Procedimiento para la extracción de carotenoides utilizando fases líquidas nanoestructuradas

La presente invención se encuadra en el campo general de la química de productos naturales y en particular se refiere a un procedimiento para la obtención de carotenoides a partir de biomasa, y al uso de dichos productos en la industria farmacéutica y alimentaria donde los carotenoides se utilizan como suplementos nutricionales y aditivos. Los carotenoides (carotenos y xantofilas) son pigmentos naturales utilizados como aditivos alimentarios en acuicultura para la coloración de la carne de los salmónidos y como nutracéuticos y aditivos en alimentos para consumo humano. Entre los beneficios atribuidos a los carotenoides destacan su actividad antitumoral, propiedades antiinflamatorias y antidiabéticas, y su efecto protector del corazón, sistema nervioso, ojos y piel. Los carotenoides se obtienen mediante síntesis química o extracción de fuentes naturales como microalgas, levaduras y flores utilizando disolventes orgánicos. En el procedimiento propuesto se utilizan fases líquidas nanoestructuradas para la extracción y enriquecimiento de carotenoides a partir de fuentes naturales. Este procedimiento es rápido, eficaz y económico, no requiere instalaciones especiales u operaciones complicadas y proporciona productos que no contienen residuos tóxicos y, por lo tanto, pueden utilizarse en aplicaciones farmacéuticas y alimentarias

255 In vivo detection of non-occlusive thrombi in drug-eluting stents by scintigraphy and radio-labelled annexin V in a rabbit model

IntroductionThrombi in contact with non re-endothelialized stent struts associated with drug-eluting stent (DES) thrombosis. Hence, detection of thrombi in DES could help to evaluate the risk of DES thrombosis. Annexin V radio-labelled with 99mTechnetium (99mTc) is a radio-tracer with a high affinity for activated platelets.ObjectivesOur objectives were: 1) to develop an animal model of non-occlusive thrombosis of stents, 2) to evaluate the ability of annexin V 99mTc for the detection of in-stent thrombi using scintigraphy.MethodsRight carotid arteries of NZW rabbits (n=14) fed a high cholesterol diet were implanted with overlapping DES (n=7) or bare-metal stents (BMS; n=7). Four weeks after stent implantation, rabbits underwent a first scintigraphy 3 hours after injection of 200 MBq of radio-labelled annexin V 99mTc. At the end of the first scintigraphy, a suture was placed surgically proximal to the stented carotid arteries in order to induce a thrombus-prone flow limiting stenosis. Four days later, a second scintigraphy was performed. After the second scintigraphy, stents were excised, imaged ex vivo and then fixed for histological examination and scanning electron microscopy (SEM).ResultsActivities measured in vivo in the stented carotid arteries after injection of annexin V 99mTc were higher on the second scintigraphy after creation of a surgical stenosis as compared to the first scintigraphy (0.24 vs. 0.15 counts/pixel/MBq, respectively; p<0.05). On the second scintigraphy, activities were higher in DES vs. BMS (0.26 vs. 0.19 counts/pixel/MBq, respectively; p < 0.005). High activities measured in stents in vivo were associated with the detection of thrombi on corresponding histological sections and SEM.ConclusionsIn this work, we developed a rabbit model of non-occlusive thrombosis of stents in carotid arteries. In this model, in-stent thrombi could be detected using annexin V 99mTc scintigraphy

Peristrut microhemorrhages: a possible cause of in-stent neoatherosclerosis?

