Basic/Translational Science -> Genomics: Translational D-PO01 - Featured Poster Session (ID 11) Poster

D-PO01-206 - Preclinical Validation Of Novel Optical Imaging Agents For The Real-time Visualization Of The Cardiac Conduction System (ID 964)

Abstract

Background: Coordinated beating of the heart relies on the cardiac conduction system (CCS). Accidental intraoperative damage to the CCS represents a significant complication in pediatric and adult cardiac surgeries. To date, there exists no intraoperative method to visualize the CCS.
Objective: Generate novel optical imaging agents for real-time CCS visualization.
Methods: Differential gene expression was determined using the non-parametric Wilcoxon rank sum test and significance using the Bonferroni correction. All murine validation experiments employed at least 4 biological replicates per condition and statistical analyses were performed using the unpaired Student’s t test.
Results: Gene expression analyses of our scRNAseq dataset of the developing murine CCS (Goodyer et al Circ Res 2019) revealed significant enrichment of a host of novel, CCS-specific cell surface genes. A subset of these genes, including the cell adhesion molecule Neuroplastin (Nptn), was subsequently validated in the CCS of mice and/or humans. Next, two different optical imaging agents were created consisting of a near-infrared (NIR) dye conjugated to antibodies directed against CCS-specific cell surface markers, both known (Contactin2) and novel (Nptn). Each optical imaging agent demonstrated high sensitivity and specificity in labeling the entire CCS in vivo following a single intravenous injection in mice. Specificity was confirmed within intact, whole hearts using both closed-field NIR imaging and whole mount immunolabeling with volume imaging (iDISCO+). Dosage, time course and biodistribution analyses were performed for delivery optimization. Finally, surface ECGs showed no significant perturbations in all measured intervals following injection.
Conclusion: Our study has uncovered a host of new CCS-specific cell surface markers. Further, we created novel optical imaging agents that showed safe and highly specific labeling of the entire CCS when delivered as single systemic applications in mice. These tools provide a proof-of-principle for the in vivo labeling of cardiac substructures for the first time and lay the foundation for translational opportunities in the real-time visualization of the CCS during cardiothoracic surgeries and other cardiac interventions.

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