Gene expression changes: five years after creation of elastase-induced aneurysms.

Purpose: Intracranial saccular aneurysms are associated with chronic remodeling of the arterial wall. The pathobiology of aneurysm growth and rupture is poorly understood. The present study was performed to study the gene expression patterns in elastase-induced saccular aneurysms in rabbits 5 years after aneurysm creation, compared with unoperated control arteries.

Materials And Methods: Elastase-induced saccular aneurysms were created in 25 rabbits and followed up for 5 years. Thirteen rabbits died during follow-up for reasons unrelated to the aneurysms. RNA was isolated from aneurysm tissue and the control contralateral common carotid artery in five of the 12 surviving animals, and analyzed for gene expression by using human gene microarrays. Genes with statistical differences between groups (P < .05 and fold change ≥ 1.5 and ≤ 0.75) were considered differentially expressed. Real-time polymerase chain reaction (RT-PCR) was used for confirmation of gene microarray findings for selected genes.

Results: Fifty-three of 13,353 genes (0.4%) were differentially expressed in the aneurysms compared with the unoperated control arteries. Molecular and functional pathway analysis revealed that immunoregulatory molecules, growth factors, cell adhesion molecules, and structural molecules were differentially expressed in the aneurysms compared with controls. RT-PCR results of selected genes confirmed the differential expression identified by using the gene chip microarray.

Conclusions: Significant modulation in a variety of biochemical and cellular functions in chronic aneurysms provides molecular insights into the pathophysiology of saccular aneurysms.