Nutritional and medical food therapies for diabetic retinopathy

Dissecting hair breakage in alopecia areata: the central role of dysregulated cysteine homeostasis

In the initial stages of Alopecia Areata (AA), the predominance of hair breakage or exclamation mark hairs serves as vital indicators of disease activity. These signs are non-invasive and are commonly employed in dermatoscopic examinations. Despite their clinical salience, the underlying etiology precipitating this hair breakage remains largely uncharted territory. Our exhaustive review of the existing literature points to a pivotal role for cysteine-a key amino acid central to hair growth-in these mechanisms. This review will probe and deliberate upon the implications of aberrant cysteine metabolism in the pathogenesis of AA. It will examine the potential intersections of cysteine metabolism with autophagy, ferroptosis, immunity, and psychiatric manifestations associated with AA. Such exploration could illuminate new facets of the disease's pathophysiology, potentially paving the way for innovative therapeutic strategies.

Effect of High-Sucrose Diet on the Occurrence and Progression of Diabetic Retinopathy and Dietary Modification Strategies

As the most serious of the many worse new pathological changes caused by diabetes, there are many risk factors for the occurrence and development of diabetic retinopathy (DR). They mainly include hyperglycemia, hypertension, hyperlipidemia and so on. Among them, hyperglycemia is the most critical cause, and plays a vital role in the pathological changes of DR. High-sucrose diets (HSDs) lead to elevated blood glucose levels in vivo, which, through oxidative stress, inflammation, the production of advanced glycation end products (AGEs) and vascular endothelial growth factor (VEGF), cause plenty of pathological damages to the retina and ultimately bring about loss of vision. The existing therapies for DR primarily target the terminal stage of the disease, when irreversible visual impairment has appeared. Therefore, early prevention is particularly critical. The early prevention of DR-related vision loss requires adjustments to dietary habits, mainly by reducing sugar intake. This article primarily discusses the risk factors, pathophysiological processes and molecular mechanisms associated with the development of DR caused by HSDs. It aims to raise awareness of the crucial role of diet in the occurrence and progression of DR, promote timely changes in dietary habits, prevent vision loss and improve the quality of life. The aim is to make people aware of the importance of diet in the occurrence and progression of DR. According to the dietary modification strategies that we give, patients can change their poor eating habits in a timely manner to avoid theoretically avoidable retinopathy and obtain an excellent prognosis.

Recent advances in the treatment and delivery system of diabetic retinopathy

Diabetic retinopathy (DR) is a highly tissue-specific neurovascular complication of type 1 and type 2 diabetes mellitus and is among the leading causes of blindness worldwide. Pathophysiological changes in DR encompass neurodegeneration, inflammation, and oxidative stress. Current treatments for DR, including anti-vascular endothelial growth factor, steroids, laser photocoagulation, and vitrectomy have limitations and adverse reactions, necessitating the exploration of novel treatment strategies. This review aims to summarize the current pathophysiology, therapeutic approaches, and available drug-delivery methods for treating DR, and discuss their respective development potentials. Recent research indicates the efficacy of novel receptor inhibitors and agonists, such as aldose reductase inhibitors, angiotensin-converting enzyme inhibitors, peroxisome proliferator-activated receptor alpha agonists, and novel drugs in delaying DR. Furthermore, with continuous advancements in nanotechnology, a new form of drug delivery has been developed that can address certain limitations of clinical drug therapy, such as low solubility and poor penetration. This review serves as a theoretical foundation for future research on DR treatment. While highlighting promising therapeutic targets, it underscores the need for continuous exploration to enhance our understanding of DR pathogenesis. The limitations of current treatments and the potential for future advancements emphasize the importance of ongoing research in this field.

Enhanced systematic delivery of fluconazole-loaded biotin-glutathione functionalized chitosan-g-proline carrier into the infected retinitis treatment

BACKGROUND

The polymer-based facile and effective drug carrier approach was developed to treat superficial fungal infected retinopathy infections.

METHODS

Here, biotin-glutathione (B-GHS) functionalized with chitosan grafted proline (CS-g-P) moieties were fabricated with the loading of fluconazole (FLZ) for the treatment of retinopathy. FT-IR and XRD techniques were used to characterize chemical structural and phase changes of the prepared carriers The SEM results show that the sphere morphology with interconnection particle nature.

RESULTS

The particle diameter was found as ~ 6.5 and ~ 8.6 nm for CS-g-P/B-GHS and FLZ-loaded CS-g-P/B-GHS carriers, respectively. The negative surface charge was found as the values of CS-g-P/B-GHS and FLZ-loaded CS-g-P/B-GHS, such as -20.7 mV and - 32.2 mV, from zeta potential analysis. The in-vitro FLZ releases from the CS-g-P/B-GHS were investigated at pH 7.4 (PBS) as the tear fluid environment, and it was observed at 85.02% of FLZ release in 8 h reaction time. The sustained release was observed, leading to the necessity for prolonged therapeutic effects. The antifungal effect of the carrier was studied by the minimum inhibitory concentration (MIC) and the percentage inhibition of viable fungal count against Candida albicans, and it observed 81.02% of the zone of inhibition by the FLZ carrier.

CONCLUSION

FLZ-loaded CS-g-P/B-GHS carrier could inhibit the biofilm formation in a concentration-dependent inhibition. Hence, A novel FLZ/B-GHS-CS-g-P carrier is a hopeful approach for effectively treating superficial fungal contaminations of the retina region.

Association of vitamin B6 intake with the risk and prognosis of diabetic retinopathy: a NHANES-based study

CLINICAL RELEVANCE

Investigating the role of dietary vitamin B6 intake in the risk and prognosis of diabetic retinopathy (DR) could facilitate the management of DR.

BACKGROUND

This study aimed to assess the association between dietary vitamin B6 intake and the risk of DR and further explore the association between vitamin B6 intake and mortality in patients with DR.

