Publications

2015

OBJECTIVES: Novel therapeutics are an important part of ophthalmologists' armamentarium, and the risks and benefits of these therapies must be carefully evaluated. We sought to quantify the characteristics of the pivotal clinical trials supporting the regulatory approval of new ophthalmic drugs and medical devices. DESIGN: Retrospective observational study. SETTING AND DATA SOURCE: Medical review dossiers for new ophthalmic drug and high-risk device approvals released publicly by the US Food and Drug Administration (FDA). MAIN OUTCOME MEASURES: Proportion of pivotal trials with randomisation, masking, active or placebo controls and subgroup analyses; total and median number of trial enrollees; and the number of drugs and devices approved with required postapproval studies. RESULTS: From 2002 to 2012, the FDA approved 11 ophthalmic drugs and 25 devices. The pivotal trials underlying the approvals of ophthalmic drugs in our study cohort enrolled a median of 809 patients. Virtually all drug trials were randomised and masked (91%), of which 7 (70%) used a placebo control. Pivotal trials for ophthalmic devices enrolled 324 patients on average, and significantly fewer trials for ophthalmic devices versus drugs were randomised (16% vs 91%; p<0.001) or masked (12% vs 91%; p<0.001). 8 (32%) ophthalmic devices and 6 (55%) ophthalmic drugs were approved with required postapproval studies. CONCLUSIONS: Ophthalmic therapeutics were approved based on varying levels of evidence. Postapproval studies could be used to confirm or refute early indications of safety and effectiveness of these therapeutics, with the study results accessible to patients and clinicians who need to make informed treatment decisions.

Patel A, Rashid A, Jakobiec F, Lefebvre D, Yoon M. Orbital Branch of the Infraorbital Artery: Further Characterization of an Important Surgical Landmark.. Orbit. 2015;34(4):212–5.

The orbital branch of the infraorbital artery, a key vascular structure that is not universally noted in orbital textbooks and atlases, is clinically significant, since injury to it can result in perioperative hemorrhage. We conducted a cadaver dissection to document its presence, measure its location, and evaluate it histopathologically. It was present in 8 of 9 orbits and was a mean distance of 16.6 mm (range 10-23) from the inferior orbital rim. In half of the specimens, there were 2 separate structures seen. Histopathology confirmed these structures to be neurovascular bundles.

In the study presented by D. S. Kohane and co-workers on page 1159, fluorescein molecules are initially bound to collagen fibers through UV-sensitive bonds. Collagen fibers are exposed to NIR light, which is upconverted to UV light through second harmonic generation. The UV-sensitive bonds absorb the upconverted UV light and undergo an irreversible cleavage releasing the fluorescein molecules.

Silva P, Cavallerano J, Tolson A, Rodriguez J, Rodriguez S, Ajlan R, Tolls D, Patel B, Sehizadeh M, Thakore K, Sun J, Aiello LP. Real-Time Ultrawide Field Image Evaluation of Retinopathy in a Diabetes Telemedicine Program.. Diabetes Care. 2015;38(9):1643–9.

OBJECTIVE: To evaluate the ability of trained nonphysician retinal imagers to perform diabetic retinopathy (DR) evaluation at the time of ultrawide field retinal (UWF) imaging in a teleophthalmology program. RESEARCH DESIGN AND METHODS: Clinic patients with diabetes received Joslin Vision Network protocol retinal imaging as part of their standard medical care. Retinal imagers evaluated UWF images for referable DR at the time of image capture. Training of the imagers included 4 h of standardized didactic lectures and 12 h of guided image review. Real-time evaluations were compared with standard masked gradings performed at a centralized reading center. RESULTS: A total of 3,978 eyes of 1,989 consecutive patients were imaged and evaluated. By reading center evaluation, 3,769 eyes (94.7%) were gradable for DR, 1,376 (36.5%) had DR, and 580 (15.3%) had referable DR. Compared with the reading center, real-time image evaluation had a sensitivity and specificity for identifying more than minimal DR of 0.95 (95% CI 0.94-0.97) and 0.84 (0.82-0.85), respectively, and 0.99 (0.97-1.00) and 0.76 (0.75-0.78), respectively, for detecting referable DR. Only three patients with referable DR were not identified by imager evaluation. CONCLUSIONS: Point-of-care evaluation of UWF images by nonphysician imagers following standardized acquisition and evaluation protocols within an established teleophthalmology program had good sensitivity and specificity for detection of DR and for identification of referable retinal disease. With immediate image evaluation, <0.1% of patients with referable DR would be missed, reading center image grading burden would be reduced by 60%, and patient feedback would be expedited.

