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1.
PLoS Pathog ; 19(11): e1011627, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37956215

RESUMO

Benznidazole is the front-line drug used to treat infections with Trypanosoma cruzi, the causative agent of Chagas disease. However, for reasons that are unknown, treatment failures are common. When we examined parasites that survived benznidazole treatment in mice using highly sensitive in vivo and ex vivo bioluminescence imaging, we found that recrudescence is not due to persistence of parasites in a specific organ or tissue that preferentially protects them from drug activity. Surviving parasites are widely distributed and located in host cells where the vast majority contained only one or two amastigotes. Therefore, infection relapse does not arise from a small number of intact large nests. Rather, persisters are either survivors of intracellular populations where co-located parasites have been killed, or amastigotes in single/low-level infected cells exist in a state where they are less susceptible to benznidazole. To better assess the nature of parasite persisters, we exposed infected mammalian cell monolayers to a benznidazole regimen that reduces the intracellular amastigote population to <1% of the pre-treatment level. Of host cells that remained infected, as with the situation in vivo, the vast majority contained only one or two surviving intracellular amastigotes. Analysis, based on non-incorporation of the thymidine analogue EdU, revealed these surviving parasites to be in a transient non-replicative state. Furthermore, treatment with benznidazole led to widespread parasite DNA damage. When the small number of parasites which survive in mice after non-curative treatment were assessed using EdU labelling, this revealed that these persisters were also initially non-replicative. A possible explanation could be that triggering of the T. cruzi DNA damage response pathway by the activity of benznidazole metabolites results in exit from the cell cycle as parasites attempt DNA repair, and that metabolic changes associated with non-proliferation act to reduce drug susceptibility. Alternatively, a small percentage of the parasite population may pre-exist in this non-replicative state prior to treatment.


Assuntos
Doença de Chagas , Nitroimidazóis , Parasitos , Tripanossomicidas , Trypanosoma cruzi , Animais , Camundongos , Trypanosoma cruzi/genética , Nitroimidazóis/farmacologia , Doença de Chagas/parasitologia , Dano ao DNA , Tripanossomicidas/farmacologia , Tripanossomicidas/metabolismo , Mamíferos
2.
PLoS Pathog ; 17(8): e1009864, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34424944

RESUMO

Digestive Chagas disease (DCD) is an enteric neuropathy caused by Trypanosoma cruzi infection. The mechanism of pathogenesis is poorly understood and the lack of a robust, predictive animal model has held back research. We screened a series of mouse models using gastrointestinal tracer assays and in vivo infection imaging systems to discover a subset exhibiting chronic digestive transit dysfunction and significant retention of faeces in both sated and fasted conditions. The colon was a specific site of both tissue parasite persistence, delayed transit and dramatic loss of myenteric neurons as revealed by whole-mount immunofluorescence analysis. DCD mice therefore recapitulated key clinical manifestations of human disease. We also exploited dual reporter transgenic parasites to home in on locations of rare chronic infection foci in the colon by ex vivo bioluminescence imaging and then used fluorescence imaging in tissue microdomains to reveal co-localisation of infection and enteric nervous system lesions. This indicates that long-term T. cruzi-host interactions in the colon drive DCD pathogenesis, suggesting that the efficacy of anti-parasitic chemotherapy against chronic disease progression warrants further pre-clinical investigation.


Assuntos
Doença de Chagas/complicações , Modelos Animais de Doenças , Trato Gastrointestinal/parasitologia , Pseudo-Obstrução Intestinal/patologia , Trypanosoma cruzi/patogenicidade , Animais , Doença de Chagas/parasitologia , Doença Crônica , Feminino , Pseudo-Obstrução Intestinal/etiologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C3H , Camundongos SCID
3.
PLoS Genet ; 16(12): e1009170, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33326438

