Abstract 18949: The Role of CDKN2B in Vascular Disease
Background: Genome wide association studies (GWA) have identified genetic variation associated with an increased risk for coronary heart disease (CHD). A region in an intergenic segment of chromosome 9p21.3 was determined to be the most highly associated with disease. More recent human genetics studies have implicated the nearby CDKN2B gene in this region as causal. Basic molecular biology and animal model studies are necessary to identify and characterize the mechanisms by which this gene alters risk for CHD.
Methods: To evaluate the in vivo role of CDKN2B in an animal model of vascular remodeling, we evaluated CDKN2B knockout mice and control C57BL/6 control mice in the carotid ligation model. Harvested carotids were sectioned and vascular cross-sectional areas were calculated with H&E stained sections. We also performed in situ experiments with TUNEL, BRDU, SMA, and DAPI staining to investigate differences in apoptosis, cell proliferation, smooth muscle cell proliferation, and total cell count, respectively.
Results: Compared to wildtype C57BL/6 animals, CDKN2B deficient mice on a C57BL/6 background had significantly less neointima (0.051 μm2 ± 0.011 μm2 vs 0.026 μm2 ± 0.004 μm2, P<0.05) and a lower intima/media ratio (1.579 ± 0.297 vs 0.791 ± 0.143, P<0.05) in the carotid artery 400 μm distal to the ligation site. Further from the lesion, CDKN2B knockout mice displayed not only less neointima (0.035 μm2 ± 0.011 μm2 vs 0.011 μm2 ± 0.003 μm2, P<0.05) but also less media (0.031 μm2 ± 0.002 μm2 vs 0.023 μm2 ± 0.002 μm2, P<0.05) relative to controls 800 μm distal to the ligation site. Similarly, they also had less media 1200 μm distal to the ligation site (0.029 μm2 ± 0.001 μm2 vs 0.025 μm2 ± 0.001 μm2, P<0.05). CDKN2B knockouts had significantly fewer intimal cells (347.6 ± 83.71 vs 171.0 ± 42.19, P<0.05) and a trend towards fewer medial smooth muscle cells, fewer proliferating cells, and more apoptotic cells in the intima and media.
Conclusions: While additional studies are required, initial experiments in the carotid ligation model suggest that CDKN2B expression is harmful in the context of vascular remodeling.
- © 2010 by American Heart Association, Inc.