RESUMO
Trichomonas vaginalis and Tritrichomonas foetus are parasitic, flagellated protists that inhabit the urogenital tract of humans and bovines, respectively. T. vaginalis causes the most prevalent non-viral sexually transmitted disease worldwide and has been associated with an increased risk for human immunodeficiency virus-1 infection in humans. Infections by T. foetus cause significant losses to the beef industry worldwide due to infertility and spontaneous abortion in cows. Several studies have shown a close association between trichomonads and the epithelium of the urogenital tract. However, little is known concerning the interaction of trichomonads with cells from deeper tissues, such as fibroblasts and muscle cells. Published parasite-host cell interaction studies have reported contradictory results regarding the ability of T. foetus and T. vaginalis to interact with and damage cells of different tissues. In this study, parasite-host cell interactions were examined by culturing primary human fibroblasts obtained from abdominal biopsies performed during plastic surgeries with trichomonads. In addition, mouse 3T3 fibroblasts, primary chick embryo myogenic cells and L6 muscle cells were also used as models of target cells. The parasite-host cell cultures were processed for scanning and transmission electron microscopy and were tested for cell viability and cell death. JC-1 staining, which measures mitochondrial membrane potential, was used to determine whether the parasites induced target cell damage. Terminal deoxynucleotidyltransferase-mediated dUTP nick end labelling staining was used as an indicator of chromatin damage. The colorimetric crystal violet assay was performed to ana-lyse the cytotoxicity induced by the parasite. The results showed that T. foetus and T. vaginalis adhered to and were cytotoxic to both fibroblasts and muscle cells, indicating that trichomonas infection of the connective and muscle tissues is likely to occur; such infections could cause serious risks to the infected host.
Assuntos
Adesão Celular/fisiologia , Fibroblastos/parasitologia , Interações Hospedeiro-Parasita/fisiologia , Células Musculares/parasitologia , Trichomonas vaginalis/fisiologia , Tritrichomonas foetus/fisiologia , Animais , Embrião de Galinha , Humanos , Marcação In Situ das Extremidades Cortadas , CamundongosRESUMO
Trichomonas vaginalis and Tritrichomonas foetus are parasitic, flagellated protists that inhabit the urogenital tract of humans and bovines, respectively. T. vaginalis causes the most prevalent non-viral sexually transmitted disease worldwide and has been associated with an increased risk for human immunodeficiency virus-1 infection in humans. Infections by T. foetus cause significant losses to the beef industry worldwide due to infertility and spontaneous abortion in cows. Several studies have shown a close association between trichomonads and the epithelium of the urogenital tract. However, little is known concerning the interaction of trichomonads with cells from deeper tissues, such as fibroblasts and muscle cells. Published parasite-host cell interaction studies have reported contradictory results regarding the ability of T. foetus and T. vaginalis to interact with and damage cells of different tissues. In this study, parasite-host cell interactions were examined by culturing primary human fibroblasts obtained from abdominal biopsies performed during plastic surgeries with trichomonads. In addition, mouse 3T3 fibroblasts, primary chick embryo myogenic cells and L6 muscle cells were also used as models of target cells. The parasite-host cell cultures were processed for scanning and transmission electron microscopy and were tested for cell viability and cell death. JC-1 staining, which measures mitochondrial membrane potential, was used to determine whether the parasites induced target cell damage. Terminal deoxynucleotidyltransferase-mediated dUTP nick end labelling staining was used as an indicator of chromatin damage. The colorimetric crystal violet assay was performed to ana-lyse the cytotoxicity induced by the parasite. The results showed that T. foetus and T. vaginalis adhered to and were cytotoxic to both fibroblasts and muscle cells, indicating that trichomonas infection of the connective and muscle tissues is likely to occur; such infections could cause serious risks to the infected host.
Assuntos
Animais , Embrião de Galinha , Humanos , Camundongos , Adesão Celular/fisiologia , Fibroblastos/parasitologia , Interações Hospedeiro-Parasita/fisiologia , Células Musculares/parasitologia , Trichomonas vaginalis/fisiologia , Tritrichomonas foetus/fisiologia , Marcação In Situ das Extremidades CortadasRESUMO
Gap junction channels provide intercellular communication between cells. In the heart, these channels coordinate impulse propagation along the conduction system and through the contractile musculature, thereby providing synchronous and optimal cardiac output. As in other arrhythmogenic cardiac diseases, chagasic cardiomyopathy is associated with decreased expression of the gap junction protein connexin43 (Cx43) and its gene. Our studies of cardiac myocytes infected with Trypanosoma cruzi have revealed that synchronous contraction is greatly impaired and gap junction immunoreactivity is lost in infected cells. Such changes are not seen for molecules forming tight junctions, another component of the intercalated disc in cardiac myocytes. Transcriptomic studies of hearts from mouse models of Chagas disease and from acutely infected cardiac myocytes in vitro indicate profound remodelling of gene expression patterns involving heart rhythm determinant genes, suggesting underlying mechanisms of the functional pathology. One curious feature of the altered expression of Cx43 and its gene expression is that it is limited in both extent and location, suggesting that the more global deterioration in cardiac function may result in part from spread of damage signals from more seriously compromised cells to healthier ones.
