Cardiac autonomic dysfunction and neuroganglionitis in a rat model of chronic Chagas' disease.

OBJECTIVE: The aim was to evaluate whether the cardiac parasympathetic function in a rat model of chronic Chagas' disease is impaired as in the human disease, and to correlate the functional state to histopathology of the intrinsic autonomic innervation of heart. METHODS: 70 male Wistar rats 8 months infected with strains Y (n = 22), São Felipe (n = 18), and Colombia (n = 30) of Trypanosoma cruzi, were compared with 20 age and sex matched non-infected controls. Baroreflex bradycardia was quantified after multiple bolus injections of phenylephrine (3 to 12 micrograms). For each rat studied a mean was obtained of the absolute and relative (delta %) ratio (index) between the maximum heart rate decrease and the maximum systolic blood pressure increase. RESULTS: For the relative index the means were smaller (p less than 0.05) in the Y [-0.52(SD 0.19)%], São Felipe [-0.45(0.28)%], and Colombia [-0.53(0.21%)] subgroups, as well as in the pooled chagasic group [-0.51(0.22)%], than in the control group [-0.64(0.13)%]. In 32% (7/22), 33% (6/18), and 20% (6/30) of rats infected with Y, São Felipe, and Colombia strains, respectively, and in 27% (19/70) of the pooled group rats, the index exceeded the control group mean by -2 SD. After atropinisation, a similar pronounced reduction (p less than 0.01) in the index was observed in all groups [-84(28)% to -95(17)%]; however, rats with depressed bradycardia showed a smaller (p less than 0.05) reduction in the relative index than control rats, at -70(34) v -92(16%). Inflammatory and degenerative lesions of the intrinsic cardiac innervation were observed in 87% of the rats with autonomic dysfunction. Rats with the lesions showed a mean relative index that was smaller than those without lesions, at -0.44(0.23) v -0.64(0.20)% (p less than 0.01), and also smaller than in the controls. CONCLUSIONS: Cardiac autonomic dysfunction expressed by reduced baroreflex bradycardia was detected in rats chronically infected with T cruzi, as in human Chagas' disease. The disturbance, shown for the first time in an animal model of chagasic infection, resulted primarily from impaired efferent parasympathetic activity caused by intrinsic neuroganglionar lesions.

Neuron count reevaluation in the myenteric plexus of chagasic megacolon after morphometric neuron analysis.

This study was made with the objective of reevaluating the colon denervation in chronic Chagas' disease. The diameters of neuron perikaryons of the myenteric plexus were measured on paraffin sections in a ring from the sigmoid in Chagas' disease patients, 17 with and 10 without megacolon and in 10 non-chagasic controls. All neurons were counted in ten en-echelon sections. Neuron hypertrophy only occurred in the group with megacolon, and the average increase in diameter was 69.3%. This could generate an error factor in the neuron count by increasing the probability of neurons being seen in a greater number of histological sections. The original result of the neuron count gave medians of 1264, 1961, and 2665 in the groups of chagasic patients with megacolon, without megacolon, and in the control, respectively. The denervation was greater than 55% in only seven megacolon cases (41.2%). After applying a correction factor, the median in the group with megacolon was 746, and the denervation was greater than 55% in 13 cases (76.5%). This occurrence demonstrates the need to apply a correction factor when the neuron count in chagasic megacolon is being evaluated and in the other pathologies where neuron hypertrophy may be found.

Second recorded case of human infection by Echinococcus oligarthrus.

The paper reviews a previously published case of hydatid disease in the human heart of a Brazilian person who died of tetanus. Based on present knowledge about the distinguishing characteristics of Echinococcus granulosus, E. vogeli, and E. oligarthrus, it was recognized that the infection was due to E. oligarthrus, mainly based the morphologic features of the hooklets of the protoscolex. This is the second human infection due to E. oligarthrus and the first showing wall features of cysts. Therefore, some human infections of polycystic hydatid disease observed outside the range of the bush dog, the only definitive host of E. vogeli (Panama to Northern Argentina), may be due to E. oligarthrus rather than to E. vogeli.