METHODS

This retrospective cohort study gained data from the National Health and Nutrition Examination Survey (NHANES) 2005-2006 and 2007-2008. The intake of dietary vitamin B6 was assessed by two 24-h dietary recall interviews. Mortality information in the National Death Index was recorded from the date of survey participation through 31 December 2019. Multivariate regression analyses were employed to assess the association between vitamin B6 intake and the risk of DR, and the association between vitamin B6 intake and the risk of mortality in patients with DR.

RESULTS

A total of 5559 subjects were included, of which 693 (12.47%) had DR. Among these patients with DR, 429 (61.90%) were survivors. Multivariate analyses showed that the intake of vitamin B6 was negatively associated with the risk of DR (odds ratio = 0.81, 95% confidence level: 0.69-0.95, p = 0.012), and patients with DR with an increased intake of vitamin B6 had a significantly decreased risk of all-cause death (hazard ratio = 0.81, 95% confidence level: 0.66-0.99, p = 0.041) or cardiovascular disease-related death (hazard ratio = 0.76, 95% confidence level: 0.58-0.98, p = 0.037).

CONCLUSION

The intake of vitamin B6 was negatively associated with the risk of DR, and in patients with DR, a higher intake of vitamin B6 was associated with a lower risk of all-cause death and cardiovascular disease-related death, indicating the possible protective role of increased vitamin B6 intake.

Complementary Approaches to Retinal Health Focusing on Diabetic Retinopathy

Diabetes mellitus affects carbohydrate homeostasis but also influences fat and protein metabolism. Due to ophthalmic complications, it is a leading cause of blindness worldwide. The molecular pathology reveals that nuclear factor kappa B (NFκB) has a central role in the progression of diabetic retinopathy, sharing this signaling pathway with another major retinal disorder, glaucoma. Therefore, new therapeutic approaches can be elaborated to decelerate the ever-emerging "epidemics" of diabetic retinopathy and glaucoma targeting this critical node. In our review, we emphasize the role of an improvement of lifestyle in its prevention as well as the use of phytomedicals associated with evidence-based protocols. A balanced personalized therapy requires an integrative approach to be more successful for prevention and early treatment.

Neuroprotective role of plumbagin on eye damage induced by high-sucrose diet in adult fruit fly Drosophila melanogaster

The natural compound plumbagin has a wide range of pharmacological and potential therapeutic activities, although its role in neuroretina degeneration is unknown. Here we evaluated the effects of plumbagin on retina homeostasis of the fruit fly Drosophila melanogaster fed with high glucose diet, a model of hyperglycemia-induced eye impairment to study the pathophysiology of diabetic retinopathy at the early stages. To this aim, the visual system of flies orally administered with plumbagin has been analyzed at structural, functional, and molecular/cellular level as for instance neuronal apoptosis/autophagy dysregulation and oxidative stress-related signals. Our results demonstrated that plumbagin ameliorates the visual performance of hyperglycemic flies. Drosophila eye-structure, clearly altered by hyperglycemia, i.e. defects of the pattern of ommatidia, irregular rhabdomeres, vacuoles, damaged mitochondria, and abnormal phototransduction units were rescued, at least in part, by plumbagin. In addition, it reactivated autophagy, decreased the presence of cell death/apoptotic features, and exerted antioxidant effects in the retina. In terms of mechanisms favoring death/survival ratio, Nrf2 signaling activation may be one of the strategies by which plumbagin reduced redox unbalance mainly increasing the levels of glutathione-S-transferase. Likewise, plumbagin may act additively and/or synergistically inhibiting the mitochondrial-endoplasmic reticulum stress and unfolded protein response pathways, which prevented neuronal impairment and eye damage induced by reactive oxygen species. These results provide an avenue for further studies, which may be helpful to develop novel therapeutic candidates and drug targets against eye neurotoxicity by high glucose, a key aspect in retinal complications of diabetes.

Dietary micronutrient adequacies and adherence to the Mediterranean diet in a population of older adults with type 2 diabetes: A cross-sectional study

BACKGROUND AND AIMS

There are few data on micronutrient intake in older adults with type 2 diabetes (T2D) and their adherence to the Mediterranean diet, a dietary pattern rich in micronutrients. In this cross-sectional study, we evaluated the prevalence of adequacy in micronutrient intake according to the recommendations, and the adherence to the Mediterranean diet in older adults with T2D.

METHODS

One hundred thirty-eight patients (47 women and 91 men) with T2D aged over 65 years were included. Dietary habits were assessed by three 24-h dietary recalls. The micronutrient intake, expressed as mean daily intake, and adequacy were compared with the dietary recommendations proposed by the Italian Society of Human Nutrition (LARN) and the European Food Safety Agency (EFSA). Adherence to the Mediterranean diet was evaluated by the MEDI-quest score.

RESULTS

An extremely low proportion of participants (∼1%) adhered to the recommendations for potassium and vitamin D intake. A low proportion of participants adhered to the recommendations for calcium (∼23%), magnesium (∼16%), selenium (∼17%), vitamin E (∼14%), riboflavin (∼28%), vitamin B6 (∼29%), folate (∼25%), and niacin (∼27%) intake. More than 60% of the population adhered to the recommendations for iron, copper, vitamin A and B12 intake. Only 53% of the population showed high adherence to the Mediterranean diet.

CONCLUSIONS

Our data indicate that a very low proportion of older adults with T2D meet the recommendations for ten micronutrients (calcium, potassium, magnesium, selenium, vitamin D, vitamin E, riboflavin, vitamin B6, folate, and niacin) with an unsatisfactory adherence to the Mediterranean diet. Nutritional approaches aimed at favoring adherence to dietary recommendations and increasing the consumption of foods rich in micronutrients should be implemented in older adults.

