Transpupillary thermotherapy for choroidal melanoma:Tumor control and visual results in 100 consecutive cases

Objective: The authors evaluated the results of primary transpupillary thermotherapy for choroidal melanoma in 100 cases. Design: Prospective nonrandomized analysis of treatment method. Participants: One hundred patients with choroidal melanoma were studied. Main Outcome Measures: Tumor response, ocular side effects, and visual results. Results: Of 100 consecutive patients with choroidal melanoma treated with transpupillary thermotherapy, the mean tumor basal diameter was 7.1 mm and tumor thickness was 2.8 mm. The tumor margin touched the optic disc in 34 eyes (34%) and was beneath the fovea in 42 eyes (42%). Documented growth was present in 64 eyes (64%), and known clinical risks for growth were present in all of the remaining 36 eyes (36%), with an average of 4 of 5 statistical risk factors for growth per tumor. After a mean of three treatment sessions and 14 months of follow-up, the mean tumor thickness was reduced to 1.4 mm. Treatment was successful in 94 eyes (94%) and failed in 6 eyes (6%). Three patients with amelanotic tumors showed no initial response to thermotherapy, but subsequent intravenous indocyanine green administration during thermotherapy resulted in improved heat absorption and tumor regression to a flat scar. The six eyes classified as treatment failures included four eyes with tumors that showed partial or no response to thermotherapy, thus requiring plaque radiotherapy or enucleation, and two eyes with recurrence, subsequently controlled with additional thermotherapy. After treatment, the visual acuity was the same (within 1 line) or better than the pretreatment visual acuity in 58 eyes (58%) and worse in 42 eyes (42%). The main reasons for poorer vision included treatment through the foveola for subfoveal tumor (25 eyes), retinal traction (10 eyes), retinal vascular obstruction (5 eyes), optic disc edema (1 eye), and unrelated ocular ischemia (1 eye). Temporal location (versus nasal and superior, P = 0.02) and greater distance from the optic disc (P = 0.04) were risks for retinal traction. Conclusions: Transpupillary thermotherapy may be an effective treatment for small posterior choroidal melanoma, especially those near the optic disc and fovea. Despite satisfactory local tumor control, ocular side effects can result in decreased vision. Longer follow- up will be necessary to assess the impact of thermotherapy on ultimate local tumor control and metastatic disease.

External beam radiotherapy in exudative age-related macular degeneration: a pooled analysis of phase I data

In recent years external beam radiotherapy (EBRT) has been proposed as a treatment for the wet form of age-related macular degeneration (AMD) where choroidal neovascularization (CNV) is the hallmark. While the majority of pilot (Phase I) studies have reported encouraging results, a few have found no benefit, i.e. EBRT was not found to result in either improvement or stabilization of visual acuity of the treated eye. The natural history of visual loss in untreated CNV of AMD is highly variable. Loss of vision is influenced mainly by the presenting acuity, and size and composition of the lesion, and to a lesser extent by a variety of other factors. Thus the variable outcome reported by the small Phase I studies of EBRT published to date may simply reflect the variation in baseline factors. We therefore obtained information on 409 patients treated with EBRT from eight independent centres, which included details of visual acuity at baseline and at subsequent follow-up visits. Analysis of the data showed that 22.5% and 14.9% of EBRT-treated eyes developed moderate and severe loss of vision, respectively, during an average follow-up of 13 months. Initial visual acuity, which explained 20.5% of the variation in visual loss, was the most important baseline factor studied. Statistically significant differences in loss of vision were observed between centres, after considering the effects of case mix factors. Comparisons with historical data suggested that while moderate visual loss was similar to that of the natural history of the disease, the likelihood of suffering severe visual loss was halved. However, the benefit in terms of maintained/improved vision in the treated eye was modest.

Alternative treatments to inhibit VEGF in age-related choroidal neovascularisation: 2-year findings of the IVAN randomised controlled trial