Expression of major histocompatibility complex antigens and adhesion molecules in hearts of patients with chronic Chagas' disease.

We have previously reported that heart lesions in patients with chronic cardiac Chagas' disease are composed predominantly of granzyme A+, cytolytic CD8+ T lymphocytes. We now pursue this study in the immunopathology of chronic chagasic cardiomyopathy by investigation of the expression of HLA antigens, and adhesion molecules in the hearts of seven chagasic patients with cardiac disease, two asymptomatic chagasic patients, and seven normal controls. Comparative immunohistochemical analyses show that HLA-ABC antigen expression is enhanced on the myocardial cells of chagasic patients with chronic cardiomyopathy, suggesting a possible role for these cells as targets for the CD8+ cytolytic lymphocytes dominant in these lesions. The HLA-DR antigens are not observed on myocardial cells, but are consistently upregulated on the endothelial cells in the hearts of patients with chronic chagasic cardiomyopathy. Intercellular adhesion molecule is expressed by endothelial cells of both chagasic and nonchagasic individuals, but E-selectin was detected only on vessels of hearts from chagasic patients who had chronic cardiomyopathy. Most of the lymphocytes in these lesions express lymphocyte function antigen-1 (LFA-1), CD44, and very late antigen-4, and a few display weak expression of LFA-3. We propose that the expression of these adhesion molecules and major histocompatibility complex antigens by endothelial cells, myocardial cells, and lymphoid cells in these lesions contribute to the pathogenesis of chronic chagasic cardiomyopathy.

Post-mortem diagnosis of chronic Chagas's disease comparative evaluation of three serological tests on pericardial fluid.

In an attempt to improve the post-mortem diagnosis of Chagas's disease the authors performed haemagglutination tests (HAT), fluorescent Trypanosoma cruzi antibody tests (FAT), and complement fixation tests (CFT) on the pericardial fluid obtained at autopsy of 50 individuals with Chagas's heart disease, and 93 patients in whom this disease was not thought to be present. The results demonstrate that all three tests are efficient for the post-mortem diagnosis of Chagas's disease but suggest that their combined use would detect more cases than would one isolated reaction only.

Total and specific anti-Trypanosoma cruzi immunoglobulin E in pericardial fluid samples from patients with chronic Chagas disease.

Levels of total and specific anti-Trypanosoma cruzi immunoglobulin E (IgE) were determined by immunoenzymatic assay among 101 samples of pericardial fluid from patients who had died in one trypanosomiasis endemic area in central Brazil. These samples were divided into 6 groups. Group I, 17 samples from patients with the cardiac form of Chagas disease; group II, 11 samples from patients with the digestive form of Chagas disease, presenting megaoesophagus and/or megacolon; group III, 41 samples from patients with the indeterminate form of Chagas disease; group IV, 4 samples from patients with both cardiac and digestive forms of Chagas disease; group V, 5 samples from patients who suddenly died and were seropositive for T. cruzi antibodies; group VI, 23 samples, used as a control group, which came from patients seronegative for T. cruzi antibodies. Significantly high levels of total IgE were observed in groups I, II, III, IV and V when compared with group VI (mean concentrations 708-1157 iu/mL compared with 394 iu/mL). In groups I-V, 32 samples (41%) had specific anti-T. cruzi IgE antibodies. The individual percentage positivity rates in these groups were 64.7% (group I), 45.4% (group II), 34.1% (group III), nil (group IV), and 40.0% (group V). A significant correlation between total IgE and specific anti-T. cruzi IgE was observed only in the samples from patients with the cardiac form of Chagas disease (group I).

[Pathological anatomy of chagasic megaesophagus]. / Contribuição ao estudo da anatomia patológica do megaesôfago chagásico.

