Trypanosoma cruzi infection in mice significantly reduced transient outward K+ current by approximately 50% and decreased L-type Ca2+ current in right ventricular myocytes.
Does Trypanosoma cruzi infection alter the histological and electrical properties of right ventricular myocytes in a murine model of Chagas disease?
Trypanosoma cruzi infection in mice causes right ventricular myocyte electrical remodeling (prolonged action potential, reduced K+ and Ca2+ currents) associated with parasite persistence and inflammation, providing a mechanistic basis for arrhythmias in Chagas disease.
Absolute Event Rate: 15.1% vs 31.9%
p-value: p=<0.05
Chagas disease, caused by the triatominae Trypanosoma cruzi, is one of the leading causes of heart malfunctioning in Latin America. The cardiac phenotype is observed in 20-30% of infected people 10-40 years after their primary infection. The cardiac complications during Chagas disease range from cardiac arrhythmias to heart failure, with important involvement of the right ventricle. Interestingly, no studies have evaluated the electrical properties of right ventricle myocytes during Chagas disease and correlated them to parasite persistence. Taking advantage of a murine model of Chagas disease, we studied the histological and electrical properties of right ventricle in acute (30 days postinfection dpi) and chronic phases (90 dpi) of infected mice with the Colombian strain of T. cruzi and their correlation to parasite persistence. We observed an increase in collagen deposition and inflammatory infiltrate at both 30 and 90 dpi. Furthermore, using reverse transcriptase polymerase chain reaction, we detected parasites at 90 dpi in right and left ventricles. In addition, we observed action potential prolongation and reduced transient outward K(+) current and L-type Ca(2+) current at 30 and 90 dpi. Taking together, our results demonstrate that T. cruzi infection leads to important modifications in electrical properties associated with inflammatory infiltrate and parasite persistence in mice right ventricle, suggesting a causal role between inflammation, parasite persistence, and altered cardiomyocyte function in Chagas disease. Thus, arrhythmias observed in Chagas disease may be partially related to altered electrical function in right ventricle.
Cruz et al. (2016) studied Chagas disease. Trypanosoma cruzi infection (Colombian strain) vs. Uninfected control mice was evaluated on Transient outward K+ current (Ito) density at +50 mV at 30 days postinfection (pA/pF) (p=<0.05). Trypanosoma cruzi infection in mice significantly reduced transient outward K+ current by approximately 50% and decreased L-type Ca2+ current in right ventricular myocytes.