Barhoumi A, Salvador-Culla B, Kohane D. NIR-Triggered Drug Delivery by Collagen-Mediated Second Harmonic Generation.. Adv Healthc Mater. 2015;4(8):1159–63.

Second harmonic generation is a process through which nonlinear materials such as collagen can absorb two photons and scatter one with twice the energy. Collagen upconverts 730 nm (near-IR) to 365 nm (UV) through second harmonic generation, which cleaves a molecule bound to collagen via a UV-sensitive linker.

Alpen D, Tran HV, Guex N, Venturini G, Munier F, Schorderet D, Haider N, Escher P. Differential Dimerization of Variants Linked to Enhanced S-Cone Sensitivity Syndrome (ESCS) Located in the NR2E3 Ligand-Binding Domain.. Hum Mutat. 2015;36(6):599–610.

NR2E3 encodes the photoreceptor-specific nuclear hormone receptor that acts as a repressor of cone-specific gene expression in rod photoreceptors, and as an activator of several rod-specific genes. Recessive variants located in the ligand-binding domain (LBD) of NR2E3 cause enhanced short wavelength sensitive- (S-) cone syndrome (ESCS), a retinal degeneration characterized by an excess of S-cones and non-functional rods. We analyzed the dimerization properties of NR2E3 and the effect of disease-causing LBD missense variants by bioluminescence resonance energy transfer (BRET(2) ) protein interaction assays. Homodimerization was not affected in presence of p.A256V, p.R039G, p.R311Q, and p.R334G variants, but abolished in presence of p.L263P, p.L336P, p.L353V, p.R385P, and p.M407K variants. Homology modeling predicted structural changes induced by NR2E3 LBD variants. NR2E3 LBD variants did not affect interaction with CRX, but with NRL and rev-erbα/NR1D1. CRX and NRL heterodimerized more efficiently together, than did either with NR2E3. NR2E3 did not heterodimerize with TLX/NR2E1 and RXRα/NR2C1. The identification of a new compound heterozygous patient with detectable rod function, who expressed solely the p.A256V variant protein, suggests a correlation between LBD variants able to form functional NR2E3 dimers and atypical mild forms of ESCS with residual rod function.

Quiroz Y, Schultz A, Chen K, Protas H, Brickhouse M, Fleisher A, Langbaum J, Thiyyagura P, Fagan A, Shah A, Muniz M, Arboleda-Velasquez J, Munoz C, Garcia G, Acosta-Baena N, Giraldo M, Tirado V, Ramírez D, Tariot P, Dickerson B, Sperling R, Lopera F, Reiman E. Brain Imaging and Blood Biomarker Abnormalities in Children With Autosomal Dominant Alzheimer Disease: A Cross-Sectional Study.. JAMA Neurol. 2015;72(8):912–9.

