Eros Antonio de Almeida

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

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.

ENDOTHELIAL DYSFUNCTION IN CORONARY VESSELS AND THORACIC AORTA OF RATS EXPOSED TO CIGARETTE SMOKE

1. The aim of this study was to evaluate the role of endothelium in mediating the response to acetylcholine in the thoracic aorta and coronary vessels of rats exposed to cigarette smoking. Total serum cholesterol was measured at the beginning and end of the experiment.

Serological profiles and evaluation of parasitaemia by PCR and blood culture in individuals chronically infected by Trypanosoma cruzi treated with benzonidazole

Objective  To evaluate the serological and parasitological status of patients with chronic Chagas disease (CD) after chemotherapy with benzonidazole.

Evidence of Chagas disease in seronegative Brazilian patients with megaesophagus.

BACKGROUND After 100 years of research, Chagas disease (CD) remains an important public health problem in Latin America. The symptomatic chronic phase is usually characterized by cardiac or digestive involvement and diagnosis currently relies on the measurement of Trypanosoma cruzi-specific antibodies produced in response to the infection. However, the detection of parasite DNA in seronegative persons has been reported. METHODS The prevalence of CD in a population with esophageal disorders was assessed by conventional serology. We also detected T. cruzi DNA in blood samples of seronegative and inconclusive patients by nested polymerase chain reaction (N-PCR). RESULTS The seroprevalence of CD determined by conventional serologic tests (indirect immunofluorescence (IIF) and enzyme-linked immunosorbent assay (ELISA)) was 79% in 513 patients with esophageal disorders. Out of 41 blood samples, N-PCR was positive in 31 (76%) cases for which serology was negative or inconclusive. CONCLUSIONS As all patients presented with clinical signs suggestive of the digestive form of CD and most of them were born in endemic areas, we highlight the importance of improving diagnosis of the disease and the implications for blood bank screening. Our data suggest that N-PCR is effective in the detection of T. cruzi DNA in patients with inconclusive or negative serology, and it may eventually be useful in the determination of the etiology of megaesophagus.

Determining the C-Reactive Protein Level in Patients With Different Clinical Forms of Chagas Disease

Chagas disease is caused by Trypanosoma cruzi and remains a health problem in the developing countries of South America. The condition leads to cardiac conduction disturbances and chronic heart failure. In this study, 136 individuals were evaluated by the Chagas Disease Study Group of the Hospital de la Universidad Estatal de Campinas in Brazil to determine the relationship between chronic heart failure and the serum C-reactive protein (CRP) level. When patients were stratified according to the different clinical presentations of Chagas disease, it was found that the CRP levels in those with severe heart disease and non-Chagasic cardiopathy were significantly higher than in controls or those with mild heart disease (P< .05), even when participants were stratified by age (i.e. <40 and > or =40 years). There was a direct linear correlation between age and CRP level, such that the older the individual, the higher the CRP level. These data provide further evidence for an association between chronic inflammation and the development of heart failure. Although CRP elevations are not exclusively related to Chagas disease, the CRP level may be a useful marker for the progression of Chagas disease to a more advanced phase.

Apresentação clínica da doença de Chagas crônica em indivíduos idosos

This study had the aim of evaluating the clinical presentation of chronic Chagas disease among the elderly. It was a retrospective analysis of clinical records at an outpatient referral service. The sample was divided into two groups: elderly (>or= 60 years old) and non-elderly. Sex, comorbidities, clinical form, electrocardiogram and serological titers were evaluated. In the elderly group (61 cases), the mean age was 66.03+/-5 years; 67.2% were female; 59% presented comorbidities (most frequently systemic arterial hypertension, in 39.3%); 1.6% had the indeterminate clinical form, 88.5% the cardiac form and 36% the digestive form; and abnormalities were frequently found on electrocardiograms: 41% presented anterosuperior left bundle branch block (AS-LBBB), 32.8% presented right bundle branch block (RBBB) and 22.9% presented ventricular ectopic beats (VEB). In the non-elderly group (61 cases), the mean age was 39.30+/-8.36 years; 54.1% were female; 50.8% presented comorbidities (most frequently systemic arterial hypertension, in 26.2%); 18% had the indeterminate clinical form (p<0.05), 78.7% the cardiac form and 32.8% the digestive form; and abnormalities were frequently found on electrocardiogram: 24.6% presented AS-LBBB, 21.3% RBBB and 18% VEB. It was concluded that there were no clinical differences between elderly and non-elderly Chagas patients. The indeterminate clinical form predominated in patients less than 60 years old.

Chagasic megaesophagus and megacolon diagnosed in childhood and probably caused by vertical transmission

Reports on children presenting symptoms compatible with the chronic phase of Chagas disease are sporadic. We report a case of a 7-year-old boy who had megaesophagus and megacolon, both of them a consequence of the trypanosomiasis. The etiology was established by means of laboratory and histological features. Based on epidemiological data, the authors concluded that vertical transmission was the most probable route of acquisition. This diagnosis should be considered in children presenting similar complaints, even those living away from endemic areas.

Endothelial dysfunction, lipid peroxidation and cholesterol level in rabbit arteries: relationship to progressive hypercholesterolemia

Objective The aim of this study was to evaluate the influence of a gradual increase in the plasma total cholesterol concentration and of lipid peroxidation on endothelial function in rabbit arteries. Material and methods Fifty male New Zealand white rabbits were fed a diet enriched with 0.5% cholesterol and 10% coconut oil and were allocated to one of nine groups (G2 to G10) based on sequential determinations of their plasma total cholesterol concentration (each group covered an interval of 100 mg/dL). The control group (G1) consisted of five rabbits fed a non-supplemented diet. The rabbits were killed at the end of the treatment and the total plasma cholesterol concentration, arterial wall cholesterol level and lipid peroxidation based on the quantification of malondialdehyde were determined using commercial kits. Endothelial function was assessed based on concentration-response curves to acetylcholine and sodium nitroprusside in aortic segments. Results Treatment with a cholesterol-rich diet resulted in disproportional increases in the arterial wall cholesterol concentration, lipid peroxidation and a disproportional decrease in the maximum endothelium-dependent relaxations in relation to the plasma total cholesterol concentration. However, the maximum endothelium-dependent relaxations were proportional to the increase in the arterial wall content of malondialdehyde. Conclusions These results show that the levels of arterial wall cholesterol, lipid peroxidation and endothelial dysfunction are not proportional to the degree of hypercholesterolemia, although endothelial dysfunction is proportional to the extent of lipid peroxidation in the vessel wall.