The fecal, oral, and skin microbiota of children with Chagas disease treated with benznidazole

Small molecule mediators of host-T. cruzi-environment interactions in Chagas disease

Small molecules (less than 1,500 Da) include major biological signals that mediate host-pathogen-microbiome communication. They also include key intermediates of metabolism and critical cellular building blocks. Pathogens present with unique nutritional needs that restrict pathogen colonization or promote tissue damage. In parallel, parts of host metabolism are responsive to immune signaling and regulated by immune cascades. These interactions can trigger both adaptive and maladaptive metabolic changes in the host, with microbiome-derived signals also contributing to disease progression. In turn, targeting pathogen metabolic needs or maladaptive host metabolic changes is an important strategy to develop new treatments for infectious diseases. Trypanosoma cruzi is a single-celled eukaryotic pathogen and the causative agent of Chagas disease, a neglected tropical disease associated with cardiac and intestinal dysfunction. Here, we discuss the role of small molecules during T. cruzi infection in its vector and in the mammalian host. We integrate these findings to build a theoretical interpretation of how maladaptive metabolic changes drive Chagas disease and extrapolate on how these findings can guide drug development.

PE (0:0/14:0), an endogenous metabolite of the gut microbiota, exerts protective effects against sepsis-induced intestinal injury by modulating the AHR/CYP1A1 pathway

Sepsis is known to cause damage to the intestinal mucosa, leading to bacterial translocation, and exacerbation of both local and remote organ impairments. In the present study, fecal samples were collected from both septic and healthy individuals. Analysis through 16s rRNA sequencing of the fecal microbiota revealed that sepsis disrupts the balance of the gut microbial community. Recent research has highlighted the association of lipid metabolism with disease. By analyzing the fecal metabolome, four lipid metabolites that showed significant differences between the two groups were identified: PE (O-16:0/0:0), PE (17:0/0:0), PE (0:0/14:0), and PE (12:0/20:5 (5Z, 8Z, 11Z, 14Z, 17Z)). Notably, the serum levels of PE (0:0/14:0) were higher in the healthy group. Subsequent in vitro and in vivo experiments demonstrated the protective effects of this compound against sepsis-induced intestinal barrier damage. Label-free proteomic analysis showed significant differences in the expression levels of the aryl hydrocarbon receptor (AHR), a protein implicated in sepsis pathogenesis, between the LPS-Caco-2 and LPS-Caco-2 + PE (0:0/14:0) groups. Further analysis, with the help of Discovery Studio 3.5 software and co-immunoprecipitation assays, confirmed the direct interaction between AHR and PE (0:0/14:0). In the cecal ligation and puncture (CLP) model, treatment with PE (0:0 /14:0) was found to up-regulate the expression of tight junction proteins through the AHR/Cytochrome P450, family 1, subfamily A, and polypeptide 1 (CYP1A1) pathway. This highlights the potential therapeutic use of PE (0:0/14:0) in addressing sepsis-induced intestinal barrier damage.

Localized cardiac small molecule trajectories and persistent chemical sequelae in experimental Chagas disease

Post-infectious conditions present major health burdens but remain poorly understood. In Chagas disease (CD), caused by Trypanosoma cruzi parasites, antiparasitic agents that successfully clear T. cruzi do not always improve clinical outcomes. In this study, we reveal differential small molecule trajectories between cardiac regions during chronic T. cruzi infection, matching with characteristic CD apical aneurysm sites. Incomplete, region-specific, cardiac small molecule restoration is observed in animals treated with the antiparasitic benznidazole. In contrast, superior restoration of the cardiac small molecule profile is observed for a combination treatment of reduced-dose benznidazole plus an immunotherapy, even with less parasite burden reduction. Overall, these results reveal molecular mechanisms of CD treatment based on simultaneous effects on the pathogen and on host small molecule responses, and expand our understanding of clinical treatment failure in CD. This link between infection and subsequent persistent small molecule perturbation broadens our understanding of infectious disease sequelae.

Kidney Pathology of Tropical and Nontropical Infectious Diseases in the Pediatric Population

OBJECTIVES

To review kidney pathology of tropical and nontropical infectious diseases in the pediatric population.

METHODS

We review 4 tropical and 2 nontropical infectious diseases that affect the kidneys of children in terms of their direct and indirect pathogenetic mechanism in inducing kidney damage.

RESULTS

We demonstrate clinical manifestations, pathogenesis, kidney pathology, and laboratory diagnostic methods for (1) renal cryptococcosis, which represents involvement of a pure direct pathway; (2) schistosomiasis and dengue fever as examples of dual direct and indirect pathways; and (3) congenital syphilis, visceral leishmaniasis, and Chagas disease, which represent indirect pathways.

CONCLUSIONS

Infective agents affect the kidneys of children mainly through indirect mechanisms, such as through immunological mechanisms as part of an antigenic response. A direct mechanism of kidney injury, however, is less known within the medical community simply because the direct mechanism is rarely encountered in nontropical countries. In some infectious diseases, both indirect and direct pathways are responsible in inducing 2 sets of morphologically separate kidney lesions.

