Effects of black currant anthocyanins on intraocular pressure in healthy volunteers and patients with glaucoma

Optic Nerve Neuroprotection in Glaucoma: A Narrative Review

In recent years, researchers have been interested in neuroprotective therapies as a cutting-edge therapeutic strategy to treat neurodegenerative disorders by shielding the brain system from harmful events. Millions of individuals worldwide suffer from glaucoma, an ocular neurodegenerative disease characterized by gradual excavation of the optic nerve head, retinal axonal damage, and consequent visual loss. The pathology's molecular cause is still mostly unknown, and the current treatments are not able to alter the disease's natural progression. Thus, the modern approach to treating glaucoma consists of prescribing medications with neuroprotective properties, in line with the treatment strategy suggested for other neurodegenerative diseases. For this reason, several naturally derived compounds, including nicotinamide and citicoline, have been studied throughout time to try to improve glaucoma management by exploiting their neuroprotective properties. The purpose of this review is to examine the naturally derived compounds that are currently utilized in clinical practice for neuroprotection in glaucomatous patients based on scientific data, emphasizing these compounds' pivotal mechanism of action as well as their proven therapeutic and neuroprotective benefits.

Herbal and Natural Treatments for the Management of the Glaucoma: An Update

Glaucoma causes the degeneration of the retinal ganglion cells (RGCs) and their axons, inducing a tissue reshaping that affects both the retina and the optic nerve head. Glaucoma care especially focuses on reducing intraocular pressure, a significant risk factor for progressive damage to the optic nerve. The use of natural treatments, such as herbs, vitamins, and minerals, is becoming increasingly popular today. While plants are a rich source of novel biologically active compounds, only a small percentage of them have been phytochemically examined and evaluated for their medicinal potential. It is necessary for eye care professionals to inform their glaucoma patients about the therapy, protection, and efficacy of commonly used herbal medicines, considering the widespread use of herbal medicines. The purpose of this review is to examine evidence related to the most widely used herbal medicines for the management and treatment of glaucoma, to better understand the potential benefits of these natural compounds as supplementary therapy.

Evidence for Complementary and Alternative Therapies to Treat Glaucoma

Complementary and alternative medicine is used by approximately 5% of patients with glaucoma, and examples include marijuana, Ginkgo biloba extract, bilberry fruit extract, and acupuncture. Systemic marijuana is not beneficial for glaucoma due to the short duration of action, the lack of evidence that it alters disease progression, and its negative side effect profile. Drops that affect the cannabinoid pathway are still being studied. Ginkgo biloba and bilberry fruit extracts have been shown to decrease oxidative stress and improve perfusion of the optic nerve head. However, these findings are inconsistent throughout the literature and the studies are small, which makes the overall evidence weak. There is no evidence that acupuncture alters glaucoma disease progression or causes a sustained decrease in intraocular pressure. In summary, the literature suggests that there are transient and/or theoretical benefits of complementary and alternative medicine for glaucoma care; however, the overall evidence to support their use is weak.

Enzyme-assisted extraction of anthocyanins and other phenolic compounds from blackcurrant (Ribes nigrum L.) press cake: From processing to bioactivities

The effects of commercial enzymes (pectinases, cellulases, beta-1-3-glucanases, and pectin lyases) on the recovery of anthocyanins and polyphenols from blackcurrant press cake were studied considering two solid:solvent ratios (1:10 and 1:4 w/v). β-glucanase enabled the recovery of the highest total phenolic content - 1142 mg/100 g, and the extraction of anthocyanins was similar using all enzymes (∼400 mg/100 g). The use of cellulases and pectinases enhanced the extraction of antioxidants (DPPH - 1080 mg/100 g; CUPRAC - 3697 mg/100 g). The freeze-dried extracts presented antioxidant potential (CUPRAC, DPPH), which was associated with their biological effects in different systems: antiviral activity against both non-enveloped viruses (enterovirus coxsackievirus A-9) and enveloped coronaviruses (HCoV-OC43), and cytotoxicity towards cancer cells (A549 and HCT8). No cytotoxic effects on normal human lung fibroblast (IMR90) were observed, and no anti-inflammatory activity was detected in lipopolysaccharides-treated murine immortalised microglial cells.

