Perfil de citocinas do padrão Th1, Th2, Th17 e o estado redox de indivíduos com leishmaniose visceral pré e pós tratamento

A leishmaniose visceral (LV) é causada pelos protozoários intracelulares obrigatórios pertencentes ao complexo Leishamania donovani (L.donovani). O sucesso na cura da LV depende principalmente do estado imunitário do hospedeiro em combinação com os efeitos das drogas leishmanicidas. Nesse sentido, a resistência do hospedeiro a leishmaniose está associada à produção de citocinas envolvidas na indução e efetuação de uma resposta do tipo Th1, como IL-12, IFN-γ e TNF-α. Essa resposta culmina na ativação de macrófagos com conseqüente aumento na produção de metabólitos do estresse oxidativo com atividade leishmanicida. Por outro lado, a suscetibilidade à infecção e a progressão da doença estão relacionadas com o direcionamento de uma resposta do tipo Th2, com produção de IL-4 e de outras citocinas como a IL-10, que desativam macrófagos. A subpopulação de células Th17 vem ganhando importância na resposta contra a Leishmania, entretanto não se sabe até o momento se está envolvida na resistência ou suscetibilidade à infecção. Apesar desses resultados, são raros os trabalhos que tenham objetivado avaliar de forma sistemática, os perfis de resposta de células CD4+ em pacientes com LV, antes e após o tratamento. Desta forma, um dos objetivos do presente estudo foi quantificar as citocinas do perfil Th1, Th2 e Th17 nestas duas fases da evolução da doença. Outro objetivo foi avaliar o estado redox desses pacientes, uma vez que ao tentar eliminar o parasita através do processo de ativação de macrófagos, os mesmos podem liberar quantidades exageradas de metabólitos leishmanicidas, que podem levar a um estresse oxidativo envolvido na patogênese da doença. Foi observada uma tendência dos pacientes apresentarem um aumento nos níveis das citocinas pró-inflamatórias IL-17 e IFN-  antes do tratamento com diminuição após o tratamento. Diferenças significantes, foram detectadas em relação aos níveis de IL-6 e IL-10. Pacientes antes do tratamento apresentaram uma produção mais alta das duas citocinas em relação aos indivíduos controles. No entanto, após o tratamento, essa produção abaixou de forma significante, atingindo novamente níveis semelhantes aos dos indivíduos controles. Em relação ao estado redox detectamos que pacientes com a doença ativa apresentaram um aumento da substância malondialdeído (MDA), um indicador de peroxidação lipídica, associado a uma diminuição de carotenóides antioxidantes como o licopeno e a luteína o que revela a presença de um desequilíbrio oxidativo nesses pacientes. As associações entre os achados imunológicos e os relativos ao estado redox dos pacientes e as suas implicações para a patogênese da leishmaniose são discutidos.Visceral leishmaniasis (VL) is caused by obligatory intracellular protozoa belonging to Leishmania donovani (L. donovani) complex. The success in LV cure depends mainly on the immune status of the host in combination with the effects of antileishmanial drugs. Accordingly, leishmaniasis host resistance is associated with production of cytokines involved in Th1 response induction and its effector functions, such as IL-12, IFN-γ and TNF-α. This response culminates in macrophages activation, that begin to release higher levels of oxigen and nitrogen reactive species that have potent leishmanicidal activities. In contrast, susceptibility to infection and disease progression are linked to a predominat Th2 response that produces IL-4 and other cytokines such as IL-10 that deactivate macrophages. The importance of Th17 subset in host response to leishmania has also been studied, however it is not established yet if it is involved in resistance or susceptibility to infection. Despite these findings, few studies have aimed to evaluate the predominant profiles of CD4 + cells that are activated in patients with LV before and after treatment. Thus, one of the objectives of the present study was to quantify the cytokines tipical of Th1, Th2 and Th17 profiles in these two stages of disease progression. In addittion, we aimed to evaluate the redox status of these patients, since by trying to eliminate the parasite through the macrophage activation process, they can release excessive amounts of metabolites which may lead to oxidative stress involved in the pathogenesis of the disease. Patients before treatment trended to release higher IL-17 and IFN-γ in comparison to after treatment. Significant differences were detected in IL-6 and IL-10 levels. Patients before treatment presented higher production of both cytokines when compared to control subjects. However, after treatment, this production was significantly lowered, reaching levels similar to those of control subjects. Regarding redox state, patients with active disease exhibited an increase in the levels of malondialdehyde (MDA), an indicator of lipidic peroxidation, associated with a decrease in antioxidant carotenoids such as lycopene and lutein, which reveals the presence of an oxidative imbalance in these patients. Associations between immunological findings and those relating to the redox status of patients and their implications for the pathogenesis of leishmaniasis are discussed.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Crotalus durissus terrificus crotapotin naturally displays preferred positions for amino acid substitutions

