Nanoparticles Target Resistant Parasites

Drug therapies for the parasitic infection African trypanosomiasis, or sleeping sickness, have long had problems with high toxicity. These drugs must be administered in a hospital because of the likelihood of brain swelling and other reactions. In addition, many parasite strains have developed resistance by evolving altered transport proteins that keep the drugs out of their cells. But Spanish scientists may have discovered a way to address both problems with a novel formulation of the antiparasite drug pentamidine (PLOS Pathog. 2015, DOI: 10.1371/journal.ppat.1004942). By preparing a pentamidine-loaded chitosan nanoparticle that enters the parasite through endocytosis instead of through membrane transport, a team led by the University of Granada’s José A. Garcia-Salcedo was able to lower the curative dose of pentamidine in mouse models to 1% of the normal dose. Even mice infected with resistant parasite strains lived significantly longer when treated with the nanoparticles than with free pentamidine. “This is a very intriguing paper in which the formulation of an existing drug is altered to improve treatment rather than screening for new drug entities,” says tropical disease pathologist James McKerrow of the University of California, San Diego.