Antifungal efficacy and immunomodulatory effect of PLGA nanoparticle-encapsulated itraconazole in histoplasmosis in vivo model

Introduction: Histoplasma capsulatum is the etiological agent of histoplasmosis, the most common endemic pulmonary mycosis. Itraconazole (ITZ) is the choice for mild disease and a step-down therapy in severe and disseminated clinical presentations. Drug encapsulation into nanoparticles (NPs) is an alternative to improve drug solubility and bioavailability, reducing undesirable interactions and drug degradation and reaching the specific therapeutic target with lower doses. Objective: evaluate the antifungal and immunomodulatory effect of ITZ encapsulated into poly(lactic-co-glycolic acid) (PLGA) NPs, administrated orally and intraperitoneally in an in vivo histoplasmosis model. Results: After intranasal infection and treatment of animals with encapsulated ITZ by intraperitoneal and oral route, fungal burden control, biodistribution, immune response, and histopathology were evaluated. The results showed that the intraperitoneal administered and encapsulated ITZ has an effective antifungal effect, significantly reducing the Colony-Forming-Units (CFU) after the first doses and controlling the infection dissemination, with a higher concentration in the liver, spleen, and lung compared to the oral treatment. In addition, it produced a substantial immunomodulatory effect on pro- and anti-inflammatory cytokines and immune cell infiltrates confirmed by histopathology. Conclusions: Overall, results suggest a synergistic effect of the encapsulated drug and the immunomodulatory effect contributing to infection control, preventing their dissemination.