title: Tissue vibration induces carotid artery endothelial dysfunction: a mechanism linking snoring and carotid atherosclerosis?
abstract: OBJECTIVE
  We have previously identified heavy snoring as an independent risk factor for carotid atherosclerosis. In order to explore the hypothesis that snoring-associated vibration of the carotid artery induces endothelial dysfunction (an established atherogenic precursor), we utilized an animal model to examine direct effects of peri-carotid tissue vibration on carotid artery endothelial function and structure.
  
  
  METHODS
  In supine anesthetized, ventilated rabbits, the right carotid artery (RCA) was directly exposed to vibrations for 6 h (peak frequency 60 Hz, energy matched to that of induced snoring in rabbits). Similarly instrumented unvibrated rabbits served as controls. Features of OSA such as hypoxemia, large intra-pleural swings and blood pressure volatility were prevented. Carotid endothelial function was then examined: (1) biochemically by measurement of tissue cyclic guanosine monophosphate (cGMP) to acetylcholine (ACh) and sodium nitroprusside (SNP); and (2) functionally by monitoring vessel relaxation with acetylcholine in a myobath.
  
  
  RESULTS
  Vessel cGMP after stimulation with ACh was reduced in vibrated RCA compared with unvibrated (control) arteries in a vibration energy dose-dependent manner. Vibrated RCA also showed decreased vasorelaxation to ACh compared with control arteries. Notably, after addition of SNP (nitric oxide donor), cGMP levels did not differ between vibrated and control arteries, thereby isolating vibration-induced dysfunction to the endothelium alone. This dysfunction occurred in the presence of a morphologically intact endothelium without increased apoptosis.
  
  
  CONCLUSIONS
  Carotid arteries subjected to 6 h of continuous peri-carotid tissue vibration displayed endothelial dysfunction, suggesting a direct plausible mechanism linking heavy snoring to the development of carotid atherosclerosis.
authors.affiliation: Ludwig Engel Centre for Respiratory Research, Westmead Millennium Institute, Westmead, NSW, Australia. jingun_cho@wmi.usyd.edu.au
authors.forename: Jin-Gun
authors.initials: JG
authors.lastname: Cho
authors.forename: Paul K
authors.initials: PK
authors.lastname: Witting
authors.forename: Manisha
authors.initials: M
authors.lastname: Verma
authors.forename: Ben J
authors.initials: BJ
authors.lastname: Wu
authors.forename: Anu
authors.initials: A
authors.lastname: Shanu
authors.forename: Kristina
authors.initials: K
authors.lastname: Kairaitis
authors.forename: Terence C
authors.initials: TC
authors.lastname: Amis
authors.forename: John R
authors.initials: JR
authors.lastname: Wheatley
mesh_terms: D000818:Animals; D002340:Carotid Artery Diseases / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology; D002470:Cell Survival; D006152:Cyclic GMP / Q000378:metabolism; D004195:Disease Models, Animal; D004730:Endothelium, Vascular / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D008297:Male; D011817:Rabbits; D012913:Snoring / Q000150:complications* / Q000473:pathology / Q000503:physiopathology; D014732:Vibration / Q000009:adverse effects*
chemical_list: D006152:Cyclic GMP