C57BL/6 Mice Pretreated With Alpha-Tocopherol Show a Better Outcome of Trypanosoma cruzi Infection With Less Tissue Inflammation and Fibrosis.

Chagas disease is accompanied by a multisystem inflammatory disorder that follows Trypanosoma cruzi infection. Alpha-tocopherol has been described as an antioxidant and a potential adjuvant to enhance immune responses to vaccines. Therefore, we have evaluated the immune response to T. cruzi infection upon alpha-tocopherol pre-administration. The results show that administration of alpha-tocopherol before the infection results in lower parasitemia and lower mortality of C57BL/6 mice infected with the Tulahuen T. cruzi strain. Alpha-tocopherol administration in normal C57BL/6 mice resulted in higher levels of IFN-γ production by T and NK cells before and after the infection with T. cruzi. More importantly, previous administration of alpha-tocopherol increased the production of IL-10 by T and myeloid suppressor cells and the formation of effector memory T cells while decreasing the expression of PD-1 on T cells. These results suggest that alpha-tocopherol may limit the appearance of dysfunctional T cells during the acute and early chronic phases of T. cruzi infection, contributing to control infection. In addition, alpha-tocopherol could diminish tissue inflammation and fibrosis in late acute disease. These results strongly suggest that alpha-tocopherol may be a helpful agent to be considered in Chagas disease.

Análise histopatológica dos efeitos do bioterápico 200dh em camundongos infectados por Trypanosoma Cruzi / Histopathological analysis of the effects of 200dh biotherapeutic in mice infected with Trypanosoma Cruzi

O Trypanosoma cruzi é um protozoário que instaura uma infecção grave em seu hospedeiro vertebrado, podendo causar danos irreversíveis, principalmente em suas células musculares, conhecida como a doença tripanossomíase ou Doença de Chagas. dicação disponível no mercado, que combate esse parasito, não é completamente eficiente e produz danos indesejáveis e irreversíveis, fazendo-se necessário a busca por outros campos da medicina, em termos de medicação, para combater essa doença. Nesse sentido, pesquisas com medicamentos homeopáticos têm se revelado promissoras no combate ao parasito, sobretudo as formas amastigotas, que são mais difíceis de serem exterminadas. Os bioterápicos são os homeopáticos que obtiveram maior sucesso em relação à infecção por T. cruzi, uma vez que esses medicamentos possuem seu princípio ativo retirado do próprio parasito, suas toxinas, parte de membros, realizando uma terapia conhecida como isoterapia ­ cura pelo igual. Resultados encontrados indicam que o bioterápico 200dH atua coagindo o sistema imune a combater o T. cruzi em cobaias contaminadas, fomentando uma resposta imune celular e humoral mais eficiente do que a fisiológica. Acredita-se que esse medicamento atue estimulando as células de defesa, que passarão a responder de forma antígeno- -específico, favorecendo o combate de amastigotas. Esse processo, provavelmente, é iniciado pela estimulação do macrófago, que por sua vez, de acordo com os resultados encontrados, inicia uma cascata inflamatória, com predominância da via Th1, fomentando a produção de IL4, IL-10 e interferon, auxiliando no combate as amastigotas.

The trypanosoma cruzi is a protozoan that causes a serious infeccion in the vertebrate host, being capable of causing irreversible damages mainly in the muscle cells, also known as trypanosomiasis disease or Chagas Disease. The commercially available drug medication which fights this parasite is not completely efficient and causes undesirable and irreversible damages making it necessary to search for other fields of medicine in terms of medication to combat this disease. Therefore research with homeopathic medicines has being promising in the fight against the parasite, especially the amastigote forms, which are more difficult to be exterminated. Biotherapics are the homeopathic ones that have been more successful in relation to T. cruzi infection, since these drugs have their active principle removed from the parasite itself, its toxins, part of its members, performing a therapy known as isotherapy - cure by the same. The results indicates that the 200dH biotherapic acts by coercing the immune system to fight T. cruzi in contaminated guinea pigs, promoting a cellular and humoral imune response more efficient than the physiological one. It is believed that this medicine works by stimulating the defense cells which will respond in an antigen-specific manner favoring the fight against amastigotes. This process is probably initiated by the stimulation of the macrophage which in turn, according to the remains found, initiates an inflammatory cascade with predominance of the Th1 pathway, promoting the production of IL-4e IL-5 and interferon helping to combat amastigotes

Trypanocidal Activity of Four Sesquiterpene Lactones Isolated from Asteraceae Species.

