PLA-PEG Nanoparticles Improve the Anti-Inflammatory Effect of Rosiglitazone on Macrophages by Enhancing Drug Uptake Compared to Free Rosiglitazone

Among cardiovascular diseases, atherosclerosis remains the first cause of death in the United States of America and Europe, as it leads to myocardial infarction or stroke. The high prevalence of heart diseases is due to the difficulty in diagnosing atherosclerosis, since it can develop for decades before symptoms occur, and to the complexity of the treatment since targets are also important components of the host defenses. The antidiabetics thiazolidinediones, among which is rosiglitazone (RSG), have demonstrated anti-atherosclerotic effect in animal models, and are therefore promising candidates for the improvement of atherosclerosis management. Nevertheless, their administration is hindered by the insurgence of severe side effects. To overcome this limitation, rosiglitazone has been encapsulated into polymeric nanoparticles, which permit efficient delivery to its nuclear target, and selective delivery to the site of action, allowing the reduction of unwanted effects. In the present work, we describe nanoparticle formulation using polylactic acid (PLA) coupled to polyethylene glycol (PEG), their characterization, and their behavior on RAW264.7 macrophages, an important target in atherosclerosis treatment. RSG nanocarriers showed no toxicity on cells at all concentrations tested, an anti-inflammatory effect in a dose-dependent manner, up to 5 times more efficient than the free molecule, and an increased RSG uptake which is consistent with the effect shown. These biodegradable nanoparticles represent a valid tool to be further investigated for the treatment of atherosclerosis

Ultrasound-induced mild hyperthermia improves the anticancer efficacy of both Taxol® and paclitaxel-loaded nanocapsules

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Formulation and Pharmacokinetics of Thermosensitive Stealth® Liposomes Encapsulating 5-Fluorouracil

International audiencePURPOSE:We optimize the encapsulation and investigate the pharmacokinetics of 5-Fluorouracil (5-FU) delivered by thermosensitive stealth(®) liposomes (TSLs) designed to trigger drug release upon hyperthermia using focused ultrasound (FUS).METHODS:5-FU was encapsulated into liposomes made of 1,2-Dipalmitoyl-sn-glycero-3-phosphocholine/cholesterol/1,2-Distearoyl-sn-glycero-3-phosphoethanolamine-N-PEG2000 either as a free molecule or complexed with copper-polyethylenimine. Heat-triggered drug release was evaluated using either a water bath or FUS. Formulation cytotoxicity was assessed on HT-29 cell line by MTS assay. Pharmacokinetics and biodistribution of 5-FU were evaluated in HT-29-tumor bearing mice.RESULTS:5-FU was easily encapsulated using the lipid hydration method (encapsulation efficacy of 13%) but poorly retained upon dilution. 5-FU complexation with copper-polyethylenimine improved 5-FU retention into liposomes and allowed to obtain an encapsulation efficacy of 37%. At 42°C, heat-triggered 5-FU release from TSLs was 63% using a water bath and 68% using FUS, within 10 min, whereas it remained below 20% for the non-thermosensitive formulation. The MTS assay revealed that formulation toxicity arose from 5-FU and not from the excipients. In addition, 5-FU complex encapsulation into TSLs induces a reduction of the IC50 from 115 down to 49 μM. Pharmacokinetics reveals a longer circulation of encapsulated 5-FU and a more important body exposure, although tumor passive targeting is not significantly higher than free 5-FU.CONCLUSIONS:Complexation of 5-FU with copper-polyethylenimine appears an interesting strategy to improve 5-FU retention into TSLs in vitro and in vivo. TSLs allow heat-triggered release of the drug within 10 min at 42°C, a reasonable time for future in vivo experiments

ABCG2 and ABCG4-Mediated Efflux of Amyloid-β Peptide 1-40 at the Mouse Blood-Brain Barrier.

International audienceThe accumulation of amyloid-β peptide (Aβ) in the brain is a critical hallmark of Alzheimer's disease. This high cerebral Aβ concentration may be partly caused by impaired clearance of Aβ across the blood-brain barrier (BBB). The low-density lipoprotein receptor-related protein-1 (LRP-1) and the ATP-binding cassette (ABC) protein ABCB1 (P-glycoprotein) are involved in the efflux of Aβ across the BBB. We hypothesized that other ABC proteins, such as members of the G subfamily, are also involved in the BBB clearance of Aβ. We therefore investigated the roles of ABCG2 (BCRP) and ABCG4 in the efflux of [3H] Aβ1-40 from HEK293 cells stably transfected with human ABCG2 or mouse abcg4. We showed that ABCG2 and Abcg4 mediate the cellular efflux of [3H] Aβ1-40. In addition, probucol fully inhibited the efflux of [3H] Aβ1-40 from HEK293-abcg4 cells. Using the in situ brain perfusion technique, we showed that GF120918 (dual inhibitor of Abcb1 and Abcg2) strongly enhanced the uptake (Clup, μl/g/s) of [3H] Aβ1-40 by the brains of Abcb1-deficient mice, but not by the brains of Abcb1/Abcg2-deficient mice, suggesting that Abcg2 is involved in the transport of Aβ at the mouse BBB. Perfusing the brains of Abcb1/Abcg2- and Abca1-deficient mice with [3H] Aβ1-40 plus probucol significantly increased the Clup of Aβ. This suggests that a probucol-sensitive transporter that is different from Abca1, Abcb1, and Abcg2 is involved in the brain efflux of Aβ. We suggest that this probucol-sensitive transporter is Abcg4. We conclude that Abcg4 acts in concert with Abcg2 to efflux Aβ from the brain across the BBB

Towards an Improved anti-HIV Activity of NRTI via Metal-Organic Frameworks Nanoparticles

Nanoscale mesoporous iron carboxylates metal-organic frameworks (nanoMOFs) have recently emerged as promising platforms for drug delivery, showing biodegradability, biocompatibility and important loading capability of challenging highly water-soluble drugs such as azidothymidine tryphosphate (AZT-TP). In this study, nanoMOFs made of iron trimesate (MIL-100) were able to act as efficient molecular sponges, quickly adsorbing up to 24 wt% AZT-TP with entrapment efficiencies close to 100%, without perturbation of the supramolecular crystalline organization. These data are in agreement with molecular modelling predictions, indicating maximal loadings of 33 wt% and preferential location of the drug in the large cages. Spectrophotometry, isothermal titration calorimetry, and solid state NMR investigations enable to gain insight on the mechanism of interaction of AZT and AZT-TP with the nanoMOFs, pointing out the crucial role of phosphates strongly coordinating with the unsaturated iron(III) sites. Finally, contrarily to the free AZT-TP, the loaded nanoparticles efficiently penetrate and release their cargo of active triphosphorylated AZT inside major HIV target cells, efficiently protecting against HIV infection