Systematized study was made in 56 esophagi of chronic chagasics (17 with and 39 without megas) aiming to: 1) to evaluate the esophageal caliber and thickness ranges; 2) analyse qualitative and quantitatively, the myenteric plexuses, trying to evaluate the relation of their lesions and the development of megaesophagus (ME); 3) study the lesions of the muscularis propria to verify if they contribute or not to the beginning of the process; 4) search for T. cruzi and its eventual relationship with the inflammation; 5) identify the principal mucosal alterations. It was confirmed that the severest lesions were found in the muscularis propria and in the plexures of Auerbach ganglia. In the former, the main alterations were myositis and fibrosis. The myentric plexuses showed inflammation and neuronal depopulation when compared with non-mega chagasic esophagi and even more when compared with the controls. On the other hand, there were normal caliber esophagi with severe denervation. It is possible that several factors may lead to the esophagopathy, especially to the ME. The search for T. cruzi was found positive in four out of eight esophagi with mega and in none of eight chagasic esophagi without mega. Mucosal and submucosal lesions were unremarkable and do not seem to be involved with the development of the process.

Neuronal counting and parasympathetic dysfunction in the hearts of chronically Trypanosoma cruzi-infected rats.

Ten male Wistar rats, chronically infected with Colombian, São Felipe (12SF) and Y strains of Trypanosoma cruzi and ten non-infected control animals were submitted to the bradycardia responsiveness test, an assessment of heart parasympathetic function, after phenylephrine injection. Six chagasic animals showed heart parasympathetic dysfunction characterized by reduction in the index of bradycardia baroreflex responsiveness, as compared with the control group. Microscopic examination of the atrial heart ganglia of chagasic rats showed ganglionitis, but no statistically significant reduction in the number of neurons.

[On the reversal of schistosomiasis hepatic fibrosis after specific therapy. Histopathologic study]. / Sobrea reversão da fibrose hepática esquistossomótica após terapêutica específica. Estudo histológico.

Surgical liver biopsies of patients of both sexes, between 18 and 72 years old, with the compensated hepatoesplenic form of schistosomiasis mansoni, previously treated with oxaminique (Mansil) were studied by histological and immunohistochemical methods. Although the search for parasites and/or granulomas was negative in all specimen studied, the portal fibrosis remained.

[Histopathological and immunohistochemical characteristics of cutaneous and oral mucosa lesions in disseminated histoplasmosis associated with acquired immunodeficiency syndrome (AIDS)]. / Características histopatológicas e imunohistoquímicas das lesões cutâneas e da mucosa oral na histoplasmose disseminada de portadores da síndrome da imunodeficiência adquirida (AIDS).

Biopsy specimens of the skin and oral mucosa from twenty-five patients bearing the disseminated form of histoplasmosis (H. capsulatum) associated with AIDS (acquired immunodeficiency syndrome) were studied by histologic and immunohistochemistry techniques. Histologically, the skin lesions showed four different patterns: diffuse macrophage, granulomatous, vasculitic with leukocytoclastic and scarce inflammatory reaction. The cell markers for macrophages, lymphocytes B and T and H. capsulatum revealed CD68, UCHL-1 and L26 associated with variable amounts of fungi.

[Sudden death caused by the spontaneous rupture of the right ventricle in a woman with chronic Chagas disease]. / Morte súbita por ruptura espontânea do ventrículo direito em mulher chagásica crônica.

We report a case of sudden death from hemopericardium consequent to spontaneous rupture of the right ventricle in a 49-year-old chronic chagasic woman. To our knowledge, this is the third reported case of spontaneous cardiac rupture with chagasic cardiomyopathy. In our case we believe that the thinning of the anterior right ventricular wall, its large ray curvature and the increased ventricular pressure were factors favoring the rupture. There was no infarction and the chronic cardiopathy was significant. It caused the thinning of the rupture region through chronic myocarditis.

[Human chronic chagasic myocarditis: quantitative study of CD4+ and CD8+ lymphocytes in inflammatory exudates]. / Miocardite chagásica crônica humana: estudo quantitativo dos linfócitos CD4+ e dos CD8+ no exsudato inflamatório.

