by Keyword: Antimalarial drugs

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Borgheti-Cardoso, L. N., Kooijmans, S. A. A., Gutiérrez Chamorro, L., Biosca, A., Lantero, E., Ramírez, M., Avalos-Padilla, Y., Crespo, I., Fernández, I., Fernandez-Becerra, C., del Portillo, H. A., Fernàndez-Busquets, X., (2020). Extracellular vesicles derived from Plasmodium-infected and non-infected red blood cells as targeted drug delivery vehicles International Journal of Pharmaceutics 587, 119627

Among several factors behind drug resistance evolution in malaria is the challenge of administering overall doses that are not toxic for the patient but that, locally, are sufficiently high to rapidly kill the parasites. Thus, a crucial antimalarial strategy is the development of drug delivery systems capable of targeting antimalarial compounds to Plasmodium with high specificity. In the present study, extracellular vesicles (EVs) have been evaluated as a drug delivery system for the treatment of malaria. EVs derived from naive red blood cells (RBCs) and from Plasmodium falciparum-infected RBCs (pRBCs) were isolated by ultrafiltration followed by size exclusion chromatography. Lipidomic characterization showed that there were no significant qualitative differences between the lipidomic profiles of pRBC-derived EVs (pRBC-EVs) and RBC-derived EVs (RBC-EVs). Both EVs were taken up by RBCs and pRBCs, although pRBC-EVs were more efficiently internalized than RBC-EVs, which suggested their potential use as drug delivery vehicles for these cells. When loaded into pRBC-EVs, the antimalarial drugs atovaquone and tafenoquine inhibited in vitro P. falciparum growth more efficiently than their free drug counterparts, indicating that pRBC-EVs can potentially increase the efficacy of several small hydrophobic drugs used for the treatment of malaria.

Keywords: Antimalarial drugs, Drug delivery, Extracellular vesicles, Malaria, Plasmodium falciparum

Lantero, E., Fernandes, J., Aláez-Versón, C. R., Gomes, J., Silveira, H., Nogueira, F., Fernàndez-Busquets, X., (2020). Heparin administered to anopheles in membrane feeding assays blocks plasmodium development in the mosquito Biomolecules 10, (8), 1136

Innovative antimalarial strategies are urgently needed given the alarming evolution of resistance to every single drug developed against Plasmodium parasites. The sulfated glycosaminoglycan heparin has been delivered in membrane feeding assays together with Plasmodium berghei-infected blood to Anopheles stephensi mosquitoes. The transition between ookinete and oocyst pathogen stages in the mosquito has been studied in vivo through oocyst counting in dissected insect midguts, whereas ookinete interactions with heparin have been followed ex vivo by flow cytometry. Heparin interferes with the parasite’s ookinete–oocyst transition by binding ookinetes, but it does not affect fertilization. Hypersulfated heparin is a more efficient blocker of ookinete development than native heparin, significantly reducing the number of oocysts per midgut when offered to mosquitoes at 5 µg/mL in membrane feeding assays. Direct delivery of heparin to mosquitoes might represent a new antimalarial strategy of rapid implementation, since it would not require clinical trials for its immediate deployment.

Keywords: Anopheles, Antimalarial drugs, Heparin, Malaria, Mosquito, Ookinete, Plasmodium, Transmission blocking

Martí Coma-Cros, E., Biosca, A., Marques, J., Carol, L., Urbán, P., Berenguer, D., Riera, M. C., Delves, M., Sinden, R. E., Valle-Delgado, J. J., Spanos, L., Siden-Kiamos, I., Pérez, P., Paaijmans, K., Rottmann, M., Manfredi, A., Ferruti, P., Ranucci, E., Fernàndez-Busquets, X., (2018). Polyamidoamine nanoparticles for the oral administration of antimalarial drugs Pharmaceutics 10, (4), 225

Current strategies for the mass administration of antimalarial drugs demand oral formulations to target the asexual Plasmodium stages in the peripheral bloodstream, whereas recommendations for future interventions stress the importance of also targeting the transmission stages of the parasite as it passes between humans and mosquitoes. Orally administered polyamidoamine (PAA) nanoparticles conjugated to chloroquine reached the blood circulation and cured Plasmodium yoelii-infected mice, slightly improving the activity of the free drug and inducing in the animals immunity against malaria. Liquid chromatography with tandem mass spectrometry analysis of affinity chromatography-purified PAA ligands suggested a high adhesiveness of PAAs to Plasmodium falciparum proteins, which might be the mechanism responsible for the preferential binding of PAAs to Plasmodium-infected erythrocytes vs. non-infected red blood cells. The weak antimalarial activity of some PAAs was found to operate through inhibition of parasite invasion, whereas the observed polymer intake by macrophages indicated a potential of PAAs for the treatment of certain coinfections such as Plasmodium and Leishmania. When fluorescein-labeled PAAs were fed to females of the malaria mosquito vectors Anopheles atroparvus and Anopheles gambiae, persistent fluorescence was observed in the midgut and in other insect’s tissues. These results present PAAs as a versatile platform for the encapsulation of orally administered antimalarial drugs and for direct administration of antimalarials to mosquitoes, targeting mosquito stages of Plasmodium.

Keywords: Anopheles, Antimalarial drugs, Malaria, Mosquitoes, Nanomedicine, Nanotechnology, Plasmodium, Polyamidoamines, Polymers, Targeted drug delivery

Aláez-Versón, C. R., Lantero, E., Fernàndez-Busquets, X., (2017). Heparin: New life for an old drug Nanomedicine 12, (14), 1727-1744

Heparin is one of the oldest drugs, which nevertheless remains in widespread clinical use as an inhibitor of blood coagulation. The history of its identification a century ago unfolded amid one of the most fascinating scientific controversies turning around the distribution of credit for its discovery. The composition, purification and structure-function relationship of this naturally occurring glycosaminoglycan regarding its classical role as anticoagulant will be dealt with before proceeding to discuss its therapeutic potential in, among other, inflammatory and infectious disease, cancer treatment, cystic fibrosis and Alzheimer's disease. The first bibliographic reference hit using the words 'nanomedicine' and 'heparin' is as recent as 2008. Since then, nanomedical applications of heparin have experienced an exponential growth that will be discussed in detail, with particular emphasis on its antimalarial activity. Some of the most intriguing potential applications of heparin nanomedicines will be exposed, such as those contemplating the delivery of drugs to the mosquito stages of malaria parasites.

Keywords: Anopheles, Antimalarial drugs, Heparin, Malaria, Mosquitoes, Nanomedicine, Nanotechnology, Plasmodium, Targeted drug delivery

Fernàndez-Busquets, X., (2016). Novel strategies for Plasmodium-targeted drug delivery Expert Opinion on Drug Delivery , 13, (7), 919-922