ABSTRACT
In the late phase of Trypanosoma cruzi infection, parasite persistence and an exaggerated immune response accompanied by oxidative stress play a crucial role in the genesis of Chronic Chagasic Cardiomyopathy (CCC). Current treatments (Benznidazole (BNZ) and Nifurtimox) can effect only the elimination of the parasite, but are ineffective for late stage treatment and for preventing heart damage and disease progression. In vivo trypanocidal and cardioprotective activity has been reported for Lippia alba essential oils (EOs), ascribed to their two major terpenes, limonene and caryophyllene oxide. To investigate the role of antioxidant and immunomodulatory mechanisms behind these properties, chronic-T. cruzi-infected rats were treated with oral synergistic mixtures of the aforementioned EOs. For this purpose, the EOs were optimized through limonene-enrichment fractioning and by the addition of exogenous caryophyllene oxide (LIMOX) and used alone or in combined therapy with subtherapeutic doses of BNZ (LIMOXBNZ). Clinical, toxicity, inflammatory, oxidative, and parasitological (qPCR) parameters were assessed in cardiac tissue. These therapies demonstrated meaningful antioxidant and immunomodulatory activity on markers involved in CCC pathogenesis (IFN-γ, TNF-α, IL-4, IL-10, and iNOS), which could explain their significant trypanocidal properties and their noteworthy role in preventing, and even reversing, the progression of cardiac damage in chronic Chagas disease.
ABSTRACT
INTRODUCTION: Chagas' disease is the leading cause of infectious myocarditis worldwide. This infection caused by Trypanosoma cruzi is usually life-long and asymptomatic; however, the third part of infected people can develop severe or even fatal cardiomyopathy. As the parasitemia in the chronic phase is both low-grade and intermittent, T. cruzi infection is principally detected by serology, although this method has sensitivity and specificity limitations. OBJECTIVE: To determine the level of agreement between serologic and molecular tests in 658 voluntary blood donors from six provinces in the Colombian department of Santander. MATERIALS AND METHODS: We evaluated an array of diagnostic technologies by cross-section sampling performing a serological double diagnostic test for T. cruzi antibody detection (Chagas III ELISA™, BiosChile Group, and ARCHITECT Chagas CMIA™, Abbott), and DNA detection by polymerase chain reaction (PCR). We collected the demographic, clinical, and epidemiological information of participants. The sample size was calculated using Epidat™ and the statistical analysis was done with Stata 12.1™. RESULTS: PCR was six times more sensitive in detecting T. cruzi infection than ELISA/CMIA with prevalence values of 1.8% (12/658) and 0.3% (2/658), respectively, and kappa=0.28 (95%CI: -0.03 - 0.59). In contrast, serology showed a sensitivity of 16.7% (95%CI: 2.09 - 48.4) and a specificity of 100% (95%CI: 99.4 - 100). All seropositive samples were found to be positive by PCR. CONCLUSIONS: The implementation of PCR as a complementary method for screening donors could reduce the probability of false negative and the consequent risk of transfusional-transmission of Chagas' disease, especially in endemic regions.
Introducción. La enfermedad de Chagas constituye la principal causa de miocarditis infecciosa en el mundo. Causada por Trypanosoma cruzi, la infección puede persistir toda la vida de manera asintomática y silenciosa, pero un tercio de los infectados desarrolla cardiomiopatía grave. Debido a que la parasitemia en la fase crónica es baja e intermitente, el diagnóstico se hace principalmente mediante la detección de anticuerpos (serología), método que tiene limitaciones de sensibilidad y especificidad. Objetivo. Determinar la concordancia entre el diagnóstico serológico y molecular de T. cruzi en 658 donantes voluntarios de sangre del departamento de Santander, Colombia. Materiales y métodos. Se hizo un estudio de evaluación de tecnologías diagnósticas con muestreo transversal, utilizando un doble diagnóstico serológico para la detección de anticuerpos anti-T. cruzi (Chagas III ELISA™, BiosChile Group, y ARCHITECT Chagas CMIA™, Abbott) y la de ADN por PCR. Se recolectó la información demográfica, clínica y epidemiológica de los participantes. El tamaño de la muestra se estimó utilizando Epidat™ y el análisis estadístico se hizo mediante Stata 12.1™. Resultados. La sensibilidad de la PCR fue seis veces mayor que la de las pruebas de ELISA/CMIA, con prevalencias de 1,8 % (12/658) y 0,3 % (2/658), respectivamente, y kappa de 0,28 (IC95% -0,03 - 0,59). La sensibilidad serológica fue de 16,7 % (IC95% 2,09 - 48,4) y la especificidad de 100 % (IC95% 99,4 - 100). Todas las muestras seropositivas fueron positivas también en la PCR. Conclusiones. El uso de la PCR como método complementario para la tamización de donantes podría reducir el riesgo de falsos negativos y disminuir los casos de transmisión transfusional de la enfermedad de Chagas, especialmente en regiones endémicas.
