Browsing by Subject "Age-related macular degeneration"
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Item Disease progression pathways of wet AMD: opportunities for new target discovery(Taylor & Francis, 2022) Wolf, Amber T.; Harris, Alon; Oddone, Francesco; Siesky, Brent; Verticchio Vercellin, Alice; Ciulla, Thomas A.; Ophthalmology, School of MedicineIntroduction: Age-related macular degeneration (AMD) is the leading cause of irreversible blindness among people age 60 years or older in developed countries. Current standard-of-care anti-vascular endothelial growth factor (VEGF) therapy, which inhibits angiogenesis and vascular permeability, has been shown to stabilize choroidal neovascularization and increase visual acuity in neovascular AMD. However, therapeutic limitations of anti-VEGF therapy include limited durability with consequent need for frequent intravitreal injections, and a ceiling of efficacy. Current strategies under investigation include targeting VEGF-C and VEGF-D, integrins, tyrosine kinase receptors, and the Tie2/angiopoietin-2 pathway. A literature search was conducted through November 30, 2021 on PubMed, Medline, Google Scholar, and associated digital platforms with the following keywords: wet macular degeneration, age-related macular degeneration, therapy, VEGF-A, VEGF-C, VEGF-D, integrins, Tie2/Ang2, and tyrosine kinase inhibitors. Areas covered: The authors provide a comprehensive review of AMD disease pathways and mechanisms involved in wet AMD as well as novel targets for future therapies. Expert opinion: With novel targets and advancements in drug delivery, there is potential to address treatment burden and to improve outcomes for patients afflicted with neovascular AMD.Item Double-Masked, Randomized, Phase 2 Evaluation of Abicipar Pegol (an Anti-VEGF DARPin Therapeutic) in Neovascular Age-Related Macular Degeneration(Mary Ann Liebert, 2018-11-09) Callanan, David; Kunimoto, Derek; Maturi, Raj K.; Patel, Sunil S.; Staurenghi, Giovanni; Wolf, Sebastian; Cheetham, Janet K.; Hohman, Thomas C.; Kim, Kimmie; López, Francisco J.; Schneider, Susan; Ophthalmology, School of MedicinePURPOSE: To evaluate safety and efficacy of the vascular endothelial growth factor binding protein abicipar pegol (abicipar) versus ranibizumab for neovascular age-related macular degeneration. METHODS: Phase 2, multicenter, randomized, double-masked comparison (REACH study, stage 3). Patients (n = 64) received intravitreal injections of abicipar 1 mg or 2 mg at baseline, week 4, and week 8 (3 injections) or ranibizumab 0.5 mg at baseline and monthly (5 injections). RESULTS: In the abicipar 1 mg (n = 25), abicipar 2 mg (n = 23), and ranibizumab (n = 16) arms, respectively, least-squares mean best-corrected visual acuity (BCVA) change from baseline was +6.2, +8.3, and +5.6 letters at week 16 (primary endpoint) and +8.2, +10.0, and +5.3 letters at week 20. Least-squares mean central retinal thickness (CRT) reduction from baseline was 134, 113, and 131 μm at week 16 and 116, 103, and 138 μm at week 20. Intraocular inflammation adverse events (AEs), reported in 5/48 (10.4%) abicipar-treated patients, resolved without sustained vision loss or other sequelae. CONCLUSIONS: Abicipar demonstrated durability of effect: BCVA and CRT improvements were similar between abicipar and ranibizumab at weeks 16 and 20 (8 and 12 weeks after the last abicipar injection and 4 weeks after the last ranibizumab injection). No serious AEs were reported.Item Impact of Modifying Abicipar Manufacturing Process in Patients with Neovascular Age-Related Macular Degeneration: MAPLE Study Results(Dove Press, 2023-05-11) Callanan, David; Khurana, Rahul N.; Maturi, Raj K.; Patel, Sunil; Wykoff, Charles C.; Eichenbaum, David; Khanani, Arshad M.; Hassan, Tarek; Badger, Hanh; Mehta, Shraddha; Le, Grace; Attar, Mayssa; Seal, Jennifer; Li, Xiao-Yan; Ophthalmology, School of MedicinePurpose: To evaluate the impact of modifying the abicipar pegol (abicipar) manufacturing process on the safety and treatment effect of abicipar in patients with neovascular age-related macular degeneration (nAMD). Methods: A new process for manufacturing abicipar was developed to reduce host cell impurities. In a prospective, Phase 2, multicenter, open-label, 28-week clinical trial, patients (n=123) with active nAMD received intravitreal injections of abicipar 2 mg at baseline (day 1) and weeks 4, 8, 16, and 24. Outcome measures included proportion of patients with stable vision (<15-letter loss from baseline; primary endpoint), change from baseline in best-corrected visual acuity (BCVA) and central retinal thickness (CRT), and adverse events. Results: Overall, 8.9% (11/123) of patients experienced intraocular inflammation (IOI) and discontinued treatment. IOI cases were assessed as mild (2.4% [3/123]), moderate (4.9% [6/123]), or severe (1.6% [2/123]) and resolved with steroid treatment. Visual acuity in