Alterations in pancreatic β 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 β 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 β 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 β cells. The mechanistic basis of these observations appears to be a change in stimulus-secretion pathway function rather than the loss of insulin-producing β 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.