Diet, Oxidative Stress, and Blood Serum Nutrients in Various Types of Glaucoma: A Systematic Review

Glaucoma is one of the most common causes of irreversible vision loss worldwide. It is an insidious disease with a multifactorial pathogenesis. Despite progress in treatment methods, prevention and lifestyle modifications may be useful in slowing the progression of this disease. This systematic review aimed to evaluate the influence of diet, oxidative stress, and disturbances in blood serum levels of nutrients on the incidence and severity of glaucoma based on scientific reports on the role of nutrition in the pathogenesis and course of glaucoma. This paper presents an analysis of the above issues; however, further research is required to develop this topic. Future clinical trials are needed to assess the influence of nutrition and to develop nutritional management strategies for patients with glaucoma.

Treatment of Glaucoma with Natural Products and Their Mechanism of Action: An Update

Glaucoma is one of the leading causes of irreversible blindness. It is generally caused by increased intraocular pressure, which results in damage of the optic nerve and retinal ganglion cells, ultimately leading to visual field dysfunction. However, even with the use of intraocular pressure-lowering eye drops, the disease still progresses in some patients. In addition to mechanical and vascular dysfunctions of the eye, oxidative stress, neuroinflammation and excitotoxicity have also been implicated in the pathogenesis of glaucoma. Hence, the use of natural products with antioxidant and anti-inflammatory properties may represent an alternative approach for glaucoma treatment. The present review highlights recent preclinical and clinical studies on various natural products shown to possess neuroprotective properties for retinal ganglion cells, which thereby may be effective in the treatment of glaucoma. Intraocular pressure can be reduced by baicalein, forskolin, marijuana, ginsenoside, resveratrol and hesperidin. Alternatively, Ginkgo biloba, Lycium barbarum, Diospyros kaki, Tripterygium wilfordii, saffron, curcumin, caffeine, anthocyanin, coenzyme Q10 and vitamins B3 and D have shown neuroprotective effects on retinal ganglion cells via various mechanisms, especially antioxidant, anti-inflammatory and anti-apoptosis mechanisms. Extensive studies are still required in the future to ensure natural products' efficacy and safety to serve as an alternative therapy for glaucoma.

Current situation and progress of drugs for reducing intraocular pressure

Glaucoma, the most common cause of irreversible blindness worldwide, usually causes characteristic optic nerve damage. Pathological intraocular pressure (IOP) elevation is a major risk factor. Drug reduction of IOP is the preferred treatment for clinicians because it can delay the progression of disease. However, the traditional IOP-lowering drugs currently used by patients may be poorly tolerated. Therefore, in recent years, some new drugs have been put into clinical application or in clinical phase I–III studies. They have a better IOP-lowering effect and fewer adverse reactions. Because glaucoma is a chronic disease, drugs need to be administered continuously for a long time. For patients, good compliance and high drug bioavailability have a positive effect on the prognosis of the disease. Therefore, clinicians and scientists have developed drug delivery systems to solve this complex problem. In addition, natural compounds and dietary supplements have a good effect of reducing IOP, and they can also protect the optic nerve through antioxidant action. We summarize the current traditional drugs, new drugs, sustained-release drug delivery systems, and complementary drugs and outline the mechanism of action and clinical effects of these drugs on glaucoma and their recent advances.

Non-drug interventions in glaucoma: Putative roles for lifestyle, diet and nutritional supplements

Glaucoma is a major ocular neurodegenerative disease characterized by progressive retinal ganglion cells degeneration and sight loss. Current treatment options have been limited to reducing intraocular pressure (IOP), known as the leading risk factor for this disease; however, glaucoma can develop even with low or normal IOP and progress despite controlling IOP values. Lifestyle, dietary habits, and supplementation may influence some of the risk factors and pathophysiological mechanisms underlying glaucoma development and progression; thus, the role of this complementary and alternative medicine in glaucoma has received great interest from both patients and ophthalmologists. We provide a summary of the current evidence concerning the relationship between lifestyle, dietary habits, and effects of supplements on the incidence and progression of glaucoma and their targets and associated mechanisms. The data suggest the existence of a therapeutic potential that needs to be further explored with both preclinical and rigorous clinical studies.