Oxidative Stress and Antioxidant-Based Interventional Medicine in Ophthalmology

The different anatomical compartments of the eye are highly subjected to reactive oxygen species (ROS) generation due to internal factors, such as metabolic high oxygen consumption, as well as environmental factors, including UV light. An antioxidant defense system is endowed in the eye tissues to regulate ROS quantity and activity. When this homeostatic system is overwhelmed, oxidative stress occurs, causing cellular damage, chronic inflammation, and tissue degeneration. It also plays a significant role in the development and progression of various ocular diseases. Understanding the mechanisms underlying oxidative stress in ocular conditions is thus crucial for the development of effective prevention and treatment strategies. To track marketed products based on antioxidant substances as active ingredients, the databases of the European Medicines Agency and the U.S. Food and Drug Administration were consulted. Only a limited number of items were identified, which were either used as therapeutic treatment or during ocular surgery, including antioxidants, synthetical derivatives, or pro-drugs designed to enhance tissue permeation and activity. This review aims to provide an overview of the primary ocular pathologies associated with oxidative stress and of the available pharmacological interventions centered around antioxidant molecules. Such insights are essential for advancing the development of effective prevention and novel treatment approaches.

Pharmacotherapy and Nutritional Supplements for Neovascular Eye Diseases

In this review, we aim to provide an overview of the recent findings about the treatment of neovascular retinal diseases. The use of conventional drugs and nutraceuticals endowed with antioxidant and anti-inflammatory properties that may support conventional therapies will be considered, with the final aim of achieving risk reduction (prevention) and outcome improvement (cooperation between treatments) of such sight-threatening proliferative retinopathies. For this purpose, we consider a medicinal product one that contains well-defined compound(s) with proven pharmacological and therapeutic effects, usually given for the treatment of full-blown diseases. Rarely are prescription drugs given for preventive purposes. A dietary supplement refers to a compound (often an extract or a mixture) used in the prevention or co-adjuvant treatment of a given pathology. However, it must be kept in mind that drug-supplement interactions may exist and might affect the efficacy of certain drug treatments. Moreover, the distinction between medicinal products and dietary supplements is not always straightforward. For instance, melatonin is formulated as a medicinal product for the treatment of sleep and behavioral problems; at low doses (usually below 1 mg), it is considered a nutraceutical, while at higher doses, it is sold as a psychotropic drug. Despite their lower status with respect to drugs, increasing evidence supports the notion of the beneficial effects of dietary supplements on proliferative retinopathies, a major cause of vision loss in the elderly. Therefore, we believe that, on a patient-by-patient basis, the administration of nutraceuticals, either alone or in association, could benefit many patients, delaying the progression of their disease and likely improving the efficacy of pharmaceutical drugs.

A Mediterranean Diet May Be Protective in the Development of Diabetic Retinopathy

The Mediterranean diet is recognized as one of the healthiest available dietary patterns. This perception results from its beneficial effects on the cardiovascular system and, also, on hypertension, diabetes, and cancer compared with other diets. Its impact on the course of diabetes is assessed in the available scientific literature; however, little information is available about its impact on diabetic retinopathy. The MD is characterized mainly by the consumption of fish, seafood, foods of plant origin, and fresh fruit and vegetables. It is also recommended to consume legumes, which are a source of folic acid, magnesium, iron, and dietary fiber. High consumption of nuts and unrefined grains is also recommended in the MD. Marine fish provide polyunsaturated acids from the omega-3 group. Olive oil plays a very important role, especially olive oil obtained from mechanical pressing. Additionally, olive oil contains vitamins E, K, and polyphenols. Polyphenols, which are present in a diverse range of vegetables, fruits, and seeds, have the ability to decrease oxidative stress, inflammation, and insulin resistance. Resveratrol is naturally found in grape skins and seeds, as well as in peanuts and berries, and is a constituent of red wine. Resveratrol can inhibit increased vascular leakage and loss of pericytes and regulate the level of VEGF protein in the retina, thus inhibiting the development of DR. Consumption of fruits, vegetables, fish, and olive oil may be correlated with a lower risk of diabetic retinopathy. This paper presents the definition of the Mediterranean diet and its influence on the course of diabetes and diabetic retinopathy.

New Insights on Dietary Polyphenols for the Management of Oxidative Stress and Neuroinflammation in Diabetic Retinopathy

Diabetic retinopathy (DR) is a neurodegenerative and vascular pathology that is considered one of the leading causes of blindness worldwide, resulting from complications of advanced diabetes mellitus (DM). Current therapies consist of protocols aiming to alleviate the existing clinical signs associated with microvascular alterations limited to the advanced disease stages. In response to the low resolution and limitations of the DR treatment, there is an urgent need to develop more effective alternative therapies to optimize glycemic, vascular, and neuronal parameters, including the reduction in the cellular damage promoted by inflammation and oxidative stress. Recent evidence has shown that dietary polyphenols reduce oxidative and inflammatory parameters of various diseases by modulating multiple cell signaling pathways and gene expression, contributing to the improvement of several chronic diseases, including metabolic and neurodegenerative diseases. However, despite the growing evidence for the bioactivities of phenolic compounds, there is still a lack of data, especially from human studies, on the therapeutic potential of these substances. This review aims to comprehensively describe and clarify the effects of dietary phenolic compounds on the pathophysiological mechanisms involved in DR, especially those of oxidative and inflammatory nature, through evidence from experimental studies. Finally, the review highlights the potential of dietary phenolic compounds as a prophylactic and therapeutic strategy and the need for further clinical studies approaching the efficacy of these substances in DR management.

