Impact of autologous whole blood administration upon experimental mouse models of acute Trypanosoma cruzi infection

Autologous whole blood (AWB) administration is described as alternative/complementary medical practice widely employed in medical and veterinary therapy against infections, chronic pathologies and neoplasias. Our aim is to investigate in vivo biological effect of AWB using healthy murine models under the course of Trypanosoma cruzi acute infection. Methods: The first set of studies consisted of injecting different volumes of AWB and saline (SAL) into the posterior region of quadriceps muscle of healthy male Swiss mice under distinct therapeutic schemes evaluating: animal behavior, body and organ weight, hemogram, plasmatic biochemical markers for tissue damage and inflammatory cytokine levels and profile. To assess the impact on the experimental T. cruzi infection, different schemes (prior and post infection) and periods of AWB administration (from one up to 10 days) were conducted, also employing heterologous whole blood (HWB) and evaluating plasma cytokine profile. Results: No major adverse events were observed in healthy AWB-treated mice, except gait impairment in animals that received three doses of 20 µL AWB in the same hind limb. AWB and SAL triggered an immediate polymorphonuclear response followed by mononuclear infiltrate. Although SAL triggered an inflammatory response, the kinetics and intensity of the histological profile and humoral mediator levels were different from AWB, the latter occurring earlier and more intensely with concomitant elevation of plasma IL-6. Inflammatory peak response of SAL, mainly composed of mononuclear cells with IL-10, was increased at 24 h. According to the mouse model of acute T. cruzi infection, only minor decreases (< 30%) in the parasitemia levels were produced by AWB and HWB given before and after infection, without protecting against mortality. Rises in IFN-gamma, TNF-alpha and IL-6 were detected at 9 dpi in all infected animals as compared to uninfected mice but only Bz displayed a statistically significant diminution (p= 0.02) in TNF-alpha levels than infected and untreated mice. Conclusions: This study revealed that the use of autologous whole blood (AWB) in the acute model employed was unable to reduce the parasitic load of infected mice, providing only a minor decrease in parasitemia levels (up to 30%) but without protecting against animal mortality. Further in vivo studies will be necessary to elucidate the effective impact of this procedure.(AU)

Impact of autologous whole blood administration upon experimental mouse models of acute Trypanosoma cruzi infection

Background: Autologous whole blood (AWB) administration is described as alternative/complementary medical practice widely employed in medical and veterinary therapy against infections, chronic pathologies and neoplasias. Our aim is to investigate in vivo biological effect of AWB using healthy murine models under the course of Trypanosoma cruzi acute infection. Methods: The first set of studies consisted of injecting different volumes of AWB and saline (SAL) into the posterior region of quadriceps muscle of healthy male Swiss mice under distinct therapeutic schemes evaluating: animal behavior, body and organ weight, hemogram, plasmatic biochemical markers for tissue damage and inflammatory cytokine levels and profile. To assess the impact on the experimental T. cruzi infection, different schemes (prior and post infection) and periods of AWB administration (from one up to 10 days) were conducted, also employing heterologous whole blood (HWB) and evaluating plasma cytokine profile. Results: No major adverse events were observed in healthy AWB-treated mice, except gait impairment in animals that received three doses of 20 L AWB in the same hind limb. AWB and SAL triggered an immediate polymorphonuclear response followed by mononuclear infiltrate. Although SAL triggered an inflammatory response, the kinetics and intensity of the histological profile and humoral mediator levels were different from AWB, the latter occurring earlier and more intensely with concomitant elevation of plasma IL-6. Inflammatory peak response of SAL, mainly composed of mononuclear cells with IL-10, was increased at 24 h. According to the mouse model of acute T. cruzi infection, only minor decreases ( 30%) in the parasitemia levels were produced by AWB and HWB given before and after infection, without protecting against mortality. Rises in IFN-gamma, TNF-alpha and...

Uso da associação de Benznidazol e espironolactona em camundongos na fase aguda da infecção pelo Trypanosoma cruzi / The impact of the benznidazole and spironolactone combination in the evolution of the acute phase of Trypanosoma cruzi-infected mice

