Fernandez-Godino R, Pierce EA. C3a triggers formation of sub-retinal pigment epithelium deposits via the ubiquitin proteasome pathway. Sci Rep 2018;8(1):9679.Abstract
The mechanisms that connect complement system activation and basal deposit formation in early stages of age-related macular degeneration (AMD) are insufficiently understood, which complicates the design of efficient therapies to prevent disease progression. Using human fetal (hf) retinal pigment epithelial (RPE) cells, we have established an in vitro model to investigate the effect of complement C3a on RPE cells and its role in the formation of sub-RPE deposits. The results of these studies revealed that C3a produced after C3 activation is sufficient to induce the formation of sub-RPE deposits via complement-driven proteasome inhibition. C3a binds the C3a receptor (C3aR), stimulates deposition of collagens IV and VI underneath the RPE, and impairs the extracellular matrix (ECM) turnover by increased MMP-2 activity, all mediated by downregulation of the ubiquitin proteasome pathway (UPP). The formation of basal deposits can be prevented by the addition of a C3aR antagonist, which restores the UPP activity and ECM turnover. These findings indicate that the cell-based model can be used to test potential therapeutic agents in vitro. The data suggest that modulation of C3aR-mediated events could be a therapeutic approach for treatment of early AMD.
Singh AK, Phillips F, Merabet LB, Sinha P. Why Does the Cortex Reorganize after Sensory Loss?. Trends Cogn Sci 2018;22(7):569-582.Abstract
A growing body of evidence demonstrates that the brain can reorganize dramatically following sensory loss. Although the existence of such neuroplastic crossmodal changes is not in doubt, the functional significance of these changes remains unclear. The dominant belief is that reorganization is compensatory. However, results thus far do not unequivocally indicate that sensory deprivation results in markedly enhanced abilities in other senses. Here, we consider alternative reasons besides sensory compensation that might drive the brain to reorganize after sensory loss. One such possibility is that the cortex reorganizes not to confer functional benefits, but to avoid undesirable physiological consequences of sensory deafferentation. Empirical assessment of the validity of this and other possibilities defines a rich program for future research.
Oellers P, Wolkow N, Jakobiec FA, Kim IK. Hemorrhagic choroidal melanoma. Am J Ophthalmol Case Rep 2018;10:105-107.Abstract
Purpose: To demonstrate the clinical pathologic correlation in a hemorrhagic choroidal melanoma. Observations: A 52 year old patient presented with a large choroidal mass associated with vitreous and retinal hemorrhage. The eye was enucleated and histopathology demonstrated epithelioid-type MART1 positive tumor cells consistent with choroidal melanoma. The tumor had broken through Bruch's membrane, which led to localized vascular compression with bleeding into the subretinal space, retina and vitreous. Conclusions and importance: Choroidal melanoma rarely presents with hemorrhage. Tumor rupture through Bruch's membrane may result in a tourniquet effect on the tumor vasculature leading to massive hemorrhage, as in this case. A high level of clinical suspicion is required to make the diagnosis.
Lee JY, Lee JS, Materne EC, Rajala R, Ismail AM, Seto D, Dyer DW, Rajaiya J, Chodosh J. Bacterial RecA Protein Promotes Adenoviral Recombination during Infection. mSphere 2018;3(3)Abstract
Adenovirus infections in humans are common and sometimes lethal. Adenovirus-derived vectors are also commonly chosen for gene therapy in human clinical trials. We have shown in previous work that homologous recombination between adenoviral genomes of human adenovirus species D (HAdV-D), the largest and fastest growing HAdV species, is responsible for the rapid evolution of this species. Because adenovirus infection initiates in mucosal epithelia, particularly at the gastrointestinal, respiratory, genitourinary, and ocular surfaces, we sought to determine a possible role for mucosal microbiota in adenovirus genome diversity. By analysis of known recombination hot spots across 38 human adenovirus genomes in species D (HAdV-D), we identified nucleotide sequence motifs similar to bacterial Chi sequences, which facilitate homologous recombination in the presence of bacterial Rec enzymes. These motifs, referred to here as Chi, were identified immediately 5' to the sequence encoding penton base hypervariable loop 2, which expresses the arginine-glycine-aspartate moiety critical to adenoviral cellular entry. Coinfection with two HAdV-Ds in the presence of an lysate increased recombination; this was blocked in a RecA mutant strain, DH5α, or upon RecA depletion. Recombination increased in the presence of lysate despite a general reduction in viral replication. RecA colocalized with viral DNA in HAdV-D-infected cell nuclei and was shown to bind specifically to Chi sequences. These results indicate that adenoviruses may repurpose bacterial recombination machinery, a sharing of evolutionary mechanisms across a diverse microbiota, and unique example of viral commensalism. Adenoviruses are common human mucosal pathogens of the gastrointestinal, respiratory, and genitourinary tracts and ocular surface. Here, we report finding Chi-like sequences in adenovirus recombination hot spots. Adenovirus coinfection in the presence of bacterial RecA protein facilitated homologous recombination between viruses. Genetic recombination led to evolution of an important external feature on the adenoviral capsid, namely, the penton base protein hypervariable loop 2, which contains the arginine-glycine-aspartic acid motif critical to viral internalization. We speculate that free Rec proteins present in gastrointestinal secretions upon bacterial cell death facilitate the evolution of human adenoviruses through homologous recombination, an example of viral commensalism and the complexity of virus-host interactions, including regional microbiota.
