Treatment Of Chronic Chagas Disease Research Articles

B-Cell Responses in Chronic Chagas Disease: Waning of Trypanosoma cruzi-Specific Antibody-Secreting Cells Following Successful Etiological Treatment.

A drawback in the treatment of chronic Chagas disease (American trypanosomiasis) is the long time required to achieve complete loss of serological reactivity, the standard for determining treatment efficacy. Antibody-secreting cells and memory B cells specific for Trypanosoma cruzi and their degree of differentiation were evaluated in adult and pediatric study participants with chronic Chagas disease before and after etiological treatment. T. cruzi-specific antibody-secreting cells disappeared from the circulation in benznidazole or nifurtimox-treated participants with declining parasite-specific antibody levels after treatment, whereas B cells in most participants with unaltered antibody levels were low before treatment and did not change after treatment. The timing of the decay in parasite-specific antibody-secreting B cells was similar to that in parasite-specific antibodies, as measured by a Luminex-based assay, but preceded the decay in antibody levels detected by conventional serology. The phenotype of total B cells returned to a noninfection profile after successful treatment. T. cruzi-specific antibodies in the circulation of chronically T. cruzi-infected study participants likely derive from both antigen-driven plasmablasts, which disappear after successful treatment, and long-lived plasma cells, which persist and account for the low frequency and long course to complete seronegative conversion in successfully treated participants.

Genetic polymorphism of Trypanosoma cruzi bloodstream populations in adult chronic indeterminate Chagas disease patients from the E1224 clinical trial.

The role that the genetic diversity of natural Trypanosoma cruzi populations plays in response to trypanocidal treatment of chronic Chagas disease (CD) patients remains to be understood. We analysed the genetic polymorphisms of parasite bloodstream populations infecting chronic CD patients enrolled in the E1224 clinical trial. A total of 506 baseline and post-treatment follow-up samples from 188 patients were analysed. T. cruzi satellite DNA (satDNA) was amplified and sequenced using cruzi1/cruzi2 primers, and samples with TcI/III, TcII, TcIV or hybrid satDNA sequences were identified. Minicircle signatures were obtained after kinetoplast DNA amplification using 121/122 primers and restriction enzyme digestion. Genetic distances between baseline and post-treatment minicircle signatures were estimated using the Jaccard coefficient. At baseline, 74.3% TcII, 17.9% hybrid and 7.8% TcI/III satDNA sequences were found, whereas at the end of follow-up the distribution was 55.2% TcII, 35.2% hybrid and 9.5% TcI/III. The placebo arm was the treatment group with the highest variation of satDNA sequences between baseline and post-treatment follow-up. Genetic distances between baseline and post-treatment minicircle signatures were similar among all treatment arms. No association between minicircle signature variability and satDNA type distribution was found. Genetic variability of T. cruzi bloodstream populations during post-treatment follow-up did not differ from that observed during chronic infection in the absence of treatment, suggesting that there were no selection events of E1224-resistant parasite populations. This is the first report documenting the genetic polymorphism of natural T. cruzi populations in chronic patients in the context of clinical trials with trypanocidal drugs.

Benznidazole: Hero or villain of cellular immune response in chronic Chagas disease patients?

Although the treatment of chronic Chagas disease (CCD) patients with Benznidazole (Bz) is still controversial, its use may prevent or delay the progression of the disease to the most severe forms. One of the main factors that can influence the effectiveness of the treatment is the possible cooperation between drug effect and the host immune response. Herein, we evaluated the immune response of peripheral blood mononuclear cells (PBMCs) infected with Trypanosoma cruzi and submitted to Bz treatment. Blood samples of CCD patients (n = 7) and non-infected individuals (n = 6) were drawn to obtain PBMCs. After cell culture, the supernatants were harvested and stored, and the cell analyzed by flow cytometer. The results showed that Bz positively regulated the molecular process of cell activation (CD80) and antigen presentation (HLA-DR), increased phagocytosis receptor and macrophage activation (CD64), and did not induce an exacerbated immune response. In conclusion, these results highlight the relevance of using Bz that, despite not being a true hero, it is also not a villain, as it presents a wide range of pharmacological/immunological response interactions, important for the immune balance in the clinical progression of CCD.

Molecular dissection of Chagas induced cardiomyopathy reveals central disease associated and druggable signaling pathways.

