Contribution of Cholesterol and Oxysterols in the Physiopathology of Cataract: Implication for the Development of Pharmacological Treatments

The development of cataract is associated with some lipid changes in human lens fibers, especially with increased accumulation and redistribution of cholesterol inside these cells. Some direct and indirect lines of evidence, also suggest an involvement of cholesterol oxide derivatives (also named oxysterols) in the development of cataract. Oxysterol formation can result either from nonenzymatic or enzymatic processes, and some oxysterols can induce a wide range of cytotoxic effects (overproduction of reactive oxygen species (ROS); phospholipidosis) which might contribute to the initiation and progression of cataract. Thus, the conception of molecules capable of regulating cholesterol homeostasia and oxysterol levels in human lens fibers can have some interests and constitute an alternative to surgery at least at early stages of the disease

EFEKTIVITAS PROGRAM PEMBERDAYAAN MASYARAKAT MISKIN DI KELURAHAN PAAL DUA KECAMATAN PAAL DUA KOTA MANADO

AbstrakPemberdayaan masyarakat pada dasarnya bertujuan mewujudkan kesejahteraan, kedaulatan dan kemandirian, kesejahteraan tercemin dari peningkatan kualitas hidup lahir batin dan kemampuan masyarakat untuk memenuhi kebutuhan dasarnya, terutama di bidang ekonomi, pendidikan dan kesehatan, kedaulatan terbentuk dari derajat partisipasi yang mampu dilakukan masyarakat dalam pengambilan keputusan pembangunan, sedangkan kemandirian terwujud dari kemampuan swadaya dan gotong-royong masyarakat untuk mencukupi kebutuhan sendiri melalui pendayagunaan segenap potensi baik sumber daya alam, sumber daya manusia, kelembagaan masyarakat, modal finansial, maupun modal sosial yang ada. Tujuan penelitian ini adalah untuk mengetahui efektivitas program pemberdayaan masyarakat di Kelurahan Paal Dua Kecamatan Paal Dua Kota Manado, dengan menggunakan metode penelitian kualitatif diharapkan penelitian ini dapat menjawab secara paripurna mengenai masalah yang diteliti, hasil penelitian menunjukkan bahwa secara umum efektivitas pelaksanaan program pemberdayaan masyarakat miskin di Kelurahan Paal Dua yang dalam hal ini menjadi tanggung jawab dan wewenang pemerintah kelurahan bisa dikatakan kurang efektif, hal ini ditunjukkan dari kendala yang dihadapi yaitu pemahaman program kepada masyarakat yang dilakukan oleh pemerintah kelurahan belum berhasil dengan baik, karena proses sosialisasi program pemberdayaan seperti kelompok usaha bersama hanya dilakukan satu kali dengan alasan tidak tersedianya anggaran untuk melakukan sosialsiasi untuk memberikan pemahaman kepada masyarakat tersebut.Kata Kunci: Efektivitas, Program, Pemberdayaan Masyarakat Miskin

Implication de l'acide docosanoïque (C22 0) et des acides gras à très longue chaîne (acide tétracosanoïque (C24 0), acide hexacosanoïque ( C26 0) dans la maladie d'Alzheimer (aspects biologiques et cliniques)

