scholarly journals Immunity conferred by drug-cured experimental Trypanosoma cruzi infections is long-lasting and cross-strain protective

2019 ◽  
Author(s):  
Gurdip Singh Mann ◽  
Amanda F. Francisco ◽  
Shiromani Jayawardhana ◽  
Martin C. Taylor ◽  
Michael D. Lewis ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Bioluminescence Imaging ◽  
Viral Vector ◽  
Parasite Burden ◽  
Whole Body ◽  
Luciferase Reporter ◽  
Chronic Stage ◽  
Route Of Infection ◽  
Highly Sensitive

ABSTRACTBackgroundThe long term and complex nature of Chagas disease in humans has restricted studies on vaccine feasibility. Animal models also have limitations due to technical difficulties in monitoring the extremely low parasite burden that is characteristic of chronic stage infections. Advances in imaging technology offer alternative approaches that circumvent these problems. Here, we describe the use of highly sensitive whole body in vivo imaging to assess the efficacy of recombinant viral vector vaccines and benznidazole-cured infections to protect mice from challenge with Trypanosoma cruzi.Methodology/Principal FindingsMice were infected with T. cruzi strains modified to express a red-shifted luciferase reporter. Using bioluminescence imaging, we assessed the degree of immunity to re-infection conferred after benznidazole-cure. Mice infected for 14 days or more, prior to the initiation of treatment, were highly protected from challenge with both homologous and heterologous strains (>99% reduction in parasite burden). Sterile protection against homologous challenge was frequently observed. This level of protection was considerably greater than that achieved with recombinant vaccines. It was also independent of the route of infection or size of the challenge inoculum, and was long-lasting, with no significant diminution in immunity after almost a year. When the primary infection was benznidazole-treated after 4 days (before completion of the first cycle of intracellular infection), the degree of protection was much reduced, an outcome associated with a minimal T. cruzi-specific IFN-γ+ T cell response.Conclusions/SignificanceOur findings suggest that a protective Chagas disease vaccine must have the ability to eliminate parasites before they reach organs/tissues, such as the GI tract, where once established, they become largely refractory to the induced immune response.AUTHOR SUMMARYChagas disease, which is caused by the protozoan parasite Trypanosoma cruzi, is a major public health problem throughout Latin America. Attempts to develop a vaccine have been hampered by technical difficulties in monitoring the extremely low parasite burden during the life-long chronic stage of infection. To circumvent these issues, we used highly sensitive bioluminescence imaging to assess the ability of recombinant viral vector vaccines and drug-cured infections to confer protection against experimental challenge in mice. We observed that drug-cured infections were much more effective than subunit vaccines, with many instances of sterile protection. Efficacy was independent of the route of infection or size of the challenge inoculum, and was undiminished after almost a year. In addition, drug-cured infections conferred a high level of cross-strain protection. The highly sensitive imaging procedures enabled us to visualise parasite distribution in mice where sterile protection was not achieved. This suggested that to confer sterile protection, vaccines must prevent the infection of organs/tissues that act as parasite reservoirs during the chronic stage. Once established at these sites, parasites become largely refractory to vaccine-induced elimination.

scholarly journals Limited Ability of Posaconazole To Cure both Acute and Chronic Trypanosoma cruzi Infections Revealed by Highly SensitiveIn VivoImaging

2015 ◽  
Vol 59 (8) ◽  
pp. 4653-4661 ◽  
Author(s):  
Amanda Fortes Francisco ◽  
Michael D. Lewis ◽  
Shiromani Jayawardhana ◽  
Martin C. Taylor ◽  
Eric Chatelain ◽  
...  
Keyword(s):  
Clinical Trial ◽  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Imaging System ◽  
Ex Vivo ◽  
Parasite Burden ◽  
Significant Activity ◽  
Content Type ◽  
Chronic Stage

ABSTRACTThe antifungal drug posaconazole has shown significant activity againstTrypanosoma cruziin vitroand 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 bioluminescentT. cruziwere assessed byin vivoandex vivoimaging, 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 chronicT. cruziinfections. 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. Thisin vivoscreening 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.