AbstractBackgroundIn-stent neoatherosclerosis is characterized by the delayed appearance of markers of atheroma in the subintima, but the pathophysiology underlying this new disease entity remains unclear.Methods and resultsWe collected 20 human coronary artery stents by removal from explanted hearts. The mean duration of stent implantation was 34 months. In all samples, neoatherosclerosis was detected, particularly in peristrut areas. It consisted of foam cells and cholesterol clefts, with or without calcification, associated with neovascularization. Iron and glycophorin-A were present in peristrut areas, as well as autofluorescent ceroids. Moreover, in response to neoatherosclerosis, tertiary lymphoid organs (tissue lymphoid clusters) often developed in the adventitia. Some of these features could be reproduced in an experimental carotid stenting model in rabbits fed a high-cholesterol diet. Foam cells were present in all samples, and peristrut red blood cells (RBCs) were also detected, as shown by iron deposits and Bandeiraea simplicifiola isolectin-B4 staining of RBC membranes. Finally, in silico models were used to evaluate the compliance mismatch between the rigid struts and the distensible arterial wall using finite element analysis. They show that stenting approximately doubles the local von Mises stress in the intimal layer.ConclusionsWe show here that stent implantation both in human and in rabbit arteries is characterized by local peristrut microhemorrhages and finally by both cholesterol accumulation and oxidation, triggering together in-stent neoatherosclerosis. Our data indicate that these processes are likely initiated by an increased mechanical stress due to the compliance mismatch between the rigid stent and the soft wall

In vitro and in vivo evaluation of a dextran-graft-polybutylmethacrylate copolymer coated on CoCr metallic stent

International audienceIntroduction: The major complications of stent implantation are restenosis and late stent thrombosis. PBMA polymers are used for stent coating because of their mechanical properties. We previously synthesized and characterized Dextrangraft-polybutylmethacrylate copolymer (Dex-PBMA) as a potential stent coating. In this study, we evaluated the haemocompatibility and biocompatibility properties of Dex-PBMA in vitro and in vivo.Methods: Here, we investigated: (1) the effectiveness of polymer coating under physiological conditions and its ability to release Tacrolimus®, (2) the capacity of Dex-PBMA to inhibit Staphylococcus aureus adhesion, (3) the thrombin generation and the human platelet adhesion in static and dynamic conditions, (4) thebiocompatibility properties in vitro on human endothelial colony forming cells (ECFC) and on mesenchymal stem cells (MSC) and in vivo in rat models, and (5) we implanted Dex-PBMA and Dex-PBMA TAC coated stents in neointimal hyperplasia restenosis rabbit model. Results: Dex-PBMA coating efficiently prevented bacterial adhesion and release Tacrolimus®. Dex-PBMA exhibit haemocompatibility properties under flow and ECFC and MSC compatibility. In vivo, no pathological foreign body reaction was observed neither after intramuscular nor intravascular aortic implantation. After Dex-PBMA and Dex-PBMATAC coated stents 30 days implantation in a restenosis rabbit model, an endothelial cell coverage was observed and the lumenpatency was preserved.Conclusion: Based on our findings, Dex-PBMA exhibited vascular compatibility and can potentially be used as a coating for metallic coronary stents

Effect of blasting treatment and Fn coating on MG63 adhesion and differentiation on titanium: a gene expression study using real-time RT-PCR.

Biomaterial surface properties, via alterations in the adsorbed protein layer, and the presence of specific functional groups can influence integrin binding specificity, thereby modulating cell adhesion and differentiation processes. The adsorption of fibronectin, a protein directly involved in osteoblast adhesion to the extracellular matrix, has been related to different physical and chemical properties of biomaterial surfaces. This study used blasting particles of different sizes and chemical compositions to evaluate the response of MG63 osteoblast-like cells on smooth and blasted titanium surfaces, with and without fibronectin coatings, by means of real-time reverse transcription-polymerase chain reaction (qRT-PCR) assays. This response included (a) expression of the a5, av and a3 integrin subunits, which can bind to fibronectin through the RGD binding site, and (b) expression of alkaline phosphatase (ALP) and osteocalcin (OC) as cell-differentiation markers. ALP activity and synthesis of OC were also tested. Cells on SiC-blasted Ti surfaces expressed higher amounts of the a5 mRNA gene than cells on Al2O3-blasted Ti surfaces. This may be related to the fact that SiC-blasted surfaces adsorbed higher amounts of fibronectin due to their higher surface free energy and therefore provided a higher number of specific cell-binding sites. Fn-coated Tisurfaces decreased a5 mRNA gene expression, by favoring the formation of other integrins involved in adhesion over a5b1. The changes in a5 mRNA expression induced by the presence of fibronectin coatings may moreover influence the osteoblast differentiation pathway, as fibronectin coatings on Ti surfaces also decreased both ALP mRNA expression and ALP activity after 14 and 21 days of cell culture.Peer ReviewedPostprint (published version

