Aim: Adrenomedullin (AM), a novel peptide recently isolated from pheochromocytoma, eliciting vasorelaxing activity, is the strongest among all known peptides. AM has been detected in the adrenal medulla, cardiac tissue, lung and kidney. Immunohistochemical studies have demonstrated the localization of AM in glomeruli, tubules and collecting cells of the kidney. Clinically, plasma and urinary AM levels are altered in patients with different renal disease. The present study aims to determine plasma and urinary AM levels in children with acute pyelonephritis (APN) and compare the results with a control group.
Materials and methods: The study group was comprised of 19 patients with APN aged 11.6 +/- 3.7 months (range, 6-18 months) and the control group consisted of 16 cases aged 11.5 +/- 3.2 months (range, 7-16 months). Acute pyelonephritis was diagnosed by clinical, laboratory and imaging methods. Plasma and urinary AM levels were measured by high performance liquid chromotography (HPLC).
Results: The plasma AM levels were lower in APN patients (33.40 +/- 2.27 pmol/mL) than in the control group (43.76 +/- 4.27 pmol/mL) (P < 0.001), whereas the urinary AM levels were higher in APN patients (248.58 +/- 140.63 pmol/mg urinary creatinine) than in the control group (49.42 +/- 45.23 pmol/mg) (P < 0.001). Coefficients of correlation between urinary AM levels and C-reactive protein and white blood cells were statistically significant (r = 0.472, P = 0.041; r = 0.555, P = 0.014, respectively).
Conclusion: Adrenomedullin, a smooth muscle relaxant peptide that is synthesized in urinary tract tissue might have a role in acute pyelonephritis. However, the importance of AM in the pathogenesis of acute pyelonephritis remains to be determined by further detailed studies.