<div><p>Abstract Background Classically, Crotalus durissus terrificus (Cdt) venom can be described, according to chromatographic criteria, as a simple venom, composed of four major toxins, namely: gyroxin, crotamine, crotoxin and convulxin. Crotoxin is a non-covalent heterodimeric neurotoxin constituted of two subunits: an active phospholipase A2 and a chaperone protein, termed crotapotin. This molecule is composed of three peptide chains connected by seven disulfide bridges. Naturally occurring variants/isoforms of either crotoxin or crotapotin itself have already been reported. Methods The crude Cdt venom was separated by using RP-HPLC and the toxins were identified by mass spectrometry (MS). Crotapotin was purified, reduced and alkylated in order to separate the peptide chains that were further analyzed by mass spectrometry and de novo peptide sequencing. Results The RP-HPLC profile of the isolated crotapotin chains already indicated that the α chain would present isoforms, which was corroborated by the MS and tandem mass spectrometry analyses. Conclusion It was possible to observe that the Cdt crotapotin displays a preferred amino acid substitution pattern present in the α chain, at positions 31 and 40. Moreover, substitutions could also be observed in β and γ chains (one for each). The combinations of these four different peptides, with the already described chains, would produce ten different crotapotins, which is compatible to our previous observations for the Cdt venom.</p></div

Single-Arm, Multicenter Phase I/II Clinical Trial for the Treatment of Envenomings by Massive Africanized Honey Bee Stings Using the Unique Apilic Antivenom

International audienceWe evaluated the safety, optimal dose, and preliminary effectiveness of a new-approach Africanized honeybee ( Apis mellifera ) Antivenom (AAV) in a phase I/II, multicenter, non-randomized, single-arm clinical trial involving 20 participants with multiple stings. Participants received 2 to 10 vials of AAV depending on the number of stings they suffered, or a predefined adjuvant, symptomatic, and complementary treatment. The primary safety endpoint was the occurrence of early adverse reactions within the first 24 h of treatment. Preliminary efficacy based on clinical evolution, including laboratory findings, was assessed at baseline and at various time points over the four following weeks. ELISA assays and mass spectrometry were used to estimate venom pharmacokinetics before, during, and after treatment. Twenty adult participants, i.e., 13 (65%) men and 7 (35%) women, with a median age of 44 years and a mean body surface area of 1.92 m 2 (median = 1.93 m 2 ) were recruited. The number of stings ranged from 7 to &gt; 2,000, with a median of 52.5. Symptoms of envenoming were classified as mild, moderate, or severe in 80% (16), 15% (3), and 5% (1) of patients, respectively; patients with mild, moderate, or severe envenoming received 2, 6, and 10 vials of AAV as per the protocol. None of the patients had late reactions (serum sickness) within 30 d of treatment. There was no discontinuation of the protocol due to adverse events, and there were no serious adverse events. One patient had a moderate adverse event, transient itchy skin, and erythroderma. All participants completed the intravenous antivenom infusion within 2 h, and there was no loss to follow-up after discharge. ELISA assays showed venom (melittin and PLA 2 ) concentrations varying between 0.25 and 1.479 ng/mL prior to treatment. Venom levels decreased in all patients during the hospitalization period. Surprisingly, in nine cases (45%), despite clinical recovery and the absence of symptoms, venom levels increased again during outpatient care 10 d after discharge. Mass spectrometry showed melittin in eight participants, 30 d after treatment. Considering the promising safety results for this investigational product in the treatment of massive Africanized honeybee attack, and its efficacy, reflected in the clinical improvements and corresponding immediate decrease in blood venom levels, the AAV has shown to be safe for human use. Clinical Trial Registration: UTN: U1111-1160-7011, identifier [RBR-3fthf8]