Gaier ED, Wang M, Gilbert AL, Rizzo JF, Cestari DM, Miller JB. Quantitative analysis of optical coherence tomographic angiography (OCT-A) in patients with non-arteritic anterior ischemic optic neuropathy (NAION) corresponds to visual function. PLoS One 2018;13(6):e0199793.Abstract
PURPOSE: Non-arteritic anterior ischemic optic neuropathy (NAION) is the most common cause of non-glaucomatous optic neuropathy in older adults. Optical coherence tomographic angiography (OCT-A) is an emerging, non-invasive method to study the microvasculature of the posterior pole, including the optic nerve head. The goal of this study was to assess the vascular changes in the optic nerve head and peripapillary area associated with NAION using OCT-A. DESIGN: Retrospective comparative case series. METHODS: We performed OCT-A in 25 eyes (7 acute and 18 non-acute) in 19 patients with NAION. Fellow, unaffected eyes were analyzed for comparison. Patent macro- and microvascular densities were quantified in the papillary and peripapillary regions of unaffected, acutely affected, and non-acutely affected eyes and compared across these groups according to laminar segment and capillary sampling region, and with respect to performance on automated visual field testing. RESULTS: In acutely affected eyes, OCT-A revealed a reduction in the signal from the major retinal vessels and dilation of patent superficial capillaries in the peripapillary area. By contrast, non-acutely affected eyes showed attenuation of patent capillaries. The peripapillary choriocapillaris was obscured by edema in acute cases, but was similar between non-acute and unaffected eyes. The degree of dilation of the superficial microvasculature in the acute phase and attenuation in the non-acute phase each correlated inversely with visual field performance. The region of reduced patent capillary density correlated with the location of visual field defects in 80% of acute cases and 80% of non-acute cases. CONCLUSIONS: OCT-A reveals a dynamic shift in the superficial capillary network of the optic nerve head with strong functional correlates in both the acute and non-acute phases of NAION. Further study may validate OCT-A as a useful adjunctive diagnostic tool in the evaluation of ischemic optic neuropathy.
Wang JC, Rudnisky CJ, Belin MW, Ciolino JB, Group BTKS1. Outcomes of Boston keratoprosthesis type 1 reimplantation: multicentre study results. Can J Ophthalmol 2018;53(3):284-290.Abstract
OBJECTIVE: To investigate the visual and anatomical outcomes of Boston keratoprosthesis (Kpro) type 1 reimplantation. DESIGN: Subgroup analysis of multicentre prospective cohort study. PARTICIPANTS: Of 303 eyes that underwent Kpro implantation between January 2003 and July 2008 by 1 of 19 surgeons at 18 medical centres, 13 eyes of 13 patients who underwent reimplantation of Boston Kpro type 1 were compared with 13 eyes of 13 diagnosis-matched patients who underwent initial implantation. METHODS: Forms reporting preoperative, intraoperative, and postoperative parameters were prospectively collected and analyzed. Main outcome measures were Kpro retention and logMAR visual acuity. RESULTS: After a mean follow-up time of 17.1 ± 17.6 months, the retention of both initial and repeat Kpro implantation was 92.3% (12/13 in both groups), and 62% of initial implantation and 58% of repeat implantation eyes achieved visual acuity better than 20/200. Vision worse than 20/200 was often due to glaucoma or posterior segment pathology. Best-recorded logMAR visual acuity was significantly improved postoperatively in both groups (p < 0.001), and there was no statistically significant difference in final logMAR visual acuity between the 2 groups (p = 0.89). Sterile keratolysis (n = 4) and fungal infection (n = 5) were the most common causes of initial Kpro failure in the repeat Kpro group. The single failure in the repeat Kpro implantation group was due to fungal keratitis, and in the control group it was related to Kpro extrusion. CONCLUSIONS: Repeat Kpro implantation is a viable option after failed initial Kpro, with visual and anatomical outcomes comparable to those of initial procedures.