RESUMO

Analysis of genetic polymorphism is a powerful tool for epidemiological surveillance and research. Powerful inference from pathogen genetic variation, however, is often restrained by limited access to representative target DNA, especially in the study of obligate parasitic species for which ex vivo culture is resource-intensive or bias-prone. Modern sequence capture methods enable pathogen genetic variation to be analyzed directly from host/vector material but are often too complex and expensive for resource-poor settings where infectious diseases prevail. This study proposes a simple, cost-effective 'genome-wide locus sequence typing' (GLST) tool based on massive parallel amplification of information hotspots throughout the target pathogen genome. The multiplexed polymerase chain reaction amplifies hundreds of different, user-defined genetic targets in a single reaction tube, and subsequent agarose gel-based clean-up and barcoding completes library preparation at under 4 USD per sample. Our study generates a flexible GLST primer panel design workflow for Trypanosoma cruzi, the parasitic agent of Chagas disease. We successfully apply our 203-target GLST panel to direct, culture-free metagenomic extracts from triatomine vectors containing a minimum of 3.69 pg/µl T. cruzi DNA and further elaborate on method performance by sequencing GLST libraries from T. cruzi reference clones representing discrete typing units (DTUs) TcI, TcIII, TcIV, TcV and TcVI. The 780 SNP sites we identify in the sample set repeatably distinguish parasites infecting sympatric vectors and detect correlations between genetic and geographic distances at regional (< 150 km) as well as continental scales. The markers also clearly separate TcI, TcIII, TcIV and TcV + TcVI and appear to distinguish multiclonal infections within TcI. We discuss the advantages, limitations and prospects of our method across a spectrum of epidemiological research.


Assuntos
Código de Barras de DNA Taxonômico/métodos , Genoma de Protozoário , Metagenoma , Metagenômica/métodos , Trypanosoma cruzi/genética , Sequenciamento Completo do Genoma/métodos , Animais , Custos e Análise de Custo , Código de Barras de DNA Taxonômico/economia , Código de Barras de DNA Taxonômico/normas , Vetores de Doenças , Hemípteros/parasitologia , Metagenômica/economia , Metagenômica/normas , Polimorfismo Genético , Trypanosoma cruzi/patogenicidade , Virulência/genética , Sequenciamento Completo do Genoma/economia , Sequenciamento Completo do Genoma/normas
4.
Infect Immun ; 90(2): e0038221, 2022 02 17.
Artigo em Inglês | MEDLINE | ID: mdl-34780279

RESUMO

Trypanosoma cruzi is the etiological agent of Chagas disease. Following T cell-mediated suppression of acute-phase infection, this intracellular eukaryotic pathogen persists long-term in a limited subset of tissues at extremely low levels. The reasons for this tissue-specific chronicity are not understood. Using a dual bioluminescent-fluorescent reporter strain and highly sensitive tissue imaging that allows experimental infections to be monitored at single-cell resolution, we undertook a systematic analysis of the immunological microenvironments of rare parasitized cells in the mouse colon, a key site of persistence. We demonstrate that incomplete recruitment of T cells to a subset of colonic infection foci permits the occurrence of repeated cycles of intracellular parasite replication and differentiation to motile trypomastigotes at a frequency sufficient to perpetuate chronic infections. The lifelong persistence of parasites in this tissue site continues despite the presence, at a systemic level, of a highly effective T cell response. Overcoming this low-level dynamic host-parasite equilibrium represents a major challenge for vaccine development.


Assuntos
Doença de Chagas , Trypanosoma cruzi , Animais , Doença de Chagas/parasitologia , Colo , Camundongos , Linfócitos T , Trypanosoma cruzi/fisiologia
5.
PLoS Pathog ; 16(4): e1008456, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32282850

RESUMO

Leishmania donovani causes visceral leishmaniasis (VL), which is typically fatal without treatment. There is substantial variation between individuals in rates of disease progression, response to treatment and incidence of post-treatment sequelae, specifically post-kala-azar dermal leishmaniasis (PKDL). Nevertheless, the majority of infected people are asymptomatic carriers. Hamsters and mice are commonly used as models of fatal and non-fatal VL, respectively. Host and parasite genetics are likely to be important factors, but in general the reasons for heterogeneous disease presentation in humans and animal models are poorly understood. Host microbiota has become established as a factor in cutaneous forms of leishmaniasis but this has not been studied in VL. We induced intestinal dysbiosis in mice and hamsters by long-term treatment with broad-spectrum antibiotics in their drinking water. There were no significant differences in disease presentation in dysbiotic mice. In contrast, dysbiotic hamsters infected with L. donovani had delayed onset and progression of weight loss. Half of control hamsters had a rapid progression phenotype compared with none of the ABX-treated animals and the nine-month survival rate was significantly improved compared to untreated controls (40% vs. 10%). Antibiotic-treated hamsters also had significantly less severe hepatosplenomegaly, which was accompanied by a distinct cytokine gene expression profile. The protective effect was not explained by differences in parasite loads or haematological profiles. We further found evidence that the gut-liver axis is a key aspect of fatal VL progression in hamsters, including intestinal parasitism, bacterial translocation to the liver, malakoplakia and iron sequestration, none of which occurred in non-progressing murine VL. Diverse bacterial genera were cultured from VL affected livers, of which Rodentibacter was specifically absent from ABX-treated hamsters, indicating this pathobiont may play a role in promoting disease progression. The results provide experimental support for antibiotic prophylaxis against secondary bacterial infections as an adjunct therapy in human VL patients.


