Mapping diurnal variations in choroidal sublayer perfusion in patients with idiopathic epiretinal membrane: an optical coherence tomography angiography study

Background

Optical coherence tomography angiography (OCTA) is a non-invasive tool for imaging and quantifying the choroidal vasculature and perfusion state. In this index study, OCTA was used to investigate diurnal changes in choroidal sublayer perfusion in eyes with idiopathic epiretinal membrane (ERM) and to identify impacting factors.

Methods

A prospective study was conducted on volunteers with symptomatic ERM, each of whom underwent repeated measurements of subfoveal choroidal thickness (SFCT) using enhanced-depth imaging optical coherence tomography and perfusion of choroidal vascular sublayers using OCTA at 7 a.m., 12 p.m., 4 p.m., and 8 p.m. Possible interactions between diurnal variations and other factors, such as gender and age, were evaluated.

Results

A total of 21 eyes of 21 participants (mean age 72.43 ± 7.06 years) were analysed. A significant pattern of diurnal variation was observed for SFCT (p = 0.008) as well as perfusion of Haller's layer (HLP, p = 0.001). SFCT and HLP both demonstrated a quadratic relation to time of the day, decreasing from morning to afternoon, before increasing again in the evening. No significant differences with regard to gender or age were detectable.

Conclusion

OCTA-based analysis of choroidal sublayer perfusion demonstrated significant diurnal variations in patients with symptomatic ERM, which are quite different from changes reported in healthy eyes. Therefore, it is important to account for time of day, when comparing longitudinal OCTA data.

Subfoveal Choroidal Thickness as a Potential Predictor of Clinical Response to Stereotactic Radiotherapy for Neovascular Age-Related Macular Degeneration

BACKGROUND AND OBJECTIVE

Stereotactic radiotherapy (SRT) is a new adjuvant treatment modality that has been shown to reduce the need for repetitive intravitreal injections (IVIs) in patients with neovascular age-related macular degeneration (nAMD). The authors aimed to determine baseline predictors of clinical response to SRT.

PATIENTS AND METHODS

This was a retrospective, observational case series of patients with nAMD who underwent SRT and subsequently had at least 12 months of complete follow-up. After SRT and one mandatory IVI, patients were examined every 4 weeks and received further treatment on a pro re nata basis. Examination included enhanced depth imaging spectral-domain optical coherence tomography (SD-OCT) to measure subfoveal choroidal thickness (SFCT) and central macular thickness (CMT). Patients' data were retrieved from medical records and included demographics, disease duration, lesion size, best-corrected visual acuity (BCVA), previous number of IVIs, and type of drug applied.

RESULTS

A total of 35 eyes of 35 patients (76.23 years ± 7.05 years) were included, and 21 eyes (60%) responded well to SRT. The annual injection rate decreased from 6.86 before SRT to 3.46 afterward, whereas BCVA improved from 0.49 logMAR at baseline to 0.37 logMAR at final follow-up. From a morphologic point of view, CMT and SFCT decreased by 71 μm and 37 μm, respectively, at 12-month follow-up compared to baseline. Of all investigated parameters, only SFCT proved to be significant, as a higher baseline SFCT was found to be a strong negative predictor for the number of IVIs needed after SRT (regression coefficient: -0.678; P < .001).

CONCLUSIONS

Baseline SFCT may help predict which patients with nAMD will respond more favorably to SRT. The authors found eyes with a thicker baseline SFCT needed fewer IVIs after SRT. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:320-328.].

Synthesis, NMR Characterisation, X–ray Crystal Structure and Solution Studies of Ni(II) Complexes of a Pyridine Containing Self–assembling System

X-ray analysis of Ni(II) complexes of the self-assembling system LH2, [pyda.H2][pydc] (pydc.H2 = 2,6-pyridinedicarboxylic acid and pyda = 2,6-pyridinediamine), indicated that two six-coordinated anionic [pyda.H]2[Ni(pydc)2].H2O (I) and neutral [Ni(pydc.H)2].3H2O (II) complexes are formed at different temperature conditions in water; in agreement with the results obtained from potentiometric pH titrations in the pH range 3.5–5.5.

