DC-SIGN receptor is expressed by cells from cutaneous leishmaniasis lesions and differentially binds to Leishmania (Viannia) braziliensis and L. (Leishmania) amazonensis promastigotes

BACKGROUND Dendritic cells (DCs) specific intercellular adhesion molecule (ICAM)-3-grabbing non integrin receptor (DC-SIGN) binds to subgenera Leishmania promastigotes mediating its interaction with DC and neutrophils, potentially influencing the infection outcome. OBJECTIVES In this work, we investigated whether DC-SIGN receptor is expressed in cells from cutaneous leishmaniasis (CL) lesions as well as the in vitro binding pattern of Leishmania (Viannia) braziliensis (Lb) and L. (L.) amazonensis (La) promastigotes. METHODS DC-SIGN receptor was labeled by immunohistochemistry in cryopreserved CL tissue fragments. In vitro binding assay with CFSE-labeled Lb or La promastigotes and RAJI-transfecting cells expressing DC-SIGN (DC-SIGNPOS) or mock-transfected (DC-SIGNNEG) were monitored by flow cytometry at 2 h, 24 h and 48 h in co-culture. RESULTS In CL lesion infiltrate, DC-SIGNPOS cells were present in the dermis and near the epidermis. Both Lb and La bind to DC-SIGNPOS cells, while binding to DC-SIGNNEG was low. La showed precocious and higher affinity to DC-SIGNhi population than to DC-SIGNlow, while Lb binding was similar in these populations. CONCLUSION Our results demonstrate that DC-SIGN receptor is present in L. braziliensis CL lesions and interact with Lb promastigotes. Moreover, the differences in the binding pattern to Lb and La suggest DC-SIGN can influence in a difference way the intake of the parasites at the first hours after Leishmania infection. These results raise the hypothesis that DC-SIGN receptor could participate in the immunopathogenesis of American tegumentary leishmaniasis accounting for the differences in the outcome of the Leishmania spp. infection.

Visceral leishmaniasis caused by Leishmania (Leishmania) amazonensis associated with Hodgkin's lymphoma

ABSTRACT Visceral leishmaniasis (VL) is mainly caused by Leishmania (Leishmania) donovani and Leishmania (L.) infantum; however, other Leishmania species have been associated with VL. We report a case of a patient simultaneously diagnosed with VL caused by Leishmania (L.) amazonensis and Hodgkin's lymphoma. After treatment with liposomal amphotericin B and chemotherapy, the patient presented a clinical cure. This case report reinforces the hypothesis that other Leishmania species can cause visceral lesions mainly related to immunosuppression.

Effect of phospholipase A2 inhibitors during infection caused by Leishmania (Leishmania) amazonensis

Background: Lipid metabolites play an important role in parasite differentiation and virulence. Studies have revealed that Leishmania sp. uses prostaglandins to evade innate barriers, thus enabling the parasites to survive inside immune cells. Despite the role of the enzyme Phospholipase A2 (PLA2) in prostaglandins production, few studies have investigated the role of parasite PLA2 during the interaction between L. (L.) amazonensis and the host (in vitro and in vivo) immune cells. Methods: In the present work, the leishmanicidal effect of PLA2 inhibitors, methyl arachidonyl fluorophosphonate (MAFP), bromoenol lactone (BEL) and aristolochic acid (AA) were investigated in vitro (promastigote and intracellular amastigote forms of L. (L.) amazonensis) and during in vivo infection using BALB/c mice. Results: The aforementioned inhibitors were deleterious to promastigote and amastigote forms of the L. (L.) amazonensis and were non-toxic to peritoneal macrophages from BALB/c mice. L. (L.) amazonensis-infected BALB/c mice treated with the inhibitor BEL presented decreased lesion size and skin parasitism; however, BEL treatment induced hepatotoxicity in BALB/c mice. Conclusions: Results presented herein suggested that PLA2 inhibitors altered L. (L.) amazonensis viability. In spite of liver toxicity, treatment with BEL was the most selective compound in vitro, as well in vivo, resulting in lower skin parasitism in the infected mice. These findings corroborate the role of PLA2 in parasite virulence and maintenance in vertebrate hosts, and suggest that molecules structurally related to BEL should be considered when planning compounds against Leishmania sp.

