Increased urinary adrenomedullin excretion in children with urinary-tract infection.
BACKGROUND
Adrenomedullin (AM), a smooth-muscle relaxant peptide, is stimulated by cytokines and bacterial endotoxins. We hypothesized that urinary-tract infections may be associated with elevated urinary AM excretion.


METHODS
AM in urine was quantified in eleven children with urinary-tract infection and 11 age- and sex-matched controls by radioimmunoassay. RT-PCR was used to demonstrate local AM mRNA expression in the urinary tract.


RESULTS
In healthy controls but not in diseased children there was a significant correlation between AM and creatinine in urine (r = 0.91, P < 0.001). AM levels in children with urinary-tract infection were significantly higher than in controls (0.6 +/- 0.41 vs 0.15 +/- 0.14 ng/micromol creatinine; P < 0.001; (means +/- SD)). There was a significant correlation between white cell count and AM in urine (r = 0.78, P < 0.001). AM mRNA was expressed in renal tissue, renal pelvis, ureter, bladder, and urethra.


CONCLUSIONS
The smooth-muscle relaxant peptide adrenomedullin that is synthesized in tissue of the human urinary tract is elevated in urine of patients with urinary-tract infections. A possible consequence might be the interference with the ureteral anti-reflux mechanisms.
Department of Pediatrics, Justus-Liebig-Universität, Giessen, Germany.
J
J
Dötsch
J
J
Hänze
V
V
Knüfer
J O
JO
Steiss
K
K
Dittrich
A
A
Seidel
W
W
Rascher
D053607:Adrenomedullin; D001483:Base Sequence; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D003404:Creatinine / Q000652:urine; D003556:Cystitis / Q000235:genetics / Q000652:urine; D017931:DNA Primers / Q000235:genetics; D005260:Female; D015870:Gene Expression; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007962:Leukocytes / Q000378:metabolism; D008297:Male; D010455:Peptides / Q000235:genetics / Q000652:urine*; D016133:Polymerase Chain Reaction; D011704:Pyelonephritis / Q000235:genetics / Q000652:urine; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014552:Urinary Tract Infections / Q000235:genetics / Q000652:urine*; D014556:Urine / Q000166:cytology
D017931:DNA Primers; D010455:Peptides; D012333:RNA, Messenger; D053607:Adrenomedullin; D003404:Creatinine