Mayur Garg1, Louise M Burrell2, Elena Velkoska2, Karen Griggs2, Peter W Angus3, Peter R Gibson4, John S Lubel5. 1. Department of Gastroenterology and Hepatology, Eastern Health, Australia Eastern Health Clinical School, Monash University, Australia Mayur.Garg@monash.edu. 2. Department of Medicine, The University of Melbourne, Australia. 3. Department of Medicine, The University of Melbourne, Australia Gastroenterology and Liver Transplant Unit, Austin Hospital, Australia. 4. Eastern Health Clinical School, Monash University, Australia Department of Gastroenterology, Department of Gastroenterology, The Alfred Hospital and Monash University, Australia. 5. Department of Gastroenterology and Hepatology, Eastern Health, Australia Eastern Health Clinical School, Monash University, Australia.
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.
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.