A doença de Chagas, causada pelo protozoário Trypanosoma cruzi, foi responsável por 4.916 óbitos no Brasil no ano de 2005, o que ressalta a importância de que se busquem novas formas de tratamento para esses pacientes. Estudos anteriores revelaram uma marcante lesão renal em camundongos infectados pelo T. cruzi nos estágios iniciais da infecção. Além disso, foi constatado que o bloqueiodas vias cardiovascular e renal (como o sistema renina angiotensina-aldosterona) diminuiu a mortalidade dos animais em 40por cento. Recentemente foi observado que o bloqueio de aldosterona minimiza a perda de potássio e os efeitos cardiovasculares da infecção pelo T. cruzi. O objetivodeste trabalho foi avaliar a eficiência da associação entre o benznidazol (Bz) e a espironolactona (Sp) na condição física dos camundongos infectados. Comparando os camundongos infectados e os tratados com Bz/Sp, observamos que a associação promove uma sobrevida de 100por cento, com ganho de peso, manutenção do consumo de alimentos e da atividade física dos animais. Em comparação com o tratamento somente com Bz, a combinação mantém níveis superiores das atividades motora e exploratória, principalmente no décimo quinto dia pós-infecção. Os dados sugerem, portanto, que a associação entre Bz e Sp apresenta uma benéfica influência na condição física dos camundongos durante a fase aguda experimental.

Acute experimental Trypanosoma cruzi infection: establishing a murine model that utilises non-invasive measurements of disease parameters

Trypanosoma cruzi infection has a large public health impact in Latin American countries. Although the transmission rates via blood transfusions and insect vectors have declined sharply in the past 20 years due to policies of the Southern Cone countries, a large number of people are still at risk for infection. Currently, no accepted experimental model or descriptions of the clinical signs that occur during the course of acute murine infection are available. The aim of this work was to use non-invasive methods to evaluate the clinical signs of Balb/c mice infected with the Y strain of T. cruzi. The infected mice displayed evident clinical changes beginning in the third week of infection. The mice were evaluated based on physical characteristics, spontaneous activity, exploratory behaviour and physiological alterations. We hope that the results presented in this report provide parameters that complement the effective monitoring of trypanocidal treatment and other interventions used to treat experimental Chagas disease.

Absence of Fas-L aggravates renal injury in acute Trypanosoma cruzi infection

Trypanosoma cruzi infection induces diverse alterations in immunocompetent cells and organs, myocarditis and congestive heart failure. However, the physiological network of disturbances imposed by the infection has not been addressed thoroughly. Regarding myocarditis induced by the infection, we observed in our previous work that Fas-L-/- mice (gld/gld) have very mild inflammatory infiltration when compared to BALB/c mice. However, all mice from both lineages die in the early acute phase. Therefore, in this work we studied the physiological connection relating arterial pressure, renal function/damage and cardiac insufficiency as causes of death. Our results show that a broader set of dysfunctions that could be classified as a cardio/anaemic/renal syndrome is more likely responsible for cardiac failure and death in both lineages. However, gld/gld mice had very early glomerular deposition of IgM and a more intense renal inflammatory response with reduced renal filtration, which is probably responsible for the premature death in the absence of significant myocarditis in gld/gld.

Participação da molécula Fas-L na miocardite aguda promovida pela infecção experimental pelo Trypanosoma cruzi: regulação inflamatória celular e evolução da insuficiência cardíaca / Participation of molecule Fas-L in the acute myocarditis promoted by the experimental infection for the Trypanosoma cruzi: cellular inflammatory regulation and evolution of the cardiac insufficiency

A molécula Fas-L é classicamente associada ao processo de apoptose e morte celular. Contudo, atualmente sabe-se que está envolvida também em vários mecanismos de regulação de imunidade adquirida e da resposta inflamatória, através de ativação celular e da secreção de fatores quimiotáticos, por exemplo. Além disso, esta molécula também parece estar envolvida na regulação sistêmica da função renal e cardíaca. Este trabalho tem o objetivo de estudar a importância da interação Fas/Fas-L na regulação inflamatória da miocardite aguda e também na evolução da insuficiência cardíaca em camundongos infectados pelo Trypanosoma cruzi. Nossos resultados com animais deficientes em Fas-L mostraram menor intensidade da miocardite aguda e, consequentemente, redução na morte de cardiomiócitos. No entanto, houve alta mortalidade desse s animais quando comparados com camundongos BALB/c. Observamos através de citometria de fluxo que na ausência da molécula há prevalência de linfócitos T CD4(mais) no tecido cardíaco e uma resposta mista Th1/Th2. Diferente dos animais selvagens infectados, que têm predomínio de células T CD8(mais) e perfil Th1. Aprofundamos o estudo sobre a causa da morte dos animais deficientes e observamos um comprometimento da função renal e cardíaca mais grave e mais precoce possivelmente relacionado ao óbvio. Além disso, houve alterações adicionais na pressão arterial, na condução elétrica cardíaca e na hematologia de ambas as linhagens. Concluímos assim que a molécula Fas-L não está diretamente envolvida na destruição de fibras musculares cardíacas, mas atua localmente regulando o equilíbrio e padrão de citocinas e infiltração inflamatória celular. Atua também de forma sistêmica promovendo uma insuficiência cardíaca fulminante por uma síndrome cardio-anêmica-renal.