Search results for "Retina"

Incorporation of lutein and docosahexaenoic acid from dietary microalgae into the retina in quail

2015

Abstract Lutein and docosahexaenoic acid (DHA) are associated with the prevention of age-related macular degeneration (AMD). Since microalgae are potent natural sources of these nutrients, their nutritional value should be evaluated based on the bioavailability of lutein and DHA for the retina via the plasmatic compartment. In this study, quail were fed for 5 months either with a diet supplemented or deprived with microalgae rich in lutein and DHA. In the microalgae-fed group, the retinal concentrations of lutein and zeaxanthin gradually increased whereas in plasma, these compounds started to increase from the first month of supplementation. We also observed a significant increase in retina…

Xanthophylls: from blood to retina

2010

Xanthophylls are dietary lipophilic compounds. Among them, lutein and zeaxanthin are the major carotenoids found in the human lens and retina, and referred as macular pigment within the retina. Lutein and zeaxanthin cannot be synthesized endogenously. They may therefore be considered as essential and must be provided by adequate dietary intakes. Lutein and zeaxanthin are present in various food items, mainly in plants and fruits such as green vegetables or yellow-orange fruits, as well as in a few animal sources, such as egg yolk. Epidemiological studies consistently suggest that dietary lutein and zeaxanthin are protective factors against the development of Age-Related Maculopathies and Ag…

Protective role of xanthophylls

2010

Xanthophylls, also known as carotenoids are a group of natural fat-soluble pigments that are especially abundant in green and yellow-orange fruits and vegetables. Based on epidemiologic data, it is now evident that carotenoids provide health benefits and particularly in eye diseases. Molecular characterization of retinal carotenoids has shown that there were actually two xanthophylls that are concentrated in macular region, namely lutein and zeaxanthin. Thanks to a strategic position within inner retinal layers, lutein and zeaxanthin are suspected to act as antioxidants in the retina in order to limit oxidative stress that results from metabolism of light. In addition, they are also suppose…

Amino acid transport in the retina.

1978

The uptake, exit, homoexchange, inhibitory pattern, and kinetic analysis of transport of three amino acids were studied in the isolated retina of adult rat under different metabolic conditions. Only in the case of glycine, uptake and exit were shown to duplicate the processes observed in brain slices. In the case of lysine, glucose and oxygen showed an inhibitory effect, but with glutamate spontaneous exit could not be measured. It was also found that the rate of homoexchange for glycine and glutamate, but not for lysine, increases in the presence of oxygen and glucose.

Reliability and Intersession Agreement of Microperimetric and Fixation Measurements Obtained with a New Microperimeter in Normal Eyes.

2015

Purpose: To evaluate the reliability and intersession agreement of measurements of retinal sensitivity as well as of the fixation pattern obtained in healthy eyes with a microperimeter integrating the mechanism of the scanning laser ophthalmoscope (SLO) with the static perimetry. Methods: This study included a sample of 44 healthy eyes of 44 subjects of a mean age of 27.0 ± 8.5 years. In all cases, microperimetric exams with the MAIA system (Centervue, Padova, Italy) were performed in three different sessions to evaluate the intersession repeatability. The consistency of measurements was analyzed by using the Friedman test and by analyzing the correlation between consecutive measurements. A…

Normal Values for Microperimetry with the MAIA Microperimeter: Sensitivity and Fixation Analysis in Healthy Adults and Children

2017

Purpose To establish normative values of retinal sensitivity and parameters describing the fixation pattern using macular analyzer integrity assessment (MAIA) microperimetry (Centervue, Padova, Italy) in adults and children. Methods A sample of 237 eyes of 237 healthy subjects aged between 10 and 70 years (mean age 30.63 ± 16.23 years) was evaluated using the MAIA microperimeter. The following parameters provided by the MAIA device were evaluated: average threshold (AT), macular integrity, fixation indexes (P1% and P2%), bivariate contour ellipse area (BCEA) for 95% and 63% of points, and horizontal (H) and vertical (V) axes of the ellipse of fixation. Differences between different age-rela…

2020

Age-related macular degeneration (AMD) is a degenerative disease of the retina where the molecular mechanism involves the production of vascular endothelial growth factor (VEGF), a factor of poor prognosis of the progression of the disease. Previous studies have shown that resveratrol, a polyphenol of grapevines, can prevent VEGF secretion induced by stress from retinal cells. Considering the fundamental role played by VEGF in development and progression of AMD, we investigate the potential effect of red wine extract (RWE) on VEGF secretion and its signaling pathway in human retinal cells ARPE-19. To examine the effect of RWE in ARPE-19, a quantitative and qualitative analysis of the RWE wa…

Dual disruption of aldehyde dehydrogenases 1 and 3 promotes functional changes in the glutathione redox system and enhances chemosensitivity in nonsm…

2020

AbstractAldehyde dehydrogenases (ALDHs) are multifunctional enzymes that oxidize diverse endogenous and exogenous aldehydes. We conducted a meta-analysis based on The Cancer Genome Atlas and Gene Expression Omnibus data and detected genetic alterations in ALDH1A1, ALDH1A3, or ALDH3A1, 86% of which were gene amplification or mRNA upregulation, in 31% of nonsmall cell lung cancers (NSCLCs). The expression of these isoenzymes impacted chemoresistance and shortened survival times in patients. We hypothesized that these enzymes provide an oxidative advantage for the persistence of NSCLC. To test this hypothesis, we used genetic and pharmacological approaches with DIMATE, an irreversible inhibito…

Melanocortin receptor agonists MCR1-5protect photoreceptors from high-glucose damage and restore antioxidant enzymes in primary retinal cell culture

2016

Retinal photoreceptors are particularly vulnerable to local high-glucose concentrations. Oxidative stress is a risk factor for diabetic retinopathy development. Melanocortin receptors represent a family of G-protein-coupled receptors classified in five subtypes and are expressed in retina. Our previous data indicate that subtypes 1 and 5 receptor agonists exert a protective role on experimental diabetic retinopathy. This study focuses on their role in primary retinal cell cultures in high-glucose concentrations. After eye enucleation from wild-type male C57BL/6 mice, retinal cells were isolated, plated in high-glucose concentration and treated with melanocortin receptors 1 and 5 agonists an…

Retinal arteriole reactivity in mice lacking the endothelial nitric oxide synthase (eNOS) gene

2018

Dysfunctional vascular endothelial nitric oxide synthase (eNOS) has been proposed to play a main pathophysiological role in various ocular diseases. The aim of the present study was to test the hypothesis that the chronic lack of eNOS impairs endothelium-dependent vasodilation in retinal arterioles. The relevance of eNOS for mediating vascular responses was studied in retinal vascular preparations from eNOS-deficient mice (eNOS-/-) and wild-type controls in vitro. Changes in luminal diameter in response to vasoactive agents were measured by videomicroscopy. The thromboxane mimetic, U46619, induced similar concentration-dependent constriction of retinal arterioles in eNOS-/- and wild-type mi…