Chagas disease, the clinical presentation of T. cruzi infection, is a major human health concern. While the acute phase of Chagas disease is typically asymptomatic and self-resolving, chronically infected individuals suffer numerous sequelae later in life. Cardiomyopathies in particular are the most severe consequence of chronic Chagas disease and cannot be reversed solely by parasite load reduction. To prioritize new therapeutic targets, we unbiasedly interrogated the host signaling events in heart tissues isolated from a Chagas disease mouse model using quantitative, multiplexed proteomics. We defined the host response to infection at both the proteome and phospho-proteome levels. The proteome showed an increase in the immune response and a strong repression of several mitochondrial proteins. Complementing the proteome studies, the phospho-proteomic survey found an abundance of phospho-site alterations in plasma membrane and cytoskeletal proteins. Bioinformatic analysis of kinase activity provided substantial evidence for the activation of NDRG2 and JNK/p38 kinases during Chagas disease. A significant activation of DYRK2 and AMPKA2 and the inhibition of casein family kinases were also predicted. We concluded our analyses by linking the diseased heart proteome profile to known therapeutic interventions, uncovering a potential to target mitochondrial proteins, secreted immune effectors and core kinases for the treatment of chronic Chagas disease. Together, this study provides molecular insight into host proteome and phospho-proteome responses to T. cruzi infection in the heart for the first time, highlighting pathways that can be further validated for functional contributions to disease and suitability as drug targets.

Quantification of Immunoglobulin G against Trypanosoma cruzi in Individuals with Chronic Chagas Disease Treated with Nifurtimox and Evaluated in Prolonged Follow-Up.

In the indeterminate chronic period of Chagas disease (ChD) the treatment has not been conclusive, because the serological negativization requires many years. This study aims to evaluate the efficacy of nifurtimox (NF) in the treatment of chronic ChD in prolonged follow-up by serological techniques of indirect immunofluorescence assay (IFA) and enzyme-linked immunosorbent assay (ELISA) IgG comparing 2 groups of patients, treated and non treated. Mann-Whitney test was performed for ELISA and IFA, with significant difference between the groups (P<0.05). IgG levels were lower in individuals treated compared with untreated patients, indicating chemotherapeutic efficacy in prolonged follow-up.

Safety Profile of Benznidazole in the Treatment of Chronic Chagas Disease: Experience of a Referral Centre and Systematic Literature Review with Meta-Analysis.

Benznidazole is the preferred drug for treatment of Chagas disease. However, it is toxic and of limited value in chronic infection. We aimed to estimate the rates of and factors related to adverse reactions (ARs) to benznidazole and treatment discontinuations (TDs). A meta-analysis was performed using an electronic search of the published literature with no language restrictions until June 2017. Prospective studies were included of chronically infected patients in which at least one treatment arm included benznidazole. Data were added from a prospective cohort of patients with Chagas disease at our centre (January 2007-June 2017). Weighted rates of ARs and TDs were estimated, and potentially related factors were analysed. Some 413 studies were found, from which we chose 42 (nine clinical trials and 33 observational studies, including ours), comprising data for 7822 patients. The weighted rate of ARs to benznidazole was 44.1% (95% confidence interval [CI] 37.2-51.2). ARs were more frequent in adults than in children (51.6 vs. 24.5%), with the most common being skin reactions (34%), gastrointestinal complaints (12.6%) and neurological symptoms (11.5%). Grade 4 ARs were recorded in 3% of cases. The weighted rate of TDs was 11.4% (95% CI 8.5-14.5); TDs were more frequent in adults than in children (14.2 vs. 3.8%). In our cohort, only female sex was related to an increased rate of ARs but not to TDs. Benznidazole had a poor tolerability profile, with a high incidence of TDs, especially in adult patients and women. Optimised dosing schedules and/or new drugs are urgently needed.

Granulocyte-Colony Stimulating Factor-Overexpressing Mesenchymal Stem Cells Exhibit Enhanced Immunomodulatory Actions Through the Recruitment of Suppressor Cells in Experimental Chagas Disease Cardiomyopathy.

