Phenotypic diversity and drug susceptibility of Trypanosoma cruzi TcV clinical isolates

Abstract

Trypanosoma cruzi is a genetically heterogeneous group of organisms that cause Chagas disease. It has been long suspected that the clinical outcome of the disease and response to therapeutic agents are, at least in part, related to the genetic characteristics of the parasite. Herein, we sought to validate the significance of the genotype of T. cruzi isolates recovered from patients with different clinical forms of Chagas disease living in Argentina on their biological behaviour and susceptibility to drugs. Genotype identification of the newly established isolates confirmed the reported predominance of TcV, with a minor frequency of TcI. Epimastigote sensitivity assays demonstrated marked dissimilar responses to benznidazole, nifurtimox, pentamidine and dihydroartemisinin in vitro. Two TcV isolates exhibiting divergent response to benznidazole in epimastigote assays were further tested for the expression of anti-oxidant proteins. Benznidazole-resistant BOL-FC10A epimastigotes had decreased expression of Old Yellow Enzyme and cytosolic superoxide dismutase, and overexpression of mitochondrial superoxide dismutase and tryparedoxin- 1, compared to benznidazole-susceptible AR-SE23C parasites. Drug sensitivity assays on intracellular amastigotes and trypomastigotes reproduced the higher susceptibility of AR-SE23C over BOL-FC10A parasites to benznidazole observed in epimastigotes assays. However, the susceptibility/resistance profile of amastigotes and trypomastigotes to nifurtimox, pentamidine and dihydroartemisinin varied markedly with respect to that of epimastigotes. C3H/He mice infected with AR-SE23C trypomastigotes had higher levels of parasitemia and mortality rate during the acute phase of infection compared to mice infected with BOL-FC10A trypomastigotes. Treatment of infected mice with benznidazole or nifurtimox was efficient to reduce patent parasitemia induced by either isolate. Nevertheless, qPCR performed at 70 dpi revealed parasite DNA in the blood of mice infected with AR-SE23C but not in BOL-FC10A infected mice. These results demonstrate high level of intra-type diversity which may represent an important obstacle for the testing of chemotherapeutic agents.

Hybrids of Cinchona Alkaloids and Bile Acids as Antiparasitic Agents Against Trypanosoma cruzi

“…Differential susceptibility of the different life cycle stages of the parasite within the same strain [18] should be also considered. In this regard, Bz and Nf effectiveness against axenic epimastigotes and the intracellular stages of T. cruzi have been already reported [19]. Furthermore, drug sensitivity exhibited by the extracellular forms (i.e., epimastigotes and trypomastigotes) could sometimes be higher than the sensitivity of the intracellular form of the parasite, in part because of its intracellular availability [20] More importantly, given that in the chronic phase of Chagas disease, current chemotherapy is not efficient and that parasitemia is usually low, performing new drug screenings on the intracellular replicative stage of the parasite appears to be the better approach.…”

Experimental Nanovaccine Offers Protection Against Repeat Exposures to Trypanosoma cruzi Through Activation of Polyfunctional T Cell Response

“…Yet, many adults do not complete the therapeutic regimen due to adverse events that can also contribute to drug resistance in T. cruzi (32), and these drugs are contraindicated for the treatment of pregnant women (33) and Chagas patients with clinical manifestations of cardiac disease (34)(35)(36). Further, T. cruzi isolates from heterogenous background are not equally susceptible to these drugs (37,38). It is, thus, believed by the research community that an overall increase in access to antiparasite therapies will limit the disease progression in infected individuals and vaccines are needed to prevent the spread of T. cruzi and Chagas disease (39,40).…”

Precision Health for Chagas Disease: Integrating Parasite and Host Factors to Predict Outcome of Infection and Response to Therapy

“…TcII strains, represented by the common laboratory strain Y, generally exhibit high virulence and may produce mega disease as well as cardiac disease in chronic infection (De Oliveira et al, 2008;Oliveira et al, 2017). In contrast, people from Argentina and Bolivia frequently are infected with TcV strains and frequently develop cardiomyopathy (Zuñiga et al, 1997;Messenger et al, 2015;Quebrada Palacio et al, 2018;Zingales, 2018). Other DTUs such as TcI (e.g., Colombian) or TcVI (e.g., Tulahuen) have a tendency not to cause clinical disease and are often used in chronic indeterminate mouse models of infection (Chandra et al, 2002;Santana et al, 2014).…”

“…Several have proposed that different T. cruzi DTU have different resistance to BNZ and NFX (Cencig et al, 2012;Teston et al, 2013). Some DTU are more resistant to BNZ than others, although even within a single DTU there can be variability in BNZ sensitivity (Quebrada Palacio et al, 2018). Interestingly, parasite strains of different DTUs do show common BNZ susceptibility and resistance patterns (Revollo et al, 2019).…”