Background: Bevacizumab has been suggested to have similar effectiveness to ranibizumab for treatment of neovascular age-related macular degeneration. The Inhibition of VEGF in Age-related choroidal Neovascularisation (IVAN) trial was designed to compare these drugs and different regimens. Here, we report the findings at the prespecified 2-year timepoint. Methods: In a multicentre, 2×2 factorial, non-inferiority randomised trial, we enrolled adults aged at least 50 years with active, previously untreated neovascular age-related macular degeneration and a best corrected distance visual acuity (BCVA) of at least 25 letters from 23 hospitals in the UK. Participants were randomly assigned (1:1:1:1) to intravitreal injections of ranibizumab (0·5 mg) or bevacizumab (1·25 mg) in continuous (every month) or discontinuous (as needed) regimens, with monthly review. Study participants and clinical assessors were masked to drug allocation. Allocation to continuous or discontinuous treatment was masked up to 3 months, at which point investigators and participants were unmasked. The primary outcome was BCVA at 2 years, with a prespecified non-inferiority limit of 3·5 letters. The primary safety outcome was arterial thrombotic event or hospital admission for heart failure. Analyses were by modified intention to treat. This trial is registered, number ISRCTN92166560. Findings: Between March 27, 2008, and Oct 15, 2010, 628 patients underwent randomisation. 18 were withdrawn; 610 received study drugs (314 ranibizumab; 296 bevacizumab) and were included in analyses. 525 participants reached the visit at 2 years: 134 ranibizumab in continuous regimen, 137 ranibizumab in discontinuous regimen, 127 bevacizumab in continuous regimen, and 127 bevacizumab in discontinuous regimen. For BCVA, bevacizumab was neither non-inferior nor inferior to ranibizumab (mean difference -1·37 letters, 95% CI -3·75 to 1·01; p=0·26). Discontinuous treatment was neither non-inferior nor inferior to continuous treatment (-1·63 letters, -4·01 to 0·75; p=0·18). Frequency of arterial thrombotic events or hospital admission for heart failure did not differ between groups given ranibizumab (20 [6%] of 314 participants) and bevacizumab (12 [4%] of 296; odds ratio [OR] 1·69, 95% CI 0·80-3·57; p=0·16), or those given continuous (12 [4%] of 308) and discontinuous treatment (20 [7%] of 302; 0·56, 0·27-1·19; p=0·13). Mortality was lower with continuous than discontinuous treatment (OR 0·47, 95% CI 0·22-1·03; p=0·05), but did not differ by drug group (0·96, 0·46-2·02; p=0·91). Interpretation: Ranibizumab and bevacizumab have similar efficacy. Reduction in the frequency of retreatment resulted in a small loss of efficacy irrespective of drug. Safety was worse when treatment was administered discontinuously. These findings highlight that the choice of anti-VEGF treatment strategy is less straightforward than previously thought.

Retinal and choroidal responses to panretinal photocoagulation: an ultrastructural perspective

BACKGROUND: There have been few histological or ultrastructural studies of the outer retina and choriocapillaris following panretinal photocoagulation therapy. This investigation examines the long-term morphological effects of panretinal photocoagulation in two patients with type II diabetes who had received laser treatment more than 6 months prior to death.

METHODS: Regions of retina and choroid from each patient were fixed in 2.5% glutaraldehyde, dissected out and examined using light microscopy and scanning and transmission electron microscopy.

RESULTS: After removing the neural retina, scanning electron microscopy of non-photocoagulated areas of the eye cups revealed normal cobblestone-like retinal pigment epithelial (RPE) cells. Regions with laser scars showed little RPE infiltration into the scar area, although large rounded cells often appeared in isolation within these areas. Sections of the retina and choroid in burn regions showed a complete absence of the outer nuclear layer and photoreceptor cells, with the inner retinal layers lying in close apposition to Bruch's membrane. Non-photocoagulated regions of the retina and choroid appeared normal in terms of both cell number and cell distribution. The RPE layer was absent within burn scars but many RPE-like cells appeared markedly hypertrophic at the edges of these regions. Bruch's membrane always remained intact, although the underlying choriocapillaris was clearly disrupted at the point of photocoagulation burns, appearing largely fibrosed and non-perfused. Occasional choroidal capillaries occurring in this region were typically small in profile and had plump non-fenestrated endothelium.

CONCLUSIONS: This study outlines retinal and choroidal cell responses to panretinal photocoagulation in diabetic patients and demonstrates an apparent reduction in the capacity of these tissues to repair laser damage.

In vitro viability of choroidal melanomata following pre-enucleation irradiation

In a group of eighteen patients with uveal melanomas, seven underwent low-dose pre-enucleation irradiation of approximately 2000 cGy. All the tumours were propagated in tissue culture and the growth characteristics of tumour cells from irradiated eyes were compared with tumour cells from non-irradiated eyes. Cultures were observed with phase-contrast microscopy, and radioactive thymidine labelling was used to study cell turnover. Although tissue samples from peripheral areas of irradiated tumours produced a mixture of viable and non-viable cells, with reduced ability to attach to substrate, central regions of irradiated tumours contained viable cells which propagated freely in tissue culture.

