Ultrastructural changes in the myocardium due to acute uremic syndrome

The acute uremic syndrome caused by bilateral ligation of the ureters leads to ultrastructural changes in the myocardium after 12 hours. They are characterized by dilatation of the tubules of the endoplasmic reticulum and by the focal disintegration of mitochondria. After 24 hours, besides damaged mitochondria the glycogen granules were reduced and the number of pinocytic vesicles in endothelial cells increased. After 48 hours advanced changes of mitochondria associated with myelin structure and dense bodies could be observed. The myofibrils were fragmented. Sometimes contraction rings occurred. After 72 hours all myocardial structures were strongly damaged, especially in the subendocardial and subepicardial regions. In this period the hyperhydration of the myocardium led to dissociation of the myofibrillar structures.