EFFECTS OF CHAGASIC PATIENT'S SERA ON HUMAN INDUCED PLURIPOTENT STEM CELL-DERIVED CARDIOMYOCYTES

Abstract

<h3>Background</h3> Chagas disease is an infectious disease caused by the protozoan Trypanosoma cruzi and can lead to cardiac dysfunction characterized by arrhythmias and heart failure. The presence of circulating autoantibodies capable of recognizing G-protein coupled receptors (GPCR) and activating β-adrenergic and muscarinic receptors has been proposed as an interactive and relevant pathophysiological factor in the development of the disease. However, the interaction of the sera from chronic chagasic patients with human cardiomyocytes has never been tested. This study investigated if chronic chagasic sera previously shown to activate β-adrenergic and muscarinic receptors in rodent and rabbit hearts could also activate these receptors in human cardiomyocytes. <h3>Methods</h3> An induced pluripotent stem cell (iPS) line derived from a healthy donor, previously generated, and characterized in our laboratory, was differentiated into cardiomyocytes (CM-iPS) and their electrophysiology was characterized by Multielectrode Array (MEA) system. We evaluated the effects of an anti-β-adrenergic (Aβ82) and an anti-muscarinic serum (M32) on spontaneous beat rate (BR), field potential amplitude (FPA), and field potential duration (FPD). To minimize the effect of BR on FPD, FPD was corrected (FPDc) using an adaptation of the Bazett equation (FPDc = FPD/√BP), where BP is the interval between spontaneous beats. During recordings, CM-iPS were continuously perfused with Tyrode solution containing or not chagasic sera from patients diluted at 1:100 (v:v). <h3>Results</h3> Sera Aβ-82 induced an increase in BR (16,90±4,22 bpm to 26,60±5,62 bpm, n=5, <i>p</i>=0.0177), FPD (164,03±6,18 ms to 208,73±9,44 ms, n=5, p<0.001), FPDc (80,18±3,16 ms to 139,29±5,90 ms, n=5, <i>p</i><0.001) and did not significantly alter the FPA in CM-iPS. When perfused in presence of atenolol 10µM, no changes in BR, FPD and FPA were observed. In contrast, perfusion of sera M32 decreased BR (46,33±2,46 bpm to 38,16±3,17bpm, n=4, p=0.0011), FPD (225,48±19,48 ms to 186,78±12,05 ms, n=4, <i>p</i>=0.0137), FPDc (179,61±9,66 ms to 131,72±6,14 ms n=4, <i>p</i><0.001) and FPA (675,64±58,61 µV to 458,25±54,09 µV, n=4, p=0,0009). When in presence of atropine 10µM, no changes in BR, FPD and FPA were observed. <h3>Conclusion</h3> We conclude that antibodies present in chronic chagasic patients‘ sera are capable of modulating GCPR activity in the human heart interacting with β-adrenergic and muscarinic receptors present in human cardiomyocytes.