Efficient mitochondrial biogenesis drives incomplete penetrance in Leber's hereditary optic neuropathy

Leber's hereditary optic neuropathy is a maternally inherited blinding disease caused as a result of homoplasmic point mutations in complex I subunit genes of mitochondrial DNA. It is characterized by incomplete penetrance, as only some mutation carriers become affected. Thus, the mitochondrial DNA mutation is necessary but not sufficient to cause optic neuropathy. Environmental triggers and genetic modifying factors have been considered to explain its variable penetrance. We measured the mitochondrial DNA copy number and mitochondrial mass indicators in blood cells from affected and carrier individuals, screening three large pedigrees and 39 independently collected smaller families with Leber's hereditary optic neuropathy, as well as muscle biopsies and cells isolated by laser capturing from post-mortem specimens of retina and optic nerves, the latter being the disease targets. We show that unaffected mutation carriers have a significantly higher mitochondrial DNA copy number and mitochondrial mass compared with their affected relatives and control individuals. Comparative studies of fibroblasts from affected, carriers and controls, under different paradigms of metabolic demand, show that carriers display the highest capacity for activating mitochondrial biogenesis. Therefore we postulate that the increased mitochondrial biogenesis in carriers may overcome some of the pathogenic effect of mitochondrial DNA mutations. Screening of a few selected genetic variants in candidate genes involved in mitochondrial biogenesis failed to reveal any significant association. Our study provides a valuable mechanism to explain variability of penetrance in Leber's hereditary optic neuropathy and clues for high throughput genetic screening to identify the nuclear modifying gene(s), opening an avenue to develop predictive genetic tests on disease risk and therapeutic strategies.TelethonAssociazione Serena Talarico per i giovani nel mondo and Fondazione Giuseppe Tomasello O.N.L.U.S.Mitocon OnlusResearch to Prevent BlindnessInternational Foundation for Optic Nerve Diseases (IFOND)Struggling Within Leber'sPoincenot FamilyEierman FoundationNational Eye InstituteUniv Rome, Dept Radiol Oncol & Pathol, Rome, ItalyUniv Bologna, Dept Biomed & NeuroMotor Sci DIBINEM, Bologna, ItalyUniv Bari, Dept Biosci Biotechnol & Biopharmaceut, Bari, ItalyBellaria Hosp, IRCCS Ist Sci Neurol Bologna, I-40139 Bologna, ItalyUSC, Keck Sch Med, Dept Ophthalmol, Los Angeles, CA USAUSC, Keck Sch Med, Dept Neurosurg, Los Angeles, CA USAUniv Trieste, Dept Reprod Sci Dev & Publ Hlth, Trieste, ItalyUniv Trieste, IRCCS Burlo Garofolo Children Hosp, Trieste, ItalyNewcastle Univ, Inst Med Genet, Newcastle Upon Tyne NE1 7RU, Tyne & Wear, EnglandFdn Ist Neurol Carlo Besta IRCCS, Unit Mol Neurogenet, Milan, ItalyMRC Mitochondrial Biol Unit, Cambridge, EnglandFed Univ São Paulo UNIFESP, Dept Ophthalmol, São Paulo, BrazilUniv São Paulo, Inst Psychol, Dept Expt Psychol, São Paulo, BrazilStudio Oculist dAzeglio, Bologna, ItalyOsped San Giovanni Evangelista, Tivoli, ItalyAzienda Osped San Camillo Forlanini, Rome, ItalyUniv Rome, Dipartimento Metodi & Modelli Econ Finanza & Terr, Rome, ItalyUniv Rome, Dept Mol Med, Rome, ItalyFed Univ São Paulo UNIFESP, Dept Ophthalmol, São Paulo, BrazilTelethon: GGP06233Telethon: GGP11182Telethon: GPP10005National Eye Institute: EY03040Web of Scienc

Relationship between nerve fiber layer hemorrhages and outcomes in central retinal vein occlusion