Genetic modification of mesenchymal stem cells (MSCs) is a promising strategy to improve their therapeutic effects. Granulocyte-colony stimulating factor (G-CSF) is a growth factor widely used in the clinical practice with known regenerative and immunomodulatory actions, including the mobilization of regulatory T cells (Tregs) and myeloid-derived suppressor cells (MDSCs). Here we evaluated the therapeutic potential of MSCs overexpressing G-CSF (MSC_G-CSF) in a model of inflammatory cardiomyopathy due to chronic Chagas disease. C57BL/6 mice were treated with wild-type MSCs, MSC_G-CSF, or vehicle (saline) 6 months after infection with Trypanosoma cruzi. Transplantation of MSC_G-CSF caused an increase in the number of circulating leukocytes compared to wild-type MSCs. Moreover, G-CSF overexpression caused an increase in migration capacity of MSCs to the hearts of infected mice. Transplantation of either MSCs or MSC_G-CSF improved exercise capacity, when compared to saline-treated chagasic mice. MSC_G-CSF mice, however, were more potent than MSCs in reducing the number of infiltrating leukocytes and fibrosis in the heart. Similarly, MSC_G-CSF-treated mice presented significantly lower levels of inflammatory mediators, such as IFNγ, TNFα, and Tbet, with increased IL-10 production. A marked increase in the percentage of Tregs and MDSCs in the hearts of infected mice was seen after administration of MSC_G-CSF, but not MSCs. Moreover, Tregs were positive for IL-10 in the hearts of T. cruzi-infected mice. In vitro analysis showed that recombinant hG-CSF and conditioned medium of MSC_G-CSF, but not wild-type MSCs, induce chemoattraction of MDSCs in a transwell assay. Finally, MDSCs purified from hearts of MSC_G-CSF transplanted mice inhibited the proliferation of activated splenocytes in a co-culture assay. Our results demonstrate that G-CSF overexpression by MSCs potentiates their immunomodulatory effects in our model of Chagas disease and suggest that mobilization of suppressor cell populations such as Tregs and MDSCs as a promising strategy for the treatment of chronic Chagas disease. Finally, our results reinforce the therapeutic potential of genetic modification of MSCs, aiming at increasing their paracrine actions.

The long road towards a safe and effective treatment of chronic Chagas disease

The long road towards a safe and effective treatment of chronic Chagas disease

USO DE LA REACCIÓN EN CADENA DE LA POLIMERASA PARA EL CONTROL TERAPÉUTICO DE LA INFECCIÓN CRÓNICA POR Trypanosoma cruzi

Current norms for the etiological treatment of chronic Chagas disease, recommended by WHOor currently in force for Argentina and Brazil, advise the control of therapeutic efficacy usingconventional serological and parasitological tests. However, serology usually remains positive 10 ormore years after treatment and parasitological tests are insensitive in the chronic stage. PolymeraseChain Reaction (PCR) is more sensitive than parasitological tests and could provide earlier evidenceof therapeutic failure. We offered benznidazole treatment (5 mg/kg/day, 60 days) to 138 patients(age=16 to 35 years old), chronically infected with Trypanosoma cruzi. Therapeutic efficacy waschecked with periodic PCR, haemoculture and conventional serology in two groups of patients: One(TG) accepting and complying with treatment and the other (NTG) rejecting it. Before benznidazoleadministration, PCR displayed a diagnostic sensitivity of 41.3% (57/138) and haemoculture 7.2%(10/138). Sixty months after treatment, TG displayed a cumulated PCR positivity of 28.1% (16/57)and NTG 54.1% (20/37; p=0.0166). Even though the sensitivity of PCR is limited, repeated negativeresults of a standardized method may reveal lower parasitaemia or probable cure, in 71.9% of treatedpatients, to be confirmed with serological follow up.

Towards a paradigm shift in the treatment of chronic Chagas disease.

Treatment for Chagas disease with currently available medications is recommended universally only for acute cases (all ages) and for children up to 14 years old. The World Health Organization, however, also recommends specific antiparasite treatment for all chronic-phase Trypanosoma cruzi-infected individuals, even though in current medical practice this remains controversial, and most physicians only prescribe palliative treatment for adult Chagas patients with dilated cardiomyopathy. The present opinion, prepared by members of the NHEPACHA network (Nuevas Herramientas para el Diagnóstico y la Evaluación del Paciente con Enfermedad de Chagas/New Tools for the Diagnosis and Evaluation of Chagas Disease Patients), reviews the paradigm shift based on clinical and immunological evidence and argues in favor of antiparasitic treatment for all chronic patients. We review the tools needed to monitor therapeutic efficacy and the potential criteria for evaluation of treatment efficacy beyond parasitological cure. Etiological treatment should now be mandatory for all adult chronic Chagas disease patients.