From Oxidative Stress to Inflammation in the Posterior Ocular Diseases: Diagnosis and Treatment

Most irreversible blindness observed with glaucoma and retina-related ocular diseases, including age-related macular degeneration and diabetic retinopathy, have their origin in the posterior segment of the eye, making their physiopathology both complex and interconnected. In addition to the age factor, these diseases share the same mechanism disorder based essentially on oxidative stress. In this context, the imbalance between the production of reactive oxygen species (ROS) mainly by mitochondria and their elimination by protective mechanisms leads to chronic inflammation. Oxidative stress and inflammation share a close pathophysiological process, appearing simultaneously and suggesting a relationship between both mechanisms. The biochemical end point of these two biological alarming systems is the release of different biomarkers that can be used in the diagnosis. Furthermore, oxidative stress, initiating in the vulnerable tissue of the posterior segment, is closely related to mitochondrial dysfunction, apoptosis, autophagy dysfunction, and inflammation, which are involved in each disease progression. In this review, we have analyzed (1) the oxidative stress and inflammatory processes in the back of the eye, (2) the importance of biomarkers, detected in systemic or ocular fluids, for the diagnosis of eye diseases based on recent studies, and (3) the treatment of posterior ocular diseases, based on long-term clinical studies.

Genus Ribes Linn. (Grossulariaceae): A comprehensive review of traditional uses, phytochemistry, pharmacology and clinical applications

ETHNOPHARMACOLOGICAL RELEVANCE

The genus Ribes Linn., which belongs to the Grossulariaceae family, contains 160 species distributed mainly in temperate and cold regions of the Northern Hemisphere. There are 59 species in southwest, northwest and northeast China. Some species of Ribes have been used as traditional and local medicines for the treatment of glaucoma, cardiovascular disease, stomachache, hepatitis, hyperlipidemia, hypertension and other ailments. However, the data provided in recent years have not been collated and compared.

AIM OF THE STUDY

This review aims to summarize the current status of ethnopharmacological uses, phytochemistry, pharmacology, clinical applications, and pharmacokinetics of the genus Ribes to better understand the therapeutic potential of the genus Ribes in the future and hope to provide a relatively novel perspective for further clinical application on the genus.

MATERIALS AND METHODS

The literature on Ribes was collected through a series of scientific search engines including Elsevier, ACS, Springer, Web of Science, PubMed, Google Scholar, Baidu Scholar, Wiley, China National Knowledge Infrastructure (CNKI) and books.

RESULTS

Ribes species have been used for detoxification, glaucoma, cardiovascular disease, stomachache, hepatitis, hyperlipidemia, hypertension and other ailments. These plants mainly contain phenolic glycosides, flavonoids, proanthocyanidins, polysaccharides, etc. Most traditional uses are related to biological activity and have been confirmed by modern research. Pharmacological studies in vitro and in vivo revealed that the extracts and pure compounds possessed significant hypolipidemic, antioxidant, anti-inflammatory, antitumor, antibacterial, and antiviral activity, eyesight protection and other effects.

CONCLUSIONS

The traditional uses, phytochemistry, pharmacology, pharmacokinetics, and clinical applications described in this article explained that the Ribes species has numerous activities, and these findings will promote further action in the area of mechanism research. However, very few preclinical and clinical studies have focused on the toxicology and pharmacokinetics of crude extracts and pure compounds from the genus Ribes. Moreover, several clinical evidence to support the health benefits of Ribes plants. The development of new medicines based on Ribes species as ingredients may be restricted. The pharmacological activity, clinical efficacy and safety of Ribes species need to be verified by systematic and comprehensive preclinical studies and clinical trials.

Anthocyanins: Promising Natural Products with Diverse Pharmacological Activities

Anthocyanins are natural products that give color to plants. As natural plant pigments, anthocyanins also have a series of health-promoting benefits. Many researchers have proved that anthocyanins have therapeutic effects on diseases, such as circulatory, nervous, endocrine, digestive, sensory, urinary and immune systems. Additionally, a large number of studies have reported that anthocyanins have an anticancer effect through a wide range of anti-inflammatory and antioxidant effects. The anti-disease impact and mechanism of anthocyanins are diverse, so they have high research value. This review summarizes the research progress of anthocyanins on the pharmacological agents of different diseases to provide references for subsequent research.