PURPOSE. To evaluate the depth and pattern of retinal hemorrhage in acute central retinal vein occlusion (CRVO) and to correlate these with visual and anatomic outcomes. METHODS. Retinal hemorrhages were evaluated with color fundus photography and fluorescein angiography at baseline and follow-up. Snellen visual acuity (VA), central foveal thickness (CFT), extent of retinal ischemia, and development of neovascularization were analyzed. RESULTS. 108 eyes from 108 patients were evaluated. Mean age was 63.6 ± 16.1 years with a predilection for the right eye (73.1). Average follow-up was 17.2 ± 19.2 months. Mean VA at baseline was 20/126 and 20/80 at final follow-up. Baseline (P = 0.005) and final VA (P = 0.02) in eyes with perivascular nerve fiber layer (NFL) hemorrhages were significantly worse than in eyes with deep hemorrhages alone. Baseline CFT was greater in the group with perivascular hemorrhages (826 ± 394 μm) compared to the group with deep hemorrhages alone (455 ± 273 μm, P < 0.001). The 10 disc areas of retinal ischemia was more common in patients with perivascular (80.0) and peripapillary (31.3) versus deep hemorrhages alone (16.1, P < 0.001). Neovascularization of the iris was more common, although this differrence was not significant, in the groups with peripapillary (14.3) and perivascular (2.0) NFL versus deep hemorrhages alone (0.0). CONCLUSIONS. NFL retinal hemorrhages at baseline correlate with more severe forms of CRVO, with greater macular edema, poorer visual outcomes, and greater risk of ischemia and neovascularization. This may be related to the organization of the retinal capillary plexus. The depth and pattern of distribution of retinal hemorrhages in CRVO may provide an easily identifiable early biomarker of CRVO prognosis. Copyright 2020 The Author

THE SPECTRUM OF AMALRIC TRIANGULAR CHOROIDAL INFARCTION.

To describe the multimodal imaging findings, including optical coherence tomography angiography analysis, and spectrum of etiologies associated with Amalric triangular choroidal infarction. This study is a multicenter, retrospective, observational case series review of the clinical and multimodal imaging findings for six patients with Amalric triangular choroidal infarction. Six patients (10 eyes) with Amalric triangular choroidal infarction were enrolled. Patients' ages ranged from 7 years to 90 years (mean 54 years, median 60 years). Wedge-shaped or triangular areas of choroidal ischemia were evident with fluorescein angiography in all patients and with indocyanine green angiography in one patient. Optical coherence tomography angiography demonstrated choriocapillaris flow reduction that colocalized with outer retinal structural abnormalities with en face optical coherence tomography and corresponded with the triangular zones of choroidal infarction identified with fluorescein angiography in one patient. Etiologies included giant cell arteritis in three cases: traumatic carotid dissection, traumatic retrobulbar hemorrhage, and malignant hypertension secondary to lupus-associated nephropathy. The Amalric triangular syndrome of choroidal infarction can occur as a result of a spectrum of etiologies, especially giant cell arteritis. Infarction is evident on traditional angiography in all cases. Optical coherence tomography angiography may provide a simple noninvasive tool to evaluate choroidal ischemia

Long-term visual and anatomic outcomes of patients with peripapillary pachychoroid syndrome.

BACKGROUND/AIMS: To analyse the long-term anatomic and visual outcomes of patients with peripapillary pachychoroid syndrome (PPS), a recently described entity in the pachychoroid disease spectrum. METHODS: This study retrospectively included patients from several retina centres worldwide. Visual acuity (VA), retinal thickness and choroidal thickness at baseline, 6 months and final follow-up were assessed. Temporal trends in VA and anatomic characteristics were evaluated. Visual and anatomic outcomes in eyes that were observed versus those that were treated were analysed. RESULTS: Fifty-six eyes of 35 patients were included with mean follow-up of 27±17 months. Median VA was 20/36 at baseline and remained stable through follow-up (p=0.77). Retinal thickness significantly decreased subfoveally (p=0.012), 1.5 mm nasal to the fovea (p=0.002) and 3.0 mm nasal to the fovea (p=0.0035) corresponding to areas of increased thickening at baseline. Choroidal thickness significantly decreased subfoveally (p=0.0030) and 1.5 mm nasal to the fovea (p=0.0030). Forty-three eyes were treated with modalities including antivascular endothelial growth factor injection, photodynamic therapy, and others. VA remained stable in treated eyes over follow-up (p=0.67). An isolated peripapillary fluid pocket in the outer nuclear layer was characteristic of PPS. CONCLUSION: Patients with PPS experienced decreased retinal oedema and decreased choroidal thickening throughout the course of disease. While some patients experienced visual decline, the overall visual outcome was relatively favourable and independent of trends in retinal or choroidal thickening

