Different serological cross-reactivity of Trypanosoma rangeli forms in Trypanosoma cruzi-infected patients sera

<p>Abstract</p> <p>Background</p> <p>American Trypanosomiasis or Chagas disease is caused by <it>Trypanosoma cruzi </it>which currently infects approximately 16 million people in the Americas causing high morbidity and mortality. Diagnosis of American trypanosomiasis relies on serology, primarily using indirect immunofluorescence assay (IFA) with <it>T. cruzi </it>epimastigote forms. The closely related but nonpathogenic <it>Trypanosoma rangeli </it>has a sympatric distribution with <it>T. cruzi </it>and is carried by the same vectors. As a result false positives are frequently generated. This confounding factor leads to increased diagnostic test costs and where false positives are not caught, endangers human health due to the toxicity of the drugs used to treat Chagas disease.</p> <p>Results</p> <p>In the present study, serologic cross-reactivity between the two species was compared for the currently used epimastigote form and the more pathologically relevant trypomastigote form, using IFA and immunoblotting (IB) assays. Our results reveal an important decrease in cross reactivity when <it>T. rangeli </it>culture-derived trypomastigotes are used in IFA based diagnosis of Chagas disease. Western blot results using sera from both acute and chronic chagasic patients presenting with cardiac, indeterminate or digestive disease revealed similar, but not identical, antigenic profiles.</p> <p>Conclusion</p> <p>This is the first study addressing the serological cross-reactivity between distinct forms and strains of <it>T. rangeli </it>and <it>T. cruzi </it>using sera from distinct phases of the Chagasic infection. Several <it>T. rangeli</it>-specific proteins were detected, which may have potential as diagnostic tools.</p

Genome of the Avirulent Human-Infective Trypanosome—Trypanosoma rangeli

Background: Trypanosoma rangeli is a hemoflagellate protozoan parasite infecting humans and other wild and domestic mammals across Central and South America. It does not cause human disease, but it can be mistaken for the etiologic agent of Chagas disease, Trypanosoma cruzi. We have sequenced the T. rangeli genome to provide new tools for elucidating the distinct and intriguing biology of this species and the key pathways related to interaction with its arthropod and mammalian hosts.  Methodology/Principal Findings: The T. rangeli haploid genome is ,24 Mb in length, and is the smallest and least repetitive trypanosomatid genome sequenced thus far. This parasite genome has shorter subtelomeric sequences compared to those of T. cruzi and T. brucei; displays intraspecific karyotype variability and lacks minichromosomes. Of the predicted 7,613 protein coding sequences, functional annotations could be determined for 2,415, while 5,043 are hypothetical proteins, some with evidence of protein expression. 7,101 genes (93%) are shared with other trypanosomatids that infect humans. An ortholog of the dcl2 gene involved in the T. brucei RNAi pathway was found in T. rangeli, but the RNAi machinery is non-functional since the other genes in this pathway are pseudogenized. T. rangeli is highly susceptible to oxidative stress, a phenotype that may be explained by a smaller number of anti-oxidant defense enzymes and heatshock proteins.  Conclusions/Significance: Phylogenetic comparison of nuclear and mitochondrial genes indicates that T. rangeli and T. cruzi are equidistant from T. brucei. In addition to revealing new aspects of trypanosome co-evolution within the vertebrate and invertebrate hosts, comparative genomic analysis with pathogenic trypanosomatids provides valuable new information that can be further explored with the aim of developing better diagnostic tools and/or therapeutic targets

The Genomic Ancestry of Individuals from Different Geographical Regions of Brazil Is More Uniform Than Expected

Based on pre-DNA racial/color methodology, clinical and pharmacological trials have traditionally considered the different geographical regions of Brazil as being very heterogeneous. We wished to ascertain how such diversity of regional color categories correlated with ancestry. Using a panel of 40 validated ancestry-informative insertion-deletion DNA polymorphisms we estimated individually the European, African and Amerindian ancestry components of 934 self-categorized White, Brown or Black Brazilians from the four most populous regions of the Country. We unraveled great ancestral diversity between and within the different regions. Especially, color categories in the northern part of Brazil diverged significantly in their ancestry proportions from their counterparts in the southern part of the Country, indicating that diverse regional semantics were being used in the self-classification as White, Brown or Black. To circumvent these regional subjective differences in color perception, we estimated the general ancestry proportions of each of the four regions in a form independent of color considerations. For that, we multiplied the proportions of a given ancestry in a given color category by the official census information about the proportion of that color category in the specific region, to arrive at a “total ancestry” estimate. Once such a calculation was performed, there emerged a much higher level of uniformity than previously expected. In all regions studied, the European ancestry was predominant, with proportions ranging from 60.6% in the Northeast to 77.7% in the South. We propose that the immigration of six million Europeans to Brazil in the 19th and 20th centuries - a phenomenon described and intended as the “whitening of Brazil” - is in large part responsible for dissipating previous ancestry dissimilarities that reflected region-specific population histories. These findings, of both clinical and sociological importance for Brazil, should also be relevant to other countries with ancestrally admixed populations

