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Kang J, Cho SS, Kim HY, Lee BH, Cho HJ, Gwak YS. Regional Hyperexcitability and Chronic Neuropathic Pain Following Spinal Cord Injury. Cell Mol Neurobiol 2020;40(6):861-878.Abstract
Spinal cord injury (SCI) causes maladaptive changes to nociceptive synaptic circuits within the injured spinal cord. Changes also occur at remote regions including the brain stem, limbic system, cortex, and dorsal root ganglia. These maladaptive nociceptive synaptic circuits frequently cause neuronal hyperexcitability in the entire nervous system and enhance nociceptive transmission, resulting in chronic central neuropathic pain following SCI. The underlying mechanism of chronic neuropathic pain depends on the neuroanatomical structures and electrochemical communication between pre- and postsynaptic neuronal membranes, and propagation of synaptic transmission in the ascending pain pathways. In the nervous system, neurons are the only cell type that transmits nociceptive signals from peripheral receptors to supraspinal systems due to their neuroanatomical and electrophysiological properties. However, the entire range of nociceptive signaling is not mediated by any single neuron. Current literature describes regional studies of electrophysiological or neurochemical mechanisms for enhanced nociceptive transmission post-SCI, but few studies report the electrophysiological, neurochemical, and neuroanatomical changes across the entire nervous system following a regional SCI. We, along with others, have continuously described the enhanced nociceptive transmission in the spinal dorsal horn, brain stem, thalamus, and cortex in SCI-induced chronic central neuropathic pain condition, respectively. Thus, this review summarizes the current understanding of SCI-induced neuronal hyperexcitability and maladaptive nociceptive transmission in the entire nervous system that contributes to chronic central neuropathic pain.
Levy JM, Yeh W-H, Pendse N, Davis JR, Hennessey E, Butcher R, Koblan LW, Comander J, Liu Q, Liu DR. Cytosine and adenine base editing of the brain, liver, retina, heart and skeletal muscle of mice via adeno-associated viruses. Nat Biomed Eng 2020;4(1):97-110.Abstract
The success of base editors for the study and treatment of genetic diseases depends on the ability to deliver them in vivo to the relevant cell types. Delivery via adeno-associated viruses (AAVs) is limited by AAV packaging capacity, which precludes the use of full-length base editors. Here, we report the application of dual AAVs for the delivery of split cytosine and adenine base editors that are then reconstituted by trans-splicing inteins. Optimized dual AAVs enable in vivo base editing at therapeutically relevant efficiencies and dosages in the mouse brain (up to 59% of unsorted cortical tissue), liver (38%), retina (38%), heart (20%) and skeletal muscle (9%). We also show that base editing corrects, in mouse brain tissue, a mutation that causes Niemann-Pick disease type C (a neurodegenerative ataxia), slowing down neurodegeneration and increasing lifespan. The optimized delivery vectors should facilitate the efficient introduction of targeted point mutations into multiple tissues of therapeutic interest.
Riau AK, Lwin NC, Gelfand L, Hu H, Liedberg B, Chodosh J, Venkatraman SS, Mehta JS. Surface modification of corneal prosthesis with nano-hydroxyapatite to enhance in vivo biointegration. Acta Biomater 2020;107:299-312.Abstract
The majority of clinical corneal prostheses (KPros) adopt a core-skirt configuration. This configuration is favored owing to the optic core (generally a cylindrical, acrylic-based material, such as PMMA), that not only provides a clear window for the patients' vision, but also confers resistance to biodegradability. The surrounding skirt (typically a biological material, such as corneal tissue) allows for host tissue integration. However, due to poor biointegration between the dissimilar core and skirt materials, it results in a weak adhesion at the interface, giving rise to clinical complications, such as bacterial infections in the tissue-PMMA interface and device extrusion. Here, we physically immobilized nano-hydroxyapatite (nHAp) on a PMMA cylinder via a dip-coating technique, to create a bioactive surface that improved biointegration in vivo. We established that the nHAp coating was safe and stable in the rabbit cornea over five weeks. More importantly, we found that apoptotic, wound healing and inflammatory responses to nHAp-coated PMMA were substantially milder than to non-coated PMMA. More mature collagen, similar to the non-operated cornea, was maintained in the corneal stroma adjacent to the nHAp-coated implant edge. However, around the non-coated cylinder, an abundant new and loose connective tissue formed, similar to bone tissue response to bioinert scaffolds. As a result of superior biointegration, tissue adhesion with nHAp-coated PMMA cylinders was also significantly enhanced compared to non-coated cylinders. This study set a precedent for the future application of the nHAp coating on clinical KPros. STATEMENT OF SIGNIFICANCE: Currently, all clinical corneal prostheses utilize as-manufactured, non-surface modified PMMA optic cylinder. The bioinert cylinder, however, has poor biointegration and adhesion with the surrounding biological tissue, which can give rise to postoperative complications, such as microbial invasion in the tissue-PMMA loose interface and PMMA optic cylinder extrusion. In the current study, we showed that surface modification of the PMMA cylinder with bioactive nano-hydroxyapatite (nHAp) significantly enhanced its biointegration with corneal stromal tissue in vivo. The superior biointegration of the nHAp-coated PMMA was signified by a more attenuated corneal wound healing, inflammatory and fibrotic response, and better tissue apposition, as well as a significantly improved corneal stromal tissue adhesion when compared to the non-coated PMMA.
