Ursolic Acid Potentializes Conventional Therapy in Experimental Leishmaniasis.

Ursolic acid (UA) is a triterpene with a broad array of pharmacological activities. In leishmaniasis, UA killed different species of parasites, and it was active in the experimental model of cutaneous and visceral leishmaniasis. Thus, the objective of this work was to study the therapeutic efficacy of the conventional drugs amphotericin B (AmB) or glucantime (Glu) combined with UA in experimental visceral and cutaneous leishmaniasis, respectively. L. (L.) infantum-infected hamsters were treated with AmB alone or combined with UA. L. (L.) amazonensis-infected BALB/c mice were treated with Glu alone or combined with UA. Animals were treated for 15 consecutive days by intraperitoneal or intralesional routes. Following one week after the last dose, the tissue parasitism and cellular immune responses were analyzed. Hamsters treated with 0.2 and 1.0 mg/kg of AmB plus 1.0 mg/kg of UA showed low hepatic and splenic parasitisms; however, AmB given as monotherapy did not reduce the number of viable parasites in the spleen of treated animals. In cutaneous leishmaniasis, Glu given as monotherapy was inactive at 2.0 mg/kg, showed mild activity at 10.0 mg/kg, and at 50.0 mg/kg was highly active at eliminating parasites in the skin. When animals were treated with Glu plus UA, higher leishmanicidal activity was observed in comparison to all groups treated with monotherapy schemes, and such activity was related to lesion improvement and upregulation of IFN-γ production. Altogether, data suggest that the association of drugs for the treatment of leishmaniasis can increase the efficiency of the treatment and decrease the toxicity associated to the conventional drugs.

Topical buparvaquone nano-enabled hydrogels for cutaneous leishmaniasis.

Leishmaniasis is a neglected disease presenting cutaneous, mucosal and visceral forms and affecting an estimated 12 million mostly low-income people. Treatment of cutaneous leishmaniasis (CL) is recommended to expedite healing, reduce risk of scarring, prevent parasite dissemination to other mucocutaneous (common with New World species) or visceral forms and reduce the chance of relapse, but remains an unmet need. Available treatments are painful, prolonged (>20 days) and require hospitalisation, which increases the cost of therapy. Here we present the development of optimised topical self-nanoemulsifying drug delivery systems (SNEDDS) loaded with buparvaquone (BPQ, a hydroxynapthoquinone from the open Malaria Box) for the treatment of CL from New World species. The administration of topical BPQ-SNEDDS gels for 7 days resulted in a reduction of parasite load of 99.989 ± 0.019% similar to the decrease achieved with intralesionally administered Glucantime® (99.873 ± 0.204%) in a L. amazonensis BALB/c model. In vivo efficacy was supported by ex vivo permeability and in vivo tape stripping studies. BPQ-SNEDDS and their hydrogels demonstrated linear flux across non-infected CD-1 mouse skin ex vivo of 182.4 ± 63.0 µg cm-2 h-1 and 57.6 ± 10.8 µg cm-2 h-1 respectively localising BPQ within the skin in clinically effective concentrations (227.0 ± 45.9 µg and 103.8 ± 33.8 µg) respectively. These levels are therapeutic as BPQ-SNEDDS and their gels showed nanomolar in vitro efficacy against L. amazonensis and L. braziliensis amastigotes with excellent selectivity index toward parasites versus murine macrophages. In vivo tape stripping experiments indicated localisation of BPQ within the stratum corneum and dermis. Histology studies confirmed the reduction of parasitism and indicated healing in animals treated with BPQ-SNEDDS hydrogels. These results highlight the potential clinical capability of nano-enabled BPQ hydrogels towards a non-invasive treatment for CL.

Clinical and Immunological Features of Human Leishmania (L.) infantum-Infection, Novel Insights Honduras, Central America.

Leishmania (Leishmania) infantum is the etiological agent of both American visceral leishmaniasis (AVL) and non-ulcerated cutaneous leishmaniasis (NUCL) in Honduras. Although AVL is the most severe clinical form of infection, recent studies have shown that human immune response to parasite infection can result in a clinical-immunological spectrum. The overall prevalence rate of infection and clinical-immunological profiles of the L. (L.) infantum infection in Amapala municipality, South Honduras was determined. We examined 576 individuals with diagnosis based on combined ELISA (IgG/IgM) and DTH assays. We also used genus-specific kDNA PCR and Hsp70 PCR-RFLP for NUCL cases. Clinical evaluation found 82% asymptomatic and 18% symptomatic individuals. All symptomatic cases (n = 104) showing NUCL were positive for parasites. We identified L. (L.) infantum species in 100% of the skin lesion scrapings and in 90% of the blood samples from NUCL cases studied. A total of 320 asymptomatic individuals were exposed (ELISA+ and/or DTH+), providing an overall L. (L.) infantum prevalence of 73.6%. Clinical, parasitological, and immunological evaluations suggest seven infection profiles, three asymptomatic and four symptomatic. This represents the first report on clinical and immunological features of human L. (L.) infantum-infection in Amapala municipality, Honduras.

Repurposing Butenafine as An Oral Nanomedicine for Visceral Leishmaniasis.

