INVESTIGADORES
MORILLA Maria Jose
congresos y reuniones científicas
Título:
Killing it softly ?with lipids: on the new lethal topical vesicles against protozoa and fungi
Autor/es:
ROMERO, MORILLA
Reunión:
Conferencia; CLINAM 2013; 2013
Resumen:
The protozoa Leishmania braziliensis is the etiological agent of muco cutaneous leishmaniasis, an endemic zoonotic disease in South America that infects skin macrophages to end up destroying epithelial and mucosa tissue. The parasite is capable of taking up particulate material of size in the order of plasma proteins (< 10 nm diameter) by the flagellar pocket (FP). This type of endocytic uptake is limited to a small area (3 %) of the parasite body and seems to offers a steric restriction for the uptake of higher sized particulate material.  The uptake of particulate material by fungi such as Candida spp on the other hand, is much less explored, but a similar steric constraint would be present. The penetration of particulate material across the intact skin is another example of steric restriction to be surpassed by vesicles that have to displace across hydrophilic nanochannels of less than 10 nm diameter. Our laboratory has developed different antifungal and antileishmania therapeutic and prophylactic strategies, by exploiting the sterically constrained endocytic uptake of parasites that colonize the skin surface and deeper layers combined with the high deformability of specially designed lipid nanovesicles. In this context we have found that in spite of their high size (~100 nm diameter) deformable nanovesicles have anti-protozoa activity per se and that if used for non occlusive topical delivery of anti mycotic, photodynamic agents to intracellular amastigotes or antigenic material to cells of the skin immune system, are more effective than their non deformable counterparts of similar size. Against Candida albicans and Candida parapsilopsis for instance, special deformable vesicles containing Amphotericin B have 33 and 8 folds lower MIC than Fungizone respectively, and 4 folds lower MIC than Ambisome. A low fluence rate of 0,2 J/cm2 on ultra low doses of photodynamic deformable vesicles at 0,01 mM ZnPC are capable of eliminating intracellular amastigotes of Leishmania braziliensis without killing host macrophages. In vivo, the same formulations substantially reduced the size of lesions in Swiss mice after 5 doses plus 30 minutes of sunlight irradiation. Finally, the topical application of a leishmania cell lysate within deformable nanovesicles targeted against skin macrophages on the intact skin of Balb c mice, produced antigen-specific systemic responses mediated by the induction of the pro-inflammatory cytokines TNFa and IL6. Remarkably, these results show that vesicles with special elasto mechanical properties can be used not only to replace injectables but also to be efficiently taken up by the complex endocytic machinery of eukaryotic pathogens.