Searching for the Antioxidant, Anti-Inflammatory, and Neuroprotective Potential of Natural Food and Nutritional Supplements for Ocular Health in the Mediterranean Population

Adherence to a healthy diet offers a valuable intervention to compete against the increasing cases of ocular diseases worldwide, such as dry eye disorders, myopia progression, cataracts, glaucoma, diabetic retinopathy, or age macular degeneration. Certain amounts of micronutrients must be daily provided for proper functioning of the visual system, such as vitamins, carotenoids, trace metals and omega-3 fatty acids. Among natural foods, the following have to be considered for boosting eye/vision health: fish, meat, eggs, nuts, legumes, citrus fruits, nuts, leafy green vegetables, orange-colored fruits/vegetables, olives-olive oil, and dairy products. Nutritional supplements have received much attention as potential tools for managing chronic-degenerative ocular diseases. A systematic search of PubMed, Web of Science, hand-searched publications and historical archives were performed by the professionals involved in this study, to include peer-reviewed articles in which natural food, nutrient content, and its potential relationship with ocular health. Five ophthalmologists and two researchers collected the characteristics, quality and suitability of the above studies. Finally, 177 publications from 1983 to 2021 were enclosed, mainly related to natural food, Mediterranean diet (MedDiet) and nutraceutic supplementation. For the first time, original studies with broccoli and tigernut (chufa de Valencia) regarding the ocular surface dysfunction, macular degeneration, diabetic retinopathy and glaucoma were enclosed. These can add value to the diet, counteract nutritional defects, and help in the early stages, as well as in the course of ophthalmic pathologies. The main purpose of this review, enclosed in the Special Issue "Health Benefits and Nutritional Quality of Fruits, Nuts and Vegetables," is to identify directions for further research on the role of diet and nutrition in the eyes and vision, and the potential antioxidant, anti-inflammatory and neuroprotective effects of natural food (broccoli, saffron, tigernuts and walnuts), the Mediterranean Diet, and nutraceutic supplements that may supply a promising and highly affordable scenario for patients at risk of vision loss. This review work was designed and carried out by a multidisciplinary group involved in ophthalmology and ophthalmic research and especially in nutritional ophthalmology.

Effects of Flavonoid Supplementation on Common Eye Disorders: A Systematic Review and Meta-Analysis of Clinical Trials

Background: Emerging studies show that certain plant compounds may reduce the severity of most prevalent ocular abnormalities. The aim of this systematic review and meta-analysis was to assess the effect of dietary flavonoids on major eye disorders.

Methods: Eligible studies were identified by searching PubMed, Web of Science, Scopus, and Cochrane Library databases for all articles published up to April 2021. The literature search yielded 1,134 articles, and a total of 16 studies were included in the systematic review. A meta-analysis of 11 intervention trials involving a total of 724 participants was performed.

Results: Using a random-effects model, the pooled results revealed an overall significant effect of flavonoids on common ophthalmic disorders (standard mean difference = −0.39; 95% CI: −0.56, −0.21, p < 0.01). Of the subclasses of flavonoids, flavan-3-ols (standard mean difference = −0.62; 95% CI: −1.03, −0.22, p < 0.01), and anthocyanins (standard mean difference = −0.42; 95% CI: −0.63, −0.21, p < 0.01) were the only effective intervention for improving the outcomes of ocular conditions. For several of the other flavonoid subclasses, evidence on efficacy was insufficient.

Conclusion: Our findings indicate that flavonoids may improve the clinical manifestations associated with ocular disorders. However, further well-constructed clinical trials are required to confirm these results and examine the effect of flavonoids on eye disorders other than those identified in this review.

Systematic Review Registration: PROSPERO, identifier CRD42021247332.

Extraction, Identification, and Health Benefits of Anthocyanins in Blackcurrants (Ribes nigrum L.)

The fruit of the blackcurrant (Ribes nigrum L.) is round-shaped, dark purple, bittersweet, and seed-containing edible berries. The blackcurrant has been used as a traditional medicine in both Asia and European countries. It is known as a rich source of antioxidants, largely due to its high content of phenolic compounds, especially anthocyanins. Studies on anthocyanins from blackcurrants have adopted different extraction methods and a panel of anthocyanins has been identified in them. Research on the health benefits of blackcurrant anthocyanins has also grown. To present a general overview of research in blackcurrant anthocyanins, this review focuses on the extraction methods of anthocyanins from blackcurrants and the molecular mechanisms underlying their health benefits.

Glaucoma and Antioxidants: Review and Update

Glaucoma is a neurodegenerative disease characterised by the progressive degeneration of retinal ganglion cells. Oxidative stress has been related to the cell death in this disease. Theoretically, this deleterious consequence can be reduced by antioxidants substances. The aim of this review is to assemble the studies published in relation to antioxidant supplementation and its effects on glaucoma and to offer the reader an update on this field. With this purpose, we have included studies in animal models of glaucoma and clinical trials. Although there are variable results, supplementation with antioxidants in glaucoma may be a promising therapy in glaucoma.