Experiencia terapéutica en un centro para la enfermedad de Chagas

American Trypanosomiasis or Chagas Disease is a major public health problem, endemic in the American continent since prehistoric times. Its natural course is towards chronicity in the immunocompetent host, often leading to severe cardiopathy or bowel involvement. Pharmacologic therapy is restricted to two drugs and only one of them is currently available in Chile. Both have poor effectiveness in the chronic stages of the disease and cause frequent adverse reactions. Many physicians avoid their use, despite published evidences about the usefulness. We herein report the experience of our Center in the treatment of Chronic Chagas Disease in adults using the drug nifurtimox, emphasizing its degree of acceptability and its secondary effects.

Evaluation of Nifurtimox Treatment of Chronic Chagas Disease by Means of Several Parasitological Methods

Currently, evaluation of drug efficacy for Chagas disease remains a controversial issue with no consensus. In this work, we evaluated the parasitological efficacy of Nifurtimox treatment in 21 women with chronic Chagas disease from an area of endemicity in Chile who were treated according to current protocols. Under pre- and posttherapy conditions, blood (B) samples and xenodiagnosis (XD) samples from these patients were subjected to analysis by real-time PCR targeting the nuclear satellite DNA of Trypanosoma cruzi (Sat DNA PCR-B, Sat DNA PCR-XD) and by PCR targeting the minicircle of kinetoplast DNA of T. cruzi (kDNA PCR-B, kDNA PCR-XD) and by T. cruzi genotyping using hybridization minicircle tests in blood and fecal samples of Triatoma infestans feed by XD. In pretherapy, kDNA PCR-B and kDNA PCR-XD detected T. cruzi in 12 (57%) and 18 (86%) cases, respectively, whereas Sat DNA quantitative PCR-B (qPCR-B) and Sat DNA qPCR-XD were positive in 18 cases (86%) each. Regarding T. cruzi genotype analysis, it was possible to observe in pretherapy the combination of TcI, TcII, and TcV lineages, including mixtures of T. cruzi strains in most of the cases. At 13 months posttherapy, T. cruzi DNA was detectable in 6 cases (29.6%) and 4 cases (19.1%) by means of Sat DNA PCR-XD and kDNA PCR-XD, respectively, indicating treatment failure with recovery of live parasites refractory to chemotherapy. In 3 cases, it was possible to identify persistence of the baseline genotypes. The remaining 15 baseline PCR-positive cases gave negative results by all molecular and parasitological methods at 13 months posttreatment, suggesting parasite response. Within this follow-up period, kDNA PCR-XD and Sat DNA qPCR-XD proved to be more sensitive tools for the parasitological evaluation of the efficacy of Nifurtimox treatment than the corresponding PCR methods performed directly from blood samples.

Use of clomipramine as chemotherapy of the chronic phase of Chagas disease

Chagas infection is a major endemic disease affecting Latin American countries. The persistence of Trypanosoma cruzi generates a chronic inflammatory reactivity that induces an immune response directed to the host's tissues. The effectiveness of the treatment in the chronic phase is still unsatisfactory due, amongst other reasons, to the collateral effects of the drugs used. We investigated the effect of clomipramine, a tricyclic antidepressant that, when used as a treatment of T. cruzi-chronically infected mice, inhibits trypanothione reductase, an exclusive and vital enzyme of T. cruzi. Clomipramine improved survival (P<0.05) by diminishing the parasite intensity as demonstrated by PCR studies in the heart and skeletal muscle, and significantly prevented the evolution to fibrosis of the inflammatory infiltrates. Clomipramine could be a good candidate for the treatment of chronic Chagas disease.

Would selenium supplementation aid in therapy for Chagas Disease?

Chagas disease, a neglected tropical disease discovered over 100 years ago, is caused by the intracellular parasite Trypanosoma cruzi and is most frequently associated with chronic cardiomyopathy and digestive disorders. Initial invasion of cells is followed by progressive inflammatory destruction of heart, muscles, nerves, and gastrointestinal (GI) tract tissue. Approximately 30% of patients progress to a chronic cardiomyopathy associated with increased morbidity and mortality. Seven to 10% of patients develop megasyndromes involving the GI tract, in particular, the esophagus and the colon. Results from several studies suggest that selenium (Se) deficiency could be an important factor in the pathogenesis of Chagas disease. In this opinion article, Se supplementation is proposed as an adjuvant therapy for treatment of chronic Chagas disease.