most patients with IOI (8 of 11) recovered to baseline BCVA or better by study end. No cases of endophthalmitis or retinal vasculitis were reported. Stable vision was maintained for ≥95.9% (≥118/123) of patients at all study visits. At week 28, treatment-naïve patients showed a greater mean improvement from baseline in BCVA compared with previously treated patients (4.4 vs 1.8 letters) and a larger mean CRT reduction from baseline (98.5 vs 45.5 μm). Conclusion: Abicipar produced using a modified manufacturing process showed a moderately lower incidence and severity of IOI compared with Phase 3 abicipar studies. Beneficial effects of treatment were demonstrated.Item Improving the Transduction of Bone Marrow-Derived Cells with an Integrase-Defective Lentiviral Vector(Mary Ann Liebert, Inc., 2018-02) Pay, S. Louise; Qi, Xiaoping; Willard, Jeffrey F.; Godoy, Juliana; Sankhavaram, Kavya; Horton, Ranier; Mitter, Sayak K.; Quigley, Judith L.; Chang, Lung-Ji; Grant, Maria B.; Boulton, Michael E.; Medical and Molecular Genetics, School of MedicineIn lentiviral vector (LV) applications where transient transgene expression is sufficient, integrase-defective lentiviral vectors (IDLVs) are beneficial for reducing the potential for off-target effects associated with insertional mutagenesis. It was previously demonstrated that human RPE65 mRNA expression from an integrating lentiviral vector (ILV) induces endogenous Rpe65 and Cralbp mRNA expression in murine bone marrow-derived cells (BMDCs), initiating programming of the cells to retinal pigment epithelium (RPE)-like cells. These cells regenerate RPE in retinal degeneration models when injected systemically. As transient expression of RPE65 is sufficient to activate endogenous RPE-associated genes for programming BMDCs, use of an ILV is an unnecessary risk. In this study, an IDLV expressing RPE65 (IDLV3-RPE65) was generated. Transduction with IDLV3-RPE65 is less efficient than the integrating vector (ILV3-RPE65). Therefore, IDLV3-RPE65 transduction was enhanced with a combination of preloading 20 × -concentrated viral supernatant on RetroNectin at a multiplicity of infection of 50 and transduction of BMDCs by low-speed centrifugation. RPE65 mRNA levels increased from ∼12-fold to ∼25-fold (p < 0.05) after modification of the IDLV3-RPE65 transduction protocol, achieving expression similar to the ∼27-fold (p < 0.05) increase observed with ILV3-RPE65. Additionally, the study shows that the same preparation of RetroNectin can be used to coat up to three wells with no reduction in transduction. Critically, IDLV3-RPE65 transduction initiates endogenous Rpe65 mRNA expression in murine BMDCs and Cralbp/CRALBP mRNA in both murine and human BMDCs, similar to expression observed in ILV3-RPE65-transduced cells. Systemic administration of ILV3-RPE65 or IDLV3-RPE65 programmed BMDCs in a mouse model of retinal degeneration is sufficient to retain visual function and reduce retinal degeneration compared to mice receiving no treatment or naïve BMDC. It is concluded that IDLV3-RPE65 is appropriate for programming BMDCs to RPE-like cells.Item Molecular Genetic Mechanisms in Age-Related Macular Degeneration(MDPI, 2022-07-12) Shughoury, Aumer; Sevgi, Duriye Damla; Ciulla, Thomas A.; Ophthalmology, School of MedicineAge-related macular degeneration (AMD) is among the leading causes of irreversible blindness worldwide. In addition to environmental risk factors, such as tobacco use and diet, genetic background has long been established as a major risk factor for the development of AMD. However, our ability to predict disease risk and personalize treatment remains limited by our nascent understanding of the molecular mechanisms underlying AMD pathogenesis. Research into the molecular genetics of AMD over the past two decades has uncovered 52 independent gene variants and 34 independent loci that are implicated in the development of AMD, accounting for over half of the genetic risk. This research has helped delineate at least five major pathways that may be disrupted in the pathogenesis of AMD: the complement system, extracellular matrix remodeling, lipid metabolism, angiogenesis, and oxidative stress response. This review surveys our current understanding of each of these disease mechanisms, in turn, along with their associated pathogenic gene variants. Continued research into the molecular genetics of AMD holds great promise for the development of precision-targeted, personalized therapies that bring us closer to a cure for this debilitating disease.Item Restoring retinal polyunsaturated fatty acid balance and retina function by targeting ceramide in AdipoR1-deficient mice(Elsevier, 2024) Lewandowski, Dominik; Gao, Fangyuan; Imanishi, Sanae; Tworak, Aleksander; Bassetto, Marco; Dong, Zhiqian; Pinto, Antonio F. M.; Tabaka, Marcin; Kiser, Philip D.; Imanishi, Yoshikazu; Skowronska-Krawczyk, Dorota; Palczewski, Krzysztof; Ophthalmology, School