FVB/NJ strain as a mouse model for cutaneous leishmaniasis by Leishmania (L.) amazonensis

BACKGROUND Leishmaniases encompass a spectrum of neglected diseases caused by parasites of the genus Leishmania, grouped in two forms: tegumentary and visceral leishmaniasis. OBJECTIVES In this study, we propose Friend Virus B NIH Jackson (FVB/NJ) mouse strain as a new experimental model of infection with Leishmania (Leishmania) amazonensis, the second most prevalent agent of tegumentary leishmaniasis in Brazil. METHODS AND FINDINGS We performed in vitro infections of FVB/NJ macrophages and compared them with BALB/c macrophages, showing that BALB/c cells have higher infection percentages and a higher number of amastigotes/cell. Phagocytosis assays indicated that BALB/c and FVB/NJ macrophages have similar capacity to uptake parasites after 5 min incubations. We also investigated promastigotes' resistance to sera from FVB/NJ and BALB/c and observed no difference between the two sera, even though FVB/NJ has a deficiency in complement components. Finally, we subcutaneously infected FVB/NJ and BALB/c mice with 2 × 106 parasites expressing luciferase. Analysis of lesion development for 12 weeks showed that FVB/NJ and BALB/c mice have similar lesion profiles and parasite burdens. MAIN CONCLUSIONS This work characterises for the first time the FVB/NJ mouse as a new model for tegumentary leishmaniasis caused by Leishmania (L.) amazonensis.

Evaluation of different total Leishmania amazonensis antigens for the development of a first-generation vaccine formulated with a Toll-like receptor-3 agonist to prevent cutaneous leishmaniasis

BACKGROUND Unfortunately, no any vaccine against leishmaniasis has been developed for human use. Therefore, a vaccine based on total Leishmania antigens could be a good and economic approach; and there are different methodologies to obtain these antigens. However, it is unknown whether the method to obtain the antigens affects the integrity and immune response caused by them. OBJECTIVES to compare the protein profile and immune response generated by total L. amazonensis antigens (TLA) produced by different methods, as well as to analyse the immune response and protection by a first-generation vaccine formulated with sonicated TLA (sTLA) and polyinosinic:polycytidylic acid [Poly (I:C)]. METHODS TLA were obtained by four different methodologies and their integrity and immune response were evaluated. Finally, sTLA was formulated with Poly (I:C) and their protective immune response was measured. FINDINGS sTLA presented a conserved protein profile and induced a strong immune response. In addition, Poly (I:C) improved the immune response generated by sTLA. Finally, sTLA + Poly (I:C) formulation provided partial protection against L. amazonensis infection. MAIN CONCLUSIONS The protein profile and immune response depend on the methodology used to obtain the antigens. Also, the formulation sTLA + Poly (I:C) provides partial protection against cutaneous leishmaniasis in mice.

Importância da resolvinas na infecção por Leishmania Amazonensis / Importance of resolvins in Leishmania Amazonensis infection

A Leishmaniose Cutânea Difusa (LCD) é uma manifestação clínica. rara causada pela Leishmania amazonensis que é caracterizada por uma resposta celular. parasitária ineficiente e macrófagos intensamente parasitados nas lesões cutâneas.. Mediadores lipídicos e seus precursores desempenham um papel crucial durante a. infecção por Leishmania. Estudos prévios demonstram que pacientes com leishmaniose. tegumentar, exibem um distinto balanço de eicosanoides in situ e sistêmico.. Recentemente, demonstrou-se que mediadores lipídicos especializados na pró-resolução. desempenham um papel crítico na redução de processos inflamatórios patológicos. induzindo a restauração da homeostasia em diferentes modelos experimentais. Entre. esses mediadores, as resolvinas da série D exibem potente atividade anti-inflamatória e. imuno-regulatória que inclui a inibição da quimiotaxia leucocitária e bloqueio na. produção de citocinas pró-inflamatórias. No entanto, ainda é desconhecido se as. resolvinas desempenham um papel significativo no estabelecimento e persistência da. infecção por Leishmania. OBJETIVO: Nesse estudo, avaliamos os níveis circulantes. de Resolvina D1 (RvD1) em pacientes com leishmaniose tegumentar apresentando a. forma clínica cutânea localizada (LCL) ou difusa. RESULTADOS: Nossos resultados. demonstram que pacientes com LCD apresentam maiores níveis plasmáticos de RvD1. quando comparados a LCL ou controles endêmicos. Além disso, os níveis séricos de. RvD1 em pacientes com LCD se correlacionam positivamente com a Arginase I e TGF-. β, enquanto que inversamente com os níveis sistêmicos de TNF-α. Experimentos. adicionais in vitro utilizando macrófagos humanos revelaram que a RvD1 promove a. replicação intracelular da L. amazonensis por um mecanismo associado a indução da. enzima heme oxigenase-1. CONCLUSÃO: Os resultados sugerem que a via de. produção da RvD1 pode servir como uma potencial estratégia terapêutica para os. pacientes com LCD.

