in 2009, the Challenge2009, against that of the one currently used in EyeCheck, a large computer-aided early DR detection project. DESIGN Evaluation of diagnostic test or technology. PARTICIPANTS Fundus photographic sets, consisting of 2 fundus images from each eye, were evaluated from 16670 patient visits of 16,670 people with diabetes who had not previously been diagnosed with DR. METHODS The fundus photographic set from each visit was analyzed by a single retinal expert; 793 of the 16,670 sets were classified as containing more than minimal DR (threshold for referral). The outcomes of the 2 algorithmic detectors were applied separately to the dataset and were compared by standard statistical measures. MAIN OUTCOME MEASURES The area under the receiver operating characteristic curve (AUC), a measure of the sensitivity and specificity of DR detection. RESULTS Agreement was high, and examination results indicating more than minimal DR were detected with an AUC of 0.839 by the EyeCheck algorithm and an AUC of 0.821 for the Challenge2009 algorithm, a statistically nonsignificant difference (z-score, 1.91). If either of the algorithms detected DR in combination, the AUC for detection was 0.86, the same as the theoretically expected maximum. At 90% sensitivity, the specificity of the EyeCheck algorithm was 47.7% and that of the Challenge2009 algorithm was 43.6%. CONCLUSIONS Diabetic retinopathy detection algorithms seem to be maturing, and further improvements in detection performance cannot be differentiated from best clinical practices, because the performance of competitive algorithm development now has reached the human intrareader variability limit. Additional validation studies on larger, well-defined, but more diverse populations of patients with diabetes are needed urgently, anticipating cost-effective early detection of DR in millions of people with diabetes to triage those patients who need further care at a time when they have early rather than advanced DR.

Anecortave acetate as monotherapy for the treatment of subfoveal lesions in patients with exudative age-related macular degeneration (AMD): interim (month 6) analysis of clinical safety and efficacy.

Purpose To evaluate clinical safety and efficacy of the angiostatic agent anecortave acetate for treatment of subfoveal choroidal neovascularization secondary to AMD. Methods 128 patients were randomized to placebo treatment or one of three anecortave acetate doses. Study medication was administered as a posterior juxtascleral injection onto the posterior scleral surface. Best-corrected logMAR vision was obtained at baseline and follow-up visits. Fluorescein angiograms were evaluated for eligibility before enrollment and posttreatment. Results Six months after a single treatment, visual acuity (mean change from baseline logMAR values) was significantly better (P = 0.003) after anecortave acetate 15 mg than placebo. More patients treated with anecortave acetate 15 mg than placebo maintained vision (88% versus 70%, P = 0.080), especially those with predominantly classic lesions (92% versus 65%, P = 0.021). Anecortave acetate 15 mg inhibited lesion growth significantly better than placebo (P = 0.001). Trends favoring the other doses over placebo were observed for vision preservation and lesion inhibition, but statistical significance was not achieved. The Independent Safety Committee overseeing this study identified no clinically relevant treatment-related changes. Conclusion Anecortave acetate 15 mg is safe and effective for preserving or improving vision and for inhibiting lesion growth in patients with subfoveal AMD.

Efficacy and safety of voretigene neparvovec (AAV2-hRPE65v2) in patients with RPE65-mediated inherited retinal dystrophy: a randomised, controlled, open-label, phase 3 trial

