Myenteric plexus is differentially affected by infection with distinct Trypanosoma cruzi strains in Beagle dogs

Chagasic megaoesophagus and megacolon are characterised by motor abnormalities related to enteric nervous system lesions and their development seems to be related to geographic distribution of distinct Trypanosoma cruzi subpopulations. Beagle dogs were infected with Y or Berenice-78 (Be-78) T. cruzi strains and necropsied during the acute or chronic phase of experimental disease for post mortem histopathological evaluation of the oesophagus and colon. Both strains infected the oesophagus and colon and caused an inflammatory response during the acute phase. In the chronic phase, inflammatory process was observed exclusively in the Be-78 infected animals, possibly due to a parasitism persistent only in this group. Myenteric denervation occurred during the acute phase of infection for both strains, but persisted chronically only in Be-78 infected animals. Glial cell involvement occurred earlier in animals infected with the Y strain, while animals infected with the Be-78 strain showed reduced glial fibrillary acidic protein immunoreactive area of enteric glial cells in the chronic phase. These results suggest that although both strains cause lesions in the digestive tract, the Y strain is associated with early control of the lesion, while the Be-78 strain results in progressive gut lesions in this model.

Anthelminthic treatment raises plasma iron levels but does not decrease the acute-phase response in Jakarta school children.

The study was conducted to investigate the impact of intestinal helminthiasis and treatment on iron status and acute phase response (APR) among urban Indonesian primary school children, aged 8-11 years old. The prevalence of helminthiasis among these children was; Ascaris lumbricoides, 81.6%; Trichuris trichiura, 88.3%; and mixed infection of A. lumbricoides and T. trichiura, 70.0%. Of 120 children enrolled in the investigation, 59 received a single 400 mg dose of albendazole, and 61 received a placebo. Ten days following treatment, the prevalence of ascariasis and trichuriasis in the treatment group diminished to 0% and 27%, respectively, and in the placebo group to 63.9% and 68.9%. Plasma iron, hemoglobin, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), white blood cell (WBC), interleukin-1 (IL-1), interleukin-6 (IL-6) and tumor necrosis factor (TNF) concentrations were determined prior to the intervention and 10 days after. Plasma iron concentrations and WBC count rose in the treatment group (p=< or =0.05) when compared to baseline status. Increases in hemoglobin concentrations observed in the treatment group 10 days post-treatment were not statistically significant. CRP, IL-1, IL-6 and TNF were found to be within normal limits for both groups both before and after treatment. ESR increased significantly in both treatment and placebo groups when compared the rates measured before treatment. These findings show that treatment with albendazole is associated not only with a decreased worm burden in school children, but also a rise in plasma iron.

Estudo dos níveis plasmáticos de alfa-macroglobulinas durante a fase aguda da infecção por Trypanosoma cruzi / Study of the plasma levels of alpha-macroglobulins during the acute phase of infection for Trypanosoma cruzi

Analisou-se a resposta de fase aguda (RFA) à infecção experimental por T. cruzi, através de estudos dos níveis plasmáticos de uma família de proteínas de fase aguda (PFA), as alfa-macroglobulinas (AM) em diversas cepas de camundongos. As AM são importantes inibidores fisiológicos de proteases, tendo também atividade imunomodulatória. Para a realização deste estudo foi fundamental a elaboração de um método de ELISA de inibição extremamente sensível, permitindo a detecção de AM em pequenos volumes de plasma. O desenvolvimento deste ELISA viabilizou o acompanhamento individualizado de animais controle e infectados e a comparação das respostas de animais resistentes e suscetíveis à infecção. Os resultados obtidos demonstram que as AM são importantes PFA em duas das três cepas de camundongos isogênicos estudadas. Ficou demonstrado ainda que os padrões de síntese de AM durante a fase aguda são diferentes nas diversas cepas estudadas, embora sejam homogêneos entre animais de umamesma cepa. Os resultados indicam que as AM atuam como PFA também em animais geneticamente heterogêneas, embora nestes casos o nível e a cinética de síntese de A2M sejam extremamente variáveis. Não se observou a existência de correlação entre níveis de AM e resistência ou susceptibilidade à fase aguda da infecção por T. cruzi. Resultados preliminares obtidos com pacientes durante a fase aguda da infecção por T. cruzi demonstraram que as AM atuam como PFA também na doença de Chagas e que a síntese destas proteínas em humanos apresenta uma heterogeneidade comparável àquela sugerida pelos estudos experimentais. O fato de que as AM têm função imunomodulatória, associado à heterogeneidade de sua síntese durante a fase aguda da infecção por T. cruzi, confirmam a importância de estudos posteriores abordando o eventual envolvimento das AM nos diversos desenvolvimentos da doença de Chagas em sua fase crônica.

Reaçäo de fase aguda e parasitismo na veia central da supra-renal de chagásicos crônicos / Acute-phase reaction and parasitism in the central adrenal vein in Chagas' disease patients

The systemic reaction to severe trauma and/or infection, acute phase response (APR), are often associated with immunosuppression and reactivation of chronic latent infection. Our main purpose was to verify, in a group of 71 autopsied chronic chagasic with or without APR, the frequency of T. cruzi nests in the central vein of adrenal gland (CVAG). APR, defined by: 1) death secondary to sepsis and/or trauma plus, 2) bleeding stress gastric ulcerations or 3) spleen reactional state or 4) liver steatosis, was observed in 30 chronic chagasic (APR+). Weight, height and body mass index (BMI) were obtained. APR(+) chronic chagasic had worse nutritional status than APR(-) ones: weight = 49.0 vs 54.5 kg; BMI = 17.5 vs 20.6 kg/m2 (median p < 0.05). CVAG T. cruzi nests frequency were similar (43.3 per cent and 43.9 per cent , respectively) between both Groups. We conclude that APR(+) chronic chagasic had worse nutritional status than APR(-) ones, and that APR development did not change the CVAG T. cruzi nests frequency