Tetralogy of Fallot: aorto-pulmonary collaterals and pulmonary arteries have distinctly different transcriptomes.

Background: Tetralogy of Fallot patients with pulmonary atresia (TOF/PA) present a pulmonary blood supply directly from aortic collateral arteries. Major aorto-pulmonary collateral arteries (MAPCAs) present substantial clinical and surgical management challenges. Surgical operations to reestablish and promote further development of a pulmonary arterial connection preferentially utilize MAPCAs for reconstruction of central pulmonary arteries. However, the propensity of some MAPCAs to develop stenosis rather than growth may impair the response to reconstructions.

Methods: Probe sets prepared from MAPCAs, PA, and aorta mRNA were used to interrogate human genome microarrays. We compared expression differences between pairs of the three vessels to determine whether MAPCAs display distinct expression patterns.

Results: Functional clustering analysis identified differences in gene expression, which were further analyzed by gene ontology classification. A subset of highly regulated genes was validated using quantitative PCR. Expression differences among vessel types were observed for multiple gene classes. Of note, we observed that MAPCAs differentially express several genes at much higher levels than either PA or aorta.

Conclusion: MAPCAs differ from PA or aorta by significantly altered levels in gene expression, suggesting a transcriptional basis for their physiology that will guide a further understanding of the pathobiology of MAPCAs and TOF.