Structural remodelling of cardiomyocytes in the border zone of infarcted XXXX heart.

@entity1 @entity63 @entity1184 @entity990 @entity95 @entity1188 @entity1562 @entity583
Cardiomyocyte dedifferentiation, as detected in hibernating @entity1562 of chronic @entity63 @entity1 , is one of the characteristics seen at the border of @entity583 in small and large animals. Our objectives were to study in detail the morphological changes occurring at the border zone of a @entity95 @entity583 and its use as model for hibernating @entity1562 . Ligation of the left coronary artery (LAD) was performed on @entity95 hearts and animals were sacrificed at 2, 4, 8 and 12 weeks post- @entity1188 . These hearts together with a non-infarcted control heart were perfusion-fixed and tissue samples were embedded in @entity990 resin. Hibernating cardiomyocytes were mainly distributed in the non-infarcted region adjacent to the border zone of infarcted @entity1562 but only in a limited number. In the border zone itself vacuolated cardiomyocytes surrounded by fibrotic tissue were frequently observed. Ultrastructural analysis of these vacuolated cells revealed the presence of a basal lamina inside the vacuoles adjacent to the surrounding membrane, the presence of pinocytotic vesicles and an association with cisternae of the sarcoplasmatic reticulum. Myocyte quantitative analyses revealed a gradual increase in vacuolar area/total cell area ratio and in collagen fibril deposition inside the vacuoles from 2 to 12 weeks post- @entity1188 . Related to the remote zone, the increase in cell width of myocytes located in and adjacent to the border zone demonstrated cellular @entity1184 . These results indicate the occurrence of cardiomyocyte remodelling mechanisms in the border zone and adjacent regions of infarcted @entity1562 . It is suggested that the vacuoles represent plasma membrane invaginations and/or dilatations of T-tubular structures.