McKay MK, Borkar DS, Sevgi DD, Susarla G, Papaliodis GN, Sobrin L. Comparison of Modified Posterior Sub-Tenon's vs. Trans-Septal Triamcinolone Injection for Non-infectious Uveitis. Ocul Immunol Inflamm 2020;:1-8.Abstract
: To compare the safety and efficacy of trans-septal vs. modified posterior sub-Tenon's (PST) corticosteroid injections for noninfectious uveitis.: Retrospective comparison of periocular triamcinolone injection by modified PST (n = 36) vs. traditional trans-septal (n = 79) techniques. Safety and efficacy outcomes were analyzed with regression models.: There was no significant difference in visual acuity improvement between the groups at 6 months. There were higher rates of vitritis resolution in the modified PST group but this was not statistically significant (85.7% vs 62.9%, = .07). Intraocular pressure (IOP) elevation rate trended higher with the modified PST injection (21.9% vs 9.0%, = .06), with no instances of glaucoma surgery in either group. Two modified PST injection patients with refractory IOP rises had IOP normalization after corticosteroid depot removal. One year cataract surgery rates were similar.: Modified PST injection offers clinical efficacy but with possibly higher IOP response rate which could be managed with corticosteroid removal.
Pflugfelder SC, Massaro-Giordano M, Perez VL, Hamrah P, Deng SX, Espandar L, Foster SC, Affeldt J, Seedor JA, Afshari NA, Chao W, Allegretti M, Mantelli F, Dana R. Topical Recombinant Human Nerve Growth Factor (Cenegermin) for Neurotrophic Keratopathy: A Multicenter Randomized Vehicle-Controlled Pivotal Trial. Ophthalmology 2020;127(1):14-26.Abstract
PURPOSE: To evaluate the efficacy and safety of topical cenegermin (recombinant human nerve growth factor) in patients with neurotrophic keratopathy. DESIGN: Multicenter, randomized, double-masked, vehicle-controlled trial. PARTICIPANTS: Patients with neurotrophic persistent epithelial defect with or without stromal thinning. METHODS: The NGF0214 trial, conducted among 11 sites in the United States, randomized 48 patients 1:1 to cenegermin 20 μg/ml or vehicle eye drops, 6 drops daily for 8 weeks of masked treatment. Follow-up was 24 weeks. Safety was assessed in all patients who received study drug. Efficacy was assessed by intention to treat. MAIN OUTCOME MEASURES: The primary end point was healing of the neurotrophic lesion (persistent epithelial defect or corneal ulcer) after 8 weeks of masked treatment. Masked central readers measured neurotrophic lesions in randomized clinical pictures, then assessed healing status conventionally (<0.5 mm of fluorescein staining in the greatest dimension of the lesion area) and conservatively (0-mm lesion staining and no other residual staining). Secondary variables included corneal healing at 4 weeks of masked treatment (key secondary end point), overall changes in lesion size, rates of disease progression, and changes in visual acuity and corneal sensitivity from baseline to week 8. RESULTS: Conventional assessment of corneal healing showed statistically significant differences at week 8: compared to 7 of 24 vehicle-treated patients (29.2%), 16 of 23 cenegermin-treated patients (69.6%) achieved less than 0.5 mm of lesion staining (+40.4%; 95% confidence interval [CI], 14.2%-66.6%; P = 0.006). Conservative assessment of corneal healing also reached statistical significance at week 8: compared to 4 of 24 vehicle-treated patients (16.7%), 15 of 23 cenegermin-treated patients (65.2%) achieved 0 mm of lesion staining and no other residual staining (+48.6%; 95% CI, 24.0%-73.1%; P < 0.001). Moreover, the conservative measure of corneal healing showed statistical significance at week 4 (key secondary end point). Compared to vehicle, cenegermin-treated patients showed statistically significant reductions in lesion size and disease progression rates during masked treatment. Cenegermin was well tolerated; adverse effects were mostly local, mild, and transient. CONCLUSIONS: Cenegermin treatment showed higher rates of corneal healing than vehicle in neurotrophic keratopathy associated with nonhealing corneal defects.
