The role of fat on cardiomyopathy outcome in mouse models of chronic Trypanosoma cruzi infection.

The underlying pathogenic mechanisms of cardiomyopathy in Chagas disease are still unsolved. In order to better clarify the role of fat on the evolution of cardiomyopathy, the present study employed three murine models of chronic Trypanosoma cruzi infection: (1) aP2-RIDα/ß transgenic mice (RID mice; an adipose tissue model which express a gain-of-function potent anti-inflammatory activity), (2) allograft inflammatory factor-1 knockout mice (Aif1-/-), and (3) a Swiss outbred mice. RID mice and non-transgenic mice (wild type, WT) were infected with blood trypomastigotes of Brazil strain. During the acute stage of infection, RID mice had lower parasitemia, lower heart inflammation, and a decrease in the relative distribution of parasite load from cardiac muscle tissue toward epididymal fat. Nevertheless, comparable profiles of myocardial inflammatory infiltrates and relative distribution of parasite load were observed among RID and WT at the chronic stage of infection. Aif1-/- and Aif1+/+ mice were infected with bloodstream trypomastigotes of Tulahuen strain and fed with high-fat diet (HFD) or regular diet (RD). Interestingly, Aif1+/+ HFD infected mice showed the highest mortality. Swiss mice infected with blood trypomastigotes of Berenice-78 strain on a HFD had higher levels of TNFα and more inflammation in their heart tissue than infected mice fed a RD. These various murine models implicate adipocytes in the pathogenesis of chronic Chagas disease and suggest that HFD can lead to a significant increase in the severity of parasite-induced chronic cardiac damage. Furthermore, these data implicate adipocyte TLR4-, TNFα-, and IL-1ß-mediated signaling in pro-inflammatory pathways and Aif-1 gene expression in the development of chronic Chagas disease.

Correction to: The role of fat on cardiomyopathy outcome in mouse models of chronic Trypanosoma cruzi infection.

The authors regret that Philipp E Scherer's name was spelt incorrectly in the author list. The name of the author is now corrected above.

Alterations in pancreatic ß cell function and Trypanosoma cruzi infection: evidence from human and animal studies.

The parasite Trypanosoma cruzi causes a persistent infection, Chagas disease, affecting millions of persons in endemic areas of Latin America. As a result of immigration, this disease has now been diagnosed in non-endemic areas worldwide. Although, the heart and gastrointestinal tract are the most studied, the insulin-secreting ß cell of the endocrine pancreas is also a target of infection. In this review, we summarize available clinical and laboratory evidence to determine whether T. cruzi-infection-mediated changes of ß cell function is likely to contribute to the development of hyperglycemia and diabetes. Our literature survey indicates that T. cruzi infection of humans and of experimental animals relates to altered secretory behavior of ß cells. The mechanistic basis of these observations appears to be a change in stimulus-secretion pathway function rather than the loss of insulin-producing ß cells. Whether this attenuated insulin release ultimately contributes to the pathogenesis of diabetes in human Chagas disease, however, remains to be determined. Since the etiologies of diabetes are multifactorial including genetic and lifestyle factors, the use of cell- and animal-based investigations, allowing direct manipulation of these factors, are important tools in testing if reduced insulin secretion has a causal influence on diabetes in the setting of Chagas disease. Long-term clinical investigations will be required to investigate this link in humans.