Cardiac arrhythmias after renal I/R depend on IL-1ß.

AIMS: Cardiac arrhythmias are one of the most important remote complications after kidney injury. Renal ischemia reperfusion (I/R) is a major cause of acute renal injury predisposing to several remote dysfunctions, including cardiac electrical disturbance. Since IL-1ß production dependent on NLRP3 represents a link between tissue malfunctioning and cardiac arrhythmias, here we tested the hypothesis that longer ventricular repolarization and arrhythmias after renal I/R depend on this innate immunity sensor. METHODS AND RESULTS: Nlrp3-/- and Casp1-/- mice reacted to renal I/R with no increase in plasma IL-1ß, different from WT (wild-type) I/R. A prolonged QJ interval and an increased susceptibility to ventricular arrhythmias were found after I/R compared to Sham controls in wild-type mice at 15 days post-perfusion, but not in Nlrp3-/- or CASP1-/- I/R, indicating that the absence of NLRP3 or CASP1 totally prevented longer QJ interval after renal I/R. In contrast with WT mice, we found no renal atrophy and no renal dysfunction in Nlrp3-/- and Casp1-/- mice after renal I/R. Depletion of macrophages in vivo after I/R and a day before IL-1ß peak (at 7 days post-perfusion) totally prevented prolongation of QJ interval, suggesting that macrophages might participate as sensors of tissue injury. Moreover, treatment of I/R-WT mice with IL-1r antagonist (IL-1ra) from 8 to 15 days post perfusion did not interfere with renal function, but reversed QJ prolongation, prevented the increase in susceptibility to ventricular arrhythmias and rescued a close to normal duration and amplitude of calcium transient. CONCLUSION: Taken together, these results corroborate the hypothesis that IL-1ß is produced after sensing renal injury through NRLP3-CASP1, and IL-1ß on its turn triggers longer ventricular repolarization and increase susceptibility to cardiac arrhythmias. Still, they offer a therapeutic approach to treat cardiac arrhythmias that arise after renal I/R.

Toll-Like Receptor 4 and NLRP3 Caspase 1- Interleukin-1ß-Axis are Not Involved in Colon Ascendens Stent Peritonitis-Associated Heart Disease.

Hemodynamic collapse and myocardial dysfunction are among the major causes of death in severe sepsis. The purpose of this study was to assess the role played by toll-like receptor 4 and by the NLRP3 inflammasome in the cardiac dysfunction that occurs after high-grade polymicrobial sepsis. We performed the colon ascendens stent peritonitis (CASP) surgery in Tlr4, Nlrp3, and caspase-1 mice. We also assessed for the first time the electrical heart function in the colon ascendens stent peritonitis (CASP) model. The QJ interval was increased in wild-type C57BL/6J mice after CASP when compared with sham controls, a result paralleled by an increase in the cardiac action potential (AP) duration (APD). The decreases in ejection fraction (EF), left ventricle end diastolic volume, stroke volume, and cardiac output found after CASP were similar among all groups of mice. Similar heart response was found when Nlrp3 mice were submitted to high-grade cecal ligation and puncture. Despite developing cardiac dysfunction similar to wild types after CASP, Nlrp3 mice had reduced circulating levels of interleukin (IL)-1ß, IL-6 and tumor necrosis factor-α. Our results demonstrate that the genetic ablation of Tlr4, Nlrp3, and caspase-1 does not prevent the cardiac dysfunction, despite preventing the increase in pro-inflammatory cytokines, indicating that these are not feasible targets to therapy in high-grade sepsis.