Elevated plasma C-type natriuretic peptide concentrations in patients with chronic renal failure

C-type natriuretic peptide is a neuropeptide, which is also produced by the vascular endothelial cells. Plasma immunoreactive C-type natriuretic peptide concentrations in patients with various diseases have not yet been studied. Plasma immunoreactive C-type natriuretic peptide concentrations were studied by radioimmunoassay in normal subjects, patients with congestive heart failure, non-dialysed patients with chronic renal failure and haemodialysis patients with chronic renal failure. The C-type natriuretic peptide levels were compared with the levels of atrial natriuretic peptide and brain natriuretic peptide. Plasma immunoreactive C-type natriuretic peptide concentrations were greatly elevated in patients with chronic renal failure [non-dialysed, 13.0±4.2 pmol/l (mean±SEM), n=9, P<0.01 compared with normal subjects (4.4±0.4 pmol/l, n = 26); haemodialysis, 16.1±2.1 pmol/l, n = 13, P< 0.011, but not in patients with congestive heart failure (New York Heart Association Class II-IV, 3.0±0.7 pmol/l, n =11, P> 0.05). Plasma immunoreactive atrial natriuretic peptide and brain natriuretic peptide concentrations were elevated both in patients with congestive heart failure and in haemodialysis patients with chronic renal failure. Reverse-phase high performance liquid chromatography showed that immunoreactive C-type natriuretic peptide in plasma from normal subjects and haemodialysis patients was eluted in the positions of C-type natriuretic peptide-22 and -53. These findings suggest that C-type natriuretic peptide is a non-cardiac circulating hormone and participates in the cardiovascular regulation in a different manner from atrial natriuretic peptide and brain natriuretic peptide.