Troponin in Chagas disease

Abstract

Chagas disease is still a major tropical diseasein Latin America, affecting 16 to 18 million people.About 6 million people are infected with thecausative organism, Trypanosoma cruzi , in Brazil[1]. However, it often remains for decades in itsindeterminate form, symptomless, with tissue injuryin about 30% of the cases, which eventually willevolve to serious arrhythmia and sudden death [1].There is no effective clinical or laboratorytechnique to monitor chronic Chagas myocarditis.Several researchers have found that Troponin I andT are important biochemical markers of heartmuscle damage. Increased levels of myocardialtroponins have been found associated with acutemyocardial ischemia, infarction, myocarditis andheart failure [2-4].Recently, we tested sera from 60 Chagasdisease patients (24 with the indeterminate formand 36 with chronic chagasic cardiomyopathy. Serafrom 24 healthy volunteers (Control Group) weretested for Troponin I (Immulite 1000 Turbo DPC-Medlab). The Troponin I value was considerednormal when it was below 0.15ng/dl, and high whenit was above 0.30ng/dl. The upper limit was set tobe at least two standard deviations above thenormal value.The mean value for Troponin I was 0.46ng/dl inthe Chagas disease patients, and 0.027ng/dl in thecontrol group. The mean age was 44.1±9.9 yearsof the Chagas patients, and 34 were male. Whenwe tested We found 13 (54%) and 26 (74%)patients with high Troponin I, respectively, forchronic Chagas cardiomyopathy and theindeterminate form of Chagas disease. Twenty-onepatients from the Chagas disease group wereexcluded due to other cardiovascular diseases,myopathy or kidney disease.Troponin I levels were significantly higher amongthe Chagas disease patients with cardiomyopathywhen compared to the indeterminate form andcontrols, mean 0.60ng/dl vs 0.25ng/dl, respectively,and controls 0.027ng/dl (P < 0.001).All the patients with the indeterminate form ofChagas disease had normal EKGs, chest X-raysand echocardiograms. Possibly, the increased levelsof Troponin I, found in our sample, are related tochronic foci of myocardial inflammation, provokedby Chagas disease.Moreover, the utilization of a sensitive and easilymeasured biochemical marker should allow us toadopt different clinical cut-offs, facilitating theidentification of the different degrees of myocardialdamage, which now requires various diagnostic andtherapeutic approaches [5].The serum level of Troponin I is elevated indifferent clinical presentations of Chagas’ diseaseand may become an important element for earlydetection of myocardial inflammation, to preventfurther myocardial damage.References