Intimal thickening after arterial balloon injury is increased by intermittent repetitive hypoxia, but intermittent repetitive hyperoxia is not protective

Lau, Antony K.; Chaufour, Xavier; McLachlan, Craig; Leichtweis, Steven B.; Celermajer, David S.; Sullivan, Colin; Stocker, Roland

doi:10.1016/j.atherosclerosis.2005.06.040

« Previous Next »Atherosclerosis
Volume 185, Issue 2 , Pages 254-263, April 2006

Intimal thickening after arterial balloon injury is increased by intermittent repetitive hypoxia, but intermittent repetitive hyperoxia is not protective

Antony K. Lau
- The Heart Research Institute, University of Sydney, Sydney, Australia
Xavier Chaufour
- Department of Vascular Surgery, University of Sydney, Sydney, Australia
Craig McLachlan
- Department of Vascular Surgery, University of Sydney, Sydney, Australia
Steven B. Leichtweis
- The Heart Research Institute, University of Sydney, Sydney, Australia
David S. Celermajer
- The Heart Research Institute, University of Sydney, Sydney, Australia
- Department of Medicine, University of Sydney, Sydney, Australia
Colin Sullivan
- Department of Vascular Surgery, University of Sydney, Sydney, Australia
Roland Stocker
- The Heart Research Institute, University of Sydney, Sydney, Australia
- Centre for Vascular Research, School of Medical Sciences, Faculty of Medicine, University of New South Wales, UNSW Sydney NSW 2052, Australia
- Department of Hematology, Prince of Wales Hospital, Sydney NSW 2052, Australia
- Corresponding author. Tel.: +61 2 9385 1309; fax: +61 2 9385 1389.

Received 22 January 2005; received in revised form 26 May 2005; accepted 21 June 2005. published online 01 August 2005.

Abstract

Hypoxia increases and hyperoxia decreases experimental atherosclerosis, but it is unclear if repetitive hypoxic and hyperoxic insults affect intimal thickening after arterial injury. Rabbits on 2% cholesterol diet for 6 weeks underwent balloon injury to the abdominal aorta (AA) after week 3, and were then exposed to normoxia (n=6), or 12h daily of intermittent repetitive hypoxia (n=6) or hyperoxia (n=6). After week 6, damaged AA and undamaged thoracic aorta (TA) were assessed for intimal thickening and lipid content. Compared with normoxia, hypoxia and hyperoxia did not alter the rise in serum cholesterol related to cholesterol feeding. However, compared to normoxia, hypoxia markedly increased the intima-to-media ratio in AA (1.18±0.09 versus 1.96±0.14, P<0.01) and TA (0.15±0.02 versus 0.41±0.01, P<0.01) whereas hyperoxia had no effect on AA disease and increased intimal thickening in TA (0.26±0.03, P<0.01). Hyperoxia promoted positive arterial remodeling in both TA and AA, resulting in larger luminal size. The cholesterol content in AA was increased by hypoxia and decreased by hyperoxia, but decreased by both treatments in TA. Lipophilic antioxidants and the proportion of arterial lipids that was oxidized were not altered by hypoxia or hyperoxia. These results suggest that intermittent repetitive hyperoxia is not protective and intermittent repetitive hypoxia promotes arterial disease in normal and injured arteries independent of lipid peroxidation.