Descending thoracic aorta perivascular adipocytes adipogenesis is defined by their anatomical location
Hypertension, atherosclerosis, and aneurysms alter thoracic aorta structure. Aortic lesions found in these diseases show a unique anatomical distribution. For instance, calcifications and atherosclerotic lesions tend to occur more frequently in the posterior wall of the aorta compared to other regions. The role that the outer layer of the aorta, its perivascular adipose tissue (PVAT), plays in the pathogenesis of these lesions is unknown. The descending thoracic aorta's PVAT is distributed in three strips of tissue: one strip is located anterior to the aorta (AP), while the other two are positioned laterally to the vessel and are adjacent to the thoracic vertebrae (LP). Genetic tracing indicates LP's adipocytes descend from sm22a+ and Myf5+ progenitors while the anterior are from sm22a+ only. The implications of this ontology and aortic PVAT distribution on the development of adipocytes are unknown. We hypothesize that the anatomical location of adipocyte progenitors influences their adipogenic potential. PVAT from LP and AP was collected from male SD rats at 10 wks of age (n=7) to harvest progenitors by outgrowth expansion. Progenitors were differentiated for 4 d in adipogenic media. Adipogenesis was evaluated by lipid droplet and triglyceride quantification using the IncuCyte Live-Cell® system. RNA from progenitors and adipocytes was sequenced in Illumina NextSeqData, and Differential Expressed Genes (DEG) identified. Enrichment and network analyses were performed in Ingenuity Pathways (IPA). Our findings provide evidence supporting differences in adipogenic activity and extracellular matrix secretion between the LP and AP PVAT of the aorta. These differences may explain the anatomical location of aortic lesions associated with hypertension, atherosclerosis, and aneurysms. Overall design: To investigate the adipogenic potential of adipocyte progenitors in the descending thoracic aorta perivascular adipose tissue