Morphological and urodynamic evaluation of urinary bladder wall regeneration: muscles guarantee contraction but not proper function--a rat model research study.
BACKGROUND
Numerous studies are ungoing to develop a substitute for the native urinary bladder wall. The principals of tissue engineering approaches to urinary bladder wall augmentation require a favorable environment for smooth muscle regeneration, which is crucial for bladder function. This study was performed to evaluate bone marrow mesenchymal stem cells (BMSC) seeded on to amniotic membranes fixed to Tachosil sponges as grafts for urinary bladder muscle layer augmentation in a syngenic rat model.


METHODS
Amniotic membranes seeded with BMSC and covered by Tachosil sponges were implanted as multilayer grafts into nine rats to regenerate the urinary bladder wall. The control group consisted of 12 healthy rats. Urodynamic examinations included contraction, elasticity, compliance, and urinary bladder motor activity. Hematocylin and eosin and Masson's trichrome stains were used to evaluate muscle regeneration; histological data were digitally analyzed with the ImageJ tool.


RESULTS
The area of muscle bundles ranged from 5% to 25% or 32% to 41% in control versus reconstructed bladders, respectively. Among nine animals with reconstructed urinary bladders, urodynamic evaluation revealed bladder motor hyperactivity with regular (n = 4) or irregular (n = 1) storage and voiding phases, as well as proper bladder motor activity with a large bladder capacity (n = 1). No bladder contractility was recorded in one case and large stones developed in two animals, which made functional studies impossible.


CONCLUSIONS
Regenerated smooth muscle cells created an autonomic cell population that was poorly assimilated to the rest of the urinary bladder wall. The histological presence of a regenerated muscle layer did not guarantee proper urinary bladder function.
Department of Tissue Engineering, Medical College, N Copernicus University, Torun, Poland.
J
J
Adamowicz
K
K
Juszczak
A
A
Bajek
J
J
Tworkiewicz
M
M
Nowacki
A
A
Marszalek
P J
PJ
Thor
P
P
Chlosta
T
T
Drewa
D000650:Amnion / Q000637:transplantation; D000818:Animals; D049109:Cell Proliferation; D002478:Cells, Cultured; D018920:Coculture Techniques; D003187:Compliance; D004338:Drug Combinations; D005340:Fibrinogen / Q000494:pharmacology; D006801:Humans; D008297:Male; D045164:Mesenchymal Stem Cell Transplantation; D059630:Mesenchymal Stem Cells / Q000187:drug effects / Q000502:physiology; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D051381:Rats; D017208:Rats, Wistar; D012038:Regeneration / Q000187:drug effects; D044968:Regenerative Medicine / Q000379:methods*; D013917:Thrombin / Q000494:pharmacology; D046509:Tissue Culture Techniques; D023822:Tissue Engineering; D054457:Tissue Scaffolds; D001743:Urinary Bladder / Q000187:drug effects / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D014563:Urodynamics / Q000187:drug effects
D004338:Drug Combinations; C518955:TachoSil; D005340:Fibrinogen; D013917:Thrombin