Abstrakt
Congenital heart disease is caused by abnormalities in the first 6-8 weeks of fetal life; incidence of heart malformations is approximately eight out of 1000; they resulted from aberrant organogenesis due to dysfunction of genes and the encoded proteins. We, therefore, analyzed protein and phospholipids profiles of human myocardium (tissue samples were obtained during surgery of children with normoxemic and hypoxemic congenital heart disease).
Protein profile of the atrial and ventricular myocardium differs significantly; higher concentration of non-collagenous proteins due to contractile ones and lower concentration of extracellular matrix proteins (ECM) due to pepsin-insoluble collagenous proteins were in ventricles. Furthermore, there were significant differences in activities of metabolic enzymes from both glycolytic and oxidative pathways; it correlated with higher amount of cardiolipin in ventricle (mitochondrial phospholipids).
Moreover, electrophoretic pattern of both heavy and light chains of myosin in ventricular and atrial musculature of damage myocardium were different; however, hypoxemia decreased ATPase activity of myosin in ventricle only. Compartmentation of troponin T between myofibrillar and cytosolic pools was not affected by hypoxemia.
Synthesis of newly formed collagenous proteins depend on balance between synthetic and degradation processes; they are mediated by metaloproteinases (major band in atria and ventricle has mol. weight of 95kDa). Hypoxemia induced in atria both higher amount of collagen (predominantly collagen III) and activation of metaloproteinases.
Significantly higher concentration of phospholipids was in ventricles; hypoxemia did not affected this atrio/ventricular difference. However, composition of phospholipids species in both parts of diseased myocardium did not differ (phosphatidylcholine and phosphatidylethanolamine occupied about 70% from A phosholipids).
Surgeons, who are reconstructing cardiac anatomy, should be aware that they are dealing with biochemical abnormal tissue and they should respect atrio/ventricular differences.