Trypanosoma cruzi: parasite persistence in tissues in chronic chagasic Brazilian patients

Memórias do Instituto Oswaldo Cruz

Gláucia E Barbosa Marcon²  Dulcinéia Martins De Albuquerque²  Angelica Martins Batista²  Paula Durante Andrade²  Eros A Almeida²  Maria Elena Guariento²  Maria Ab Teixeira¹  Sandra C Botelho Costa² 

[1] ,Universidade Estadual de Campinas Faculdade de Ciências Médicas Departamento de Clínica MédicaCampinas SP ,Brasil

关键词: Trypanosoma cruzi;    real-time PCR;    nested PCR;    Chagas disease;   

DOI  :  10.1590/S0074-02762011000100014

来源: SciELO

【 摘 要 】

Chagas disease in the chronic phase may develop into cardiac and/or digestive forms. The pathogenesis of the disease is not yet clear and studies have been carried out to elucidate the role of parasite persistence in affected organs. The aim of this study was to detect and quantify Trypanosoma cruzi in paraffin-embedded tissue samples from chronic patients using NPCR (nested polymerase chain reaction) and QPCR (quantitative polymerase chain reaction) methods. These results were correlated to anatomopathological alterations in the heart and gastrointestinal tract (GIT). Of the 23 patients studied, 18 presented the cardiac form and five presented the cardiodigestive form of Chagas disease. DNA samples were randomly isolated from formalin-fixed paraffin-embedded sections of heart and GIT tissue of 23 necropsies and were analyzed through NPCR amplification. T. cruzi DNA was detected by NPCR in 48/56 (85.7%) heart and 35/42 (83.3%) GIT samples from patients with the cardiac form. For patients with the cardiodigestive form, NPCR was positive in 12/14 (85.7%) heart and in 14/14 (100%) GIT samples. QPCR, with an efficiency of 97.6%, was performed in 13 samples (11 from cardiac and 2 from cardiodigestive form) identified previously as positive by NPCR. The number of T. cruzi copies was compared to heart weight and no statistical significance was observed. Additionally, we compared the number of copies in different tissues (both heart and GIT) in six samples from the cardiac form and two samples from the cardiodigestive form. The parasite load observed was proportionally higher in heart tissues from patients with the cardiac form. These results show that the presence of the parasite in tissues is essential to Chagas disease pathogenesis.

【 授权许可】

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