Assuntos
Antibacterianos/administração & dosagem , Infecções Bacterianas/prevenção & controle , Coinfecção/prevenção & controle , Enteropatias Parasitárias/parasitologia , Leishmaniose Visceral/parasitologia , Animais , Antibioticoprofilaxia , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Fenômenos Fisiológicos Bacterianos , Coinfecção/microbiologia , Cricetinae , Progressão da Doença , Feminino , Microbioma Gastrointestinal , Humanos , Leishmania donovani/fisiologia , Leishmaniose Visceral/complicações , Masculino , Mesocricetus , Camundongos , Camundongos Endogâmicos C57BL , Simbiose
6.
Parasite Immunol ; 43(2): e12786, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-32799361

RESUMO

Trypanosoma cruzi is a remarkably versatile parasite. It can parasitize almost any nucleated cell type and naturally infects hundreds of mammal species across much of the Americas. In humans, it is the cause of Chagas disease, a set of mainly chronic conditions predominantly affecting the heart and gastrointestinal tract, which can progress to become life threatening. Yet around two thirds of infected people are long-term asymptomatic carriers. Clinical outcomes depend on many factors, but the central determinant is the nature of the host-parasite interactions that play out over the years of chronic infection in diverse tissue environments. In this review, we aim to integrate recent developments in the understanding of the spatial and temporal dynamics of T. cruzi infections with established and emerging concepts in host immune responses in the corresponding phases and tissues.


Assuntos
Portador Sadio/imunologia , Doença de Chagas/imunologia , Interações Hospedeiro-Parasita , Trypanosoma cruzi/imunologia , Animais , Anticorpos/imunologia , Portador Sadio/parasitologia , Humanos , Imunidade Celular , Transdução de Sinais
7.
Molecules ; 25(12)2020 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-32560454

RESUMO

The protozoan parasite Trypanosoma cruzi causes Chagas disease, an important public health problem throughout Latin America. Current therapeutic options are characterised by limited efficacy, long treatment regimens and frequent toxic side-effects. Advances in this area have been compromised by gaps in our knowledge of disease pathogenesis, parasite biology and drug activity. Nevertheless, several factors have come together to create a more optimistic scenario. Drug-based research has become more systematic, with increased collaborations between the academic and commercial sectors, often within the framework of not-for-profit consortia. High-throughput screening of compound libraries is being widely applied, and new technical advances are helping to streamline the drug development pipeline. In addition, drug repurposing and optimisation of current treatment regimens, informed by laboratory research, are providing a basis for new clinical trials. Here, we will provide an overview of the current status of Chagas disease drug development, highlight those areas where progress can be expected, and describe how fundamental research is helping to underpin the process.


Assuntos
Doença de Chagas/tratamento farmacológico , Desenvolvimento de Medicamentos , Descoberta de Drogas , Tripanossomicidas , Trypanosoma cruzi/metabolismo , Animais , Doença de Chagas/metabolismo , Doença de Chagas/parasitologia , Humanos , Tripanossomicidas/química , Tripanossomicidas/uso terapêutico
8.
Artigo em Inglês | MEDLINE | ID: mdl-30082291

