Neuroregulação e imunoregulação no megacólon chagásico: avaliação da expressão de neurotrofinas, serotonina e concentração de mastócitos

Abstract

Chaga’s disease is considered a public health problem because it is a serious parasitic disease that still affects about 6 million people worldwide. Chagasic megacolon is one of the most serious manifestations of the disease, characterized by intestinal constipation, dilatation of the sigmoid colon and rectum. The histological analysis of the mega chagasic shows lesions of the enteric nervous system, associated with a large reduction in the number of neurons, caused mainly by an inflammatory process. Previous data suggest that the expression of mast cells and serotonin could be involved in the control of intestinal homeostasis, avoiding the development of the chagasic megacolon. In addition, some substances, such as neurotrophins, may restrict levels of neuronal destruction, as has been demonstrated in other neurodegenerative diseases. This study aimed to characterize the expression neurotrophins, serotonin and mast cells in chagasic patients with and without megacolon and to evaluate the relationship between mast cell concentration, serotonin and megacolon development. Colon samples were used from chagasic patients whit and without megacolon and non-infected individuals, who were submitted to immunohistochemistry after preparation. Our results demonstrated that chagasic patients without megacolon present a high amount of serotonin and few mast cells, while mega chagasic patients presented a large amount of mast cells and low serotonin expression. As for neurotrophins, our data indicate that enteroglial cells are the main source of neurotrophins. Patients with megacolon had a high expression of all the neurotrophins analyzed, when compared to nonmega chagasic patients and uninfected individuals. Thus, we suggest that high neurotrophin and serotonin expression may confer neuroprotection to the enteric nervous system during the installation of the chagasic megacolon.