Extracts from "clinical evidence": age related macular degeneration

Transforming growth factor-beta inhibition reduces progression of early choroidal neovascularization lesions in rats: P17 and P144 peptides

The purpose of this study was to assess the effects of transforming growth factor beta (TGF-β) inhibitor peptides (P17 & P144) on early laser-induced choroidal neovascularization (LI-CNV) lesions in rats, two weeks after laser CNV induction. Seventy-one Long Evans rats underwent diode laser application in an established LI-CNV model. Baseline fluorescein angiography (FA) was performed 14 days following laser procedure, and treatments were administered 16 days post-laser application via different administration routes. Intravenous groups included control (IV-Control), P17 (IV-17), and P144 (IV-144) groups, whereas intravitreal groups included P17 (IVT-17), P144 (IVT-144), and a mixture of both peptides (IVT-17+144) (with fellow eyes receiving vehicle alone). CNV evolution was assessed using FA performed weekly for four weeks after treatment. Following sacrifice, VEGF, TGF-β, COX-2, IGF-1, PAI-1, IL-6, MMP-2, MMP-9, and TNF-α gene expression was assessed using RT-PCR. VEGF and p-SMAD2 protein levels were also assessed by western-blot, while MMP-2 activity was assessed with gelatin zymography. Regarding the FA analysis, the mean CNV area was lower from the 3^rd week in IVT-17 and IVT-144 groups, and also from the 2^nd week in IVT-17+144. Biochemical analysis revealed that gene expression was lower for VEGF and COX-2 genes in IV-17 and IV-144 groups, VEGF gene in IVT-17+144 group and MMP-2 gene in IVT-17 and IVT-144 groups. VEGF protein expression was also decreased in IV-17, IV-144, IVT-17 and IVT-144, whereas pSMAD-2 levels were lower in IV-17, IV-144 and IVT-17+144 groups. Zymogram analysis revealed decreased MMP-2 activity in IV-17, IV-144, IVT-17 and IVT-144 groups. These data suggest that the use of TGF-β inhibitor peptides (P17 & P144) decrease the development of early CNV lesions by targeting different mediators than those typically affected using current anti-angiogenic therapies. Its potential role in the treatment of early CNV appears promising as a single therapy or adjuvant to anti-VEGF drugs.

Metric properties of the MacDQoL, individualized macular-disease-specific quality of life instrument, and newly identified subscales in French, German, Italian, and American populations

OBJECTIVES

The aims of this analysis were to confirm the UK results in other countries and to explore the possibility of subscales of the 25-Item Macular disease Dependent Quality of Life (MacDQoL) questionnaire.

METHODS

Two clinical studies were pooled. Principal components analyses (Varimax) were conducted on baseline data from each country and from all combined. Factorial structures were compared between countries, and Cronbach alpha values were used to identify item clusters. Four groups of patients were created according to visual acuity (VA) in the best eye (BE < 10/20; BE ≥ 10/20) and worst eye (WE < 10/100; WE ≥ 10/100). These groups were used to investigate (analysis of variance) the sensitivity of MacDQoL to VA impairment and to compare it with the NEI-VFQ-25 generic visual function questionnaire.

RESULTS

A total of 797 patients (mean age 76.8 years; 55.8% women) had wet age-related macular degeneration (AMD). Strong correlations between the MacDQoL items (r > 0.48) and factor loadings > 0.49 on a forced one-factor analysis supported the use of an average weighted impact score. Four constructs (Cronbach alpha > 0.8) were derived, represented by the labels: Essential tasks, Family/social life, Activities/capabilities, and Embarrassment. The structure did not differ among the four countries involved, except one item (Finance), which has been excluded. Patients with BE VA <10/20 and WE VA <10/100 produced significantly worse overall scores than those with BE VA >10/20 and WE VA >10/100 (MacDQoL P < 0.0001; NEI-VFQ-25 P < 0.0001).

CONCLUSIONS

The analysis confirmed the metric properties of the MacDQoL. The MacDQoL offers a broad individualized measure of the impact of MD on quality of life.