Subfoveal choriocapillaris, Sattler's and Haller's layer thickness predict clinical response to stereotactic radiotherapy in neovascular age-related macular degeneration patients

Purpose

To evaluate the significance of choroidal substructure analysis in predicting the clinical response to adjuvant stereotactic radiotherapy (SRT) in neovascular age-related macular degeneration (nAMD) patients.

Methods

Patients with nAMD, who underwent SRT (baseline) in addition to common intravitreal injections (IVIs) and subsequently had at least 12 months of complete follow-up, were enrolled. In a post hoc analysis, optical coherence tomography (OCT) data were reviewed, and subfoveal choroidal thickness (CT) as well as the thickness of choroidal substructures, such as choriocapillaris (CC), Sattler's layer (SL), and Haller's layer (HL), was measured to determine if these influenced SRT efficacy.

Results

A total of 35 eyes of 35 patients were included. While each of the 4 choroidal metrics significantly forecasts the clinical response to SRT, combining them all together produced the most reliable prediction model.

Conclusion

In terms of clinical response to SRT in nAMD patients, choroidal substructure analysis does improve the quality of the prediction model when combined with subfoveal CT.

Impact of correct anatomical slab segmentation on foveal avascular zone measurements by optical coherence tomography angiography in healthy adults

Purpose

To evaluate the impact of correct anatomical slab segmentation on foveal avascular zone (FAZ) dimensions in the superficial capillary plexus (SCP) and deep capillary plexus (DCP) using optical coherence tomography angiography (OCTA).

Methods

Participants with healthy retinas were recruited, and 5 × 5 mm OCTA images were acquired using the Canon HS-100 Angio eXpert module. FAZ size was measured in automatically (AS, manufacturer-based) and manually (MS, anatomical-based) segmented OCTA slabs by two experienced graders. FAZ dimensions, inter-rater agreement, and correlation to demographic and retinal parameters were evaluated.

Results

A total of 38 eyes from 20 healthy adult subjects were included in this cross-sectional study. While in AS slabs, the FAZ in the SCP was smaller than in the DCP, in MS images, it was the opposite. MS had a relevant impact on inter-rater agreement of FAZ measurements in the SCP. The FAZ area in both plexus correlated inversely with the central retinal thickness (CRT), irrespective of the segmentation applied. Furthermore, an enlargement of FAZ size in the DCP with increasing age was found. Finally, the FAZ in female participants was significantly larger than in their male counterparts, regardless of the evaluated plexus and chosen segmentation.

Conclusions

Correct anatomical slab segmentation has a significant impact on FAZ size measurements. Not adjusting the segmentation boundaries represents a significant source of error for measuring FAZ area and confounds comparisons across studies as well as OCTA devices.

ApoA-I Mimetic Peptide 4F Reduces Age-Related Lipid Deposition in Murine Bruch's Membrane and Causes Its Structural Remodeling

PURPOSE

Accumulation of lipoprotein-derived lipids including esterified and unesterified cholesterol in Bruch's membrane of human eyes is a major age-related change involved in initiating and sustaining soft drusen in age-related macular degeneration (AMD). The apolipoprotein (apo) A-I mimetic peptide 4F is a small anti-inflammatory and anti-atherogenic agent, and potent modifier of plasma membranes. We evaluated the effect of intravitreally-injected 4F on murine Bruch's membrane.

METHODS

We tested single intravitreal injections of 4F doses (0.6 µg, 1.2 µg, 2.4 µg, and placebo scrambled peptide) in ApoE^null mice ≥10 months of age. After 30 days, mice were euthanized. Eyes were processed for either direct immunofluorescence detection of esterified cholesterol (EC) in Bruch's membrane whole mounts via a perfringolysin O-based marker linked to green fluorescent protein or by transmission electron microscopic visualization of Bruch's membrane integrity. Fluorescein isothiocyanate-conjugated 4F was traced after injection.

RESULTS

All injected eyes showed a dose-dependent reduction of Bruch's membrane EC with a concomitant ultrastructural improvement compared to placebo treated eyes. At a 2.4 µg dose of 4F, EC was reduced on average by ~60% and Bruch's membrane returned to a regular pentalaminar structure and thickness. Tracer studies confirmed that injected 4F reached intraocular targets.