INTRODUCTION: Diffuse Cutaneous Leishmaniasis (DCL) is a rare clinical manifestation caused by Leishmania amazonensis that is characterized by an inefficient parasite-specific cellular responses and heavily parasitized macrophages in skin lesions. Lipid mediators and their precursors play a crucial role during Leishmania infection. Previous works have shown that patients with cutaneous leishmaniasis exhibit a distinct in situ and systemic balance of this eicosanoids. Recently, pro-resolution lipid mediators have been shown to play critical role in dampening pathological inflammatory processes to reestablish homeostasis in a diverse range of experimental settings. Among these mediators, resolvins from D series have been described to exhibit potent antiinflammatory and immune-regulatory activities that include inhibition of leukocyte chemotaxis and blockage on the production of proinflammatory cytokines. However, whether resolvins play significant roles in establishment and persistence of Leishmania infection is currently unknown. AIM: We addressed this question by assessing circulating levels of resolvin D1 (RvD1) in tegumentary leishmaniasis patients presenting localized cutaneous leishmaniasis (LCL) or diffuse disease. RESULTS: We found that DCL patients have higher plasma levels of RvD1 when compared with LCL patients or endemic controls. In addition, the levels of this mediator were positively correlated with arginase-I and TGF-β and were negatively correlated with TNF-α levels. Additional in vitro experiments using primary human macrophages revealed that resolvin D1 promotes the intracellular L. amazonensis replication for a mechanism dependent on induction of heme oxygenase-1 enzyme. CONCLUSION: These results indicate that targeting RvD1 could serve as potential strategy for DCL patients.

Estudios de susceptibilidad de cepas de Leishmania aethiopica frente a alcaloides de Galipea longiflora (Evanta) / Susceptibility studies on Leishmania aethiopica strains against total alkaloids from Galipea longiflora (Evanta)

El Instituto de Investigaciones Fármaco Bioquímicas (IIFB), de la Facultad de Ciencias Farmacéuticas y Bioquímicas, de la UMSA, desarrolla trabajos sobre la actividad leishmanicida, de los alcaloides totales (CAT) obtenidos de la corteza de la especie medicinal amazónica conocida como Evanta (Galipea longiflora) por los Pueblos Tacana, Tsimane y Mosetene. Como parte de las actividades del Proyecto UMSA-ASDI Biomoleculas de interés medicinal e industrial (antiparasitarios) hemos podido contar con la estadía, en el IIFB, de un investigador del Armauer Hansen Research Institute (AHRI) de Etiopia, lo que nos ha permitido desarrollar evaluaciones de CAT, Miltefocine y Amfotericina B, frente a cepas de Leishmania aethiopica, agente causante de las diversa formas de Leishmaniais cutánea en Etiopía. Un total de seis cepas, de L. aethiopica, fueron adaptadas a condiciones in vitro y mostraron un comportamiento homogéneo frente a CAT, cinco de estas cepas mostraron un valor promedio de IC50 = 8,68 ±1,56 mg/mL, valor algo inferior a los calculados para nuestras cepas de referencia, L. amazonensis y L. braziliensis con IC50 = 11,73 ± 4,32 mg/mL y IC50 = 12,28 ±- 2,95 mg/mL, respectivamente. Excepto por una cepa de L. aethiopica que mostro valores consistentemente más elevados que el resto con IC50= 14,37 ± 3,58 mg/mL. Como consecuencia de esta interacción científica, la Universidad Mayor de San Andrés (UMSA) ha firmado un Memorandum de Entendimiento para el desarrollo de investigaciones conjuntas, con el Armauer Hansen Research Institute (AHRI), dependiente del Ministerio de Salud de Etiopia y explorar la posibilidad de que nuestra experiencia de validación clínica con Evanta en el tratamiento de leishmaiasis cutánea, en Bolivia, podría ser replicada en Etiopía, donde se reportan entre 20,000 a 30,000 nuevos casos de Leismaniasis por año.

The Instituto de Investigaciones Fármaco Bioquímicas (IIFB), at the Faculty of Pharmaceutical and Biochemical Sciences, from UMSA, carry out work related to the leishmanicidal activity of the total alkaloids (CAT) obtained from the bark of the Amazonian medicinal species known as Evanta (Galipea longiflora) by the Tacana, Tsimane y Mosetene people. As part of the activities develop by the UMSA-ASDI Project Biomolecules of medicinal and industrial Interest (antiparasitic) we had a visit, in our laboratories at IIFB, of a researcher from The Armauer Hansen Research Institute (AHRI) from Ethiopia, during his stay we were able to carry out evaluations of CAT, Miltefocine and Anphotericin B, against strains of L. aethiopica, causative agent of the different manifestations of cutaneous leishmaniasis in Ethiopia. A total of six strains of L. aethiopica, were adapted to in vitro a conditions, at IIFB; and did show homogenous behavior against CAT. Five of the strains, showed an average calculated value for IC50 = 8.68 ±1.56 mg/mL, a value somewhat lower to the calculated for the reference strains L. amazonensis and L. braziliensis with IC50 = 11.73 ± 4.32 mg/mL and IC50 = 12.28 +/- 2.95 mg/mL, respectively. Except for one strain that showed values somewhat higher, to the other strains, consistently through our studies, with IC50 = 14.37 ± 3.58 mg/mL. As a consequence of our scientific interaction, the Universidad Mayor de San Andrés (UMSA) has signed a Memorandum of Understanding for the development of joint research with the Armauer Hansen Research Institute (AHRI) that belongs to the Ministry of Health in Ethiopia, and explore the possibilities to replicate the Bolivian clinical validation experience of Evanta in the treatment of cutaneous leishmaniasis, in Ethiopia where the annual incidence is estimated to be between 20, 000 to 30, 0000.