Genetic basis of inherited macular dystrophies and implications for stem cell therapy

Untreatable hereditary macular dystrophy (HMD) presents a major burden to society in terms of the resulting patient disability and the cost to the healthcare provision system. HMD results in central vision loss in humans sufficiently severe for blind registration, and key issues in the development of therapeutic strategies to target these conditions are greater understanding of the causes of photoreceptor loss and the development of restorative procedures. More effective and precise analytical techniques coupled to the development of transgenic models of disease have led to a prolific growth in the identification and our understanding of the genetic mutations that underly HMD. Recent successes in driving differentiation of pluripotent cells towards specific somatic lineages have led to the development of more efficient protocols that can yield enriched populations of a desired phenotype. Retinal pigmented epithelial cells and photoreceptors derived from these are some of the most promising cells that may soon be used in the treatment of specific HMD, especially since rapid developments in the field of induced pluripotency have now set the stage for the production of patient-derived stem cells that overcome the ethical and methodological issues surrounding the use of embryonic derivatives. In this review we highlight a selection of HMD which appear suitable candidates for combinatorial restorative therapy, focusing specifically on where those photoreceptor loss occurs. This technology, along with increased genetic screening, opens up an entirely new pathway to restore vision in patients affected by HMD.

Burden of illness, visual impairment and health resource utilisation of patients with neovascular age-related macular degeneration: results from the UK cohort of a five-country cross-sectional study

BACKGROUND/AIMS

Quantitative data regarding the impact of neovascular age-related macular degeneration (NV-AMD) on individuals and society is a prerequisite for rational decision-making processes when evaluating alternative treatments for the disease.

METHODS

75 bilateral NV-AMD (patients) and 91 elderly non-AMD (controls) subjects forming the UK cohort of an international cross-sectional, observational study were independently analysed. Subjects completed a telephone survey including the National Eye Institute Visual Function Questionnaire (NEI-VFQ-25), the EuroQol (EQ-5D), the Hospital Anxiety and Depression Scale (HADS), history of falls and health resource utilisation.

RESULTS

Patients with NV-AMD reported substantially worse vision-related functioning and overall well-being, including higher depression scores, than controls after adjusting for age, gender and co-morbidities (adjusted mean scores: NEI-VFQ-25 overall 52.7 vs 90.7, p<0.0001; EQ-5D 0.67 vs 0.77, p = 0.0273; HADS depression 6.8 vs 4.0, p = 0.0026). Significantly more patients reported a need for assistance with daily activities compared with controls (25.3% vs 6.6%, p = 0.003). Total annual healthcare utilisation costs were more than sevenfold higher for patients with AMD compared with controls ( pound 3,823.89 vs pound 517.05, respectively; p<0.0001)

CONCLUSIONS

Patients with NV-AMD show a significant decline in quality of life and increased need for daily living assistance compared to a control population without AMD. With the availability of effective new therapies there is a need for improved early access to treatment.

Screening for age-related macular degeneration using nonstereo digital fundus photographs

Age-related macular degeneration (AMD) is a disease with significant visual morbidity and accounts for the majority of blind registrations in the developed world including the UK. Certain forms of neovascular AMD are amenable to treatment but require expeditious referral to a retinal specialist.

AIM

To evaluate the possibility of using nonstereo fundus photographs as a low-cost screening tool for neovascular AMD.

DESIGN

Retrospective review of patients referred to the macular clinic of a teaching hospital in London.

METHODS

A total of 198 randomised digital fundus photographs, without any other clinical information, were presented to two independent ophthalmic interns who graded them into one of the three categories: normal, age-related maculopathy (ARM), or neovascular age-related macular degeneration (AMD) to determine the urgency of referral to clinic. The results were compared with the known diagnosis for each patient and sensitivities and specificities for each diagnostic category calculated.

RESULTS

The intraobserver Kappa statistic was 0.75 and 0.91 for grader 1 and 2, respectively. The interobserver Kappa was 0.54. The mean sensitivity and specificity for the identification of ARM was 60.5 and 76.3%, respectively The mean sensitivity and specificity for the identification of AMD was 85.7 and 78.8%, respectively.

CONCLUSION

Nonstereo digital fundus photograph is a reasonable screening tool for CNV and may aid in decreasing the visual morbidity it causes by enabling timely referrals and treatment.