Stern JH, Tian Y, Funderburgh J, Pellegrini G, Zhang K, Goldberg JL, Ali RR, Young M, Xie Y, Temple S. Regenerating Eye Tissues to Preserve and Restore Vision. Cell Stem Cell 2018;22(6):834-849.Abstract
Ocular regenerative therapies are on track to revolutionize treatment of numerous blinding disorders, including corneal disease, cataract, glaucoma, retinitis pigmentosa, and age-related macular degeneration. A variety of transplantable products, delivered as cell suspensions or as preformed 3D structures combining cells and natural or artificial substrates, are in the pipeline. Here we review the status of clinical and preclinical studies for stem cell-based repair, covering key eye tissues from front to back, from cornea to retina, and including bioengineering approaches that advance cell product manufacturing. While recognizing the challenges, we look forward to a deep portfolio of sight-restoring, stem cell-based medicine. VIDEO ABSTRACT.
Ravindran K, Schmalz P, Torun N, Ronthal M, Chang Y-M, Thomas AJ. Angiographic Findings in the Tolosa-Hunt Syndrome and Resolution after Corticosteroid Treatment. Neuroophthalmology 2018;42(3):159-163.Abstract
The Tolosa-Hunt syndrome is a rare clinical condition characterized by painful opthalmoparesis associated with idiopathic granulomatous inflammation of the orbital apex and cavernous sinus. Historically, this condition was thought to result from arteritic changes in the internal carotid artery and cavernous sinus. Modern digital angiographic techniques were unavailable when THS was initially described, and few reports exist on its high-resolution angiographic findings. Painful ophthalmoparesis, especially of the oculomotor nerve, warrants vascular imaging because of the concern for an underlying aneurysm. Here, we describe angiographic findings of THS which may be useful for clinicians when encountering patients presenting with painful ophthalmoplegia.
Mansouri B, Roznik M, Rizzo JF, Prasad S. Rehabilitation of Visual Loss: Where We Are and Where We Need to Be. J Neuroophthalmol 2018;38(2):223-229.Abstract
BACKGROUND: Spontaneous recovery of visual loss resulting from injury to the brain is variable. A variety of traditional rehabilitative strategies, including the use of prisms or compensatory saccadic eye movements, have been used successfully to improve visual function and quality-of-life for patients with homonymous hemianopia. More recently, repetitive visual stimulation of the blind area has been reported to be of benefit in expanding the field of vision. EVIDENCE ACQUISITION: We performed a literature review with main focus on clinical studies spanning from 1963 to 2016, including 52 peer-reviewed articles, relevant cross-referenced citations, editorials, and reviews. RESULTS: Repetitive visual stimulation is reported to expand the visual field, although the interpretation of results is confounded by a variety of methodological factors and conflicting outcomes from different research groups. Many studies used subjective assessments of vision and did not include a sufficient number of subjects or controls. CONCLUSIONS: The available clinical evidence does not strongly support claims of visual restoration using repetitive visual stimulation beyond the time that spontaneous visual recovery might occur. This lack of firm supportive evidence does not preclude the potential of real benefit demonstrated in laboratories. Additional well-designed clinical studies with adequate controls and methods to record ocular fixation are needed.
Ichhpujani P, Thakur S, Kumar S, Singh RB. Juvenile Open Angle Glaucoma With Nonbullous Congenital Ichthyosiform Erythroderma. J Glaucoma 2018;27(11):e180-e182.Abstract
INTRODUCTION: Glaucoma in patients with nonbullous congenital ichthyosiform erythroderma (NBCIE) is a rare entity that has not been described in a histologically confirmed case. We present a unique case of coexisting glaucoma, ichthyosis, and dwarfism that has not been previously described. METHODS: We present a case of NBCIE with glaucoma and dwarfism that presented to our outpatient department. The patient was referred for watering and photophobia that were due to an epithelial defect that was subsequently managed conservatively. Investigations revealed the existence of a constellation of findings that are presented here. RESULTS: NBCIE, glaucoma, and dwarfism represent a spectrum of diseases that seem to have a syndromic association. More gene linkage-based analysis are, however, needed to further confirm our observations. CONCLUSIONS: NBCIE, glaucoma, and dwarfism can often occur together and need to be assessed and managed individually. Early diagnosis of this spectrum can help improve patient management and quality of life. Dermatologists must get an ocular examination conducted for icthyoses patients.