Myocardial exsudate CD4+ and CD8+ lymphocytes were counted in transmural left ventricular free wall frozen sections taken from 10 necropsied chronic cardiac chagasic patients. The cells were labeled with monoclonal antibodies using a streptavidin-biotin technique. We counted: 1) lymphocytes in the total exsudate (LTE) and, separately, 2) the lymphocytes touching or very near to myocells (LTVNM). Lymphocytes were considered very near whenever their own nuclear shortest nuclear diameter was larger than their distance from myocells. CD8+ lymphocytes were more numerous than CD4+ lymphocytes, especially among the LTVNM. The LTE CD4/CD8 ratio was 0.37 +/- 0.20, but the LTVNM CD4/CD8 ratio was smaller (0.23 +/- 0.11). Among the LTE, 34 +/- 11% of CD8+ (against 24 +/- 12% of CD4+) were LTVNM. All these differences were statistically significant. Both subtypes of T-lymphocytes were found to have an intimate relationship with both ruptured and unruptured myocells, and parasites were not seen. These findings are in accordance with the idea that the myocardial cell lesions in the cardiac form of human Chagas' disease are mediated mainly by T-cytotoxic lymphocytes.

[Cardiac neuronal depopulation in hamsters (Mesocricetus auratus) chronically infected with Trypanosoma cruzi]. / Despopulação neuronal cardíaca em hamsters (Mesocricetus auratus) cronicamente infectados com o Trypanosoma cruzi.

The aim of this study was to obtain an experimental animal model of destruction of cardiac neurons in order to investigate the behavior of the cardiac nervous system of hamsters chronically infected with Trypanosoma cruzi. We counted the neuronal cells of the cardiac autonomic nervous plexus in hamsters inoculated with 35,000 blood forms of three different T. cruzi strains and killed 5, 8 and 10 months after infection. We showed for the first time severe neuronal destruction in an experimental animal model with characteristics similar to those observed in human Chagas'disease.

The hamster (Mesocricetus auratus) as experimental model in Chagas' disease: parasitological and histopathological studies in acute and chronic phases of Trypanosoma cruzi infection.

This research characterizes the acute and chronic phases of Chagas' disease in hamster through parasitological and histopathological studies. The acute phase was achieved with 44 young hamsters injected intraperitoneally with 100,000 blood trypomastigotes of Benedito and Y strains of T. cruzi. The chronic phase was induced in 46 hamsters injected intraperitoneally with 35,000 trypomastigotes of Vicentia, Benedito and Y strains. Animals were sacrificed at regular intervals of 24 hours of acute phase and from the 3rd to the 10th month of infection of chronic phase. In the acute phase, parasites were easily recovered from all animals and there was an inflammatory reaction characterized by mononuclear and polymorphous leukocyte infiltration of variable degree in the majority of tissues and organs, specially in the connective loose and fatty tissues, smooth muscle myocardium and skeletal muscle. In the chronic phase the lesions occurred in the same tissues and organs, but the inflammatory response was less severe and characterized by mononuclear infiltration mainly with focal or zonal fibrosis in the myocardium. In 50% of infected animals parasites were found in myocardium and recovered from pericardic, peritoneal and ascitic fluids in some animals. Signs of heart failure, sudden death and enlargement of bowel were observed regularly. We concluded that the hamster is an useful model for Chagas' disease studies.

[A quantitative analysis of the mastocytes and eosinophilic granulocytes in the myocardium of Wistar rats chronically infected by Trypanosoma cruzi. A contribution to the knowledge of myocardial fibrosis]. / Análise quantitativa de mastócitos e de granulócitos eosinófilos no miocárdio de ratos Wistar cronicamente infectados pelo Trypanosoma cruzi. Contribuição ao conhecimento da fibrose miocárdia.