Carotenoids as signaling molecules in cardiovascular biology

Oxidative stress and inflammation play important roles in the etiology of cardiovascular disease (CVD). Thus, natural antioxidant carotenoids existing in fruits and vegetables could have a significant role in the prevention of CVD. Nevertheless,clinical data are conflicting about the positive effect of some antioxidant carotenoids in reducing cardiovascular morbidity and mortality. Many biological actions of carotenoids have been attributed to their antioxidant effect; however, the precise mechanism by which carotenoids produce their beneficial effects is still under discussion. They might modulate molecular pathways involved in cell proliferation, acting at Akt, tyrosine kinases, mitogen activated protein kinase (MAP kinase) and growth factor signaling cascades. Screening for a promising cardiovascular protective carotenoids therefore might be performed in vitro and in vivo with caution in cross-interaction with other molecules involved in signaling pathways especially those affecting microRNAs, performing a role in molecular modulation of cardiovascular cells

Inhibition de l'adhérence de Porphyromonas gingivalis sur la surface de titane greffé de poly(styrène sulfonate de sodium)

1 - ArticleRésumé Les infections péri-implantaires représentent l'une des causes majeures d'échec de l'ostéo-intégration des implants dentaires en titane. Ces infections sont induites par des bactéries de la flore buccale comme Porphyromonas gingivalis, dont l'adhérence sur l'implant dépend des propriétés physico-chimiques et topographiques de surface de celui-ci. À titre d'exemple, nous avons montré que la modification chimique de surfaces implantaires en titane par greffage d'un polymère " bioactif " tel que le poly(styrène sulfonate de sodium) permet de diminuer sensiblement (> 40 %) l'adhérence de Staphyloccocus aureus. L'objectif de cette étude est d'évaluer l'adhérence de Porphyromonas gingivalis sur des surfaces de titane greffées de poly(styrène sulfonate de sodium) afin d'obtenir des surfaces implantaires dotées de propriétés inhibitrices de l'adhérence de bactéries pathogènes de la flore buccale. Le greffage du poly(styrène sulfonate de sodium) sur le titane est réalisé en deux étapes : oxydation chimique du titane pour créer des espèces actives, puis greffage du poly(styrène sulfonate de sodium) par voie radicalaire. La caractérisation chimique des surfaces est réalisée par spectroscopie infrarouge à transformée de Fourier. L'adhérence bactérienne a été étudiée sur les surfaces de titane greffées et non greffées (titane contrôle), préadsorbées ou non de protéines plasmatiques. L'adsorption protéique et le comptage des bactéries sont suivis par marquage des protéines et des bactéries à la fluorescéine puis quantification par analyse d'images. Les résultats montrent que l'adsorption protéique est plus importante (~3 fois) et l'adhérence de P. gingivalis est fortement inhibée (~73 %) sur les surfaces greffées de poly(styrène sulfonate de sodium) par comparaison au titane témoin non greffé. De plus, l'inhibition de l'adhérence bactérienne observée sur les surfaces greffées et préadsorbées de protéines du plasma est comparable à celle observée sur les surfaces préadsorbées de fibronectine. En conclusion, les résultats obtenus montrent que la modification de la surface du titane par greffage poly(styrène sulfonate de sodium) conduit à une inhibition significative de l'adhérence de P. gingivalis et que cette activité inhibitrice de l'adhérence bactérienne implique l'adsorption protéique. Ces surfaces de titane greffées présentent un intérêt évident en application clinique dentaire pour le revêtement des implants. Dental implant-associated infections as peri-implantitis represent one of the major causes of osteointegration failures of oral implants. Adhesion of Porphyromonas gingivalis, one of the bacterial strains mainly involved in such