Evaluation of Cardiac IL-11 and IL-11Rα Expression During T. cruzi Infection.

Chagas disease (CD), caused by Trypanosoma cruzi, leads to cardiomyopathy in approximately 20-30% of infected individuals. Interleukin-11 (IL-11) has been implicated in cardiac fibrosis, although its immunological role in this context remains unclear. This study investigated the temporal dynamics of IL-11 and its receptor, IL-11Rα, expression in the hearts of C57BL/6 mice infected with 1,000 trypomastigote forms of the Y or Colombian strains of T. cruzi. Mice were euthanized at 5, 15, 30, 60, and 120 days post-infection (dpi). Survival, parasitemia, and body and heart weights were monitored. Cardiac tissue was analyzed for parasite nests, myocarditis, collagen deposition, and expression of the IL-11 receptor alpha (IL-11Rα). Cytokine profiles were evaluated by ELISA and Cytometric Bead Array. Histopathological analysis revealed more intense myocarditis, parasite load, and collagen deposition in mice infected with the Colombian strain. Both strains induced IFN-γ, TNF-α, and IL-6 in cardiac tissue; however, IL-10, IL-4, and IL-17 were detected only in the Y strain, indicating a more balanced immune response. Despite the absence of significant IL-11 upregulation in either infection, IL-11Rα expression was progressively increased over time and positively correlated with collagen deposition. These findings suggest that IL-11Rα may play a role in cardiac remodeling and fibrosis independently of IL-11 upregulation. The results reinforce the importance of T. cruzi strain variability in disease outcome and highlight the IL-11/IL-11Rα axis as a potential target for further investigation in Chagas cardiomyopathy.