Assuntos
Cardiomiopatia Chagásica/parasitologia , Junções Comunicantes/fisiologia , Coração/fisiologia , Coração/parasitologia , Trypanosoma cruzi/patogenicidade , Animais , Células Cultivadas , Perfilação da Expressão Gênica , Interações Hospedeiro-Patógeno , Humanos , Camundongos , Células Musculares/parasitologia , Células Musculares/fisiologiaRESUMO
We describe some biological and molecular characteristics of a Trypanosoma cruzi isolate derived from a Triatomine captured in Nicaragua. PCR based typification showed that this isolate, named Nicaragua, belonged to the lineage Tc I. Nicaragua infected culture cells were treated with allopurinol, showing different behavior according to the cellular compartment, being cardiomyocyte primary cultures more resistant to this drug. The course of the infection in a mice experimental model and its susceptibility to benznidazole and allopurinol was analyzed. In benznidazole treatment, mice reverted the high lethal effect of parasites during the acute infection, however, a few parasites were detected in the heart of 88% of mice 1 year post-infection. Since T. cruzi is a heterogeneous species population it is important to study and characterize different parasites actually circulating in humans in endemic areas. In this work we show that T. cruzi Nicaragua isolate, is sensitive to early benznidazole treatment.
Assuntos
Doença de Chagas/epidemiologia , Doença de Chagas/parasitologia , Doenças Endêmicas , Tripanossomicidas/farmacologia , Trypanosoma cruzi/efeitos dos fármacos , Trypanosoma cruzi/fisiologia , Alopurinol/farmacologia , Alopurinol/uso terapêutico , Animais , Linhagem Celular , Células Cultivadas , Doença de Chagas/tratamento farmacológico , Concentração Inibidora 50 , Insetos Vetores/parasitologia , Camundongos , Camundongos Endogâmicos C3H , Células Musculares/parasitologia , Músculos/parasitologia , Músculos/patologia , Nicarágua/epidemiologia , Nitroimidazóis/farmacologia , Nitroimidazóis/uso terapêutico , Filogenia , Ratos , Triatoma/parasitologia , Tripanossomicidas/uso terapêutico , Trypanosoma cruzi/classificaçãoRESUMO
Chagas disease is caused by the parasite Trypanosoma cruzi. It is a common cause of heart disease in endemic areas of Latin America. The year 2009 marks the 100th anniversary of the discovery of T cruzi infection and Chagas disease by the Brazilian physician Carlos Chagas. Chagasic cardiomyopathy develops in from 10% to 30% of persons who are chronically infected with this parasite. Echocardiography and magnetic resonance imaging (MRI) are important modalities in the evaluation and prognostication of individuals with chagasic heart disease. The etiology of chagasic heart disease likely is multifactorial. Parasite persistence, autoimmunity, and microvascular abnormalities have been studied extensively as possible pathogenic mechanisms. Experimental studies suggest that alterations in cardiac gap junctions may be etiologic in the pathogenesis of conduction abnormalities. The diagnosis of chronic Chagas disease is made by serology. The treatment of this infection has shortcomings that need to be addressed. Cardiac transplantation and bone marrow stem cell therapy for persons with Chagas disease have received increasing research attention in recent years.
Assuntos
Cardiomiopatia Chagásica , Animais , Brasil , Cardiomiopatia Chagásica/diagnóstico por imagem , Cardiomiopatia Chagásica/epidemiologia , Cardiomiopatia Chagásica/imunologia , Cardiomiopatia Chagásica/parasitologia , Cardiomiopatia Chagásica/patologia , Doença de Chagas/epidemiologia , Doença de Chagas/parasitologia , Doenças Endêmicas/prevenção & controle , Doenças Endêmicas/estatística & dados numéricos , História do Século XIX , História do Século XX , Humanos , Estágios do Ciclo de Vida , Imageamento por Ressonância Magnética , Células Musculares/parasitologia , América do Sul/epidemiologia , Trypanosoma cruzi/crescimento & desenvolvimento , UltrassonografiaRESUMO
The anti-inflammatory cytokine, transforming growth factor beta (TGFbeta), plays an important role in Chagas disease, which is caused by the protozoan parasite Trypanosoma cruzi. In the current study, we show that the addition of an anti-TGFbeta antibody inhibited T. cruzi infection of cardiomyocytes, demonstrating the requirement for active endogenous TGFbeta. As TGFbeta is synthesized as a biologically inactive precursor, which is proteolytically processed to yield a mature, active homodimer, we hypothesized that T. cruzi could activate latent TGFbeta. To test this, we added recombinant latent TGFbeta to a TGFbeta-responsive reporter cell line in the presence of T. cruzi. We observed that T. cruzi was able to activate latent recombinant TGFbeta in this cellular model. We then investigated the ability of T. cruzi to activate latent TGFbetain vitro. We found that live T. cruzi, or cytosolic extracts of T. cruzi, activated latent TGFbeta in a dose- and temperature-dependent manner. The agent involved in TGFbeta activation was shown to be thermolabile and hydrophobic. Taken together, our studies demonstrate that T. cruzi directly activates latent TGFbeta. This activation is required for parasite entry into the mammalian cells and is likely to play an important role in modulating the outcome of T. cruzi infection.