RESUMO

Chagasic heart disease develops in 30% of those infected with the protozoan parasite Trypanosoma cruzi, but can take decades to become symptomatic. Because of this, it has been difficult to assess the extent to which antiparasitic therapy can prevent the development of pathology. We sought to address this question using experimental murine models, exploiting highly sensitive bioluminescent imaging to monitor curative efficacy. Mice were inoculated with bioluminescent parasites and then cured in either the acute or chronic stage of infection with benznidazole. At the experimental endpoint (5 to 6 months postinfection), heart tissue was removed and assessed for inflammation and fibrosis, two widely used markers of cardiac pathology. Infection of BALB/c and C3H/HeN mice with distinct T. cruzi lineages resulted in greatly increased myocardial collagen content at a group level, indicative of fibrotic pathology. When mice were cured by benznidazole in the acute stage, the development of pathology was completely blocked. However, if treatment was delayed until the chronic stage, cardiac fibrosis was observed in the BALB/c model, although the protective effect was maintained in the case of C3H/HeN mice. These experiments therefore demonstrate that curative benznidazole treatment early in murine T. cruzi infections can prevent the development of cardiac fibrosis. They also show that treatment during the chronic stage can block pathology but the effectiveness varies between infection models. If these findings are extendable to humans, it implies that widespread chemotherapeutic intervention targeted at early-stage infections could play a crucial role in reducing Chagas disease morbidity at a population level.


Assuntos
Doença de Chagas/tratamento farmacológico , Nitroimidazóis/uso terapêutico , Tripanossomicidas/uso terapêutico , Trypanosoma cruzi/efeitos dos fármacos , Trypanosoma cruzi/patogenicidade , Animais , Cardiomiopatia Chagásica/tratamento farmacológico , Modelos Animais de Doenças , Feminino , Coração/parasitologia , Inflamação/tratamento farmacológico , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C3H , Miocárdio/patologia
9.
Cell Microbiol ; 18(10): 1429-43, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-26918803

RESUMO

Host and parasite diversity are suspected to be key factors in Chagas disease pathogenesis. Experimental investigation of underlying mechanisms is hampered by a lack of tools to detect scarce, pleiotropic infection foci. We developed sensitive imaging models to track Trypanosoma cruzi infection dynamics and quantify tissue-specific parasite loads, with minimal sampling bias. We used this technology to investigate cardiomyopathy caused by highly divergent parasite strains in BALB/c, C3H/HeN and C57BL/6 mice. The gastrointestinal tract was unexpectedly found to be the primary site of chronic infection in all models. Immunosuppression induced expansion of parasite loads in the gut and was followed by widespread dissemination. These data indicate that differential immune control of T. cruzi occurs between tissues and shows that the large intestine and stomach provide permissive niches for active infection. The end-point frequency of heart-specific infections ranged from 0% in TcVI-CLBR-infected C57BL/6 to 88% in TcI-JR-infected C3H/HeN mice. Nevertheless, infection led to fibrotic cardiac pathology in all models. Heart disease severity was associated with the model-dependent frequency of dissemination outside the gut and inferred cumulative heart-specific parasite loads. We propose a model of cardiac pathogenesis driven by periodic trafficking of parasites into the heart, occurring at a frequency determined by host and parasite genetics.


Assuntos
Cardiomiopatias/parasitologia , Doença de Chagas/parasitologia , Trypanosoma cruzi/genética , AMP Desaminase , Animais , Cardiomiopatias/genética , Doença de Chagas/genética , Feminino , Trato Gastrointestinal/parasitologia , Genes de Protozoários , Variação Genética , Interações Hospedeiro-Parasita , Masculino , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BL , Camundongos SCID , Miocárdio/patologia
10.
Parasitology ; 144(14): 1871-1880, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28831944

RESUMO

Chagas disease is caused by infection with the insect-transmitted protozoan Trypanosoma cruzi, and is the most important parasitic infection in Latin America. The current drugs, benznidazole and nifurtimox, are characterized by limited efficacy and toxic side-effects, and treatment failures are frequently observed. The urgent need for new therapeutic approaches is being met by a combined effort from the academic and commercial sectors, together with major input from not-for-profit drug development consortia. With the disappointing outcomes of recent clinical trials against chronic Chagas disease, it has become clear that an incomplete understanding of parasite biology and disease pathogenesis is impacting negatively on the development of more effective drugs. In addition, technical issues, including difficulties in establishing parasitological cure in both human patients and animal models, have greatly complicated the assessment of drug efficacy. Here, we outline the major questions that need to be addressed and discuss technical innovations that can be exploited to accelerate the drug development pipeline.


