Peptidoglycan (PGN) recognition proteins (PGLYRPs) are innate immune
molecules that recognise bacterial cell wall PGN, and participate in several
inflammatory diseases such as arthritis. We sought to elucidate the
contribution of PGLYRPs in murine uveitis (intraocular inflammatory disease)
elicited by PGN, and the extent to which systemically administered PGN
alters uveitis compared with arthritis versus locally triggered ocular
Mice deficient for PGLYRP-2, PGLYRP-3 or PGLYRP-4 were administered
PGN by an intraperitoneal or intraocular injection. Arthritis was assessed
by near-infrared imaging and histopathology, while uveitis was measured by
intravital videomicroscopy and histopathology.
Systemic PGN exposure predisposed to arthritis through a PGLYRP-2
dependent mechanism. By contrast, systemic PGN exposure did not predispose
to uveitis, and PGLYRP-2 deficiency had no impact on the development the
uveitis. When PGN was administered locally, a robust uveitis ensued, which
occurred independently of PGLYRP-2. Regardless of whether PGN was
administered systemically or locally, neither PGLYRP-3 nor PGLYRP-4
deficiency significantly altered ocular inflammation compared with wild-type
Our findings highlight the complexity of PGLYRPs and how PGLYRP-2 may
use different molecular pathways in the joints versus eyes. Collectively,
our results support a non-essential or redundant role for PGLYRPs-2, -3, -4
To evaluate the utility of in vivo imaging of rabbit model of choroidal melanoma utilizing high-frequency contrast-enhanced ultrasound (HF-CE-US) with 2-or 3-dimensional modes, and to correlate the sonographic findings with histopathologic characteristics.
Five New Zealand white rabbits which were immunosuppressed with daily cyclosporin A were inoculated into their right eyes with aliquots of 1.5×106 / 50 µL of 92.1 human uveal melanoma cells cultured in RPMI. At week 4, the tumor-bearing eyes were imaged using high-frequency ultrasound with microbubble contrast agent to determine the 2-dimensional tumor size and relative blood volume and by 3-dimensional mode to determine tumor volume. Histologic tumor burden was quantified in enucleated eyes by ImageJ software, and microvascular density (MVD) was determined by counting vascular channels in PAS without hematoxylin sections.
Utilizing HF-CE-US, melanomas were visualized as relatively hyperechoic regions in the images. The correlation coefficients of sonographic size or volume compared with histologic area were 0.72 and 0.70, respectively. The sonographic tumor relative blood volume correlated with the histologic tumor vascularity (R2=0.92, P=0.04)
There is a positive correlation between in vivo sonographic tumor volume/size and histologic tumor size in our rabbit choroidal melanoma model. HF-CE-US corresponds to microvascular density and blood volume.
To investigate the choroidal vascular regulation in age related macular degeneration (AMD) we compared the regulatory responses induced by isometric exercise in control subjects and patients with AMD.
Seventeen eyes of 17 patients with dry AMD in the study eye and 19 eyes of 19 controls were included in this study. Both groups were well matched in regards to age, race and gender. Brachial artery blood pressure determinations and laser Doppler flowmetry (Oculix) measurements of relative foveolar choroidal blood velocity, volume, and flow were obtained in the study eye of each subject during 30 seconds of baseline, and then, during 3 minutes of isometric exercise consisting of squeezing a hand grip in each hand. Similar measurements were then also obtained during the two minutes following the cessation of exercise. Using non-paired, two-tailed t-test, changes in circulatory parameters during exercise and following the end of exercise were compared between AMD patients and control subjects. The slope for the relationship between circulatory changes and perfusion pressure changes was calculated and compared between AMD patients and controls using linear regression analysis. Analysis of data was performed in a masked fashion. Circulatory measurements are shown in arbitrary units (AU).
There were no statistically significant differences between the changes in ChBVel, ChBVol and ChBFlow observed in control subjects and AMD patients during the isometric exercise phase and after exercise.
Our results suggest that the response of the choroidal circulation to this type of isometric exercise resulting in a moderate increase in blood pressure does not seem to be affected by AMD.
Isometric exercises; choroidal blood flow; Age-Related Macular Degeneration (AMD)
To investigate the risk factors for myopia, including near work and outdoor activity, in Singapore Chinese preschool children.