scholarly journals Spatial metabolomics identifies localized chemical changes in heart tissue during chronic cardiac Chagas disease

2020 ◽  
Author(s):  
Danya A. Dean ◽  
Gautham ◽  
Jair L. Siqueira-Neto ◽  
James H. McKerrow ◽  
Pieter C. Dorrestein ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Parasite Burden ◽  
Heart Tissue ◽  
Blood Transfusions ◽  
Organ Transplants ◽  
Chronic Stage ◽  
Congenital Transmission ◽  
Cardiac Symptoms ◽  
The Impact

AbstractChagas disease (CD) is one of thirteen neglected tropical diseases caused by the parasite Trypanosoma cruzi. CD is a vector-borne disease transmitted by triatomines but CD can also be transmitted through blood transfusions, organ transplants and congenital transmission. While endemic to Latin America, T. cruzi infects 7-8 million people worldwide and can induce severe cardiac symptoms including apical aneurysms, thromboembolisms and arrhythmias during the chronic stage of CD. However, these cardiac clinical manifestations and CD disease pathogenesis are not fully understood. Using spatial metabolomics (chemical cartography), we sought to understand the localized impact of infection on the cardiac metabolome of mice chronically infected with two divergent T. cruzi strains. Our data showed chemical differences in localized cardiac regions upon chronic T. cruzi infection, indicating that parasite infection changes the host metabolome at select sites in chronic CD. These sites were distinct from the sites of highest parasite burden. In addition, we identified acylcarnitines and phosphocholines as discriminatory chemical families within each heart region, comparing infected and uninfected samples. Overall, our study indicated overall and positional metabolic differences common to infection with different T. cruzi strains, and identified select infection-modulated pathways. These results provide further insight into CD pathogenesis and demonstrate the advantage of a spatial perspective to understand infectious disease tropism.Author SummaryChagas disease (CD) is a tropical disease caused by the parasite Trypanosoma cruzi. CD originated in South America; however, there are now 7-8 million people infected worldwide due to population movements. CD is transmitted through a triatomine vector, organ transplants, blood transfusions and congenital transmission. It occurs in two stages, an acute stage (usually asymptomatic) and the chronic stage. Chronic stage CD presents with severe cardiac symptoms such as heart failure, localized aneurysms and cardiomyopathy. Unfortunately, what causes severe cardiac symptoms in some individuals in chronic CD is not fully understood. Therefore, we used liquid chromatography-tandem mass spectrometry to analyze the heart tissue of chronically T. cruzi-infected and uninfected mice, to understand the impact of infection on the tissue metabolome. We identified discriminatory small molecules related to T. cruzi infection. We also determined that regions with the highest parasite burden are distinct from the regions with the largest changes in overall metabolite profile; these locations of high metabolic perturbation provide a molecular mechanism to why localized cardiac symptoms occur in CD. Overall, our work gives insight to chronic cardiac CD symptom development and shapes a framework for novel treatment and biomarker development.

scholarly journals A New Experimental Model for Assessing Drug Efficacy against Trypanosoma cruzi Infection Based on Highly Sensitive In Vivo Imaging

2014 ◽  
Vol 20 (1) ◽  
pp. 36-43 ◽  
Author(s):  
Michael D. Lewis ◽  
Amanda Fortes Francisco ◽  
Martin C. Taylor ◽  
John M. Kelly
Keyword(s):  
Trypanosoma Cruzi ◽  
Experimental Model ◽  
In Vivo Imaging ◽  
Imaging System ◽  
Parasite Burden ◽  
Significant Treatment ◽  
In Vivo Models ◽  
Chronic Stage ◽  
Highly Sensitive