CONCLUSION

We demonstrated a highly effective pharmacological reduction of EC and restoration of Bruch's membrane ultrastructure. The apoA-I mimetic peptide 4F is a novel way to treat a critical AMD disease process and thus represents a new candidate for treating the underlying cause of AMD.

Changes in Peripapillary Nerve Fiber Layer Thickness after Adjuvant Stereotactic Radiotherapy in Patients with Neovascular Age-Related Macular Degeneration

PURPOSE

To evaluate the effect of stereotactic radiotherapy (SRT) in conjunction with intravitreal injections (IVI) of anti-vascular endothelial growth factor (anti-VEGF) drugs on peripapillary retinal nerve fiber layer (pRNFL) thickness in patients with neovascular age-related macular degeneration (nAMD).

METHODS

This was a retrospective, observational case series of patients with nAMD, who underwent SRT and subsequently had at least 12 months of complete follow-up. After SRT and one mandatory IVI, patients were examined monthly and received further treatment on a pro re nata basis. Examination included spectral-domain optical coherence tomography of the optic disc to measure pRNFL thickness. Patients' data were retrieved from medical records including demographics, disease duration, best-corrected visual acuity, previous number of intravitreal injections, and the type of drug applied.

RESULTS

A total of 35 eyes of 35 patients (76.23 ± 7.05 years) were included. The mean duration of nAMD at time of irradiation was 34.57 ± 16.96 months. During that time, patients received a mean total number of 15.83 ± 6.29 intravitreal injections, 6.86 ± 1.57 within the last 12 months before SRT. After SRT, on average 3.46 ± 2.09 injections were administered over 12 months, resulting in a mean total number of 19.29 ± 6.92 injections at final follow-up. The mean global pRNFL thickness was 97.23 ± 12.55 µm at time of irradiation, 95.54 ± 11.07 µm at 6 month (P = 0.299), and 95.29 ± 12.07 µm at 12 month (P = 0.373) follow-up.

CONCLUSION

SRT in conjunction with anti-VEGF injections did not lead to any significant change in pRNFL thickness over 12 months in patients with nAMD. However, long-term results are not yet available. Therefore, prospective studies with longer follow-up are needed to corroborate these findings.

[Patient-Reported Treatment Satisfaction with Stereotactic Radiotherapy in Neovascular Age-Related Macular Degeneration]

BACKGROUND

Stereotactic radiotherapy (SRT) in conjunction with the common intravitreal injections (IVI) is a new adjuvant approach in neovascular age-related macular degeneration (AMD) patients. The aim of our study was to investigate factors influencing patient satisfaction one year after SRT.

METHODS

A questionnaire was administered to 35 AMD patients who had consecutively undergone SRT using the IRay^®-device at the Department of Ophthalmology, University of Lübeck. In addition to descriptive statistics, responses were evaluated by correlation analysis. Moreover, subgroup analyses were performed, using a classification of IVI responders (annual injection rate after SRT ≤ 3), visual acuity (VA) responders (VA improvement ≥ 0.2 logMAR) and double responders (annual injection rate after SRT ≤ 3 as well as VA improvement ≥ 0.2 logMAR).

RESULTS

The response rate was 86%. With respect to their treatment expectations, twice as many patients hoped to receive less injections instead of a better vision. Those hoping for less injections were significantly more satisfied with their clinical outcome. In addition, IVI-responders were significantly more satisfied than IVI-non-responders, while VA-responders were not, compared to VA-non-responders.

CONCLUSIONS

Patient satisfaction seems to depend on patients' comprehension of how SRT affects their disease and what kinds of expectations were set. It is of utmost importance to provide the patients with adequate and comprehensible education and to define realistic goals prior to SRT.

The effect of anakinra on retinal function in isolated perfused vertebrate retina

Purpose

Blockage of the interleukin 1 (IL-1) signaling pathway has been proposed for treatment of inflammatory disorders like those affecting the retina and its adjacent tissue. Herein, we evaluated one of those inhibitory drugs, anakinra (Kineret^®), based on its safety profile with emphasis on retinal function from an electrophysiological point of view.

