Molecular Pathways and Animal Models of Atrioventricular Septal Defect.

Area of Science:

• Cardiovascular Development
• Congenital Heart Disease Research
• Molecular Embryology

Background:

• Proper formation of the four-chambered heart relies on accurate septation of atrial and ventricular chambers.
• Defects in septation lead to mixing of oxygenated and deoxygenated blood, causing congenital heart malformations.
• Atrioventricular septal defects (AVSD) are characterized by atrial septal defects, common atrioventricular valves, and often ventricular septal defects.

Purpose of the Study:

• To review current knowledge on the molecular mechanisms underlying AVSD pathogenesis.
• To discuss the role of various components of the atrioventricular mesenchymal complex in AVSD.
• To summarize findings from animal models relevant to AVSD development.

Main Methods:

• Review of existing literature on AVSD molecular mechanisms.
• Analysis of data from animal models of AVSD.
• Examination of the roles of endocardial cushions, dorsal mesenchymal protrusion (DMP), and primary atrial septum mesenchymal cap.

Main Results:

• Historically, AVSD was attributed to faulty endocardial cushion development.
• Recent studies indicate that impaired development of other atrioventricular mesenchymal components also cause AVSD.
• The DMP's role in AVSD pathogenesis is well-established in animal models; the primary atrial septum's mesenchymal cap may also be involved.

Conclusions:

• AVSD pathogenesis is complex, involving multiple components of the atrioventricular region.
• Animal models are crucial for understanding the molecular basis of AVSD.
• Further research into the mesenchymal cap and DMP is warranted for a comprehensive understanding of AVSD.