Diet and ideal food pyramid to prevent or support the treatment of diabetic retinopathy, age-related macular degeneration, and cataracts

Many eye diseases, such as diabetic retinopathy (DR), age-related macular degeneration (AMD), and cataracts are preventable and treatable with lifestyle. The objective of this review is to assess the most recent research on the ideal dietary approach to prevent or support the treatment of DR, AMD, and cataracts, as well as to construct a food pyramid that makes it simple for people who are at risk of developing these pathologies to decide what to eat. The food pyramid presented here proposes what should be consumed every day: 3 portions of low glycemic index (GI) grains (for fiber and zinc content), 5 portions (each portion: ≥200 g/day) of fruits and vegetables (spinach, broccoli, zucchini cooked, green leafy vegetables, orange, kiwi, grapefruit for folic acid, vitamin C, and lutein/zeaxanthin content, at least ≥42 μg/day, are to be preferred), extra virgin olive (EVO) oil (almost 20 mg/day for vitamin E and polyphenols content), nuts or oil seeds (20-30 g/day, for zinc content, at least ≥15.8 mg/day); weekly: fish (4 portions, for omega-3 content and eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA) 0.35-1.4 g/day), white meat (3 portions for vitamin B12 content), legumes (2 portions for vegetal proteins), eggs (2 portions for lutein/zeaxanthin content), light cheeses (2 portions for vitamin B6 content), and almost 3-4 times/week microgreen and spices (saffron and curcumin). At the top of the pyramid, there are two pennants: one green, which indicates the need for personalized supplementation (if daily requirements cannot be met through diet, omega-3, and L-methylfolate supplementation), and one red, which indicates that certain foods are prohibited (salt and sugar). Finally, 3-4 times per week, 30-40 min of aerobic and resistance exercises are required.

Antioxidant Nutraceutical Strategies in the Prevention of Oxidative Stress Related Eye Diseases

This review aims to discuss the delicate balance between the physiological production of reactive oxygen species and the role of antioxidant nutraceutical molecules in managing radicals in the complex anatomical structure of the eye. Many molecules and enzymes with reducing and antioxidant potential are present in different parts of the eye. Some of these, such as glutathione, N-acetylcysteine, α-lipoic acid, coenzyme Q10, and enzymatic antioxidants, are endogenously produced by the body. Others, such as plant-derived polyphenols and carotenoids, vitamins B2, C, and E, zinc and selenium, and omega-3 polyunsaturated fatty acids, must be obtained through the diet and are considered essential nutrients. When the equilibrium between the production of reactive oxygen species and their scavenging is disrupted, radical generation overwhelms the endogenous antioxidant arsenal, leading to oxidative stress-related eye disorders and aging. Therefore, the roles of antioxidants contained in dietary supplements in preventing oxidative stress-based ocular dysfunctions are also discussed. However, the results of studies investigating the efficacy of antioxidant supplementation have been mixed or inconclusive, indicating a need for future research to highlight the potential of antioxidant molecules and to develop new preventive nutritional strategies.

Nutritional Factors: Benefits in Glaucoma and Ophthalmologic Pathologies

Glaucoma is a chronic optic neuropathy that can lead to irreversible functional and morphological damage if left untreated. The gold standard therapeutic approaches in managing patients with glaucoma and limiting progression include local drops, laser, and/or surgery, which are all geared at reducing intraocular pressure (IOP). Nutrients, antioxidants, vitamins, organic compounds, and micronutrients have been gaining increasing interest in the past decade as integrative IOP-independent strategies to delay or halt glaucomatous retinal ganglion cell degeneration. In our minireview, we examine the various nutrients and compounds proposed in the current literature for the management of ophthalmology diseases, especially for glaucoma. With respect to each substance considered, this minireview reports the molecular and biological characteristics, neuroprotective activities, antioxidant properties, beneficial mechanisms, and clinical studies published in the past decade in the field of general medicine. This study highlights the potential benefits of these substances in glaucoma and other ophthalmologic pathologies. Nutritional supplementation can thus be useful as integrative IOP-independent strategies in the management of glaucoma and in other ophthalmologic pathologies. Large multicenter clinical trials based on functional and morphologic data collected over long follow-up periods in patients with IOP-independent treatments can pave the way for alternative and/or coadjutant therapeutic options in the management of glaucoma and other ocular pathologies.

Diabetic retinopathy as the leading cause of blindness and early predictor of cascading complications-risks and mitigation

Proliferative diabetic retinopathy (PDR) the sequel of diabetic retinopathy (DR), a frequent complication of diabetes mellitus (DM), is the leading cause of blindness in the working-age population. The current screening process for the DR risk is not sufficiently effective such that often the disease is undetected until irreversible damage occurs. Diabetes-associated small vessel disease and neuroretinal changes create a vicious cycle resulting in the conversion of DR into PDR with characteristic ocular attributes including excessive mitochondrial and retinal cell damage, chronic inflammation, neovascularisation, and reduced visual field. PDR is considered an independent predictor of other severe diabetic complications such as ischemic stroke. A "domino effect" is highly characteristic for the cascading DM complications in which DR is an early indicator of impaired molecular and visual signaling. Mitochondrial health control is clinically relevant in DR management, and multi-omic tear fluid analysis can be instrumental for DR prognosis and PDR prediction. Altered metabolic pathways and bioenergetics, microvascular deficits and small vessel disease, chronic inflammation, and excessive tissue remodelling are in focus of this article as evidence-based targets for a predictive approach to develop diagnosis and treatment algorithms tailored to the individual for a cost-effective early prevention by implementing the paradigm shift from reactive medicine to predictive, preventive, and personalized medicine (PPPM) in primary and secondary DR care management.

Effects of Methylenetetrahydrofolate Reductase (MTHFR) Polymorphisms on Retinal Tissue Perfusion in Mild Diabetic Retinopathy Patients Receiving the Medical Food, Ocufolin®

Purpose

We evaluate the effects of methylenetetrahydrofolate reductase (MTHFR) polymorphisms on retinal tissue perfusion in patients with mild diabetic retinopathy (DR + PM) taking the medical food, Ocufolin^®, for 6 months.