Methods

Bovine retina preparations were perfused with two different concentrations of anakinra (1 mg/ml and 2 mg/ml). An electroretinogram (ERG) was recorded and b-wave recovery assessed.

Results

Exposure to anakinra at a concentration of 1 mg/ml did not decrease the b-wave amplitude, whereas 2 mg/ml resulted in a significant reduction.

Conclusions

Based on these preliminary results, anakinra at a dose as low as 1 mg/ml could be regarded as safe for retinal function. However, dosages of 2 mg/ml and more do have toxic electrophysiological effects, at least for the short-term.

Stereotactic radiotherapy in neovascular age-related macular degeneration: Real-life efficacy and morphological evaluation of the outer retina-choroid complex

Stereotactic radiotherapy (SRT) is a new approach to treat neovascular age-related macular degeneration (nAMD). The INTREPID trial suggested that SRT could reduce the frequency of regular intravitreal injections (IVIs) with antivascular endothelial growth factor drugs, which are necessary to control disease activity. However, the efficacy of SRT in nAMD and resulting morphological changes have not been validated under real-life circumstances, an issue, which we would like to address in this retrospective analysis.Patients who met the INTREPID criteria for best responders were eligible for SRT. A total of 32 eyes of 32 patients were treated. Thereafter, patients were examined monthly for 12 months and received pro re nata IVI of aflibercept or ranibizumab. Outcome measures were: mean number of injections, best-corrected visual acuity, and morphological changes of the outer retina-choroid complex as well as patient safety.Mean number of IVI decreased by almost 50% during the 12 months after SRT compared to the year before, whereas visual acuity increased by one line (logMAR). Morphological evaluation showed that most changes affect outer retinal layers.Stereotactic radiotherapy significantly reduced IVI retreatment in nAMD patients under real-life circumstances. Therefore, SRT might be the first step to stop visual loss as a result of IVI undertreatment, which is a major risk.

Introducing MARCo: Histoserological Findings of a Multi-Organic Paraneoplastic Syndrome in Cutaneous Melanoma Patients

Introduction

Cutaneous melanoma (CM) is an aggressive skin cancer entity, causing most skin cancer-related deaths. Autoimmune disorders have been described as potential paraneoplastic complications. The purpose of this study was to elucidate the possibility of a combinatory paraneoplastic affection of the retina and cochlea in patients with CM.

Methods

Sera samples from CM patients were used for indirect immunofluorescence on histological retinal and cochlear sections. Furthermore, the serum specimen of a patient with symptomatic affection of both organs was analyzed by multiplex ELISA (enzyme-linked immunosorbent assay) for various cytokines including CD163 (cluster of differentiation 163).

Results

Eleven patients were diagnosed with CM. Autoantibodies against structures of the inner ear were confirmed in all patients who were tested positive for antiretinal antibodies as well. CD163 was significantly elevated in the double-symptomatic patient, who developed metastatic disease.

Conclusion

Paraneoplastic disease of CM can affect more than one organ and this affect may be correlated with the individual prognosis. Therefore, a thorough anamnesis is needed to avoid missing potential symptoms.

Fc Receptor Inhibition Reduces Susceptibility to Oxidative Stress in Human RPE Cells Treated with Bevacizumab, but not Aflibercept

BACKGROUND/AIMS

VEGF-A is induced by oxidative stress, and functions as a survival factor for various cell types, including retinal pigment epithelial (RPE) cells. Anti-vascular endothelial growth factor (VEGF) drugs like aflibercept and bevacizumab have shown to be most effective in treating neovascular age-related macular degeneration (AMD), however uptake of the drugs might lead to interference with cell physiology. Herein, we evaluated the significance of the Fc receptor (FcR) within this context and moreover explored the impact of VEGF inhibition under normal conditions as well as under oxidative stress, in terms of potential adverse effects.

METHODS

ARPE-19 (human RPE) cells were treated with aflibercept and bevacizumab in presence or absence of H2O2 as oxidative stress stimulus. After 24h cells were evaluated for drug uptake, VEGF-A expression and secretion, levels of intracellular reactive oxygen species (ROS) as well as cell proliferation. Experiments were repeated with cells being pre-incubated with an FcR inhibitor prior to drug application.

