Thyroid hormones influence on Trypanosoma cruzi in vitro and in vivo infection

To evaluate the influence of thyroid hormones (THs) on Chagas disease (CD) to improve understanding of host susceptibility factors.

In vitro assays included growth curves in liver infusion tryptose medium to assess the effect of TH on Trypanosoma cruzi metabolism, phagocytosis assays in macrophages sensitized with TH, and enzyme-linked immunosorbent assay (ELISA) tests to determine anti-T. cruzi antibody levels. In vivo experiments were conducted on three groups of BALB/c mice: hypothyroid (induced by methimazole), hyperthyroid (induced by levothyroxine sodium), and euthyroid (control). T. cruzi cardiotropic NINOA strain (TDU-I group) was used. Parasitemia, mortality, and histopathology were evaluated.

No significant changes were observed in parasite growth kinetics in vitro. However, macrophages treated with TH exhibited increased phagocytic capacity. ELISA results showed higher levels of anti-T. cruzi antibodies in TH-treated hosts. In vivo, parasitemia varied among groups, with the highest mortality and tissue damage observed in hypothyroid mice.

TH modulates the immune response, disease progression, and outcomes in CD. These insights suggest that thyroid status evaluation could be a key component for personalized clinical management.