of MedicineMutations in the adiponectin receptor 1 gene (AdipoR1) lead to retinitis pigmentosa and are associated with age-related macular degeneration. This study explores the effects of AdipoR1 gene deficiency in mice, revealing a striking decline in ω3 polyunsaturated fatty acids (PUFA), an increase in ω6 fatty acids, and elevated ceramides in the retina. The AdipoR1 deficiency impairs peroxisome proliferator-activated receptor α signaling, which is crucial for FA metabolism, particularly affecting proteins associated with FA transport and oxidation in the retina and retinal pigmented epithelium. Our lipidomic and proteomic analyses indicate changes that could affect membrane composition and viscosity through altered ω3 PUFA transport and synthesis, suggesting a potential influence of AdipoR1 on these properties. Furthermore, we noted a reduction in the Bardet-Biedl syndrome proteins, which are crucial for forming and maintaining photoreceptor outer segments that are PUFA-enriched ciliary structures. Diminution in Bardet-Biedl syndrome-proteins content combined with our electron microscopic observations raises the possibility that AdipoR1 deficiency might impair ciliary function. Treatment with inhibitors of ceramide synthesis led to substantial elevation of ω3 LC-PUFAs, alleviating photoreceptor degeneration and improving retinal function. These results serve as the proof of concept for a ceramide-targeted strategy to treat retinopathies linked to PUFA deficiency, including age-related macular degeneration.Item Systemic Injection of RPE65-Programmed Bone Marrow-Derived Cells Prevents Progression of Chronic Retinal Degeneration(Elsevier, 2017-04-05) Qi, Xiaoping; Pay, S. Louise; Yan, Yuanqing; Thomas, James, Jr.; Lewin, Alfred S.; Chang, Lung-Ji; Grant, Maria B.; Boulton, Michael E.; Ophthalmology, School of MedicineBone marrow stem and progenitor cells can differentiate into a range of non-hematopoietic cell types, including retinal pigment epithelium (RPE)-like cells. In this study, we programmed bone marrow-derived cells (BMDCs) ex vivo by inserting a stable RPE65 transgene using a lentiviral vector. We tested the efficacy of systemically administered RPE65-programmed BMDCs to prevent visual loss in the superoxide dismutase 2 knockdown (Sod2 KD) mouse model of age-related macular degeneration. Here, we present evidence that these RPE65-programmed BMDCs are recruited to the subretinal space, where they repopulate the RPE layer, preserve the photoreceptor layer, retain the thickness of the neural retina, reduce lipofuscin granule formation, and suppress microgliosis. Importantly, electroretinography and optokinetic response tests confirmed that visual function was significantly improved. Mice treated with non-modified BMDCs or BMDCs pre-programmed with LacZ did not exhibit significant improvement in visual deficit. RPE65-BMDC administration was most effective in early disease, when visual function and retinal morphology returned to near normal, and less effective in late-stage disease. This experimental paradigm offers a minimally invasive cellular therapy that can be given systemically overcoming the need for invasive ocular surgery and offering the potential to arrest progression in early AMD and other RPE-based diseases.Item β-secretase 1 overexpression by AAV-mediated gene delivery prevents retina degeneration in a mouse model of age-related macular degeneration(Elsevier, 2023) Qi, Xiaoping; Francelin, Carolina; Mitter, Sayak; Boye, Sanford L.; Gu, Hongmei; Quigley, Judith; Grant, Maria B.; Boulton, Michael E.; Ophthalmology, School of MedicineWe reported previously that β-site amyloid precursor protein cleaving enzyme (BACE1) is strongly expressed in the normal retina and that BACE1−/− mice develop pathological phenotypes associated with age-related macular degeneration (AMD). BACE1 expression is increased within the neural retina and retinal pigment epithelium (RPE) in AMD donor eyes suggesting that increased BACE1 is compensatory. We observed that AAV-mediated BACE1 overexpression in the RPE was maintained up to 6 months after AAV1-BACE1 administration. No significant changes in normal mouse visual function or retinal morphology were observed with low-dose vector while the high-dose vector demonstrated some early pathology which regressed with time. No increase in β-amyloid was observed. BACE1 overexpression in the RPE of the superoxide dismutase 2 knockdown (SOD2 KD) mouse, which exhibits an AMD-like phenotype, prevented loss of retinal function and retinal pathology, and this was sustained out to 6 months. Furthermore, BACE1 overexpression was able to inhibit oxidative stress, microglial changes, and loss of RPE tight junction integrity (all features of AMD) in SOD2 KD mice. In conclusion, BACE1 plays a key role in retina/RPE homeostasis, and BACE1 overexpression offers a novel therapeutic target in the treatment of AMD.