Lycopene but not lutein nor zeaxanthin decreases in serum and lipoproteins in age-related macular degeneration patients

BACKGROUND

Epidemiological studies have established that a low serum concentration of carotenoids was associated with risk of Age-Related Macular Degeneration (ARMD). The aim of this study was to determine carotenoid levels in serum and in different lipoprotein fractions in patients diagnosed for ARMD and in matched control group.

METHOD

Thirty-four ARMD patients and 21 control subjects from Brest area (France) have been included to this study. Lipoproteins have been separated from serum by gradient density ultracentrifugation. We measured concentration of carotenoids and tocopherols in serum and in different lipoprotein fractions by HPLC.

RESULTS

No difference was observed between ARMD patients and control subjects in total serum carotenoids. Individual carotenoid levels showed that only lycopene was decreased significantly in serum, LDL and HDL fractions in patients (P<0.05). Concentrations in serum and lipoparticle fractions of lutein and zeaxanthin, the major pigments present in macula were not modified between both groups.

CONCLUSIONS

Lycopene, as liposoluble antioxidant nutrient, is the only carotenoid altered in ARMD patients. It cannot be excluded that this effect is related to different dietary habits, but we hypothesise that lower lycopene status could result also from specific antioxidant protection of lutein and zeaxanthin by lycopene.

Dietary analysis and patterns of nutritional supplement use in normal and age-related macular disease affected subjects: a prospective cross-sectional study

Background

Poor diet is thought to be a risk factor for many diseases, including age-related macular disease (ARMD), which is the leading cause of blind registration in those aged over 60 years in the developed world. The aims of this study were 1) to evaluate the dietary food intake of three subject groups: participants under the age of 50 years without ARMD (U50), participants over the age of 50 years without ARMD (O50), and participants with ARMD (AMD), and 2) to obtain information on nutritional supplement usage.

Methods

A prospective cross-sectional study designed in a clinical practice setting. Seventy-four participants were divided into three groups: U50; 20 participants aged < 50 years, from 21 to 40 (mean ± SD, 37.7 ± 10.1 years), O50; 27 participants aged > 50 years, from 52 to 77 (62.7 ± 6.8 years), and ARMD; 27 participants aged > 50 years with ARMD, from 55 to 79 (66.0 ± 5.8 years). Participants were issued with a three-day food diary, and were also asked to provide details of any daily nutritional supplements. The diaries were analysed using FoodBase 2000 software. Data were input by one investigator and statistically analysed using Microsoft Excel for Microsoft Windows XP software, employing unpaired t-tests.

Results

Group O50 consumed significantly more vitamin C (t = 3.049, p = 0.005) and significantly more fibre (t = 2.107, p = 0.041) than group U50. Group ARMD consumed significantly more protein (t = 3.487, p = 0.001) and zinc (t = 2.252, p = 0.029) than group O50. The ARMD group consumed the highest percentage of specific ocular health supplements and the U50 group consumed the most multivitamins.

Conclusions

We did not detect a deficiency of any specific nutrient in the diets of those with ARMD compared with age- and gender-matched controls. ARMD patients may be aware of research into use of nutritional supplementation to prevent progression of their condition.

Photodynamic therapy with verteporfin is effective, but how big is its effect? Results of a systematic review

BACKGROUND

In 2001 the National Institute for Clinical Excellence (NICE) was asked to issue guidance for England and Wales on the use of photodynamic therapy (PDT). This process has been protracted, partly because of a dispute over the magnitude of beneficial effect. This article examines the origins of the debate about the true treatment effect size for PDT with verteporfin.

METHODS

A systematic review of the clinical effectiveness of PDT compared with current practice was undertaken. Searches in Medline, Embase, the Cochrane Library, and the Internet, updated to January 2003, revealed two fully published and four ongoing randomised controlled trials.

RESULTS

The results of the two published trials (TAP and VIP) consistently showed that overall, PDT with verteporfin is more effective than placebo in slowing the rate of vision loss. In the TAP trial, 12 or more subgroup analyses were undertaken on the primary outcome measure and in VIP, 10 subgroup analyses but only on a subset of the trial participants. Subgroup analysis results were found to be inconsistent between the two trials, with VIP suggesting that verteporfin was equally effective in occult as in mixed lesions and TAP suggesting that verteporfin was more effective in the predominantly classic subgroup.

