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Antisense oligonucleotides to c-fos and c-jun inhibit intimal thickening in a rat vein graft model
W D Suggs1, S C Olson, D Madnani
1Division of Vascular Surgery, Montefiore Medical Center, New York, NY 10467, USA.
Background:
C-fos and c-jun are 2 immediate early genes that have been implicated in the stimulation of vascular smooth muscle cell proliferation and migration. In previous experiments in our laboratory with a rat vein graft model a 2- to 3-fold increase of messenger RNA of c-fos and c-jun were noted 1 hour after vein graft perfusion. Because c-fos and c-jun are up-regulated after the perfusion of vein grafts, the purpose of this study was to delineate the temporal expression of c-fos and c-jun protein and to study the effect of antisense oligonucleotides (ASO) to c-fos and c-jun on intimal thickening observed in this model.
Methods:
Sprague-Dawley rats underwent bilateral interposition femoral artery grafts with use of the superficial epigastric vein, which was harvested from 15 minutes up to 2 weeks and analyzed by Western blot for Fos and Jun protein. Additional rats underwent bypasses and at the time of the procedure 1 graft was treated with a pluronic gel containing an ASO to c-fos, c-jun, or sense and the contralateral side was treated with pluronic gel only. The vein grafts were harvested 2 weeks after the procedure and perfusion fixed. After longitudinal sectioning, the intimal and total wall thicknesses were measured in the perianastamotic and midgraft regions by a morphometric digitizing microscope and the statistics were analyzed by a paired Student's t test.
Results:
Protein analysis by Western blot showed that c-fos levels rose quickly within 2 hours and leveled at 6 hours 40-fold above basal levels after vein graft perfusion. Similarly, c-jun levels rose 10-fold above basal levels after 15 minutes and peaked at 2 hours 120-fold above basal levels. The treatment of the vein grafts with these ASOs resulted in a reduction of about 30% in the thickness of the intimal layer and the total wall thickness in both the perianastomotic and the midgraft regions, which was statistically significant different from control veins.
Conclusion:
These results indicate a possible therapeutic role for ASO to immediate early genes in the treatment of vein graft intimal hyperplasia.
Insights
Antisense oligonucleotides (ASO) targeting c-fos and c-jun genes significantly reduced vein graft intimal hyperplasia by 30%. This study highlights a potential therapeutic strategy for preventing intimal thickening in vein grafts.
Area of Science:
- Vascular Biology
- Gene Expression
- Surgical Research
Background:
- C-fos and c-jun are immediate early genes involved in vascular smooth muscle cell proliferation and migration.
- Previous studies showed increased c-fos and c-jun mRNA levels in a rat vein graft model post-perfusion.
- Understanding the temporal protein expression of these genes is crucial for therapeutic interventions.
Purpose of the Study:
- To determine the temporal expression patterns of c-fos and c-jun proteins after vein graft perfusion.
- To evaluate the efficacy of antisense oligonucleotides (ASO) targeting c-fos and c-jun in mitigating intimal thickening in vein grafts.
Main Methods:
- Western blot analysis was used to quantify Fos and Jun protein levels in rat vein grafts over time.
- Antisense oligonucleotides (ASO) against c-fos and c-jun, or a sense control, were administered via pluronic gel to grafted veins.
- Intimal and total wall thicknesses were measured morphometrically in perianastomotic and midgraft regions 2 weeks post-procedure.
Main Results:
- C-fos protein levels increased 40-fold within 6 hours post-perfusion, while c-jun levels peaked 120-fold higher at 2 hours.
- ASO treatment targeting c-fos and c-jun led to a statistically significant 30% reduction in intimal and total wall thickness.
- Reductions in thickness were observed in both perianastomotic and midgraft regions compared to control veins.
Conclusions:
- The study demonstrates that c-fos and c-jun proteins are rapidly upregulated following vein graft perfusion.
- Antisense oligonucleotides targeting these immediate early genes show therapeutic potential in reducing vein graft intimal hyperplasia.
- Targeting c-fos and c-jun represents a promising strategy for managing post-vein graft complications.