[Comparison of parasitology of the central vein of the adrenal gland and the other tissues in chronic chagas disease]

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.

Influência da parasitemia na evolução da doença de Chagas crônica

Estudou-se clínica e parasitologicamente, durante 13 anos, 190 indivíduos com infecção chagásica objetivando investigar a relação entre parasitemia e a evolução da doença de Chagas crônica. Comparou-se a parasitemia de 56 indivíduos xenopositivos e 134 xenonegativos, em 1988/91 com a evolução clínica encontrado-se 22 (39,3%) e 50 (37,3%), respectivamente, com evolução progressiva. Estratificou-se a parasitemia em 1988/91, em alta, média e baixa e a correlação clínica mostrou que 5 (62,5%), 10 (41,7%) e 57 (36.1%) indivíduos, respectivamente, apresentaram evolução progressiva, sem diferença estatística significante, (p>0,05). No período de 1976/91, houve 20 pacientes com parasitemia constante e 59 sem parasitemia, observando-se evolução progressiva em 6 (30%) e 17 (28,8%), respectivamente. Houve seis pacientes com alta parasitemia e, 59 sem parasitemia, verificado-se que 3 (50%) e 17 (28,8%), respectivamente, apresentaram evolução progressiva, sem diferença estatística significante, (p>0,05). As médias das idades daqueles com alta, média e baixa parasitemias foram 39,6; 45,3 e 41,5 anos, respectivamente, (p>0,05). As médias das idades dos pacientes com evolução progressiva, inalterada e regressiva foram respectivamente, 46,4; 39,8 e 32,6 anos, com diferença estatística significante entre aqueles com evolução progressiva e regressiva, (p<0,05). Sugere-se que a alta parasitemia não influenciou na evolução da doença crônica.

O plexo pampiniforme na fase crônica da doença de Chagas humana: avaliação histológica

Pesquisou-se a ocorrência, na parede das veias do plexo pampiniforme de chagásicos crônicos, de acúmulos intracelulares de Trypanosoma cruzi e sinais inflamatórios (flebite). Para tal fim, colheram-se, à necropsia, 23 pares de funículos espermáticos, epidídimos e testículos, sendo 17 de chagásicos crônicos e 6 de controles (não chagásicos). Em cada caso, foram feitos múltiplos cortes das gônadas e dos vasos; fez-se pesquisa de T. cruzi por imuno-histoquímica nos funículos espermáticos de todos os casos. Não se observaram parasitos nas paredes vasculares. Notou-se flebite crônica inespecífica, focal e discreta, em cinco chagásicos (bilateral em três pacientes) e dois controles; havia infiltração mononuclear discreta do interstício funicular em treze chagásicos e cinco controles. A análise estatística dos resultados (chi2) não revelou diferenças significativas. Conclui-se que o ambiente hormonal devido à testosterona não parece favorecer a infecção da parede dos vasos gonadais por Trypanosoma cruzi, embora, segundo a literatura, o referido hormônio pareça ter ações imunodepressoras.

[The behavior of Trypanosoma cruzi parasitemia in chronic chagasics over 13 years]

The parasitemia of 202 chronic chagasics was studied for approximately 13 years by repeated conventional xenodiagnoses. Mean patient age was 41.1 years. They lived in an endemic area; 124 were females and 78 were males. It was seen that the level of parasitemia oscillated. It went up in 14 individuals, went down in 42 and stayed at the same level in 146. In general the parasitemia was reduced. The percentage of xenopositive chagasics, which was 37.6%, 48.5%, and 51% in the first, second and third xenodiagnosis, respectively, in 1976/78, changed to 30.2% in 1988/91 (p = 0.00003). The percentage of positive pools, which was 15.2%, 20.9%, 20.8% in the first, second and third xenodiagnosis, respectively, in 1976/78, changed to 10.4% in 1988/91, (p = 0.00000001). There were 62 patients whose xenodiagnoses were all negative and 23 whose exams were all positive. The percentage of chagasics with high, medium and low parasitemia, which in 1976/78 was 9.4%, 20.8% and 69.8%, respectively, changed to 4.4%, 12.9% and 82.7%, respectively, in 1988/91.

[The influence of corticoids, in Chronic Chagas disease, administered in virtue of associated disorders]

Patients with chronic Chagas' disease and simultaneous medical problems treated with corticosteroid were studied in order to evaluate steroid influence on chronic Trypanosoma cruzi infection. Parasitological assessment, radiological and electrocardiographic studies as well as non specific tests were performed in patients and in a control group that included chronic infected patients not treated with steroid. Xenodiagnosis showed a clear increase in T. cruzi parasitemia, related to the corticosteroid dosage, without clinical manifestations during the study follow-up period.

Possible role of an adrenal parasite reservoir in the pathogenesis of chronic Trypanosoma cruzi myocarditis

The possible contribution of parasitism of the central vein of the adrenal gland (CVAG) to chronic Trypanosoma cruzi myocarditis was assayed by comparing the occurrence of nests of amastigotes in the left ventricular myocardium (LVM) and determining the number and extent of areas of focal leucocyte exudate (FLE) in Chagas disease patients with and without CVAG parasitism. The frequency of occurrence of T. cruzi nests in the LVM, as well as the FLE number and area, were greater among patients with CVAG parasitism. We therefore suggest that CVAG parasitism plays a role in the onset and intensity of chronic T. cruzi myocarditis.