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19–22 APRIL, 2017, BARCELONA, SPAIN
15:47–15:50
S2-5 (PP)
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CONSTIPATION WOULD INDUCE A SENSITIZATION
IN BLADDER NERVES: AN ANIMAL STUDY
Nao IGUCHI
1
, Irfan DÖNMEZ
1
, Anna MALYKHINA
1
and Duncan WILCOX
2
1) University Of Colorado Denver, Surgery, Aurora, USA - 2) Children’s Hospital Colorado, Urology, Aurora, USA
PURPOSE
It has been reported that lower urinary tract symptoms are more frequent in children with consti-
pation and encopresis. The presence of inflammation and muscular hypertrophy in bladders of
constipated children has also been reported. Although the impact of constipation on voiding function
is undisputable, the etiology remains to be elucidated. We hypothesized that in a murine model that
constipation would lead to a change in bladder function through neuronal cross talk.
MATERIAL AND METHODS
Male mice (C57BL/6J, 4-week old) underwent surgery to introduce either reduction of external anal
sphincter opening or sham operation. Sham operated mice were used as controls. Urination and
defecation habits were evaluated at 4, 7, 10, and 14 days post-op. Bladders were subjected to histo-
logical evaluation and in vitro assessment of detrusor contractility following 2 weeks of constipation.
RESULTS
Numbers of urine spots were significantly increased (19 in the constipation group vs. 5 in controls)
while the volume of each void was significantly lower in the constipation group compared to those
in controls (0.17 ml vs. 0.32 ml in controls) at 4 day post-surgery. These parameters were statisti-
cally insignificant between groups on 7, 10 and 14 days. Detrusor strips from constipation group
demonstrated a significantly enhanced contractility in response to electric field stimulation (EFS)
compared to control group by 15%, while no significant difference was observed in response to
high concentration of KCl, or carbachol. This result suggests that the bladder innervating neurons
became sensitized following constipation, which in turn developed the symptoms related to bladder
over activity observed in micturition pattern assessments.
CONCLUSIONS
Our results indicate that constipation caused bladder over activity, which seemed to be induced by
sensitization of innervating neurons.