Assuntos
Doença de Chagas/tratamento farmacológico , Descoberta de Drogas , Tripanossomicidas/uso terapêutico , Fatores Biológicos/farmacologia , Fatores Biológicos/uso terapêutico , Tripanossomicidas/farmacologia , Trypanosoma cruzi/efeitos dos fármacos
11.
Parasitology ; 144(7): 884-898, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28179034

RESUMO

Active Trypanosoma cruzi transmission persists in the Gran Chaco region, which is considered hyperendemic for Chagas disease. Understanding domestic and sylvatic transmission cycles and therefore the relationship between vectors and mammalian hosts is crucial to designing and implementing improved effective control strategies. Here we describe the species of triatomine vectors and the sylvatic mammal reservoirs of T. cruzi, in different localities of the Paraguayan and Bolivian Chaco. We identify the T. cruzi genotypes discrete typing units (DTUs) and provide a map of their geographical distribution. A total of 1044 triatomines and 138 sylvatic mammals were captured. Five per cent of the triatomines were microscopically positive for T. cruzi (55 Triatoma infestans from Paraguay and one sylvatic Triatoma guasayana from Bolivia) and 17 animals (12·3%) comprising eight of 28 (28·5%) Dasypus novemcinctus, four of 27 (14·8%) Euphractus sexcinctus, three of 64 (4·7%) Chaetophractus spp. and two of 14 (14·3%) Didelphis albiventris. The most common DTU infecting domestic triatomine bugs was TcV (64%), followed by TcVI (28%), TcII (6·5%) and TcIII (1·5%). TcIII was overwhelmingly associated with armadillo species. We confirm the primary role of T. infestans in domestic transmission, armadillo species as the principal sylvatic hosts of TcIII, and consider the potential risk of TcIII as an agent of Chagas disease in the Chaco.


Assuntos
Tatus , Doença de Chagas/veterinária , Didelphis , Triatominae/fisiologia , Triatominae/parasitologia , Trypanosoma cruzi/fisiologia , Animais , Biota , Doença de Chagas/epidemiologia , Doença de Chagas/parasitologia , Feminino , Genótipo , Masculino , Paraguai/epidemiologia , Triatominae/classificação , Trypanosoma cruzi/genética
12.
J Am Coll Nutr ; 35(5): 469-75, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-27454858

RESUMO

Traumatic brain injury (TBI), with its diverse heterogeneity and prolonged secondary pathogenesis, remains a clinical challenge. Clinical studies thus far have failed to identify an effective treatment strategy when a combination of targets controlling aspects of neuroprotection, neuroinflammation, and neuroregeneration is needed. Omega-3 fatty acids (n-3FA) offer the advantage of this approach. Although further clinical trial research is needed, there is a growing body of strong preclinical evidence and clinical experience that suggests that benefits may be possible from aggressively adding substantial amounts of n-3FA to optimize the nutritional foundation of TBI, concussion, and postconcussion syndrome patients. Early and optimal doses of n-3FA, even in a prophylactic setting, have the potential to improve outcomes from this potentially devastating problem. With evidence of unsurpassed safety and tolerability, n-3FA should be considered mainstream, conventional medicine, if conventional medicine can overcome its inherent bias against nutritional, nonpharmacologic therapies.


Assuntos
Concussão Encefálica/tratamento farmacológico , Lesões Encefálicas Traumáticas/tratamento farmacológico , Ácidos Graxos Ômega-3/uso terapêutico , Encéfalo/fisiopatologia , Concussão Encefálica/fisiopatologia , Lesões Encefálicas Traumáticas/fisiopatologia , Ácidos Graxos Ômega-3/efeitos adversos , Ácidos Graxos Ômega-3/fisiologia , Humanos , Terapia Nutricional
13.
Antimicrob Agents Chemother ; 59(8): 4653-61, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26014936