DISCUSSION

For several reasons it was considered that the most likely estimate of the predominantly classic subgroup effect size was the whole trial result. This has implications for the relationship between cost and benefit, the subject of intense debate. Results of the ongoing trials should help to clarify this subgroup effect size issue.

A randomised controlled trial investigating the effect of nutritional supplementation on visual function in normal, and age-related macular disease affected eyes: design and methodology [ISRCTN78467674]

BACKGROUND

Age-related macular disease is the leading cause of blind registration in the developed world. One aetiological hypothesis involves oxidation, and the intrinsic vulnerability of the retina to damage via this process. This has prompted interest in the role of antioxidants, particularly the carotenoids lutein and zeaxanthin, in the prevention and treatment of this eye disease.

METHODS

The aim of this randomised controlled trial is to determine the effect of a nutritional supplement containing lutein, vitamins A, C and E, zinc, and copper on measures of visual function in people with and without age-related macular disease. Outcome measures are distance and near visual acuity, contrast sensitivity, colour vision, macular visual field, glare recovery, and fundus photography. Randomisation is achieved via a random number generator, and masking achieved by third party coding of the active and placebo containers. Data collection will take place at nine and 18 months, and statistical analysis will employ Student's t test.

DISCUSSION

A paucity of treatment modalities for age-related macular disease has prompted research into the development of prevention strategies. A positive effect on normals may be indicative of a role of nutritional supplementation in preventing or delaying onset of the condition. An observed benefit in the age-related macular disease group may indicate a potential role of supplementation in prevention of progression, or even a degree reversal of the visual effects caused by this condition.

How big is the burden of visual loss caused by age related macular degeneration in the United Kingdom?

AIMS

To predict the burden of blindness, partial sight, and visual impairment (binocular visual acuity 6/18 or less) due to late stage age related macular degeneration (AMD) in the ageing population of the United Kingdom.

METHODS

A systematic review, followed by a request for data, was used to establish a pooled prevalence of AMD and corresponding visual loss. Prevalence figures were applied to the UK population. Using UK population trends, the future burden of AMD over the coming decade was established.

RESULTS

Pooled data from six studies showed that the prevalence of visual loss caused by AMD increased exponentially from the age of 70-85 years of age, with 3.5% (95% CI 3.0 to 4.1) having visual impairment beyond the age of 75 years. The authors estimate that there are currently 214 000 (95% CI 151 000 to 310 000) with visual impairment caused by AMD (suitable for registration). This number is expected to increase to 239 000 (95% CI 168 000 to 346 000) by the year 2011. Currently there are 172 000 (95% CI 106 000 to 279 000) and 245 000 (95% CI 163 000 to 364 000) with geographical and neovascular AMD, respectively.

CONCLUSIONS

Estimates of visual impairment agree with official statistics for the number registered partially sighted or blind, caused by AMD, and are well below other figures often cited. Although these estimates are associated with wide confidence intervals (CI) and a number of caveats, they represent the best available data, which can be used to guide health and social care provision for older people in the UK setting. Implications for low vision services are outlined.

Risk, causes, and outcomes of visual impairment after loss of vision in the non-amblyopic eye: a population-based study

BACKGROUND

Screening for amblyopia in early childhood is done in many countries to ensure that affected children are detected and treated within the critical period, and achieve a level of vision in their amblyopic eye that would be useful should they lose vision in their non-amblyopic eye later in life. We aimed to investigate the risk, causes, and outcomes of visual impairment attributable to loss of vision in the non-amblyopic eye.

METHODS

For 24 months from July, 1997, national surveillance was done to identify all individuals in the UK with unilateral amblyopia (acuity worse than 6/12) who had newly acquired vision loss in the non-amblyopic eye, resulting in acuity of worse than 6/12 or visual-field restriction precluding driving. Information about participants was obtained at presentation and 1 year later. Participants were categorised as having socially significant visual impairment, or visual impairment, severe visual impairment, or blindness, in accordance with WHO taxonomy.