We did mast cell and eosinophil granulocyte counts in the myocardium of forty chronic chagasic Wistar albino rats. We used 10 controls rats and 30 animals with late-stage (8th month) infection of São Felipe, Y and Colombian Trypanosoma cruzi strains, with variable degree of chronic myocarditis. We found chronic fibrosing myocarditis (fibrosis) in 40% of the infected animals. It was detected increased mast cell count in the chagasic rats associated with infection and not related with myocardial fibrosis. There was no increase in the eosinophil counts.

[Prevalence of visceromegalies in necropsies carried out in Triângulo Mineiro from 1954 to 1988]. / Prevalência de megas em necrópsias realizadas no Triângulo Mineiro no período de 1954 a 1988.

One thousand seven hundred and eight chronic chagasic post-mortem examinations studied from a total of 4690 autopsies performed at our Institution. Two hundred and seventy-three chagasic had megas. Megacolon was the most frequent, followed by megaesophagus. Megacolon associated with megaesophagus was the third most common finding. Our data are discussed and compared with the literature. Megacolon and megaesophagus were more prevalent in man, as shown by other workers. Higher parasitemia perhaps could explain this finding.

[Toxoplasmic and chagasic meningoencephalitis in patients with human immunodeficiency virus infection: anatomopathologic and tomographic differential diagnosis]. / Meningoencefalites toxoplásmica e chagásica em pacientes com infecção pelo vírus da imunodeficiência humana: diagnóstico diferencial anatomopatológico e tomográfico.

Twenty-two HIV+ patients with encephalitis were studied. Of these, 7 had meningoencephalitis due to Toxoplasma gondii (MT) and 15 due to Trypanosoma cruzi (MC). Pathologic and computerized axial tomography (CAT) changes were compared. We found that focal necrotizing encephalitis due to Toxoplasma involved the cerebral cortex and the basal ganglia, whereas lesions due to Trypanosoma cruzi were centered in the white matter, sometimes extending into the cortex. Hemorrhages, myelin lesions and organisms were more pronounced in chagasic than in toxoplasmic encephalitis. These findings are consistent with the literature reviewed.

[Intracardial autonomous nervous system in a fatal case of acute Chagas disease]. / Sistema nervoso autônomo intracardíaco em caso humano fatal de doença de Chagas aguda.

An analysis of the intracardiac autonomic nervous system (ICANS) has been made in 150 histological sections obtained from atrial fragments of a 74 year-old man who died of cardiac failure, as a consequence of acute Chagas' disease (ACD), probably acquired via digestive tract. Small quantities of mononuclear infiltrate around ganglia and/or nerve branches without significant morphologic alterations of the neurons were found in 10 slides; another slide showed ganglionitis and periganglionitis of moderate intensity associated to neuronal alterations. Focal epicarditis, usually of slight degree, was observed in all slides. The findings suggest: a) that the inflammation of ganglia and fibers of the ICANS in the ACD occurs at least in part by expansion from adjacent epicarditis; b) that even in the fatal cases of the trypanosomiasis cruzi the pathologic lesions of the ICANS may be slight.

Chagasic meningoencephalitis in the immunodeficient.

Based on their own experience and on the literature, the authors compare the brain pathology due to HIV+ associated Trypanosoma cruzi reactivated infection to that described for the natural history of the Chagas' disease (CD). The peculiar focal necrotizing chagasic meningoencephalitis (MECNF) which appears only in immunedeficient chagasics, especially when the deficiency is due HIV is a safe criterion for reactivation of CD. MECNF morphologic findings are unlike to those found either for some cases of acute phase CD or for chronic nervous form of CD.

[Megas and cancer. Cancer of the large intestine in chagasic patients with megacolon]. / Megas e câncer. Câncer de intestino grosso em chagásicos com megacólon.

This is a review of 4.690 necropsies and 24.209 surgical pathology specimens describing the association between megacolon chagasic and malignant tumors of the large bowel. The prevalence of malignant tumors of the large bowel was not higher in megacolon.