The protozoan Trypanosoma cruzi is the causative agent of Chagas disease, one of the world’s major neglected infections. Although development of improved antiparasitic drugs is considered a priority, there have been no significant treatment advances in the past 40 years. Factors that have limited progress include an incomplete understanding of pathogenesis, tissue tropism, and disease progression. In addition, in vivo models, which allow parasite burdens to be tracked throughout the chronic stage of infection, have been lacking. To address these issues, we have developed a highly sensitive in vivo imaging system based on bioluminescent T. cruzi, which express a red-shifted luciferase that emits light in the tissue-penetrating orange-red region of the spectrum. The exquisite sensitivity of this noninvasive murine model has been exploited to monitor parasite burden in real time throughout the chronic stage, has allowed the identification of the gastrointestinal tract as the major niche of long-term infection, and has demonstrated that chagasic heart disease can develop in the absence of locally persistent parasites. Here, we review the parameters of the imaging system and describe how this experimental model can be incorporated into drug development programs as a valuable tool for assessing efficacy against both acute and chronic T. cruzi infections.

scholarly journals 3D mapping of host-parasite-microbiome interactions reveals metabolic determinants of tissue tropism and disease tolerance in Chagas disease

2019 ◽  
Author(s):  
Ekram Hossain ◽  
Sharmily Khanam ◽  
Chaoyi Wu ◽  
Sharon Lostracco-Johnson ◽  
Diane Thomas ◽  
...  
Keyword(s):  
Chagas Disease ◽  
Large Intestine ◽  
Large Scale ◽  
Scale Effects ◽  
Parasitic Infection ◽  
Parasite Burden ◽  
Acute Stage ◽  
Disease Tolerance ◽  
Chronic Stage ◽  
Spatially Resolved

AbstractChagas disease (CD) is a parasitic infection caused by Trypanosoma cruzi protozoa. Over 8 million people worldwide are T. cruzi-positive, 20-30% of which will develop cardiomyopathy, megaoesophagus and/or megacolon. The mechanisms leading to gastrointestinal (GI) symptom development are however poorly understood. To address this issue, we systematically characterized the spatial impact of experimental T. cruzi infection on the microbiome and metabolome across the GI tract. The largest microbiota perturbations were observed in the proximal large intestine in both acute and chronic disease, with chronic-stage effects also observed in the cecum. Strikingly, metabolomic impact of acute-to-chronic stage transition differed depending on the organ, with persistent large-scale effects of infection primarily in the oesophagus and large intestine, providing a potential mechanism for GI pathology tropism in CD. Infection particularly affected acylcarnitine and lipid metabolism. Building on these observations, treatment of infected mice with carnitine-supplemented drinking water prevented acute-stage mortality with no changes in parasite burden. Overall, these results identified a new mechanism of disease tolerance in CD, with potential for the development of new therapeutic regimens. More broadly, these results highlight the potential of spatially-resolved metabolomic approaches to provide insight into disease pathogenesis, with translational applications for infectious disease drug development.

scholarly journals In Vivo Analysis of Trypanosoma cruzi Persistence Foci at Single-Cell Resolution

mBio ◽  
2020 ◽  
Vol 11 (4) ◽  
Author(s):  
Alexander I. Ward ◽  
Michael D. Lewis ◽  
Archie A. Khan ◽  
Conor J. McCann ◽  
Amanda F. Francisco ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Immune Response ◽  
Smooth Muscle ◽  
Trypanosoma Cruzi ◽  
Parasite Burden ◽  
Circular Muscle ◽  
Muscle Layer ◽  
Chronic Infections ◽  
Content Type ◽  
Chronic Stage