Au niveau du cerveau et dans le plasma de malades atteints de maladie d Alzheimer (MA), l accumulation de C22:0 et d acides gras à très longue chaîne (C24:0 ; C26:0), la diminution d acide docosahexaenoique (C22:6 n-3) et les modifications quantitatives et qualitatives de plasmalogènes suggèrent l implication de dysfonctions peroxysomales. En fonction de ces constatations, les activités biologiques de C22:0, C24:0 et C26:0 ont été recherchées sur des cellules neuronales humaines SK-N-BE. La lipotoxicité des acides gras (C22:0, C24:0 et C26:0) induit divers effets au niveau des mitochondries (modifications topographiques, morphologiques et fonctionnelles), conduit à une rupture de l équilibre RedOx (surproduction d espèces radicalaires de l oxygène, modification de l activité des enzymes anti-oxydantes : catalase, SOD, GPx), à une peroxydation lipidique et à une désorganisation du cytosquelette (microfilaments d actine, tubuline, neurofilaments). Ces acides affectent aussi l amyloïdogenèse et la tauopathie. L amyloïde béta favorise aussi l accumulation intracellulaire de C22:0, C24:0 et C26:0. A fortes concentrations, ces acides gras induisent une mort cellulaire non apoptotique. Par ailleurs, les données immunohistochimiques en relation avec l expression de marqueurs peroxysomaux (ABCD1, ABCD2, ABCD3, ACOX1 et catalase) au niveau du cerveau de souris transgéniques APP PS1 E9 ainsi que les profil d acide gras obtenus sur le cerveau et le sang de ces souris suggèrent qu elles pourraient constituer un bon modèle pour l étude des relations entre MA et métabolisme peroxysomal. L étude clinique réalisée sur plasma et érythrocytes de malades déments (MA, démences vasculaires, autres démences) montre une forte accumulation de C22:0, C24:0 et C26:0. Le C26:0 pourrait constituer un excellent biomarqueur de la MA. Le C18:0 à est aussi augmenté ainsi que les acides gras n-6. De forts indices de stress oxydant sont aussi révélés. Dans son ensemble, le travail réalisé suggère que les acides gras (C22:0, C24:0 et C26:0) ainsi que le métabolisme des acides gras en relation avec le métabolisme peroxysomal pourraient contribuer à la neurodégénéréscence associée aux démences incluant la MAIn the brain and in the plasma of patients with Alzheimer s disease (AD), marked accumulation of C22:0 and of very long chain fatty acids (C24:0 ; C26:0) have been reported. Important decreases of docosahexaenoic acid (DHA; C22:6 n-3) have also been described as well as quantitative and qualitative modifications of plasmalogens. Altogether, these lipid modifications suggest an implication of peroxisomal metabolism disorders in the physiopathology of AD. Therefore, the biological activities of C22:0, C24:0 and C26:0 have been studied on human neuronal cells SK-N-BE. On these cells, the lipotoxicity of fatty acids (C22:0, C24:0 and C26:0) leads to various cellular modifications: topographical, morphological and functional changes at the mitochondrial level, rupture of RedOx equilibrium (overproduction of reactive oxygen species, modification of the activity of enzymes involved in anti-oxidant defenses: catalase, SOD, GPx), lipid peroxidation, cytoskeleton disorganization (actin microfilaments, tubulin, neurofilaments). These fatty acids also favor amyloidogenesis and tauopathy. At elevated concentrations, these fatty acids trigger a non apoptotic mode of cell death. Moreover, data obtained by immunohistochemistry with antibodies raised against peroxisomal components (ABCD1, ABCD2, ABCD3, ACOX1 and catalase) on histological tissue sections of the brain of transgenic mice APP PS1 E9 as well as lipidomic analysis performed on the blood and the brain of these mice suggest that they could constitute interesting model to study the relationships between AD and peroxisomal metabolism. The clinical study performed on the plasma and on the erythrocytes of patients with dementia (AD, vascular dementia, other dementia) revealed an important accumulation of C22:0, C24:0 and C26:0. Hexacosanoic acid (C26:0) might constitute an excellent biomarker of AD. The fatty acid C18:0 and (n-6) fatty acids have also been found at increased concentrations. A strong oxidative stress has also been revealed. Altogether, our data support that the fatty acids (C22:0, C24:0 and C26:0) as well as the fatty acid metabolism depending on the peroxisome might contribute to neurodegeneration leading to various types of dementia including ADDIJON-BU Doc.électronique (212319901) / SudocSudocFranceF

11 beta-Hydroxysteroid dehydrogenase type 1 contributes to the regulation of 7-oxysterol levels in the arterial wall through the inter-conversion of 7-ketocholesterol and 7 beta-hydroxycholesterol