IMPORTANCE: Brain imaging and fluid biomarkers are characterized in children at risk for autosomal dominant Alzheimer disease (ADAD). OBJECTIVE: To characterize and compare structural magnetic resonance imaging (MRI), resting-state and task-dependent functional MRI, and plasma amyloid-β (Aβ) measurements in presenilin 1 (PSEN1) E280A mutation-carrying and noncarrying children with ADAD. DESIGN, SETTING, AND PARTICIPANTS: Cross-sectional measures of structural and functional MRI and plasma Aβ assays were assessed in 18 PSEN1 E280A carriers and 19 noncarriers aged 9 to 17 years from a Colombian kindred with ADAD. Recruitment and data collection for this study were conducted at the University of Antioquia and the Hospital Pablo Tobon Uribe in Medellín, Colombia, between August 2011 and June 2012. MAIN OUTCOMES AND MEASURES: All participants had blood sampling, structural MRI, and functional MRI during associative memory encoding and resting-state and cognitive assessments. Outcome measures included plasma Aβ1-42 concentrations and Aβ1-42:Aβ1-40 ratios, memory encoding-dependent activation changes, resting-state connectivity, and regional gray matter volumes. Structural and functional MRI data were compared using automated brain mapping algorithms and search regions related to AD. RESULTS: Similar to findings in adult mutation carriers, in the later preclinical and clinical stages of ADAD, mutation-carrying children were distinguished from control individuals by significantly higher plasma Aβ1-42 levels (mean [SD]: carriers, 18.8 [5.1] pg/mL and noncarriers, 13.1 [3.2] pg/mL; P < .001) and Aβ1-42:Aβ1-40 ratios (mean [SD]: carriers, 0.32 [0.06] and noncarriers, 0.21 [0.03]; P < .001), as well as less memory encoding task-related deactivation in parietal regions (eg, mean [SD] parameter estimates for the right precuneus were -0.590 [0.50] for noncarriers and -0.087 [0.38] for carriers; P < .005 uncorrected). Unlike carriers in the later stages, mutation-carrying children demonstrated increased functional connectivity of the posterior cingulate cortex with medial temporal lobe regions (mean [SD] parameter estimates were 0.038 [0.070] for noncarriers and 0.190 [0.057] for carriers), as well as greater gray matter volumes in temporal regions (eg, left parahippocampus; P < . 049, corrected for multiple comparisons). CONCLUSIONS AND RELEVANCE: Children at genetic risk for ADAD have functional and structural brain changes and abnormal levels of plasma Aβ1-42. The extent to which the underlying brain changes are either neurodegenerative or developmental remains to be determined. This study provides additional information about the earliest known biomarker changes associated with ADAD.

PURPOSE: To establish the efficacy of topical N-acetylcysteine (NAC) as a treatment to reduce protein deposition on the contact lens surface. METHODS: In this prospective, nonrandomized clinical trial, a total of 10 eyes (9 patients) were enrolled from a single center. All patients had a prior ocular history of either a Boston Keratoprosthesis type I or trichiasis from Stevens-Johnson syndrome, which necessitated full-time contact lens wear. Four visits were required to complete the study. During visit 1, a new contact lens was inserted and a baseline examination was performed. Visit 2 served as the control month, whereas visits 3 and 4 were month 1 and 2 on treatment with 20% NAC. At the end of each visit the contact lens was replaced. The lenses from visit 2 (control month-without NAC) and from visit 3 (treatment month-with NAC) were collected for proteomic analysis. The main outcome measures were to quantify protein deposition, as well as to assess the visual acuity and ocular surface symptoms before and after treatment. RESULTS: Topical NAC resulted in a 20% decrease in protein deposition. This correlated with a trend for improvement in visual acuity and increased subjective improvement in vision at month 1 (P=0.0153) and 2 (P=0.0016). CONCLUSIONS: NAC reduced protein deposition, decreased ocular surface symptoms, and improved contact lens transparency, thereby providing increased optical clarity.

Fuentealba L, Rompani S, Parraguez J, Obernier K, Romero R, Cepko C, Alvarez-Buylla A. Embryonic Origin of Postnatal Neural Stem Cells.. Cell. 2015;161(7):1644–55.

Adult neural stem/progenitor (B1) cells within the walls of the lateral ventricles generate different types of neurons for the olfactory bulb (OB). The location of B1 cells determines the types of OB neurons they generate. Here we show that the majority of mouse B1 cell precursors are produced between embryonic days (E) 13.5 and 15.5 and remain largely quiescent until they become reactivated postnatally. Using a retroviral library carrying over 100,000 genetic tags, we found that B1 cells share a common progenitor with embryonic cells of the cortex, striatum, and septum, but this lineage relationship is lost before E15.5. The regional specification of B1 cells is evident as early as E11.5 and is spatially linked to the production of neurons that populate different areas of the forebrain. This study reveals an early embryonic regional specification of postnatal neural stem cells and the lineage relationship between them and embryonic progenitor cells.