Trypanosoma cruzi Reactivation in the Brain

Chagas disease in immunocompromised patients

SUMMARYAs Chagas disease remains prevalent in the Americas, it is important that healthcare professionals and researchers are aware of the screening, diagnosis, monitoring, and treatment recommendations for the populations of patients they care for and study. Management of Trypanosoma cruzi infection in immunocompromised hosts is challenging, particularly because, regardless of antitrypanosomal treatment status, immunocompromised patients with Chagas disease are at risk for T. cruzi reactivation, which can be lethal. Evidence-based practices to prevent and manage T. cruzi reactivation vary depending on the type of immunocompromise. Here, we review available data describing Chagas disease epidemiology, testing, and management practices for various populations of immunocompromised individuals, including people with HIV and patients undergoing solid organ and hematopoietic stem cell transplantation.

Trypanosoma cruzi Central Nervous System Infection-Pathogenesis, Clinical Manifestations, Diagnosis, and Treatment

Purpose of Review

Chagas disease (CD) is a neglected tropical disease from the American continent that commonly causes cardiovascular disease. Some patients develop neurological manifestations. We discuss and summarize the pathogenesis, clinical characteristics, diagnosis, and treatment of the central nervous system manifestations of CD.

Recent Findings

Cerebrospinal fluid quantitative polymerase chain reaction tests and next-generation sequencing in tissue samples have facilitated disease diagnosis and follow-up. Novel presentations, including retinitis, are now reported. A new MRI sign called "Bunch of açai berries appearance"-multiple hypointense nodular lesions-has been described recently. Treatment with benznidazole at higher doses and the role of therapeutic drug monitoring need to be further studied in this setting.

Summary

A high suspicion index is paramount to diagnosing Chagas' central nervous system involvement. Standardized molecular diagnostics can aid in the initial workup. Future development of new therapeutic drugs is crucial because of the toxicity profile of the currently available medications.

Screening for Chagas disease should be included in entry-to-care testing for at-risk people with HIV living in the United States

Chagas disease screening of at-risk populations is essential to identify infected individuals and facilitate timely treatment before end-organ damage occurs. Co-infected people with HIV (PWH) are at risk for dangerous sequelae, specifically Trypanosoma cruzi reactivation disease. Recently published national recommendations indicate that at-risk PWH, particularly those from endemic areas or born to women from endemic areas, should be screened via a sensitive anti-T. cruzi IgG assay. However, immunocompromised patients with negative serologic results may warrant further investigation. Reactivation should be suspected in at-risk, untreated PWH with low CD4 cell counts presenting with acute neurologic or cardiac symptoms; these patients should be promptly evaluated and treated. One pragmatic solution to improve Chagas disease screening among PWH and thereby reduce T. cruzi -related morbidity and mortality is to incorporate Chagas disease screening into the panel of tests routinely performed during the entry-to-care evaluation for at-risk PWH.

Chagas Disease in People with HIV: A Narrative Review

Many questions remain unanswered regarding the epidemiology, pathophysiology, diagnosis, treatment, and monitoring of Trypanosoma cruzi infection in people with HIV (PWH). The reported prevalence of T. cruzi infection in PWH living in endemic countries ranges from 1-28% and is likely similar in at-risk US populations. While classic cardiac and gastrointestinal presentations of chronic Chagas disease occur in PWH, PWH are additionally at risk for a severe and often fatal form of T. cruzi-mediated disease called reactivation disease. T. cruzi reactivation typically occurs in PWH with low CD4 counts and poor virologic control. National HIV guidelines in several endemic South American countries recommend that all PWH be screened for T. cruzi infection at the time of HIV diagnosis; however, this recommendation is not widely implemented. The early detection of T. cruzi infection in PWH is critical as the sequelae of Chagas disease, including T. cruzi reactivation, may be preventable through the restoration of robust cellular immunity via the initiation of antiretroviral therapy and the appropriate use of antitrypanosomal therapy.

