Upregulation of Circulating Components of the Alternative Renin-Angiotensin System in Inflammatory Bowel Disease: A Pilot Study

J Renin Angiotensin Aldosterone Syst. 2015 Sep;16(3):559-69. doi: 10.1177/1470320314521086. Epub 2014 Feb 6.

Abstract

Introduction: The relationship between intestinal inflammation and circulating components of the renin-angiotensin system (RAS) is poorly understood.

Materials and 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.

Keywords: Crohn’s disease; Renin-angiotensin system; angiotensin (1–7); angiotensin II; angiotensin-converting enzyme; angiotensin-converting enzyme 2; inflammatory bowel disease; ulcerative colitis.

MeSH terms

  • Adult
  • Aged
  • Angiotensin I / blood
  • Biomarkers / blood
  • Case-Control Studies
  • Female
  • Humans
  • Inflammatory Bowel Diseases / blood*
  • Male
  • Middle Aged
  • Peptide Fragments / blood
  • Peptidyl-Dipeptidase A / blood
  • Pilot Projects
  • Renin-Angiotensin System*
  • Up-Regulation*
  • Young Adult

Substances

  • Biomarkers
  • Peptide Fragments
  • Angiotensin I
  • Peptidyl-Dipeptidase A
  • angiotensin converting enzyme 2
  • angiotensin I (1-7)