2014

Streptococcus pneumoniae, an inhabitant of the upper respiratory mucosa, causes respiratory and invasive infections as well as conjunctivitis. Strains that lack the capsule, a main virulence factor and the target of current vaccines, are often isolated from conjunctivitis cases. Here we perform a comparative genomic analysis of 271 strains of conjunctivitis-causing S. pneumoniae from 72 postal codes in the United States. We find that the vast majority of conjunctivitis strains are members of a distinct cluster of closely related unencapsulated strains. These strains possess divergent forms of pneumococcal virulence factors (such as CbpA and neuraminidases) that are not shared with other unencapsulated nasopharyngeal S. pneumoniae. They also possess putative adhesins that have not been described in encapsulated pneumococci. These findings suggest that the unencapsulated strains capable of causing conjunctivitis utilize a pathogenesis strategy substantially different from that described for S. pneumoniae at other infection sites.

The intestinal microbial ecosystem is complex, and few of the principles that contribute to homeostasis in health are well understood. Pham et al. (2014) show that a network including the epithelial interleukin-22 receptor protects against infection with the opportunistic pathogen Enterococcus faecalis through promotion of host-microbiota mutualism.

PURPOSE. Canonical Wnt signaling has emerged as a critical regulator of aqueous outflow facility and intraocular pressure (IOP). In this study, we examine the role of canonical Wnt signaling on extracellular matrix (ECM) expression in the trabecular meshwork (TM) and explore the molecular mechanisms involved. METHODS. β-catenin localization in human TM tissue was examined using immunofluorescent staining. Primary human TM cells were incubated with lithium chloride (LiCl) and the effect on active β-catenin expression was assessed by immunoblot. Adenovirus expressing a dominant-negative TCF4 mutant that lacks a β-catenin binding domain was used. Changes in the levels of the microRNA-29 (miR-29) family and ECM proteins were determined by real-time quantitative PCR and immunoblot analysis, respectively. RESULTS. β-catenin was expressed throughout the TM, with localization primarily to the plasma membrane. Incubation of TM cells with lithium chloride increased the expression of active β-catenin. Lithium chloride treatment upregulated miR-29b expression, and suppressed the levels of various ECM proteins under both basal and TGF-β2 stimulatory conditions. Infection of TM cells with a dominant-negative TCF4 mutant induced ECM levels without a significant change in the expression of the miR-29 family. CONCLUSIONS. Collectively, our data identify the canonical Wnt signaling pathway as an important modulator of ECM expression in the TM and provide a mechanistic framework for its regulation of outflow facility and IOP.

Neuroimmunologic and systemic rheumatic diseases are frequently accompanied by inflammation of the eye, ocular adnexa, and orbital tissues. An understanding of the diverse forms of ophthalmic pathology in these conditions aids the clinician in making appropriate preventative, diagnostic, therapeutic, and prognostic decisions. In this review, the authors address ocular inflammation in neurorheumatic disease in three sections: first, they highlight current perspectives on immune mechanisms in the development of these disorders; next, they provide a framework for the recognition and evaluation of ophthalmologic inflammatory entities; finally, they discuss in detail several inflammatory conditions that affect the nervous system and the eye, emphasizing the features that should alert neurologists to initiate ophthalmologic evaluation. The conditions discussed include multiple sclerosis, neuromyelitis optica, chronic relapsing inflammatory optic neuropathy, Susac syndrome, Cogan syndrome, acute posterior multifocal placoid pigment epitheliopathy, Vogt-Koyanagi-Harada disease, Behçet disease, sarcoidosis, systemic lupus erythematosus, granulomatosis with polyangiitis (Wegener granulomatosis), polyarteritis nodosa, giant cell arteritis, IgG4-related disease, and Sjögren syndrome.

The characterization of genes responsible for glaucoma is the critical first step toward the development of gene-based diagnostic and screening tests, which could identify individuals at risk for disease before irreversible optic nerve damage occurs. Early-onset forms of glaucoma affecting children and young adults are typically inherited as Mendelian autosomal dominant or recessive traits whereas glaucoma affecting older adults has complex inheritance. In this report, we present a comprehensive overview of the genes and genomic regions contributing to inherited glaucoma.