A cross-sectional study, with disproportionate random sampling by 6-month age groups, of 3009 Singapore Chinese children aged 6–72 months was performed. Information on family history, near work and outdoor activity was obtained. Spherical equivalent refraction (SEA) was assessed.
Children with two myopic parents were more likely to be myopic (adjusted OR=1.91; 95% CI 1.38 to 2.63) and to have a more myopic SER (regression coefficient=−0.35; 95% CI −0.47 to −0.22) than children without myopic parents. For each 1 cm taller height, the SER was more myopic by 0.01 dioptres. Neither near work nor outdoor activity was associated with preschool myopia.
A family history of myopia was the strongest factor associated with preschool myopia. In contrast, neither near work nor outdoor activity was found to be associated with early myopia. These data suggest that genetic factors may play a more substantial role in the development of early-onset myopia than key environmental factors.
It has been postulated that eye movement disorders in chronic progressive external ophthalmoplegia (CPEO) have a neurological as well as a myopathic component to them.
To investigate whether there is a supranuclear component to eye movement disorders in CPEO using eye movement recordings.
Saccade and smooth pursuit (SP) characteristics together with vestibulo-ocular reflex (VOR) gain and VOR suppression (VORS) gain in 18 patients with CPEO and 34 normal patients were measured using Eyelink II video-oculography.
The asymptotic values of the peak velocity main sequence curves were reduced in the CPEO group compared to those of normal patients, with a mean of 161°/s (95% CI 126°/s to 197°/s) compared with 453°/s (95% CI 430 to 475°/s), respectively. Saccadic latency was longer in CPEO (263 ms; 95% CI 250 to 278), compared to controls (185 ms; 95% CI 181 to 189). Smooth pursuit and VOR gains were impaired in CPEO, although this could be explained by non-supranuclear causes. VORS gain was identical in the two groups.
This study does not support a supranuclear component to the ophthalmoplegia of CPEO, although the increased latencies observed may warrant further investigation.
A 53-year-old man presented with an acute bilateral posterior uveitis with extensive necrotizing retinochoroiditis but without chorioretinal scarring. A thorough workup did not reveal any underlying disease. The possibilities of atypical ocular toxoplasmosis as well as herpetic retinal necrosis were considered and specific therapy instituted, with little improvement. The patient died within two months as result of an undifferentiated squamous cell carcinoma.
Histopathological examination, immunohistochemistry and multi-locus polymerase chain reaction confirmed T. gondii infection of the retina
Macroscopic examination of enucleated globe showed extensive retinal necrosis and vitreous detachment. Histological examination of retinal tissue identified numerous round–to-elliptical toxoplasmic cysts within the retina, with retinal necrosis and minimal choroidal inflammation. Immunohistochemical analyses confirmed the cysts were due to Toxoplasma gondii. DNA extracted from formalin-fixed, paraffin-embedded tissue sections was subjected to multi-locus PCR analysis at the following typing loci: SAG1, SAG2, SAG3, SAG4, B1, NTS2, GRA6, and GRA7. DNA sequencing of positive PCR products at the NTS2, SAG1, and GRA7 loci confirmed the presence of a non-archetypal strain of T. gondii infecting the eye of the patient experiencing a severe, atypical ocular toxoplasmosis
A highly divergent, non-archetypal strain of Toxoplasma gondii was responsible for causing a severe, atypical bilateral retinochoroiditis in a patient from Brazil.
Microbiology; Pathology; Genetics; Infection; Diagnostic tests/Investigation
We examined whether retinitis pigmentosa (RP) subjects' worse-than-usual vision measures were related to episodic changes in psychosocial factors and/or general health.
In a prospective, cohort study, 37 RP subjects self-administered personal computer (PC)-based visual acuity (VA), contrast sensitivity (CS) and visual field (VF) tests at home twice a week, for 16 sessions in 2–3 months. Subjects rated their general health prior to each vision test session, and completed the Perceived Stress Scale, Positive and Negative Affect Schedules, and Epworth and Stanford Sleepiness Scales immediately after each session.
