title: Novel findings: Expression of angiotensin-converting enzyme and angiotensin-converting enzyme 2 in thoracic aortic dissection and aneurysm.
abstract: BACKGROUND
  Angiotensin-converting enzyme (ACE) and ACE2 are key regulators of the renin-angiotensin system, which has been shown to participate in a series of cardiovascular diseases. We hypothesized that dysregulated gene expression of ACE and ACE2 contribute to the formation of thoracic aortic dissection and aneurysm.
  
  
  METHODS
  We assessed ACE plasma concentration in 73 patients with acute thoracic aortic dissection (n=34), aneurysm (n=18), coronary heart disease (n=21) and 13 healthy volunteers. ACE and ACE2 gene expression in available aortic tissues was also examined by using quantitative real-time polymerase chain reaction.
  
  
  RESULTS
  In patients with acute aortic dissection, ACE plasma concentration and its mRNA level in aortic tissue were markedly reduced compared with those in patients with aneurysm, coronary heart disease and healthy controls. The level of ACE2 gene expression in dissection samples was also significantly lower than that in aneurysm (8.01±7.44, p<0.01) and coronary heart disease groups (9.61±11.54, p<0.01). A strong correlation was observed between the gene expressions of ACE and those of ACE2, and ACE to ACE2 ratio was significantly elevated in dissection tissues.
  
  
  CONCLUSIONS
  Imbalanced down-regulation of ACE and ACE2 mRNA expression levels may play an important role in the development and progression of thoracic aortic aneurysmal dilatation and subsequently dissection.
authors.affiliation: Department of Cardiovascular Surgery, West China Hospital, Sichuan University, Chengdu, Sichuan, People's Republic of China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Cardiovascular Surgery, West China Hospital, Sichuan University, Chengdu, Sichuan, People's Republic of China.
authors.forename: Jia
authors.initials: J
authors.lastname: Hu
authors.affiliation: Department of Cardiovascular Surgery, West China Hospital, Sichuan University, Chengdu, Sichuan, People's Republic of China.
authors.forename: Hong
authors.initials: H
authors.lastname: Qian
authors.affiliation: Department of Cardiovascular Surgery, West China Hospital, Sichuan University, Chengdu, Sichuan, People's Republic of China.
authors.forename: Jun
authors.initials: J
authors.lastname: Gu
authors.affiliation: Department of Cardiovascular Surgery, West China Hospital, Sichuan University, Chengdu, Sichuan, People's Republic of China.
authors.forename: Wei
authors.initials: W
authors.lastname: Meng
authors.affiliation: Department of Cardiovascular Surgery, West China Hospital, Sichuan University, Chengdu, Sichuan, People's Republic of China doc.li@163.com.
authors.forename: Er-yong
authors.initials: EY
authors.lastname: Zhang
mesh_terms: D000085962:Angiotensin-Converting Enzyme 2; D001014:Aortic Aneurysm / Q000097:blood / Q000201:enzymology* / Q000235:genetics; D017545:Aortic Aneurysm, Thoracic / Q000097:blood / Q000201:enzymology* / Q000235:genetics; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D008297:Male; D008875:Middle Aged; D007703:Peptidyl-Dipeptidase A / Q000097:blood / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D012333:RNA, Messenger; C488034:ACE protein, human; D007703:Peptidyl-Dipeptidase A; C000705307:ACE2 protein, human; D000085962:Angiotensin-Converting Enzyme 2
keywords: Angiotensin-converting enzyme; renin–angiotensin system; thoracic aortic aneurysm; thoracic aortic dissection