The sesquiterpene lactones eupatoriopicrin, estafietin, eupahakonenin B and minimolide have been isolated from Argentinean Astearaceae species and have been found to be active against Trypanosoma cruzi epimastigotes. The aim of this work was to evaluate the activity of these compounds by analyzing their effect against the stages of the parasites that are infective for the human. Even more interesting, we aimed to determine the effect of the most active and selective compound on an in vivo model of T. cruzi infection. Eupatoriopicrin was the most active against amastigotes and tripomastigotes (IC50 = 2.3 µg/mL, and 7.2 µg/mL, respectively) and displayed a high selectivity index. This compound was selected to study on an in vivo model of T. cruzi infection. The administration of 1 mg/kg/day of eupatoriopicrin for five consecutive days to infected mice produced a significant reduction in the parasitaemia levels in comparison with non-treated animals (area under parasitaemia curves 4.48 vs. 30.47, respectively). Skeletal muscular tissues from eupatopicrin-treated mice displayed only focal and interstitial lymphocyte inflammatory infiltrates and small areas of necrotic; by contrast, skeletal tissues from T. cruzi infected mice treated with the vehicle showed severe lymphocyte inflammatory infiltrates with necrosis of the adjacent myocytes. The results indicate that eupatoriopicrin could be considered a promising candidate for the development of new therapeutic agents for Chagas disease.

Hybrid Molecules: Promising Compounds for the Development of New Treatments Against Leishmaniasis and Chagas Disease.

Leishmaniasis and Chagas disease are endemic pathologies in tropical countries. These cause high morbidity and a public health problem. Current chemotherapies are based on conventional drugs with variable efficacy and toxicity related with the length of therapeutic schemes and high doses. When two pharmacological agents are combined into a single molecule, the result is the so-called hybrid molecule. In the search for new treatments against Chagas disease and leishmaniasis, several studies have shown that hybrid molecules display high antiprotozoal activity and this emerging strategy is quite promising in the field of new drug discovery and development. This review focuses on the antiprotozoal activity of different hybrids obtained from the hybridization of pharmacophores, showing that the most of the efforts have been concentrated in the molecular hybridization of quinoline, chalcone and hydrazone moieties.

L-arginine supplementation reduces mortality and improves disease outcome in mice infected with Trypanosoma cruzi.

Chagas disease caused by Trypanosoma cruzi is a neglected disease that affects about 7 million people in Latin America, recently emerging on other continents due to migration. As infection in mice is characterized by depletion of plasma L-arginine, the effect on infection outcome was tested in mice with or without L-arginine supplementation and treatment with 1400W, a specific inhibitor of inducible nitric oxide synthase (iNOS). We found that levels of L-arginine and citrulline were reduced in the heart and plasma of infected mice, whereas levels of asymmetric dimethylarginine, an endogenous iNOS inhibitor, were higher. Moreover, L-arginine supplementation decreased parasitemia and heart parasite burden, improving clinical score and survival. Nitric oxide production in heart tissue and plasma was increased by L-arginine supplementation, while pharmacological inhibition of iNOS yielded an increase in parasitemia and worse clinical score. Interestingly, electrocardiograms improved in mice supplemented with L-arginine, suggesting that it modulates infection and heart function and is thus a potential biomarker of pathology. More importantly, L-arginine may be useful for treating T. cruzi infection, either alone or in combination with other antiparasitic drugs.

Phosphorus protects cardiac tissue by modifying the immune response in rats infected by Trypanosoma cruzi.