Nine subjects with reduced mean VA >0.5 log minimal angle of resolution (logMAR) on average had statistically significant 26% more sessions with measured deviations ≥0.1 logMAR from their mean (95% CI 20% to 32%; p<0.001), which were not significantly related to changes in psychosocial factors or general health. Measured deviations ≥0.1 logCS from mean CS were not statistically significantly related to any measured factors. We found a statistically significant increased frequency of sessions with ≥20% VF reduction from the mean (p<0.001) as mean log VF area was reduced. Subjects reporting reduced general health during a session had a statistically significant over twofold greater odds of having a VF reduction from the mean beyond 1 SD (95% CI 1.26 to 5.00; p=0.009).
Measured episodic VF reductions were more common in advanced RP and related to decreased general health at a session, which should be considered during clinical examinations and trials when determining true changes in vision. We did not find evidence that fluctuations in psychosocial factors were significantly correlated with vision reductions across subjects.
Bisphosphonates have been shown to induce ocular inflammatory diseases such as uveitis and scleritis, while being protective against angiogenic diseases like neovascular age-related macular degeneration (AMD). Therefore, we studied the effects of bisphosphonates on primary culture of human fetal retinal pigment epithelium (hRPE), a cell type known to secrete both inflammatory and angiogenic factors. Alendronate and etidronate were selected for this experiment as they are members of the two structurally different classes of bisphosphonates.
Primary cultures of hRPE were serum-starved for 24 h and then treated for 24 h with alendronate (0.0001, 0.1, 100 μM) or etidronate (0.01, 1 μM). Cell viability was measured using the MTT assay. Investigation of secreted cytokines induced by bisphosphonates was performed using a human cytokine 29-Plex Panel (Bio-Plex) array and the results were analysed with an analysis of variance (ANOVA).
Etidronate, at the lower concentration, significantly increased the expression of interleukin (IL)-6 (p=0.03) and IL-8 (p=0.04). At the higher concentration, etidronate significantly decreased the expression of granulocyte macrophage colony-stimulating factor (p=0.02) and basic fibroblast growth factor (bFGF) (p=0.02). Alendronate, at the highest concentration, significantly increased the expression of IL-8 (p=0.02) and decreased the expression of eotaxin (p=0.02). Alendronate also significantly decreased the expression of bFGF at all concentrations (p<0.05) and demonstrated a trend towards decreasing vascular endothelial growth factor expression at low concentration.
Alendronate and etidronate display dose dependent effects in hRPE cells. Alendronate and etidronate administration resulted in concentration dependent elevations in inflammatory cytokines. Furthermore, alendronate and etidronate administration resulted in reduced expression of a number of angiogenic factors. These findings may explain the increased incidence of ocular inflammation as well as the therapeutic effect on neovascular AMD which have been described with bisphosphonates.
PMID: 23766431 CAMSID: cams4155
To examine associations between retinal thickness and rod-mediated dark adaptation in older adults with non-exudative age-related maculopathy (ARM) or normal macular health.
A cross-sectional study was conducted with 74 adults ≥ 50 years old from the comprehensive ophthalmology and retina services of an academic eye center. ARM presence and disease severity in the enrollment eye was defined by the masked grading of stereofundus photos using the Clinical Age-Related Maculopathy (CARMS) grading system. High-definition, spectral-domain optical coherence tomography was used to estimate retinal thickness in a grid of regions in the macula. Rod-mediated dark adaptation, recovery of light sensitivity after a photo-bleach, was measured over a 20-minute period for a 500 nm target presented at 5° on the inferior vertical meridian. Main outcomes of interest were retinal thickness in the macula (μm) and parameters of rod-mediated dark adaptation (second slope, third slope, average sensitivity, final sensitivity).
In non-exudative disease retinal thickness was decreased in greater disease severity; thinner retina was associated with reductions in average and final rod-mediated sensitivity even after adjustment for age and visual acuity.
Impairment in rod-mediated dark adaptation in non-exudative ARM is associated with macular thinning.
age-related maculopathy; dark adaptation; rod photoreceptors; optical coherence tomography
To compare detection of retinal nerve fiber layer (RNFL) changes using GDx Guided Progression Analysis (GPA) fast mode (which assumes fixed variability of a reference population) and extended mode (which measures individual variability) and to determine how they compare to photography and visual field based conventional methods for identifying glaucoma progression.
