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BSP-6
(P)
3-D IN VITRO UROTHELIUM INFECTION MODEL USING THE SELF-ASSEMBLY
TECHNIQUE
Stephane BOLDUC, Hazem ORABI, Ingrid SABA and Stephane CHABAUD
CHU de Québec-Université Laval, Surgery, Quebec, CANADA
PURPOSE
Previous in vitro and in vivo studies for investigating the development and differentiation of the urothelium have been
limited, as they do not represent the normal urothelial development and differentiation process in human. Self-assembly
method of matrix formation would form a biomimetic tissue without the need for exogenous materials. In this study, we
aimed at the creation of an ex-vivo urinary bladder model and investigating post-infection effects on the urothelium and
changes in the cytokeratin expression.
MATERIAL AND METHODS
Bladder stromal (BSCs), urothelial (UCs), and smooth muscle cells (SMCs) were isolated using enzymatic methods. BSCs
were stimulated with ascorbate to form collagen sheets. Following, SMCs and UCs were sequentially seeded on the
stacked BSC-sheets to form bladder equivalents. After maturation, constructs were analyzed by histology, mechanical
tests and permeability studies. Then, the ex vivo bladder model was subjected to epithelial bacterial infection. Effects on
urothelial proliferation and keratin expression were noted.
RESULTS
BSCs formed collagen sheets that could be handled easily. UCs constituted a well-differentiated epithelial layer with
biomarkers of impermeability. A well-formed basement membrane and SMCs bundles were identified. Post-infection
effects included decrease in constructs' thickness, urothelial hyperplasia, increased expression of CK14 and loss of CK20
expression, reflecting skin phenotype changes.
CONCLUSIONS
Using the self-assembly, in vitro bladder model was created with many functional and biological similarities to native
bladder tissue without any foreign material. The post-infection changes represent a normal urothelial response to injury,
which if not reversed, may lead to squamous metaplasia of the urothelium.