RESUMO

The antifungal drug posaconazole has shown significant activity against Trypanosoma cruzi in vitro and in experimental murine models. Despite this, in a recent clinical trial it displayed limited curative potential. Drug testing is problematic in experimental Chagas disease because of difficulties in demonstrating sterile cure, particularly during the chronic stage of infection when parasite burden is extremely low and tissue distribution is ill defined. To better assess posaconazole efficacy against acute and chronic Chagas disease, we have exploited a highly sensitive bioluminescence imaging system which generates data with greater accuracy than other methods, including PCR-based approaches. Mice inoculated with bioluminescent T. cruzi were assessed by in vivo and ex vivo imaging, with cyclophosphamide-induced immunosuppression used to enhance the detection of relapse. Posaconazole was found to be significantly inferior to benznidazole as a treatment for both acute and chronic T. cruzi infections. Whereas 20 days treatment with benznidazole was 100% successful in achieving sterile cure, posaconazole failed in almost all cases. Treatment of chronic infections with posaconazole did however significantly reduce infection-induced splenomegaly, even in the absence of parasitological cure. The imaging-based screening system also revealed that adipose tissue is a major site of recrudescence in mice treated with posaconazole in the acute, but not the chronic stage of infection. This in vivo screening model for Chagas disease is predictive, reproducible and adaptable to diverse treatment schedules. It should provide greater assurance that drugs are not advanced prematurely into clinical trial.


Assuntos
Antifúngicos/farmacologia , Doença de Chagas/tratamento farmacológico , Doença Crônica/tratamento farmacológico , Triazóis/farmacologia , Tripanossomicidas/farmacologia , Trypanosoma cruzi/efeitos dos fármacos , Animais , Doença de Chagas/parasitologia , Modelos Animais de Doenças , Feminino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos SCID , Nitroimidazóis/farmacologia
14.
Cell Microbiol ; 16(9): 1285-300, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24712539

RESUMO

Chronic Trypanosoma cruzi infections lead to cardiomyopathy in 20-30% of cases. A causal link between cardiac infection and pathology has been difficult to establish because of a lack of robust methods to detect scarce, focally distributed parasites within tissues. We developed a highly sensitive bioluminescence imaging system based on T. cruzi expressing a novel luciferase that emits tissue-penetrating orange-red light. This enabled long-term serial evaluation of parasite burdens in individual mice with an in vivo limit of detection of significantly less than 1000 parasites. Parasite distributions during chronic infections were highly focal and spatiotemporally dynamic, but did not localize to the heart. End-point ex vivo bioluminescence imaging allowed tissue-specific quantification of parasite loads with minimal sampling bias. During chronic infections, the gastro-intestinal tract, specifically the colon and stomach, was the only site where T. cruzi infection was consistently observed. Quantitative PCR-inferred parasite loads correlated with ex vivo bioluminescence and confirmed the gut as the parasite reservoir. Chronically infected mice developed myocarditis and cardiac fibrosis, despite the absence of locally persistent parasites. These data identify the gut as a permissive niche for long-term T. cruzi infection and show that canonical features of Chagas disease can occur without continual myocardium-specific infection.


Assuntos
Doença de Chagas/fisiopatologia , Doença de Chagas/parasitologia , Cardiopatias/fisiopatologia , Cardiopatias/parasitologia , Trypanosoma cruzi/fisiologia , Animais , Doença de Chagas/metabolismo , Feminino , Cardiopatias/metabolismo , Medições Luminescentes , Camundongos , Camundongos Endogâmicos BALB C , Reação em Cadeia da Polimerase
15.
PLoS Negl Trop Dis ; 18(6): e0012278, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38905323

RESUMO

Chagas disease is a zoonosis caused by the protozoan parasite Trypanosoma cruzi. Clinical outcomes range from long-term asymptomatic carriage to cardiac, digestive, neurological and composite presentations that can be fatal in both acute and chronic stages of the disease. Studies of T. cruzi in animal models, principally mice, have informed our understanding of the biological basis of this variability and its relationship to infection and host response dynamics. Hamsters have higher translational value for many human infectious diseases, but they have not been well developed as models of Chagas disease. We transposed a real-time bioluminescence imaging system for T. cruzi infection from mice into female Syrian hamsters (Mesocricetus auratus). This enabled us to study chronic tissue pathology in the context of spatiotemporal infection dynamics. Acute infections were widely disseminated, whereas chronic infections were almost entirely restricted to the skin and subcutaneous adipose tissue. Neither cardiac nor digestive tract disease were reproducible features of the model. Skeletal muscle had only sporadic parasitism in the chronic phase, but nevertheless displayed significant inflammation and fibrosis, features also seen in mouse models. Whereas mice had normal locomotion, all chronically infected hamsters developed hindlimb muscle hypertonia and a gait dysfunction resembling spastic diplegia. With further development, this model may therefore prove valuable in studies of peripheral nervous system involvement in Chagas disease.


