A pilot and open trial to evaluate topical Bacterial Cellulose bio-curatives in the treatment of cutaneous leishmaniasis caused by L. braziliensis.

The treatment of cutaneous leishmaniasis (CL) in Brazil using pentavalent antimony (Sbv) is associated with a high failure rate and long time to heal. Moreover, standard Sbv treatment cures only 50-60% of the cases. In this pilot clinical trial, we evaluated the topical use of bacterial cellulose (BC) bio-curatives + Sbv in the treatment of CL caused by L. braziliensis, in Bahia, Brazil. A total of 20 patients were randomized in two groups assigned to receive either parenteral Sbv alone or parenteral Sbv plus topically applied BC bio-curatives. CL patients treated with Sbv + topical BC bio-curatives had a significantly higher cure rate at 60 days post initiation of treatment compared to CL patients treated with Sbv alone (P=0.01). At day 90 post initiation of treatment, cure rate was similar in the two groups as was overall healing time. Adverse effects or local reactions to topical BC application were not observed. This pilot trial shows that the potential use of a combined therapy consisting of topical BC bio-curatives and parenteral Sbv in favoring healing of CL lesions caused by L. braziliensis, at an early time point.

DETC-based bacterial cellulose bio-curatives for topical treatment of cutaneous leishmaniasis.

The treatment of leishmaniasis still relies on drugs with potentially serious adverse effects. Herein, we tested a topical formulation of bacterial cellulose (BC) membranes containing Diethyldithiocarbamate (DETC), a superoxide dismutase 1 inhibitor. Leishmania-infected macrophages exposed to BC-DETC resulted in parasite killing, without pronounced toxic effects to host cells. This outcome was associated with lower SOD1 activity and higher production of superoxide and cytokine mediators. Topical application of BC-DETC significantly decreased lesion size, parasite load and the inflammatory response at the infection site, as well as the production of both IFN-γ and TNF. Combination of topical BC-DETC plus intraperitoneal Sbv also significantly reduced disease development and parasite load. The leishmanicidal effect of BC-DETC was extended to human macrophages infected with L. braziliensis, highlighting the feasibility of BC-DETC as a topical formulation for chemotherapy of cutaneous leishmaniasis caused by L. braziliensis.

Topical amphotericin B in ultradeformable liposomes: Formulation, skin penetration study, antifungal and antileishmanial activity in vitro.

Aiming to improve the topical delivery of AmB to treat cutaneous fungal infections and leishmaniasis, ultradeformable liposomes containing amphotericin B (AmB-UDL) were prepared, and structural and functional characterized. The effect of different edge activators, phospholipid and AmB concentration, and phospholipid to edge activator ratio on liposomal deformability, as well as on AmB liposomal content, was tested. Liposomes having Tween 80 as edge activator resulted of maximal deformability and AmB/phospholipid ratio. These consisted of AmB-UDL of 107±8nm diameter, 0.078-polydispersity index and -3±0.2mV Z potential, exhibiting monomeric AmB encapsulated in the bilayer at a 75% encapsulation efficiency. After its cytotoxicity on keratinocytes (HaCaT cells) and macrophages (J774 cells) was determined, the in vitro antifungal activity of AmB-UDL was assayed. It was found that fungal strains (albicans and non-albicans Candida ATCC strains and clinical isolates of C. albicans) were more sensitive to AmB-UDL than mammal cells. Minimum inhibitory concentration values for AmB-UDL were 5-24 and 24-50 times lower than IC50 for J774 and HaCaT cells, respectively. AmB-UDL at 1.25µg/ml also displayed 100 and 75% anti- Leishmania braziliensis promastigote and amastigote activity, respectively. Finally, upon 1h of non-occlusive incubation, the total accumulation of AmB in human skin was 40 times higher when applied as AmB-UDL than as AmBisome. AmB-UDL provided a profound AmB penetration toward deep epithelial layers, achieved without classical permeation enhancers. Because of that, topical treatments of cutaneous fungal infection and leishmaniasis with AmB-UDL may be regarded of potential of clinical significance.

Preparation and characterization of a bacterial cellulose/silk fibroin sponge scaffold for tissue regeneration.

Bacterial cellulose (BC) and silk fibroin (SF) are natural biopolymers successfully applied in tissue engineering and biomedical fields. In this work nanocomposites based on BC and SF were prepared and characterized by scanning electron microscopy (SEM), infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). In addition, the investigation of cytocompatibility was done by MTT, XTT and Trypan Blue dye technique. Cellular adhesion and proliferation were detected additionally. The evaluation of genotoxicity was realized by micronucleus assay. In vitro tests showed that the material is non-cytotoxic or genotoxic. SEM images revealed a greater number of cells attached at the BC/SF:50% scaffold surface than the pure BC one, suggesting that the presence of fibroin improved cell attachment. This could be related to the SF amino acid sequence that acts as cell receptors facilitating cell adhesion and growth. Consequently, BC/SF:50% scaffolds configured an excellent option in bioengineering depicting its potential for tissue regeneration and cultivation of cells on nanocomposites.