Zymosan enhances in vitro phagocyte function and the immune response of mice infected with Paracoccidioides brasiliensis

Paracoccidioides brasiliensis is the major etiologic agent of Paracoccidioidomycosis (PCM), the most frequent human deep mycosis in Latin America. It is proposed that masking of β-glucan in P. brasiliensis cell wall is a critical virulence factor that contributes to the development of a chronic disease characterized by a long period of treatment, which is usually toxic. In this context, the search for immunomodulatory agents for therapeutic purposes is highly desirable. One strategy is to use pattern recognition receptors (PRRs) ligands to stimulate the immune response mediated by phagocytes. Here, we sought to evaluate if Zymosan, a β-glucan-containing ligand of the PRRs Dectin-1/TLR-2, would enhance phagocyte function and the immune response of mice challenged with P. brasiliensis. Dendritic cells (DCs) infected with P. brasiliensis and treated with Zymosan showed improved secretion of several proinflammatory cytokines and expression of maturation markers. In addition, when cocultured with splenic lymphocytes, these cells induced the production of a potential protective type 1 and 17 cytokine patterns. In macrophages, Zymosan ensued a significant fungicidal activity associated with nitric oxide production and phagolysosome acidification. Importantly, we observed a protective effect of Zymosan-primed DCs delivered intranasally in experimental pulmonary PCM. Overall, our findings support the potential use of β-glucan-containing compounds such as Zymosan as an alternative or complementary antifungal therapy.

LAY SUMMARY

We report for the first time that Paracoccidioides brasiliensis-infected phagocytes treated with Zymosan (cell wall extract from bakers' yeast) show enhanced cytokine production, maturation, and fungal killing. Also, Zymosan-primed phagocytes induce a protective immune response in infected mice.

Activity and in vivo tracking of Amphotericin B loaded PLGA nanoparticles

The development of biocompatible polymeric nanoparticles has become an important strategy for optimizing the therapeutic efficacy of many classical drugs, as it may expand their activities, reduce their toxicity, increase their bioactivity and improve biodistribution. In this study, nanoparticles of Amphotericin B entrapped within poly (lactic-co-glycolic) acid and incorporated with dimercaptosuccinic acid (NANO-D-AMB) as a target molecule were evaluated for their physic-chemical characteristics, pharmacokinetics, biocompatibility and antifungal activity. We found high plasma concentrations of Amphotericin B upon treatment with NANO-D-AMB and a high uptake of nanoparticles in the lungs, liver and spleen. NANO-D-AMB exhibited antifungal efficacy against Paracoccidioides brasiliensis and induced much lower cytotoxicity levels compared to D-AMB formulation in vivo and in vitro. Together, these results confirm that NANO-D-AMB improves Amphotericin B delivery and suggest this delivery system as a potential alternative to the use of Amphotericin B sodium deoxycholate.

Effects of bromopride on expression of metalloproteinases and interleukins in left colonic anastomoses: an experimental study

Anastomotic dehiscence is the most severe complication of colorectal surgery. Metalloproteinases (MMPs) and interleukins (ILs) can be used to analyze the healing process of anastomosis. To evaluate the effects of bromopride on MMP and cytokine gene expression in left colonic anastomoses in rats with or without induced abdominal sepsis, 80 rats were divided into two groups for euthanasia on the third or seventh postoperative day (POD). They were then divided into subgroups of 20 rats for sepsis induction or not, and then into subgroups of 10 rats for administration of bromopride or saline. Left colonic anastomosis was performed and abdominal sepsis was induced by cecal ligation and puncture. A colonic segment containing the anastomosis was removed for analysis of gene expression of MMP-1α, MMP-8, MMP-13, IL-β, IL-6, IL-10, tumor necrosis factor-α (TNF-α), and interferon-γ (IFN-γ). On the third POD, bromopride was associated with increased MMP-1α, MMP-13, IL-6, IFN-γ, and IL-10 gene expression. On the seventh POD, all MMP transcripts became negatively modulated and all IL transcripts became positively modulated. In the presence of sepsis, bromopride administration increased MMP-8 and IFN-γ gene expression and decreased MMP-1, TNF-α, IL-6, and IL-10 gene expression on the third POD. On the seventh POD, we observed increased expression of MMP-13 and all cytokines, except for TNF-α. In conclusion, bromopride interferes with MMP and IL gene expression during anastomotic healing. Further studies are needed to correlate these changes with the healing process.