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.

White tea modulates antioxidant defense of endurance-trained rats.

The interest in nutritional strategies that may counteract the deleterious oxidative effects induced by strenuous exercises is remarkable. Herein, the impact of white tea (Camellia sinensis) (WT), a polyphenol-rich beverage, on antioxidant status in endurance-trained rats after one session of exhaustive exercise were evaluated. Male Wistar rats were divided into groups, which received: control groups - water, and testing groups - WT1 (0.25%; w/v) or WT2 (0.5%; w/v). Drinks were consumed, ad libitum, for 5 or 10 weeks, concomitantly with the running training. Exhaustive running tests were applied before and after the experimental periods. WT intake increased the serum antioxidant capacity of rats in a dose-dependent manner (P < 0.001), which was unaccompanied by the activity of endogenous antioxidant enzymes SOD, GPx, and GR, and GSH content. Inflammatory markers in serum [IL-1ß (P = 0.004) and IL-6 (P = 0.001)] could be downregulated by tea intake. In liver tissue, lower levels of lipid oxidation (P < 0.05) and improved antioxidant defenses (SOD, GPx, GR, and GSH, P < 0.05) were related to the consumption of WT in both doses, supporting protective effects in this responsible metabolic organ. In conclusion, long-term consumption of WT could be a promising adjuvant to exercise-stress management, emphasizing its ability to regulate antioxidant responses and prevent oxidative tissue damage.

Gut microbiota: A potential therapeutic target for management of diabetic retinopathy?

Diabetic Retinopathy (DR) is one of the main complications of Diabetes Mellitus (DM), drastically impacting individuals of working age over the years, being one of the main causes of blindness in the world. The existing therapies for its treatment consist of measures that aim only to alleviate the existing clinical signs, associated with the microvasculature. These treatments are limited only to the advanced stages and not to the preclinical ones. In response to a treatment with little resolution and limited for many patients with DM, investigations of alternative therapies that make possible the improvement of the glycemic parameters and the quality of life of subjects with DR, become extremely necessary. Recent evidence has shown that deregulation of the microbiota (dysbiosis) can lead to low-grade, local and systemic inflammation, directly impacting the development of DM and its microvascular complications, including DR, in an axis called the intestine-retina. In this regard, the present review seeks to comprehensively describe the biochemical pathways involved in DR as well as the association of the modulation of these mechanisms by the intestinal microbiota, since direct changes in the microbiota can have a drastic impact on various physiological processes. Finally, emphasize the strong potential for modulation of the gut-retina axis, as therapeutic and prophylactic target for the treatment of DR.

Collagen supplementation as a complementary therapy for the prevention and treatment of osteoporosis and osteoarthritis: a systematic review / Suplementação com colágeno como terapia complementar na prevenção e tratamento de osteoporose e osteoartrite: uma revisão sistemática

Introduction Collagen hydrolysate is recognized as a safe nutraceutical, whose combination of amino acids stimulates the synthesis of collagen in the extracellular matrix of cartilage and other tissues. Objective to conduct a systematic review of literature on the action of collagen hydrolysate in bone and cartilaginous tissue and its therapeutic use against osteoporosis and osteoarthritis. Method a study of the PubMed, MEDLINE, LILACS, and SciELO databases was performed. Articles published in English and Portuguese in the period of 1994 to 2014 were considered. Results: the sample comprised nine experimental articles with in vivo (animals and humans) andin vitro (human cells) models, which found that the use of different doses of collagen hydrolysate were associated with the maintenance of bone composition and strength, and the proliferation and cell growth of cartilage. Conclusion hydrolyzed collagen has a positive therapeutic effect on osteoporosis and osteoarthritis with a potential increase in bone mineral density, a protective effect on articular cartilage, and especially in the symptomatic relief of pain.

Introdução O colágeno hidrolisado é reconhecido como um nutracêutico seguro, cuja combinação de aminoácidos estimula a síntese de colágeno nas cartilagens e na matriz extracelular de outros tecidos. Objetivo Realizar uma revisão sistemática da literatura sobre a ação do colágeno hidrolisado no tecido ósseo e cartilaginoso e suas finalidades terapêuticas na osteoporose e osteoartrite. Método A pesquisa foi realizada nas bases de dados Pubmed; MEDLINE; LILACS; SciELO. Foram considerados artigos publicados no período de 1994 a 2014, nos idiomas inglês e português. Resultados A amostra final foi composta por nove artigos experimentais com modelosin vivo (animais e humanos) e in vitro(células humanas), que descrevem a utilização de diferentes doses de colágeno hidrolisado associadas à manutenção da composição e resistência óssea e proliferação e crescimento celular da cartilagem. Conclusão O colágeno hidrolisado tem função terapêutica positiva na osteoporose e osteoartrite com potencial aumento da densidade mineral óssea, efeito protetor da cartilagem articular e principalmente no alívio sintomático em quadros de dor.