172 eyes from 117 participants in the Diagnostic Innovations in Glaucoma Study (DIGS) (12 healthy, 108 glaucoma suspect and 52 glaucoma eyes) with ≥4 GDx VCC visits and ≥3 good quality GDx VCC scans at each visit were included. Results: Agreement between the GDx GPA fast mode and GDx GPA extended mode was limited. The GDx fast mode and extended mode detected 15 and 18 eyes, respectively as “likely progression” but only 7 of them agreed. The conventional reference standard (stereophotograph based optic disc and/or visual field progression) identified 9 eyes as progressing of which 2 eyes were also identified by the GDx fast and 3 eyes by the extended mode. In the GDx fast mode, we found that the progression detection varies depending on which 2 scans are included in the baseline and follow-up images. Conclusion: There was limited agreement between the GDx fast mode and the GDx extended mode for progression detection, and between different scans included in the GDx fast mode progression analysis. Longer follow-up is needed to determine the proportion of eyes classified as “likely progression” by the GDx analysis that are early change and the proportion that are false positive results.
glaucoma; imaging; diagnostic tests/investigation
To examine near vision spectacle retention and use, and changes in self-reported and performance-based near vision, 2 months after the provision of near vision spectacles.
We conducted a 2-month follow-up of a population-based cohort of persons in rural Tanzania with near vision impairment who had received spectacles. Previously, residents age ≥40 years were examined for distance and near vision acuity. Those with presbyopia and hyperopia (‘functional presbyopia’) were given near vision spectacles. At baseline, subjects were asked to thread a needle; they were also asked questions on the perception of their near vision, ability to be independent and general health. At 2 months, subjects were again queried. Questions on the perceived affordability of replacement spectacles were also asked.
Of the 866 people provided with spectacles, 89% were seen at 2 months. Ninety-two per cent were still using the spectacles. Users were more likely to have any education (51.8%) than non-users (28.3%) (p<0.001). Only 31% had successfully threaded a needle at baseline, increasing to 91% at follow-up (p<0.001). Spectacle-users showed a significant improvement in satisfaction with near vision and ability to be independent, but no change in perception of general health, from baseline to follow-up. Men were more likely than women to be able to afford spectacles and to know where to get them.
Our cohort maintained their spectacles and reported tangible improvements associated with their use. The value of simple reading spectacles for those with near vision impairment suggests that a greater emphasis on near vision is needed in the Vision 2020 agenda.
Lithium previously has been shown to reduce both endoplasmic reticulum (ER) and oxidative stress in other in vitro and in vivo model systems. We investigated lithium’s effects on cultured corneal endothelial cells (CECs) exposed to these types of stress and in a mouse model of Fuchs endothelial corneal dystrophy (FECD).
Viability of cultured bovine CECs was determined by CellTiter-Glo. 2-month-old Col8a2Q455K/Q455K mutant (Q455K) and C57/Bl6 wild type animals were divided into two groups of 15 mice. Group I received 0.2% lithium carbonate-containing chow and Group II received control chow for 7 months. Confocal microscopy, transmission electron microscopy, real-time PCR (RT-PCR) and western blot were performed.
Pretreatment with lithium increased viability of cultured CECs after H2O2 and thapsigargin exposure compared with untreated controls (p<0.05). In vivo analysis of mouse corneal endothelium showed the following: endothelial cell density of lithium treated Q455K was higher than for untreated Q455K (p<0.01). transmission electron microscopy of lithium treated Q455K showed normal endothelium with enlarged autophagosomes, but untreated Q455K showed dilated ER and guttae. Compared with untreated Q455K endothelium, lithium treated Q455K showed significant upregulation of P62, Tmem74, Tm9sf1 and Tmem 166 by RT-PCR and of Atg5-12 conjugate by western blotting indicating that lithium treatment increased autophagy. Although RT-PCR unexpectedly showed increased levels of lithium response genes, caspase 12, Gsk3β, Arrβ2 and Impa1, western blotting showed the expected downregulation of Arrβ2 and Impa1 proteins in response to lithium treatment.
Lithium increases cultured CEC survival against ER and oxidative stress. Increased autophagy in lithium treated endothelium in a mouse model of FECD suggests autophagy may contribute to increased endothelial cell survival.
This paper will compare the visual outcomes of two different penetrating keratoplasty (PKP) techniques in patients with keratoconus. It is a retrospective comparative surgical case series of 116 keratoconus patients (137 eyes) who had PKP at the Cornea Eye Institute, Beverly Hills, California, USA.