Review of pharmacological options for the treatment of Chagas disease

Chagas disease (CD) is a worldwide problem, with over 8 million people infected in both rural and urban areas. CD was first described over a century ago, but only two drugs are currently available for CD treatment: benznidazole (BZN) and nifurtimox (NF). Treating CD-infected patients, especially children and women of reproductive age, is vital in order to prevent long-term sequelae, such as heart and gastrointestinal dysfunction, but this aim is still far from being accomplished. Currently, the strongest data to support benefit-risk considerations come from trials in children. Treatment response biomarkers need further development as serology is being questioned as the best method to assess treatment response. This article is a narrative review on the pharmacology of drugs for CD, particularly BZN and NF. Data on drug biopharmaceutical characteristics, safety and efficacy of both drugs are summarized from a clinical perspective. Current data on alternative compounds under evaluation for CD treatment, and new possible treatment response biomarkers are also discussed. Early diagnosis and treatment of CD, especially in paediatric patients, is vital for an effective and safe use of the available drugs (i.e. BZN and NF). New biomarkers for CD are urgently needed for the diagnosis and evaluation of treatment efficacy, and to guide efforts from academia and pharmaceutical companies to accelerate the process of new drug development.

Molecular and Clinical Aspects of Chronic Manifestations in Chagas Disease: A State-of-the-Art Review

Chronic manifestations of Chagas disease present as disabling and life-threatening conditions affecting mainly the cardiovascular and gastrointestinal systems. Although meaningful research has outlined the different molecular mechanisms underlying Trypanosoma cruzi’s infection and the host-parasite interactions that follow, prompt diagnosis and treatment remain a challenge, particularly in developing countries and also in those where the disease is considered non-endemic. This review intends to present an up-to-date review of the parasite’s life cycle, genetic diversity, virulence factors, and infective mechanisms, as well as the epidemiology, clinical presentation, diagnosis, and treatment options of the main chronic complications of Chagas disease.

The distribution and chemical coding of enteroendocrine cells in Trypanosoma cruzi-infected individuals with chagasic megacolon

Chagas disease is caused by the parasite, Trypanosoma cruzi that causes chronic cardiac and digestive dysfunction. Megacolon, an irreversible dilation of the left colon, is the main feature of the gastrointestinal form of Chagas disease. Patients have severe constipation, a consequence of enteric neuron degeneration associated with chronic inflammation. Dysmotility, infection, neuronal loss and a chronic exacerbated inflammation, all observed in Chagas disease, can affect enteroendocrine cells (EEC) expression, which in turn, could influence the inflammatory process. In this study, we investigated the distribution and chemical coding of EEC in the dilated and non-dilated portion of T. cruzi-induced megacolon and in non-infected individuals (control colon). Using immunohistochemistry, EECs were identified by applying antibodies to chromogranin A (CgA), glucagon-like peptide 1 (GLP-1), 5-hydroxytryptamine (5-HT), peptide YY (PYY) and somatostatin (SST). Greater numbers of EEC expressing GLP-1 and SST occurred in the dilated portion compared to the non-dilated portion of the same patients with Chagas disease and in control colon, but numbers of 5-HT and PYY EEC were not significantly different. However, it was noticeable that EEC in which 5-HT and PYY were co-expressed were common in control colon, but were rare in the non-dilated and absent in the dilated portion of chagasic megacolon. An increase in the number of CgA immunoreactive EEC in chagasic patients reflected the increases in EEC numbers summarised above. Our data suggests that the denervation and associated chronic inflammation are accompanied by changes in the number and coding of EEC that could contribute to disorders of motility and defence in the chagasic megacolon.

Targeting the Gut Microbiota in Chagas Disease: What Do We Know so Far?

Chagas disease (CD) is a tropical and still neglected disease caused by Trypanosoma cruzi that affects >8 million of people worldwide. Although limited, emerging data suggest that gut microbiota dysfunction may be a new mechanism underlying CD pathogenesis. T. cruzi infection leads to changes in the gut microbiota composition of vector insects, mice, and humans. Alterations in insect and mice microbiota due to T. cruzi have been associated with a decreased immune response against the parasite, influencing the establishment and progression of infection. Further, changes in the gut microbiota are linked with inflammatory and neuropsychiatric disorders, comorbid conditions in CD. Therefore, this review article critically analyses the current data on CD and the gut microbiota of insects, mice, and humans and discusses its importance for CD pathogenesis. An enhanced understanding of host microbiota will be critical for the development of alternative therapeutic approaches to target CD, such as gut microbiota-directed interventions.

Shared neuroimmune and oxidative pathways underpinning Chagas disease and major depressive disorder

The cellular and molecular basis to understand the relationship between Chagas disease (CD), a infection caused by Trypanosoma cruzi, and depression, a common psychiatric comorbidity in CD patients, is largely unknown. Clinical studies show an association between CD and depression and preclinical evidence suggests that depressive-like behaviors in T. cruzi infected mice are due, at least partially, to immune dysregulation. However, mechanistic studies regarding this issue are still lacking. Herein, we present and discuss the state of art of data on CD and depression, and revise the mechanisms that may explain the development of depression in CD. We also discuss how the knowledge generated by current and future data may contribute to the discovery of new mechanisms underlying depressive symptoms associated with CD and, hence, to the identification of new therapeutic targets, which ultimately may change the way we see and treat CD and its psychiatric comorbidities.