Antitrypanosomal Lactones from Nectandra barbellata

Twigs of Nectandra barbellata were extracted using a solution of the ionic liquid 1-butyl-3-methylimidazolium bromide (BMImBr) in H₂O, assisted by microwave (MAE). After successive chromatographic steps, one sesquiterpene, costic acid, and three new related lactones, (R)-3(7)-Z-3-hexadec-21-enylidene-5-(hydroxymethyl)tetrahydrofuran-2-one (1), (R)-3(7)-Z-3-hexadecylidene-5-(hydroxymethyl)tetrahydrofuran-2-one (2), and (R)-3(7)-Z-3-docosylidene-5-(hydroxymethyl)tetrahydrofuran-2-one (3), were isolated. After structural elucidation using IR, UV, HRESIMS, NMR, ECD, and VCD, compounds 1-3 were tested against trypomastigote forms of Trypanosoma cruzi. The mechanism of action of bioactive isolated compounds was studied using different fluorescent-based approaches to investigate alterations of the plasma membrane, permeability/electric potential (ΔΨ_p), reactive oxygen species levels, mitochondria (electric membrane potential, ΔΨ_m/ATP levels), Ca²⁺ levels, and pH of the acidocalcisomes. In addition, in silico studies predicted no resemblance to pan assay interference compounds (PAINS).

Priming Astrocytes With HIV-Induced Reactive Oxygen Species Enhances Their Trypanosoma cruzi Infection

Introduction: Trypanosoma cruzi is an intracellular protozoa and etiological agent that causes Chagas disease. Its presence among the immunocompromised HIV-infected individuals is relevant worldwide because of its impact on the central nervous system (CNS) causing severe meningoencephalitis. The HIV infection of astrocytes – the most abundant cells in the brain, where the parasite can also be hosted – being able to modify reactive oxygen species (ROS) could influence the parasite growth. In such interaction, extracellular vesicles (EVs) shed from trypomastigotes may alter the surrounding environment including its pro-oxidant status.

Methods: We evaluated the interplay between both pathogens in human astrocytes and its consequences on the host cell pro-oxidant condition self-propitiated by the parasite – using its EVs – or by HIV infection. For this goal, we challenged cultured human primary astrocytes with both pathogens and the efficiency of infection and multiplication were measured by microscopy and flow cytometry and parasite DNA quantification. Mitochondrial and cellular ROS levels were measured by flow cytometry in the presence or not of scavengers with a concomitant evaluation of the cellular apoptosis level.

Results: We observed that increased mitochondrial and cellular ROS production boosted significantly T. cruzi infection and multiplication in astrocytes. Such oxidative condition was promoted by free trypomastigotes-derived EVs as well as by HIV infection.

Conclusions: The pathogenesis of the HIV-T. cruzi coinfection in astrocytes leads to an oxidative misbalance as a key mechanism, which exacerbates ROS generation and promotes positive feedback to parasite growth in the CNS.

Approach to an Intracranial Mass in Patients With HIV

PURPOSE OF REVIEW

Space-occupying lesions represent a diagnostic challenge among people with the human immunodeficiency virus, acquired immunodeficiency syndrome (HIV/AIDS). To determine the best diagnostic approach to the wide array of possible etiologies and provide a thorough interpretation of neuroimaging in order to narrow a hierarchical differential diagnosis among these patients. Given that there is no pathognomonic neuroimaging pattern in this clinical setting, we searched results from brain biopsies to best determine the etiology of commonly found lesions.

RECENT FINDINGS

Multimodal brain MRI and MRI spectroscopy (MRS) often provide the most valuable information in the study of focal masses among people with HIV/AIDS. Brain biopsy appears safe and provides high diagnostic yields in these patients. Among patients with HIV/AIDS who present with space-occupying intracranial lesions, brain MRI and MRS are useful tests. However, in cases of diagnostic uncertainty, brain biopsy is a safe procedure and should be performed. The role of metabolic studies like ²⁰¹Th-SPECT or PET is useful in the detection of primary central nervous system lymphoma.