Arterial vs venous expression of genes: differences in inflammatory genes

Arteries and veins modulate cardiovascular homeostasis and contribute to the pathogenesis of hypertension. Functional differences between normal arteries and veins are based upon differences in gene expression. To better characterize these expression patterns, and to identify candidate genes that could be manipulated selectively in the venous system, we performed whole genome expression profiling of rat arteries and veins using the CodeLink platform. We used the major artery and vein of the rat, the thoracic aorta and caudal vena cava, respectively. Expression of mRNA for thrombospondins (TSP-1, 2, 4) was greater than 5-fold higher in veins vs arteries. The most prominent gene expression difference between the normal aorta and vena cava was pancreatitis associated protein (PAP1), a protein with anti-inflammatory functions that was 64-fold higher in vena cava vs aorta. Higher mRNA expression of TSP-1, TSP-2, TSP-4 and PAP1 in vena cava vs aorta was confirmed with real time RT-PCR. Importantly, immunohistochemical analysis of blood vessels sections qualitatively confirmed a higher expression of proteins in vena cava vs aorta. These studies report a difference in inflammatory genes in arteries vs veins. A particularly notable finding is the discovery of PAP1 mRNA and protein expression in peripheral blood vessels with a substantially higher expression in the veins. Data from these studies may provide novel insights into the genetic basis for functional differences between arteries and veins in health and disease. Whole genome expression profiling of aorta and vena cava whole tissues from normal male Sprague-Dawley rats (6 biological replicates each) was performed using the CodeLink Rat Whole Genome Bioarrays.