AIM: This study evaluates and correlates the number of myocarditis focuses and production of cytokines in Rattus norvegicus (Wistar lineage), experimentally infected with T. Cruzi and treated with Phosphorus. METHODS: In two blind, controlled and randomized trials, 53 45-day-old, male animals were allocated into groups Control (n=24): Control group infected and treated with 7% hydroalcoholic solution, the preparation vehicle of the test medication; and Phosphorus (n=24 on days 0, 5, 10 and 24 after infection): group infected and treated with Phosphorus 13cH, diluted 10-26 and dynamized (test medication). The animals were inoculated intraperitoneally with 5×106 blood trypomastigotes of T. cruzi-Y strain. The medication was administered overnight (16 consecutive hours), diluted in water (1mL/100mL) in amber water bottles. The animals were treated 2days before and 2, 4, and 6days after infection. Enumeration of inflammatory foci in cardiac tissue (Hematoxylin-Eosin) and dosage of cytokines TNF-α and IFN-γ in the serum were performed on days 0, 5, 10 and 24 after infection, using three animals/group. Mann-Whitney, Friedman ANOVA, Spearman correlation (p<0.05), and Statistica Single User Software version 13.2 were used for data analysis. RESULTS: The animals treated with Phosphorus 13cH had high concentration of INF-É£ on the 5th day of infection with significant decrease on the 10th and 24th days (p<0.05), and high concentration of TNF-α on the 5th and 10th days of infection with decrease on the 24th day (p<0.05). The treatment with Phosphorus caused a significant increase of INF-É£ and TNF-α on the 5th day of infection compared with the Control (p<0.05), with reestablishment on the 24th day, as well as in the Control group. The group treated with Phosphorus had 52.5% less number of myocarditis focuses in heart than Control group (p<0.05) on the 10th day of infection. The significant increase in cytokines on the5th day of infection in the Phosphorus group is related to a significant decrease in the number of inflammatory foci in cardiac tissue on the 10th day of infection in this group. DISCUSSION AND CONCLUSION: Treatment with Phosphorus 13cH promotes beneficial effects in T. cruzi infection in Wistar rats by modulating the secretion of IFN-γ and TNF-α with decreased inflammation in cardiac tissue. These results reinforce the importance of considering the use of homeopathy for establishing new therapeutic approaches in the management of patients with Chagas disease.

Antioxidant effect of Morus nigra on Chagas disease progression.

Considering the widespread popular use of Morus nigra and the amount of scientific information on its antioxidant and anti-inflammatory activity, the effectiveness of this phytotherapeutic compound in the parasitemia progression during the acute phase of Chagas disease and its role in the development of the inflammatory process as well as its effects on the oxidative damage in the chronic phase of infection were evaluated. Thus, 96 male Swiss mice were randomly divided into eight groups, four groups were uninfected controls, and four groups were intraperitoneally infected with 5.0 x 104 blood trypomastigotes forms of T. cruzi QM2 strain. Four batches composed of one uninfected and one infected group were respectively treated with 70% alcohol solution and 25 µL, 50 µL and 75 µL of the phytotherapeutic compound. Levels of antioxidant elements (TBARS, FRAP, GSH and Sulfhydryl groups) were measured in plasma samples. The phytotherapeutic compound's antioxidant activity was measured by polyphenol and total flavonoid quantification, DPPH, NO, and FRAP method. Our results showed that the vehicle influenced some of the results that may have physiological relevance in Chagas disease. However, an important action of M. nigra tincture was observed in the progression of Chagas disease, since our results demonstrated a reduction in parasitemia of treated groups when compared to controls, especially in the group receiving 25 µL. However, in the chronic phase, the 50-µL dosage presented a better activity on some antioxidant defenses and minimized the tissue inflammatory process. Results indicated an important action of M. nigra tincture on the Chagas disease progression.

Multi-Anti-Parasitic Activity of Arylidene Ketones and Thiazolidene Hydrazines against Trypanosoma cruzi and Leishmania spp.

A series of fifty arylideneketones and thiazolidenehydrazines was evaluated against Leishmania infantum and Leishmania braziliensis. Furthermore, new simplified thiazolidenehydrazine derivatives were evaluated against Trypanosoma cruzi. The cytotoxicity of the active compounds on non-infected fibroblasts or macrophages was established in vitro to evaluate the selectivity of their anti-parasitic effects. Seven thiazolidenehydrazine derivatives and ten arylideneketones had good activity against the three parasites. The IC50 values for T. cruzi and Leishmania spp. ranged from 90 nM-25 µM. Eight compounds had multi-trypanocidal activity against T. cruzi and Leishmania spp. (the etiological agents of cutaneous and visceral forms). The selectivity of these active compounds was better than the three reference drugs: benznidazole, glucantime and miltefosine. They also had low toxicity when tested in vivo on zebrafish. Trying to understand the mechanism of action of these compounds, two possible molecular targets were investigated: triosephosphate isomerase and cruzipain. We also used a molecular stripping approach to elucidate the minimal structural requirements for their anti-T. cruzi activity.