PERIPAPILLARY PACHYCHOROID SYNDROME

Purpose: To describe the features of peripapillary pachychoroid syndrome (PPS), a novel pachychoroid disease spectrum (PDS) entity. Methods: Medical records of 31 eyes (16 patients) with choroidal thickening associated with intraretinal and/or subretinal fluid in the nasal macula extending from the disk were reviewed (patients with PPS). Choroidal thickness was compared with 2 age-matched cohorts: typical PDS (17 eyes with central serous chorioretinopathy or pachychoroid neovasculopathy) and 19 normal eyes. Results: The patients with PPS were 81% men aged 71 ± 7 years. Peripapillary pachychoroid syndrome eyes displayed thicker nasal versus temporal macular choroids, unlike PDS eyes with thicker temporal macular choroids (P < 0.0001). Peripapillary intraretinal and/or subretinal fluid was often overlying dilated Haller layer vessels (pachyvessels). Fundus autofluorescence and fluorescein angiography illustrated peripapillary pigmentary mottling without focal leakage. Most PPS eyes (70%) exhibited other PDS findings including serous pigment epithelial detachment or gravitational tracks. Indocyanine green angiography illustrated dilated peripapillary pachyvessels and choroidal hyperpermeability. The disk was usually crowded, with edema noted in 4/31 (13%) eyes and mild late fluorescein disk leakage identified in half of the cases. Choroidal folds (77%), short axial lengths (39% less than 23 mm), and hyperopia (86%) were common. Conclusion: Peripapillary pachychoroid syndrome is a distinct PDS variant, in which peripapillary choroidal thickening is associated with nasal macular intraretinal and/or subretinal fluid and occasional disk edema. Recognition of PPS is important to distinguish it from disorders with overlapping features such as posterior uveitis and neuro-ophthalmologic conditions

The outcome of fluocinolone acetonide intravitreal implant is predicted by the response to dexamethasone implant in diabetic macular oedema

Background/Objectives: To investigate if the visual and anatomic response to the first dexamethasone implant (DEX) predicts the 12-month clinical outcome after shifting to fluocinolone acetonide (FAc) implant in patients with diabetic macular oedema (DMO). Methods: Retrospective cohort study including pseudophakic patients with previously treated DMO, undergone one or more DEX injections before FAc. Functional and morphologic response to DEX was defined based on the best-corrected visual acuity (BCVA) and central macular thickness (CMT) changes after the first DEX, respectively. Steroid-response was defined as intraocular pressure (IOP) elevation ≥5 mmHg or IOP > 21 mmHg after any previous DEX exposure. Pairwise comparisons for BCVA, CMT, and IOP after FAc were performed with linear mixed models and a repeated-measure design. Results: Forty-four eyes of 33 patients were included. Patients were shifted to FAc after a mean ± standard deviation of 4.6 ± 3.2 DEX injections. Overall, BCVA and CMT improved during the first 12 months after switching to FAc (p = 0.04 and p < 0.001, respectively). Only eyes with a good morphologic response to DEX had a significant CMT reduction after FAc (p < 0.001), while no significant relationship was found between BCVA improvement after DEX and after FAc. IOP elevation occurred in 9 eyes (20%) following DEX implant. These eyes carried a 20-fold increased risk of having an IOP rise after FAc (p < 0.001), with a non-linear relationship between the IOP increase after DEX and the one after FAc. Conclusion: The response to previous DEX may anticipate the morphologic response to subsequent FAc. Eyes with steroid-induced IOP elevation after DEX are at a high risk of IOP increase after FAc. The visual response after FAc was not associated with the visual response to previous steroids, indicating that FAc may have a role also in patients refractory to DEX implant