NOD2 receptor is crucial for protecting against the digestive form of Chagas disease

Digestive and cardiodigestive forms of Chagas’ disease are observed in 2% to 27% of the patients, depending on their geographic location, Trypanosoma cruzi strain and immunopathological responses. The aim of this work was to evaluate the role of NOD2 innate immune receptor in the pathogenesis of the digestive system in Chagas’ disease. Patients with digestive form of the disease showed lower mRNA expression of NOD2, higher expression of RIP2 and α-defensin 6, compared to indeterminate form, detected by Real-time PCR in peripheral blood mononuclear cells. In addition, there was a negative correlation between the expression of NOD2 and the degree of dilation of the esophagus, sigmoid and rectum in those patients. The infection of NOD2^-/- mice with T. cruzi strain isolated from the digestive patient induced a decrease in intestinal motility. Histopathological analysis of the colon and jejunum of NOD2^-/- and wild type C57BL/6 animals revealed discrete inflammatory foci during the acute phase of infection. Interestingly, during the chronic phase of the infection there was inflammation and hypertrophy of the longitudinal and circular muscular layer more pronounced in the colon and jejunum from NOD2^-/- animals, when compared to wild type C57BL/6 mice. Together, our results suggest that NOD2 plays a protective role against the development of digestive form of Chagas’ disease.

Chagas disease is caused by the protozoan Trypanosoma cruzi, during the chronic phase of infection 2–27% of patients develop digestive form of the disease (megaesophagus and megacolon) that contributes to patient morbidity and mortality, generating costs for public health services, and especially affecting significantly the life quality of the patients. Although is known that many factors inherent of the parasite (tropism, genetics, virulence and antigenicity), host (age, gender, nutritional status, genetics and immune response) and geographical distribution may influence the development of the different clinical forms of Chagas disease, the exact mechanism that leads to megacolon and megaesophagus development are unknown. Here we showed that patients with digestive form of Chagas’ disease do not express the innate immune receptor NOD2. By isolating a parasite from a digestive patient and infecting NOD2-deficient mice we observed a reduced intestinal motility, chronic development of colon and jejunum wall thickness associated with increased inflammatory mediators in the organ, when compared to wild type animals. Our results indicate that the NOD2 receptor protects against the development of the digestive form of Chagas disease and could be used as a biomarker for the development of gastrointestinal changes during T. cruzi infection in patients.

Gut Dysbiosis in Chagas Disease. A Possible Link to the Pathogenesis

Chagas disease is caused by the flagellate protozoan Trypanosoma cruzi. Cardiomyopathy and damage to gastrointestinal tissue are the main disease manifestations. There are data suggesting that the immune response to T. cruzi depends on the intestinal microbiota. We hypothesized that Chagas disease is associated with an altered gut microbiome and that these changes are related to the disease phenotype. The stool microbiome from 104 individuals, 73 with Chagas disease (30 with the cardiac, 11 with the digestive, and 32 with the indeterminate form), and 31 healthy controls was characterized using 16S rRNA amplification and sequencing. The QIIME (Quantitative Insights Into Microbial Ecology) platform was used to analyze the data. Alpha and beta diversity indexes did not indicate differences between the groups. However, the relative abundance of Verrucomicrobia, represented primarily by the genus Akkermansia, was significantly lower in the Chagas disease groups, especially the cardiac group, compared to the controls. Furthermore, differences in the relative abundances of Alistipes, Bilophila, and Dialister were observed between the groups. We conclude that T. cruzi infection results in changes in the gut microbiome that may play a role in the myocardial and intestinal inflammation seen in Chagas disease.

Mapping of host-parasite-microbiome interactions reveals metabolic determinants of tropism and tolerance in Chagas disease

Chagas disease (CD) is a parasitic disease caused by Trypanosoma cruzi protozoa, presenting with cardiomyopathy, megaesophagus, and/or megacolon. To determine the mechanisms of gastrointestinal (GI) CD tissue tropism, we systematically characterized the spatial localization of infection-induced metabolic and microbiome alterations, in a mouse model of CD. Notably, the impact of the transition between acute and persistent infection differed between tissue sites, with sustained large-scale effects of infection in the esophagus and large intestine, providing a potential mechanism for the tropism of CD within the GI tract. Infection affected acylcarnitine metabolism; carnitine supplementation prevented acute-stage CD mortality without affecting parasite burden by mitigating infection-induced metabolic disturbances and reducing cardiac strain. Overall, results identified a previously-unknown mechanism of disease tolerance in CD, with potential for new therapeutic regimen development. More broadly, results highlight the potential of spatially resolved metabolomics to provide insight into disease pathogenesis and infectious disease drug development.