Adrenomedullin and nitrite levels in children with minimal change nephrotic syndrome.

Nitric oxide (NO) serves many functions within the kidney, and recent evidence suggests that NO contributes to glomerular injury. Adrenomedullin (AM) is a novel hypotensive peptide originally isolated from human pheochromocytoma. Recent studies showed that plasma AM concentrations correlated with the extent of proteinuria. We have examined the possible role of these two agents by studying plasma and urinary total nitrite (NO-2 + NO-3) and AM levels in children with minimal change nephrotic syndrome (MCNS). In comparison with healthy controls, children with MCNS had increased urinary nitrite excretion (micromol/mg urinary creatinine), irrespective of whether the disease was in relapse or remission (3.2+/-0.2 in relapse, n=13; 1.9+/-0.3 in remission, n=12; 1.0+/-0.2 in controls, n=10, P<0.05). Plasma nitrite levels (micromol/l) were high in relapse compared with controls (53.2+/-8.7 vs. 32+/-4.0, P<0.05). Plasma AM levels (pmol/ml) were decreased in relapse (27.6+/-1.4 in relapse, 43.3+/-1.2 in remission, 41.5+/-1.6 in controls, P<0.05). Urinary AM levels (pmol/mg urinary creatinine) were significantly higher in relapse than in remission and in controls (156+/-43 in relapse, 56+/-18 in remission, 36+/-16 in controls, P<0.05). Our data indicate that NO may play a role in mediating the clinical manifestations of MCNS in children. However, changes in AM levels may be the result of heavy proteinuria.