Fay A, Nallasamy N, Allen RC, Bernardini FP, Bilyk JR, Cockerham K, Cruz AA, Devoto M, Dolman PJ, Dutton JJ, Jordan DR, Kersten R, Kim Y-D, Lucarelli MJ, McNab AA, Mombaerts I, Mourits M, Nerad J, Perry JD, Rose G, Saeed P, Seah LL, Selva D, Sivak-Callcott J, Strianese D, Verity DH, Verity DH. Perioperative Prophylactic Antibiotics in 1,250 Orbital Surgeries. Ophthalmic Plast Reconstr Surg 2020;36(4):385-389.Abstract
PURPOSE: Intravenous antibiotic prophylaxis is used for many clean-contaminated surgeries or clean surgeries with an implant, but its value for clean orbital surgery has not been determined. This study investigated infection risks and adverse effects related to antibiotics in patients undergoing orbital surgery. METHODS: A prospective, nonrandomized comparative case series of all patients undergoing orbital surgery with participating surgeons between October 1, 2013, and March 1, 2015. Types of surgery, antibiotic regimens, corticosteroid use, antibiotic side effects, and surgical site infections (SSIs) were entered into an electronic database and subsequently analyzed. Cases in which patients received postoperative oral antibiotics were analyzed separately. RESULTS: Of 1,250 consecutive orbital surgeries, 1,225 met inclusion criteria. A total of 1208 patients were included in the primary analysis: 603 received no antibiotic prophylaxis (group A), and 605 received a single dose of intravenous antibiotic (group B). Five patients (0.42%) developed an SSI, 3 in group A and 2 in group B. The difference in SSI rates was not statistically significant between the 2 groups (p = 0.66). Antibiotic prophylaxis, alloplastic implants, paranasal sinus entry, and corticosteroid use were not associated with differences in SSI rates. All SSIs resolved on a single course of oral antibiotics; an implant was removed in 1 case. There were no complications associated with a single dose of intravenous prophylaxis. However, 12% of 17 patients (group C) who received 1 week of oral postoperative prophylactic antibiotics developed antibiotic-related complications (diarrhea, renal injury), yielding a number needed to harm of 8.5. CONCLUSIONS: In this large series, antibiotic prophylaxis does not appear to have reduced the already low incidence of SSI following orbital surgery. Given the detriments of systemic antibiotics, the rarity of infections related to orbital surgery, and the efficacy of treating such infections should they occur, patients undergoing orbital surgery should be educated to the early symptoms of postoperative infection and followed closely, but do not routinely require perioperative antibiotics.
