gms | German Medical Science

Background: Cellular replacement strategies are increasingly suggested for the treatment of heart disease. However, numerous questions regarding the electrical integration of transplanted cells into cardiac tissue are still unanswered.

Aim: To develop an in vitro model to investigate the electrical integration of cells suggested for cardiac replacement strategies.

Materials and Methods: Viable tissue slices (300 µm) were prepared from late-stage (ED 16.5-17.5) murine embryonic hearts by slicing the ventricles with a vibratome. These slices were plated on planar micro-electrode arrays (MEAs; Multichannel Systems, Reutlingen, Germany) and cultured in close contact with excised spontaneously beating clusters of human embryonic stem cell-derived cardiomyocytes (hESCs). Beating of the viable slices and of the hESCs was videotaped and analyzed to judge the beating behavior. Field potential recordings of the coculture were acquired with the MEA system and analyzed offline.

Results: During the first day of coculture, ventricular tissue slices and beating areas containing hESCs exhibited a beating pattern indicating functional independence. However, after two to three days of coculturing we observed beating patterns indicating coupling (1:4, 1:3, 1:2 block, 1:1 coupling) between hESCs and the murine ventricular slices.

Conclusion: The described model allows to investigate functional integration of stem-cell derived cardiomyocytes into ventricular tissue.