Effect of phospholipase A2 inhibitors during infection caused by Leishmania (Leishmania) amazonensis

Lipid metabolites play an important role in parasite differentiation and virulence. Studies have revealed that Leishmania sp. uses prostaglandins to evade innate barriers, thus enabling the parasites to survive inside immune cells. Despite the role of the enzyme Phospholipase A2 (PLA2) in prostaglandins production, few studies have investigated the role of parasite PLA2 during the interaction between L. (L.) amazonensis and the host (in vitro and in vivo) immune cells. Methods: In the present work, the leishmanicidal effect of PLA2 inhibitors, methyl arachidonyl fluorophosphonate (MAFP), bromoenol lactone (BEL) and aristolochic acid (AA) were investigated in vitro (promastigote and intracellular amastigote forms of L. (L.) amazonensis) and during in vivo infection using BALB/c mice. Results: The aforementioned inhibitors were deleterious to promastigote and amastigote forms of the L. (L.) amazonensis and were non-toxic to peritoneal macrophages from BALB/c mice. L. (L.) amazonensis-infected BALB/c mice treated with the inhibitor BEL presented decreased lesion size and skin parasitism; however, BEL treatment induced hepatotoxicity in BALB/c mice. Conclusions: Results presented herein suggested that PLA2 inhibitors altered L. (L.) amazonensis viability. In spite of liver toxicity, treatment with BEL was the most selective compound in vitro, as well in vivo, resulting in lower skin parasitism in the infected mice. These findings corroborate the role of PLA2 in parasite virulence and maintenance in vertebrate hosts, and suggest that molecules structurally related to BEL should be considered when planning compounds against Leishmania sp.(AU)

Antileishmanial activity of the essential oil from Tetradenia riparia obtained in different seasons

The herbaceous shrub Tetradenia riparia has been traditionally used to treat inflammatory and infectious diseases. Recently, a study showed that T. riparia essential oil (TrEO) obtained in summer has antileishmanial effects, although these results could be influenced by seasonal variation. This study evaluated the activity of the TrEO obtained in different seasons against Leishmania (Leishmania) amazonensis, in vitro and in vivo. The compounds in the TrEO were analysed by gas chromatography-mass spectrometry; terpenoids were present and oxygenated sesquiterpenes were the majority compounds (55.28%). The cytotoxicity and nitric oxide (NO) production were also tested after TrEO treatment. The TrEO from all seasons showed a 50% growth inhibitory concentration for promastigotes of about 15 ng/mL; at 30 ng/mL and 3 ng/mL, the TrEO reduced intracellular amastigote infection, independently of season. The TrEO from plants harvested in summer had the highest 50% cytotoxic concentration, 1,476 ng/mL for J774.A1 macrophages, and in spring (90.94 ng/mL) for murine macrophages. NO production did not change in samples of the TrEO from different seasons. The antileishmanial effect in vivo consisted of a reduction of the parasite load in the spleen. These results suggest that the TrEO has potential effects on L. (L.) amazonensis, consonant with its traditional use to treat parasitic diseases.

Natural infection of phlebotomines (Diptera: Psychodidae) by Leishmania (Leishmania) amazonensis in an area of ecotourism in Central-Western Brazil

Background Bonito municipality, known as an area of ecoturism, in Mato Grosso do Sul state, Brazil, is also a focus of visceral and cutaneous leishmaniases, with cases registered in both human and canine populations. This study sought to investigate natural infection by flagellate forms of Leishmania in phlebotomines of the urban area of Bonito.Findings Sand flies were collected fortnightly from October 2005 to July 2006 with modified automatic light traps installed in peridomiciles and animal shelters in the center and on the outskirts of the city. The females were dissected and their guts observed under an optical microscope. A total of 1977 specimens were captured, Lutzomyia longipalpis (88.4 %) and Bichromomyia flaviscutelata (3.0 %) being the most frequent species. Bi. flaviscutellata was found infected by flagellates that were identified as Leishmania (Leishmania) amazonensis by indirect immunofluorescence reaction, employing monoclonal antibodies and the biotin-avidin system. This is the first report of natural infection by L. amazonensis in Bi. flaviscutellata in a Brazilian urban area.Conclusions As Bi. flaviscutellata is only slightly attracted by humans, the transmission of L. amazonensis in the study area may have a zoonotic character; however, the sympatric occurrence of this parasite andLu. longipalpis should be taken into consideration by the local health authorities since this sand fly has already been found with L. amazonensis DNA in a focus of canine visceral leishmaniasis in Bonito municipality.

