Progression of Baseline Electrocardiogram Abnormalities in Chagas Patients Undergoing Antitrypanosomal Treatment

Tackling the challenges of human Chagas disease: A comprehensive review of treatment strategies in the chronic phase and emerging therapeutic approaches

Chagas disease (CD), caused by the flagellated protozoan Trypanosoma cruzi (T. cruzi), affects approximately 7 million people worldwide and is endemic in Latin America, especially among socioeconomically disadvantaged populations. Since the 1960s, only two drugs have been commercially available for treating this illness: nifurtimox (NFX) and benznidazole (BZN). Although these drugs are effective in the acute phase (AP) of the disease, in which parasitemia is usually high, their cure rates in the chronic phase (CP) are low and often associated with several side effects. The CP is characterized by a subpatent parasitaemia and absence of clinical symptoms in the great majority of infected individuals. However, at least 30 % of the individuals will develop potentially lethal symptomatic forms, including cardiac and digestive manifestations. For such reason, in the CP the treatment is usually symptomatic and typically focuses on managing complications such as arrhythmias, heart failure, or digestive problems. Therefore, the need for new drugs or therapeutic approaches using BZN or NFX is extremely urgent. This review presents the main clinical trials, especially in the CP, which involve BZN and NFX in different treatment regimens. Additionally, other therapies using combinations of these drugs with other substances such as allopurinol, itraconazole, ravuconazole, ketoconazole, posaconazole and amiodarone are also reported. The importance of early diagnosis, especially in pediatric patients, is also discussed, emphasizing the need to identify the disease in its early stages to improve the chances of successful treatment.

Nifurtimox for Treatment of Chagas Disease in Pediatric Patients: the Challenges of Applying Pharmacokinetic-Pharmacodynamic Principles to Dose Finding

The antiparasitic drug nifurtimox was approved in the USA in 2020 for the treatment of patients with Chagas disease aged less than 18 years and weighing at least 2.5 kg, based on outcomes from the phase 3 CHICO study. Accordingly, pediatric patients with Chagas disease take nifurtimox thrice daily with food at one of two body weight–adjusted dose ranges. We investigated possible relationships between pharmacokinetic (PK) data, and pharmacodynamic efficacy and safety data collected in an analysis population of 111 participants in CHICO, using a published population PK model to estimate nifurtimox exposure at the patient level. Pediatric exposure to nifurtimox was benchmarked against levels of nifurtimox exposure known to be effective in adults with Chagas disease. Given the complex dosing regimen for nifurtimox, we also modeled nifurtimox exposure associated with simpler dosing strategies. We found no relationship between exposure to nifurtimox and efficacy measures (e.g., serological response to treatment), or between exposure and safety outcomes (including typical adverse events, e.g., headache, decreased appetite, nausea/vomiting). The analysis population appeared to represent the overall CHICO population based on the similarity of their baseline characteristics and the profiles of adverse events in the two groups. Modeled exposure based on the dosing regimen in CHICO was within the reference range derived from phase 1 data in adults. The relationship between nifurtimox exposure and cure is complex; a simplified pediatric dosing regimen is unlikely to be beneficial.

Graphical abstract

Aspirin-triggered resolvin D1 reduces parasitic cardiac load by decreasing inflammation in a murine model of early chronic Chagas disease

Background

Chagas disease, caused by the protozoan Trypanosoma cruzi, is endemic in Latin America and is widely distributed worldwide because of migration. In 30% of cases, after years of infection and in the absence of treatment, the disease progresses from an acute asymptomatic phase to a chronic inflammatory cardiomyopathy, leading to heart failure and death. An inadequate balance in the inflammatory response is involved in the progression of chronic Chagas cardiomyopathy. Current therapeutic strategies cannot prevent or reverse the heart damage caused by the parasite. Aspirin-triggered resolvin D1 (AT-RvD1) is a pro-resolving mediator of inflammation that acts through N-formyl peptide receptor 2 (FPR2). AT-RvD1 participates in the modification of cytokine production, inhibition of leukocyte recruitment and efferocytosis, macrophage switching to a nonphlogistic phenotype, and the promotion of healing, thus restoring organ function. In the present study, AT-RvD1 is proposed as a potential therapeutic agent to regulate the pro-inflammatory state during the early chronic phase of Chagas disease.

