Ginkgo biloba extract for age-related macular degeneration

Health Benefits of Polyphenols and Carotenoids in Age-Related Eye Diseases

Oxidative stress and inflammation play a critical role in the initiation and progression of age-related ocular abnormalities as cataract, glaucoma, diabetic retinopathy, and macular degeneration. Therefore, phytochemicals with proven antioxidant and anti-inflammatory activities, such as carotenoids and polyphenols, could be of benefit in these diseases. We searched PubMed and Web of Science databases for original studies investigating the benefits of different carotenoids and polyphenols in age-related ophthalmic diseases. Our results showed that several polyphenols (such as anthocyanins, Ginkgo biloba, quercetin, and resveratrol) and carotenoids (such as lutein, zeaxanthin, and mezoxanthin) have shown significant preventive and therapeutic benefits against the aforementioned conditions. The involved mechanisms in these findings include mitigating the production of reactive oxygen species, inhibiting the tumor necrosis factor-α and vascular endothelial growth factor pathways, suppressing p53-dependent apoptosis, and suppressing the production of inflammatory markers, such as interleukin- (IL-) 8, IL-6, IL-1a, and endothelial leucocyte adhesion molecule-1. Consumption of products containing these phytochemicals may be protective against these diseases; however, adequate human data are lacking. This review discusses the role and mechanisms of polyphenols and carotenoids and their possible synergistic effects on the prevention and treatment of age-related eye diseases that are induced or augmented by oxidative stress and inflammation.

The treatment methods for post-stroke visual impairment: A systematic review

AIM

To provide a systematic overview of interventions for stroke related visual impairments.

METHOD

A systematic review of the literature was conducted including randomized controlled trials, controlled trials, cohort studies, observational studies, systematic reviews, and retrospective medical note reviews. All languages were included and translation obtained. This review covers adult participants (aged 18 years or over) diagnosed with a visual impairment as a direct cause of a stroke. Studies which included mixed populations were included if over 50% of the participants had a diagnosis of stroke and were discussed separately. We searched scholarly online resources and hand searched articles and registers of published, unpublished, and ongoing trials. Search terms included a variety of MESH terms and alternatives in relation to stroke and visual conditions. Article selection was performed by two authors independently. Data were extracted by one author and verified by a second. The quality of the evidence and risk of bias was assessed using appropriate tools dependant on the type of article.

RESULTS

Forty-nine articles (4142 subjects) were included in the review, including an overview of four Cochrane systematic reviews. Interventions appraised included those for visual field loss, ocular motility deficits, reduced central vision, and visual perceptual deficits.

CONCLUSION

Further high quality randomized controlled trials are required to determine the effectiveness of interventions for treating post-stroke visual impairments. For interventions which are used in practice but do not yet have an evidence base in the literature, it is imperative that these treatments be addressed and evaluated in future studies.

Ginkgo biloba extract for age-related macular degeneration

BACKGROUND

Ginkgo is used in the treatment of peripheral vascular disease and 'cerebral insufficiency'. It is thought to have several potential mechanisms of action including increased blood flow, platelet activating factor antagonism, and prevention of membrane damage caused by free radicals. Vascular factors and oxidative damage are thought to be two potential mechanisms in the pathology of age-related macular degeneration (AMD).

OBJECTIVES

The objective of this review was to determine the effect of Ginkgo biloba extract on the progression of AMD.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2012, Issue 10), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to October 2012), EMBASE (January 1980 to October 2012), Allied and Complementary Medicine Database (AMED) (January 1985 to October 2012), OpenGrey (System for Information on Grey Literature in Europe) (www.opengrey.eu/), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 5 October 2012. We searched the reference lists of identified reports and the Science Citation Index. We also contacted investigators of included studies for additional information.

SELECTION CRITERIA

All randomised trials in people with AMD where Ginkgo biloba extract had been compared to control were included.

DATA COLLECTION AND ANALYSIS

The review author extracted data using a standardised form. The data were verified with the trial investigators. Trial quality was assessed.

MAIN RESULTS

Two published trials were identified that randomised a total of 119 people. In one study conducted in France, 20 people were randomly allocated to Gingko biloba extract EGb 761 80 mg twice daily or placebo. In the other study conducted in Germany, 99 people were randomly allocated to two different doses of Ginkgo biloba extract EGb 761 (240 mg per day and 60 mg per day). Treatment duration in both studies was six months. Both trials reported some positive effects of Ginkgo biloba on vision however their results could not be pooled. Adverse effects and quality of life for people with AMD were not reported.