infections, is tightly dependent on the topographical and/or physico-chemical properties of the implant surfaces. As a matter of fact, we showed that the grafting of one bioactive polymer such as poly(sodium styrene sulfonate) onto titanium implant surfaces allowed a sensitive decrease of Staphylococcus aureus adhesion (> 40%). The aim of the study consists in evaluating the adhesion of P. gingivalis onto titanium surfaces grafted with poly(sodium stryrene sulfonate) in order to elaborate implants exhibiting appropriate inhibiting properties towards the adhesion of periodontal pathogens. The grafting of poly(sodium stryrene sulfonate) onto titanium surfaces is carried out in two steps: chemical oxydation of titanium to initiate radical species then grafting of poly(sodium stryrene sulfonate) by radical polymerization. Chemical characterization of the surfaces is achieved by Fourier transformed infrared spectroscopy (FTIR). Bacterial adhesion was studied on grafted and non grafted (control) titanium surfaces, preadsorbed or not by plasmatic proteins. Protein adsorption as well as bacteria adhesion is followed by fluorescence spectroscopy by using proteins or bacteria previously labelled with fluorescence probes; the quantification of adsorption and bacteria adhesion are performed by image analysis. Results showed that protein adsorption is more important (~3 times) and that P. gingivalis adhesion is strongly inhibited (~73%) onto poly(sodium styrene sulfonate) grafted surfaces when compared to titanium control. Moreover, the inhibition of bacterial adhesion on grafted surfaces preadsorbed with plasma proteins is comparable to that observed on grafted surfaces preadsorbed with fibronectin. In conclusion, the obtained results evidenced that the grafting of titanium surface by poly(sodium styrene sulfonate) led to significant inhibition of P. gingivalis adhesion and that this inhibitory activity involved adsorbed proteins. Poly(sodium styrene sulfonate) grafted titanium surfaces present a high interest for the elaboration of oral implants in various clinical dental applications

Inhibition of Staphylococcus epidermidis adhesion on titanium surface with bioactive water-soluble copolymers bearing sulfonate, phosphate or carboxylate functions

1 - ArticleImplanted prostheses are sometimes subject to bacterial infections, which can threat their benefit rule on a long-term basis. Various methods are studied to fight against these infections. Among them, the grafting of bioactive polymers onto the prosthesis surface shows up as a promising way to the problem of infections. This work presents the influence of various water-soluble bioactive polymers on the inhibition of the Staphylococcus epidermidis adhesion on the titanium samples surfaces initially preadsorbed with various proteins. Whatever the studied protein is, it is shown that the bioactive polymer containing sulfonate functions generates an inhibition of the adhesion of Staphylococcus epidermidis. For a plasma preadsorption, the inhibition rate rises up to 68% when the concentration of sulfonate function is 2.5 mu mol/L. Titanium surfaces grafted with the bioactive polymer were also tested. We find an inhibitive activity of the adhesion close to that of the previous case. These preliminary results can point up a clinical interest in the fight against the medical devices infection, because they highlight a clear local effect of S. epidermidis adhesion inhibition. Copolymers containing other functional groups (phosphate or carboxylate) were dissolved in a bacterial suspension to monitor the influence of the composition on the adhesion inhibition. Their inhibition rates are not significantly lower than those of pNaSS homopolymers, as much as the sulfonate function proportion remains higher than 50%. Thus, the sulfonate function is the main responsible for the inhibition of the S. epiderrnidis adhesion. (C) 2010 Elsevier Masson SAS. All rights reserved