Methodology/Principal findings

C57BL/6 wild-type and FPR2 knock-out mice chronically infected with T. cruzi were treated for 20 days with 5 μg/kg/day AT-RvD1, 30 mg/kg/day benznidazole, or the combination of 5 μg/kg/day AT-RvD1 and 5 mg/kg/day benznidazole. At the end of treatment, changes in immune response, cardiac tissue damage, and parasite load were evaluated. The administration of AT-RvD1 in the early chronic phase of T. cruzi infection regulated the inflammatory response both at the systemic level and in the cardiac tissue, and it reduced cellular infiltrates, cardiomyocyte hypertrophy, fibrosis, and the parasite load in the heart tissue.

Conclusions/Significance

AT-RvD1 was shown to be an attractive therapeutic due to its regulatory effect on the inflammatory response at the cardiac level and its ability to reduce the parasite load during early chronic T. cruzi infection, thereby preventing the chronic cardiac damage induced by the parasite.

Chagas disease is prevalent in Latin America and is widely distributed worldwide due to migration. In 30% of patients, if the parasite is left untreated, the disease may progress from an acute symptomless phase to chronic myocardial inflammation, which can cause heart failure and death, years after the infection. Imbalances in the inflammatory response are related to this progression. Current treatments cannot prevent or reverse the cardiac damage inflicted by the parasite. Aspirin-triggered resolvin D1, also named AT-RvD1, can modify cellular and humoral inflammatory responses leading to the resolution of inflammation, thus promoting healing and restoring organ function. In this study, AT-RvD1, in an N-formyl peptide receptor 2 (FPR2)-dependent manner, was shown to regulate local and systemic inflammation and decrease cellular infiltration in the heart tissue of mice chronically infected with the parasite and reduce cardiac hypertrophy and fibrosis in the early stages of the chronic phase of the disease. Importantly, AT-RvD1 was able to decrease parasite load in the infected hearts. Thus, this research indicates that At-RvD1 treatment is a potential therapeutic strategy that offers an improvement on current drug therapies.

Clinical, electrocardiographic and echocardiographic evolution of chronic Chagas disease treated with nifurtimox on prolonged follow-up in Chile: observational study

OBJECTIVES

This study aimed to describe the electrocardiographic and echocardiographic status of chronic Chagas disease (cChD) patients treated with nifurtimox.

METHODS

An observational study was performed in 146 cChD patients followed over a mean of 7.9 years.

RESULTS

Of the 146 patients, 41 (28.1%) with normal electrocardiogram (ECG) at baseline maintained this condition, 34 (23.3%) with altered ECG at baseline normalised the alterations, and 46 (31.5%) with ECG abnormalities at baseline maintained this condition [23 (15.8%) with small alterations]. Finally, 25 cases (17.1%) in indeterminate phase altered the ECG. Differences before and after follow-up (P < 0.001) were found. The percentage of beneficial treatment was different than expected by chance (Z = 4.8; P < 0.001) and the annual percentage of cases that developed ECG alterations was lower than that of a historical cohort of untreated patients (P < 0.001). An echocardiogram was performed in 68 patients with baseline ECG alterations. The ejection fraction (EF) was normal in 57 (83.8%) and abnormal in 11 (16.2%). In 38 patients with ECG abnormalities that did not progress after treatment, EF and segmental motility (SM) were normal in 31 (81.6%) and 26 (68.4%), respectively. In 17 patients with ECG abnormalities, EF and SM were normal in 15 (88.2%) and 14 (82.4%) cases, respectively.

CONCLUSION

Less progression to cardiomyopathy compared with a historical untreated cohort as well as the EF/SM results in patients with abnormal ECG that did not progress and in indeterminate cChD that altered the ECG suggests a beneficial effect of nifurtimox.

