Related Experiment Videos
Hypoplastic left heart syndrome myocytes are differentiated but possess a unique phenotype
Teresa J Bohlmeyer1, Steve Helmke, Shuping Ge
1Department of Medicine, Division of Cardiology, University of Colorado Health Sciences Center, Denver, CO 80246, USA.
Insights
Hypoplastic left heart syndrome (HLHS) myocytes are differentiated but show unique gene expression, including inappropriate PECAM-1 (CD31) levels. This study reveals a distinct molecular profile in HLHS heart muscle cells.
Area of Science:
- Cardiology
- Molecular Biology
- Developmental Biology
Background:
- Hypoplastic left heart syndrome (HLHS) is a severe congenital heart defect causing underdevelopment of the left heart side.
- HLHS accounts for a significant portion of infant cardiac mortality.
- Limited data exists on gene expression within HLHS myocytes.
Purpose of the Study:
- To investigate the gene expression profile of myocytes in hypoplastic left heart syndrome (HLHS).
- To characterize the molecular phenotype of HLHS cardiomyocytes.
Main Methods:
- Analysis of HLHS heart tissue using histology, immunohistochemistry, quantitative PCR, and 2-D gel electrophoresis with mass spectrometry.
- Examination of myocyte differentiation markers and gene/protein expression patterns.
Main Results:
- HLHS myocytes exhibit differentiation but disorganized bundles and abnormal vasculature.
- Quantitative PCR revealed a fetal or 'heart failure' gene expression pattern.
- Inappropriate expression of platelet-endothelial cell adhesion molecule-1 (PECAM-1, CD31) was observed in all HLHS myocyte samples.
Conclusions:
- HLHS myocytes, despite differentiation, possess a unique and abnormal gene expression profile.
- The aberrant expression of PECAM-1 (CD31) suggests a role in HLHS pathophysiology.
- Findings provide novel insights into the molecular basis of HLHS.
Introduction:
Hypoplastic left heart syndrome (HLHS) is the term used to describe a group of congenital malformations characterized by marked underdevelopment of the left side of the heart. HLHS accounts for nearly 25% of cardiac deaths in the first year of life. Although much has been reported regarding diagnosis, gross morphology and surgical treatment, no information on gene expression in HLHS myocytes is available.
Methods:
We examined heart tissue from patients with HLHS using routine histology, immunohistochemistry, quantitative polymerase chain reaction (PCR), two-dimensional (2-D) gel electrophoresis and protein identification by mass spectrometry.
Results:
Histologic examination of right and left ventricles from HLHS patients revealed characteristic features of myocyte differentiation, including striations and intercalated disc formation. Immunohistochemical staining using antibody to N-cadherin demonstrated clear development of intercalated discs between myocytes. However, many of the myocytes contained scant cytoplasm and were grouped in small, disorganized bundles separated by abundant connective tissue and dilated, thin-walled vessels. Quantitative PCR analysis demonstrated that both left and right ventricular tissue from HLHS hearts expressed the fetal or "heart failure" gene expression pattern. Two-dimensional gel electrophoresis and protein identification by mass spectrometry also confirmed that myocytes from HLHS ventricles were differentiated but expressed the fetal isoform of some cardiac specific proteins. However, HLHS myocytes in all of the heart samples (n=21) were inappropriately expressing platelet-endothelial cell adhesion molecule-1 (PECAM-1, CD31), a member of the cell adhesion molecule (CAM) family that has a primary role in the regulation of tissue morphogenesis. These findings indicate that myocytes from HLHS syndrome patients, while differentiated, have a unique gene expression pattern.