Expression of inflammatory cytokines and chemokines in the heart tissue of chronic Chagas disease cardiomyopathy patients

Author(s)

Luciana Gabriel Nogueira Barbosa

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina (FM/SBD)
• Defense date: 2008-12-04

Examining board members

Edecio Cunha Neto; Pedro Francisco Giavina Bianchi Junior; Maria de Lourdes Higuchi; Rodrigo Corrêa Oliveira; João Santana da Silva

• Advisor: Edecio Cunha Neto

Abstract

Chronic Chagas disease Cardiomyopathy (CCC) is an inflammatory cardiomyopathy that affects around 30% of individuals infected by the protozoan Trypanosoma cruzi and happens 5-30 years after the infection. In Chronic Chagas disease and CCC, there is a significant production of proinflammatory Th1 cytokines and chemokines even in the absence of ventricular dysfunction. Mononuclear cells inflitrating the heart tissue of CCC patients produce some of these inflammatory cytokines. However, the factors that determine the composition of the inflammatory infiltrate and contribute to the migration, accumulation and distribution of inflammatory cells inside heart tissue in the CCC are still unknown. Considering that CCC has worse prognosis than dilated cardiomyopathy of non-inflammatory etiology, we hypothesized that the production of several inflammatory mediators in situ could be involved in the worse prognosis of CCC. Taking this into consideration, our aim in the present study was to analyze the gene expression of pro-inflammatory/Th1 cytokines, chemokines involved in cell T memory migration and its receptors and chemokines involved in Th1/Th2 lymphocyte migration and its receptors. qRT-PCR and immunofluorescence with confocal microscopy were employed to detect the expression these mediators/receptors in left ventricular free wall samples from end-stage CCC patients, patients with non-inflammatory cardiomyopathy (NIC) and healthy donors, obtained upon transplantation. We observed a significant increase in the expression of pro-inflammatory cytokine IL-18, chemokines CCL3/MIP- 1, CCL4/MIP-1, CCL5/RANTES, CXCL9/Mig, CXCL10/IP-10, CCL17/TARC and CCL19/ELC and its receptors CXCR3, CCR5 and CCR4 in the samples of CCC patients compared to NIC patients and control heart samples. On the other hand, we observed absence of expression or downregulation or of TGF-, Foxp3, IL-4 and IL-13, suggesting the absence of regulatory T cells and functional Th2 cells. In addition, the presence of mononuclear CXCR3+, CCR5+ and CCR4+ cells was observed in myocardium of CCC patients using immunofluorescence with confocal microscopy. The chemokines CCL5/RANTES and CXCL9/Mig were detected in mononuclear cells of inflammatory infiltrates of heart tissue CCC patientes. The differential gene expression observed in this study allowed us to elaborate a global profile of inflammatory mediator production in the myocardium CCC patients. The up-regulated gene expression of IL-18 and chemokines and its receptors in the myocardium CCC patients contribute to the migration and accumulation of CCR5+, CXCR3+ Th1 cells and the correlation observed between these mediators and their receptors suggest a positive feedback contributing to the maintenance and amplification of inflammatory process, possibly in association with another mediators expressed in the myocardium. The intense Th1 inflammatory response with the up-regulated expression of various inflammatory mediators in the myocardium of CCC patients could be enhanced by the absence of Foxp3+ or TGF-+, regulatory T cells and the expression of mediators as IL-18 and CCL21/SLC could play a role in the development of hypertrophy and fibrosis suggesting an additional pathophysiologic role of expression of these mediators in CCC patients. (AU)