Trypanosoma cruzi maxicircle heterogeneity in Chagas disease patients from Brazil

The majority of individuals in the chronic phase of Chagas disease are asymptomatic (indeterminate form, IF). Each year, similar to 3% of them develop lesions in the heart or gastrointestinal tract. Cardiomyopathy (CCHD) is the most severe manifestation of Chagas disease. The factors that determine the outcome of the infection are unknown, but certainly depend on complex interactions amongst the genetic make-up of the parasite, the host immunogenetic background and environment. In a previous study we verified that the maxicircle gene NADH dehydrogenase (mitochondrial complex 1) subunit 7 (ND7) from IF isolates had a 455 bp deletion compared with the wild type (WT) ND7 gene from CCHD strains. We proposed that ND7 could constitute a valuable target for PCR assays in the differential diagnosis of the infective strain. In the present study we evaluated this hypothesis by examination of ND7 structure in parasites from 75 patients with defined pathologies, from Southeast Brazil. We also analysed the structure of additional mitochondrial genes (ND4/CR4, COIII and COII) since the maxicircle is used for clustering Trypanosoma cruzi strains into three clades/haplogroups. We conclude that maxicircle genes do not discriminate parasite populations which induce IF or CCHD forms. Interestingly, the great majority of the analysed isolates belong to T cruzi 11 (discrete typing unit, (DTU) IIb) genotype. This scenario is at variance with the prevalence of hybrid (DTU IId) human isolates in Bolivia, Chile and Argentina. The distribution of WT and deleted ND7 and ND4 genes in T cruzi strains suggests that mutations in the two genes occurred in different ancestrals in the T cruzi 11 cluster, allowing the identification of at least three mitochondrial sub-lineages within this group. The observation that T. cruzi strains accumulate mutations in several genes coding for complex I subunits favours the hypothesis that complex I may have a limited activity in this parasite. (C) 2009 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.

Fundacao de Amparo A Pesquisa do Estado de Sao Paulo (FAPESP)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Ministerio de Ciencia e Tecnologia/Conselho Nacional de Desenvolvimento Cientifico e Tecnolegico/Ministerio da Sadde (MCT/CNPq/MS-SCTIE-DECIT-Edital de Doenqas Negligenciadas)

Ministerio de Ciencia e Tecnologia/Conselho Nacional de Desenvolvimento Cientifico e Tecnolegico/Ministerio da Sadde (MCT/CNPq/MS-SCTIE-DECIT-Edital de Doenqas Negligenciadas)

Fundacao de Amparo a Pesquisa do Estado de Minas Gerais (FAPEMIG)

Fundacao de Amparo a Pesquisa do Estado de Minas Gerais (FAPEMIG)

NIH[A105e034]

NIH

Universidad del Tolima (Ibague, Colombia)

Universidad del Tolima (Ibague, Colombia)

Instituto Colombiano Francisco Jose de Caldas (COLCIENCIAS)

Instituto Colombiano Francisco Jose de Caldas (COLCIENCIAS)