Justine R. Smith

Sequence- and target-independent angiogenesis suppression by siRNA via TLR3

Clinical trials of small interfering RNA (siRNA) targeting vascular endothelial growth factor-A (VEGFA) or its receptor VEGFR1 (also called FLT1), in patients with blinding choroidal neovascularization (CNV) from age-related macular degeneration, are premised on gene silencing by means of intracellular RNA interference (RNAi). We show instead that CNV inhibition is a siRNA-class effect: 21-nucleotide or longer siRNAs targeting non-mammalian genes, non-expressed genes, non-genomic sequences, pro- and anti-angiogenic genes, and RNAi-incompetent siRNAs all suppressed CNV in mice comparably to siRNAs targeting Vegfa or Vegfr1 without off-target RNAi or interferon-α/β activation. Non-targeted (against non-mammalian genes) and targeted (against Vegfa or Vegfr1) siRNA suppressed CNV via cell-surface toll-like receptor 3 (TLR3), its adaptor TRIF, and induction of interferon-γ and interleukin-12. Non-targeted siRNA suppressed dermal neovascularization in mice as effectively as Vegfa siRNA. siRNA-induced inhibition of neovascularization required a minimum length of 21 nucleotides, a bridging necessity in a modelled 2:1 TLR3–RNA complex. Choroidal endothelial cells from people expressing the TLR3 coding variant 412FF were refractory to extracellular siRNA-induced cytotoxicity, facilitating individualized pharmacogenetic therapy. Multiple human endothelial cell types expressed surface TLR3, indicating that generic siRNAs might treat angiogenic disorders that affect 8% of the world’s population, and that siRNAs might induce unanticipated vascular or immune effects.

Differential efficacy of tumor necrosis factor inhibition in the management of inflammatory eye disease and associated rheumatic disease

OBJECTIVE To evaluate the clinical usefulness of tumor necrosis factor (TNF) inhibitors in patients with inflammatory eye disease that is resistant to conventional immunosuppressive therapies. METHODS Sixteen patients (4 males and 12 females aged 7 to 78 years) who received etanercept (n = 14) or infliximab (n = 2) for either inflammatory eye disease or associated joint disease were studied retrospectively to determine the effect of these medications on their ocular inflammation. RESULTS Nine cases of uveitis and 7 cases of scleritis were treated. Systemic diagnoses included rheumatoid arthritis (n = 8), juvenile rheumatoid arthritis (n = 3), ankylosing spondylitis (n = 1), and psoriatic spondylarthropathy (n = 1). Three patients had uveitis without associated systemic disease. Although 12 of 12 patients with active articular inflammation (100%) experienced improvement in joint disease, only 6 of 16 with ocular inflammation (38%) experienced improvement in eye disease. Five patients developed inflammatory eye disease for the first time while taking a TNF inhibitor. No patient discontinued treatment because of adverse drug effects. CONCLUSION TNF inhibitors are well tolerated immunosuppressive medications that may benefit certain subgroups of patients with inflammatory eye disease, but they appear to be more effective in controlling associated inflammatory arthritis.

Persistence of Ebola Virus in Ocular Fluid during Convalescence

Among the survivors of Ebola virus disease (EVD), complications that include uveitis can develop during convalescence, although the incidence and pathogenesis of EVD-associated uveitis are unknown. We describe a patient who recovered from EVD and was subsequently found to have severe unilateral uveitis during convalescence. Viable Zaire ebolavirus (EBOV) was detected in aqueous humor 14 weeks after the onset of EVD and 9 weeks after the clearance of viremia.

Role of intravitreal methotrexate in the management of primary central nervous system lymphoma with ocular involvement

PURPOSE To evaluate the safety and efficacy of intravitreal methotrexate in the management of primary central nervous system lymphoma (PCNSL) involving the eye. DESIGN Retrospective noncomparative interventional case series. PARTICIPANTS Sixteen human immunodeficiency virus-negative white patients (5 males and 11 females, aged 30-76 years) with intraocular B cell lymphoma treated with intravitreal methotrexate at Oregon Health & Science University or Hadassah University Hospital between August 1995 and September 2000. INTERVENTION Patients were treated with intravitreal methotrexate (400 micro g/0.1 ml) according to a standard induction-consolidation-maintenance regimen and monitored by serial examinations, including measurement of visual acuity, slit-lamp biomicroscopy, and dilated funduscopy. MAIN OUTCOME MEASURES Clinical response to intravitreal chemotherapy, number of injections for clinical remission, visual acuity, complications during study period, length of survival from diagnosis, and cause of death. RESULTS Time of follow-up from commencement of the methotrexate injections was 6 to 35 months (median, 18.5 months). Twenty-six of 26 eyes (100%) were cleared clinically of malignant cells after a maximum of 12 methotrexate injections. A second remission was induced in three patients, who were treated with a further course of intravitreal chemotherapy after their tumor recurred within the eye. Complications that occurred during the period of treatment and follow-up included cataract (73% of 26 eyes), corneal epitheliopathy (58% of 26 eyes), maculopathy (42% of 26 eyes), vitreous hemorrhage (8% of 26 eyes), optic atrophy (4% of 26 eyes), and sterile endophthalmitis (4% of 26 eyes). No patient had irreversible loss of vision that could be definitely attributed to the intravitreal injection of methotrexate. CONCLUSIONS Intravitreal chemotherapy with methotrexate is effective in inducing clinical remission of intraocular tumor in PCNSL with acceptable morbidity. Further study is indicated to determine whether this approach extends life expectancy.

