Related Experiment Videos
Increased urinary adrenomedullin excretion in children with urinary-tract infection
Insights
Urinary-tract infections in children are linked to higher levels of adrenomedullin (AM), a peptide found in urine. Elevated AM may affect the urinary tract's natural defense mechanisms.
Area of Science:
- Urology
- Nephrology
- Pediatrics
Background:
- Adrenomedullin (AM) is a peptide with smooth-muscle relaxant properties.
- Cytokines and bacterial endotoxins stimulate AM release.
- Urinary-tract infections (UTIs) are common in children.
Purpose of the Study:
- To investigate the association between urinary-tract infections and urinary adrenomedullin excretion in children.
- To determine if AM levels are elevated in children with UTIs compared to healthy controls.
- To explore the local expression of AM mRNA in the urinary tract.
Main Methods:
- Radioimmunoassay was used to quantify urinary AM levels in 11 children with UTIs and 11 controls.
- Reverse transcription-polymerase chain reaction (RT-PCR) was employed to detect AM mRNA expression.
- Correlation analysis was performed between AM levels, creatinine, and white blood cell count.
Main Results:
- Children with UTIs exhibited significantly higher urinary AM levels compared to controls (0.6 vs. 0.15 ng/micromol creatinine).
- A strong correlation was observed between urinary AM and white cell count in infected children (r = 0.78).
- AM mRNA was detected in various parts of the urinary tract, including the renal tissue, pelvis, ureter, bladder, and urethra.
Conclusions:
- Urinary adrenomedullin is elevated in children with urinary-tract infections.
- The synthesis of AM occurs within the human urinary tract tissues.
- Elevated AM may potentially impair ureteral anti-reflux mechanisms, contributing to UTI pathogenesis.
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.
Conclusion:
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.