Wu W, Zhou G, Han H, Huang X, Jiang H, Mukai S, Kazlauskas A, Cui J, Matsubara JA, Vanhaesebroeck B, Xia X, Wang J, Lei H. PI3Kδ as a Novel Therapeutic Target in Pathological Angiogenesis. Diabetes 2020;69(4):736-748.Abstract
Diabetic retinopathy is the most common microvascular complication of diabetes, and in the advanced diabetic retinopathy appear vitreal fibrovascular membranes that consist of a variety of cells, including vascular endothelial cells (ECs). New therapeutic approaches for this diabetic complication are urgently needed. Here, we report that in cultured human retinal microvascular ECs, high glucose induced expression of p110δ, which was also expressed in ECs of fibrovascular membranes from patients with diabetes. This catalytic subunit of a receptor-regulated PI3K isoform δ is known to be highly enriched in leukocytes. Using genetic and pharmacological approaches, we show that p110δ activity in cultured ECs controls Akt activation, cell proliferation, migration, and tube formation induced by vascular endothelial growth factor, basic fibroblast growth factor, and epidermal growth factor. Using a mouse model of oxygen-induced retinopathy, p110δ inactivation was found to attenuate pathological retinal angiogenesis. p110δ inhibitors have been approved for use in human B-cell malignancies. Our data suggest that antagonizing p110δ constitutes a previously unappreciated therapeutic opportunity for diabetic retinopathy.
Craig JE, Han X, Qassim A, Hassall M, Cooke Bailey JN, Kinzy TG, Khawaja AP, An J, Marshall H, Gharahkhani P, Igo RP, Graham SL, Healey PR, Ong J-S, Zhou T, Siggs O, Law MH, Souzeau E, Ridge B, Hysi PG, Burdon KP, Mills RA, Landers J, Ruddle JB, Agar A, Galanopoulos A, White AJR, Willoughby CE, Andrew NH, Best S, Vincent AL, Goldberg I, Radford-Smith G, Martin NG, Montgomery GW, Vitart V, Hoehn R, Wojciechowski R, Jonas JB, Aung T, Pasquale LR, Cree AJ, Sivaprasad S, Vallabh NA, Vallabh NA, and Consortium UKBEV, Viswanathan AC, Pasutto F, Haines JL, Klaver CCW, van Duijn CM, Casson RJ, Foster PJ, Khaw PT, Hammond CJ, Mackey DA, Mitchell P, Lotery AJ, Wiggs JL, Hewitt AW, Macgregor S. Multitrait analysis of glaucoma identifies new risk loci and enables polygenic prediction of disease susceptibility and progression. Nat Genet 2020;52(2):160-166.Abstract
Glaucoma, a disease characterized by progressive optic nerve degeneration, can be prevented through timely diagnosis and treatment. We characterize optic nerve photographs of 67,040 UK Biobank participants and use a multitrait genetic model to identify risk loci for glaucoma. A glaucoma polygenic risk score (PRS) enables effective risk stratification in unselected glaucoma cases and modifies penetrance of the MYOC variant encoding p.Gln368Ter, the most common glaucoma-associated myocilin variant. In the unselected glaucoma population, individuals in the top PRS decile reach an absolute risk for glaucoma 10 years earlier than the bottom decile and are at 15-fold increased risk of developing advanced glaucoma (top 10% versus remaining 90%, odds ratio = 4.20). The PRS predicts glaucoma progression in prospectively monitored, early manifest glaucoma cases (P = 0.004) and surgical intervention in advanced disease (P = 3.6 × 10). This glaucoma PRS will facilitate the development of a personalized approach for earlier treatment of high-risk individuals, with less intensive monitoring and treatment being possible for lower-risk groups.
Mehta MC, Narayanan R, Thomas Aretz H, Khanna R, Rao GN. The L V Prasad Eye Institute: A comprehensive case study of excellent and equitable eye care. Healthc (Amst) 2020;:100408.Abstract
Global healthcare delivery systems are facing ever-increasing challenges on multiple fronts. The need to study and define successful models of care delivery systems has become increasingly important. The L V Prasad Eye Institute (LVPEI) has a distinctive eye care delivery system offering rich lessons at many operational levels. The system has been developed on the basis of LVPEI's foundational public eye health study, and follows a complexity-driven (dependent on disease complexity) clinical care system forming a five-tier pyramidal model - at the apex is the quaternary care centre at Hyderabad, followed by increasing numbers of tertiary, secondary or community, primary, and rural eye care centres, where the revenue from paying patients covers free-care via an economic cross-subsidy. This has achieved a level of scale, efficiency, social impact, and clinical and scientific innovation rarely seen in a single health system. Building on the foundational principles of this pyramidal care with a robust economic cross-subsidy model, LVPEI has seamlessly established successful professional, academic, and educational systems that combine innovation, scientific discovery, and the development of in-house technologies focused on improving service quality and clinical decision making. In this case study, we show that all elements of the LVPEI model are practical and may be applicable to academic medical centres in diverse healthcare settings; currently, this is being tested in Liberia, West Africa.