AbstractThe atherogenic 7-oxysterols, 7-ketocholesterol (7-KC) and 7β-hydroxycholesterol (7βOHC), can directly impair arterial function. Inter-conversion of 7-KC and 7βOHC has recently been shown as a novel role for the glucocorticoid-metabolizing enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1). Since this enzyme is expressed in vascular smooth muscle cells, we addressed the hypothesis that inter-conversion of 7-KC and 7βOHC by 11β-HSD1 may contribute to regulation of arterial function.Incubation (4–24 h) of aortic rings with either 7-KC (25 μM) or 7βOHC (20 μM) had no effect on endothelium-dependent (acetylcholine) or -independent (sodium nitroprusside) relaxation. In contrast, exposure to 7-KC (but not to 7βOHC) attenuated noradrenaline-induced contraction (Emax) after 4 h (0.78 ± 0.28 vs 0.40 ± 0.08 mN/mm; p < 0.05) and 24 h (2.28 ± 0.34 vs 1.56 ± 0.48 mN/mm; p < 0.05). Both 7-oxysterols were detected by GCMS in the aortic wall of chow-fed C57Bl6/J mice, with concentrations of 7-KC (1.41 ± 0.81 ng/mg) higher (p = 0.05) than 7βOHC (0.16 ± 0.06 ng/mg). In isolated mouse aortic rings 11β-HSD1 was shown to act as an oxo-reductase, inter-converting 7-KC and 7βOHC. This activity was lost in aorta from 11β-HSD1−/− mice, which had low oxysterol levels. Renal homogenates from 11β-HSD1−/− mice were used to confirm that the type 2 isozyme of 11β-HSD does not inter-convert 7-KC and 7βOHC.These results demonstrate that 7-KC has greater effects than 7βOHC on vascular function, and that 11β-HSD1 can inter-convert 7-KC and 7βOHC in the arterial wall, contributing to the regulation of 7-oxysterol levels and potentially influencing vascular function. This mechanism may be important in the cardioprotective effects of 11β-HSD1 inhibitors

Brain Peroxisomes

Peroxisomes are essential organelles in higher eukaryotes as they play a major role in numerous metabolic pathways and redox homeostasis. Some peroxisomal abnormalities, which are often not compatible with life or normal development, were identified in severe demyelinating and neurodegenerative brain diseases. The metabolic roles of peroxisomes, especially in the brain, are described and human brain peroxisomal disorders resulting from a peroxisome biogenesis or a single peroxisomal enzyme defect are listed. The brain abnormalities encountered in these disorders (demyelination, oxidative stress, inflammation, cell death, neuronal migration, differentiation) are described and their pathogenesis are discussed. Finally, the contribution of peroxisomal dysfunctions to the alterations of brain functions during aging and to the development of Alzheimer's disease is considered

Toxicological Risk Assessment of Emerging Nanomaterials: Cytotoxicity, Cellular Uptake, Effects on Biogenesis and Cell Organelle Activity, Acute Toxicity and Biodistribution of Oxide Nanoparticles

The lack of toxicological data on nanomaterials makes it difficult to assess the risk related to their exposure, and as a result further investigation is required. This chapter presents the synthesis of controlled oxide nanoparticles followed by the evaluation of their safety profile or toxicity (iron, titanium and zinc oxides). The controlled surface chemistry, dispersion in several media, morphology and surface charge of these nanoparticles are presented (transmission electron microscopy, dynamic light scattering, zeta potential, X-ray photoelectron spectroscopy). Classical cytotoxic and cellular uptake studies on different cancer cell lines from liver, prostate, heart, brain and spinal cord are discussed. The incidence of nanoparticles on biogenesis and activity of cell organelles is also highlighted, as well as their biodistribution in animal models. The acute toxicity on zebrafish embryo model is also presented. Finally, the stress is put on the influence and the necessity of controlling the protein corona, a layer of plasma proteins physically adsorbed at the surface of such nanoparticles as a result of their presence in the bloodstream (or relevant biological fluids)

Recommandations préanalytiques pour les analyses de protéomique clinique des fluides biologiques

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