Insights to potential antihypertensive activity of berry fruits

Hypertension is one of the main risk factors for cardiovascular disease and causes widespread morbidity and mortality worldwide. Although several antihypertensive drugs have been proposed for management of high blood pressure, changing lifestyle, including diet, has attracted interest recently. In this sense, consumption of fruits and vegetables, which are rich in vitamins, minerals, and phytochemicals, has been assigned as an efficient therapeutics. Berry fruits contain various bioactive compounds with potential health implications such as antioxidant, antimicrobial, anticancer, and anti-inflammatory properties. The main mechanisms responsible for antihypertensive activity mainly arise from the activity of flavonoids, minerals, and vitamins, as well as fibers. The objective of this review is to provide a summary of studies regarding the effect of berry fruits on the hypertensive animals and humans. The mechanisms involved in reducing blood pressure by each group of compounds have been highlighted. It can be concluded that berries' bioactive compounds are efficient in mitigation of hypertension through improvement of vascular function, angiotensin-converting enzyme's (ACE) inhibitory activity, increasing endothelial nitric oxide synthase (eNOS) activity, and nitric oxide (NO) production, besides anti-oxidative and anti-inflammatory activities. These fruits can be considered as potential sources of invaluable compounds for development of antihypertensive foods and pharmaceuticals.

Recent Research on the Health Benefits of Blueberries and Their Anthocyanins

Awareness of the human health benefits of blueberries is underpinned by a growing body of positive scientific evidence from human observational and clinical research, plus mechanistic research using animal and in vitro models. Blueberries contain a large number of phytochemicals, including abundant anthocyanin pigments. Of their various phytochemicals, anthocyanins probably make the greatest impact on blueberry health functionality. Epidemiological studies associate regular, moderate intake of blueberries and/or anthocyanins with reduced risk of cardiovascular disease, death, and type 2 diabetes, and with improved weight maintenance and neuroprotection. These findings are supported by biomarker-based evidence from human clinical studies. Among the more important healthful aspects of blueberries are their anti-inflammatory and antioxidant actions and their beneficial effects on vascular and glucoregulatory function. Blueberry phytochemicals may affect gastrointestinal microflora and contribute to host health. These aspects have implications in degenerative diseases and conditions as well as the aging process. More evidence, and particularly human clinical evidence, is needed to better understand the potential for anthocyanin-rich blueberries to benefit public health. However, it is widely agreed that the regular consumption of tasty, ripe blueberries can be unconditionally recommended.

Effects of Blackcurrant Anthocyanin on Endothelial Function and Peripheral Temperature in Young Smokers

Background: Blackcurrant anthocyanin (BCA) is expected to repair endothelial dysfunction, but it remains unclear whether beneficial effects are present in young healthy persons. This study examines whether supplements containing blackcurrant anthocyanin improve endothelial function and peripheral temperature in young smokers. Methods: Young, healthy male nonsmokers (N group: n = 11; mean age 22 ± 2 years) and smokers (S group: n = 13; mean age 21 ± 1 years) were enrolled. A randomized and double-blind trial was designed to compare the effects of no supplement, a supplement containing 50 mg of blackcurrant anthocyanin (supplement A), and a supplement containing 50 mg of blackcurrant anthocyanin plus vitamin E (supplement B) on flow-mediated dilatation (FMD) and skin temperature. Results: Under no supplement, FMD was unchanged during the 2 h period after smoking in the N group, whereas it was decreased during the 2 h period after smoking in the S group. Under the A supplement, FMD was decreased 1 h after smoking and returned to the baseline level 2 h after smoking in the S group. The skin temperature in the area of the foot dorsum was decreased in the S group after smoking compared with that in the N group, who did not smoke, whereas under A and B supplements, it was higher in the S group compared with that in the N group. Conclusions: BCA could attenuate the smoking-induced acute endothelial dysfunction and improve peripheral temperature in young smokers.

Effect of nutritional supplement based on melatonin on the intraocular pressure in normotensive subjects

PURPOSE

To evaluate the effect of a new nutritional supplement based on melatonin on the intraocular pressure (IOP) in normotensive subjects.