AUTHORS' CONCLUSIONS

The question as to whether people with AMD should take Ginkgo biloba extract to prevent progression of the disease has not been answered by research to date. Two small trials have suggested possible benefit of Gingko biloba on vision and further trials are warranted. Ginkgo biloba is widely used in China, Germany, and France. Future trials should be larger, and last longer, in order to provide a more robust measure of the effect of Gingko biloba extract on AMD.

Interventions for age-related visual problems in patients with stroke

BACKGROUND

The prevalence of eye problems increases with age and, consequently, so does the level of visual impairment. As the incidence of stroke also increases with age, a significant proportion of stroke patients will have age-related visual problems. It is possible that the effect of interventions for age-related visual problems may differ in the population of stroke patients compared to the wider population of older people. The interaction between the problems arising directly from stroke and those arising directly from age-related visual problems will be complex. Interventions for age-related visual problems may also be affected by the presence of other stroke-related co-morbidities. Consequently, the nature and outcome of interventions for age-related visual problems may be different in patients with stroke.

OBJECTIVES

The aim of this review is to determine if interventions for age-related visual problems improve functional ability following stroke.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (March 2011), the Cochrane Eyes and Vision Group Trials Register (December 2009) and nine electronic bibliographic databases including: the Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 1), MEDLINE (1950 to February 2011), EMBASE (1980 to February 2011), CINAHL (1982 to February 2011), AMED (1985 to February 2011) and PsycINFO (1967 to February 2011). We also searched reference lists and trials registers, handsearched journals and conference proceedings, and contacted experts.

SELECTION CRITERIA

Randomised trials in adults after stroke, where the intervention is specifically targeted at assessing, treating or correcting age-related visual problems, or improving the ability of the patient to cope with visual impairment. Primary outcome was functional ability in activities of daily living and secondary outcomes included functional ability in extended activities of daily living, visual acuity, visual field, visual function, balance, falls, depression and anxiety, discharge destination/residence after stroke, quality of life and social isolation, adverse events and death.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened abstracts and planned to extract data and appraise trials. We planned that assessment of methodological quality would be undertaken for allocation concealment, blinding of outcome assessor, method of dealing with missing data and other potential sources of bias.

MAIN RESULTS

We considered 7357 titles, 460 abstracts and 85 full papers. We identified no studies for inclusion in this review.

AUTHORS' CONCLUSIONS

There are no implications for practice arising from this review. Evidence relating to the management of patients (from the general population) with age-related visual problems is available from other Cochrane reviews and is likely to be the best evidence available for making treatment decisions about individual patients. Subgroup analyses within these reviews to explore the effect of interventions for age-related visual problems in patients with stroke are recommended. We recommend that the objectives and selection criteria for this Cochrane review are amended and clarified prior to any future updates.

Cochrane systematic reviews of Chinese herbal medicines: an overview

OBJECTIVES

our study had two objectives: a) to systematically identify all existing systematic reviews of Chinese herbal medicines (CHM) published in Cochrane Library; b) to assess the methodological quality of included reviews.

METHODOLOGY/PRINCIPAL FINDINGS

We performed a systematic search of the Cochrane Database of Systematic Reviews (CDSR, Issue 5, 2010) to identify all reviews of CHM. A total of fifty-eight reviews were eligible for our study. Twenty-one of the included reviews had at least one Traditional Chinese Medicine (TCM) practitioner as its co-author. 7 reviews didn't include any primary study, the remaining reviews (n = 51) included a median of 9 studies and 936 participants. 50% of reviews were last assessed as up-to-date prior to 2008. The questions addressed by 39 reviews were broad in scope, in which 9 reviews combined studies with different herbal medicines. For OQAQ, the mean of overall quality score (item 10) was 5.05 (95% CI; 4.58-5.52). All reviews assessed the methodological quality of primary studies, 16% of included primary studies used adequate sequence generation and 7% used adequate allocation concealment. Of the 51 nonempty reviews, 23 reviews were reported as being inconclusive, while 27 concluded that there might be benefit of CHM, which was limited by the poor quality or inadequate quantity of included studies. 58 reviews reported searching a median of seven electronic databases, while 10 reviews did not search any Chinese database.

CONCLUSIONS

Now CDSR has included large numbers of CHM reviews, our study identified some areas which could be improved, such as almost half of included reviews did not have the participation of TCM practitioners and were not up-to-date according to Cochrane criteria, some reviews pooled the results of different herbal medicines and ignored the searching of Chinese databases.

