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2014

Valdez C, Arboleda-Velasquez J, Amarnani D, Kim L, D’Amore P. Retinal microangiopathy in a mouse model of inducible mural cell loss. Am J Pathol. 2014;184(10):2618–26.
Diabetes can lead to vision loss because of progressive degeneration of the neurovascular unit in the retina, a condition known as diabetic retinopathy. In its early stages, the pathology is characterized by microangiopathies, including microaneurysms, microhemorrhages, and nerve layer infarcts known as cotton-wool spots. Analyses of postmortem human retinal tissue and retinas from animal models indicate that degeneration of the pericytes, which constitute the outer layer of capillaries, is an early event in diabetic retinopathy; however, the relative contribution of specific cellular components to the pathobiology of diabetic retinopathy remains to be defined. We investigated the phenotypic consequences of pericyte death on retinal microvascular integrity by using nondiabetic mice conditionally expressing a diphtheria toxin receptor in mural cells. Five days after administering diphtheria toxin in these adult mice, changes were observed in the retinal vasculature that were similar to those observed in diabetes, including microaneurysms and increased vascular permeability, suggesting that pericyte cell loss is sufficient to trigger retinal microvascular degeneration. Therapies aimed at preventing or delaying pericyte dropout may avoid or attenuate the retinal microangiopathy associated with diabetes.
Song D, Grieco S, Li Y, Hunter A, Chu S, Zhao L, Song Y, DeAngelis R, Shi LY, Liu Q, Pierce E, Nishina P, Lambris J, Dunaief J. A murine RP1 missense mutation causes protein mislocalization and slowly progressive photoreceptor degeneration. Am J Pathol. 2014;184(10):2721–9.
Mutations in the RP1 gene can cause retinitis pigmentosa. We identified a spontaneous L66P mutation caused by two adjacent point mutations in the Rp1 gene in a colony of C57BL/6J mice. Mice homozygous for the L66P mutation exhibited slow, progressive photoreceptor degeneration throughout their lifespan. Optical coherence tomography imaging found abnormal photoreceptor reflectivity at 1 month of age. Histology found shortening and disorganization of the photoreceptor inner and outer segments and progressive thinning of the outer nuclear layer. Electroretinogram a- and b-wave amplitudes were decreased with age. Western blot analysis found that the quantity and size of the mutated retinitis pigmentosa 1 (RP1) protein were normal. However, immunohistochemistry found that the mutant Rp1 protein partially mislocalized to the transition zone of the shortened axonemes. This mutation disrupted colocalization with cytoplasmic microtubules in vitro. In conclusion, the L66P mutation in the first doublecortin domain of the Rp1 gene impairs Rp1 protein localization and function, leading to abnormalities in photoreceptor outer segment structure and progressive photoreceptor degeneration. This is the first missense mutation in Rp1 shown to cause retinal degeneration. It provides a unique, slowly progressive photoreceptor degeneration model that mirrors the slow degeneration kinetics in most patients with retinitis pigmentosa.
Rahimi Darabad R, Suzuki T, Richards S, Jakobiec F, Zakka F, Barabino S, Sullivan D. Does estrogen deficiency cause lacrimal gland inflammation and aqueous-deficient dry eye in mice?. Exp Eye Res. 2014;127:153–60.

Researchers have proposed that estrogen deficiency will lead to a Sjögren's syndrome (SjS)-like lacrimal gland inflammation, aqueous tear deficiency and dry eye. The purpose of this study was to determine whether this proposal is correct. Lacrimal glands were obtained from adult, age-matched wild type (WT) and aromatase knockout (ArKO) mice, in which estrogen synthesis is completely eliminated. Tissues were also obtained from autoimmune MRL/Mp-lpr/lpr (MRL/lpr) mice as inflammation controls. Tear volumes in WT and ArKO mice were measured and glands were processed for molecular biological and histological evaluation. Our results demonstrate that estrogen absence does not lead to a SjS-like inflammation in lacrimal tissue or to an aqueous-deficient dry eye. There was no upregulation of genes associated with inflammatory pathways in lacrimal glands of male or female ArKO mice. Such inflammatory activity was prominent in autoimmune MRL/lpr tissues. We also found no evidence of inflammation in lacrimal gland tissue sections of estrogen-deficient mice, and tear volumes of ArKO males were actually increased as compared to those WT controls. Interestingly, our study did show that estrogen absence influences the expression of thousands of lacrimal gland genes, and that this impact is sex- and genotype-specific. Our findings demonstrate that estrogen absence is not a risk factor for the development of SjS-like lacrimal gland inflammation or for aqueous-deficient dry eye in mice.