PATIENTS AND METHODS

A short-term prospective study was designed. Sixty-seven normotensive subjects were recruited. Patients were divided into two groups. The daily group (DG) (n = 18) was instructed to take the supplement between 22:00 and 23:00 (before sleeping) for 3 consecutive days. IOP was measured from 10.00 to 11.00 am the day before treatment and during the 3 days of experiment. The acute group (AG) (n = 49) was instructed to take the supplement after the second measure (11.00) of the second day. IOP was measured 1 h and just before the intake of the supplement and 1 and 2 h after. All measurements in this group were taken 1 day before without any supplement (control) and the day of experiment.

RESULTS

The DG group showed a significant decrease in IOP after supplement intake in all days of experiment, from 14.9 ± 3.4 mm Hg to 13.8 ± 2.9 mm Hg after 3 days of experiment (p value < 0.001). For AG, IOP did not change during the control day; however, a reduction of 1 mm Hg was found 2 and 3 h after supplement intake, from 15.7 ± 2.5 mm Hg to 14.7 ± 2.5 mm Hg and 15.1 ± 2.7 mm Hg, respectively, being statistically significant (p value < 0.001).

CONCLUSION

The supplement based on melatonin was able to reduce the IOP in normotensive subjects after 2 h of intake. Moreover, the daily intake showed a reduction in IOP during the 3 days of experiment.

Potential Factors Influencing the Effects of Anthocyanins on Blood Pressure Regulation in Humans: A Review

Dietary intake of anthocyanins (ACNs) is associated with a reduced risk of cardiovascular and coronary heart disease. While the anti-inflammatory, antioxidant, and lipid-lowering effects of ACN consumption have been consistently reported, their effect(s) on blood pressure regulation is less consistent and results from human studies are mixed. The objective of this review is attempting to identify potential patterns which may explain the variability in results related to blood pressure. To do so, we review 66 human intervention trials testing the effects on blood pressure of purified ACN or ACN-rich extracts, or whole berries, berry juices, powders, purees and whole phenolic extracts, from berries that are rich in ACN and have ACNs as predominant bioactives. Several factors appear to be involved on the mixed results reported. In particular, the baseline characteristics of the population in terms of blood pressure and total flavonoid intake, the dose and duration of the intervention, the differential effects of individual ACN and their synergistic effects with other phytochemicals, the ACN content and bioavailability from the food matrix, and individual differences in ACN absorption and metabolism related to genotype and microbiota enterotypes.

Cyanin Chloride Inhibits Hyperbaric Pressure-Induced Decrease of Intracellular Glutamate-Aspartate Transporter in Rat Retinal Müller Cells

Purpose

Glaucoma is the leading cause of irreversible blindness throughout the world. The pathogenesis of glaucoma is complex, and neuroprotection is a crucial aspect of therapy. High concentrations of extracellular glutamate are toxic to the optic nerve. The glutamate-aspartate transporter (GLAST) in retinal Müller cells is involved in the development of glaucoma. Anthocyanin has been reported to protect retinal neurons. We hypothesize that cyanin chloride, a type of anthocyanin, can inhibit hyperbaric pressure-induced GLAST decreases in cultured rat retinal Müller cells and may serve as a potential neuroprotective agent in glaucoma treatment.

Materials and Methods

Sprague Dawley rat Müller cells were cultured in a hyperbaric pressure device at 60 mmHg additional pressure and treated with cyanin chloride (10 μmol/L, 30 μmol/L, or 50 μmol/L) or vehicle for 2 hours. Cell survival rates (SRs) were evaluated by an MTT assay. GLAST mRNA and protein expression were determined by western blot and RT-PCR analyses, respectively.

Results

Cell SR was significantly decreased in the 60 mmHg additional hyperbaric pressure group compared to the control group (P < 0.01). Cyanin chloride treatment significantly improved SR under 60 mmHg additional pressure (P < 0.01). GLAST mRNA and protein expression levels in Müller cells were significantly reduced in the 60 mmHg hyperbaric pressure group compared to the control group (P < 0.01), but cyanin chloride significantly inhibited hyperbaric pressure-induced decreases in GLAST expression (P < 0.01).

Conclusion

Our results support our hypothesis and demonstrate that cyanin chloride can protect rat retinal Müller cells from hyperbaric pressure-induced decreases of GLAST.