Xin T, Han H, Wu W, Huang X, Cui J, Matsubara JA, Song J, Wang F, Colyer M, Lei H. Idelalisib inhibits vitreous-induced Akt activation and proliferation of retinal pigment epithelial cells from epiretinal membranes. Exp Eye Res 2020;190:107884.Abstract
Proliferative vitreoretinopathy (PVR) is a blinding fibrotic eye disease that develops in 8-10% of patients who undergo primary retinal detachment-reparative surgery and in 40-60% of patients with open-globe injury. At present, there is no pharmacological treatment for this devastating disease. Vitreal growth factors activate their respective receptors of cells in the vitreous, trigger their downstream signaling transduction (e.g. phosphoinositide 3 kinases (PI3Ks)/Akt), and drive cellular responses intrinsic to the pathogenesis of PVR. PI3Ks play a central role in experimental PVR. However, which isoform(s) are involved in PVR pathogenesis remain unknown. Herein, we show that p110δ, a catalytic subunit of receptor-regulated PI3K isoform δ, is highly expressed in epiretinal membranes from patients with PVR, and that idelalisib, a specific inhibitor of PI3Kδ, effectively inhibits vitreous-induced Akt activation, proliferation, migration and contraction of retinal pigment epithelial cells derived from an epiretinal membrane of a PVR patient. Small molecules of kinase inhibitors have shown great promise as a class of therapeutics for a variety of human diseases. The data herein suggest that idelalisib is a promising PVR prophylactic.
Tan NYQ, Friedman DS, Stalmans I, Ahmed IIK, Sng CCA. Glaucoma screening: where are we and where do we need to go?. Curr Opin Ophthalmol 2020;31(2):91-100.Abstract
PURPOSE OF REVIEW: Current recommendations for glaucoma screening are decidedly neutral. No studies have yet documented improved long-term outcomes for individuals who undergo glaucoma screening versus those who do not. Given the long duration that would be required to detect a benefit, future studies that may answer this question definitively are unlikely. Nevertheless, advances in artificial intelligence and telemedicine will lead to more effective screening at lower cost. With these new technologies, additional research is needed to determine the costs and benefits of screening for glaucoma. RECENT FINDINGS: Using optic disc photographs and/or optical coherence tomography, deep learning systems appear capable of diagnosing glaucoma more accurately than human graders. Eliminating the need for expert graders along with better technologies for remote imaging of the ocular fundus will allow for less expensive screening, which could enable screening of individuals with otherwise limited healthcare access. In India and China, where most glaucoma remains undiagnosed, glaucoma screening was recently found to be cost-effective. SUMMARY: Recent advances in artificial intelligence and telemedicine have the potential to increase the accuracy, reduce the costs, and extend the reach of screening. Further research into implementing these technologies in glaucoma screening is required.
Liu C-H, Huang S, Britton WR, Chen J. MicroRNAs in Vascular Eye Diseases. Int J Mol Sci 2020;21(2)Abstract
Since the discovery of the first microRNA (miRNA) decades ago, studies of miRNA biology have expanded in many biomedical research fields, including eye research. The critical roles of miRNAs in normal development and diseases have made miRNAs useful biomarkers or molecular targets for potential therapeutics. In the eye, ocular neovascularization (NV) is a leading cause of blindness in multiple vascular eye diseases. Current anti-angiogenic therapies, such as anti-vascular endothelial growth factor (VEGF) treatment, have their limitations, indicating the need for investigating new targets. Recent studies established the roles of various miRNAs in the regulation of pathological ocular NV, suggesting miRNAs as both biomarkers and therapeutic targets in vascular eye diseases. This review summarizes the biogenesis of miRNAs, and their functions in the normal development and diseases of the eye, with a focus on clinical and experimental retinopathies in both human and animal models. Discovery of novel targets involving miRNAs in vascular eye diseases will provide insights for developing new treatments to counter ocular NV.
Lambert SR, VanderVeen DK, Kim SJ. Reply. Ophthalmology 2020;127(1):e6-e7.

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