Dartt DA, Masli S. Conjunctival epithelial and goblet cell function in chronic inflammation and ocular allergic inflammation.. Curr Opin Allergy Clin Immunol. 2014;14(5):464–70.

PURPOSE OF REVIEW: Although conjunctival goblet cells are a major cell type in ocular mucosa, their responses during ocular allergy are largely unexplored. This review summarizes the recent findings that provide key insights into the mechanisms by which their function and survival are altered during chronic inflammatory responses, including ocular allergy. RECENT FINDINGS: Conjunctiva represents a major component of the ocular mucosa that harbors specialized lymphoid tissue. Exposure of mucin-secreting goblet cells to allergic and inflammatory mediators released by the local innate and adaptive immune cells modulates proliferation, secretory function, and cell survival. Allergic mediators like histamine, leukotrienes, and prostaglandins directly stimulate goblet cell mucin secretion and consistently increase goblet cell proliferation. Goblet cell mucin secretion is also detectable in a murine model of allergic conjunctivitis. Additionally, primary goblet cell cultures allow evaluation of various inflammatory cytokines with respect to changes in goblet cell mucin secretion, proliferation, and apoptosis. These findings in combination with the preclinical mouse models help understand the goblet cell responses and their modulation during chronic inflammatory diseases, including ocular allergy. SUMMARY: Recent findings related to conjunctival goblet cells provide the basis for novel therapeutic approaches, involving modulation of goblet cell mucin production, to improve treatment of ocular allergies.

Jakobiec F, Rashid A, Lane K, Kazim M. Granulomatous dacryoadenitis in regional enteritis (crohn disease).. Am J Ophthalmol. 2014;158(4):838–844.e1.

PURPOSE: To evaluate the clinical and immunopathologic features of 2 patients with bilateral dacryoadenitis associated with regional enteritis. DESIGN: Retrospective, clinicopathologic study. METHODS: Clinical records, photographs, and imaging studies were reviewed and microscopic sections of lacrimal gland biopsy samples were critically re-evaluated. The microscopic slides were stained with hematoxylin and eosin, special stains for organisms, and a range of immunohistochemical biomarkers, including CD3, CD4, CD5, CD8, CD20, CD68, CD138, CD1a, and immunoglobulins Ig G, IgG4, and IgA. RESULTS: Both patients were young women with a well-established diagnosis of regional enteritis. Histopathologic examination of biopsy samples disclosed moderate intraparenchymal fibrosis and lymphoplasmacytic infiltrates without lymphoid follicles. Small to medium intraparenchymal, noncaseating granulomas lacking multinucleated giant cells and, in 1 patient, CD68-positive and CD1a-negative palisading granulomas in widened interlobular fibrous septa were detected. Vasculitis and IgG4 plasma cells were not observed. Additional immunohistochemical studies revealed that CD8 T lymphocytes (suppressor or cytotoxic subset) predominated over CD4-positive T lymphocytes (helper cells) surrounding the necrobiotic foci and were intermixed with the CD68-positive histiocytes in the absence of CD20 B lymphocytes. Special stains for organisms demonstrated negative results. CONCLUSIONS: Dacryoadenitis is the rarest form of ocular adnexal involvement in regional enteritis, which affects the orbit far more frequently than ulcerative colitis. It is a granulomatous process with the possibility of palisading necrobiotic foci. In contrast, ulcerative colitis causes an interstitial lymphocytic and nongranulomatous myositis. Sarcoidosis, Wegener granulomatosis, and pseudorheumatoid nodules must be ruled out. Treatment options entail a wide variety of agents with selection based on empirical considerations and tailored to the patient's symptoms.