Different Therapeutic Outcomes of Benznidazole and VNI Treatments in Different Genders in Mouse Experimental Models of Trypanosoma cruzi Infection.

The lack of translation between preclinical assays and clinical trials for novel therapies for Chagas disease (CD) indicates a need for more feasible and standardized protocols and experimental models. Here, we investigated the effects of treatment with benznidazole (Bz) and with the potent experimental T. cruzi CYP51 inhibitor VNI in mouse models of Chagas disease by using different animal genders and parasite strains and employing distinct types of therapeutic schemes. Our findings confirm that female mice are less vulnerable to the infection than males, show that male models are less susceptible to treatment with both Bz and VNI, and thus suggest that male models are much more suitable for selection of the most promising antichagasic agents. Additionally, we have found that preventive protocols (compound given at 1 dpi) result in higher treatment success rates, which also should be avoided during advanced steps of in vivo trials of novel anti-T. cruzi drug candidates. Another consideration is the relevance of immunosuppression methods in order to verify the therapeutic profile of novel compounds, besides the usefulness of molecular diagnostic tools (quantitative PCR) to ascertain compound efficacy in experimental animals. Our study aims to contribute to the development of more reliable methods and decision gates for in vivo assays of novel antiparasitic compounds in order to move them from preclinical to clinical trials for CD.

EFFECTS OF VITAMIN C SUPPLEMENTATION ON THE CHRONIC PHASE OF CHAGAS DISEASE.

INTRODUCTION: In order to examine the effectiveness of vitamin C (ascorbic acid) in combating the oxidative insult caused by Trypanosoma cruzi during the development of the chronic phase of Chagas disease, Swiss mice were infected intraperitoneally with 5.0 × 104 trypomastigotes of T. cruzi QM1strain. METHODS: Mice were given supplements of two different doses of vitamin C for 180 days. Levels of lipid oxidation (as indicated by thiobarbituric acid reactive substances-TBARS), total peroxide, vitamin C, and reduced glutathione were measured in the plasma, TBARS, total peroxide and vitamin C were measured in the myocardium and histopathologic analysis was undertaken in heart, colon and skeletal muscle. RESULTS: Animals that received a dose equivalent to 500 mg of vitamin C daily showed increased production of ROS in plasma and myocardium and a greater degree of inflammation and necrosis in skeletal muscles than those that received a lower dose or no vitamin C whatsoever. CONCLUSION: Although some research has shown the antioxidant effect of vitamin C, the results showed that animals subject to a 500 mg dose of vitamin C showed greater tissue damage in the chronic phase of Chagas disease, probably due to the paradoxical actions of the substance, which in this pathology, will have acted as a pro-oxidant or pro-inflammatory.

Effects of vitaiin c supplementation on the chronic phase of chagas iisease / Efeitos da suplementação de vitamina C na fase crônica da doença de Chagas

Introduction: In order to examine the effectiveness of vitamin C (ascorbic acid) in combating the oxidative insult caused by Trypanosoma cruzi during the development of the chronic phase of Chagas disease, Swiss mice were infected intraperitoneally with 5.0 × 104 trypomastigotes of T. cruzi QM1strain. Methods: Mice were given supplements of two different doses of vitamin C for 180 days. Levels of lipid oxidation (as indicated by thiobarbituric acid reactive substances-TBARS), total peroxide, vitamin C, and reduced glutathione were measured in the plasma, TBARS, total peroxide and vitamin C were measured in the myocardium and histopathologic analysis was undertaken in heart, colon and skeletal muscle. Results: Animals that received a dose equivalent to 500 mg of vitamin C daily showed increased production of ROS in plasma and myocardium and a greater degree of inflammation and necrosis in skeletal muscles than those that received a lower dose or no vitamin C whatsoever. Conclusion: Although some research has shown the antioxidant effect of vitamin C, the results showed that animals subject to a 500 mg dose of vitamin C showed greater tissue damage in the chronic phase of Chagas disease, probably due to the paradoxical actions of the substance, which in this pathology, will have acted as a pro-oxidant or pro-inflammatory. .