A Rapid Review on the Efficacy and Safety of Pharmacological Treatments for Chagas Disease

Chagas disease remains a neglected tropical disease, causing significant burden in the Americas and countries that receive immigrants from endemic nations. Current pharmaceutical treatments are suboptimal, not only varying drastically in efficacy, depending on the stage of disease, but also presenting significant risk of adverse events. The objective of this review is to provide a timely update on the efficacy and safety of current trypanocidals. Eligible studies published from January 2015 to December 2020 were retrieved by one reviewer from six electronic databases. Ana-lysis was done with review management software and risk of bias was assessed using tools appropriate for the type of study (i.e., experimental or observational). Thirteen studies (10 observational and three RCTs) were included in the analysis. All 13 studies tested Benznidazole (BNZ) or Nifurtimox (NFX), and two studies also tested Posaconazole (POS) or E1224 (Ravucanazole). BNZ was found to be the most efficacious trypanocidal drug compared to Nifurtimox, POS, and E1224; it also resulted in the highest percentage of adverse effects (AEs) and treatment discontinuation due to its toxicity. Adults experienced higher frequency of neurological AEs while taking BNZ or NFX compared to children. Children had a higher frequency of general AEs compared to adults while taking BNZ. Overall, BNZ is still the most efficacious, but development of new, less toxic drugs is paramount for the quality of life of patients. Studies testing combination therapies and shorter regimens are needed, as is the devising of better clinical parameters and laboratory biomarkers to evaluate treatment efficacy. Considering the variability in methodology and reporting of the studies included in the present analysis, we offer some recommendations for the improvement and replicability of clinical studies investigating pharmacological treatment of Chagas disease. These include full disclosure of methodology, standardization of outcome measures, and always collecting and reporting data on both the efficacy of trypanocidals and on safety outcomes.

Recent trends in hospital admissions and outcomes of cardiac Chagas disease in the United States

Background:

Chagas disease (CD), caused by Trypanosoma cruzi, has been increasingly encountered as a cause of cardiovascular disease in the United States. We aimed to examine trends of hospital admissions and cardiovascular outcomes of cardiac CD (CCD).

Methods:

Search of 2003-2011 Nationwide Inpatient Sample database identified 949 (age 57±16 years, 51% male, 72.5% Hispanic) admissions for CCD.

Results:

A significant increase in the number of admissions for CCD was noted during the study period (OR=1.054; 95% CI=1.028-1.081; P< 0.0001); 72% were admitted to Southern and Western hospitals. Comorbidities included hypertension (40%), coronary artery disease (28%), hyperlipidemia (26%), tobacco use (12%), diabetes (9%), heart failure (5%) and obesity (2.2%). Cardiac abnormalities noted during hospitalization included atrial fibrillation (27%), ventricular tachycardia (23%), sinoatrial node dysfunction (5%), complete heart block (4%), valvular heart disease (6%)] and left ventricular aneurysms (5%). In-hospital mortality was 3.2%. Other major adverse events included cardiogenic shock in 54 (5.7%), cardiac arrest in 30 (3.2%), acute heart failure in 88 (9.3%), use of mechanical circulatory support in 29 (3.1%), and acute stroke in 34 (3.5%). Overall, 63% suffered at least one adverse event. Temporary (2%) and permanent (3.5%) pacemakers, implantable cardioverter defibrillators (10%), and cardiac transplant (2.1%) were needed for in-hospital management.

Conclusions:

Despite the remaining concerns about lack of awareness of CCD in the US, an increasing number of hospital admissions were reported from 2003-2011. Serious cardiovascular abnormalities were highly prevalent in these patients and were frequently associated with fatal and nonfatal complications.

Memory impairment in chronic experimental Chagas disease: Benznidazole therapy reversed cognitive deficit in association with reduction of parasite load and oxidative stress in the nervous tissue

