AUTHOR=Fischer Dania , Sha’sha’a Mishkaat , Schenz Judith , Tayan Aycan , Mertens Christina , Decker Sebastian O. , Gallenstein Nadia , Dietrich Maximilian , Lajqi Trim , Hafner Anna , Weigand Markus A. , Ullrich Nina D. 

TITLE=An approach to evaluate the effect of inflammatory microvesicles on Ca2+ handling in human-induced pluripotent stem cell-derived cardiomyocytes

JOURNAL=Experimental Biology and Medicine

VOLUME=Volume 250 - 2025

YEAR=2025

URL=https://www.ebm-journal.org/journals/experimental-biology-and-medicine/articles/10.3389/ebm.2025.10461

DOI=10.3389/ebm.2025.10461

ISSN=1535-3699

ABSTRACT=Microvesicles (MV) isolated from septic individuals were observed to impact systemic hemodynamics and cardiac function. The aim of this in vitro study was to analyze the effects of TNFα-induced endothelial MV (TMV) and MV from septic patients (SMV) on beating frequency and Ca2+ transient kinetics of human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM). MV were isolated from supernatants of TNFα-stimulated primary human pulmonary microvascular endothelial cells (HPMEC) and plasma from 20 sepsis patients by ultracentrifugation and quantified using flow cytometry. Spontaneous Ca2+ transients were measured in hiPSC-CM using the Ca2+-sensitive ratiometric indicator fura-2 at different time points of incubation with different MV concentrations. At 16 h of incubation, higher MV concentrations showed significant differences, especially regarding decay and beating frequency. Despite high variability, at 10 × 106 MV/mL and 16 h of incubation, TMV significantly decreased frequency compared to control MV (CMV). SMV from septic patients did not reveal any significant effects on Ca2+ transients under these experimental settings. MV isolated from control or TNFα-treated HPMEC affected Ca2+ handling and spontaneous activity of hiPSC-CM, however, the measured effects were not consistent throughout the different conditions. Further refinement of the experiment conditions is needed to specify the exact conditions for crosstalk between endothelium-derived MV and cardiomyocytes.