BACKGROUND Phase 1 studies have shown potential benefit of gene replacement in RPE65-mediated inherited retinal dystrophy. This phase 3 study assessed the efficacy and safety of voretigene neparvovec in participants whose inherited retinal dystrophy would otherwise progress to complete blindness. METHODS In this open-label, randomised, controlled phase 3 trial done at two sites in the USA, individuals aged 3 years or older with, in each eye, best corrected visual acuity of 20/60 or worse, or visual field less than 20 degrees in any meridian, or both, with confirmed genetic diagnosis of biallelic RPE65 mutations, sufficient viable retina, and ability to perform standardised multi-luminance mobility testing (MLMT) within the luminance range evaluated, were eligible. Participants were randomly assigned (2:1) to intervention or control using a permuted block design, stratified by age (<10 years and ≥10 years) and baseline mobility testing passing level (pass at ≥125 lux vs <125 lux). Graders assessing primary outcome were masked to treatment group. Intervention was bilateral, subretinal injection of 1·5 × 1011 vector genomes of voretigene neparvovec in 0·3 mL total volume. The primary efficacy endpoint was 1-year change in MLMT performance, measuring functional vision at specified light levels. The intention-to-treat (ITT) and modified ITT populations were included in primary and safety analyses. This trial is registered with ClinicalTrials.gov, number NCT00999609, and enrolment is complete. FINDINGS Between Nov 15, 2012, and Nov 21, 2013, 31 individuals were enrolled and randomly assigned to intervention (n=21) or control (n=10). One participant from each group withdrew after consent, before intervention, leaving an mITT population of 20 intervention and nine control participants. At 1 year, mean bilateral MLMT change score was 1·8 (SD 1·1) light levels in the intervention group versus 0·2 (1·0) in the control group (difference of 1·6, 95% CI 0·72-2·41, p=0·0013). 13 (65%) of 20 intervention participants, but no control participants, passed MLMT at the lowest luminance level tested (1 lux), demonstrating maximum possible improvement. No product-related serious adverse events or deleterious immune responses occurred. Two intervention participants, one with a pre-existing complex seizure disorder and another who experienced oral surgery complications, had serious adverse events unrelated to study participation. Most ocular events were mild in severity. INTERPRETATION Voretigene neparvovec gene replacement improved functional vision in RPE65-mediated inherited retinal dystrophy previously medically untreatable. FUNDING Spark Therapeutics.

Adeno-associated virus type 5: Transduction efficiency and cell-type specificity in the primate retina

Gene transfer using adeno-associated viruses (AAVs) has been effective for treating inherited retinal diseases in animal models. Further evaluation in primates must be performed prior to clinical application, however, because of the difference between the retina of the primate and those of other animals. Prior work has shown that AAV2 can transduce rod-photoreceptor and RPE cells in the non-human primate retina and that AAV5 is more efficient at transducing photoreceptor cells than AAV2 in the rodent retina. In this study, we evaluated the efficiency of AAV5 in the non-human primate retina after subretinal injections of the vector to distinct anatomic retinal regions (superior, inferior, nasal, macula, temporal). rAAV5 led to a rapid onset of transgene expression (within 2 weeks), with expression persisting up to 10 months. Postoperative electrophysiology studies showed that global retinal function was preserved following gene transfer. Quantitative analysis of gene transfer demonstrated a maximum transduction efficiency of 22% in the injected areas. Evaluation of cell types using confocal microscopy and cone-specific antibodies revealed that AAV5, expressing reporter genes from the cytomegalovirus (CMV) promoter/enhancer, preferentially transduced rods. No significant differences were found in the regional tropism of AAV5 among the five areas injected despite variation in retinal topography. Immunohistochemical studies revealed that the AAV5 receptor, PDGFR-A, is localized to the outer segments of rods but not cones providing a basis for the observed tropism. Our results support the utility of AAV5 for rod photoreceptor degeneration therapies.

Direct and Feeder Vessel Photocoagulation of Retinal Angiomas with Dye Yellow Laser

Dye yellow laser photocoagulation (577 nm) was used to treat 14 retinal angiomas in nine patients. Eight patients had von Hippel-Lindau disease. Treatment was applied either directly to the tumor surface or to the feeding artery. Seven of eight angiomas that were treated directly and five of six that had feeder vessel treatment only were ablated successfully using dye yellow laser alone (mean follow-up, 11.1 months). An average of 2.2 treatments for feeder vessel and 1.1 treatments for direct ablation was required. Neither treatment caused decreased vision or severe complications. Dye yellow laser photocoagulation allows for effective treatment of retinal angiomas even when applied to the feeder vessel alone.