Transcriptomic and physiological analyses reveal temporal changes contributing to the delayed healing response to arterial injury in diabetic rats

Background: Atherosclerosis is a leading cause of mortality in the rapidly growing population 3 with diabetes mellitus. Vascular interventions in diabetic patients can lead to complications attributed to defective vascular remodeling and impaired healing response in the vessel wall. In this study, we aim to elucidate the molecular differences in the vascular healing response over time using a rat model of arterial injury applied to healthy and diabetic conditions. Methods and Results: Wistar (healthy) and Goto-Kakizaki (GK, diabetic) rats (n = 40 per strain) were subjected to left common carotid artery (CCA) balloon injury and euthanized at different timepoints: 0 and 20 hours, 5 days, 2, 4 and 6 weeks. Non-invasive morphological and physiological assessment of the CCA was performed with Ultrasound biomicroscopy (Vevo 2100) and corroborated with histology. Total RNA was isolated from the injured CCA at eachtimepoint, and microarray profiling was performed (n=3 rats per timepoint, RaGene-1_0-st-v1 platform). Bioinformatic analyses were conducted using R software, DAVID bioinformatic tool, online STRING database and Cytoscape software. Significant increase in the neointimal thickness (p<0.01; 2-way ANOVA) as well as exaggerated negative remodeling was observed after 2 weeks of injury in GK compared to heathy rats, which Journal Pre-proof was confirmed by histological analyses. Bioinformatic analyses showed defective expression patterns for smooth muscle cells and immune cell markers, along with reduced expression of key extracellular matrix (ECM) related genes and increased expression of pro-thrombotic genes, indicating potential faults on cell regulation level. Transcription factor – protein-protein interaction (TF-PPI) analysis provided mechanistic evidence with an array of transcription factors dysregulated in diabetic rats.