Following the status of visual cortex over time in patients with macular degeneration reveals atrophy of visually deprived brain regions

Purpose: Previous research has shown atrophy of visual cortex can occur in retinotopic representations of retinal lesions resulting from eye disease. However, the time course of atrophy cannot be established from these cross-sectional studies, which included patients with long-standing disease of varying severity. Our aim therefore was to measure visual cortical structure over time in participants after onset of unilateral visual loss resulting from age-related macular degeneration (AMD). Methods: Inclusion criteria were onset of acute unilateral neovascular AMD with bilateral dry-AMD based on clinical examination. Therefore, substantial loss of unilateral visual input to cortex was relatively well-defined in time. Changes in cortical anatomy were assessed in the occipital lobe as a whole, and in cortical representations of the lesion and intact retina, the lesion and intact projection zones, respectively. Whole brain, T1-weighted MRI was taken at diagnosis (before anti-angiogenic treatment to stabilise the retina), during the 3-4-month initial treatment period, with a long-term follow-up ~5 (range 3.8 – 6.1 years) years later. Results: Significant cortical atrophy was detected at long-term follow-up only, with a reduction in mean cortical volume across the whole occipital lobe. Importantly, this reduction was explained by cortical thinning of the lesion projection zone, which suggests additional changes to those associated with normal ageing. Over the period of study, anti-angiogenic treatment stabilised visual acuity and central retinal thickness, suggesting that the atrophy detected was most likely governed by long-term decreased visual input. Conclusions: Our results indicate that consequences of eye disease on visual cortex are atrophic and retinotopic. Our work also raises the potential to follow the status of visual cortex in individuals over time to inform on how best to treat patients, particularly with restorative techniques

Assessing the structure of the posterior visual pathway in bilateral macular degeneration

Abstract Macular degeneration (MD) embodies a collection of disorders causing a progressive loss of central vision. Cross-sectional MRI studies have revealed structural changes in the grey and white matter in the posterior visual pathway in MD but there remains a need to understand how such changes progress over time. To that end we assessed the posterior pathway, characterising the visual cortex and optic radiations over a ~ 2-year period in MD patients and controls. We performed cross-sectional and longitudinal analysis of the former. Reduced cortical thickness and white matter integrity were observed in patients compared to controls, replicating previous findings. While faster, neither the rate of thinning in visual cortex nor the reduction in white matter integrity during the ~ 2-year period reached significance. We also measured cortical myelin density; cross-sectional data showed this was higher in patients than controls, likely as a result of greater thinning of non-myelinated tissue in patients. However, we also found evidence of a greater rate of loss of myelin density in the occipital pole in the patient group indicating that the posterior visual pathway is at risk in established MD. Taken together, our results revealed a broad decline in grey and white matter in the posterior visual pathway in bilateral MD; cortical thickness and fractional anisotropy show hints of an accelerated rate of loss also, with larger effects emerging in the occipital pole

Improved structure and function in early detected second eye neovascular age-related macular degeneration; FASBAT/EDNA report 1

PURPOSE: Visual Acuity (VA) and structural biomarker assessment before and at 24-months after early detection and routine treatment of second eye involvement with neovascular age-related macular degeneration (nAMD) and additional comparison with the first eye affected. DESIGN: Prospective, 22-centre observational study of participants with unilateral nAMD in the Early Detection of Neovascular AMD (EDNA) study, co-enrolled into the Observing fibrosis, macular atrophy and subretinal highly reflective material, before and after intervention with anti-VEGF treatment (FASBAT) study for an additional 2-year follow-up. PARTICIPANTS: Older adults (>50 years) with new onset nAMD in the first eye. METHODS: Assessment of both eyes with optical coherence tomography (OCT), colour fundus photography (CFP), clinic-measured visual acuity (VA) and quality-of-life (QoL). MAIN OUTCOME MEASURES: Prevalence of Atrophy, Subretinal Hyperreflective Material (SHRM), Intraretinal fluid (IRF), Subretinal fluid (SRF) and changes in VA over the study duration in both the first and second eyes affected with nAMD. Composite QoL scores over time. RESULTS: Of 431 participants recruited to the FASBAT study, the second eye converted to nAMD in 100 participants at a mean of 18.9 months. VA was 18 letters better at the time of early diagnosis in the second eye compared with conventional diagnosis in the first eye (72.9 vs 55.6 letters). 24.9-months post-conversion in the second eye, VA was 69.5 letters compared with at a similar matched time point in the first eye (59.7 letters; 18.9 months). A greater proportion of participants had vision >70 letters in the second eye versus the first eye, 24.9-months post-conversion (61 vs 38). Prevalence of SHRM and IRF was lower in the second eye compared with the first eye at 24.9-months post-conversion to nAMD. However, SRF prevalence was greater in the second eye at 24.9-months post-conversion. The development and progression of total area of atrophy appears similar in both eyes. Mean composite QoL scores increased over time, with a significant correlation between VA for the second eye only 24.9 months post-conversion. CONCLUSION: This study has shown that early detection of exudative AMD in the second eye is associated with reduced prevalence of SHRM and IRF and greater visual acuity which is significantly correlated with maintained quality-of-life

Extraction, characterization and biological studies of phytochemicals from Mammea suriga