Methods

Prospective, case-controlled study. Eight early diabetic retinopathy patients with common reduced function MTHFR polymorphisms (DR+PM) and 15 normal controls (NC) were recruited. MTHFR polymorphisms were subtyped as normal, C677T, or A1298C. Best corrected visual acuity (BCVA) was evaluated. Retinal blood flow velocity (BFV) was measured using Retinal Function Imager. Retinal tissue perfusion (RTP, blood flow rate per inner retinal volume) was calculated within a 2.5 mm diameter circle centered on the fovea. The medical food is intended to address ocular ischemia with high doses of vitamin B-complexes and antioxidants, including L-methylfolate, methylcobalamin, zinc, copper, lutein, vitamins C, D, E, and n-acetylcysteine. The subjects were provided with a medical food for a period of 6 months.

Results

BCVA and vascular indices of DR + PM patients at baseline were initially below those of NC and improved after medical food. Compared to baseline, DR + PM patients after the medical food had significantly improved BCVA during the follow-up period (P < 0.05). In comparison, overall RTP and arteriolar BFV were significantly increased at 6 months (P < 0.05). The changes varied with MTHFR subtypes. In patients with the C677T and the C677T/A1298C compound mutations, RTP was increased at 6 months as compared to that at baseline and 4 months (P < 0.05). In patients with only the A1298C mutation, all microcirculation metrics were increased from baseline at 4 and 6 months, but with less improvement at 6 months than at 4 months (P < 0.05).

Conclusion

Medical food was effective in improving both visual acuity and retinal tissue perfusion in DR + PM patients. The degree of improvement of retinal microcirculation varied among MTHFR subtypes.

DNA methylation in diabetic retinopathy: pathogenetic role and potential therapeutic targets

Background

Diabetic retinopathy (DR), a specific neuron-vascular complication of diabetes, is a major cause of vision loss among middle-aged people worldwide, and the number of DR patients will increase with the increasing incidence of diabetes. At present, it is limited in difficult detection in the early stages, limited treatment and unsatisfactory treatment effects in the advanced stages.

Main body

The pathogenesis of DR is complicated and involves epigenetic modifications, oxidative stress, inflammation and neovascularization. These factors influence each other and jointly promote the development of DR. DNA methylation is the most studied epigenetic modification, which has been a key role in the regulation of gene expression and the occurrence and development of DR. Thus, this review investigates the relationship between DNA methylation and other complex pathological processes in the development of DR. From the perspective of DNA methylation, this review provides basic insights into potential biomarkers for diagnosis, preventable risk factors, and novel targets for treatment.

Conclusion

DNA methylation plays an indispensable role in DR and may serve as a prospective biomarker of this blinding disease in its relatively early stages. In combination with inhibitors of DNA methyltransferases can be a potential approach to delay or even prevent patients from getting advanced stages of DR.

Research Progress on Mitochondrial Dysfunction in Diabetic Retinopathy

Diabetic Retinopathy (DR) is one of the most important microvascular complications of diabetes mellitus, which can lead to blindness in severe cases. Mitochondria are energy-producing organelles in eukaryotic cells, which participate in metabolism and signal transduction, and regulate cell growth, differentiation, aging, and death. Metabolic changes of retinal cells and epigenetic changes of mitochondria-related genes under high glucose can lead to mitochondrial dysfunction and induce mitochondrial pathway apoptosis. In addition, mitophagy and mitochondrial dynamics also change adaptively. These mechanisms may be related to the occurrence and progression of DR, and also provide valuable clues for the prevention and treatment of DR. This article reviews the mechanism of DR induced by mitochondrial dysfunction, and the prospects for related treatment.

Do Nutrients and Nutraceuticals Play a Role in Diabetic Retinopathy? A Systematic Review

Diabetic retinopathy (DR) is a multifactorial neuro-microvascular disease, whose prevalence ranges from 25% to 60% of subjects affected by diabetes mellitus, representing the main cause of legal blindness in adults of industrialized countries. The treatment of advanced stage of DR is based on invasive and expensive therapies, while few strategies are available for the early stage or prevention. The mechanisms underlying DR involve a complex interplay between the detrimental effects of hyperglycemia, dyslipidemia, hypoxia, and oxidative stress, providing several pathways potentially targeted by nutrients and nutraceuticals. In this study, we conducted a systematic review of observational and interventional studies, evaluating the effect of nutrients and/or nutraceuticals on the risk of DR and their potential use for the treatment of patients with DR. The analysis of the 41 included studies (27 observational and 14 interventional studies) suggests a promising preventive role of some nutrients, in particular for vitamins B (i.e., B1 and B12), D, and E. However, further investigations are necessary to clarify the potential clinical application of nutraceuticals in the prevention and treatment of DR.

Vitamin E and Non-Communicable Diseases: A Review

Vitamin E, a nutrient found in several foods, comprises eight lipophilic vitamers, the α-, β-, γ- and δ-tocopherols and the α-, β-, γ- and δ-tocotrienols. This vitamin is capable of exerting antioxidant and anti-inflammatory activities, and acting as immunomodulators. Despite these well-known biological activities, the findings regarding the ability of vitamin E and its serum metabolites to prevent and/or control chronic disease are often conflicting and inconsistent. In this review, we have described the metabolism of vitamin E and its interaction with the gut microbiota, considering that these factors may be partially responsible for the divergent results obtained. In addition, we focused on the correlations between vitamin E serum levels, dietary intake and/or supplementation, and the main non-communicable diseases, including diabetes mellitus, asthma, cardiovascular diseases, and the four most common cancers (breast cancer, lung cancer, colorectal cancer, and prostate cancer) with the intention of providing an overview of its health effects in the non-communicable-diseases prevention.