Introdução: Para verificar a eficácia da vitamina C em combater o insulto oxidativo causado pelo Trypanosoma cruzi durante a evolução da fase crônica da doença de Chagas, camundongos Swiss foram previamente infectados via intraperitoneal com 5.0 × 104 tripomastigotas da cepa QM1 de T. cruzi. Métodos: Camundongos foram suplementados com duas diferentes doses de vitamina C por 180 dias. Foram mensurados os níveis de peroxidação lipídica (indicado por substâncias reativas ao ácido tiobarbitúrico-TBARS), peróxido total, vitamina C, e glutationa reduzida no plasma e TBARS, peróxido total e vitamina C no miocárdio, e foi realizado o estudo histopatológico em coração, cólon e músculo esquelético. Resultados: Animais que receberam diariamente uma dosagem equivalente a 500 mg de vitamina C apresentaram aumento na produção de ROS e RNS no plasma e no miocárdio e maior grau de inflamação e necrose em músculo esquelético em comparação àqueles que receberam doses menores ou nenhuma vitamina C. Conclusão: Embora muitas pesquisas tenham mostrado o efeito antioxidante da vitamina C, nossos resultados mostraram que os animais que foram expostos a 500 mg de vitamina C apresentaram maior dano tecidual na fase crônica da doença de Chagas, provavelmente devido a ações paradoxais desta substância, onde nesta patologia, poderá agir como pró-oxidante ou pró-inflamatória. .

Trypanosoma cruzi: biotherapy made from trypomastigote modulates the inflammatory response.

UNLABELLED: This study evaluates the effect of Trypanosoma cruzi biotherapy 17dH (BIOT) on mice of different ages, infected with the protozoa concerned. METHOD: Performing a blind, controlled, randomized by drawing experiment, 110 animals four or eight-week-old, Swiss, male mice were divided into infected control treated hydroalcoholic 7% (CI-4 = 34 or CI-8 = 21 animals) and infected control treated with biotherapy 17dH-0.2 mL/animal/20 consecutive days/oral regimen (BIOT-4 = 33 or BIOT-8 = 21 animals). Animals were inoculated intraperitoneally with 1400 trypomastigote, T. cruzi Y-strain. Parasitological, immunological and histopathologic parameters were evaluated statistically, using Statistica-8.0 and R 3.0.2 program to analysis of survival. The study was approved by the Ethics Committee for Animal Experimentation/UEM. RESULTS: Four-week-old mice showed no statistical difference in parasitemia (P = 0.5718) between the treated and control group. Eight-week-old mice from the treated group had a higher parasite peak (P = 0.0424) and higher parasitemia (P < 0.005) than the control. To both groups of 4 and 8 weeks of age, treated or untreated, survival of mice was higher in the treated group than in the control, although it was not statistically significant (p-value = 0.32, 0.55 respectively). Four-week-old mice displayed a spleen section with a number of amastigote nests significantly higher in BIOT-4 than CI-4 (P = 0.01). In eight-week-old mice the number of amastigote nests (P < 0.001) and inflammatory foci (P < 0.06-10% significance) in the liver section were smaller in BIOT-8 than CI-8. Spleen giant cells were significantly higher in CI-8 than in BIOT-8 (P < 0.01). Eight-week-old animals treated with biotherapy showed higher parasitemia and lower tissue parasitism. Opposite pattern was observed in four-week-old animals. CONCLUSION: There is a difference of high diluted medication effect in four and eight-week-old mice. In the group of animals 8 weeks the immunomodulatory effect seems to have been higher. Hence, treatment with the medicine produced from T. cruzi modulates the inflammatory response with increased apoptosis and decreased serum levels of TGF-ß.

PALEOPATHOLOGY OF PRE-COLUMBIAN MUMMIES AT THE MUSEUM OF ANTHROPOLOGY AND ETHNOLOGY IN FLORENCE.

We performed a histopathological study on the mummified tissue specimens of seven pre-Columbian mummies which arrived in Italy in the second half of the 19th century and are housed in the Section of Anthropology and Ethnology of the Museum of Natural History of the University of Florence. The results confirm that the modern techniques of pathological anatomy can be successfidly applied on mummifed tissues, so as to perform important paleopathological diagnoses. Among the results obtained from this study there is the only known complete paleopathological study of Chagas' disease (American Trypanosomiasis), comprising macroscopic, microscopic and ultrastructural data, as well as information on atherosclerosis, anthracosis, emphysema and pneumonia.

Antiparasitic activity of natural and semi-synthetic tirucallane triterpenoids from Schinus terebinthifolius (Anacardiaceae): structure/activity relationships.