PURPOSE: To correlate the clinical, radiographic, histopathologic, and immunohistochemical features of 5 primary periorbital intraosseous cavernous vascular malformations. DESIGN: Retrospective interventional case series. METHODS: Clinical and operative records and radiographic images were reviewed. Histopathologic slides were evaluated with hematoxylin-eosin, trichrome, and elastin stains. Immunohistochemical studies were performed with a spectrum of monoclonal antibodies directed at antigens of vascular cells. RESULTS: Three men and 2 women ranged in age from 36 to 64 years. Vision was unaffected and there was no proptosis or globe displacement. The slow-growing lesions measured 13-25 mm in greatest diameter (mean 16.4 mm). Computed tomographic studies revealed that 2 lesions were situated in the maxillary bone, 2 in the frontal, and 1 in the zygoma, all anteriorly and with circumscribed, lucent, honeycombed, or sunburst characteristics. Histopathologically the lesions were composed of cavernous or telangiectatic channels; 1 showed advanced fibrotic vascular involution. Immunohistochemistry demonstrated CD31/34 positivity for vascular endothelium and D2-40 negativity for lymphatic endothelium. A typically thin mural myofibroblastic cuff was smooth muscle actin positive, weakly calponin positive, and desmin negative. Glucose transporter-1 and Ki-67 were negative in the endothelium. CONCLUSIONS: Intraosseous vascular lesions resemble orbital cavernous venous malformations (not true hemangiomas), except that their vascular walls are thinner owing to the constraints imposed by neighboring bone spicules, which limit the amount of interstitium from which mural myofibroblasts can be recruited. The bony trabeculae conferred the honeycomb or sunburst appearances observed radiographically. En bloc excision of these lesions was successful and avoided complications (mean follow-up, 46 months).

Purpose: Patients with macular disease often report experiencing metamorphopsia (visual distortion). Although typically measured with Amsler charts, more objective and quantitative assessments of perceived distortion are desirable to effectively monitor the presence, progression and remediation of visual impairment. Methods: Participants with binocular (n = 33) and monocular (n= 50) maculopathy across seven disease groups, and control participants (n = 10) with no identifiable retinal disease completed a modified Amsler Grid assessment (presented on a computer screen with eye tracking to ensure fixation compliance) and two novel objective measures of metamorphopsia in the central five degrees of visual field. 81% (67/83) of participants completed a task requiring them to configure eight dots in the shape of a square, and 64% (32/50) of participants experiencing monocular distortion completed a spatial alignment task using dichoptic stimuli. 10 controls completed all tasks. Results: Horizontal and vertical distortion magnitudes were calculated for each of the three assessments. Distortion magnitudes were significantly higher in patients than controls in all assessments. There was no significant difference in magnitude of distortion across different macular diseases. Among patients, there were no significant correlations between overall magnitude of distortion among any of the three measures and no significant correlations in localized measures of distortion. Conclusions: Three alternative quantifications of monocular spatial distortion in the central visual field generated uncorrelated estimates of visual distortion. It is therefore unlikely that metamorphopsia is caused solely by displacement of photoreceptors in the retina, but instead involves additional top-down information, knowledge about the scene, and perhaps, cortical reorganization.

Acuity is the most commonly used measure of visual function, and reductions in acuity are associated with most eye diseases. Metamorphopsia-a perceived distortion of visual space-is another common symptom of visual impairment and is currently assessed qualitatively using Amsler (1953) charts. In order to quantify the impact of metamorphopsia on acuity, we measured the effect of physical spatial distortion on letter recognition. Following earlier work showing that letter recognition is tuned to specific spatial frequency (SF) channels, we hypothesized that the effect of distortion might depend on the spatial scale of visual distortion just as it depends on the spatial scale of masking noise. Six normally sighted observers completed a 26 alternate forced choice (AFC) Sloan letter identification task at five different viewing distances, and the letters underwent different levels of spatial distortion. Distortion was controlled using spatially band-pass filtered noise that spatially remapped pixel locations. Noise was varied over five spatial frequencies and five magnitudes. Performance was modeled with logistic regression and worsened linearly with increasing distortion magnitude and decreasing letter size. We found that retinal SF affects distortion at midrange frequencies and can be explained with the tuning of a basic contrast sensitivity function, while object-centered distortion SF follows a similar pattern of letter object recognition sensitivity and is tuned to approximately three cycles per letter (CPL). The interaction between letter size and distortion makes acuity an unreliable outcome for metamorphopsia assessment.

Variants in LOXL1 are significantly associated with exfoliation syndrome (XFS), however the impact of the associated variants on disease development is not yet understood. Initially the associated missense changes, R141L and G153D, were considered to be pathogenic alleles. Flipping of the risk allele in certain populations for both missense variants provided strong evidence that these missense changes are not biologically significant and suggest that other LOXL1 variant(s), in linkage disequilibrium with these missense variants, predispose to exfoliation syndrome by affecting gene expression or protein function. Several lines of evidence support dysregulation of LOXL1 gene expression as a contributing factor to disease development. First, in the German population the R141L (rs1048661) risk allele reduced LOXL1 expression by 20%. Second, haplotype analysis identified a risk haplotype that includes including R141L, G153D, as well as a LOXL1 promoter region variant previously shown to reduce gene expression (rs16958477). Third, the LOXL1 risk haplotype influences gene expression induced by disease-associated factors TGF-B1, oxidative stress, UV light and hypoxia. Finally, a LOXL1 null mouse has some features of XFS suggesting that decreased enzyme activity contributes to predisposition to the disease. Collectively, these results suggest that dysregulation of LOXL1 expression is a contributing factor to exfoliation disease development.