Tailored vs Static Oxygen Saturation Targets to Prevent Retinopathy of Prematurity. JAMA Ophthalmol 2019;.
Steatocystoma Simplex of the Caruncle: Case Report and Immunohistologic Study. Ophthalmic Plast Reconstr Surg 2019;35(2):e45-e47.Abstract.
A yellow cystic lesion of the caruncle in a 23-year-old woman proved to be a solitary steatocystoma, a rare occurrence in that location. While the histopathologic diagnosis was evident from clusters of sebaceous cells within the cyst wall, a panel of immunohistochemical stains further distinguished the lesion from a keratinous cyst. The most useful stains for differentiating the two conditions were carcinoembryonic antigen, epithelial membrane antigen, cytokeratins 17 and 19, and calretinin. Only three previous cases of caruncular steatocystoma simplex have been reported, none of which included immunohistochemical studies. The current findings support the origin of the cyst from the small duct that connects the unilobular sebaceous gland associated with vellus hairs to the follicular canal.
Intravenous treatment of choroidal neovascularization by photo-targeted nanoparticles. Nat Commun 2019;10(1):804.Abstract.
Choroidal neovascularization (CNV) is the major cause of vision loss in wet age-related macular degeneration (AMD). Current therapies require repeated intravitreal injections, which are painful and can cause infection, bleeding, and retinal detachment. Here we develop nanoparticles (NP-[CPP]) that can be administered intravenously and allow local drug delivery to the diseased choroid via light-triggered targeting. NP-[CPP] is formed by PEG-PLA chains modified with a cell penetrating peptide (CPP). Attachment of a DEACM photocleavable group to the CPP inhibits cellular uptake of NP-[CPP]. Irradiation with blue light cleaves DEACM from the CPP, allowing the CPP to migrate from the NP core to the surface, rendering it active. In mice with laser-induced CNV, intravenous injection of NP-[CPP] coupled to irradiation of the eye allows NP accumulation in the neovascular lesions. When loaded with doxorubicin, irradiated NP-[CPP] significantly reduces neovascular lesion size. We propose a strategy for non-invasive treatment of CNV and enhanced drug accumulation specifically in diseased areas of the eye.
Microperimetry in age-related macular degeneration: association with macular morphology assessed by optical coherence tomography. Br J Ophthalmol 2019;103(12):1769-1776.Abstract.
BACKGROUND/AIMS: Microperimetry is a technique that is increasingly used to assess visual function in age-related macular degeneration (AMD). In this study, we aimed to evaluate the relationship between retinal sensitivity measured with macular integrity assessment (MAIA) microperimetry and optical coherence tomography (OCT)-based macular morphology in AMD. METHODS: Prospective, cross-sectional study. All participants were imaged with colour fundus photographs used for AMD staging (Age-Related Eye Disease Study scale), spectral-domain OCT (Spectralis, Heidelberg, Germany) and swept-source OCT (Topcon, Japan). Threshold retinal sensitivity of the central 10° diameter circle was assessed with the full-threshold, 37-point protocol of the MAIA microperimetry device (Centervue, Italy). Univariable and multivariable multilevel mixed-effect linear regression models were used for analysis. RESULTS: We included 102 eyes with AMD and 46 control eyes. Multivariable analysis revealed that older age (p<0.0001), advanced AMD stage (p<0.0001) and reduced retinal thickness (p<0.0001) were associated with decreased mean retinal sensitivity. No associations were found between choroidal thickness and retinal sensitivity within the macula. Within the 10° diameter circle of the macula, the presence of ellipsoid disruption, subretinal fluid, atrophy and fibrosis, and outer retinal tubulation on OCT images was also associated with decreased retinal sensitivity (all p<0.05). CONCLUSIONS: There is an association between TRS as determined by MAIA microperimetry and several OCT structural parameters across various stages of AMD. This study highlights the relevance of microperimetry as a functional outcome measure for AMD.
Tolerability and Functionality of a Wireless 24-Hour Ocular Telemetry Sensor in African American Glaucoma Patients. J Glaucoma 2019;28(2):119-124.Abstract.