Reactive Oxygen Species Scavenging Nanomedicine for the Treatment of Ischemic Heart Disease

Ischemic heart disease (IHD) is the leading cause of disability and mortality worldwide. Reactive oxygen species (ROS) have been shown to play key roles in the progression of diabetes, hypertension, and hypercholesterolemia, which are independent risk factors that lead to atherosclerosis and the development of IHD. Engineered biomaterial-based nanomedicines are under extensive investigation and exploration, serving as smart and multifunctional nanocarriers for synergistic therapeutic effect. Capitalizing on cell/molecule-targeting drug delivery, nanomedicines present enhanced specificity and safety with favorable pharmacokinetics and pharmacodynamics. Herein, the roles of ROS in both IHD and its risk factors are discussed, highlighting cardiovascular medications that have antioxidant properties, and summarizing the advantages, properties, and recent achievements of nanomedicines that have ROS scavenging capacity for the treatment of diabetes, hypertension, hypercholesterolemia, atherosclerosis, ischemia/reperfusion, and myocardial infarction. Finally, the current challenges of nanomedicines for ROS-scavenging treatment of IHD and possible future directions are discussed from a clinical perspective.

Metagenomic shotgun sequencing and metabolomic profiling identify specific human gut microbiota associated with diabetic retinopathy in patients with type 2 diabetes

Background

Diabetic retinopathy (DR) is a common microvascular complication of diabetes mellitus (DM) and is one of the leading causes of blindness among DM patients. However, the molecular mechanism involving DR remains unclear.

Methods

A case–control study with age-, sex-, and duration-matched diabetic patients and controls was conducted, which included 15 type 2 DM (T2DM) patients with DR and 15 T2DM patients without DR. Shotgun sequencing and non-targeted metabolomic profiling analyses of fecal samples were performed, and comprehensive bioinformatics analyses were conducted.

Results

Using metagenomic analyses, we identified 293,460 unique genes in the non-DR group, while that in the DR group was 283,235, and the number of overlapping genes was 1,237,914. Regarding phylum levels, Actinobacteria decreased but Bacteroidetes increased in the DR group when compared with those in the control group. Regarding genus levels, Bifidobacterium and Lactobacillus decreased. Cellular processes, environmental information processes, and metabolism-related pathways were found at higher levels in the gut microbiome of DR patients. Using metabolomic analyses, we found 116 differentially expressed metabolites with a positive ion model and 168 differentially expressed metabolites with a negative ion model between the two groups. Kyoto Encyclopedia of Genes and Genomes annotation revealed six pathways with different levels between DR and diabetic controls, namely, cellular processes, environmental information processing, genetic information processing, human diseases, organismal systems and metabolism. Moreover, lysine biosynthesis and lysine degradation were enriched using a positive model, but histidine metabolism and β-alanine metabolism were enriched using a negative model.

Conclusions

Together, the metagenomic profiles of DR patients indicated different gut microbiota compositions and characteristic fecal metabolic phenotypes in DR patients. Our findings of microbial pathways therefore provided potential etiological and therapeutic targets for DR patients.

Arterial Hypertension and the Hidden Disease of the Eye: Diagnostic Tools and Therapeutic Strategies

Hypertension is a major cardiovascular risk factor that is responsible for a heavy burden of morbidity and mortality worldwide. A critical aspect of cardiovascular risk estimation in hypertensive patients depends on the assessment of hypertension-mediated organ damage (HMOD), namely the generalized structural and functional changes in major organs induced by persistently elevated blood pressure values. The vasculature of the eye shares several common structural, functional, and embryological features with that of the heart, brain, and kidney. Since retinal microcirculation offers the unique advantage of being directly accessible to non-invasive and relatively simple investigation tools, there has been considerable interest in the development and modernization of techniques that allow the assessment of the retinal vessels’ structural and functional features in health and disease. With the advent of artificial intelligence and the application of sophisticated physics technologies to human sciences, consistent steps forward have been made in the study of the ocular fundus as a privileged site for diagnostic and prognostic assessment of diverse disease conditions. In this narrative review, we will recapitulate the main ocular imaging techniques that are currently relevant from a clinical and/or research standpoint, with reference to their pathophysiological basis and their possible diagnostic and prognostic relevance. A possible non pharmacological approach to prevent the onset and progression of retinopathy in the presence of hypertension and related cardiovascular risk factors and diseases will also be discussed.

Effect of a Fixed Combination of Curcumin, Artemisia, Bromelain, and Black Pepper Oral Administration on Optical Coherence Tomography Angiography Indices in Patients with Diabetic Macular Edema

Background: To investigate the effects of a fixed combination of Curcumin (200 mg), Artemisia (80 mg), Bromelain (80 mg), and Black pepper (2 mg) on vascular parameters in mild to moderate diabetic macular edema (DME). Design: Prospective, case-control study. Methods: Fifty-six patients affected by diabetes mellitus type II were enrolled in the study. Twenty-eight patients with DME received 2 tablets/day, before meals of a dietary complementary supplement containing in fixed combination Curcumin (200 mg), Artemisia (80 mg), Bromelain (80 mg), and Black pepper (2 mg) (Intravit®, OFFHEALTH Spa, Firenze, Italy) for 6 months. Twenty-eight age-matched subjects affected by diabetes mellitus type II were given placebo and served as control group. Patients underwent best correct visual acuity (BCVA), swept optical coherence tomography (OCT), and OCT-Angiography (OCTA). OCTA images of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) were obtained for each eye. By the end of the follow-up patients were defined responder to the therapy when a decrease of more than 30 μm was registered in central retinal thickness (CRT) measurement, while a poor responder was determined by the absence of reduction or an increase in central retinal thickness at 6 months. We assessed the foveal avascular zone (FAZ) area, vessel density and quantified the number of microaneurysms in each layer. Results: A significant improvement of BCVA and CRT reduction was recorded at 6 months follow-up in the dietary complementary supplementation group compared to control (respectively p = 0.028 and p = 0.0003). VD of the total capillary plexus, microaneurysms count, glycaemia and HbA1c did not vary over the follow-up period between groups. Within the Intravit® group, poor responders tended to show a larger FAZ area, more microaneurysms, and a lower VD in the DCP compared to the good responders group (p < 0.0001). Conclusions: A fixed combination of Curcumin, Artemisia, Bromelain, and Black pepper oral administration may have a positive impact on central retinal thickness, visual acuity, and VD of the DCP in compensated type 2 diabetic patients with mild DME.