Leishmaniasis is a neglected tropical disease affecting more than 12 million people worldwide, which in its visceral clinical form (VL) is characterised by the accumulation of parasites in the liver and spleen, and can lead to death if not treated. Available treatments are not well tolerated due to severe adverse effects, need for parenteral administration and patient hospitalisation, and long duration of expensive treatments. These treatment realities justify the search for new effective drugs, repurposing existing licensed drugs towards safer and non-invasive cost-effective medicines for VL. In this work, we provide proof of concept studies of butenafine and butenafine self-nanoemulsifying drug delivery systems (B-SNEDDS) against Leishmania infantum. Liquid B-SNEDDS were optimised using design of experiments, and then were spray-dried onto porous colloidal silica carriers to produce solid-B-SNEDDS with enhanced flow properties and drug stability. Optimal liquid B-SNEDDS consisted of Butenafine:Capryol 90:Peceol:Labrasol (3:49.5:24.2:23.3 w/w), which were then sprayed-dried with Aerosil 200 with a final 1:2 (Aerosil:liquid B-SNEDDS w/w) ratio. Spray-dried particles exhibited near-maximal drug loading, while maintaining excellent powder flow properties (angle of repose <10°) and sustained release in acidic gastrointestinal media. Solid-B-SNEDDS demonstrated greater selectivity index against promastigotes and L. infantum-infected amastigotes than butenafine alone. Developed oral solid nanomedicines enable the non-invasive and safe administration of butenafine as a cost-effective and readily scalable repurposed medicine for VL.

Histopathological features of skin lesions in patients affected by non-ulcerated or atypical cutaneous leishmaniasis in Honduras, Central America.

In Honduras visceral leishmaniasis and non-ulcerated or atypical cutaneous leishmaniasis (NUCL) are caused by the species Leishmania (L.) infantum chagasi. NUCL is the most common clinical form in the southern regions of the country, mainly affecting the young. In view of the lack of knowledge about the pathogenesis of the disease pattern caused by L. (L) infantum chagasi in individuals affected by NUCL, the aim of the present study was to describe in detail the histopathological features of the skin lesion caused by the parasite. Biopsies from human NUCL lesions with a positive parasitological diagnosis were collected and processed using standard histological techniques. Paraffin sections stained by haematoxylin and eosin were used to examine the histopathological alterations seen in the skin. The lesions varied between 3 and 5 mm, and the majority of the patients (60%) had a single lesion. Lesions were more frequently seen in females (65%), with an average age of 33.4 years. Microscopically, the skin lesions were characterized by mononuclear inflammatory infiltrate in the dermis composed of lymphocytes, macrophages and a few plasma cells. The intensity of the infiltration varied from discrete to intense. In both cases, the parasitic infection was discrete. Granulomas were present in 60% of cases and were associated with intense inflammation. The data revealed by the histopathological alterations in the skin of individuals affected by NUCL suggest activation of a cellular immune response that potentially controls parasite spreading.

Evaluation of Rhamnetin as an Inhibitor of the Pharmacological Effect of Secretory Phospholipase A2.

Rhamnetin (Rhm), 3-O-methylquercetin (3MQ), and Rhamnazin (Rhz) are methylated derivatives of quercetin commonly found in fruits and vegetables that possess antioxidant and anti-inflammatory properties. Phospholipase A2 (PLA2) displays several important roles during acute inflammation; therefore, this study aimed at investigating new compounds able to inhibit this enzyme, besides evaluating creatine kinase (CK) levels and citotoxicity. Methylated quercetins were compared with quercetin (Q) and were incubated with secretory PLA2 (sPLA2) from Bothrops jararacussu to determine their inhibitory activity. Cytotoxic studies were performed by using the J774 cell lineage incubated with quercertins. In vivo tests were performed with Swiss female mice to evaluate decreasing paw edema potential and compounds' CK levels. Structural modifications on sPLA2 were made with circular dichroism (CD). Despite Q and Rhz showing greater enzymatic inhibitory potential, high CK was observed. Rhm exhibited sPLA2 inhibitory potential, no toxicity and, remarkably, it decreased CK levels. The presence of 3OH on the C-ring of Rhm may contribute to both its anti-inflammatory and enzymatic inhibition of sPLA2, and the methylation of ring A may provide the increase in cell viability and low CK level induced by sPLA2. These results showed that Rhm can be a candidate as a natural compound for the development of new anti-inflammatory drugs.

Modulation of inflammation response to murine cutaneous Leishmaniasis by homeopathic medicines: Antimonium crudum 30cH.

BACKGROUND: Leishmaniasis is a zoonotic disease caused by protozoan parasites of the mononuclear phagocytic system. The modulation activity of these cells can interfere in the host/parasite relationship and influences the prognosis. METHODS: We evaluated the effects of the homeopathic preparation Antimonium crudum 30cH on experimental infection induced by Leishmania (L.) amazonensis. Male Balb/c mice were inoculated with 2 × 10(6)Leishmania (L.) amazonensis promastigotes into the footpad and, after 48 h (acute phase) or 60 days (chronic phase), cell population of lymphocytes and phagocytes present in the peritoneal washing fluid and spleen were analyzed by flow cytometry and histopathology, with histometry of the subcutaneous primary lesion, local lymph node and spleen. Immunohistochemistry was performed to quantify CD3 (T lymphocyte), CD45RA (B lymphocyte) and CD11b (phagocytes) positive cells. RESULTS: In treated mice, during the acute phase, there was significant increase of the macroscopic lesion, associated to inflammatory edema, as well increase in the number of free amastigotes and B lymphocytes inside the lesion. Increase of B lymphocytes (predominantly B-2 cells) was also seen in the local lymph node, spleen and peritoneum. In the chronic phase, the inflammatory process in the infection focus was reduced, with reduced phagocyte migration and peritoneal increase of B-1a cells (precursors of B-2 immunoglobulin producers cells) and T CD8+ cells. CONCLUSION: The treatment of mice with Antimonium crudum 30cH induced a predominantly B cell pattern of immune response in Leishmania (L.) amazonensis experimental infection, alongside the increase of free amastigote forms number in the infection site. The clinical significance of this study is discussed, further studies are suggested.