PURPOSE: The purpose of the study was to evaluate the tolerability and functionality of a wireless ocular telemetry sensor in African American patients with glaucoma. MATERIALS AND METHODS: In this prospective, observational cohort study, 20 African American patients with primary open angle glaucoma (POAG) were evaluated at the University of Colorado Eye Center. Before lens placement, patients recorded ocular comfort and underwent a baseline eye exam. Following the exam, patients were fitted with a SENSIMED Triggerfish contact lens sensor and data recording device. Patients were sent home and instructed to record their activities in a journal and return in 24 hours. Repeat exams were performed at various time points in clinic before and after lens removal. RESULTS: All 20 patients retained the lens for the 24-hour study period. The patient reported comfort was excellent, with a nadir of mean recorded comfort of 7.05/10. Significant clinical changes were noted in lid/conjunctival erythema, BCVA, refraction, and pachymetry over the course of lens wear. The majority of these changes were improved or resolved by 1 hour after lens removal. Voltage output was significantly greater nocturnally than diurnally (184.79 mV and 71.48 mV, respectively; P<0.0001). There was no significant change in signal variability or slope over the entire duration of the sleep/wake period based on sleep. CONCLUSIONS: The wireless ocular sensor is well tolerated over a 24-hour period in African American patients with POAG despite transient changes in visual acuity and conjunctival erythema. Clinically usable 24-hour profiles were generated for all patients, with voltage output increasing significantly during periods of sleep.
APOPTOSIS AND ANGIOFIBROSIS IN DIABETIC TRACTIONAL MEMBRANES AFTER VASCULAR ENDOTHELIAL GROWTH FACTOR INHIBITION: Results of a Prospective Trial. Report No. 2. Retina 2019;39(2):265-273.Abstract.
PURPOSE: We sought to characterize the angiofibrotic and apoptotic effects of vascular endothelial growth factor (VEGF)-inhibition on fibrovascular epiretinal membranes in eyes with traction retinal detachment because of proliferative diabetic retinopathy. METHODS: Membranes were excised from 20 eyes of 19 patients (10 randomized to intravitreal bevacizumab, 10 controls) at vitrectomy. Membranes were stained with antibodies targeting connective tissue growth factor (CTGF) or VEGF and colabeled with antibodies directed against endothelial cells (CD31), myofibroblasts, or retinal pigment epithelium markers. Quantitative and colocalization analyses of antibody labeling were obtained through immunofluorescence confocal microscopy. Masson trichrome staining, cell counting of hematoxylin and eosin sections, and terminal dUTP nick-end labeling staining were performed. RESULTS: High levels of fibrosis were observed in both groups. Cell apoptosis was higher (P = 0.05) in bevacizumab-treated membranes compared with controls. The bevacizumab group had a nonsignificant reduction in colocalization in CD31-CTGF and cytokeratin-VEGF studies compared with controls. Vascular endothelial growth factor in extracted membranes was positively correlated with vitreous levels of VEGF; CTGF in extracted membranes was negatively correlated with vitreous levels of CTGF. CONCLUSION: Bevacizumab suppresses vitreous VEGF levels, but does not significantly alter VEGF or CTGF in diabetic membranes that may be explained by high baseline levels of fibrosis. Bevacizumab may cause apoptosis within fibrovascular membranes.
Finding an Optimal Corneal Xenograft Using Comparative Analysis of Corneal Matrix Proteins Across Species. Sci Rep 2019;9(1):1876.Abstract.
Numerous animal species have been proposed as sources of corneal tissue for obtaining decellularized xenografts. The selection of an appropriate animal model must take into consideration the differences in the composition and structure of corneal proteins between humans and other animal species in order to minimize immune response and improve outcome of the xenotransplant. Here, we compared the amino-acid sequences of 16 proteins present in the corneal stromal matrix of 14 different animal species using Basic Local Alignment Search Tool, and calculated a similarity score compared to the respective human sequence. Primary amino acid structures, isoelectric point and grand average of hydropathy (GRAVY) values of the 7 most abundant proteins (i.e. collagen α-1 (I), α-1 (VI), α-2 (I) and α-3 (VI), as well as decorin, lumican, and keratocan) were also extracted and compared to those of human. The pig had the highest similarity score (91.8%). All species showed a lower proline content compared to human. Isoelectric point of pig (7.1) was the closest to the human. Most species have higher GRAVY values compared to human except horse. Our results suggest that porcine cornea has a higher relative suitability for corneal transplantation into humans compared to other studied species.