Leishmanicidal activities of the extract from Blepharocalyx salicifolius (Kunth) O. Berg, Myrtaceae / Atividade leishmanicida do extrato de Blepharocalyx salicifolius (Kunth) O. Berg, Myrtaceae

Crude ethanolic extracts from Blepharocalyx salicifolius (Kunth) O. Berg, Myrtaceae, was fractioned by Gel Permeation Chromatography, using SephadexTM LH-20 gel. Sixteen fractions were obtained and were supplied to cytotoxicity in vitro assay against Leishmania (L.) amazonensis amastigota cells. It was observed eight cytotoxic fractions against Leishmania (L.) amazonensis amastigota cells at range of 19 to 29 µg.mL-1. Two of them were not citotoxic against human peripheral blood mononuclear cell, with a great potential to isolation of more selective leishmanicidal substances.

O extrato etanólico bruto de Blepharocalyx salicifolius (Kunth) O. Berg, Myrtaceae, foi fracionado por meio de Cromatografia de Permeação em Gel, utilizando-se SephadexTM LH-20. Dezesseis frações foram obtidas e foram submetidas ao ensaio de citotoxicidade in vitro contra células amastigotas de Leishmania (Leishmania) amazonensis. Verificou-se atividade citocida contra células amastigotas de Leishmania (L.) amazonensis em oito frações, a uma concentração de 19 a 29 µg.mL-1. Duas destas frações apresentaram baixa toxicidade para células mononucleares de sangue periférico humano, com grande potencial de isolamento de substâncias leishmanicidas mais seletivas.

Domestic feline cutaneous leishmaniasis in the municipality of Ribas do Rio Pardo, Mato Grosso do Sul state, Brazil: a case report

Cutaneous leishmaniases are anthropozoonoses that involve many species of Leishmania and a wide variety of wild mammalian hosts, thus presenting high importance to public health. This study reports the second case of feline leishmaniasis in Mato Grosso do Sul state, in which Leishmania (Leishmania) amazonensis was found in a domestic cat from Ribas do Rio Pardo. Clinical signs were similar to those observed in other diseases commonly diagnosed in cats, such as cryptococcosis and sporotrichosis. Cutaneous leishmaniasis should, therefore, be added to differential diagnoses by feline veterinary practitioners, and also adequate investigations should be carried out to verify the relevance of domestic cats as L. amazonensis reservoirs.

Revisão sobre a patogenia da leishmaniose tegumentar americana na Amazônia, com ênfase à doença causada por Leishmania (V. ) braziliensis e Leishmania (L. ) amazonensis / Revisiting the pathogenesis of the american tegumentary leishmaniasis in Amazonian, with emphasis to the disease due to Leishmania (V. ) braziliensis and Leishmania (L.) amazonensis

A patogenia da leishmaniose tegumentar americana (LTA) na Amazônia foi revisada à luz dos mais recentes aspectos associados ao espectro clínico, histopatológico e imunopatológico da doença causada por Leishmania (V.) braziliensis e Leishmania (L.) amazonensis. Esta revisão mostrou a existência de uma dicotomia entre as duas espécies de Leishmania e a resposta imune celular; enquanto a L. (V.) braziliensis mostra forte tendência em dirigir a infecção, a partir da forma central do espectro clínico-imunológico, a leishmaniose cutânea localizada (LCL), para o pólo imunológico hiperreativo, representado pela leishmaniose cutâneo-mucosa (LCM), com exacerbação da hipersensibilidade e perfil da resposta CD4 tipo-Thl, a L. (L.) amazonensis mostra o oposto, dirige a infecção para o pólo imunológico hiporreativo, representado pela leishmaniose cutânea anérgica difusa (LCAD), com forte inibição da hipersensibilidade e perfil da resposta CD4 tipo- Th2. Entre a forma central LCL e as formas polares LCM e LCAD a infecção passa por uma fase intermediária, a leishmaniose cutânea disseminada borderline (LCDB), com inibição parcial da hipersensibilidade e peifil da resposta CD4 Thl + Th2. Estes são, provavelmente, os principais mecanismos imunológicos que modulam a patogenia da LTA causada por L. (V.) braziliensis e L. (L.) amazonensis.