Nutritional supplementation in the treatment of glaucoma: A systematic review

Current treatment strategies for glaucoma are limited to halting disease progression and do not restore lost visual function. Intraocular pressure is the main risk factor for glaucoma, and intraocular pressure-lowering treatment remains the mainstay of glaucoma treatment, but even successful intraocular pressure reduction does not stop the progression of glaucoma in all patients. We review the literature to determine whether nutritional interventions intended to prevent or delay the progression of glaucoma could prove to be a valuable addition to the mainstay of glaucoma therapy. A total of 33 intervention trials were included in this review, including 21 randomized controlled trials. These suggest that flavonoids exert a beneficial effect in glaucoma, particularly in terms of improving ocular blood flow and potentially slowing progression of visual field loss. In addition, supplements containing forskolin have consistently demonstrated the capacity to reduce intraocular pressure beyond the levels achieved with traditional therapy alone; however, despite the strong theoretical rationale and initial clinical evidence for the beneficial effect of dietary supplementation as an adjunct therapy for glaucoma, the evidence is not conclusive. More and better quality research is required to evaluate the role of nutritional supplementation in glaucoma.

The relation between dietary intake and glaucoma: a systematic review

PURPOSE

A common question of patients to their physician is what they can do themselves against glaucoma, except taking their daily medication. However, for ophthalmologists, it is often hard to give their patients an advice on their dietary intake. To help ophthalmologists in answering this question, an overview of the current scientific literature on the association of nutrients with glaucoma is presented.

METHODS

A comprehensive systematic review was conducted in which articles published up to September 2017 were identified in PubMed and reference lists. Nutrients were categorized into minerals and trace elements, nutrition with antioxidative properties and omega-fatty acids.

RESULTS

The literature search revealed a total of 407 articles of which a total of 46 met the inclusion criteria. Most of these articles studied the effect of nutrients on open-angle glaucoma. Many trace elements have been investigated in the literature, but the most interesting are selenium and iron (both may increase the risk of glaucoma). Investigated nutrients with antioxidative properties and omega-fatty acids included glutathione, nitric oxide, carotenoids, flavonoids, and omega-3 and omega-6 fatty acids. Of these, glutathione, nitric oxide, and flavonoids had a significant protective effect on glaucoma.

CONCLUSION

Intake of selenium and iron may increase the risk of glaucoma, though, only few studies have been done on this topic. Nitric oxide present in other dark green leafy vegetables seems to have a beneficial effect on glaucoma. However, the evidence for an association of dietary intake with glaucoma is still not strong. More (longitudinal and randomized clinical trials) studies are required to make the presented findings clinically applicable.

Effect of anthocyanin supplementation on cardio-metabolic biomarkers: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Several studies have shown effects of anthocyanin on blood pressure, blood glucose, and lipid profile in different conditions, but the results of these studies are controversial. We summarized evidence from randomized clinical trials (RCTs) that investigated the effects of anthocyanin supplementation on cardio-metabolic biomarkers in adults.

METHODS

The literature searches of MEDLINE and EMBASE for published studies in English was performed up to August 2017. Results were summarized as mean differences (MD) with 95% confidence intervals (CI). Effect sizes of eligible studies were pooled using random-effects models (the DerSimonian-Laird estimator). Heterogeneity among studies was evaluated by the Cochrane Q test.

RESULTS

Of 5370 papers, 19 RCTs met inclusion criteria. There was no significant effect of anthocyanin supplementation on weight, waist circumference (WC), body mass index (BMI), systolic and diastolic blood pressure (SBP and DBP). Our results indicated that anthocyanin supplementation had no significant effects on HbA1c (MD: -0.32; 95% CI = -0.64, 0.00; p = 0.050) with no heterogeneity (I² = 0.0%, p = 0.966, no significant heterogeneity), however anthocyanin supplementation had significant effect on HOMA-IR (MD: -0.21; 95% CI = -0.36, -0.07; p = 0.004) (I² = 37.9%, p = 0.200, no significant heterogeneity) in adults. Intake of anthocyanin had no significant effects on FBS (MD: 0.25; 95% CI = -5.70, 6.21; p = 0.933) and serum insulin (MD: 0.09; 95% CI = -0.92, 1.11; p = 0.860) with high heterogeneity for these variables (p = 0.000, and I² = 83.5%) and (p = 0.098, and I² = 52.4%), respectively. Anthocyanin supplementation had significant effects on total cholesterol (TC) and low density lipoprotein (LDL) for more than 300 mg/day intervention for more than 12 weeks. The dose and duration of supplementation were the potential sources of heterogeneity among most of the trials.

CONCLUSION

The results demonstrate that supplementation with anthocyanin have beneficial effect on HOMA-IR in adults.

