The anti-oxidant defence response in individuals with the indeterminate form of Chagas disease (American trypanosomiasis)

Abstract

In previous studies in animal models, Trypanosoma cruzi-induced oxidative stress and damage have sometimes been controlled by the host's anti-oxidant defence responses. The role of the anti-oxidant defence responses, such as the activities of the anti-oxidant enzymes glutathione peroxidase (GPx) and superoxide dismutase (SOD), in protection against inflammation and damage have now been investigated in humans infected with T. cruzi. The subjects were 32 asymptomatic but seropositive individuals with the indeterminate form of Chagas disease, 18 symptomatic and seropositive patients with the chronic disease, and 50 seronegative and apparently healthy controls. The inflammatory process was explored using serum concentrations of tumour necrosis factor (TNF) and NO. The serum concentrations of GPx in the patients in the indeterminate phase of infection were similar to those in the controls but much higher than those in the chronic cases (P=0.001). The serum concentrations of SOD in the patients in the indeterminate phase of infection were not only significantly higher than those in the cases of chronic Chagas disease (P=0.0004) but also significantly higher than those in the controls (P<0.001). The seropositive subjects had significantly higher serum concentrations of TNF and NO than the controls (P<0.01 for each) and the cases of chronic Chagas disease had significantly higher serum concentrations of TNF and NO than the subjects with the indeterminate form of the disease (P<0.01 for each). It therefore appears that the host's anti-oxidant defence responses (at least in terms of elevated concentrations of SOD) may inhibit inflammation during the indeterminate phase of Chagas disease.

Immunological imbalance between IFN-³ and IL-10 levels in the sera of patients with the cardiac form of Chagas disease

“…IL-2, IFN-γ, and TNF-α production were similar in all groups of chagasic patients with different forms of the disease (Ward et al 1999). These results were confirmed by other studies, which also showed that, although the levels of TNF-α and NO were higher in sera from chagasic patients, compared to non-chagasic individuals, no difference was observed between asymptomatic and symptomatic chagasic patients (Perez-Fuentes et al 2008). IFN-γ levels were similar in the sera of asymptomatic individuals and CARD patients that presented the form of the disease (Ribeirao et al 2000).…”

Chronic Chagas disease: from basics to laboratory medicine

“…In addition, lower blood activities of antioxidant enzymes (total superoxide dismutase, manganese superoxide dismutase and glutathione peroxidase) and a lower level of the non-enzymatic antioxidant glutathione have been found. A reduced antioxidant defense was also found in other studies [164,165] . A deficiency in selenium was also found in chronic Chagas patients, especially in those with progressed cardiomyopathy [166] .…”

Chronic Chagas’ heart disease: a disease on its way to becoming a worldwide health problem: epidemiology, etiopathology, treatment, pathogenesis and laboratory medicine

“…Additionally, in this study, the lower blood activities of antioxidant enzymes (total superoxide dismutase, manganese superoxide dismutase and glutathione peroxidase) and non-enzymatic antioxidant glutathione were found. Decreased antioxidant defense was also demonstrated in other studies [144,145]. A selenium deficiency was found in chronic Chagas' patients, especially in those with progressed cardiomyopathy [146].…”