RESULTS

Both drugs inhibited extracellular levels of VEGF-A and were taken up into the RPE, resulting in significantly reduced intracellular levels of VEGF-A. When oxidative stress was applied, intracellular ROS levels in cells treated with both drugs rose, and cell proliferation was reduced. Prior incubation with the FcR inhibitor lessened the uptake of bevacizumab, but not aflibercept into RPE cells, and simultaneously enhanced cell survival under oxidative stress conditions.

CONCLUSIONS

Our results indicate that uptake and accumulation of aflibercept and bevacizumab within RPE cells affect the intracellular VEGF-A metabolism negatively, leading to a biologically relevant reduced cell survival under oxidative stress. The FcR plays a substantial role in the uptake of bevacizumab, but not aflibercept, which allows an enhanced RPE cell survival through FcR blockage in an environment dominated by oxidative stress, as clinically significant for various inflammatory retinal disorders.

Ferromagnetic resonance measurements of (Co/Ni/Co/Pt) multilayers with perpendicular magnetic anisotropy

Multilayers of [Co/Ni(t)/Co/Pt]×8 with varying Ni thickness were investigated for possible use as a free layer in magnetic tunnel junctions and spintronics devices. The thickness t of the Ni sub-layer was varied from 0.3 nm to 0.9 nm and the resulting magnetic properties were compared with (Co/Ni) and (Co/Pt) multilayers. As determined from magnetic force microscopy, magnetometry and ferromagnetic resonance measurements, all multilayers exhibited perpendicular magnetic anisotropy. Compared with (Co/Pt) multilayers, the sample with t of 0.9 nm showed almost the same anisotropy field of μ 0 H k = 1.15 T but the damping constant was 40% lower. These characteristics make these multilayers attractive for spin torque based magnetoresistive devices with perpendicular anisotropy.

The effect of disease-modifying antirheumatic drugs on retinal function in the electrophysiological ex vivo model of the isolated perfused vertebrate retina

BACKGROUND

Disease-modifying antirheumatic drugs (DMARDs) have been suggested in the treatment of inflammatory ophthalmological diseases. The aim of the present study was to investigate the effects of these DMARDs on bovine retinal function.

METHODS

Bovine retina preparations were perfused with a standard solution. After recording stable electroretinograms the nutrient solution was substituted by a DMARD medium with varying concentrations of different drugs (etanercept and infliximab) for 30 min. Afterwards b-wave recovery was observed.

RESULTS

Significant decreases in the b-wave amplitude (p < 0.05) were found for etanercept 0.5 mg/ml (p = 0.0022). Infliximab 2 mg/ml (p = 0.1276) did not result in any statistically significant b-wave reduction.

CONCLUSION

The presented data suggest that infliximab might have the better safety profile than etanercept.

Study of vitellogenin in Boophilus annulatus tick larvae and its immunological aspects

Boophilus annulatus is an important one-host tick in the Mediterranean regions and Iran. It can transmit the Babesia bigemina, Babesia bovis and Anaplasma marginale to cattle. Nowadays, immunization programs by tick proteins is one of the potential methods for the control and prevention of tick infestations. Therefore, the characterization and identification of various tick proteins are necessary. Vitellogenin is a precursor of vitellin that is produced in mid gut cells and fat bodies in ticks. In this study, we characterized vitellogenin protein of B. annulatus unfed larvae using one- and two-dimensional electrophoresis and immunoblotting. In one-dimensional immunoblotting, 48, 70, 100, 130 and >250 kDa protein bands positively reacted with immune sera. In two-dimensional immunoblotting many protein spots positively reacted with immune sera. Six of them were analyzed by MALDI-TOF and MALDI-TOF- TOF mass spectrometry. The results showed that amino acid sequences of four immunogenic proteins with molecular weights of 38, 43, 85 and 97 kDa had identity to tick vitellogenin and its homologues (GP80), based on the Mascot search results. It seems that more knowledge on tick proteins including vitellogenin and their characterization could be useful for the development of anti-tick vaccines.