Assuntos
Doença de Chagas , Modelos Animais de Doenças , Mesocricetus , Trypanosoma cruzi , Animais , Doença de Chagas/patologia , Doença de Chagas/parasitologia , Trypanosoma cruzi/fisiologia , Feminino , Camundongos , Cricetinae , Músculo Esquelético/parasitologia , Músculo Esquelético/patologia , Medições Luminescentes
16.
PLoS Negl Trop Dis ; 18(5): e0012106, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38820564

RESUMO

Chagas disease is caused by Trypanosoma cruzi, a protozoan parasite that displays considerable genetic diversity. Infections result in a range of pathological outcomes, and different strains can exhibit a wide spectrum of anti-parasitic drug tolerance. The genetic determinants of infectivity, virulence and therapeutic susceptibility remain largely unknown. As experimental tools to address these issues, we have generated a panel of bioluminescent:fluorescent parasite strains that cover the diversity of the T. cruzi species. These reporters allow spatio-temporal infection dynamics in murine models to be monitored in a non-invasive manner by in vivo imaging, provide a capability to detect rare infection foci at single-cell resolution, and represent a valuable resource for investigating virulence and host:parasite interactions at a mechanistic level. Importantly, these parasite reporter strains can also contribute to the Chagas disease drug screening cascade by ensuring that candidate compounds have pan-species in vivo activity prior to being advanced into clinical testing. The parasite strains described in this paper are available on request.


Assuntos
Doença de Chagas , Trypanosoma cruzi , Trypanosoma cruzi/genética , Trypanosoma cruzi/efeitos dos fármacos , Doença de Chagas/parasitologia , Animais , Camundongos , Genótipo , Modelos Animais de Doenças , Variação Genética , Fenótipo , Medições Luminescentes/métodos , Genes Reporter , Humanos , Feminino , Interações Hospedeiro-Parasita
17.
Nat Commun ; 15(1): 4400, 2024 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-38782898

RESUMO

Digestive Chagas disease (DCD) is an enteric neuropathy caused by Trypanosoma cruzi infection. There is a lack of evidence on the mechanism of pathogenesis and rationales for treatment. We used a female C3H/HeN mouse model that recapitulates key clinical manifestations to study how infection dynamics shape DCD pathology and the impact of treatment with the front-line, anti-parasitic drug benznidazole. Curative treatment 6 weeks post-infection resulted in sustained recovery of gastrointestinal transit function, whereas treatment failure led to infection relapse and gradual return of DCD symptoms. Neuro/immune gene expression patterns shifted from chronic inflammation to a tissue repair profile after cure, accompanied by increased cellular proliferation, glial cell marker expression and recovery of neuronal density in the myenteric plexus. Delaying treatment until 24 weeks post-infection led to partial reversal of DCD, suggesting the accumulation of permanent tissue damage over the course of chronic infection. Our study shows that murine DCD pathogenesis is sustained by chronic T. cruzi infection and is not an inevitable consequence of acute stage denervation. The risk of irreversible enteric neuromuscular tissue damage and dysfunction developing highlights the importance of prompt diagnosis and treatment. These findings support the concept of treating asymptomatic, T. cruzi-infected individuals with benznidazole to prevent DCD development.


Assuntos
Doença de Chagas , Modelos Animais de Doenças , Sistema Nervoso Entérico , Camundongos Endogâmicos C3H , Nitroimidazóis , Tripanossomicidas , Trypanosoma cruzi , Animais , Doença de Chagas/tratamento farmacológico , Doença de Chagas/parasitologia , Feminino , Tripanossomicidas/farmacologia , Tripanossomicidas/uso terapêutico , Nitroimidazóis/farmacologia , Nitroimidazóis/uso terapêutico , Trypanosoma cruzi/efeitos dos fármacos , Camundongos , Sistema Nervoso Entérico/efeitos dos fármacos , Regeneração Nervosa/efeitos dos fármacos
18.
Emerg Infect Dis ; 19(7): 1098-101, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23768982

RESUMO

Oral outbreaks of Chagas disease are increasingly reported in Latin America. The transitory presence of Trypanosoma cruzi parasites within contaminated foods, and the rapid consumption of those foods, precludes precise identification of outbreak origin. We report source attribution for 2 peri-urban oral outbreaks of Chagas disease in Venezuela via high resolution microsatellite typing.