The Effect of Diet and Lifestyle on the Course of Diabetic Retinopathy-A Review of the Literature

Diabetes is a major social problem. As shown by epidemiological studies, the world incidence of diabetes is increasing and so is the number of people suffering from its complications. Therefore, it is important to determine possible preventive tools. In the prevention of diabetic retinopathy, it is essential to control glycemia, lipid profile and blood pressure. This can be done not only by pharmacological treatment, but first of all by promoting a healthy lifestyle, changing dietary habits and increasing physical activity. In our work, we present a review of the literature to show that physical exercise and an adequate diet can significantly reduce the risk of diabetes and diabetic retinopathy.

Preventive Efficacy of an Antioxidant Compound on Blood Retinal Barrier Breakdown and Visual Dysfunction in Streptozotocin-Induced Diabetic Rats

In diabetic retinopathy (DR), high blood glucose drives chronic oxidative stress and inflammation that trigger alterations of the neurovascular balance finally resulting in vascular abnormalities and retinal cell death, which converge towards altered electroretinogram (ERG). In the last years, a growing body of preclinical evidence has suggested that nutrients with anti-inflammatory/antioxidant properties can be able to hamper DR progression since its very early stages. In the present study, we used a streptozotocin-induced rat model of DR, which mimics most aspects of the early stages of human DR, to test the preventive efficacy of a novel compound containing cyanidin-3-glucoside (C3G), verbascoside and zinc as nutrients with antioxidant and anti-inflammatory properties. Western blot, immunofluorescence and electroretinographic analyses demonstrated a dose-dependent inhibition of oxidative stress- and inflammation-related mechanisms, with a significant counterpart in preventing molecular mechanisms leading to DR-associated vasculopathy and its related retinal damage. Preventive efficacy of the compound on dysfunctional a- and b-waves was also demonstrated by electroretinography. The present demonstration that natural compounds, possibly as a consequence of vascular rescue following ameliorated oxidative stress and inflammation, may prevent the apoptotic cascade leading to ERG dysfunction, adds further relevance to the potential application of antioxidants as a preventive therapy to counteract DR progression.

Methylenetetrahydrofolate (MTHFR), the One-Carbon Cycle, and Cardiovascular Risks

The 5-10-methylenetetrahydrofolate reductase (MTHFR) enzyme is vital for cellular homeostasis due to its key functions in the one-carbon cycle, which include methionine and folate metabolism and protein, DNA, and RNA synthesis. The enzyme is responsible for maintaining methionine and homocysteine (Hcy) balance to prevent cellular dysfunction. Polymorphisms in the MTHFR gene, especially C677T, have been associated with various diseases, including cardiovascular diseases (CVDs), cancer, inflammatory conditions, diabetes, and vascular disorders. The C677T MTHFR polymorphism is thought to be the most common cause of elevated Hcy levels, which is considered an independent risk factor for CVD. This polymorphism results in an amino acid change from alanine to valine, which prevents optimal functioning of the enzyme at temperatures above 37 °C. Many studies have been conducted to determine whether there is an association between the C677T polymorphism and increased risk for CVD. There is much evidence in favour of this association, while several studies have concluded that the polymorphism cannot be used to predict CVD development or progression. This review discusses current research regarding the C677T polymorphism and its relationship with CVD, inflammation, diabetes, and epigenetic regulation and compares the evidence provided for and against the association with CVD.

Effects of Ocufolin on retinal microvasculature in patients with mild non-proliferative diabetic retinopathy carrying polymorphisms of the MTHFR gene

INTRODUCTION

To evaluate effects of Ocufolin on retinal microvasculature in mild non-proliferative diabetic retinopathy patients who carried methylenetetrahydrofolate reductase (MTHFR) polymorphisms (DR+MTHFRP).

RESEARCH DESIGN AND METHODS

This is a prospective cohort study. Eight DR+MTHFRP (administrated Ocufolin for 6 months) and 15 normal controls (NCs) were recruited. MTHFR polymorphisms were subtyped as normal, C677T, or A1298C. Best-corrected visual acuity (BCVA) was evaluated. Retinal vessel density (VD) and microstructure were evaluated by optical coherence tomography angiography.

RESULTS

BCVA and vascular indices of DR+MTHFRP at baseline were worse than those of NC and improved. Compared with baseline, DR+MTHFRP had significantly improved BCVA during follow-up period (p<0.05). VD of superficial vascular plexus was increased at 4 months (p=0.012), while VD of retinal vascular network did not change (p>0.05). Carriers of A1298C and C677T showed statistically significant increase in VD at all layers by 6 months, while carriers of C677T alone showed no significant change and carriers of A1298C alone showed decreased density from 4 months to 6 months. Microstructure did not change during the follow-up period.

CONCLUSION

A 6-month intake of Ocufolin is capable of reversing structural changes of microangiopathy in mild non-proliferative DR+MTHFRP. This suggests a novel way to address these impairments prior to catastrophic vision loss.