Werdich X, Jakobiec F, Curtin H, Fay A. A clinical, radiologic, and immunopathologic study of five periorbital intraosseous cavernous vascular malformations.. Am J Ophthalmol. 2014;158(4):816–826.e1.

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).

Samsom M, Morrison S, Masala N, Sullivan B, Sullivan D, Sheardown H, Schmidt T. Characterization of full-length recombinant human Proteoglycan 4 as an ocular surface boundary lubricant. Exp Eye Res. 2014;127:14–9.
Proteoglycan 4 (PRG4, or lubricin) is a lubricating mucin-like glycoprotein recently discovered at the ocular surface, where it functions as a boundary lubricant and appears to play a protective role. Recent technological advances have enabled abundant expression of full-length recombinant human PRG4 (rhPRG4). The objectives of this study were to 1) biochemically characterize the gross structure and glycosylations of full-length rhPRG4, and 2) assess the ocular surface boundary lubricating ability of rhPRG4 at both human cornea-eyelid and human cornea-polydimethylsiloxane (PDMS) biointerfaces. rhPRG4 expressed by a Chinese hamster ovary cell line was characterized and compared to native bovine PRG4 by SDS-PAGE western blotting, and protein identity was assessed by tandem mass spectrometry (MS/MS). Human corneas were articulated against PDMS or human eyelids, at effective sliding velocities of 0.3-30 mm/s under physiological loads of ∼15 kPa, to assess and compare the ocular lubricating ability of rhPRG4 to PRG4. Samples were tested serially in PRG4, rhPRG4 (both 300 μg/ml), then saline. Western blotting indicated that rhPRG4 had immunoreactivity at the appropriate apparent molecular weight, and possessed O-linked glycosylation consistent with that of PRG4. rhPRG4 protein identity was confirmed by MS/MS. Both PRG4 and rhPRG4 significantly, and similarly, reduced friction compared to saline at both human cornea - PDMS and human cornea-eyelid biointerfaces. In conclusion, the rhPRG4 studied here demonstrated appropriate higher order structure, O-linked glycosylations, and ocular surface boundary lubricating. Purified rhPRG4 may have clinical utility as a topical treatment of dry eye disease or contact lens biomaterial coating to promote more comfortable wear.
Sandberg M, Pearce E, Harper S, Weigel-DiFranco C, Hart L, Rosner B, Berson E. The relationship of central foveal thickness to urinary iodine concentration in retinitis pigmentosa with or without cystoid macular edema.. JAMA Ophthalmol. 2014;132(10):1209–14.

IMPORTANCE: Current treatments for cystoid macular edema (CME) in retinitis pigmentosa (RP) are not always effective, may lead to adverse effects, and may not restore visual acuity. The present research lays the rationale for evaluating whether an iodine supplement could reduce CME in RP. OBJECTIVE: To determine whether central foveal thickness (CFT) in the presence of CME is related to dietary iodine intake inferred from urinary iodine concentration (UIC) in nonsmoking adults with RP. DESIGN, SETTING, AND PARTICIPANTS: We performed a cross-sectional observational study of 212 nonsmoking patients aged 18 to 69 years referred to our institution for RP with visual acuity of no worse than 20/200 in at least 1 eye. EXPOSURE: Retinitis pigmentosa with or without CME. MAIN OUTCOMES AND MEASURES: With the eye as the unit of analysis, the relationship of log CFT measured by optical coherence tomography to UIC measured from multiple spot samples and represented as a 3-level classification variable (<100, 100-199, and ≥200 µg/L), assigning greater weight to patients with more reliable UIC estimates. RESULTS: Analyses were limited to 199 patients after excluding 11 who failed to return urine samples for measuring UIC and 2 outliers for UIC. Of the 199 patients, 36.2% had CME in 1 or both eyes. Although log CFT was inversely related to UIC based on findings from all eyes (P = .02), regression of log CFT on UIC separately for eyes with and without CME showed a strong inverse significant relationship for the former group (P < .001) and no significant relationship for the latter group (P = .66) as tested. For the eyes with CME, CFT ranged from a geometric mean of 267 µm for a median UIC of less than 100 µg/L to a geometric mean of 172 µm for a median UIC of 200 µg/L or greater. In contrast, we found no significant association between CME prevalence and UIC based on the entire sample as tested (odds ratio, 1.01 [95% CI, 0.38-2.67]; P = .99). CONCLUSIONS AND RELEVANCE: A higher UIC in nonsmoking adults with RP was significantly associated with less central foveal swelling in eyes with CME. Additional study is required to determine whether an iodine supplement can limit or reduce the extent of CME in patients with RP.

