by Keyword: Red blood cell

By year:[ 2018 | 2017 | 2016 | 2015 | 2014 | 2013 | 2012 | 2011 | 2010 | 2009 | 2008 | 2007 | 2006 | 2005 ]

Moles, E., Fernàndez-Busquets, X., (2015). Loading antimalarial drugs into noninfected red blood cells: An undesirable roommate for Plasmodium Future Medicinal Chemistry 7, (7), 837-840

The malaria parasite, Plasmodium spp., is a delicate unicellular organism unable to survive in free form for more than a couple of minutes in the bloodstream. Upon injection in a human by its Anopheles mosquito vector, Plasmodium sporozoites pass through the liver with the aim of invading hepatocytes. Those which succeed spend inside their host cell a recovery time before replicating and entering the blood circulation as fragile merozoites, although their exposure to host defenses is extraordinarily short. Quick invasion of red blood cells (RBCs) in a process lasting just a few minutes allows the parasite to escape immune system surveillance. For most of its erythrocytic cycle the pathogen feeds mainly on hemoglobin as it progresses from the early blood stages, termed rings, to the late forms trophozoites and schizonts. Early stages are ideal targets for antimalarial therapies because drugs delivered to them would have a longer time to kill the parasite before it completes its development. However, only 6 h after invasion does the permeability of the infected erythrocyte to anions and small nonelectrolytes, including some drugs, start to increase as the parasite matures [1]. During this maturation process the parasite hydrolyzes hemoglobin in a digestive vacuole, which is the target of many amphiphilic drugs that freely cross the RBC membrane and accumulate intracellularly. As a result, most antimalarials start affecting the infected cell relatively late in the intraerythrocytic parasite life cycle, when their effect is probably often too short to be lethal to Plasmodium.

Keywords: Malaria, Nanomedicine, Plasmodium, Red blood cell, Targeted drug delivery

Marques, J., Moles, E., Urbán, P., Prohens, R., Busquets, M. A., Sevrin, C., Grandfils, C., Fernàndez-Busquets, X., (2014). Application of heparin as a dual agent with antimalarial and liposome targeting activities toward Plasmodium-infected red blood cells Nanomedicine: Nanotechnology, Biology, and Medicine 10, (8), 1719-1728

Heparin had been demonstrated to have antimalarial activity and specific binding affinity for Plasmodium-infected red blood cells (pRBCs) vs. non-infected erythrocytes. Here we have explored if both properties could be joined into a drug delivery strategy where heparin would have a dual role as antimalarial and as a targeting element of drug-loaded nanoparticles. Confocal fluorescence and transmission electron microscopy data show that after 30. min of being added to living pRBCs fluorescein-labeled heparin colocalizes with the intracellular parasites. Heparin electrostatically adsorbed onto positively charged liposomes containing the cationic lipid 1,2-dioleoyl-3-trimethylammonium-propane and loaded with the antimalarial drug primaquine was capable of increasing three-fold the activity of encapsulated drug in Plasmodium falciparum cultures. At concentrations below those inducing anticoagulation of mouse blood in vivo, parasiticidal activity was found to be the additive result of the separate activities of free heparin as antimalarial and of liposome-bound heparin as targeting element for encapsulated primaquine. From the Clinical Editor: Malaria remains an enormous global public health concern. In this study, a novel functionalized heparin formulation used as drug delivery agent for primaquine was demonstrated to result in threefold increased drug activity in cell cultures, and in a murine model it was able to provide these benefits in concentrations below what would be required for anticoagulation. Further studies are needed determine if this approach is applicable in the human disease as well.

Keywords: Heparin, Liposomes, Malaria, Plasmodium, Targeted drug delivery, Heparin, Malaria, Plasmodium, Red blood cell, Targeted drug delivery, Liposomes, 1,2 dioleoyl 3 trimethylammoniopropane, fluorescein, heparin, liposome, nanoparticle, primaquine, adsorption, animal experiment, anticoagulation, antimalarial activity, Article, binding affinity, confocal microscopy, controlled study, drug targeting, encapsulation, erythrocyte, female, fluorescence microscopy, human, human cell, in vivo study, liposomal delivery, mouse, nonhuman, Plasmodium falciparum, transmission electron microscopy

Castillo-Fernandez, O., Rodriguez-Trujillo, R., Gomila, G., Samitier, J., (2014). High-speed counting and sizing of cells in an impedance flow microcytometer with compact electronic instrumentation Microfluidics and Nanofluidics 16, (1-2), 91-99

Here we describe a high-throughput impedance flow cytometer on a chip. This device was built using compact and inexpensive electronic instrumentation. The system was used to count and size a mixed cell sample containing red blood cells and white blood cells. It demonstrated a counting capacity of up to ~500 counts/s and was validated through a synchronised high-speed optical detection system. In addition, the device showed excellent discrimination performance under high-throughput conditions.

Keywords: Electronics, Impedance, Microcytometry, Microfluidics, Red blood cells (RBCs), White blood cells (WBCs)