Cardiopulmonary bypass reduces atrial Na+-K+-ATPase expression in children

Area of Science:

• Pediatric Cardiology
• Molecular Cardiology
• Cardiovascular Surgery

Background:

• Cardiopulmonary bypass (CPB) can cause myocardial dysfunction.
• The sodium-potassium adenosine triphosphatase (Na(+)-K(+)-ATPase) is crucial for heart muscle function.
• Developmental regulation of Na(+)-K(+)-ATPase necessitates pediatric-specific research.

Purpose of the Study:

• To investigate the impact of CPB on Na(+)-K(+)-ATPase expression in pediatric patients.
• To determine if underlying heart defects influence susceptibility to CPB-induced molecular changes.

Main Methods:

• Myocardial tissue samples were collected from pediatric patients undergoing heart surgery before and after CPB.
• Patients were categorized into groups with (VO) and without (NO) left-to-right shunts at the atrial level.
• Expression levels of Na(+)-K(+)-ATPase isoforms were analyzed using molecular techniques.

Main Results:

• CPB significantly decreased the expression of Na(+)-K(+)-ATPase isoforms ATP1A1 and ATP1A3.
• This reduction in Na(+)-K(+)-ATPase expression was exclusively observed in the group with left-to-right atrial shunts (VO).
• No patients exhibited clinical heart failure before or after surgery, suggesting an early molecular event.

Conclusions:

• Underlying left-to-right atrial shunts increase susceptibility to CPB-induced alterations in Na(+)-K(+)-ATPase expression.
• Reduced Na(+)-K(+)-ATPase mRNA expression appears to be an early molecular consequence of CPB in vulnerable pediatric patients.
• These findings underscore the importance of considering congenital heart defects when assessing CPB risks in children.