Neuroprotective effects of PPARα in retinopathy of type 1 diabetes. PLoS One 2019;14(2):e0208399.Abstract.
Diabetic retinopathy (DR) is a common neurovascular complication of type 1 diabetes. Current therapeutics target neovascularization characteristic of end-stage disease, but are associated with significant adverse effects. Targeting early events of DR such as neurodegeneration may lead to safer and more effective approaches to treatment. Two independent prospective clinical trials unexpectedly identified that the PPARα agonist fenofibrate had unprecedented therapeutic effects in DR, but gave little insight into the physiological and molecular mechanisms of action. The objective of the present study was to evaluate potential neuroprotective effects of PPARα in DR, and subsequently to identify the responsible mechanism of action. Here we reveal that activation of PPARα had a robust protective effect on retinal function as shown by Optokinetic tracking in a rat model of type 1 diabetes, and also decreased retinal cell death, as demonstrated by a DNA fragmentation ELISA. Further, PPARα ablation exacerbated diabetes-induced decline of visual function as demonstrated by ERG analysis. We further found that PPARα improved mitochondrial efficiency in DR, and decreased ROS production and cell death in cultured retinal neurons. Oxidative stress biomarkers were elevated in diabetic Pparα-/- mice, suggesting increased oxidative stress. Mitochondrially mediated apoptosis and oxidative stress secondary to mitochondrial dysfunction contribute to neurodegeneration in DR. Taken together, these findings identify a robust neuroprotective effect for PPARα in DR, which may be due to improved mitochondrial function and subsequent alleviation of energetic deficits, oxidative stress and mitochondrially mediated apoptosis.
Emerging roles for insulin-like growth factor binding protein like protein 1. Neural Regen Res 2019;14(2):258-259..
Predictors of Primary Intracranial Hypertension in Children Using a Newly Suggested Opening Pressure Cutoff of 280 mm HO. Pediatr Neurol 2019;91:27-33.Abstract.
OBJECTIVES: We assessed the clinical characteristics of primary intracranial hypertension (PIH) in children using a newly recommended threshold for cerebrospinal fluid opening pressure (280 mm HO). METHOD: Cross-sectional study of patients age ≤21 years who had a lumbar puncture done for evaluation of PIH. Patients were excluded if lumbar puncture was done for a suspected infection, seizure, mental status changes, multiple sclerosis, or Guillain-Barre syndrome. Cases were identified using a text-search module followed by manual review. We performed χ2 analysis for categorical data and Mann-Whitney U test for continuous data, followed by a binary logistic regression. RESULTS: We identified 374 patients of whom 67% were female, median age was 13 years interquartile range (11 to 16 years), and admission rate was 24%. Using an opening pressure cutoff of 250 mm HO, 127 patients (34%) were identified as having PIH, whereas using the new cutoff 105 patients (28%) met PIH criteria. Predictors for PIH included optic disc edema or sixth nerve palsy using both old, odds ratio (OR) 7.6 (4.3, 13.5), and new cutoffs, OR 9.7 (95% confidence interval 5.1, 18.5). Headache duration ≤61 days is predictive of PIH using the new cutoff OR 4.1 (95% confidence interval 1.3, 12.8). A model is presented which stratifies patients into groups with low (7%), medium (18%), and high (greater than 42%) risk of PIH. CONCLUSIONS: A higher cerebrospinal fluid opening pressure threshold in the criteria of PIH is associated with PIH patients with a different symptom profile. Children with optic disc edema, bulging fontanel or sixth nerve palsy, are at increased risk for PIH.
The Genetic Influence on Corticosteroid-Induced Ocular Hypertension: A Field Positioned for Discovery. Am J Ophthalmol 2019;202:1-5.Abstract.