Dabul ANG, Avaca-Crusca JS, Van Tyne D, Gilmore MS, Camargo ILBC. Resistance in In Vitro Selected Tigecycline-Resistant Methicillin-Resistant Staphylococcus aureus Sequence Type 5 Is Driven by Mutations in mepR and mepA Genes. Microb Drug Resist 2018;24(5):519-526.Abstract
A tigecycline-susceptible (TGC-S) Sequence Type (ST) 5 clinical methicillin-resistant Staphylococcus aureus (MRSA) strain was cultured in escalating levels of tigecycline, yielding mutants eightfold more resistant. Their genomes were sequenced to identify genetic alterations, resulting in resistance. Alterations in rpsJ, commonly related to tigecycline resistance, were also investigated. Tigecycline resistance was mediated by loss-of-function mutations in the transcriptional repressor mepR, resulting in derepression of the efflux pump mepA. Increased levels of resistance were obtained by successive mutations in mepA itself. No alterations in RpsJ were observed in selected strains, but we observed a K57M substitution, previously correlated with resistance, among TGC-S clinical strains. Thus, the pathway to tigecycline resistance in CC5 MRSA in vitro appears to be derepression of mep operon as the result of mepR loss-of-function mutation, followed by alterations in MepA efflux pump. This shows that other evolutionary pathways, besides mutation of rpsJ, are available for evolving tigecycline resistance in CC5 MRSA.
Shoji MK, Saeed HN, Habib LA, Freitag SK. Epibulbar Mass With Upper Eyelid Cleft and Focal Scalp Alopecia in a Neonate: A New Case of Oculoectodermal Syndrome. Ophthalmic Plast Reconstr Surg 2018;34(4):e133-e136.Abstract
A female neonate presented with a pedunculated left lateral epibulbar mass protruding through the eyelids that originated from the temporal cornea and superolateral bulbar and palpebral conjunctiva. She had a cleft in the ipsilateral central upper eyelid with horizontal kink of the tarsus lateral to the cleft and focal patches of alopecia on the scalp. Histopathology of the epibulbar mass revealed conjunctival epithelium with underlying connective tissue, cartilage, bone, adipose, and lacrimal gland consistent with epibulbar dermoid. Genetic testing of the surgical specimen was positive for a KRAS mutation at position 146. MRI showed subarachnoid asymmetry around the left temporal lobe and a C1-C2 enhancing lesion. These clinical and molecular findings suggest that this patient has a new clinical variant of oculoectodermal syndrome, a rare disorder associated with somatic KRAS gene mutations and characterized clinically by epibulbar dermoids, alopecia, aplasia cutis, brain anomalies, umbilical hernias, and congenital heart defects.
O'Connell AE, Zhou F, Shah MS, Murphy Q, Rickner H, Kelsen J, Boyle J, Doyle JJ, Gangwani B, Thiagarajah JR, Kamin DS, Goldsmith JD, Richmond C, Breault DT, Agrawal PB. Neonatal-Onset Chronic Diarrhea Caused by Homozygous Nonsense WNT2B Mutations. Am J Hum Genet 2018;103(1):131-137.Abstract
Homozygous nonsense mutations in WNT2B were identified in three individuals from two unrelated families with severe, neonatal-onset osmotic diarrhea after whole-exome sequencing was performed on trios from the two families. Intestinal biopsy samples from affected individuals were used for histology and immunofluorescence and to generate enteroids ex vivo. Histopathologic evaluation demonstrated chronic inflammatory changes in the stomach, duodenum, and colon. Immunofluorescence demonstrated diminished staining for OLFM4, a marker for intestinal stem cells (ISCs). The enteroids generated from WNT2B-deficient intestinal epithelium could not be expanded and did not survive passage. Addition of CHIR-99021 (a GSK3A and GSK3B inhibitor and activator of canonical WNT/β-CATENIN signaling) could not rescue WNT2B-deficient enteroids. Addition of supplemental recombinant murine WNT2B was able to perpetuate small enteroids for multiple passages but failed to expand their number. Enteroids showed a 10-fold increase in the expression of LEF1 mRNA and a 100-fold reduction in TLR4 expression, compared with controls by quantitative RT-PCR, indicating alterations in canonical WNT and microbial pattern-recognition signaling. In summary, individuals with homozygous nonsense mutations in WNT2B demonstrate severe intestinal dysregulation associated with decreased ISC number and function, likely explaining their diarrheal phenotype. WNT2B deficiency should be considered for individuals with neonatal-onset diarrhea.
Kumar S, Ichhpujani P, Thakur S, Singh RB. Traumatic corneal perforation with exteriorisation of Ahmed glaucoma valve tube. BMJ Case Rep 2018;2018Abstract
We report a rare case of traumatic corneal perforation with Ahmed glaucoma valve (AGV) tube. A 5-year-old female child, diagnosed with refractory glaucoma, had undergone AGV implantation, presented with the posterior migration of AGV tube after trauma to the eye. The detailed ocular history, ophthalmic findings, clinical course and surgical management are discussed.