Search results for "dégénérescence"
showing 10 items of 17 documents
Oxidation-Induced Increase In Photoreactivity of Bovine Retinal Lipid Extract
2017
Open access original paper Source : 10th EPR Workshop on Applications of EPR in Biology and Medicine, 2016 in Krakow, POLAND.; International audience; The mammalian retina contains a high level of polyunsaturated fatty acids, including docosahexaenoic acid (22:6) (DHA), which are highly susceptible to oxidation. It has been shown that one of the products of DHA oxidation-carboxyethylpyrrole (CEP), generated in situ, causes modifications of retinal proteins and induces inflammation response in the outer retina. These contributing factors may play a role in the development of age-related macular degeneration (AMD). It is also possible that some of the lipid oxidation products are photoreactiv…
Problématiques de la nutrition en ophtalmologie – application à la dégénérescence maculaire liée à l’âge
2014
Nutrition in ophthalmology – clinical application to age-related macular degeneration «Let food be your medicine.» This contribution from Hippocrates is still timely addressed, especially in the field of ophthalmology. Observational epidemiology reports close associations between food habits and the risk or prevention of several ocular pathologies such as cataract or Age-related Macular Degeneration (AMD). Anti-oxidant vitamins, minerals and lipids are the nutrients that have been the most widely studied. Interventional epidemiology and experimental works partially corroborated these findings. Unexpectedly, the benefit of long chain omega 3 polyunsaturated fatty acids in the prevention of l…
Preparation and characterization of extracts argania spinosa and argan oil and evaluation of their neuroprotective effects in vivo and in vitro
2016
من بين الزيوت الطبيعية أثار زيت أركان الكثير من الاهتمام. فقد استخدم زيت الأركان في الطب التقليدي، من قبل نساء البربرللعناية بالجسم و الشعر، و لمنع بعض الأمراض القلب و الأوعية الدموية . يتميز زيت الأركان بوظائفه التي تخص خفض الكوليسترول، مكافحة داء السكري ومكافحة التكاثر في خطوط الخلايا السرطانية البشرية للبروستات. يعتبر زيت اركان غنيا بالأحماض الدهنية غير المشبعة، البوليفينول، التوكوفيرول و الستيرول .هذه المواد تجعله مادة مضادة للأكسدة.يتركز دور مضادات الأكسدة الغذائية في وظيفة الجهاز العصبي وبعض الأمراض المرتبطة بالعمر على فيتامين E الذي يعتبر المكون الرئيسي لزيت أركان . الهدف من هذا العمل هو أولا دراسة كيميائية لنبتة اركان وتقييم القوة المضادة للأكسدة لمقتطفات هذه النبتة مع توصيف شامل لت…
Involvement of Kv3.1 potassium chanels in 7-ketocholesterol, 24S-hydroxycholesterol and C24 : 0-induced lipotoxicity on 158N and BV-2 cells : relatio…
2017
Potassium (K+) is involved in the regulation of cellular excitability, cell cycle regulation, cell viability, neuroprotection and maintenance of microglial and oligodendrocytic functions. Potassium dysfunction, described in several neurodegenerative diseases such as Alzheimer's Disease (AD), multiple sclerosis (MS), Parkinson's disease and Huntington's disease, may be a potential therapeutic target. The underlying toxic mechanisms of these neurodegenerative pathologies involve oxysterols, which are oxidized cholesterol derivatives, and fatty acids including those associated with peroxisomal metabolism. 7-ketocholesterol (7KC), 24S-hydroxycholesterol (24S-OHC) and tetracosanoic acid (C24:0),…
Inflammatory cytokines decrease viability and alter ganglioside profile in retinal pigment epithelium cells
2013
Purpose Early stages of Age related Macular Degeneration (AMD) are characterized by dysfunction and degeneration of the retinal pigment epithelium (RPE) cells, which participate in the death of the overlying photoreceptors ultimately leading to loss of vision. Gangliosides (GG) make a wide and heterogeneous family of sialic-acid-containing glycosphingolipids, composed of a sugar chain branched on a ceramide. They are major components of cellular membranes, particularly abundant in the brain and nervous tissue, including retina. While their developmental and neuroprotective actions have been demonstrated, their precise role in retina’s function and its pathologies is still poorly understood.…
L'identité de Fay en théorie des systèmes intégrables
2011
Fay's identity on Riemann surfaces is a powerful tool in the context of algebro-geometric solutions to integrable equations. This relation generalizes a well-known identity for the cross-ratio function in the complex plane. It allows to establish relations between theta functions and their derivatives. This offers a complementary approach to algebro-geometric solutions of integrable equations with certain advantages with respect to the use of Baker-Akhiezer functions. It has been successfully applied by Mumford et al. to the Korteweg-de Vries, Kadomtsev-Petviashvili and sine-Gordon equations. Following this approach, we construct algebro-geometric solutions to the Camassa-Holm and Dym type …
Metabolic syndrome triggered by high-fructose diet favors choroidal neovascularization and impairs retinal light sensitivity in the rat
2014
Diabetic retinopathy and age-related macular degeneration are the leading causes of blindness in Western populations. Although it is a matter of controversy, large-scale population-based studies have reported increased prevalence of age-related macular degeneration in patients with diabetes or diabetic retinopathy. We hypothesized that metabolic syndrome, one of the major risk factors for type 2 diabetes, would represent a favorable environment for the development of choroidal neovascularization, the main complication of age-related macular degeneration. The fructose-fed rat was used as a model for metabolic syndrome in which choroidal neovascularization was induced by laser photocoagulatio…
Étude des mécanismes moléculaires associés aux effets de l'ODN sur des cellules astrogliales et microgliales soumises à un stress oxydant : impact su…
2019
Neurodegenerative diseases are characterized by oxidative stress associated with mitochondrial damages leading to neuronal cell death. To mitigate these damages and promote neuronal cytoprotection and neurogenesis, endogenous (Neuropeptide: octadecaneuropeptide (ODN)) or exogenous (Polyphenols: resveratrol (RSV) and apigenin (API)) natural neurotrophic factors could be used as therapeutic agents to promote neuronal differentiation of immature and pluripotent stem cells. ODN is a peptide produced by astrocytes and known as a powerful neuroprotective agent. It is therefore of interest of studying its effects on the mobilization of calcium, its ability to protect neuronal cells against apoptos…
Docosahexaenoic acid protects human RPE cells against oxidative stress via PI3K/Akt m-TOR/p70-p85S6K pathways
2012
Purpose Oxidative Stress (OS) plays a critical role in the pathogenesis of age-related macular degeneration (AMD), especially by targeting the retinal pigment epithelium (RPE). Dietary habits with high consumption of docosahexaenoic acid (DHA) have been shown to prevent the development and evolution of AMD. Nevertheless, it is still unclear how DHA affects AMD. Our study aimed to investigate the involvement of the PI3K/Akt and m-TOR/p70-p85S6K pathways in human RPE cells after induction of OS, and then to assess the effect of DHA in the signaling pathways and in the protection against RPE cell death. Methods For this purpose, we used ARPE-19 cells exposed to the prooxidant agent, tert-butyl…