A new approach for potential drug target discovery through in silico metabolic pathway analysis using Trypanosoma cruzi genome information

The current drug options for the treatment of chronic Chagas disease have not been sufficient and high hopes have been placed on the use of genomic data from the human parasite Trypanosoma cruzi to identify new drug targets and develop appropriate treatments for both acute and chronic Chagas disease. However, the lack of a complete assembly of the genomic sequence and the presence of many predicted proteins with unknown or unsure functions has hampered our complete view of the parasite's metabolic pathways. Moreover, pinpointing new drug targets has proven to be more complex than anticipated and has revealed large holes in our understanding of metabolic pathways and their integrated regulation, not only for this parasite, but for many other similar pathogens. Using an in silicocomparative study on pathway annotation and searching for analogous and specific enzymes, we have been able to predict a considerable number of additional enzymatic functions in T. cruzi. Here we focus on the energetic pathways, such as glycolysis, the pentose phosphate shunt, the Krebs cycle and lipid metabolism. We point out many enzymes that are analogous to those of the human host, which could be potential new therapeutic targets.

Back to the future in Chagas disease: from animal models to patient cohort studies, progress in immunopathogenesis research

Despite the wealth of information generated by trans-disciplinary research in Chagas disease, knowledge about its multifaceted pathogenesis is still fragmented. Here we review the body of experimental studies in animal models supporting the concept that persistent infection by Trypanosoma cruzi is crucial for the development of chronic myocarditis. Complementing this review, we will make an effort to reconcile seemingly contradictory results concerning the immune profiles of chronic patients from Argentina and Brazil. Finally, we will review the results of molecular studies suggesting that parasite-induced inflammation and tissue damage is, at least in part, mediated by the activities of trans-sialidase, mucin-linked lipid anchors (TLR2 ligand) and cruzipain (a kinin-releasing cysteine protease). One hundred years after the discovery of Chagas disease, it is reassuring that basic and clinical research tends to converge, raising new perspectives for the treatment of chronic Chagas disease.

Etiological treatment of chronic Chagas disease: neglected ‘evidence’ by evidence-based medicine

No randomized clinical trials regarding the etiological treatment of chronic Chagas disease can be found in the medical literature. However, other ‘evidence’ sustaining the use of anti-Trypanosoma cruzi drugs for adult individuals with Chagas disease will be analyzed along with the limitations in evaluating the treatment efficacy. Today, the hypothesis of T. cruzi persistence in the target organs giving rise to the chronic inflammatory response is sustained. In addition, several experimental, pathological, nonrandomized clinical studies and studies based on the response or serological evolution (besides the clinical experience) demonstrate the role of T. cruzi in the pathogenesis of the chronic stage and the efficacy of etiological treatment to reduce the titers of antibodies and the progression of chronic Chagas heart disease. All of this supports the recommendation of treatment for every patient diagnosed with Chagas disease. The interpretation of this sum of evidence is not considered from the perspective of evidence-based medicine.

Treatment of Experimental Chronic Chagas Disease with Trifluralin

We tested trifluralin against Trypanosoma cruzi in a model of chronic Chagas disease in mice. CF1 mice (n=148) were intraperitoneally infected with 10(5) trypomastigotes of T. cruzi, H510C8C3 clone. One hundred mice were partially treated with benznidazole. Mortality was 100% at day 41 in the control group (n=48). At day 90 of the chronic disease (74% survival) mice were divided into three groups and treated orally with trifluralin (50 mg/kg/day, n=26), benznidazole (50 mg/kg/day, n=25) and vehicle (peanut oil; control group, n=23) for 60 days. Electrocardiography (under pentobarbital anaesthesia, 30 mg/kg/dose), serologic immunofluorescence and microstrout were performed at the beginning and at the end of the treatment. Mice were sacrificed at day 10 after treatment; cardiac tissue was studied histopathologically and polymerase chain reaction (PCR) was performed. Spontaneous mortality was 30.43%, 3.85% and 4% in the control, trifluralin and benznidazole groups, respectively (significant survival, P=0.03). Microstrouts were negative in all three groups. Negative immunofluorescence titers were 0%, 16% (P=0.05) and 29% (P<0.02) in the control, trifluralin and benznidazole groups, respectively. The prevailing electrocardiographic disorder was prolongation of the PR interval in the control group, which was not significantly altered in trifluralin- and benznidazole-treated mice, suggesting that trifluralin and benznidazole improve or even stop the damage caused by the disease on the conduction system. Trifluralin- and benznidazole-treated animals showed similar histologic patterns of myocarditis. PCR results were negative for benznidazole and trifluralin (100% and 70.8%, respectively). These results show the therapeutic potential of trifluralin in the treatment of chronic Chagas disease.