PROTEOGLYCAN GENE-EXPRESSION IS DECREASED IN ABDOMINAL AORTIC-ANEURYSMS

Background. Abdominal aortic aneurysms (AAA) are characterized by both increases in proteolysis and changes in the biosynthesis of the extra cellular matrix (ECM) proteins. Proteoglycans are important components of the ECM, particularly the small proteoglycans, biglycan and decori n, Biglycan and decorin regulate cell proliferation and collagen assem bly. Therefore, the purpose of this study is to quantify the levels of mRNA for biglycan and decorin in normal aorta (NA) and AAA. Materials and methods. Northern blot hybridization and competitive polymerase c hain reaction using gene-specific external standards were used to quan tify mRNA levels of bigylcan and decorin in RNA derived from AAA and N A. Results are expressed as a percentage of glyceraldehyde-3-phosphate dehydrogenase or normalized to ribosomal RNA content and compared usi ng the unpaired t test. Results. A statistically significant 15-fold d ecrease in biglycan mRNA expression was observed in AAA compared to NA (176.9% vs 11.8%, P < 0.001). In contrast to biglycan, the decorin mR NA expression is unchanged in AAA compared to NA. Conclusions. The mar ked decrease in biglycan mRNA levels is unique to aneurysmal disease o f the aorta. In atherosclerosis and restenosis, biglycan expression is increased in comparison with normal artery. This decrease in biglycan expression may reflect important regulatory changes specific for the AAA. Furthermore, a decrease in biglycan gene expression and biosynthe sis could have a broad impact on the physiology and matrix architectur e of the aorta. (C) 1998 Academic Press.