Ratnapriya R, Zhan X, Fariss R, Branham K, Zipprer D, Chakarova C, Sergeev Y, Campos M, Othman M, Friedman J, Maminishkis A, Waseem N, Brooks M, Rajasimha H, Edwards A, Lotery A, Klein B, Truitt B, Li B, Schaumberg D, Morgan D, Morrison M, Souied E, Tsironi E, Grassmann F, Fishman G, Silvestri G, Scholl H, Kim I, Ramke J, Tuo J, Merriam J, Merriam J, Park KH, Olson L, Farrer L, Johnson M, Peachey N, Lathrop M, Baron R, Igo R, Klein R, Hagstrom S, Kamatani Y, Martin T, Jiang Y, Conley Y, Sahel JA, Zack D, Chan CC, Pericak-Vance M, Jacobson S, Gorin M, Klein M, Allikmets R, Iyengar S, Weber B, Haines J, Léveillard T, Deangelis M, Stambolian D, Weeks D, Bhattacharya S, Chew E, Heckenlively J, Abecasis G, Swaroop A. Rare and common variants in extracellular matrix gene Fibrillin 2 (FBN2) are associated with macular degeneration.. Hum Mol Genet. 2014;23(21):5827–37.

Neurodegenerative diseases affecting the macula constitute a major cause of incurable vision loss and exhibit considerable clinical and genetic heterogeneity, from early-onset monogenic disease to multifactorial late-onset age-related macular degeneration (AMD). As part of our continued efforts to define genetic causes of macular degeneration, we performed whole exome sequencing in four individuals of a two-generation family with autosomal dominant maculopathy and identified a rare variant p.Glu1144Lys in Fibrillin 2 (FBN2), a glycoprotein of the elastin-rich extracellular matrix (ECM). Sanger sequencing validated the segregation of this variant in the complete pedigree, including two additional affected and one unaffected individual. Sequencing of 192 maculopathy patients revealed additional rare variants, predicted to disrupt FBN2 function. We then undertook additional studies to explore the relationship of FBN2 to macular disease. We show that FBN2 localizes to Bruch's membrane and its expression appears to be reduced in aging and AMD eyes, prompting us to examine its relationship with AMD. We detect suggestive association of a common FBN2 non-synonymous variant, rs154001 (p.Val965Ile) with AMD in 10 337 cases and 11 174 controls (OR = 1.10; P-value = 3.79 × 10(-5)). Thus, it appears that rare and common variants in a single gene-FBN2-can contribute to Mendelian and complex forms of macular degeneration. Our studies provide genetic evidence for a key role of elastin microfibers and Bruch's membrane in maintaining blood-retina homeostasis and establish the importance of studying orphan diseases for understanding more common clinical phenotypes.

Cattaneo Z, Lega C, Gardelli C, Merabet L, Cela-Conde C, Nadal M. The role of prefrontal and parietal cortices in esthetic appreciation of representational and abstract art: a TMS study. Neuroimage. 2014;99:443–50.
To explain the biological foundations of art appreciation is to explain one of our species' distinctive traits. Previous neuroimaging and electrophysiological studies have pointed to the prefrontal and the parietal cortex as two critical regions mediating esthetic appreciation of visual art. In this study, we applied transcranial magnetic stimulation (TMS) over the left prefrontal cortex and the right posterior parietal cortex while participants were evaluating whether they liked, and by how much, a particular painting. By depolarizing cell membranes in the targeted regions, TMS transiently interferes with the activity of specific cortical areas, which allows clarifying their role in a given task. Our results show that both regions play a fundamental role in mediating esthetic appreciation. Critically though, the effects of TMS varied depending on the type of art considered (i.e. representational vs. abstract) and on participants' a-priori inclination toward one or the other.