Leishmaniasis and Chagas are diseases caused by parasitic protozoans that affect the poorest population in the World, causing a high mortality and morbidity. As a result of highly toxic and long-term treatments, the discovery of novel, safe and more efficacious drugs is essential. In this work, the in vitro antiparasitic activity and mammalian cytotoxicity of three natural tirucallane triterpenoids, isolated from leaves of Schinus terebinthifolius (Anacardiaceae), and nine semi-synthetic derivatives were investigated against Leishmania (L.) infantum and Trypanosoma cruzi. Trypomastigotes of T. cruzi were the most susceptible parasites and seven compounds demonstrated a trypanocidal activity with IC50 values in the range between 15 and 58 µg/mL. Four compounds demonstrated selectivity towards the intracellular amastigotes of Leishmania, with IC50 values in the range between 28 and 97 µg/mL. The complete characterization of triterpenoids was afforded after thorough analysis of nuclear magnetic resonance (NMR) data as well as electrospray ionization mass spectrometry (ESI-MS). Additionally, structure-activity relationships were performed using Decision Trees.

Trypanosoma cruzi infection in a non-endemic country: epidemiological and clinical profile.

Chagas disease has been increasingly diagnosed in non-endemic countries. This is a prospective observational study performed at the Tropical Medicine Units of the International Health Program of the Catalan Health Institute, Barcelona (PROgrama de Salud Internacional del Instituto Catalán de la Salud, PROSICS Barcelona, Spain), that includes all patients with Chagas disease who attended from June 2007 to May 2012. Clinical and epidemiological data were collected. Overall, 1274 patients were included, the mean age of the patients was 37.7 years, 67.5% were women and 97% came from Bolivia. Thirteen patients had immunosuppressive conditions. The prevalence of cardiac involvement was 16.9%, lower than in previous studies performed in endemic areas (20-60%). Cardiac alterations were found in 33.8% of symptomatic and 14.1% of asymptomatic patients. The prevalence of digestive involvement was 14.8%. The rate of digestive involvement is very different among previous studies because of different diagnostic tools and strategies used. Barium enema alterations were found in 21.4% of symptomatic and 10.3% of asymptomatic patients, and oesophageal alterations were found in 3.7% of symptomatic and in 2.3% of asymptomatic patients. As shown in previous studies, Chagas disease in non-endemic countries affects younger patients and has lower morbidity.

Assessment of the anti-protozoal activity of crude Carica papaya seed extract against Trypanosoma cruzi.

In order to determine the in vivo activity against the protozoan Trypanosoma cruzi, two doses (50 and 75 mg/kg) of a chloroform extract of Carica papaya seeds were evaluated compared with a control group of allopurinol. The activity of a mixture of the three main compounds (oleic, palmitic and stearic acids in a proportion of 45.9% of oleic acid, 24.1% of palmitic and 8.52% of stearic acid previously identified in the crude extract of C. papaya was evaluated at doses of 100, 200 and 300 mg/kg. Both doses of the extracts were orally administered for 28 days. A significant reduction (p < 0.05) in the number of blood trypomastigotes was observed in animals treated with the evaluated doses of the C. papaya extract in comparison with the positive control group (allopurinol 8.5 mg/kg). Parasitemia in animals treated with the fatty acids mixture was also significantly reduced (p < 0.05), compared to negative control animals. These results demonstrate that the fatty acids identified in the seed extracts of C. papaya (from ripe fruit) are able to reduce the number of parasites from both parasite stages, blood trypomastigote and amastigote (intracellular stage).

Evaluating Chagas disease progression and cure through blood-derived biomarkers: a systematic review.

This article reviews the usefulness of various types of blood-derived biomarkers that are currently being studied to predict the progression of Chagas disease in patients with the indeterminate form, to assess the efficacy of antiparasitic drugs and to identify early cardiac and gastrointestinal damage. The authors used a search strategy based on MEDLINE, Cochrane Library Register for systematic review, EmBase, Global Health and LILACS databases. Out of 1716 screened articles, only 166 articles were eligible for final inclusion. The authors classified the biomarkers according to their biochemical structure and primary biological activity in four groups: i) markers of inflammation and cellular injury, ii) metabolic biomakers, iii) prothrombotic biomarkers and iv) markers derived from specific antigens of the parasite. Several potential biomarkers might have clinical potential for the detection of early cardiopathy. Such capacity is imperative in order to detect high-risk patients who require intensive monitoring and earlier therapy. Prospective studies with longer follow-ups are needed for the appraisal of biomarkers assessing clinical or microbiological cure after therapy. At the same time, studies evaluating more than one biomarker are useful to compare the efficacy among them given the lack of a recognized gold standard.