Lifestyles guide and glaucoma (II). Diet, supplements, drugs, sleep, pregnancy, and systemic hypertension

PURPOSE

To establish evidence based guidelines to advise patients on the relationship between habits, diet, certain circumstances, diseases and glaucoma.

METHODS

Review of all published articles on glaucoma and sports or other activities. The papers were classified according to the level of scientific evidence based on the Oxford Centre for Evidence-based Medicine classification.

RESULTS

The evidence on the relationship between diet or supplements and the incidence or progression of glaucoma is insufficient to make a general recommendation for glaucoma patients. Although some studies on normal tension glaucoma suggest that Gingko biloba could reduce glaucoma progression, the results do not allow a general recommendation for all these patients. Similarly, the evidence on the usefulness of vitamin supplements is not conclusive. The studies on smoking do not clearly demonstrate the relationship between this habit and incidence of glaucoma. Marihuana is not a useful treatment for glaucoma. Although the results on the relationship between sleep apnoea and glaucoma are heterogeneous, it is recommended that patients with moderate to intense apnoea are tested for glaucoma. Pregnancy does not influence the course of the disease, but several hypotensive drugs may be harmful for the foetus. Nocturnal systemic hypotension is a risk factor for glaucoma progression.

CONCLUSIONS

Certain habits, circumstances, or diseases may have an influence on the onset or progression of glaucoma. It is important to have adequate information about the scientific evidence in the publications in order to properly advise patients.

Strategies to Reduce Oxidative Stress in Glaucoma Patients

BACKGROUND

Primary open-angle glaucoma (POAG) is a multifactorial pathology involving a variety of pathogenic mechanisms, including oxidative/nitrosative stress. This latter is the consequence of the imbalance between excessive formation and insufficient protection against reactive oxygen/nitrogen species.

OBJECTIVE

Our main goal is to gather molecular information to better managing pathologic variants that may determine the individual susceptibility to oxidative/nitrosative stress (OS/NS) and POAG.

METHOD

An extensive search of the scientific literature was conducted using PUBMED, the Web of Science, the Cochrane Library, and other references on the topic of POAG and OS/NS from human and animal model studies published between 2010 and 2017. Finally, 152 works containing relevant information that may help understanding the role of antioxidants, essential fatty acids, natural compounds and other similar strategies for counteracting OS/NS in POAG were considered.

RESULTS

A wide variety of studies have proven that antioxidants, among them vitamins B3, C and E, Coenzyme Q10 or melatonin, ω-3/ω-6 fatty acids and other natural compounds (such as coffee, green tea, bear bile, gingko biloba, coleus, tropical fruits, etc.,) may help regulating the intraocular pressure as well as protecting the retinal neurons against OS/NS in POAG.

CONCLUSION

Based on the impact of antioxidants and ω-3/ω-6 fatty acids at the molecular level in the glaucomatous anterior and posterior eye segments, further studies are needed by integrating all issues involved in glaucoma pathogenesis, endogenous and exogenous risk factors and their interactions that will allow us to reach newer effective biotherapies for preventing glaucomatous irreversible blindness.

Nutraceuticals for older people: facts, fictions and gaps in knowledge

In the last decades nutraceuticals have entered the health market as an easy and attractive means of preventing diseases. These products are of interest for an increasingly health-concerned society and may be especially relevant for preventing or delaying a number of age-related diseases, i.e. arthritis, cancer, metabolic and cardiovascular diseases, osteoporosis, cataracts, brain disorders, etc. Nutraceuticals are marketed in a variety of forms, composition and potential applications which have made their definition ambiguous and their use uncontrolled and poorly funded. Although epidemiological, animal and in vitro studies have given evidence of the potential benefits of some of these nutraceuticals or of their components, definitive proof of their effects in appropriate human clinical trials is still lacking in most cases, more critically among people above 65 years of age. We cover the well-established nutraceuticals (polyvitamins, omega-3 fatty acids, etc.) and will focus on many other 'novel' commercial nutraceuticals where the scientific evidence is more limited (food extracts, polyphenols, carotenoids, etc.). Solid scientific evidence has been reported only for a few nutraceuticals, which have some health claims approved by the European Food Safety Authority (EFSA). Further well-designed trials are needed to improve the current knowledge on the health benefits of nutraceuticals in the elderly. Overall, there are some facts, a lot of fiction and many gaps in the knowledge of nutraceutical benefits.