Endocytosis in the retinal and choroidal microcirculation

The endocytosis of horseradish peroxidase (HRP) by the vascular cells of retinal and choroidal blood vessels was compared in immersion and perfusion fixed eyes from individual rats. The mechanisms of endocytosis of HRP appeared identical in both retinal and choroidal vessels. The bulk of internalised tracer occurred in macropinosomes 300-400 nm in diameter. Tracer was localised to a 20-30 nm layer on the internal aspect of the limiting membrane. This layer was coincident with the glycocalyx of the luminal plasma membrane as revealed by ruthenium redosmium tetroxide staining. Horseradish peroxidase was also internalised by a small scattered population of vesicles (100-130 nm in diameter). The size of these vesicles suggested that they may have arisen from clathrin coated regions of the plasma membrane. It is suggested that the endocytosis of HRP in retinal and choroidal vascular endothelium occurs as a function of plasma membrane recycling. Horseradish peroxidase may also be internalised as a 'contaminant' of the glycocalyx in coated pits involved in receptor mediated endocytosis. The smooth 80 nm plasmalemmal caveolae of the retinal and choroidal vascular endothelial cells did not appear to participate either in absorptive endocytosis or vesicular transport.

Electron microscopic features of experimental choroidal neovascularization

We produced choroidal neovascularization in the rhesus monkey by diminishing the blood supply to the inner retina and producing defects in Bruch's membrane by photocoagulation. The neovascular fronds which developed either infiltrated the subretinal space or proliferated through necrotic and gliotic retina into the vitreous cavity. Sequential electron microscopic sections of neovascular fronds in the subretinal space demonstrated that the advancing capillary sprouts were composed of primitive endothelial tubes surrounded by pericytes and enmeshed in a loose basement-membrane-like substance. More mature capillaris and displayed endothelial fenestrations and endothelial-pericyte membranous contacts. Large neovascular fronds developed major feeding vessels that closely resembled normal small choroidal arteries and veins. Retinal pigment epithelial cells in various guises were in constant association with proliferating neovascular networks.

Morphologic fluorescein angiographic, and light microscopic features of experimental choroidal neovascularization

We induced choroidal neovascularization in the rhesus monkey by impoverishing the blood supply to the inner retina and producing defects in Bruch's membrane by photocoagulation. Fourteen of 46 eyes undergoing photocoagulation developed neovascular fronds which were identified and categorized by histopathologic examination and fluorescein angiography. All new vessels gained access to the retina through defects in Bruch's membrane at the site of photocoagulation marks. In eight eyes the new vessels remained localized to the immediate vicinity of photocoagulation marks. In four eyes neovascular fronds infiltrated the subretinal space for distances up to 6 disk diameters from the point of entry into the retina. In the two eyes choroidovitreal neovascular complexes developed but rapidly regressed shortly after gaining the vitreous cavity. Fluorescein angiography demonstrated that all neovascular fronds were grossly incompetent to dye but that formed feeding channels had some degree of integrity. Light microscopic studies showed the proliferating networks to be composed of capillaries with well-formed basement membranes and more mature vessels with the basic structure of choroidal arteries and veins.

Myeloid cells expressing VEGF and arginase-1 following uptake of damaged retinal pigment epithelium suggests potential mechanism that drives the onset of choroidal angiogenesis in mice

Whilst data recognise both myeloid cell accumulation during choroidal neovascularisation (CNV) as well as complement activation, none of the data has presented a clear explanation for the angiogenic drive that promotes pathological angiogenesis. One possibility that is a pre-eminent drive is a specific and early conditioning and activation of the myeloid cell infiltrate. Using a laser-induced CNV murine model, we have identified that disruption of retinal pigment epithelium (RPE) and Bruch's membrane resulted in an early recruitment of macrophages derived from monocytes and microglia, prior to angiogenesis and contemporaneous with lesional complement activation. Early recruited CD11b(+) cells expressed a definitive gene signature of selective inflammatory mediators particularly a pronounced Arg-1 expression. Accumulating macrophages from retina and peripheral blood were activated at the site of injury, displaying enhanced VEGF expression, and notably prior to exaggerated VEGF expression from RPE, or earliest stages of angiogenesis. All of these initial events, including distinct VEGF (+) Arg-1(+) myeloid cells, subsided when CNV was established and at the time RPE-VEGF expression was maximal. Depletion of inflammatory CCR2-positive monocytes confirmed origin of infiltrating monocyte Arg-1 expression, as following depletion Arg-1 signal was lost and CNV suppressed. Furthermore, our in vitro data supported a myeloid cell uptake of damaged RPE or its derivatives as a mechanism generating VEGF (+) Arg-1(+) phenotype in vivo. Our results reveal a potential early driver initiating angiogenesis via myeloid-derived VEGF drive following uptake of damaged RPE and deliver an explanation of why CNV develops during any of the stages of macular degeneration and can be explored further for therapeutic gain.

