Vasoactive intestinal peptide degradation might influence Interleukin-17 expression in cardiac chagasic patients

The vasoactive intestinal peptide (VIP) expression is lower in cardiac chagasic patients and is related to worse cardiac function. The reduction of VIP in patients with Chagas disease may be a result of its enhanced degradation. To test this hypothesis, the tryptase and chymase expression was evaluated. We also related VIP levels with interleukin-17 (IL-17) expression since VIP may modulate IL-17 production. Plasma levels of chymase were higher in chagasic patients. Conversely, VIP/chymase and VIP/tryptase ratios were lower in chagasic patients when compared to non-infected individuals. Besides, the VIP/chymase ratio was lower in chagasic cardiac patients in comparison with the indeterminate group. A positive correlation between tryptase and chymase levels was observed in chagasic cardiac patients. In relation to IL-17, we observed a higher expression of this cytokine in the cardiac form of the disease than in the indeterminate form. IL-17/VIP ratio was higher in the cardiac form in comparison with non-infected or indeterminate form. These results suggest that the low levels of VIP observed in chagasic patients could be due to an increased production of chymase and/or to the additive effect of the interaction between chymase and tryptase in the cardiac form. Moreover, the decreased VIP expression may contribute to the increase of IL-17 in chagasic cardiac patients.