CCR3 is a target for age-related macular degeneration diagnosis and therapy.

Age-related macular degeneration (AMD), a leading cause of blindness worldwide, is as prevalent as cancer in industrialized nations. Most blindness in AMD results from invasion of the retina by choroidal neovascularisation (CNV). Here we show that the eosinophil/mast cell chemokine receptor CCR3 is specifically expressed in choroidal neovascular endothelial cells in humans with AMD, and that despite the expression of its ligands eotaxin-1, -2 and -3, neither eosinophils nor mast cells are present in human CNV. Genetic or pharmacological targeting of CCR3 or eotaxins inhibited injury-induced CNV in mice. CNV suppression by CCR3 blockade was due to direct inhibition of endothelial cell proliferation, and was uncoupled from inflammation because it occurred in mice lacking eosinophils or mast cells, and was independent of macrophage and neutrophil recruitment. CCR3 blockade was more effective at reducing CNV than vascular endothelial growth factor A (VEGF-A) neutralization, which is in clinical use at present, and, unlike VEGF-A blockade, is not toxic to the mouse retina. In vivo imaging with CCR3-targeting quantum dots located spontaneous CNV invisible to standard fluorescein angiography in mice before retinal invasion. CCR3 targeting might reduce vision loss due to AMD through early detection and therapeutic angioinhibition.

Primary Vitreoretinal Lymphoma: A Report from an International Primary Central Nervous System Lymphoma Collaborative Group Symposium

Primary vitreoretinal lymphoma (PVRL), also known as primary intraocular lymphoma, is a rare malignancy typically classified as a diffuse large B-cell lymphoma and most frequently develops in elderly populations. PVRL commonly masquerades as posterior uveitis and has a unique tropism for the retina and central nervous system (CNS). Over 15% of primary CNS lymphoma patients develop intraocular lymphoma, usually occurring in the retina and/or vitreous. Conversely, 65%-90% of PVRL patients develop CNS lymphoma. Consequently, PVRL is often fatal because of ultimate CNS association. Current PVRL animal models are limited and require further development. Typical clinical findings include vitreous cellular infiltration (lymphoma and inflammatory cells) and subretinal tumor infiltration as determined using dilated fundoscopy, fluorescent angiography, and optical coherent tomography. Currently, PVRL is most often diagnosed using both histology to identify lymphoma cells in the vitreous or retina and immunohistochemistry to indicate monoclonality. Additional adjuncts in diagnosing PVRL exist, including elevation of interleukin-10 levels in ocular fluids and detection of Ig(H) or T-cell receptor gene rearrangements in malignant cells. The optimal therapy for PVRL is not defined and requires the combined effort of oncologists and ophthalmologists. PVRL is sensitive to radiation therapy and exhibits high responsiveness to intravitreal methotrexate or rituximab. Although systemic chemotherapy alone can result in high response rates in patients with PVRL, there is a high relapse rate. Because of the disease rarity, international, multicenter, collaborative efforts are required to better understand the biology and pathogenesis of PVRL as well as to define both diagnostic markers and optimal therapies.

