title: Upregulation of circulating components of the alternative renin-angiotensin system in inflammatory bowel disease: A pilot study.
abstract: BACKGROUND
  The relationship between intestinal inflammation and circulating components of the renin-angiotensin system (RAS) is poorly understood.
  
  
  METHODS
  Demographic and clinical data were obtained from healthy controls and patients with inflammatory bowel disease (IBD). Plasma concentrations of the classical RAS components (angiotensin-converting enzyme (ACE) and angiotensin II (Ang II)) and alternative RAS components (ACE2 and angiotensin (1-7) (Ang (1-7))) were analysed by radioimmuno- and enzymatic assays. Systemic inflammation was assessed using serum C-reactive protein (CRP), white cell count, platelet count and albumin, and intestinal inflammation by faecal calprotectin.
  
  
  RESULTS
  Nineteen healthy controls (11 female; mean age 38 years, range 23-68), 19 patients with Crohn's disease (11 female; aged 45 years, range 23-76) and 15 patients with ulcerative colitis (6 female; aged 42 years, 26-64) were studied. Circulating classical RAS component levels were similar across the three groups, whereas ACE2 activity and Ang (1-7) concentrations were higher in patients with IBD compared to controls (ACE2: 21.5 vs 13.3 pmol/ml/min, p<0.05; Ang (1-7): 22.8 vs 14.1 pg/ml, p<0.001). Ang (1-7) correlated weakly with platelet and white cell counts, but not calprotectin or CRP, in patients with IBD.
  
  
  CONCLUSIONS
  Circulating components of the alternative RAS are increased in patients with IBD.
authors: Department of Gastroenterology and Hepatology, Eastern Health, Australia Eastern Health Clinical School, Monash University, Australia Mayur.Garg@monash.edu.
authors: Mayur
authors: M
authors: Garg
authors: Department of Medicine, The University of Melbourne, Australia.
authors: Louise M
authors: LM
authors: Burrell
authors: Department of Medicine, The University of Melbourne, Australia.
authors: Elena
authors: E
authors: Velkoska
authors: Department of Medicine, The University of Melbourne, Australia.
authors: Karen
authors: K
authors: Griggs
authors: Department of Medicine, The University of Melbourne, Australia Gastroenterology and Liver Transplant Unit, Austin Hospital, Australia.
authors: Peter W
authors: PW
authors: Angus
authors: Eastern Health Clinical School, Monash University, Australia Department of Gastroenterology, Department of Gastroenterology, The Alfred Hospital and Monash University, Australia.
authors: Peter R
authors: PR
authors: Gibson
authors: Department of Gastroenterology and Hepatology, Eastern Health, Australia Eastern Health Clinical School, Monash University, Australia.
authors: John S
authors: JS
authors: Lubel
mesh_terms: D000328:Adult; D000368:Aged; D000803:Angiotensin I / Q000097:blood; D000085962:Angiotensin-Converting Enzyme 2; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000097:blood*; D008297:Male; D008875:Middle Aged; D010446:Peptide Fragments / Q000097:blood; D007703:Peptidyl-Dipeptidase A / Q000097:blood; D010865:Pilot Projects; D012084:Renin-Angiotensin System; D015854:Up-Regulation; D055815:Young Adult
chemical_list: D015415:Biomarkers; D010446:Peptide Fragments; D000803:Angiotensin I; D007703:Peptidyl-Dipeptidase A; C000705307:ACE2 protein, human; D000085962:Angiotensin-Converting Enzyme 2; C118790:angiotensin I (1-7)
keywords: Crohn’s disease; Renin-angiotensin system; angiotensin (1–7); angiotensin II; angiotensin-converting enzyme; angiotensin-converting enzyme 2; inflammatory bowel disease; ulcerative colitis