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29
th
CONGRESS OF THE ESPU
13:42–13:45
S1-5 (PP)
ROLE OF BDNF IN SUBTOTAL CYSTECTOMY:
FOCUS ON SMOOTH MUSCLE
Karen AITKEN
1
, Martin SIDLER
2
, Aliza SIEBENALLER
3
, Thenuka
THANABALASINGHAM
4
, Arsalan ANEES
5
, Paul DELDELGADO-OLGUIN
6
and
Darius BAGLI
7
1) PGCRL room 159420TUV, DSCB, Sickkids Research Institute, Toronto, CANADA - 2) Hospital for Sick Children,
University of Toronto, Urology Division3, Department of Surgery; Institute of Medical Sciences4, Faculty of Medicine,
Toronto, CANADA - 3) Hospital for Sick Children, Developmental and Stem Cell Biology, Research Institute, Toronto,
CANADA - 4) Hospital for Sick Children, Developmental and Stem Cell Biology, Research Institute, Toronto, CANADA
- 5) Hospital for Sick Children, University of Toronto, Developmental and Stem Cell Biology, Research Institute; HMB,
Faculty of Arts and Sciences, Toronto, CANADA - 6) Hospital for Sick Children, University of Toronto, Developmental and
Stem Cell Biology, Research Institute; Department of Physiology, Faculty of Arts a, Toronto, CANADA - 7) Hospital for
Sick Children, University of Toronto, Developmental and Stem Cell Biology, Research Institute; Department of Surgery,
Faculty of Medicine, Toronto, CANADA
PURPOSE
Dysregulated regeneration is a hallmark in bladder pathobiology, including excessive muscle
growth in partial bladder obstruction (PBO). However, rodent bladders show spontaneous regen-
eration following subtotal cystectomy (STC). Although BDNF is upregulated during PBO, its role in
regeneration is undisputed in the brain and other organs. We hypothesize that BDNF is required for
regeneration of bladder smooth muscle cell (SMC) in response to STC.
MATERIAL AND METHODS
In Sprague-Dawley female rats, 75 % of the bladder was removed, while the remainder was closed
with 7–0 polyglycolic acid sutures forming the STC. These were compared to sham, partial bladder
outlet obstructions (using a 4–0 silk suture) and cystotomy controls. BDNF, calponin and myosin
were assayed by QPCR and immunofluorescence.
Scratch wound assays were performed on human SMC in 12 well plates utilizing a pipette tip and
visualizing by live cell microscopy. Scratched SMC were randomized to treatment with soluble
BDNF receptor (TrkB). Scratch or no wounds were assayed for BDNF by QPCR. Exogenous BDNF
was added to SMC at 2.5, 5 and 10 ng/mL for 24–48 hours, followed by cell by cell counting,
immunofluorescence for calponin and western blotting for myosin expression.
RESULTS
Results: Various BDNF isoforms were differentially upregulated in STC and PBO, p<0.04, sig-
nificantly increasing in both STC (2-fold) and PBO (30–100 fold). High dose BDNF induced de-
differentiation (decreased calponin and myosin), whereas low dose increased proliferation. Scratch
wounding increased BDNF expression 2-fold, p<0.003. Scratch-induced migration was decreased
by soluble TrkB by 15 % (p<0.02).
CONCLUSIONS
Despite BDNF’s association with hypertrophic PBO and neurogenic growth, it appears to have
important functions in endogenous regeneration of the smooth muscle though at lower doses.
Further work will examine the regulatory elements involved, differences between in vivo and in vitro
models and the differential effects of high vs low dose BDNF SMC.