56 keratoconus patients (66 eyes) underwent femtosecond laser-enabled keratoplasty (FLEK) with a zig-zag incision configuration. Their visual parameters were compared with those of 60 patients (71 eyes) who had traditional blade mechanical trephination PKP. The range of follow-up was between 3 and 6 months. The main outcome measures included uncorrected visual acuity and best spectacle-corrected visual acuity (BSCVA), manifest refractive spherical equivalent and topographically determined astigmatism.
BSCVA was significantly better as early as 3 months postoperatively (p=0.001) in the FLEK group. Visual recovery to 20/40 after 3 months was significantly better in the FLEK group (p<0.001). Topographic astigmatism was lower in the FLEK group, but the difference between the two groups reached significance only at 3 months of follow-up (p=0.001). Postoperative complications noted were not different between the two groups.
Faster visual recovery and better long-term outcomes were observed in keratoconus patients who had FLEK compared with those who had the mechanical PKP procedure with 6 months of postoperative follow-up.
Glaucoma; confocal scanning laser ophthalmoscopy; screening; stereo photographs; intraobserver variability
Alterations in intraocular oxygen levels are important contributors to, or indications of ocular disease. Polarographic electrodes and fiberoptic sensors (optodes) have been used to measure oxygen and to map the distribution of oxygen in animal models and in human eyes. A recent study reported the use of a commercial electrode to compare oxygen distribution in the vitreous of patients undergoing vitrectomy related to central retinal vein occlusion, macular hole or preretinal membrane. The results of this study were at variance with previous measures of oxygen distribution in the human vitreous using polarographic or optical sensors. To resolve this discrepancy, the present study compared measurements made in vitro or in animal eyes, using the electrode employed in the previous study or a fiberoptic sensor of different design.
Comparative in vitro and in vivo measurements.
In vitro, the two devices reported similar levels of oxygen, although the electrode consistently detected levels above the calculated values. In rabbit eyes, the electrode had a slow response time and was unable to detect oxygen gradients that were readily measured by the smaller optode. When the electrode was inserted into an eye of similar size to the human eye, the reference thermistor measured the temperature outside the eye, not in the vitreous.
The design of the electrode used in the previous study makes it unsuitable for measurements of oxygen distribution in the eye.
To evaluate the glaucoma discriminating ability of macular retinal layers as measured by spectral-domain optical coherence tomography (SD-OCT).
Healthy, glaucoma suspect and glaucomatous subjects had a comprehensive ocular examination, visual field testing and SD-OCT imaging (Cirrus HD-OCT; Carl Zeiss Meditec, Dublin, CA) in the macular and optic nerve head regions. OCT macular scans were segmented into macular nerve fiber layer (mNFL), ganglion cell layer with inner plexiform layer (GCIP), ganglion cell complex (GCC) (composed of mNFL and GCIP), outer retinal complex (ORC) and total retina (TR). Glaucoma discriminating ability was assessed using the area under the receiver operator characteristic curve (AUC) for all macular parameters and mean circumpapillary (cp) RNFL. Glaucoma suspects and glaucoma subjects were grouped together for the calculation of AUCs.
Analysis was performed on 51 healthy, 49 glaucoma suspect and 63 glaucomatous eyes. The median visual field MD was −2.21dB (interquartile range (IQR): −6.92 to −0.35) for the glaucoma group, −0.32dB (IQR: −1.22 to 0.73) for the suspect group and −0.18dB (IQR: −0.92 to 0.71) for the healthy group. Highest age adjusted AUCs for discriminating between healthy and glaucomatous eyes were found for average GCC and GCIP (AUC=0.901 and 0.900, respectively), and their sectoral measurements: infero-temporal (0.922 and 0.913), inferior (0.904 and 0.912) and supero-temporal (0.910 and 0.897). These values were similar to the discriminating ability of the mean cpRNFL (AUC=0.913). Comparison of these AUCs did not yield any statistically significant difference (all p>0.05). Similar discrimination performance but with slight reduction in AUCs was achieved for comparison between healthy and the combination of glaucoma and glaucoma suspect eyes.
SD-OCT GCIP and GCC measurements showed similar glaucoma diagnostic ability and was comparable with that of cpRNFL.