Usefulness of PCR for Trypanosoma cruzi DNA in blood and endomyocardial biopsies for detection of Chagas disease reactivation after heart transplantation: A comparative study

BACKGROUND

Chagas disease reactivation (CDR) after heart transplantation is characterized by relapse of the infectious disease with proliferation and dissemination of Trypanosoma cruzi parasites. Serial blood PCR testing is consensually recommended for CDR monitoring, but there is uncertainty about the incremental value in performing the molecular tests in endomyocardial biopsies (EMB).

METHODS

We compared qualitative and quantitative results of PCR for T cruzi DNA in 62 pairs of blood and EMB collected with a maximum time interval of 7 days, from 34 heart-transplanted, chagasic patients.

RESULTS

Blood PCR resulted positive in 39/62 (62.9%) samples, with PL ranging from 0.14 to 1610.73 (median: 3.31). PCR resulted positive in 8/60 (13.3%) EMB, with PL ranging from 2.82 to 1670.55 (median: 65.63). All blood samples which tested negative presented a paired EMB which also tested negative. However, 31/39 (79.5%) blood samples which tested positive presented a paired EMB which tested negative. There was poor agreement between blood and EMB PCR (kappa = 0.153). CDR affecting the myocardium (myo-CDR) was diagnosed in three occasions. PCR resulted positive in both blood and EMB at the time of myo-CDR, with PL ranging from 0.61 to 1610.73 in blood and 13.8 to 1670.55 in EMB.

CONCLUSIONS

Negative PCR for T cruzi in blood rules out myo-CDR, with no value of testing EMB. Positive PCR in blood with high PL is diagnostic for myo-CDR. If PCR in blood results positive with low PL, testing EMB is useful: negative PCR turns unlikely, and positive PCR reinforces greatly the possibility of myo-CDR.

An autopsy-based study of Trypanosoma cruzi persistence in organs of chronic chagasic patients and its relevance for transplantation

BACKGROUND

Chagas' disease (CD) is caused by infection with the protozoan Trypanosoma cruzi. The disease can affect the heart and/or the gastrointestinal (GI) tract, but around 70% of infected individuals remain asymptomatic in the chronic form. Organ transplantation from T. cruzi-infected donors is often avoided because of the risk of disease transmission, previously reported after heart, kidney, or liver transplantation.

METHODS

We investigated by histology, immunohistochemistry, and polymerase chain reaction (PCR) the persistence of T. cruzi in samples of the heart, lung, liver, kidney, pancreas, adrenal gland, esophagus, and GI tract of 21 chronic chagasic patients.

RESULTS

Parasite persistence was detected in 12/21 (57.1%) heart samples, mainly by PCR-based assays. T. cruzi parasites were detected by histology and immunohistochemistry in smooth muscle cells of the central vein from 1/21 (4.8%) adrenal gland samples. No samples of the lung, liver, kidney, pancreas, esophagus, or GI tract were found to have parasites by histology, immunohistochemistry, or PCR.

CONCLUSIONS

We concluded that, aside from the heart, the other solid organs of T. cruzi-infected donors can be used for transplantation with a lot of caution. Such organs are not safe in the view of previous reports of CD transmission, but seem to present a low T. cruzi load compared to the heart.

Troponin in diabetic patients with and without chronic coronary artery disease

BACKGROUND

Cardiac-specific troponin detected with the new high-sensitivity assays can be chronically elevated in response to cardiovascular comorbidities and confer important prognostic information, in the absence of unstable coronary syndromes. Both diabetes mellitus and coronary artery disease are known predictors of troponin elevation. It is not known whether diabetic patients with coronary artery disease have different levels of troponin compared with diabetic patients with normal coronary arteries. To investigate this question, we determined the concentrations of a level 1 troponin assay in two groups of diabetic patients: those with multivessel coronary artery disease and those with angiographically normal coronary arteries.

METHODS

We studied 95 diabetic patients and compared troponin in serum samples from 50 patients with coronary artery disease (mean age = 63.7, 58 % male) with 45 controls with angiographically normal coronary arteries. Brain natriuretic peptide and the oxidative stress biomarkers myeloperoxidase, nitrotyrosine and oxidized LDL were also determined.

RESULTS

Diabetic patients with coronary artery disease had higher levels of troponin than did controls (median values, 12.0 pg/mL (95 % CI:10-16) vs 7.0 pg/mL (95 % CI: 5.9-8.5), respectively; p = 0.0001). The area under the ROC curve for the diagnosis of CAD was 0.712 with a sensitivity of 70 % and a specificity of 66 %. Plasma BNP levels and oxidative stress variables (myeloperoxidase, nitrotyrosine, and oxidized LDL) were not different between the two groups. In a multivariate analysis, gender (p = 0.04), serum glucose (0.03) and Troponin I (p = 0.01) had independent statistical significance.

CONCLUSION

Troponin elevation is related to the presence of chronic coronary artery disease in diabetic patients with multiple associated cardiovascular risk factors. Troponin may serve as a biomarker in this high-risk population.

TRIAL REGISTRATION

http://www.controlled-trials.com

REGISTRATION NUMBER

ISRCTN26970041.

A role for archaeal organisms in development of atherosclerotic vulnerable plaques and myxoid matrices

PURPOSE

Vulnerable plaques are characterized by a myxoid matrix, necrotic lipidic core, reactive oxygen species, and high levels of microorganisms. Aerobic microbes such as Chlamydophila pneumoniae and Mycoplasma pneumoniae usually do not survive in oxidative stress media. Archaea are anaerobic microbes with powerful anti-oxidative enzymes that allow detoxification of free radicals whose presence might favor the survival of aerobic microorganisms. We searched for archaeal organisms in vulnerable plaques, and possible associations with myxoid matrix, chlamydia, and mycoplasma bodies.

METHODS

Twenty-nine tissue samples from 13 coronary artherectomies from large excentric ostial or bifurcational lesions were studied using optical and electron microscopy. Infectious agents compatible with archaea, chlamydia, and mycoplasma were semiquantified using electron micrographs and correlated with the amounts of fibromuscular tissue, myxoid matrix, and foam cells, as determined from semi-thin sections. Six of the cases were also submitted to polymerase chain reaction with archaeal primers.

RESULTS

All 13 specimens showed archaeal-compatible structures and chlamydial and mycoplasmal bodies in at least 1 sample. There was a positive correlation between extent of the of myxoid matrix and archaeal bodies (r = 0.44, P = 0.02); between archaeal and mycoplasmal bodies (r = 0.41, P = 0.03), and between chlamydial bodies and foam cells (r = 0.42; P = 0.03). The PCR test was positive for archaeal DNA in 4 of the 6 fragments.

DISCUSSION

DNA and forms suggestive of archaea are present in vulnerable plaques and may have a fundamental role in the proliferation of mycoplasma and chlamydia. This seems to be the first description of apparently pathogenic archaea in human internal organ lesions.

Polymerase chain reaction in endomyocardial biopsies for monitoring reactivation of Chagas' disease in heart transplantation

Polymerase chain reaction (PCR) has been used to detect microbiological agent recurrence after heart transplantation of viral-induced cardiomyopathies. We report a case of reactivation of Chagas' disease after heart transplantation in which parasites could be detected in the endomyocardial biopsy using hematoxylin-eosin-stained sections, immunohistochemistry, and PCR for Trypanosoma cruzi DNA. Interestingly, PCR results remained positive in the endomyocardial biopsy 53 days after the beginning of successful treatment, pointing to the possibility of chronic persistence of parasites in the myocardium after the reactivation of Chagas' disease.