Reciprocal influences between leptin and glucocorticoids during acute Trypanosoma cruzi infection.

Leptin and glucocorticoids (GCs) are involved in metabolic functions, thymic homeostasis and immune activity through complex interactions. We recently showed that C57BL/6 mice infected with Trypanosoma cruzi revealed a fatal disease associated with a dysregulated immune-endocrine response characterized by weight loss, deleterious synthesis of pro-inflammatory cytokines and GCs-driven thymus atrophy. Extending this study, we now explored the relationship between leptin and GCs, in terms of infection outcome, thymic and metabolic changes. T. cruzi-infected mice showed a food intake reduction, together with hypoglycemia and lipolysis-related changes. Infected animals also displayed a reduction in systemic and adipose tissue levels of leptin, paralleled by a down-regulation of their receptor (ObR) in the hypothalamus. Studies in infected mice subjected to adrenalectomy (Adx) showed a worsened course of infection accompanied by even more diminished systemic and intrathymic leptin levels, for which GCs are necessary not only to decrease inflammation but also to sustain leptin secretion. Adx also protected from thymic atrophy, independently of the reduced leptin contents. Leptin administration to infected mice aggravated inflammation, lowered parasite burden and attenuated GCs release, but did not normalize thymic atrophy or metabolic parameters. Acute T. cruzi infection in C57BL/6 mice coexists with a dysregulation of leptin/hypothalamic ObR circuitry dissociated from body weight and food intake control. Endogenous GCs production attempted to reestablish systemic leptin concentrations, but failed to improve leptin-protective activities at the thymic level, suggesting that the leptin/GCs intrathymic relationship is also altered during this infection.

Clomipramine and benznidazole association for the treatment of acute experimental Trypanosoma cruzi infection.

Alternative strategies are being designed to identify candidates among drugs already available on the market that could be used in combination to improve the efficacy of Chagas disease treatment. This work evaluates the effect of the association of clomipramine (CLO) with benznidazole (BZN) for the treatment of experimental Chagas disease in the acute stage, in Swiss albino mice infected with Trypanosoma cruzi Tulahuen strain. Infected mice were treated with CLO 5mg/kg/day and BZN 50 and 100mg/kg/day, each separately or together. Efficacy of the treatment was evaluated through parasitemia, survival, electrocardiography, histopathological studies, serological and PCR assays at 90 days post-infection (dpi). All treatments significantly (P<0.05) reduced mortality and decreased parasitemia. Histopathological analysis of liver and kidneys of mice treated with CLO and the drug combination showed less injury than mice treated only with BZN. The lower dose of BZN (50mg/kg/day) combined with CLO showed the same efficacy as the habitual dose of BZN (100mg/kg/day) combined with CLO. The therapeutic results from the combination of BZN with CLO presented lesser side effects than the treatment with BZN.

Further evidence of the trypanocidal action of eupomatenoid-5: confirmation of involvement of reactive oxygen species and mitochondria owing to a reduction in trypanothione reductase activity.

Our group assays natural products that are less toxic and more effective than available nitroheterocycles as promising therapeutic options for patients with Chagas disease. Our previous study reported the trypanocidal activity of eupomatenoid-5, a neolignan isolated from the leaves of Piper regnellii var. pallescens, against the three main parasitic forms of Trypanosoma cruzi. The present study further characterizes the biochemical and morphological alterations induced by this compound to elucidate the mechanisms of action involved in the cell death of T. cruzi. We show that eupomatenoid-5 induced oxidative imbalance in the three parasitic forms, especially trypomastigotes, reflected by a decrease in the activity of trypanothione reductase and increase in the formation of reactive oxygen species (ROS). A reduction of mitochondrial membrane potential was then triggered, further impairing the cell redox system through the production of more ROS and reactive nitrogen species. Altogether, these effects led to oxidative stress, reflected by lipid peroxidation and DNA fragmentation. These alterations are key events in the induction of parasite death through various pathways, including apoptosis, necrosis, and autophagy.