Altered ubiquitin/proteasome expression in anastomotic intimal hyperplasia

Area of Science:

• Biomedical Engineering
• Molecular Biology
• Vascular Surgery

Background:

• Anastomotic intimal hyperplasia is a primary cause of prosthetic arterial graft failure.
• Previous studies indicated altered proteasome gene expression using messenger RNA differential display.
• Limitations in tissue availability for early time points necessitated a more sensitive technique.

Purpose of the Study:

• To screen for altered proteasome gene expression at 48 hours and 14 days post-prosthetic arterial grafting.
• To utilize microarray gene chip technology for sensitive early gene expression analysis.

Main Methods:

• Expanded polytetrafluoroethylene grafts were implanted in canine carotid arteries (n=9).
• Perianastomotic tissue RNA was extracted at 48 hours and 14 days.
• Messenger RNA was hybridized to microarrays to identify differential gene expression compared to control carotid arteries.

Main Results:

• At 48 hours, two 26S proteasome genes and five ubiquitin pathway genes were significantly underexpressed.
• At 14 days, six ubiquitin genes and 17 26S proteasome genes were found to be significantly downregulated.
• Specific downregulated genes included 26S proteasomal subunits and various ubiquitin-related enzymes.

Conclusions:

• A decrease in ubiquitin/proteasome pathway gene expression was observed early (48 hours) and persisted at 14 days after graft implantation.
• This early and sustained underexpression may disrupt cell cycle control and matrix signaling.
• Such disruptions could contribute to the smooth muscle cell and extracellular matrix proliferation seen in anastomotic intimal hyperplasia.