FINDINGS

Of 370 eligible individuals, at presentation 104 (28%) had socially significant visual impairment, 180 (49%) visual impairment, and 86 (23%) severe visual impairment or blindness. The minimum risk of permanent visual impairment by age 95 years was 32.9 (95% CI 29.1-36.9) per 100,000 total population. The projected lifetime risk of vision loss for an individual with amblyopia was at least 1.2% (95% CI 1.1-1.4). Only 36 (35%) of 102 people previously in paid employment were able to continue.

INTERPRETATION

In the UK, where screening for amblyopia is under review, risk of serious vision loss affecting the non-amblyopic eye and its results are greater than that previously assumed. Thus, in addition to the benefits of improved vision in the amblyopic eye, treatment of amblyopia during childhood is a potentially valuable strategy to prevent incapacitating vision loss later in life.

An update on photodynamic therapy in age-related macular degeneration

Age-related macular degeneration (AMD) is the leading cause of irreversible loss of central vision in people aged > 50 years in the western world. Until recently, the only proven treatment to reduce the risk of vision loss from its more severe neovascular form was laser photocoagulation, but this treatment was suitable for only 15% of cases. Photodynamic therapy (PDT) with verteporfin was recently proposed to be effective in reducing the risk of visual loss for an estimated 20 - 30% of neovascular AMD patients. This review covers AMD epidemiology, the mechanism of PDT, the 2-year results of the two major clinical studies of PDT with verteporfin, the cost-effectiveness of PDT and the current research status of other drugs for PDT in AMD.

Serum oxidative and antioxidant parameters in a group of Italian patients with age-related maculopathy

OBJECTIVES

The purpose of this study was to measure the oxidative and antioxidant biochemical parameters in the serum of Italian patients with age-related maculopathy (ARM) and in a similar age control group from the same area, in order to determine the weight of oxidative status as risk factor in the early stage of macular degeneration onwards.

DESIGN AND METHODS

Forty-eight ARM patients (19 early and 29 late form) and 46 normal subjects, similar for age, sex and life-style, were studied. A series of serum and/or plasma antioxidants (vitamins C, E, A, total and individual carotenoids, zinc, total plasma antioxidant capacity--TRAP) and oxidative parameters (reactive oxygen metabolites--ROM, oxidized-low-density lipoprotein antibodies-anti-Ox-LDL) were evaluated in both groups, also with regard to age and disease stage.

RESULTS

Levels of vitamins C, E, total carotenoids and beta-cryptoxanthine were lower in late ARM than in early ARM (p<0.05). Of the serum carotenoids investigated, only lycopene was lower in the two ARM forms than in controls (p<0.05). The main biochemical parameters, TRAP, zinc, anti-Ox-LDL and ROM were similar in the two groups.

CONCLUSIONS

A deficit of antioxidants (vitamins C, E and carotenoids) seems to be associated with ARM in Italian patients, particularly the advanced form, it is also suggested that in ARM patients macular susceptibility to oxidative damage is not related with age.

Gaining insight into age-related macular degeneration

PURPOSE/OBJECTIVE

To enhance nurse practitioner (NP) recognition of clients with age-related macular degeneration (AMD) based on history and physical examination findings, to encourage prompt initial referral of these clients to an ophthalmologist for a treatment evaluation, and to acquaint NPs with low vision rehabilitation services.

DATA SOURCES

Government documents, professional association practice guidelines, original research articles, journal articles, and Internet resources.

CONCLUSIONS

Age-related macular degeneration is a common, chronic vision-threatening condition necessitating prompt recognition and professional evaluation. If not recognized early, AMD can lead to low vision and a diminished quality of life for the elderly client.

IMPLICATIONS FOR PRACTICE

Even though NPs have a limited role in the treatment of AMD, they are in an instrumental position as a primary care providers to screen for this disease chiefly by: (a) adherence to eye examinations intervals, (b) recognition of risk factors, (c) use of the Amsler grid, (d) awareness of psychosocial dimensions, (e) making appropriate referrals, and (f) advocating low vision rehabilitation services.