NOx-, IL-1β-, TNF-α-, and IL-6-Inhibiting Effects and Trypanocidal Activity of Banana (Musa acuminata) Bracts and Flowers: UPLC-HRESI-MS Detection of Phenylpropanoid Sucrose Esters

Banana inflorescences are a byproduct of banana cultivation consumed in various regions of Brazil as a non-conventional food. This byproduct represents an alternative food supply that can contribute to the resolution of nutritional problems and hunger. This product is also used in Asia as a traditional remedy for the treatment of various illnesses such as bronchitis and dysentery. However, there is a lack of chemical and pharmacological data to support its consumption as a functional food. Therefore, this work aimed to study the anti-inflammatory action of Musa acuminata blossom by quantifying the cytokine levels (NOx, IL-1&beta;, TNF-&alpha;, and IL-6) in peritoneal neutrophils, and to study its antiparasitic activities using the intracellular forms of T. cruzi, L. amazonensis, and L. infantum. This work also aimed to establish the chemical profile of the inflorescence using UPLC-ESI-MS analysis. Flowers and the crude bract extracts were partitioned in dichloromethane and n-butanol to afford four fractions (FDCM, FNBU, BDCM, and BNBU). FDCM showed moderate trypanocidal activity and promising anti-inflammatory properties by inhibiting IL-1&beta;, TNF-&alpha;, and IL-6. BDCM significantly inhibited the secretion of TNF-&alpha;, while BNBU was active against IL-6 and NOx. LCMS data of these fractions revealed an unprecedented presence of arylpropanoid sucroses alongside flavonoids, triterpenes, benzofurans, stilbenes, and iridoids. The obtained results revealed that banana inflorescences could be used as an anti-inflammatory food ingredient to control inflammatory diseases

Synthesis of lupeol derivatives and their antileishmanial and antitrypanosomal activities

<p>The natural product lupeol <b>1</b> was isolated from aerial parts of <i>Vernonia scorpioides</i> with satisfactory yield, which made it viable to be used as starting material in semisynthetic approach. Ten lupeol derivatives <b>2–11</b> were prepared by classical procedures. Including, five new esters derivatives <b>7–11,</b> which were obtained by structural modifications in the isopropylidene fragment. All semisynthetic compounds and lupeol <b>1–11</b> were confirmed by ¹H NMR, ¹³C NMR and HRMS. Their antiprotozoal activity was evaluated <i>in vitro</i> against <i>L. amazonensis</i> and <i>T. cruzi.</i> Derivative <b>6</b> showed the best antitrypanosomal activity (IC₅₀ = 12.48 μg/mL) and the lowest cytotoxic derivative (CC₅₀ = 161.50 μg/mL). The mechanism of action of the most active derivatives (<b>4, 6</b> and <b>11</b>) is not dependent from the enzyme trypanothione reductase.</p

Nanoemulsions containing a synthetic chalcone as an alternative for treating cutaneous leshmaniasis : optimization using a full factorial design

Nanoemulsions are drug delivery systems that may increase the penetration of lipophilic compounds through the skin, enhancing their topical effect. Chalcones are compounds of low water solubility that have been described as promising molecules for the treatment of cutaneous leishmaniasis (CL). In this context, the aim of this work was to optimize the development of a nanoemulsion containing a synthetic chalcone for CL treatment using a 22 full factorial design. The formulations were prepared by spontaneous emulsification and the experimental design studied the influence of two independent variables (type of surfactant – soybean lecithin or sorbitan monooleate and type of co-surfactants – polysorbate 20 or polysorbate 80) on the physicochemical characteristics of the nanoemulsions, as well as on the skin permeation/retention of the synthetic chalcone in porcine skin. In order to evaluate the stability of the systems, the antileishmanial assay was performed against Leishmania amazonensis 24 hours and 60 days after the preparation of the nanoemulsions. The formulation composed of soybean lecithin and polysorbate 20 presented suitable physicochemical characteristics (droplet size 171.9 nm; polydispersity index 0.14; zeta potential -39.43 mV; pH 5.16; and viscosity 2.00 cP), drug content (91.09%) and the highest retention in dermis (3.03 μg⋅g-1) – the main response of interest – confirmed by confocal microscopy. This formulation also presented better stability of leishmanicidal activity in vitro against L. amazonensis amastigote forms (half maximal inhibitory concentration value 0.32±0.05 μM), which confirmed the potential of the nanoemulsion soybean lecithin and polysorbate 20 for CL treatment