Formation of cell junctions between grafted and host cardiomyocytes at the border zone of rat myocardial infarction.

Background—Cardiomyocyte transplantation is an innovative strategy for the treatment of heart failure after myocardial infarction. Cell junctions show diverse temporal polarization toward intercalated disks during postnatal development and exhibit altered distribution in diseased hearts. To elucidate the formation of cell junctions between grafted and host cardiomyocytes at the border zone of myocardial infarction, the 3D distribution of cell junctions was examined using immunohistochemistry and confocal microscopy. Methods and Results—Neonatal cardiomyocytes obtained from 3-day-old rats by collagenase digestion and Percoll density centrifugation were injected into the border zones of infarction sites 10 days after coronary ligation in adult rats. At 4 to 14 days after transplantation, hearts were harvested and processed by immunohistochemistry. Antibodies against connexin43, desmoplakin, and cadherin were used to analyze the distribution of gap junctions, desmosomes, and adherens junctions, respectively....