ABSTRACT Infections with Trypanosoma cruzi are usually lifelong despite generating a strong adaptive immune response. Identifying the sites of parasite persistence is therefore crucial to understanding how T. cruzi avoids immune-mediated destruction. However, this is a major technical challenge, because the parasite burden during chronic infections is extremely low. Here, we describe an integrated approach involving comprehensive tissue processing, ex vivo imaging, and confocal microscopy, which allowed us to visualize infected host cells in murine tissue with exquisite sensitivity. Using bioluminescence-guided tissue sampling, with a detection level of <20 parasites, we showed that in the colon, smooth muscle myocytes in the circular muscle layer are the most common infected host cell type. Typically, during chronic infections, the entire colon of a mouse contains only a few hundred parasites, often concentrated in a small number of cells each containing >200 parasites, which we term mega-nests. In contrast, during the acute stage, when the total parasite burden is considerably higher and many cells are infected, nests containing >50 parasites are rarely found. In C3H/HeN mice, but not BALB/c mice, we identified skeletal muscle as a major site of persistence during the chronic stage, with most parasites being found in large mega-nests within the muscle fibers. Finally, we report that parasites are also frequently found in the skin during chronic murine infections, often in multiple infection foci. In addition to being a site of parasite persistence, this anatomical reservoir could play an important role in insect-mediated transmission and have implications for drug development. IMPORTANCE Trypanosoma cruzi causes Chagas disease, the most important parasitic infection in Latin America. Major pathologies include severe damage to the heart and digestive tract, although symptoms do not usually appear until decades after infection. Research has been hampered by the complex nature of the disease and technical difficulties in locating the extremely low number of parasites. Here, using highly sensitive imaging technology, we reveal the sites of parasite persistence during chronic-stage infections of experimental mice at single-cell resolution. We show that parasites are frequently located in smooth muscle cells in the circular muscle layer of the colon and that skeletal muscle cells and the skin can also be important reservoirs. This information provides a framework for investigating how the parasite is able to survive as a lifelong infection, despite a vigorous immune response. It also informs drug development strategies by identifying tissue sites that must be accessed to achieve a curative outcome.

scholarly journals Highly Sensitive Bioluminescence Imaging Models for Chagas Disease Drug Discovery

Proceedings ◽  
2017 ◽  
Vol 1 (6) ◽  
pp. 676
Author(s):  
John M. Kelly ◽  
Amanda F. Francisco ◽  
Shiromani Jayawardhana ◽  
Martin C. Taylor ◽  
Michael D. Lewis
Keyword(s):  
Drug Discovery ◽  
Chagas Disease ◽  
Bioluminescence Imaging ◽  
Highly Sensitive

scholarly journals Tolerance of Benznidazole in Treatment of Chagas' Disease in Adults

2010 ◽  
Vol 54 (11) ◽  
pp. 4896-4899 ◽  
Author(s):  
María-Jesús Pinazo ◽  
José Muñoz ◽  
Elizabeth Posada ◽  
Paulo López-Chejade ◽  
Montserrat Gállego ◽  
...  
Keyword(s):  
Public Health ◽  
Side Effects ◽  
Trypanosoma Cruzi ◽  
European Country ◽  
Chagas Disease ◽  
Health Problem ◽  
Public Health Problem ◽  
Acute Stage ◽  
Chronic Stage

ABSTRACT Chagas’ disease is an emerging public health problem in areas where the disease is not endemic. Treatment with benznidazole has shown efficacy in the acute stage of the disease, but its efficacy in the chronic stage remains controversial, and unwanted side effects are more frequent and severe in adults than in children. This study describes the profile of side effects of benznidazole in a cohort of Trypanosoma cruzi-infected patients in a European country.

scholarly journals Oral Exposure to Trypanosoma cruzi Elicits a Systemic CD8+T Cell Response and Protection against Heterotopic Challenge

2011 ◽  
Vol 79 (8) ◽  
pp. 3397-3406 ◽  
Author(s):  
Matthew H. Collins ◽  
Julie M. Craft ◽  
Juan M. Bustamante ◽  
Rick L. Tarleton
Keyword(s):  
T Cell ◽  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Cell Response ◽  
Oral Route ◽  
T Cell Response ◽  
Oral Exposure ◽  
Oral Vaccination ◽  
Content Type ◽  
Route Of Infection

ABSTRACTTrypanosoma cruziinfects millions of people in Latin America and often leads to the development of Chagas disease.T. cruziinfection can be acquired at or near the bite site of the triatomine vector, butper osinfection is also a well-documented mode of transmission, as evidenced by recent microepidemics of acute Chagas disease attributed to the consumption of parasite-contaminated foods and liquids. It would also be convenient to deliver vaccines forT. cruziby the oral route, particularly live parasite vaccines intended for the immunization of reservoir hosts. For these reasons, we were interested in better understanding immunity toT. cruzifollowing oral infection or oral vaccination, knowing that the route of infection and site of antigen encounter can have substantial effects on the ensuing immune response. Here, we show that the route of infection does not alter the ability ofT. cruzito establish infection in muscle tissue nor does it impair the generation of a robust CD8+T cell response. Importantly, oral vaccination with attenuated parasites provides protection against wild-type (WT)T. cruzichallenge. These results strongly support the development of whole-organism-based vaccines targeting reservoir species as a means to alleviate the burden of Chagas disease in affected regions.