PURPOSE: To provide evidence that corticosteroid-induced ocular hypertension has a genetic component. DESIGN: Evidence-based perspective. METHODS: We conducted a comprehensive literature search for studies exploring genetic influences on intraocular pressure responses to corticosteroid treatment. RESULTS: Studies demonstrating increased risk of corticosteroid-induced ocular hypertension among first-degree relatives of affected individuals support a genetic contribution to the disease. Family and personal history of primary open-angle glaucoma also increases the risk of corticosteroid-induced intraocular pressure elevation, suggesting common genetic etiologies. A number of studies have attempted to identify predisposing genetic factors; however, reproducible findings have not yet been reported. The recent availability of large data sets with clinical and genetic data for patients affected by corticosteroid-induced ocular hypertension and glaucoma provides new opportunities to study the genetic underpinnings of this important condition. CONCLUSIONS: There is substantial evidence suggesting a genetic component to corticosteroid-related ocular hypertension and glaucoma, but specific genetic risk factors have yet to be identified. The current confluence of large genetic data sets and affordable genetic sequencing technologies has great potential for discovering the genes that increase risk for this blinding complication of corticosteroid therapy.
Periocular Triamcinolone vs. Intravitreal Triamcinolone vs. Intravitreal Dexamethasone Implant for the Treatment of Uveitic Macular Edema: The PeriOcular vs. INTravitreal corticosteroids for uveitic macular edema (POINT) Trial. Ophthalmology 2019;126(2):283-295.Abstract.
PURPOSE: To evaluate the comparative effectiveness of 3 regional corticosteroid injections for uveitic macular edema (ME): periocular triamcinolone acetonide (PTA), intravitreal triamcinolone acetonide (ITA), and the intravitreal dexamethasone implant (IDI). DESIGN: Multicenter, randomized clinical trial. PARTICIPANTS: Patients with uveitic ME. METHODS: Patients were randomized 1:1:1 to receive 1 of the 3 therapies. Patients with bilateral ME were assigned the same treatment for both eyes. MAIN OUTCOME MEASURES: The primary outcome was the proportion of baseline (PropBL) central subfield thickness (CST) at 8 weeks (CST at 8 weeks/CST at baseline) assessed with OCT by masked readers. Secondary outcomes included ≥20% improvement and resolution of ME, best-corrected visual acuity (BCVA), and intraocular pressure (IOP) events over 24 weeks. RESULTS: All treatment groups demonstrated improved CST during follow-up. At 8 weeks, each group had clinically meaningful reductions in CST relative to baseline (PropBL: 0.77, 0.61, and 0.54, respectively, which translates to reductions of 23%, 39%, and 46% for PTA, ITA, and IDI, respectively). Intravitreal triamcinolone acetonide (PropBL ITA/PropBL PTA, hazard ratio [HR], 0.79; 99.87% confidence interval [CI], 0.65-0.96) and IDI (PropBL IDI/PropBL PTA, HR, 0.69; 99.87% CI, 0.56-0.86) had larger reductions in CST than PTA (P < 0.0001). Intravitreal dexamethasone implant was noninferior to ITA at 8 weeks (PropBL IDI/PropBL ITA, HR, 0.88; 99.87% CI, 0.71-1.08). Both ITA and IDI treatments also were superior to PTA treatment in improving and resolving uveitic ME. All treatment groups demonstrated BCVA improvement throughout follow-up. Both ITA and IDI groups had improvements in BCVA that was 5 letters greater than in the PTA group at 8 weeks (P < 0.004). The risk of having IOP ≥24 mmHg was higher in the intravitreal treatment groups compared with the periocular group (HR, 1.83; 95% CI, 0.91-3.65 and HR, 2.52; 95% CI, 1.29-4.91 for ITA and IDI, respectively); however, there was no significant difference between the 2 intravitreal treatment groups. CONCLUSIONS: Intravitreal triamcinolone acetonide and the IDI were superior to PTA for treating uveitic ME with modest increases in the risk of IOP elevation. This risk did not differ significantly between intravitreal treatments.
PolyGlcNAc-containing exopolymers enable surface penetration by non-motile Enterococcus faecalis. PLoS Pathog 2019;15(2):e1007571.Abstract.