Attention-based modulation of tactile stimuli: A comparison between prefrontal lesion patients and healthy age-matched controls

Objectives: To investigate the role of the prefrontal cortex in attention-based modulation of cortical somatosensory processing.

Methods: Six prefrontal stroke patients were compared with eleven neurologically intact older adults during a vibrotactile discrimination task. All subjects attended to stimuli on one digit while ignoring distracter stimuli on a separate digit of the same hand. Subjects were required to report infrequent targets on the attended digit only. Throughout testing electroencephalography was used to measure event-related potentials for both task-relevant and irrelevant stimuli.

Results: Prefrontal patients demonstrated significant changes in cortical somatosensory processing based on attention compared to age-matched controls. This was evident both in early unimodal somatosensory processing (i.e. P100) and in later cortical processing stages (i.e. long-latency positivity). Moreover, there was a tendency towards a tonic loss of inhibition over early somatosensory cortical processing (i.e. P50).

Conclusions: The attention-based modulation noted for neurologically intact older adults was absent in prefrontal lesion patients.

Significance: The present study highlights the important role of prefrontal regions in sustaining inhibition over early sensory cortical processing stages and in modifying somatosensory transmission based on task-relevance. Notably these deficits extend beyond those previously shown to occur as a function of age.

Treatment of choroidal neovascularisation secondary to membranoproliferative glomerulonephritis type II with intravitreal ranibizumab

Membranoproliferative glomerulonephritis type II (MPGN II) is characterised by electron-dense deposits of complement components in the glomerular basement membrane and retinal pigment epithelium. Approximately, 10% of affected individuals develop serious ocular complications similar to age-related macular degeneration such as choroidal neovascularisation (CNV), which has been managed with photocoagulation or photodynamic therapy; however, these treatments can impact visual acuity. We report the case of a 42-year-old woman with MPGN II presenting with decreased visual acuity and paracentral scotoma in her left eye due to an extrafoveal choroidal neovascular membrane (growth of new vessels under the retina). The patient was successfully treated with intravitreal ranibizumab (Lucentis) with restoration of visual function. This case highlights the successful management of CNV secondary to MPGN II with the antivascular endothelial growth factor agent ranibizumab and emphasises the importance of early referral of patients with MPGN II who are reporting of visual 'distortion'.

The role of WNT singling activation and its blockage in the focal retinal lesion of Ccl2-/-/Cx3cr1-/- mice with and without rd8 background

Purpose: The canonical Wnt signaling is activated by retinal injury. Under disease conditions, the Wnt mediates inflammatory responses. Inflammation has been detected in age-related macular degeneration (AMD) retinas and Ccl2-/-/Cx3cr1-/- (DKO) mice with or without rd8 background, a model with progressive AMD-like lesions including focal photoreceptor/RPE degeneration and A2E accumulation. We evaluated the effects of Wnt-β-catenin activation and an antibody against LRP6, the co-receptor of Wnt on these two models.

Methods: anti-LRP6 antibody (2F1, 1 μl of 5 μg/μL) was intravitreally injected into the right eyes in 3 separate experiments (DKOrd8, N=35; DKO, N=10). The left eyes were injected with mouse IgG as controls. Fundoscopy was taken before injection and sequentially monthly after injection. Two months after injection, light-adapted ERG responses were recorded; then the eyes were harvested for histopathology, the determination of retinal A2E, and molecular analysis. The microarray of ocular mRNA of 92 Wnt genes was compared between the treated and the control eyes. The phosphorylated types of LRP6 and β-catenin and endogenous forms of the proteins were assayed by Western blotting.

Results: For DKOrd8 mice, the fundus showed a slower progression or alleviation of retinal lesions in the right eyes as compared to the left eyes. Among 35 pairs of eyes, 26 (74.3%) were improved, 7 (20%) stayed the same and 2 (5.7%) remained progressing. Histology confirmed the clinical observation. Light-adapted ERG of the treated eyes exhibited larger amplitudes compared to control eyes (n=6), with greater improvements under UV light stimulus. There was a significantly lower A2E in the treated eyes compared to controls. Microarray of 92 Wnt genes expression pattern was similar in both eyes. Western blotting indicated local administration of 2F1 antibody to suppress the activation of Wnt pathway in the retina. For DKO mice, the treatment improved ERG but less effect on RPE degeneration.

Conclusions: The canonical Wnt signaling plays a role in the focal retina lesion of both DKOrd8 and DKO mice; and intravitreal anti-LRP6 antibody might be neuroprotective via deactivation of canonical Wnt pathway.