Peripheral blood fibrocytes: new information to explain the dynamics of Leishmania infection

Fibrocytes are important for understanding the progression of many diseases because they are present in areas where pathogenic lesions are generated. However, the morphology of fibrocytes and their interactions with parasites are poorly understood. In this study, we examined the morphology of peripheral blood fibrocytes and their interactions with Leishmania (L.) amazonensis . Through ultrastructural analysis, we describe the details of fibrocyte morphology and how fibrocytes rapidly internalise Leishmania promastigotes. The parasites differentiated into amastigotes after 2 h in phagolysosomes and the infection was completely resolved after 72 h. Early in the infection, we found increased nitric oxide production and large lysosomes with electron-dense material. These factors may regulate the proliferation and death of the parasites. Because fibrocytes are present at the infection site and are directly involved in developing cutaneous leishmaniasis, they are targets for effective, non-toxic cell-based therapies that control and treat leishmaniasis.

Low and high-dose intradermal infection with Leishmania majorand Leishmania amazonensis in C57BL/6 mice

A model of skin infection with Leishmania amazonensiswith low doses of parasites is compared to infection with high doses of L. amazonensis and low and high doses of Leishmania major. C57BL/6 mice were infected with 10³ or 10(6) parasites in the ear and the outcome of infection was assessed. The appearance of lesions in mice infected with 10³ parasites was delayed compared to mice infected with 10(6) Leishmania and parasites were detectable at the infection site before lesions became apparent. Mice infected with L. amazonensisdisplayed persistent lesions, whereas infection with L. major spontaneously healed in all groups, although lymphocytes persisted at the site of infection after healing. Macrophages persisted only in L. amazonensis-infected mice. High-dose L. amazonensis-infected mice produced lower levels of IFN-γ and TNF than mice infected with L. major. No correlation between the persistence of parasites and IL-10 levels and the production of nitric oxide or urea by macrophages was found. We conclude that infection with low doses of L. amazonensisin the dermis changes the course of infection by delaying the appearance of lesions. However, low-dose infection does not change the outcomes of susceptibility and cytokine production described for subcutaneous infection with high numbers of parasites.

Espécies novas de Leuropeltis Hebard, 1921 (Blattellidae, Pseudophyllodromiinae) do estado do Amazonas, Brasil / New species of Leuropeltis Hebard, 1921 (Blattellidae, Pseudophyllodromiinae) from Amazonas State, Brazil

Duas espécies novas de Leuropeltis são descritas e ilustradas com base nos espécimens machos. Caracteres morfológicos e genitália são detalhaddos. O gênero é registrado pela primeira vez no Brasil, no Estado do Amazonas.

Two new species of Leuropeltis are described and illustrated based on male specimens. External morphology and genitalia are detailed. The genus is registered for the first time from the Brazil, Amazonas State.

DNA sequencing confirms the involvement of Leishmania (L.) amazonensis in american tegumentary leishmaniasis in the state of São Paulo, Brazil

INTRODUCTION: American tegumentary leishmaniasis (ATL) represents one of the most important public health issues in the world. An increased number of autochthonous cases of ATL in the Northeastern region of São Paulo State has been documented in the last few years, leading to a desire to determine the Leishmania species implicated. METHODS: PCR followed by DNA sequencing was carried out to identify a 120bp fragment from the universal kDNA minicircle of the genus Leishmania in 61 skin or mucosal biopsies from patients with ATL. RESULTS: DNA sequencing permitted the identification of a particular 15bp fragment (5' …GTC TTT GGG GCA AGT... 3') in all samples. Analysis by the neighbor-joining method showed the occurrence of two distinct groups related to the genus Viannia (V) and Leishmania (L), each with two subgroups. Autochthonous cases with identity to a special Leishmania sequence not referenced in Genbank predominated in subgroup V.1, suggesting the possible existence of a subtype or mutation of Leishmania Viannia in this region. In the subgroup L.2, which showed identity with a known sequence of L. (L.) amazonensis, there was a balanced distribution of autochthonous and non-autochthonous cases, including the mucosal and mucocutaneus forms in four patients. The last observation may direct us to new concepts, since the mucosal compromising has commonly been attributed to L. (V.) braziliensis, even though L. (L.) amazonensis is more frequent in the Amazonian region. CONCLUSIONS: These results confirm the pattern of distribution and possible mutations of these species, as well as the change in the clinical form presentation of ATL in the São Paulo State.