Bacterial pathogens have evolved strategies that enable them to invade tissues and spread within the host. Enterococcus faecalis is a leading cause of local and disseminated multidrug-resistant hospital infections, but the molecular mechanisms used by this non-motile bacterium to penetrate surfaces and translocate through tissues remain largely unexplored. Here we present experimental evidence indicating that E. faecalis generates exopolysaccharides containing β-1,6-linked poly-N-acetylglucosamine (polyGlcNAc) as a mechanism to successfully penetrate semisolid surfaces and translocate through human epithelial cell monolayers. Genetic screening and molecular analyses of mutant strains identified glnA, rpiA and epaX as genes critically required for optimal E. faecalis penetration and translocation. Mechanistically, GlnA and RpiA cooperated to generate uridine diphosphate N-acetylglucosamine (UDP-GlcNAc) that was utilized by EpaX to synthesize polyGlcNAc-containing polymers. Notably, exogenous supplementation with polymeric N-acetylglucosamine (PNAG) restored surface penetration by E. faecalis mutants devoid of EpaX. Our study uncovers an unexpected mechanism whereby the RpiA-GlnA-EpaX metabolic axis enables production of polyGlcNAc-containing polysaccharides that endow E. faecalis with the ability to penetrate surfaces. Hence, targeting carbohydrate metabolism or inhibiting biosynthesis of polyGlcNAc-containing exopolymers may represent a new strategy to more effectively confront enterococcal infections in the clinic.
Modes of Accessing Bicarbonate for the Regulation of Membrane Guanylate Cyclase (ROS-GC) in Retinal Rods and Cones. eNeuro 2019;6(1)Abstract.
The membrane guanylate cyclase, ROS-GC, that synthesizes cyclic GMP for use as a second messenger for visual transduction in retinal rods and cones, is stimulated by bicarbonate. Bicarbonate acts directly on ROS-GC1, because it enhanced the enzymatic activity of a purified, recombinant fragment of bovine ROS-GC1 consisting solely of the core catalytic domain. Moreover, recombinant ROS-GC1 proved to be a true sensor of bicarbonate, rather than a sensor for CO. Access to bicarbonate differed in rods and cones of larval salamander, , of unknown sex. In rods, bicarbonate entered at the synapse and diffused to the outer segment, where it was removed by Cl-dependent exchange. In contrast, cones generated bicarbonate internally from endogenous CO or from exogenous CO that was present in extracellular solutions of bicarbonate. Bicarbonate production from both sources of CO was blocked by the carbonic anhydrase inhibitor, acetazolamide. Carbonic anhydrase II expression was verified immunohistochemically in cones but not in rods. In addition, cones acquired bicarbonate at their outer segments as well as at their inner segments. The multiple pathways for access in cones may support greater uptake of bicarbonate than in rods and buffer changes in its intracellular concentration.
Assessment of Infraorbital Hypesthesia Following Orbital Floor and Zygomaticomaxillary Complex Fractures Using a Novel Sensory Grading System. Ophthalmic Plast Reconstr Surg 2019;35(1):53-55.Abstract.
PURPOSE: Introduction of a novel sensory grading system to assess the incidence and long-term recovery of infraorbital hypesthesia following orbital floor and inferior orbital rim fractures. METHODS: Patients who presented for evaluation of orbital floor and/or zygomaticomaxillary complex (ZMC) fractures between January 2015 and April 2016 were analyzed. Two-point subjective infraorbital sensory grading in 5 discrete anatomic areas was performed. Fractures were repaired based on traditional criteria; hypesthesia was not an indication for surgery. The sensory grading system was repeated a mean 21.7 months (range 18-28) after initial fracture. RESULTS: Sixty-two patients (mean 41.8 years) participated in the initial symptom grading, and 42 patients (67.7%) completed the 2-year follow-up. Overall, 20 of 42 patients (47.6%) had some infraorbital hypesthesia. There were fewer with isolated orbital floor fractures versus ZMC fractures (31.8% vs. 68.4%; p = 0.019). Two years postinjury, 9.1% and 40.0% with isolated floor and ZMC fractures, respectively, had persistent sensory disturbance (p = 0.0188). Of patients with sensory disturbance on presentation, 71.4% with isolated floor fractures and 38.5% with ZMC fractures experienced complete sensory recovery (p = 0.1596). Patients with isolated floor fractures had improved recovery after surgery (100% vs. 33.3% recovery; p = 0.0410). Patients with ZMC fractures showed no difference in sensory prognosis between those repaired and observed. CONCLUSIONS: In this pilot study, isolated orbital floor fractures carried a good infraorbital sensory prognosis, further improved by surgical repair. Zygomaticomaxillary complex fractures portended a worse long-term sensory outcome, unaffected by management strategy. This study validates the novel sensory grading system in post-fracture analysis.