Epidemiology and Course of Disease in Childhood Uveitis

PURPOSE To describe the disease characteristics and visual outcome of pediatric uveitis. DESIGN Retrospective, longitudinal observation. PARTICIPANTS Five hundred twenty-seven pediatric uveitis patients from the National Eye Institute, University of Illinois, Chicago, and Oregon Health Sciences University. METHODS Retrospective chart review. MAIN OUTCOME MEASURES Demographics, uveitis disease characteristics, complications, treatments, and visual outcomes were determined at baseline and at 1-, 3-, 5-, and 10-year time points. RESULTS The patient population was 54% female; 62.4% white, 12.5% black, 2.7% Asian, 2.1% multiracial, and 14.61% Hispanic. Median age at diagnosis was 9.4 years. The leading diagnoses were idiopathic uveitis (28.8%), juvenile idiopathic arthritis-associated uveitis (20.9%), and pars planitis (17.1%). Insidious onset (58%) and persistent duration (75.3%) were most common. Anterior uveitis was predominant (44.6%). Complications were frequent, and cystoid macular edema (odds ratio [OR] 2.94; P = 0.006) and hypotony (OR, 4.54; P = 0.026) had the most significant visual impact. Ocular surgery was performed in 18.9% of patients. The prevalence of legal blindness was 9.23% at baseline, 6.52% at 1 year, 3.17% at 3 years, 15.15% at 5 years, and 7.69% at 10 years. Posterior uveitis and panuveitis had more severe vision loss. Hispanic ethnicity was associated with a higher prevalence of infectious uveitis and vision loss at baseline. CONCLUSIONS The rate and spectrum of vision threatening complications of pediatric uveitis are significant. Prospective studies using standard outcome measures and including diverse populations are needed to identify children most at risk.

Biologic therapies for inflammatory eye disease

The era of biologic medical therapies provides new options for patients with treatment‐resistant inflammatory eye disease. In this review, the authors summarize current published experience in a rapidly progressing clinical field, including the use of biologics, such as the tumour necrosis factor blockers, daclizumab and rituximab, and related agents, interferons and intravenous immunoglobulin, for the treatment of uveitis, scleritis and orbital inflammation. Reports of dramatic recoveries in patients with recalcitrant ocular inflammation who have received such therapies must be balanced against the high cost of biologics and the potential for serious, and at times unanticipated, complications of this treatment.

A role for methotrexate in the management of non-infectious orbital inflammatory disease

AIM To evaluate the clinical usefulness of methotrexate for patients with non-infectious orbital inflammatory disease who fail to respond to systemic corticosteroids and/or orbital irradiation. METHODS The medical records of patients with non-infectious orbital inflammatory disease who were treated with methotrexate at Oregon Health Sciences University between June 1993 and June 2000 were examined. Methotrexate was administered at a median maximum dose of 20 mg per week (range 15–25 mg per week) in conjunction with folate supplementation. Patients were followed with regular ophthalmic examinations, as well as serum liver enzyme levels and blood cell counts. Clinical signs of regression of the orbital inflammation, visual acuity, dosage and duration of methotrexate therapy, requirement for concurrent corticosteroid administration, and adverse drug reactions were recorded. RESULTS The study cohort included 14 patients (24 eyes) with diagnoses including non-specific orbital inflammation (n=7), Tolosa-Hunt syndrome (n=1), thyroid orbitopathy (n=3), Wegeners granulomatosis (n=1), sarcoidosis (n=1), and Erdheim-Chester disease (n=1). In all cases, methotrexate was commenced as a corticosteroid sparing agent. 10 patients (71%) completed a 4 month therapeutic trial of methotrexate. Median duration of treatment for the nine (64%) patients who experienced clinical benefit was 25 months (range 10–47 months). Six responders were ultimately able to cease methotrexate, including the single patient who required concurrent long term corticosteroid therapy. Complications included fatigue, gastrointestinal disturbance, hair thinning and mild, reversible serum liver enzyme elevation. Two patients (14%) discontinued treatment because of adverse effects. CONCLUSION Methotrexate is a well tolerated immunosuppressive medication which may benefit patients with recalcitrant non-infectious orbital inflammatory disease.

BASIC PATHOGENIC MECHANISMS OPERATING IN EXPERIMENTAL MODELS OF ACUTE ANTERIOR UVEITIS

Acute anterior uveitis is a recurrent inflammatory disease of the eye that occurs commonly, is distressing for the patient, and may have potentially blinding sequelae. The pathogenesis of the disease is poorly understood, and anti‐inflammatory treatment is consequently non‐specific and may be associated with significant complications. Animal models are a possible key to a better understanding of this disease. In one model, rats and mice develop a relatively short‐lived anterior uveal inflammation almost immediately after systemic injection of bacterial endotoxin. Accumulating evidence suggests that cytokine production by resident uveal macrophages initiates endotoxin‐induced uveitis which is characterized by an infiltration of neutrophils and mononuclear cells. A second model displays features in keeping with a delayed‐type hypersensitivity immune response. Experimental melanin‐induced uveitis is an acute recurrent uveitis with delayed onset but extended duration, observed when rats are immunized with bovine ocular melanin. Both animal models have clinical features in common with acute anterior uveitis, although experimental melanin‐induced uveitis appears to mimic the human disease more closely. Novel treatment options to target implicated inflammatory cells and molecules are currently under consideration.