The pathogenesis of American tegumentary leishmaniasis (ATL) was reviewed ifl the light of more recent features of clinical, histopathological and immunopathological spectrum of disease caused by Leishmania (V.) braziliensis and Leishmania (L.) amazonensis. This review has shown a dichotomy in the interaction between these two species of Leishmania with the human .cellular immune response; while L. (V.) braziliensis shows a clear tendency to direct infection, from the localized cutaneous leishmaniasis (LCL) in the center of the clinical-immunological spectrum of disease, to the hyperactive immunologic pole represented by mucocutaneous leishmaniasis (MCL), which shows exacerbated hypersensitivity reaction and CD4 Thl-type immune response, L. (L.) amazonensis shows the opposite,. directing infection to the hypoactive immunologic pole consisted by anergic diffuse cutaneous leishmaniasis (ADCL), associated with a marked inhibition of hypersensitivity reaction and CD4 Th2type immune response. Between the central LCL and thetwo polar MCL and ADCL forms the infection may present an intermediary phase, borderline disseminated cutaneous leishmaniasis (BDCL), which shows partial inhibition of hypersensitivity reaction and a mixed CD4 Thl plus Th2 immune response. These are probably the main immunological mechanisms regarding the immune response dichotomy that modulates the pathogenesis of ATL caused by these Leishmania parasites.

The activity of azithromycin against Leishmania (Viannia) braziliensis and Leishmania (Leishmania) amazonensis in the golden hamster model

New therapeutic alternatives against leishmaniasis remain a priority. The activity of azithromycin against Leishmania (Leishmania) major has been previously demonstrated. Different responses among species of Leishmania make species-specific drug screening necessary. The activity of azithromycin against Leishmania (Viannia) braziliensis and Leishmania (Leishmania) amazonensis was evaluated in golden hamsters infected through footpad injections of metacyclic promastigotes, and compared with untreated controls and animals treated with meglumine antimoniate. Footpad thickness, lesion cultures and dissemination sites were analyzed. Treatment of golden hamsters with oral azithromycin at 450mg/kg had no activity against infections with Leishmania (Leishmania) amazonensis. For infections due to Leishmania (Viannia) braziliensis, azithromycin demonstrated significant activity relative to untreated controls, but inferior to meglumine antimoniate, for controlling lesion size. Neither drug was able to totally eliminate parasites from the lesions. It was concluded that azithromycin has activity against Leishmania (Viannia) braziliensis but not against Leishmania (Leishmania) amazonensis in this model.

Novas alternativas terapêuticas contra a leishmaniose são ainda uma prioridade. A atividade da azitromicina contra a Leishmania (Leishmania) major foi anteriormente demonstrada. Diferentes respostas entre as espécies de Leishmania fazem com que um screening de drogas específicas para espécies seja necessário. A atividade da azitromicina contra a Leishmania (Viannia) braziliensis e a Leishmania (Leishmania) amazonensis foi avaliada em Golden hamsters infectados a través de injeções de promastigotas metacíclicas e comparando com controles sem tratamento e animais tratados com antimoniato de N-metil-glucamina. Foram analisadas a espessura da pata, a cultura das lesões e disseminação para órgãos internos. A azitromicina oral em dose de 450mg/kg não teve atividade contra a infecção por Leishmania ( Leishmania) amazonensis. Para infecções devidas à Leishmania (Viannia) braziliensis, a azitromicina teve uma atividade significativa em relação aos controles sem tratamento, mas foi inferior ao antimoniato de N-metil-glucamina quanto ao controle do tamanho das lesões. Nenhuma das drogas conseguiu eliminar totalmente os parasitos das lesões. Foi concluído que a azitromicina tem atividade contra Leishmania (Viannia) braziliensis, mas não tem atividade contra Leishmania (Leishmania) amazonensis neste modelo.