Detection of esterified cholesterol in murine Bruch's membrane wholemounts with a perfringolysin O-based cholesterol marker

PURPOSE

To investigate the effects of Bruch's membrane (BrM) neutral lipid deposition in mouse models and its significance to aging and age-related macular degeneration, it is essential to reliably detect small quantities of neutral lipids including esterified cholesterol (EC). In chorioretinal sections and BrM wholemounts, we tested a novel fluorescent cholesterol marker based on the bacterial toxin perfringolysin O (PFO) and compared results with those obtained with the classic cholesterol dye filipin.

METHODS

An engineered plasmid containing the specific cholesterol binding domain (D4) of PFO fused to green fluorescent protein (GFP) was expressed in cultured E. coli, isolated, purified, and concentrated. A total of 150 BrM-choroid wholemounts and chorioretinal sections of 11- to 13-month-old ApoE(null) mice were prepared and stained with PFO/D4-GFP or filipin for EC. Samples were examined by epifluorescence microscopy.

RESULTS

The fluorescence intensity of PFO/D4-GFP was strong, stable, and, if small quantities of EC were present, superior to filipin. In all specimens, we could sharply locate the PFO/D4-GFP signal to BrM. A semiquantitative evaluation of BrM lipid deposition is possible by measuring PFO/D4-GFP fluorescence intensity.

CONCLUSIONS

The use of PFO/D4-GFP allowed a robust and direct detection of EC in aged murine BrM. In wholemount samples, its strong and stable fluorescence facilitated a semiquantitative evaluation of BrM-EC content over a large area. The patterns of EC deposition in murine BrM wholemounts are comparable with findings in human BrM wholemounts. Perfringolysin O/D4-GFP could be an important tool for investigating the effects of BrM lipid deposition in mouse models.

The concentration-dependent effects of indocyanine green on retinal function in the electrophysiological ex vivo model of isolated perfused vertebrate retina

BACKGROUND

Dye solutions such as indocyanine green (ICG) are used for the staining of intraocular structures. The aim of the presented study was to investigate the effects of ICG on bovine retinal function using different concentrations of ICG.

METHODS

Bovine retina preparations were perfused with a standard solution and the electroretinogram was recorded. The nutrient solution was substituted by an ICG solution at varying concentrations for 45 min. Afterwards the preparations were reperfused with standard solution for at least 85 min.

RESULTS

Significant reductions in b-wave amplitude were found for concentrations of 0.0025% (p = 0.0099) and 0.025% (p = 0.0378). For the concentration of 0.025%, the b-wave amplitude remained significantly decreased (p = 0.0082) after the observation period, but a full recovery of the b-wave was observed for the concentration of 0.0025% (p = 0.1917).

CONCLUSION

Intraocular application of sufficient ICG concentrations for internal limiting membrane staining seems not possible without interfering with retinal function.

Monitoring of the therapeutic efficacy of chloroquine for the treatment of uncomplicated,Plasmodium falciparummalaria in Iran

Between 2002 and 2004, the standardized 28-day protocol recently developed by the World Health Organization was used to explore the efficacy of chloroquine, in the treatment of uncomplicated, Plasmodium falciparum malaria, in five sentinel sites in southern Iran. All but 14 of the 158 patients enrolled (128, 28 and two from the provinces of Sistan-Baluchestan, Hormozgan and Kerman, respectively) were successfully followed-up. The overall frequency of treatment failure by day 28 was 78.5%, with 17.4% of the patients being classed as early treatment failures, 34.7% as late clinical failures, and 26.4% as late parasitological failures. There appeared to be no significant change in the frequency of treatment failure between the 2002-2003 and 2003-2004 transmission seasons, nor any significant between-site variation in the efficacy of chloroquine. Given these observations, the replacement of chloroquine, as the first-line drug for the treatment of uncomplicated, P. falciparum malaria in Iran, was inevitable. Artesunate-sulfadoxine-pyrimethamine is now the recommended first-line treatment, with artemether-lumefantrine used for second-line treatment. The efficacies of these combination therapies are currently being evaluated and monitored.