Memory impairment has been associated with chronic Chagas disease (CD), a neglected tropical disease caused by the protozoan parasite Trypanosoma cruzi. In degenerative diseases, memory loss has been associated with increased oxidative stress, revealed as enhanced lipid peroxidation, in the cerebral cortex. Benznidazole (Bz), a trypanocidal drug efficient to reduce blood parasite load in the acute and chronic phases of infection, showed controversial effects on heart disease progression, the main clinical manifestation of CD. Here, we evaluated whether C57BL/6 mice infected with the Colombian type I T. cruzi strain present memory deficit assessed by (i) the novel object recognition task, (ii) the open field test and (iii) the aversive shock evoked test, at 120 days post infection (dpi). Next, we tested the effects of Bz therapy (25mg/Kg/day, for 30 consecutive days) on memory evocation, and tried to establish a relation between memory loss, parasite load and oxidative stress in the central nervous system (CNS). At 120 dpi, T. cruzi-infected mice showed memory impairment, compared with age-matched non-infected controls. Bz therapy (from 120 to 150 dpi) hampered the progression of habituation and aversive memory loss and, moreover, reversed memory impairment in object recognition. In vehicle-administered infected mice, neuroinflammation was absent albeit rare perivascular mononuclear cells were found in meninges and choroid plexus. Bz therapy abrogated the infiltration of the CNS by inflammatory cells, and reduced parasite load in hippocampus and cerebral cortex. At 120 and 150 dpi, lipid peroxidation was increased in the hippocampus and cortex tissue extracts. Notably, Bz therapy reduced levels of lipid peroxidation in the cerebral cortex. Therefore, in experimental chronic T. cruzi infection Bz therapy improved memory loss, in association with reduction of parasite load and oxidative stress in the CNS, providing a new perspective to improve the quality of life of Chagas disease patients.

Benznidazole decreases the risk of chronic Chagas disease progression and cardiovascular events: A long-term follow up study

BACKGROUND

Chagas disease (CD) remains an important endemic disease in Latin America. However, CD became globalized in recent decades. The majority of the chronically infected individuals did not receive etiologic treatment for several reasons, among them the most conspicuous is the lack of access to diagnosis. The impact of trypanocidal treatment on CD chronic phase, without cardiac involvement (indeterminate form ICF), is yet to be determined. We aimed to evaluate the effect of trypanocidal treatment with benznidazole (BZN) on the rate of progression to Chagas heart disease in patients with ICF.

METHODS

This is a retrospective cohort observational study including patients with ICF treated with BZN and compared to a group of non-treated patients matched for age, sex, region of origin, and the year of cohort entry. We reviewed the medical charts of all patients followed from May 1987 to June 2020 at the outpatient center of the Evandro Chagas National Institute of Infectious Diseases (INI) of the Oswaldo Cruz Foundation (Fiocruz), Rio de Janeiro, Brazil. Patients' follow-up included at least one annual medical visit and one annual electrocardiogram (ECG). Echocardiographic exams were performed at baseline and during the follow-up. Disease progression from ICF to cardiac form was defined by changes in baseline ECG. Cumulative incidence and the incidence rate were described in the incidence analysis. Cox proportional hazards models were used to estimate hazard ratios and 95% confidence intervals for the association between BZN and CD progression, cardiovascular events or death.

FINDINGS

One hundred and fourteen treated patients met the study inclusion criteria. A comparison group of 114 non-treated patients matched for age, sex, region of origin, and the year of cohort entry was also included, totalizing 228 patients. Most patients included in the study were male (70.2%), and their mean age was 31.3 (+7.4) years. Over a median follow-up of 15.1 years (ranging from 1.0 to 32.4), the cumulative CD progression incidence in treated patients was 7.9% vs. 21.1% in the non-treated group (p = 0.04) and the CD progression rate was 0.49 per 1.000 patients/year in treated patients vs. 1.10 per 1.000 patients/year for non-treated patients (p = 0.02). BZN treatment was associated with a decreased risk of CD progression in both unadjusted (HR 0.46; 95%CI 0.21 to 0.98) and adjusted (HR 0.43; 95%CI 0.19 to 0.96) models and with a decreased risk of occurrence of the composite of cardiovascular events only in the adjusted (HR 0.15; 95%CI 0.03 to 0.80) model. No association was observed between BZN treatment and mortality.

INTERPRETATION

In a long-term follow-up, BZN treatment was associated with a decreased incidence of CD progression from ICF to the cardiac form and also with a decreased risk of cardiovascular events. Therefore, our results indicate that BZN treatment for CD patients with ICF should be implemented into clinical practice.