Assuntos
Doença de Chagas/epidemiologia , Trypanosoma cruzi/genética , Adolescente , Adulto , Anticorpos Antiprotozoários/sangue , Doença de Chagas/sangue , Doença de Chagas/parasitologia , Doença de Chagas/transmissão , Criança , Análise por Conglomerados , Busca de Comunicante , Análise Discriminante , Surtos de Doenças , Genes de Protozoários , Humanos , Repetições de Microssatélites , Epidemiologia Molecular , Tipagem Molecular , Filogenia , Análise de Componente Principal , Trypanosoma cruzi/imunologia , Venezuela/epidemiologia
19.
J Am Pharm Assoc (2003) ; 53(6): 632-9, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24185430

RESUMO

OBJECTIVES: To qualitatively explore clinician and pharmacist attitudes toward using a Web application virtual pharmacist-clinician partnership (VPCP) to assist with comanaged care of illicit drug-using patients prescribed postexposure prophylaxis (PEP). DESIGN: Qualitative, descriptive, nonexperimental study. SETTING: New York City (NYC) from February 2011 to March 2012. PARTICIPANTS: Four pharmacists and nine clinicians. INTERVENTION: In-depth interviews. MAIN OUTCOME MEASURES: Potential impact of the VPCP on pharmacist-clinician communication and potential barriers to use of the VPCP when comanaging PEP patients among pharmacists and clinicians. RESULTS: Pharmacists and clinicians were supportive of an interactive Web application that would expand the role of pharmacists to include assistance with PEP access and patient management. Participants noted that the VPCP would facilitate communication between pharmacists and clinicians and have potential to support adherence among patients. Pharmacists and clinicians were concerned about not having time to use the VPCP and security of patient information on the site. Pharmacist and clinician concerns informed final development of the VPCP, including creation of a user-friendly interface, linkage to users' e-mail accounts for timeline notification, and attention to security. CONCLUSION: Use of Web-based technology to support communication between pharmacists and clinicians was seen as being a potentially feasible method for improving patient care, particularly in the delivery of PEP to drug users and other high-risk groups. These findings highlight the need for further study of a technology-supported partnership, particularly for comanagement of patients who face challenges with adherence.


Assuntos
Atitude do Pessoal de Saúde , Infecções por HIV/prevenção & controle , Internet , Profilaxia Pós-Exposição/métodos , Serviços Comunitários de Farmácia/organização & administração , Comportamento Cooperativo , Coleta de Dados , Atenção à Saúde , Estudos de Viabilidade , Feminino , Humanos , Comunicação Interdisciplinar , Masculino , Cidade de Nova Iorque , Profissionais de Enfermagem/organização & administração , Profissionais de Enfermagem/psicologia , Assistência ao Paciente/métodos , Assistência ao Paciente/normas , Farmacêuticos/organização & administração , Farmacêuticos/psicologia , Médicos/organização & administração , Médicos/psicologia , Papel Profissional , Qualidade da Assistência à Saúde , Transtornos Relacionados ao Uso de Substâncias/epidemiologia , Interface Usuário-Computador
20.
Pathogens ; 12(11)2023 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-38003828

RESUMO

Chronic Chagas cardiomyopathy (CCC) results from infection with the protozoan parasite Trypanosoma cruzi and is a prevalent cause of heart disease in endemic countries. We previously found that cardiac fibrosis can vary widely in C3H/HeN mice chronically infected with T. cruzi JR strain, mirroring the spectrum of heart disease in humans. In this study, we examined functional cardiac abnormalities in this host:parasite combination to determine its potential as an experimental model for CCC. We utilised electrocardiography (ECG) to monitor T. cruzi-infected mice and determine whether ECG markers could be correlated with cardiac function abnormalities. We found that the C3H/HeN:JR combination frequently displayed early onset CCC indicators, such as sinus bradycardia and right bundle branch block, as well as prolonged PQ, PR, RR, ST, and QT intervals in the acute stage. Our model exhibited high levels of cardiac inflammation and enhanced iNOS expression in the acute stage, but denervation did not appear to have a role in pathology. These results demonstrate the potential of the C3H/HeN:JR host:parasite combination as a model for CCC that could be used for screening new compounds targeted at cardiac remodelling and for examining the potential of antiparasitic drugs to prevent or alleviate CCC development and progression.

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