ABSTRACTDisfiguring skin lesions caused by several species of theLeishmaniaparasite characterize cutaneous leishmaniasis (CL). Successful treatment of CL with intravenous (i.v.) liposomal amphotericin B (LAmB) relies on the presence of adequate antibiotic concentrations at the dermal site of infection within the inflamed skin. Here, we have investigated the impact of the local skin inflammation on the pharmacokinetics (PK) and efficacy of LAmB in two murine models of localized CL (Leishmania majorandLeishmania mexicana) at three different stages of disease (papule, initial nodule, and established nodule). Twenty-four hours after the administration of one 25 mg/kg of body weight LAmB (i.v.) dose to infected BALB/c mice (n= 5), drug accumulation in the skin was found to be dependent on the causative parasite species (L. major>L. mexicana) and the disease stage (papule > initial nodule > established nodule > healthy skin). Elevated tissue drug levels were associated with increased vascular permeability (Evans blue assay) and macrophage infiltration (histomorphometry) in the infected skin, two pathophysiological parameters linked to tissue inflammation. After identical treatment of CL in the two models with 5 × 25 mg/kg LAmB (i.v.), intralesional drug concentrations and reductions in lesion size and parasite load (quantitative PCR [qPCR]) were all ≥2-fold higher forL. majorthan forL. mexicana. In conclusion, drug penetration of LAmB into CL skin lesions could depend on the disease stage and the causativeLeishmaniaspecies due to the influence of local tissue inflammation.
Failure of Liposomal-amphotericin B Treatment for New World Cutaneous Leishmaniasis due to Leishmania braziliensis
