Expression and Cellular Localization of 15-Hydroxy-Prostaglandin-Dehydrogenase in Abdominal Aortic Aneurysm

PGE₂ has been implicated in abdominal aortic aneurysm (AAA) associated hypervascularization. PGE₂-metabolism involves 15-hydroxyprostaglandin-dehydrogenase (15-PGDH) the expression of which in AAA is unknown. The aim of this study was to examine the expression and cell distribution of 15-PGDH in AAA. Here, we show that 15-PGDH mRNA levels were significantly higher in aorta samples from patients undergoing AAA repair than in those from healthy multiorgan donors. Consequently, the ratio of metabolized PGE₂ secreted by aortic samples was significantly higher in AAA. AAA production of total PGE₂ and PGE₂ metabolites correlated positively with PGI₂ production, while the percentage of metabolized PGE₂ correlated negatively with the total amount of PGE₂ and with PGI₂. Transcript levels of 15-PGDH were statistically associated with leukocyte markers but did not correlate with microvascular endothelial cell markers. Immunohistochemistry revealed 15-PGDH in the areas of leukocyte infiltration in AAA samples, mainly associated with CD45-positive cells, but not in normal aorta samples. We provide new data concerning 15-PGDH expression in human AAA, showing that 15-PGDH is upregulated in AAA and mainly expressed in infiltrating leukocytes. Our data suggest that microvasculature was not involved in PGE₂ catabolism, reinforcing the potential role of microvasculature derived PGE₂ in AAA-associated hypervascularization.