New Insights on Multifunctional Nano-platform Against Cutaneous Leishmaniasis

HIGA LH, MONTANARI JA, SCHILRREFF P., RONCAGLIA D, MORILLA MJ AND ROMERO EL.

Basilea

Conferencia; 3rd European Conference for Clinical Nanomedicine; 2010

European Foundation for Clinical Nanomedicine

Our laboratory has developed the concept of multifunctional platform for the treatment of cutaneous leishmaniasis, as UltraDeformable archaeosomes (UDa) made of ([Total polar lipids from extremely halophilic Halorubrum tebenquichense non alkaliphilic strain, plus carotenoids, retinal and bacterioruberin]: soy Pc: sodium cholate 3:3:1 w/w) loaded with a hydrophobic Zn phtalocyanine as a sunlight triggered photodynamic agent, or with a model protein ovoalbumine (OVA), for topical immunization. We have found that UDa-ZnPc (1.25 mM ZnPc-1 mM phospholipids) elicited 100 % anti- Leishmania braziliensis promastigote activity (APA) as well as 80 % anti amastigote activity (AA) after only 15 min sunlight irradiation (15 J/cm2). Surprisingly empty UDa and UDa-ZnPc also showed an extensive non-photodynamic leishmanicidal activity. Remarkably, the phagocytosis of UDa-ZnPc by infected host cells (and not the simple diffusion of free ZnPc) probably led to products of ZnPc metabolization that were innocuous for the host but lethal for the parasites, even in the dark. This means that in the absence of host cells toxicity (apoptosis/oxidative stress by GSH consumption, release of lactate dehydrogenase, MTT) minor doses of empty UDa or UDa-ZnPc had got a fast and deeply in vitro destructive effect against the extra and intracellular forms of the leishmania parasites, which is accelerated but not triggered by sunlight irradiation. On the other hand, two levels of OVA (0.3 mgOVA/ 0.6mg phospholipids and 0.6mg OVA/ 0.6 mg phospholipids)/ were applied as OVA-UDa on an area of 2 cm2 in non shaved nor stripped Balb/c mice. We found that the titers of systemic IgG resulted OVA-dosis dependent and slightly higher for 0.3 mg OVA than for 0.6 mg OVA. This means that a threshold dose exists above which a systemic response can not be improved. The presence of archaeolipids in the ternary matrix of UDa-OVA should be responsible for the earlier and pronounced response that requires lower amounts of OVA than the obtained with conventional (without archaeolipids) ultradeformable liposomes. It is likely therefore that in vivo the leishmanicidal effect of UDa could result from a synergistic effect fruit from its multiple leishmanicidal activity and its superior (in the absence of penetration enhancers and organic solvent is ten-folds as compared to conventional liposomes) capacity of penetration across the stratum corneum.