Evidence from the Cochrane Collaboration for Traditional Chinese Medicine therapies

BACKGROUND

The Cochrane Collaboration, an international not-for-profit organization that prepares and maintains systematic reviews of randomized trials of health care therapies, has produced reviews summarizing much of the evidence on Traditional Chinese Medicine (TCM). Our objective was to review the evidence base according to Cochrane systematic reviews.

METHODS

In order to detect reviews focusing on TCM, we searched the titles and abstracts of all reviews in Issue 4, 2008 of the Cochrane Database of Systematic Reviews. For each review, we extracted data on the number of trials included and the total number of participants. We provided an indication of the strength of the review findings by assessing the reviewers' abstract conclusions statement. We supplemented our assessment of the abstract conclusions statements with a listing of the comparisons and outcomes showing statistically significant meta-analyses results.

RESULTS

We identified 70 Cochrane systematic reviews of TCM, primarily acupuncture (n = 26) and Chinese herbal medicine (n = 42), and 1 each of moxibustion and t'ai chi. Nineteen (19) of 26 acupuncture reviews and 22/42 herbal medicine reviews concluded that there was not enough good quality trial evidence to make any conclusion about the efficacy of the evaluated treatment, while the remaining 7 acupuncture and 20 herbal medicine reviews and each of the moxibustion and t'ai chi reviews indicated a suggestion of benefit, which was qualified by a caveat about the poor quality and quantity of studies. Most reviews included many distinct interventions, controls, outcomes, and populations, and a large number of different comparisons were made, each with a distinct forest plot.

CONCLUSIONS

Most Cochrane systematic reviews of TCM are inconclusive, due specifically to the poor methodology and heterogeneity of the studies reviewed. Some systematic reviews provide preliminary evidence of Chinese medicine's benefits to certain patient populations, underscoring the importance and appropriateness of further research. These preliminary findings should be considered tentative and need to be confirmed with rigorous randomized controlled trials.

Wound healing in radiated skin: pathophysiology and treatment options

Ulcers in radiated skin continue to be a challenge for health care practitioners. Healing impairment in the setting of radiation-damaged tissue will most of the time lead to chronic wounds that reduce the patient's quality of life. In this review, we present an update of the pathophysiology of tissue damage caused by radiation that leads to chronic ulceration. We also explore the evidence available on the different prevention and treatment modalities that have been reported in the literature. The evidence for most preventive measures is inconclusive; however, sucralfate and amifostine seem to be the adequate recommendations for prophylaxis. As for treatment of ulcerated patients, the strongest level of evidence found was for the use of pentoxifylline, but proper trials are still scarce to be considered standard adjuvant therapy. Hyperbaric oxygen, cytokines and other growth factors and surgical interventions have shown some benefit in case reports and case series only. Other therapies show promise based on their mechanism of action but need to be tested in human studies and clinical trials.

Supplements and age-related eye conditions the beaver dam eye study

OBJECTIVE

To investigate the association of use of vitamin, mineral, and nonvitamin nonmineral supplements with common age-related eye diseases.

DESIGN

Population-based prospective study with incidence data.

PARTICIPANTS

Subjects were participants in the Beaver Dam Eye Study who contributed data in 1988 to 1990 (n = 4926), 1993 to 1995 (n = 3722), 1998 to 2000 (n = 2962), and 2003 to 2005 (n = 2375).

METHODS

Use of all medications and supplements were collected from study participants at each of 4 examinations. Intraocular pressure (IOP) measurement and fundus and lens photography were done at each visit. Visual field data are available only from baseline. Photographs of the lenses, retina, and discs were graded using standard protocols by trained graders.

MAIN OUTCOME MEASURES

Incidence of age-related cataracts, macular degeneration (AMD), and high IOP for one set of analyses and incidence of supplement use for the second set of analyses.

RESULTS

There was little evidence of any significant associations between supplement use and incident ocular outcomes except for a small protective effect for cortical cataracts by vitamins A and D, zinc, and multivitamins and increased odds of late AMD. Late AMD was associated with incident use of vitamins A, C, and E and zinc.

CONCLUSIONS

Age-related macular degeneration seems to precede use of vitamins A, C, and E and zinc. This may reflect advice by family, friends, and health care providers about the benefits of Age-Related Eye Disease Study-like supplements.