The present work involves extraction of phytochemicals from the root bark of a well-known Indian traditional medicinal plant, viz. Mammea suriga, with various solvents and evaluation of their in vitro antimicrobial and antioxidant activities using standard methods. The phytochemical analysis indicates the presence of some interesting secondary metabolites like flavonoids, cardiac glycosides, alkaloids, saponins and tannins in the extracts. Also, the solvent extracts displayed promising antimicrobial activity against Staphylococcus aureus, Bacillus subtilis and Cryptococcus neoformans with inhibition zone in a range of 20â33 mm. Further, results of their antioxidant screening revealed that aqueous extract (with IC50 values of 111.51±1.03 and 31.05±0.92 μg/mL in total reducing power assay and DPHH radical scavenging assay, respectively) and ethanolic extract (with IC50 values of 128.00±1.01 and 33.25±0.89 μg/mL in total reducing power assay and DPHH radical scavenging assay, respectively) were better antioxidants than standard ascorbic acid. Interestingly, FT-IR analysis of each extract established the presence of various biologically active functional groups in it. Keywords: Mammea suriga, Phytochemical analysis, Antimicrobial activity, Antioxidant assay, FT-IR analysi

Assessing the structure of the posterior visual pathway in bilateral macular degeneration

Abstract Macular degeneration (MD) embodies a collection of disorders causing a progressive loss of central vision. Cross-sectional MRI studies have revealed structural changes in the grey and white matter in the posterior visual pathway in MD but there remains a need to understand how such changes progress over time. To that end we assessed the posterior pathway, characterising the visual cortex and optic radiations over a ~ 2-year period in MD patients and controls. We performed cross-sectional and longitudinal analysis of the former. Reduced cortical thickness and white matter integrity were observed in patients compared to controls, replicating previous findings. While faster, neither the rate of thinning in visual cortex nor the reduction in white matter integrity during the ~ 2-year period reached significance. We also measured cortical myelin density; cross-sectional data showed this was higher in patients than controls, likely as a result of greater thinning of non-myelinated tissue in patients. However, we also found evidence of a greater rate of loss of myelin density in the occipital pole in the patient group indicating that the posterior visual pathway is at risk in established MD. Taken together, our results revealed a broad decline in grey and white matter in the posterior visual pathway in bilateral MD; cortical thickness and fractional anisotropy show hints of an accelerated rate of loss also, with larger effects emerging in the occipital pole

Attenuation of lysyl oxidase and collagen gene expression in keratoconus patient corneal epithelium corresponds to disease severity

PURPOSE: Keratoconus (KC) is characterized by progressive vision loss due to corneal thinning and structural abnormalities. It is hypothesized that KC is caused by deregulated collagen levels and collagen fibril-maturating enzyme lysyl oxidase (LOX). Further, it is currently not understood whether the gene expression deregulated by the corneal epithelium influences KC pathogenesis. We studied (i) the expressions of the LOX, collagen I (COL IA1), collagen IV (COL IVA1), MMP9, and IL6 genes in KC corneal epithelia, (ii) validated their expression levels in patient tissues, and (iii) correlated expression levels with KC disease severity. The primary goal of this study was to evaluate the importance of these genes in the progression of KC. METHODS: We analyzed the gene expression levels of the key proteins LOX, collagens (COL IA1 and COL IVA1), MMP9, and IL6 in debrided corneal epithelia from a large cohort of KC patients (90 eyes) and compared them to control patients (52 eyes) without KC. We measured the total LOX activity in the tears of KC patients compared to controls. We also correlated the protein expression levels of LOX and collagens by immunohistochemistry (IHC) in primary tissues from KC patients (27 eyes) undergoing keratoplasty compared to healthy donor corneas (15 eyes). RESULTS: We observed a significant reduction in LOX transcript levels in KC corneal epithelia, and LOX activity in KC tears correlated with disease severity. Collagen transcripts were also reduced in KC while MMP9 transcript levels were upregulated and correlated with disease severity. IL6 was moderately increased in KC patients. IHC demonstrated a reduction in the protein expression levels of LOX in the epithelium and collagen IV in the basement membrane of KC patients compared to healthy donor corneas. CONCLUSIONS: The data demonstrates that the structural deformity of the KC cornea may be dependent on reduced expressions of collagens and LOX, as well as on MMP9 elevated by the corneal epithelium

The MATE trial: a multicentre, mixed-methodology, pilot, randomised controlled trial in neovascular age-related macular degeneration

Abstract Background/objectives In healthcare research investigating complex interventions, gaps in understanding of processes can be filled by using qualitative methods alongside a quantitative approach. The aim of this mixed-methods pilot trial was to provide feasibility evidence comparing two treatment regimens for neovascular age-related macular degeneration (nAMD) to inform a future large-scale randomised controlled trial (RCT). Subjects/methods Forty-four treatment-naïve nAMD patients were followed over 24 months and randomised to one of two treatment regimens: standard care (SC) or treat and extend (T&E). The primary objective evaluated feasibility of the MATE trial via evaluations of screening logs for recruitment rates, nonparticipation and screen fails, whilst qualitative in-depth interviews with key study staff evaluated the recruitment phase and running of the trial. The secondary objective assessed changes in visual acuity and central retinal thickness (CRT) between the two treatment arms. Results The overall recruitment rate was 3.07 participants per month with a 40.8% non-participation rate, 18.51% screen-failure rate and 15% withdrawal/non-completion rate. Key themes in the recruitment phase included human factors, protocol-related issues, recruitment processes and challenges. Both treatment regimens showed a trend towards a visual acuity gain at month 12 which was not maintained at month 24, whilst CRT reduced similarly in both regimens over the same time period. These were achieved with one less treatment following a T&E regimen. Conclusion This mixed-methodology, pilot RCT achieved its pre-defined recruitment, nonparticipation and screen failure rates, thus deeming it a success. With some minor protocol amendments, progression to a large-scale RCT will be achievable