Nutraceutical Strategy to Counteract Eye Neurodegeneration and Oxidative Stress in Drosophila melanogaster Fed with High-Sugar Diet

Aberrant production of reactive oxygen species (ROS) is a common feature of damaged retinal neurons in diabetic retinopathy, and antioxidants may exert both preventive and therapeutic action. To evaluate the beneficial and antioxidant properties of food supplementation with Lisosan G, a powder of bran and germ of grain (Triticum aestivum) obtained by fermentation with selected lactobacillus and natural yeast strains, we used an in vivo model of hyperglycemia-induced retinal damage, the fruit fly Drosophila melanogaster fed with high-sucrose diet. Lisosan G positively affected the visual system of hyperglycemic flies at structural/functional level, decreased apoptosis, and reactivated protective autophagy at the retina internal network. Also, in high sucrose-fed Drosophila, Lisosan G reduced the levels of brain ROS and retina peroxynitrite. The analysis of oxidative stress-related metabolites suggested 7,8-dihydrofolate, uric acid, dihydroorotate, γ-L-glutamyl-L-cysteine, allantoin, cysteinyl-glycine, and quinolate as key mediators of Lisosan G-induced inhibition of neuronal ROS, along with the upregulation of glutathione system. Of note, Lisosan G may impact oxidative stress and the ensuing retinal cell death, also independently from autophagy, although the autophagy-ROS cross-talk is critical. This study demonstrated that the continuous supplementation with the alimentary integrator Lisosan G exerts a robust and multifaceted antioxidant effect on retinal neurons, thus providing efficacious neuroprotection of hyperglycemic eye.

Citicoline and Vitamin B12 Eye Drops in Type 1 Diabetes: Results of a 36-Month Pilot Study Evaluating Macular Electrophysiological Changes

Introduction

Our aim was to evaluate the effects of 36 months of treatment with citicoline and vitamin B₁₂ eye drops on macular function in patients with type 1 diabetes (DM1) with mild signs of non-proliferative diabetic retinopathy (NPDR).

Methods

A prospective, randomized, interventional, monocentric, double-masked study was conducted. Twenty patients with DM1 were enrolled and randomly divided into two groups: the DC group (10 patients; mean age ± standard deviation 46.86 ± 8.78 years) in which one eye of each patient was treated with citicoline and vitamin B₁₂ eye drops (OMK2^®, Omikron Italia srl, Italy, one drop thrice daily) for a period of 36 months; the DP group (10 patients; mean age ± standard deviation 47.89 ± 7.74 years) in which one eye of each patient was treated with placebo (eye drops containing hypromellose 0.3%, one drop thrice daily) for a period of 36 months. A total of 18 eyes (10 from the DP and 8 from the DC group, respectively) completed the study. In both groups, multifocal electroretinogram (mfERG) recordings were assessed at baseline and after 36 months. In mfERG analysis, the N1–P1 response amplitude density (RAD) evaluated in the 0–2.5° (ring 1), in the 2.5–5° (ring 2), in the 5–10° (ring 3), and in the 0–10° (ring 1 + ring 2 + ring 3) were considered.

Results

With respect to baseline, after 36 months of follow-up, the mfERG RADs recorded in R1, R2, R3, and R1 + R2 + R3 were significantly increased (i.e., R1 + R2 + R3 RAD from 21.552 ± 2.522 nV/degree² at baseline to 26.912 ± 2.850 nV/degree² at 36 months) in DC eyes, whereas in DP eyes they were significantly reduced (i.e., R1 + R2 + R3 RAD from 21.033 ± 3.574 nV/degree² at baseline to 16.151 ± 3.571 nV/degree² at 36 months).

Conclusions

This study indicates that patients with NPDR treated with citicoline and vitamin B₁₂ eye drops for a 36-month period achieved an improvement of the macular bioelectrical responses detectable by mfERG recordings. By contrast, during the same period of follow-up, patients with NPDR treated with placebo showed a worsening of the macular function.

Nutraceutical Supplementation Ameliorates Visual Function, Retinal Degeneration, and Redox Status in rd10 Mice

Retinitis pigmentosa (RP) is a group of inherited retinal dystrophies characterized by progressive degeneration of photoreceptor cells. Ocular redox status is altered in RP suggesting oxidative stress could contribute to their progression. In this study, we investigated the effect of a mixture of nutraceuticals with antioxidant properties (NUT) on retinal degeneration in rd10 mice, a model of RP. NUT was orally administered to rd10 mice from postnatal day (PD) 9 to PD18. At PD18 retinal function and morphology were examined by electroretinography (ERG) and histology including TUNEL assay, immunolabeling of microglia, Müller cells, and poly ADP ribose polymers. Retinal redox status was determined by measuring the activity of antioxidant enzymes and some oxidative stress markers. Gene expression of the cytokines IL-6, TNFα, and IL-1β was assessed by real-time PCR. NUT treatment delayed the loss of photoreceptors in rd10 mice partially preserving their electrical responses to light stimuli. Moreover, it ameliorated redox status and reduced inflammation including microglia activation, upregulation of cytokines, reactive gliosis, and PARP overactivation. NUT ameliorated retinal functionality and morphology at early stages of RP in rd10 mice. This formulation could be useful as a neuroprotective approach for patients with RP in the future.

Effect of A Multinutrient Complex on Retinal Microcirculation in Diabetic Patients Investigated Using an Adaptive Optics Retinal Camera

CONTEXT

Alimentary supplements may have beneficial effects on retinal microvasculature in diabetic patients.

OBJECTIVE AND DESIGN

State-of-the-art imaging techniques were used to assess retinal microcirculation in diabetic patients in an observational study before and after 3 months treatment with a multinutrient complex including resveratrol, vitamins D3, C, E, essential fatty acids, trace elements (zinc and copper) and macular pigments (lutein and zeaxanthin)-Resvega.

SUBJECTS AND METHODS

Fifteen subjects were included in this study. Adaptive optics ophthalmoscopy was used to measure the parameters of temporal retinal arterioles. Optical coherence tomography angiography was employed to assess foveal avascular zone and vessel densities of the superficial capillary plexus, deep capillary plexus and choricapillary plexus.

RESULTS

After 3 months of treatment, there was a statistically significant median decrease in wall-to-lumen ratio (p=0.0001). The same tendencies were noticed for wall thickness values (p=0.008) and wall cross sectional area values (p=0.001). On the other side, no significant changes were noticed concerning the OCTA parameters.

CONCLUSIONS

Resvega seems to have a beneficial effect on the retinal arterioles in diabetic patients.