Surgical implantation of steroids with antiangiogenic characteristics for treating neovascular age-related macular degeneration

BACKGROUND

Neovascular age-related macular degeneration (AMD) is associated with rapid vision loss due to choroidal neovascularization (CNV), leakage, and scarring. Steroids have gained attention in their role for the treatment of neovascular AMD for their antiangiogenic and anti-inflammatory properties.

OBJECTIVES

This review aims to examine effects of steroids with antiangiogenic properties in the treatment of neovascular AMD.

SEARCH STRATEGY

We searched for trials in CENTRAL, MEDLINE, EMBASE, and LILACS on 2 October 2006.

SELECTION CRITERIA

We included randomised controlled clinical trials of intra- and peri-ocular steroids in people diagnosed with neovascular AMD.

DATA COLLECTION AND ANALYSIS

Review authors extracted the data and assessed trial quality independently. We did not pool data since the included studies evaluated difference comparisons.

MAIN RESULTS

We report the risk of losing three or more lines vision at 12 months - "vision loss". One trial (139 people randomized) reported that a single dose of intravitreal triamcinolone (n = 75) (4 mg) had no significant effect on the risk of vision loss compared to placebo (n = 76). (Risk ratio vision loss 0.97, 95% confidence interval (CI) 0.74 to 1.26). Eyes treated with triamcinolone were more likely to develop cataracts and experience increased intraocular pressure (IOP) compared to untreated eyes. One trial (128 people randomized) reported the effects of anecortave acetate (3 mg (n = 32), 15 mg (n = 33) or 30 mg (n = 33) single dose with retreatment every six months if indicated) compared to placebo (n = 30). Risk ratio vision loss 0.80 (95% CI 0.45 to 1.45) in the 3 mg group, 0.45 (95% CI 0.21 to 0.97) in the 15 mg group and 0.91 (95% CI 0.52 to 1.58) in the 30 mg group. Side effects were similar in all treatment groups with the anecortave group having a slightly higher incidence of foreign body sensation compared to placebo. There was a high loss to follow-up. The final analysis may have been subject to selection bias as participants who were not selected for retreatment, possibly with worsening disease, were excluded. There was also a possibility of type I error due to multiple statistical comparisons. The sample size was estimated on the basis of a single 2-way comparison but three 2-way comparisons were analysed and presented. One trial reported that anecortave acetate (n = 263) (15 mg administered at beginning of study and six months) gave similar results to photodynamic therapy (n = 267) (risk ratio vision loss 1.08, 95% CI 0.91 to 1.29).

AUTHORS' CONCLUSIONS

Overall there is weak evidence as to the benefits and harms of steroids with antiangiogenic properties for treating neovascular AMD with only three published trials of variable quality. Intravitreal triamcinolone injection for neovascular AMD does not appear to prevent severe vision loss and is associated with increased IOP and higher risk of cataract formation. Anecortave acetate 15 mg may have a mild benefit in stabilizing vision, but further better quality evidence is needed. The role of steroids in combination with other treatment modalities is yet to be determined.

Systematic reviews of complementary therapies - an annotated bibliography. Part 2: herbal medicine

BACKGROUND

Complementary therapies are widespread but controversial. We aim to provide a comprehensive collection and a summary of systematic reviews of clinical trials in three major complementary therapies (acupuncture, herbal medicine, homeopathy). This article is dealing with herbal medicine. Potentially relevant reviews were searched through the register of the Cochrane Complementary Medicine Field, the Cochrane Library, Medline, and bibliographies of articles and books. To be included articles had to review prospective clinical trials of herbal medicines; had to describe review methods explicitly; had to be published; and had to focus on treatment effects. Information on conditions, interventions, methods, results and conclusions was extracted using a pre-tested form and summarized descriptively.

RESULTS

From a total of 79 potentially relevant reviews pre-selected in the screening process 58 met the inclusion criteria. Thirty of the reports reviewed ginkgo (for dementia, intermittent claudication, tinnitus, and macular degeneration), hypericum (for depression) or garlic preparations (for cardiovascular risk factors and lower limb atherosclerosis). The quality of primary studies was criticized in the majority of the reviews. Most reviews judged the available evidence as promising but definitive conclusions were rarely possible.

CONCLUSIONS

Systematic reviews are available on a broad range of herbal preparations prescribed for defined conditions. There is very little evidence on the effectiveness of herbalism as practised by specialist herbalists who combine herbs and use unconventional diagnosis.