Trypanosoma cruzi Infection Prevalence and Bloodmeal Analysis in Triatomine Vectors of Chagas Disease From Rural Peridomestic Locations in Texas, 2013–2014

2016 ◽  
Vol 53 (4) ◽  
pp. 911-918 ◽  
Author(s):  
Rodion Gorchakov ◽  
Lillian P. Trosclair ◽  
Edward J. Wozniak ◽  
Patricia T. Feria ◽  
Melissa N. Garcia ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Disease Surveillance ◽  
Public Awareness ◽  
Parasite Burden ◽  
Etiologic Agent ◽  
Infection Prevalence ◽  
Transmission Cycle ◽  
High Infection ◽  
History Of

Abstract Protozoan pathogen Trypanosoma cruzi (Chagas, 1909) is the etiologic agent of Chagas disease, which affects millions of people in Latin America. Recently, the disease has been gaining attention in Texas and the southern United States. Transmission cycle of the parasite involves alternating infection between insect vectors and vertebrate hosts (including humans, wildlife, and domestic animals). To evaluate vector T. cruzi parasite burden and feeding patterns, we tested triatomine vectors from 23 central, southern, and northeastern counties of Texas. Out of the 68 submitted specimens, the majority were genetically identified as Triatoma gerstaeckeri (Stal, 1859), with a few samples of Triatoma sanguisuga (LeConte, 1855), Triatoma lecticularia (Stal, 1859), Triatoma rubida (Uhler, 1894), and Triatoma protracta woodi (Usinger, 1939). We found almost two-thirds of the submitted insects were polymerase chain reaction-positive for T. cruzi. Bloodmeal sources were determined for most of the insects, and 16 different species of mammals were identified as hosts. The most prevalent type of bloodmeal was human, with over half of these insects found to be positive for T. cruzi. High infection rate of the triatomine vectors combined with high incidence of feeding on humans highlight the importance of Chagas disease surveillance in Texas. With our previous findings of autochthonous transmission of Chagas disease, urgent measures are needed to increase public awareness, vector control in and around homes, and Chagas screening of residents who present with a history of a triatomine exposure.

scholarly journals Bioluminescent:fluorescent Trypanosoma cruzi Reporter Strains as Tools for Exploring Chagas Disease Pathogenesis and Drug Activity

2020 ◽  
Vol 26 ◽  
Author(s):  
Martin C. Taylor ◽  
Alexander I. Ward ◽  
Francisco Olmo ◽  
Amanda F. Francisco ◽  
Shiromani Jayawardhana ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Parasite Burden ◽  
New Drugs ◽  
Host Cells ◽  
Complex Nature ◽  
Disease Pathogenesis ◽  
Drug Activity ◽  
Cellular Environment

: Chagas disease results from infection with the trypanosomatid parasite Trypanosoma cruzi. Progress in developing new drugs has been hampered by the long term and complex nature of the condition and by our limited understanding of parasite biology. Technical difficulties in assessing the parasite burden during the chronic stage of infection have also proved to be a particular challenge. In this context, the development of non-invasive, highly sensitive bioluminescence imaging procedures, based on parasites that express a red-shifted luciferase, has greatly enhanced our ability to monitor infections in experimental models. Applications of this methodology have led to new insights into tissue tropism and infection dynamics, and have been a major driver in drug development. The system has been further modified by the generation of parasite reporter lines that express bioluminescent:fluorescent fusion proteins, an advance that has allowed chronic infections in mice to be examined at a cellular level. By exploiting bioluminescence to identify the rare sites of tissue infection, and fluorescence to detect T. cruzi at the level of individual host cells in histological sections, it has been possible to investigate the replication and differentiation status of parasites in vivo and to examine the cellular environment of infection foci. In combination, these data are providing a framework for the detailed dissection of disease pathogenesis and drug activity.

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