Immune response, nitric oxide, autonomic dysfunction and stroke: a puzzling linkage on Trypanosoma cruzi infection.

Trypanosoma cruzi (T. cruzi) is a tissue parasite causing American trypanosomiasis or Chagas' disease (ChD) affecting, mostly, the cardiovascular and gastrointestinal systems. We have recently found that people infected by T. cruzi are also more prone to developing ischemic strokes than the general population, even without heart complications; the pathomechanism of it is not yet well understood. However, after infection occurs, immune response induces endothelial dysfunction due to an endothelial nitric oxide synthase (eNOS) inhibition and increased activity of inducible nitric oxide synthase (iNOS). These factors are active in inducing vasoconstriction and cerebral microvascular spasms, leading to ischemic stroke. In addition, patients with ChD, regardless of cardiopathy, also have autonomic dysfunction, all of which may enhance the risk of developing ischemic stroke. Moreover, the possibility that these neuroimmunomodulatory pathways are disturbed in patients with other types of stroke seems possible, and is worthy of investigation.